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Sample records for incremental gamma-ray doses

  1. Cellular response to low Gamma-ray doses

    Energy Technology Data Exchange (ETDEWEB)

    Manzanares A, E; Vega C, H R; Leon, L.C. de . [Unidades Academicas de Estudios Nucleares, Universidad Autonoma de Zacatecas, A.P. 336, 98000 Zacatecas (Mexico); Rebolledo D, O; Radillo J, F [Facultad de Ciencias Biologicas y Agropecuarias de la Universidad de Colima, Colima (Mexico)

    2002-07-01

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

  2. Cellular response to low Gamma-ray doses

    International Nuclear Information System (INIS)

    Manzanares A, E.; Vega C, H.R.; Leon, L.C. de; Rebolledo D, O.; Radillo J, F.

    2002-01-01

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

  3. Evaluation of effective dose equivalent from environmental gamma rays

    International Nuclear Information System (INIS)

    Saito, K.; Tsutsumi, M.; Moriuchi, S.; Petoussi, N.; Zankl, M.; Veit, R.; Jacob, P.; Drexler, G.

    1991-01-01

    Organ doses and effective dose equivalents for environmental gamma rays were calculated using human phantoms and Monte Carlo methods accounting rigorously the environmental gamma ray fields. It was suggested that body weight is the dominant factor to determine organ doses. The weight function expressing organ doses was introduced. Using this function, the variation in organ doses due to several physical factors were investigated. A detector having gamma-ray response similar to that of human bodies has been developed using a NaI(Tl) scintillator. (author)

  4. Characteristics of environmental gamma-rays and dose assessment

    International Nuclear Information System (INIS)

    Saito, Kimiaki; Moriuchi, Shigeru

    1986-01-01

    Environmental radioactivity has attracted much attention in terms of exposure to the population, although its exposure doses are minimal. This paper presents problems encountered in the assessment of exposure doses using model and monitoring systems, focusing on the characteristics, such as energy distribution, direction distribution, and site, of environmental gamma-rays. The assessment of outdoor and indoor exposure doses of natural gamma-rays is discussed in relation to the shielding effect of the human body. In the assessment of artificial gamma-rays, calculation of exposure doses using build-up factor, the shielding effect of the human body, and energy dependency of the measuring instrument are covered. A continuing elucidation about uncertainties in dose assessment is emphasized. (Namekawa, K.)

  5. High dose gamma-ray standard

    International Nuclear Information System (INIS)

    Macrin, R.; Moraru, R.

    1999-01-01

    The high gamma-ray doses produced in a gamma irradiator are used, mainly, for radiation processing, i.e. sterilization of medical products, processing of food, modifications of polymers, irradiation of electronic devices, a.s.o. The used absorbed doses depend on the application and cover the range 10 Gy to 100 MGy. The regulations in our country require that the response of the dosimetry systems, used for the irradiation of food and medical products, be calibrated and traceable to the national standards. In order to be sure that the products receive the desired absorbed dose, appropriate dosimetric measurements must be performed, including the calibration of the dosemeters and their traceability to the national standards. The high dose gamma-ray measurements are predominantly based on the use of reference radiochemical dosemeters. Among them the ferrous sulfate can be used as reference dosemeter for low doses (up to 400 Gy) but due to its characteristics it deserves to be considered a standard dosemeter and to be used for transferring the conventional absorbed dose to other chemical dosemeters used for absorbed doses up to 100 MGy. The study of the ferrous sulfate dosemeter consisted in preparing many batches of solution by different operators in quality assurance conditions and in determining for all batches the linearity, the relative intrinsic error, the repeatability and the reproducibility. The principal results are the following: the linear regression coefficient: 0.999, the relative intrinsic error: max.6 %, the repeatability (for P* = 95 %): max.3 %, the reproducibility (P* = 95%): max.5 %. (authors)

  6. Cellular Stress to Low Gamma-ray Dose

    International Nuclear Information System (INIS)

    Manzanares-Acuna, E.; Vega-Carrillo, H. R.; Letechipia de Leon, C.; Guzman Enriquez, L. J.; Garcia-Talavera, M.

    2004-01-01

    The purpose of this study was to evaluate the effect of low gamma ray intensity upon Hsp 70 expression in human lymphocytes. the heat shock proteins (Hsp) family, are a group of proteins present in all living organism, therefore there are highly conserved and are related to adaptation and evolution. At cellular level these proteins acts as chaperones correcting denatured proteins. when a stress agent, such heavy metals, UV, heat, etc. is affecting a cell a response to this aggression is triggered through overexpression of Hsp. Several studies has been carried out in which the cellular effect are observed, mostly of these studies uses large doses, but very few studies are related with low doses. Blood of healthy volunteers was obtained and the lymphocytes were isolated by ficoll-histopaque gradient. Experimental lots were irradiated in a ''137Cs gamma-ray. Hsp70 expression was found since 0.5 cGy, indicating a threshold to very low doses of gamma rays. (Author) 27 refs

  7. In situ measurements of dose rates from terrestrial gamma rays

    International Nuclear Information System (INIS)

    Horng, M.C.; Jiang, S.H.

    2002-01-01

    A portable, high purity germanium (HPGe) detector was employed for the performance of in situ measurements of radionuclide activity concentrations in the ground in Taiwan, at altitudes ranging from sea level to 3900 m. The absolute peak efficiency of the HPGe detector for a gamma-ray source uniformly distributed in the semi-infinite ground was determined using a semi-empirical method. The gamma-ray dose rates from terrestrial radionuclides were calculated from the measured activity levels using recently published dose rate conversion factors. The absorbed dose rate in air due to cosmic rays was derived by subtracting the terrestrial gamma-ray dose rate from the overall absorbed dose rate in air measured using a high-pressure ionization chamber. The cosmic-ray dose rate calculated as a function of altitude, was found to be in good agreement with the data reported by UNSCEAR. (orig.)

  8. Response of human lymphocytes to low gamma ray doses

    International Nuclear Information System (INIS)

    Vega Carrillo, HR; Banuelos Valenzuela, R; Manzanares Acuna, E; Sanchez-Rodriguez, S.H

    2001-01-01

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

  9. Biological dose estimation for accidental supra-high dose gamma-ray exposure

    International Nuclear Information System (INIS)

    Chen, Y.; Yan, X.K.; Du, J.; Wang, Z.D.; Zhang, X.Q.; Zeng, F.G.; Zhou, P.K.

    2011-01-01

    To correctly estimate the biological dose of victims accidentally exposed to a very high dose of 60 Co gamma-ray, a new dose-effect curve of chromosomal dicentrics/multicentrics and rings in the supra-high dose range was established. Peripheral blood from two healthy men was irradiated in vitro with doses of 60 Co gamma-rays ranging from 6 to 22 Gy at a dose rate of 2.0 Gy/min. Lymphocytes were concentrated, cultured and harvested at 52 h, 68 h and 72 h. The numbers of dic + r were counted. The dose-effect curves were established and validated using comparisons with doses from the Tokai-mura accident and were then applied to two victims of supra-high dose exposure accident. The results indicated that there were no significant differences in chromosome aberration frequency among the different culture times from 52 h to 72 h. The 6-22 Gy dose-effect curve was fitted to a linear quadratic model Y = -2.269 + 0.776D - 7.868 x l0 -3 D 2 . Using this mathematic model, the dose estimates were similar to data from Tokai-mura which were estimated by PCC ring. Whole body average doses of 9.7 Gy and 18.1 Gy for two victims in the Jining accident were satisfactorily given. We established and successfully applied a new dose-effect curve of chromosomal dicentrics plus ring (dic + r) after 6-22 Gy γ-irradiation from a supra-high dose 60 Co gamma-ray accident.

  10. Cosmic-ray contribution in measurement of environmental gamma-ray dose

    International Nuclear Information System (INIS)

    Nagaoka, Kazunori; Honda, Kouichirou; Miyano, Keiji

    1996-01-01

    Nowadays several kinds of dosimeters are being used for environmental gamma-ray monitoring. However the results measured by those instruments are not always in good agreement. It may be caused from the different characteristics of dosimeters. In particular the different responses of the instruments to cosmic-rays give significant influence on the results. Environmental radiation measurements at various altitudes on Mt. Fuji were carried out using a scintillation spectrometer with 3''φ spherical NaI(Tl), a pressurized ionization chamber (PIC), an air-equivalent ionization chamber (IC), thermoluminescence dosimeters (TLD), radiophotoluminescence glass dosimeters (RPLD) and NaI(Tl) scintillation survey meters so that the response characteristics of these instruments to cosmic-rays could be clarified. Cosmic-ray contributions for all instruments were correlated with counting rate over 3 MeV by the spectrometer. Each contribution can be estimated by measurement of the counting rate. Conversion factors (nGy/h/cpm) for IC, PIC, TLD, RPLD and NaI survey meters (TCS166 and TCS121C) were 0.33, 0.32, 0.25, 0.24, 0.06 and -0.01, respectively. Self-doses of these instruments were estimated by measurements at Nokogiriyama facilities of the Institute for Cosmic Ray Research, University of Tokyo. Self-doses for TLD and RPLD were approximately 6 nGy/h. The self dose effect should be taken into consideration in environmental dose measurements. These data are expected to be useful in estimating the cosmic-ray contribution and self-dose in the measurement of environmental gamma-ray dose. (author)

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

    CERN Document Server

    Abdel-Latif, A A; Kansouh, W A; El-Sayed, F H

    2003-01-01

    This work is concerned with the study of the leakage gamma ray dose and mass attenuation coefficients for ordinary, basalt and dolomite concretes made from local ores. Concretes under investigation were constructed from gravel, basalt and dolomite ores, and then reconstructed with the addition of 3% steel fibers by weight. Measurements were carried out using a collimated beam from sup 6 sup 0 Co gamma ray source and sodium iodide (3x3) crystal with the genie 2000 gamma spectrometer. The obtained fluxes were transformed to gamma ray doses and displayed in the form of gamma ray dose rates distribution. The displayed curves were used to estimate the linear attenuation coefficients (mu), the relaxation lengths (lambda), half value layer (t sub 1 /2) and tenth value layer (t sub 1 /10). Also, The total mass attenuation coefficients of gamma ray have been calculated to the concerned concretes using XCOM (version 3.1) program and database elements cross sections from Z=1 to 100 at energies from 10 keV to 100 MeV. In...

  12. Comparison of X-ray and gamma-ray dose-response curves for pink somatic mutations in Tradescantia clone 02

    International Nuclear Information System (INIS)

    Underbrink, A.G.; Kellerer, A.M.; Mills, R.E.; Sparrow, A.H.; Brookhaven National Lab., Upton, N.Y.

    1976-01-01

    Microdosimetric data indicate that the mean specific energy, xi, produced by individual charged particles from X rays and gamma rays is different for the two radiation qualities by nearly a factor of two. In order to test whether this influences the initial, linear component in the dose-effect relations, a comparison was made between dose-response curves for pink somatic mutations in Tradescantia clone 02 stamen hairs following X and gamma irradiations. Absorbed doses ranged from 2.66 to 300 rad. The results are in agreement with predictions made on the basis of microdosimetric data. At low doses gamma rays are substantially less effective than X rays. The RBE of gamma rays vs. X rays at low doses was approximately 0.6, a value lower than those usually reported in other experimental systems. (orig.) [de

  13. Measurements of gamma-ray dose from a moderated 252Cf source

    International Nuclear Information System (INIS)

    McDonald, J.C.; Griffith, R.V.; Plato, P.; Miklos, J.

    1983-06-01

    The gamma-ray dose fraction from a moderated 252 Cf source was determined by using three types of dosimetry systems. Measurements were carried out in air at a distance of 35 cm from the surface of the moderating sphere (50 cm from the source which is at the center of the sphere) to the geometrical center of each detector. The moderating sphere is 0.8-mm-thick stainless steel shell filled with D 2 O and covered with 0.5 mm of cadmium. Measurements were also carried out with instruments and dosimeters positioned at the surface of a 40 cm x 40 cm x 15 cm plexiglass irradiation phantom whose front surface was also 35 cm from the surface of the moderating sphere. A-150 tissue-equivalent (TE) plastic ionization chambers and a TE proportional counter (TEPC) were used to measure tissue dose, from which the neutron dose equivalent was computed. The ratio of gamma-ray dose to the neutron dose equivalent was determined by using a relatively neutron-insensitive Geiger-Mueller (GM) counter and thermoluminescent dosimeters (TLD). In addition, the event-size spectrum measured by the TEPC was also used to compute the gamma-ray dose fraction. The average value for the ratio of gamma-ray dose to neutron dose equivalent was found to be 0.18 with an uncertainty of about +-18%

  14. Distribution and characteristics of gamma and cosmic ray dose rate in living environment

    International Nuclear Information System (INIS)

    Nagaoka, Toshi; Moriuchi, Shigeru

    1991-01-01

    A series of environmental radiation surveys was carried out from the viewpoint of characterizing the natural radiation dose rate distribution in the living environment, including natural and artificial ones. Through the analysis of the data obtained at numbers of places, several aspects of the radiation field in living environments were clarified. That is the gamma ray dose rate varies due to the following three dominant causes: 1) the radionuclide concentration of surrounding materials acting as gamma ray sources, 2) the spatial distribution of surrounding materials, and 3) the geometrical and shielding conditions between the natural gamma ray sources and the measured point; whereas, the cosmic ray dose rate varies due to the thickness of upper shielding materials. It was also suggested that the gamma ray dose rate generally shows an upward tendency, and the cosmic ray dose rate a downward one in artificial environment. This kind of knowledge is expected to serve as fundamental information for accurate and realistic evaluation of the collective dose in the living environment. (author)

  15. TL detectors for gamma-ray dose measurements in critically accidents

    International Nuclear Information System (INIS)

    Miljanic, S.; Knezevic, Z.; Zorko, B.; Gregori, B.

    2005-01-01

    Full text: Determination of gamma-ray dose in mixed neutron + gamma-ray fields is still a challenging task. Dosemeters used for gamma-ray dosimetry are usually in some extent sensitive to neutrons and their response variations depend on neutron energy i.e. on neutron spectra. Besides, it is necessary to take into account the energy dependence of dosimeter responses to gamma-rays. To reduce all these influences, design of dosemeter holders is of special importance. In this work, several types of thermoluminescent detectors (TLD) placed in different holders used for gamma-ray dose determination in mixed fields were examined. Dosemeters were from three different institutions: Ruder Boscovic Institute (RBI), Croatia, Jozef Stefan Institute (JSI), Slovenia and Autoridad Regulatoria Nuclear (ARN), Argentina. All dosemeters were irradiated during the International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE Reactor, Valduc, June 2002. At that exercise three accidental scenarios were reproduced: bare reactor, free evolution; lead shielded reactor, steady state; and lead shielded reactor, free evolution. In each irradiation dosemeters were exposed placed on the front of phantom and 'free-in-air'. Also, dosemeters were irradiated in a pure gamma ray field of 60 Co source. Following types of TLDs were used: 7 LiF (TLD-700), CaF 2 :Mn and AI 2 O 3 :Mg,Y - all from RBI; CaF 2 :Mn from JSI and 7 LiF (TLD-700) from ARN. Reported doses were compared with the reference values as well as with the mean participants' values. The results show satisfactory agreement with other dosimetry systems used in the Intercomparison. The influence of different types of holders and applied corrections of dosemeters' readings are discussed. (author)

  16. Dose Rate Determination from Airborne Gamma-ray Spectra

    DEFF Research Database (Denmark)

    Bargholz, Kim

    1996-01-01

    The standard method for determination of ground level dose rates from airborne gamma-ray is the integral count rate which for a constant flying altitude is assumed proportional to the dose rate. The method gives reasonably results for natural radioactivity which almost always has the same energy...

  17. TL detectors for gamma ray dose measurements in criticality accidents

    International Nuclear Information System (INIS)

    Miljanic, S.; Zorko, B.; Gregori, B.; Knezevic, Z.

    2007-01-01

    Determination of gamma ray dose in mixed neutron + gamma ray fields is still a demanding task. Dosemeters used for gamma ray dosimetry are usually in some extent sensitive to neutrons and their response variations depend on neutron energy i.e., on neutron spectra. Besides, it is necessary to take into account the energy dependence of dosemeter responses to gamma rays. In this work, several types of thermoluminescent detectors (TLD) placed in different holders used for gamma ray dose determination in the mixed fields were examined. Dosemeters were from three different institutions: Ruder Boskovic Inst. (RBI), Croatia, Jozef Stefan Inst. (JSI), Slovenia and Autoridad Regulatoria Nuclear (ARN), Argentina. All dosemeters were irradiated during the International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE Reactor, Valduc, June 2002. Three accidental scenarios were reproduced and in each irradiation the dosemeters were exposed placed on the front of phantom and 'free in air'. Following types of TLDs were used: 7 LiF (TLD-700), CaF 2 :Mn and Al2 O3 :Mg,Y - all from RBI; CaF 2 :Mn from JSI and 7 LiF (TLD-700) from ARN. Reported doses were compared with the reference values as well as with the values obtained from the results of all participants. The results show satisfactory agreement with other dosimetry systems used in the Intercomparison. The influence of different types of holders and applied corrections of dosemeters' readings are discussed. (authors)

  18. TL detectors for gamma ray dose measurements in criticality accidents.

    Science.gov (United States)

    Miljanić, Saveta; Zorko, Benjamin; Gregori, Beatriz; Knezević, Zeljka

    2007-01-01

    Determination of gamma ray dose in mixed neutron+gamma ray fields is still a demanding task. Dosemeters used for gamma ray dosimetry are usually in some extent sensitive to neutrons and their response variations depend on neutron energy i.e., on neutron spectra. Besides, it is necessary to take into account the energy dependence of dosemeter responses to gamma rays. In this work, several types of thermoluminescent detectors (TLD) placed in different holders used for gamma ray dose determination in the mixed fields were examined. Dosemeters were from three different institutions: Ruder Bosković Institute (RBI), Croatia, JoZef Stefan Institute (JSI), Slovenia and Autoridad Regulatoria Nuclear (ARN), Argentina. All dosemeters were irradiated during the International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE Reactor, Valduc, June 2002. Three accidental scenarios were reproduced and in each irradiation the dosemeters were exposed placed on the front of phantom and 'free in air'. Following types of TLDs were used: 7LiF (TLD-700), CaF2:Mn and Al2O3:Mg,Y-all from RBI; CaF2:Mn from JSI and 7LiF (TLD-700) from ARN. Reported doses were compared with the reference values as well as with the values obtained from the results of all participants. The results show satisfactory agreement with other dosimetry systems used in the Intercomparison. The influence of different types of holders and applied corrections of dosemeters' readings are discussed.

  19. Gamma ray doses proceeding from natural occurring radionuclides in closed environments

    International Nuclear Information System (INIS)

    Aguiar, Vitor Angelo P. de; Medina, Nilberto H.; Silveira, Marcilei A. Guazzelli da; Moreira, Ramon H.

    2009-01-01

    In this work we report on the application of gamma-ray spectrometry in the study of the effective dose coming from terrestrial natural elements present in building materials such as sand, cement, lime (CaO) and milled granitic stones. The major contribution to annual gamma-ray radiation effective dose is due to the natural occurring radionuclides 40 K, 232 Th and 238 U. Two spectrometry systems were employed to measure the gamma radiation: one with a 60% efficient GeHP detector and the second one with a 2''x2'' NaI(Tl) scintillator. The estimated effective dose coming from the three reference rooms assumed is 0.63 mSv/yr, proceeding from terrestrial natural elements. The principal gamma radiation sources are cement, sand and bricks. (author)

  20. Specific gamma-ray dose constants for nuclides important to dosimetry and radiological assessment

    International Nuclear Information System (INIS)

    Unger, L.M.; Trubey, D.K.

    1982-05-01

    Tables of specific gamma-ray dose constants (the unshielded gamma-ray dose equivalent rate at 1 m from a point source) have been computed for approximately 500 nuclides important to dosimetry and radiological assessment. The half life, the mean attenuation coefficient, and thickness for a lead shield providing 95% dose equivalent attenuation are also listed

  1. Neutron and gamma-ray dose-rates from the Little Boy replica

    International Nuclear Information System (INIS)

    Plassmann, E.A.; Pederson, R.A.

    1984-01-01

    We report dose-rate information obtained at many locations in the near vicinity of, and at distances out to 0.64 km from, the Little Boy replica while it was operated as a critical assembly. The measurements were made with modified conventional dosimetry instruments that used an Anderson-Braun detector for neutrons and a Geiger-Mueller tube for gamma rays with suitable electronic modules to count particle-induced pulses. Thermoluminescent dosimetry methods provide corroborative data. Our analysis gives estimates of both neutron and gamma-ray relaxation lengths in air for comparison with earlier calculations. We also show the neutron-to-gamma-ray dose ratio as a function of distance from the replica. Current experiments and further data analysis will refine these results. 7 references, 8 figures

  2. Calculation of neutron and gamma-ray flux-to-dose-rate conversion factors

    International Nuclear Information System (INIS)

    Kwon, S.G.; Lee, S.Y.; Yook, C.C.

    1981-01-01

    This paper presents flux-to-dose-rate conversion factors for neutrons and gamma rays based on the American National Standard Institute (ANSI) N666. These data are used to calculate the dose rate distribution of neutron and gamma ray in radiation fields. Neutron flux-to-dose-rate conversion factors for energies from 2.5 x 10 -8 to 20 MeV are presented; the corresponding energy range for gamma rays is 0.01 to 15 MeV. Flux-to-dose-rate conversion factors were calculated, under the assumption that radiation energy distribution has nonlinearity in the phantom, have different meaning from those values obtained by monoenergetic radiation. Especially, these values were determined with the cross section library. The flux-to-dose-rate conversion factors obtained in this work were in a good agreement to the values presented by ANSI. Those data will be useful for the radiation shielding analysis and the radiation dosimetry in the case of continuous energy distributions. (author)

  3. Effect of gamma rays on M1 generation in basmati rice

    International Nuclear Information System (INIS)

    Ashraf, M.; Cheema, A.A.; Rashid, M.; Zia-ul-Qamar

    2003-01-01

    To estimate the sensitivity to gamma rays in Basmati rice, five varieties namely Basmati 370, Basmati Pak, Basmati 385, Super Basmati and Basmati 2000were exposed to different doses of gamma rays ranging 150- 350 Gy with an increment of 50 Gy among the doses. Plant growth parameters such as seedling shoot and root lengths were measured in the laboratory. Highly significant differences were observed among the varieties for seedling shoot and root lengths. Radiations showed highly significant negative correlations with seedling shoot length (-0.998), seedling root length (-0.941) showing dose dependent responses. Highly significant negative correlations with panicle fertility (-0.941) and grain yield (-0.971), and significant negative correlation for seedling emergence (-0.941) showed detrimental dose dependent responses.Seedling emergence, panicle fertility and grain yield declined with increasing dose level in all the varieties. The dose at which panicle fertility halved was 260.37 Gy. Basmati 2000 was observed to be the most sensitive followed by Basmati 370, Super Basmati and Basmati Pak, but Basmati 385 was found to be the least sensitive variety to gamma rays

  4. Gamma-Ray Doses Affected on Alfalfa (Medicago sativa L.)

    International Nuclear Information System (INIS)

    Zayed, E.M; Tarrad, M.M.; Abd El-Daem, G.A.N.A.

    2013-01-01

    Field experiments were conducted at the experimental from, Nuclear Research Center at Inshas. Atomic Energy Authority (AEA) at Egypt during 2011– 2012 growing seasons on alfalfa genotype. The aim of this investigation to evaluate the effect of different gamma ray doses (100-300 Gy) on the alfalfa yield and related traits. Seeds lots of alfalfa genotype were subjected to five gamma ray treatments (100,150,200,250 and 300 Gray). Over all cuts, the dose treatment 300 Gy increased the majority of studied traits i.e., plant height, No. of shoots/plant, fresh weight/plant, fresh yield/Fadden and dry weight yield/fed. The results observed indicated that. In addition, dose of 200 and 250 Gy increased No. of leaves /plant, No. of shoots/plant, stem diameter and fresh weight /plant. However, the plant dry weight was decreased by all doses used and over all cuts, but the dose of 100 and 150 Gy increased leaves /stem ratio. Meanwhile, the later cuts were more affected by irradiation treatments than the earlier ones. In general, the low doses had negative effects on yield traits, but, the relatively high doses exhibited an increase in yield traits

  5. American National Standard: neutron and gamma-ray flux-to-dose rate factors

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    This Standard presents data recommended for computing biological dose rates due to neutron and gamma-ray radiation fields. Neutron flux-to-dose-rate conversion factors for energies from 2.5 x 10 -8 to 20 MeV are given; the energy range for the gamma-ray conversion factors is 0.01 to 15 MeV. Specifically, this Standard is intended for use by shield designers to calculate wholebody dose rates to radiation workers and the general public. Establishing dose-rate limits is outside the scope of this Standard. Use of this Standard in cases where the dose equivalents are far in excess of occupational exposure guidelines is not recommended

  6. Organ doses for foetuses, babies, children and adults from environmental gamma rays

    International Nuclear Information System (INIS)

    Petoussi, N.; Jacob, P.; Zankl, M.; Saito, K.

    1991-01-01

    Organ doses for babies, children and adults and doses to foetuses from environmental gamma rays were calculated using Monte Carlo codes. Firstly, gamma ray fields in the air-over-ground geometry were simulated, neglecting the disturbances of the radiation field by the human body. The exposure modes considered were semi-infinite homogeneous volume sources in the air, infinite plane sources at a depth of 0.5 g.cm -2 in the ground and homogeneous volume sources of natural radionuclides in the ground. The results of the simulation of the gamma ray transport in the air-over-ground geometry were used as sources irradiating the anthropomorphic phantoms: an 8 week old baby, a seven year old child and two 'reference' adult phantoms of a male and a female. The dose to foetuses were estimated from the dose to the uterus of the adult female. Dose conversion factors normalised to source intensity and air kerma were calculated for monoenergetic sources (15 keV to 10 MeV) and natural and artificial radionuclides. (author)

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

    International Nuclear Information System (INIS)

    Yasuhiro Ohsima; Mitsutoshi Tukimoto; Shuji Kojima

    2007-01-01

    Complete text of publication follows. A lot of beneficial effects of low-dose irradiation are well known. Of them, an inhibitory effect of the radiation on lung metastasis is reported so far. It has been reported that low-dose whole-body irradiation with gamma rays enhanced cytotoxic immune response as one of the mechanisms. In our laboratory, it has been confirmed an enhancement of natural killer activity in mice irradiated with whole-body 0.5Gy gamma-rays. Metastasis is accomplished by multistep process, involving basement membrane destruction, local invasion, intravasation, survival in the bloodstream, extravasation into distant organs, and proliferation at the target site. Besides, a lot of growth factors and proteases are involved in these steps. As to mechanism of inhibition of tumor metastasis induced by low-dose whole-body irradiation, studies from the standpoint of tumor invasion have not been reported. Here, inhibitory effect of 0.5Gy whole-body gamma-ray irradiation on tumor metastasis and its mechanism were examined in pulmonary metastasis model mice injected with B16 melanoma cells. Consequently, 0.5Gy whole-body gamma ray irradiation significantly suppressed colony formation in the lungs. Expression of matrix metalloproteinase- 2 (MMP- 2), a proteinase related to metastasis, in lung tissues was suppressed by the radiation. Alteration of tissue inhibitor of matrix metalloproteinase (TIMP) after the gamma-ray irradiation was examined. Expression of TIMP-1 and TIMP-2 mRNA in the lungs were significantly increased. In order to clarify the inhibitory effect obtained in the in vivo metastatic lung cancer model mice, we studied effects of gamma-rays on cell proliferation, alterations of mRNA and proteins related to tumor metastasis in cultured B16 melanoma cells. Proliferation of B16 melanoma cells was decreased in a dose-dependent manner. MMP-2 mRNA expression was not altered in any doses of gamma-rays. Thought expression of the protein was slightly

  8. Evaluation of skyshine dose due to gamma-rays from a cobalt-60 irradiation facility

    International Nuclear Information System (INIS)

    Kanazawa, Tamotsu; Okamoto, Shinichi; Ohnishi, Tokuhiro; Tsujii, Yukio

    1991-01-01

    We attempted to evaluate skyshine dose due to gamma-rays from a cobalt-60 irradiation facility. As the first step, the results of measurements and calculations were compared of the skyshine dose due to gamma-rays from the cobalt-60 source of 1.45 PBq set in the No.4 irradiation room of our laboratory. Distances of measuring points from the cobalt source were in the range from 17 m to about 100 m in the site of our office. Calculation was carried out with simplified single scattering method. The calculated values of the skyshine dose were higher than the measured values. For more precise evaluation of the skyshine dose, the following factors are to be considered; the dose rate distribution on the roof above the source and the attenuation of gamma-rays by air. (author)

  9. Effect of large dose gamma-ray irradiation on polyimide

    International Nuclear Information System (INIS)

    Morita, Yohsuke; Watanabe, Kiyoshi; Yagyu, Hideki.

    1988-01-01

    In the radiation environment of atomic energy, space and so on, with the heightening of the performance of equipment, the organic materials having the radiation resistance up to several hundreds MGy have been demanded. Polyimide is one of a small number of the polymers which are considered to be applicable to such environment. However, actually the characteristics as the insulator for such large dose radiation environment have not been sufficiently verified. In this study, the gamma-ray of as large dose as 100 MGy was irradiated on the polyimides having different chemical structure in the air and in nitrogen, and the change of their mechanical and electrical characteristics was elucidated, at the same time, the structural change was examined. The four kinds of polyimides used for the experiment were three kinds of thermosetting type and thermoplastic polyether imide. Co-60 gamma-ray was irradiated at the dose rate of 17 kGy/h at room temperature. The tensile properties, volume resistivity, dielectric tangent, gel fraction, glass transition temperature and IR spectra were examined. In the air, the characteristics lowered by large dose irradiation due to the severance of main chains. In nitrogen, the deterioration was extremely slight, and cross-linking occurred. (K.I.)

  10. Suitable gamma ray dose determination in order to induce genetic variation in kaboli chickpea (Cicer Arietinum L)

    International Nuclear Information System (INIS)

    Naserian Khiabani, B.; Ahari Mostafavi, H.; Fathollahi, H.; Vedadi, S.; Mosavi Shalmani, M. A.

    2008-01-01

    In spite of chickpea's use in Iran and its ability of being replaced to adjust the shortage of protein in dietary habits, yield production is very low. One of the main reasons for chickpea's low yield production is its sensitiveness to some diseases, pest and environmental stresses. Genetic variation in chickpea is very low, because of its self pollination. In breeding programs, genetic variation plays an essential role so that the induction of genetic variation in plant population is very important for the plant breeders. The induced mutation through different kinds of mutagens is one of the important ways of genetic variation. In this research, first the sensitiveness of four cultivars (ILC.486, Philip86, Bivinich, Jam) were assessed to different gamma ray doses (100, 200, 300, 400 Gy). The results showed that with an increase in gamma ray dose, the growth rate of chickpea's genotypes decreases. In this respect, the decrease of growth rate has a linear relationship with the gamma ray dose and it is independent from the genotypes. The root length is more sensitive to gamma ray doses than its shoot, and it was observed that at the low doses the root growth decreases, comparing to the shoot growth. On the other hand, in high doses of gamma ray growth abrasion (Ageotropism, Albinism and etc.) were observed. Some traits variation (such as leaf shape, leaf size, leaf color, Albinism, etc.) were seen in M 2 generation, and finally to continue the project, three doses of gamma ray (150,200,250) were selected for the next year

  11. Determination of gamma ray doses suitable for mutation induction in garlic (Allium sativum L.)

    International Nuclear Information System (INIS)

    Al-Safadi, Bassam; Ayyoubi, Zouhair

    1993-04-01

    Garlic (Allium sativum L.) cloves were exposed to different doses of gamma radiation (Control, 100, 250, 500, 750, and 1000 rads). The cloves were planted in 4 replicates at Deer Alhajar station of the Dept. of Radiation Agriculture. Number of surviving plants was recorded at 2 months after planting and at harvest. Length of foliage was measured at harvest time and weight of cloves was taken two weeks after harvest. Visual readings in the field on plant shape and leaf color were also taken. The results indicated a negative effect of gamma radiation on plant survival especially at doses of 750 and 1000 rads where no plants survived until harvest. Plant length and clove weight were reduced even at 500 rad dose. Percentage of yellow and necrotic plants increased with increasing gamma ray dosage. No stimulation of plant growth was noticed as a result of irradiation with low doses of gamma rays. Treatment with 500 rads of gamma radiation was considered the best among tested doses for garlic mutagenesis (Using cloves) since it gave acceptable rate of survival and morphologic variation. (author). 14 refs., 4 figs

  12. A Performance Evaluation of a Notebook PC under a High Dose-Rate Gamma Ray Irradiation Test

    Directory of Open Access Journals (Sweden)

    Jai Wan Cho

    2014-01-01

    Full Text Available We describe the performance of a notebook PC under a high dose-rate gamma ray irradiation test. A notebook PC, which is small and light weight, is generally used as the control unit of a robot system and loaded onto the robot body. Using TEPCO’s CAMS (containment atmospheric monitoring system data, the gamma ray dose rate before and after a hydrogen explosion in reactor units 1–3 of the Fukushima nuclear power plant was more than 150 Gy/h. To use a notebook PC as the control unit of a robot system entering a reactor building to mitigate the severe accident situation of a nuclear power plant, the performance of the notebook PC under such intense gamma-irradiation fields should be evaluated. Under a similar dose-rate (150 Gy/h gamma ray environment, the performances of different notebook PCs were evaluated. In addition, a simple method for a performance evaluation of a notebook PC under a high dose-rate gamma ray irradiation test is proposed. Three notebook PCs were tested to verify the method proposed in this paper.

  13. Effect of Low Dose gamma-ray Irradiation on the Germination and Growth in Red Pepper (Capcicum annuum L.)

    International Nuclear Information System (INIS)

    Lee Eun-Kyung; Kim Jae-Sung

    1998-01-01

    This study was conducted to determine the effect of low dose gamma-ray irradiation in red pepper. The germination percentage, plant, the number of flower, chlorophyll contents, leaf length and width were observed from plants grown with red pepper seeds irradiated with various low dose of gamma-ray. The germination percentage of irradiation group treatmented gamma-ray was much higher than that of the control. Specially the germination percentage after sowing red pepper seeds on paper towel was higher than 1,000 and 2,000 rad irradiation group. The height of plants grown with red pepper seeds irradiated with gamma-ray was increased in 100, 200 and 400 rad irradiation group compared to that of the control. The height of plant from 2,400 rad irradiation group, however, was shorter than that of the control. Nutrient contents of leaves of plants grown with red pepper seeds irradiated with various dose of gamma-ray were significantly increased in 800 and 1,200 rad irradiation group. Electric conductivity (EC) of the water used for seed germination was lower irradiation group than control group. Therefore, there was the possibility to increase the germination and plant growth with gamma-ray of adequate low dose

  14. Yield and Chemical Composition of Cucumber Treated by Nitrogen Levels and Doses of Gamma Rays

    International Nuclear Information System (INIS)

    Fath El-Bab, T.Sh.; Abo El-Khier, Om.M.; Abdallah, A.A.G.

    2013-01-01

    Two field experiments were performed at the Atomic Energy Authority, Experimental farm, Inshas, Egypt during 2010 and 2011 summer growing seasons in sandy soil. The experiments were conducted to study the effect of pre-sowing seeds which treated by gamma irradiation with different doses of 0, 2, 4 and 6 Gy. This was in combination with three rates of nitrogen, fertilizer i.e., 30, 60 and 90 Kg N/fed. The experiments were laid out using drip irrigation system. The obtained results indicated that gamma rays doses showed significant differences on cucumber yield per plot or per Fed., increasing doses of gamma rays gradually increased cucumber yield per plot up to highest dose, i.e., (6 Gy). The highest value of total yield was obtained with the highest nitrogen rate (90 Kg N/fed.). Doses of gamma rays significantly increased total soluble solids (T.S.S.), total Carbohydrates, fats, total protein, NPK and Ca of cucumber fruits. Application of 60 Kg N/fed. recorded the highest values of all above mentioned chemical characters except of total protein with 90 kg N/fed. every all dose treatments. The effect of interaction between doses and fertilizer levels on chemical characters were significant therefore, the highest values was found at 4 Gy and 60 Kg N/fed. treatment for protein, fat, nitrogen and potassium contents while the carbohydrate and calcium contents had the highest value with the treatment of 6 Gy and 60 Kg N/fed

  15. Effect of gamma irradiation dose on the fabrication of α-elastin nanoparticles by gamma-ray crosslinking

    International Nuclear Information System (INIS)

    Fujimoto, Mari; Takeda, Mayuko; Okamoto, Kouji; Furuta, Masakazu

    2011-01-01

    Nanoparticles were prepared utilizing the thermosensitive aggregation of α-elastin and gamma-ray crosslinking. We investigated the effect of the α-elastin irradiation doses to verify the yield of crosslinked nanoparticles. Aqueous solution of α-elastin (10 mg/ml) was used for the aggregation on raising temperature above its cloudy point (CP), followed by gamma-ray crosslinking. A slow heating process (1.9 o C/min) effectively led to aggregation of polypeptide and irradiation with more than 15 kGy yielded stable crosslinked nanoparticles with diameters less than ca. 200 nm and a narrow size distribution.

  16. Effect of gamma irradiation dose on the fabrication of {alpha}-elastin nanoparticles by gamma-ray crosslinking

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Mari; Takeda, Mayuko [Department of Biological Science, Graduate School of Science, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8570 (Japan); Okamoto, Kouji [Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Iizuka, Fukuoka 820-8502 (Japan); Furuta, Masakazu, E-mail: mfuruta@b.s.osakafu-u.ac.j [Department of Biological Science, Graduate School of Science, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8570 (Japan)

    2011-02-15

    Nanoparticles were prepared utilizing the thermosensitive aggregation of {alpha}-elastin and gamma-ray crosslinking. We investigated the effect of the {alpha}-elastin irradiation doses to verify the yield of crosslinked nanoparticles. Aqueous solution of {alpha}-elastin (10 mg/ml) was used for the aggregation on raising temperature above its cloudy point (CP), followed by gamma-ray crosslinking. A slow heating process (1.9 {sup o}C/min) effectively led to aggregation of polypeptide and irradiation with more than 15 kGy yielded stable crosslinked nanoparticles with diameters less than ca. 200 nm and a narrow size distribution.

  17. New model for assessing dose and dose rate sensitivity of Gamma ray radiation loss in polarization maintaining optical fibers

    International Nuclear Information System (INIS)

    Zhang Hongchen; Liu Hai; Qiao Wenqiang; Xue Huijie; He Shiyu

    2012-01-01

    Highlights: ► Building a new phenomenological theory model to investigate the relation about the irradiation induced loss with irradiation dose and dose rate. ► The Gamma ray irradiation induced loss of the “Capsule” type and “Panda” type polarization maintaining optical fibers at 1310 nm wavelength are investigated. ► The anti irradiation performance of the “Panda” type polarization maintaining optical fiber is better than that of the “Capsule” type polarization maintaining optical fiber, the reason is that the stress region doped by GeO 2 . - Abstract: The Gamma ray irradiation induced loss of the “Capsule” type and “Panda” type polarization maintaining optical fibers at 1310 nm wavelength are investigated. A phenomenological theory model is introduced and the influence of irradiation dose and dose rate on the irradiation induced loss is discussed. The phenomenological theoretical results are consistent with the experimental results of the irradiation induced loss for the two types of polarization maintaining optical fibers. The anti irradiation performance of the “Panda” type polarization maintaining optical fiber is better than that of the “Capsule” type polarization maintaining optical fiber, the reason is that the stress region dope with GeO 2 . Meanwhile, both of the polarization maintaining optical fiber irradiation induced loss increase with increasing the irradiation dose. In the case of same dose, the high dose rate Gamma ray irradiation induced optical fiber losses are higher than that of the low dose rate.

  18. Cytosolic Hsp70/Hsc70 protein expression in lymphocytes exposed to low gamma-ray dose

    International Nuclear Information System (INIS)

    Manzanares A, E.; Vega C, H.R.; Letechipia de Leon, C.; Guzman E, L.J.; Garcia T, M.

    2004-01-01

    The purpose of this study was to evaluate the effect of low gamma ray intensity upon Hsp70 expression in human Iymphocytes. The heat shock proteins (Hsp) family, are a group of proteins present in all living organism, therefore there are highly conserved and are related to adaptation and evolution. At cellular level these proteins acts as chaperones correcting denatured proteins. When a stress agent, such heavy metals, UV, heat, etc. is affecting a cell a response to this aggression is triggered only through over expression of Hsp. Several studies has been carried out in which the cellular effect are observed, mostly of these studies uses large doses, but very few studies are related with low doses. Blood of healthy volunteers was obtained and the Iymphocytes were isolated by ficoll- histopaque gradient. Experimental lots were irradiated in a 137 Cs gamma-ray. Hsp70 expression was found since 0.5 c Gy, indicating a threshold to very low doses of gamma rays. (Author)

  19. Cytosolic Hsp70/Hsc70 protein expression in lymphocytes exposed to low gamma-ray dose

    Energy Technology Data Exchange (ETDEWEB)

    Manzanares A, E.; Vega C, H.R.; Letechipia de Leon, C. [Unidades Academicas de Estudios Nucleares, UAZ, A.P. 336, 98000 Zacatecas (Mexico)]. E-mail: emanz@cantera.reduaz.mx; Guzman E, L.J. [Unidad Academica de Biologia Experimental, Guadalupe, Zacatecas (Mexico); Garcia T, M. [LIBRA, Centro I and D, Campus Miguel Delibes, Valladolid 47011 (Spain)

    2004-07-01

    The purpose of this study was to evaluate the effect of low gamma ray intensity upon Hsp70 expression in human Iymphocytes. The heat shock proteins (Hsp) family, are a group of proteins present in all living organism, therefore there are highly conserved and are related to adaptation and evolution. At cellular level these proteins acts as chaperones correcting denatured proteins. When a stress agent, such heavy metals, UV, heat, etc. is affecting a cell a response to this aggression is triggered only through over expression of Hsp. Several studies has been carried out in which the cellular effect are observed, mostly of these studies uses large doses, but very few studies are related with low doses. Blood of healthy volunteers was obtained and the Iymphocytes were isolated by ficoll- histopaque gradient. Experimental lots were irradiated in a {sup 137} Cs gamma-ray. Hsp70 expression was found since 0.5 c Gy, indicating a threshold to very low doses of gamma rays. (Author)

  20. Cesium adsorption ability and stability of metal hexacyanoferrate irradiated with gamma-rays

    International Nuclear Information System (INIS)

    Arisaka, Makoto; Watanabe, Masayuki; Ishizaki, Manabu; Kurihara, Masato; Chen, Rongzhi; Tanaka, Hisashi

    2013-01-01

    The influence of irradiation with gamma-rays to metal hexacyanoferrate (MHCF: M = Fe, Cu or Ni), which is known as an adsorbent for selective adsorption of cesium (Cs) ion in solution, on Cs adsorption ability and stability was investigated in HNO 3 solutions. Under the adsorbed dose conditions (50 - 300 kGy), it was found that the MHCF is fully stable although the radiolytic decomposition of MHCF was slightly observed with an increase of the total adsorbed dose, which was confirmed by an increment of Fe, Cu or Ni concentration in HNO 3 solution after the irradiation. The weight percent of the metal in the solution to initial weight of MHCF was less than unity. Moreover, no change in composition of carbon, hydrogen and nitrogen in MHCF was observed. On the other hand, the distribution coefficients of Cs to the irradiated MHCF were independent of the total adsorbed dose. This indicates that the Cs adsorption ability was maintained under gamma-ray irradiation. (author)

  1. Effects of low dose gamma-ray radiation on the seed germination and physiological activity of vegetable crops

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. S.; Baek, M. H.; Lee, Y. G. [KAERI, Taejon (Korea, Republic of); Jung, K. H. [Kyunghee Univ., Yongin (Korea, Republic of)

    2000-10-01

    To determine the effect of low dose gamma-ray radiation on the germination rate and physiology of germinative seeds of Chinese cabbage(Brassica campestris L. cv. Hanyoreum) and radish(Raphanus sativus L. cv. Chungsukoungzoung). The germination rate of irradiation group was higher than that of the control. Especially it was highest at the early stage of induction. The germination rate of Chinese cabbage increased at 4 Gy-, 10 Gy- and 50 Gy irradiation group and that of radish increased at 2 Gy-, 6 Gy- and 10 Gy irradiation group. The seedling height of Chinese cabbage and radish increased positively in low dose irradiation group. The seedling height of Chinese cabbage was noticeably higher at 4 Gy and 10 Gy irradiation group and that of radish at 6 Gy irradiation group. The protein contents of seeds irradiated with low dose gamma-ray radiation was increased compared to that of the control especially at the early stage of induction. The enzyme activity of seeds irradiated with low dose of gamma-ray radiation was increased at 4 Gy and 10 Gy irradiation group. These results suggest that the germination and physiological activity of old seeds could be stimulated promisingly by the low dose gamma-ray radiation.

  2. Fieldable computer system for determining gamma-ray pulse-height distributions, flux spectra, and dose rates from Little Boy

    International Nuclear Information System (INIS)

    Moss, C.E.; Lucas, M.C.; Tisinger, E.W.; Hamm, M.E.

    1984-01-01

    Our system consists of a LeCroy 3500 data acquisition system with a built-in CAMAC crate and eight bismuth-germanate detectors 7.62 cm in diameter and 7.62 cm long. Gamma-ray pulse-height distributions are acquired simultaneously for up to eight positions. The system was very carefully calibrated and characterized from 0.1 to 8.3 MeV using gamma-ray spectra from a variety of radioactive sources. By fitting the pulse-height distributions from the sources with a function containing 17 parameters, we determined theoretical repsonse functions. We use these response functions to unfold the distributions to obtain flux spectra. A flux-to-dose-rate conversion curve based on the work of Dimbylow and Francis is then used to obtain dose rates. Direct use of measured spectra and flux-to-dose-rate curves to obtain dose rates avoids the errors that can arise from spectrum dependence in simple gamma-ray dosimeter instruments. We present some gamma-ray doses for the Little Boy assembly operated at low power. These results can be used to determine the exposures of the Hiroshima survivors and thus aid in the establishment of radation exposure limits for the nuclear industry

  3. Life span and tumorigenesis in mice exposed to continuous low dose-rate gamma-rays

    International Nuclear Information System (INIS)

    Tanaka, Satoshi; Braga-Tanaka III, Ignacia; Takabatake, Takashi; Ichinohe, Kazuaki; Tanaka, Kimio; Matsumoto, Tsuneya; Sato, Fumiaki

    2004-01-01

    Two experiments were conducted to evaluate late biological effects of chronic low dose-rate radiation. 1: Late effects of chronic low dose-rate gamma-ray irradiation on SPF mice, using life span and pathological changes as parameters. Continuous irradiation for approximately 400 days was performed using 137 Cs gamma-rays at dose-rates of 20 mGy/day, 1 mGy/day and 0.05 mGy/day with accumulated doses equivalent to 8000 mGy, 400 mGy and 20 mGy, respectively. All mice were kept until their natural death. Statistical analyses show that the life spans of the both sexes irradiated at 20 mGy/day (p<0.0001) and of females irradiated at 1 mGy/day (p<0.05) were significantly shorter than those of the control group. There was no evidence of lengthened life span in mice continuously exposed to very low dose-rates of gama-rays. Pathodological examinations showed that the most frequently observed lethal neoplasms in males were malignant lymphomas, liver, lung, and soft tissue neoplasms, whereas, in females, malignant lymphomas and soft tissue neoplasms were common. No significant difference in the causes of death and mortality rates between groups. Hematopoietic neoplasms (malignant lymphoma and myeloid leukemia), liver, lung and soft tissue neoplasms, showed a tendency to appear at a younger age in both sexes irradiated at 20 mGy/day. Experiment 2: effects on the progeny of chronic low dose-rate gamma-ray irradiated SPF mice: preliminary study. No significant difference was observed between non-irradiated group and irradiated group with regards to litter size, sex ratio and causes of death in F1 and F2 mice. (author)

  4. Comparative response of dogs and monkeys to sublethal acute and continuous low dose-rate gamma-ray exposure

    International Nuclear Information System (INIS)

    Spalding, J.F.; Holland, L.M.; Johnson, O.S.; LaBauve, P.M.; London, J.E.; Prine, J.R.; Vigil, E.A.

    1977-02-01

    Monkeys (Macaca mulatta) and dogs (beagle) were given thirteen 100-rad gamma-ray doses at 28-day intervals. The comparative response (injury and recovery) of the hematopoietic system of the two species was observed at 7-day intervals during the exposure regime. At 84 days after the thirteenth gamma-ray dose, the 1300-rad conditioned and control dogs and monkeys were challenged continuously with 35 R/day until death to determine the amount of radiation-induced injury remaining in conditioned animals as a reduction in mean survival time. Dogs (50 percent) and monkeys (8 percent) died from injury incurred during the conditioning exposures. Thus, the comparative response of dogs and monkeys to dose protraction by acute dose fractionation was similar to what might be expected from a single acute dose. Mean survival times for nonconditioned dogs and monkeys during continuous exposure at 35 R/day were the same (approximately 1400 h). Thus, hematopoietic response of the two species by this method of dose protraction was not significantly different. Mean survival times of conditioned dogs and monkeys during the continuous 35 R/day gamma-ray challenge exposure were greater than for their control counterparts. Thus, the long-term radiation-induced injury was not measurable by this method. Conditioning doses of more than four times the acute LD 50 - 30 in dogs and approximately two times that of monkeys served only to increase both mean survival time and variance in a gamma-ray stress environment with a dose rate of 35 R/day

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

    CERN Document Server

    Marel, J V D

    2001-01-01

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

  6. Spatial variation of natural terrestrial gamma-ray dose rates in Brunei

    International Nuclear Information System (INIS)

    Hu, S.J.; Lai, K.K.; Manato, S.; Kodaira, K.

    1998-01-01

    A carbon survey of natural terrestrial gamma-rat dose rates along the main roads of the western part of Brunei Darussalam was carried out using two portable type 1.5 φ x 4 NaI(TI) and 1 φ x 2 NaI(TI) scintillation counters. A series of semicontinuous count rates measurements were performed inside a moving vehicle. This yielded equal-distance data which were analysed statistically to obtain the spatial variation of the natural terrestrial gamma-ray dose rates. The equal-distance data of dose rates were obtained by correcting for shielding effect of the car. The thickness of the pavement and the contribution from the pavement material were estimated from a correlation curve between the dose rates measured on pavements and on the nearby soils. A spectral analysis of the equal-distance data enabled us to clarify the structure of the spatial variation in dose rates. The data could be reasonably smoothened by removing the random noise components in a higher wave number region. (author). 6 refs., 7 figs., 1 tab

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

    International Nuclear Information System (INIS)

    Tabosa, Jose Nildo; Gomes, Roberto Vicente; Reis, Odemar Vicente dos; Colaco, Waldeciro

    2004-01-01

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

  8. Effect of dose of gamma-rays and ethylmethane sulphonate on the germination and survival of induced mutations in pigeonpea

    Energy Technology Data Exchange (ETDEWEB)

    Premsekar, S [Central Inst. for Cotton Research, Coimbatore (India). Regional Station; Appadurai, R [Tamil Nadu Agricultural Univ., Coimbatore (India)

    1981-06-01

    The LD/sub 50/ values for germination and survival of the induced mutants (M/sub 1/) of pigeonpea (Cajanus cajan (Linn.) Millsp.) were attained with 20 and 15 krad when gamma-rays were used, and 30 and 40 mM concentration when EMS was used. In the combination treatments the half-kill dose for germination and survival was reached even at the low dose combination of 5 krad gamma-ray + 20 mM EMS. Higher doses resulted in lower pollen and seed fertility. The sterility was much enhanced in the combined treatments. The number of pods, seed yield and weight of seeds could be stimulated with 10 and 15 krad doses of gamma-rays and 20 mM of EMS. In combination treatments such a stimulatory effect was noticed in seed weight only.

  9. Application of airborne gamma spectrometric survey data to estimating terrestrial gamma-ray dose rates: An example in California

    International Nuclear Information System (INIS)

    Wollenberg, H.A.; Revzan, K.L.; Smith, A.R.

    1992-01-01

    The authors examine the applicability of radioelement data from the National Aerial Radiometric Reconnaissance (NARR) to estimate terrestrial gamma-ray absorbed dose rates, by comparing dose rates calculated from aeroradiometric surveys of U, Th, and K concentrations in 1 x 2 degree quadrangles with dose rates calculated from a radiogeologic data base and the distribution of lithologies in California. Gamma-ray dose rates increase generally from north to south following lithological trends. Low values of 25--30 nG/h occur in the northernmost quadrangles where low-radioactivity basaltic and ultramafic rocks predominate. Dose rates then increase southward due to the preponderance of clastic sediments and basic volcanics of the Franciscan Formation and Sierran metamorphics in north central and central California, and to increasing exposure southward of the Sierra Nevada batholith, Tertiary marine sedimentary rocks, intermediate to acidic volcanics, and granitic rocks of the Coast Ranges. High values, to 100 nGy/h occur in southeastern California, due primarily to the presence of high-radioactivity Precambrian and pre Cenozoic metamorphic rocks. Lithologic-based estimates of mean dose rates in the quadrangles generally match those from aeroradiometric data, with statewide means of 63 and 60 nGy/h, respectively. These are intermediate between a population-weighted global average of 51 nGy/h and a weighted continental average of 70 nGy/h, based on the global distribution of rock types. The concurrence of lithologically- and aeroradiometrically- determined dose rates in California, with its varied geology and topography encompassing settings representative of the continents, indicates that the NARR data are applicable to estimates of terrestrial absorbed dose rates from natural gamma emitters

  10. Near-term and late biological effects of acute and low-dose-rate continuous gamma-ray exposure in dogs and monkeys

    International Nuclear Information System (INIS)

    Spalding, J.F.; Holland, L.M.

    1979-07-01

    Monkeys (Macaca mulatta) and dogs (beagle) were given thirteen 100-rad gamma-ray doses at 28-day intervals. The comparative response (inury and recovery) of the hematopoietic system of the two species was observed at 7-day intervals during the exposure regime. At 84 days after the thirteenth gamma-ray dose, the 1300-rad conditioned and control dogs and monkeys were challenged continuously with gamma rays at 35 r/day until death to determine the amount of radiation-induced injry remaining in conditioned animals as a reduction in mean survival time. Dogs (50%) and monkeys (8%) died from injury incurred during conditioning exposures. Thus, the comparative response (in terms of lethality) of dogs and monkeys to dose protraction by acute dose fractionation was similar to what we would expect from a single acute dose. The mean survival times for nonconditioned dogs and monkeys during continuous exposure at 35 R/day were the same (approx. 1400 h). Thus, the hematopoietic response of the two species by this method of dose protraction was not significantly different. Mean survival times of conditioned dogs and monkeys during the continuous 35-R/day gamma-ray challenge exposure were greater (significant in dogs but not in monkeys) than for their control counterparts. Thus, long-term radiation-induced injury was not measurable by this method. Conditioning doses of more than 4 times the acute LD 50 30 in dogs and approximately 2 times that in monkeys served only to increase both mean survival time and variance in a gamma-ray stress environment with a dose rate of 35 Rat/day

  11. Effect of low doses gamma irradiation on seed, bulblets and bulbs of onion

    International Nuclear Information System (INIS)

    Al-Oudat, Mohammad

    1991-10-01

    Presowing seed irradiation has been reported as a useful application of radiation in agriculture to stimulate growth and increase the yield of certain crops. To the best of our knowledge the feasibility of this treatment has not yet been tested on onion in Syria. The effect of low doses gamma irradiation on onion seeds, bulblets and bulbs of two local varieties, red and white, was studied during three consecutive seasons (1986 - 1988). Air dried seeds were irradiated by gamma rays from 137 Cs source. Five, 10, 15, 20 and 30 GY, were applied at dose rate of 9.8 Gy/min. The irradiation of onion bulblets and bulbs were carried out with gamma-rays from 60 Co source at a dose rate of 0.5 Gy/min. using 1, 2, 3, 4 and 5 Gy. Within 7 - 10 days after irradiation, both controlled and irradiated seeds, bulblets and bulbs were sown in the field in complete randomized block design with 4 replicates. Irradiation of seeds with doses of 5, 10 and 15 Gy led to highly significant increases in bulblets yield in the three seasons. The increases ranged from 14.5 to 22.1 for red variety and from 16.2 to 22.3 for white variety. The irradiation of bulblets with 1 and 2 Gy increase significantly the yield of bulbs by 21.6 - 26.0% for red variety and 21.6 - 24.4% for white variety. A considerable increase in seed yield was obtained after irradiation of bulbs with 1 and 2 Gy doses. The average increment was about 21.0% for both varieties. Large scale application were performed in 1989 and 1990 using doses of 10 Gy for seeds and 1 Gy for bulblets and bulbs. A considerable increase in the yield was obtained. The average percentage increment was 16.9% and 23.3% for seeds, 18.6 and 20.9% for bulblets, 24.8 and 27.3% for bulbs, for red and white varieties respectively. Therefore, presowing irradiation of seeds, bulblets and bulbs of onion with low doses of gamma-rays (5 - 15 Gy for seeds and 1 - 2 Gy for bulblets and bulbs) can be of practical application resulting in improvement of yield of

  12. Environmental gamma-ray dose measurements with thermoluminescence dosemeters (TLD) and environmental radiation characteristics

    International Nuclear Information System (INIS)

    Kanematsu, Seiko

    1999-01-01

    It is important to evaluate environmental gamma-ray exposure both at work and home in order to assess people's collective dosages. Environmental gamma radiation was measured for air-absorbed dose with a thermoluminescence dosemeter at various points in the workplace and Ningyotoge, and workplace radiation characteristics were analyzed. From the results, the public dose due to gamma rays generated artificially was assessed to be sufficiently lower than the annual limit. For indoor environments of the workplace, the maximum dosage rate among measured values was 97 nGy/h and the minimum value was 70 nGy/h, the average over one year was 83 nGy/h. The average annual outdoor dosage for a year was 82 nGy/ h. In Ningyotoge, the maximum was 103 nGy/h, minimum 60 nGy/h, and average 88 nGy/h. These values depend on the nature of the soil and weather factors, showing higher values in the summer than in the winter in the workplace. There was no significant difference in the dosage rate in houses and the workplace. (author)

  13. Tumor induction in mice after local irradiation with single doses of either carbon-ion beams or gamma rays.

    Science.gov (United States)

    Ando, Koichi; Koike, Sachiko; Ohmachi, Yasushi; Ando, Yutaka; Kobashi, Gen

    2014-12-01

    To determine the dose-dependent relative biological effectiveness (RBE) for tumor prevalence in mice receiving single localized doses to their right leg of either carbon ions (15, 45 or 75 keV/μm) or 137Cs gamma rays. A total of 1647 female C3H mice were irradiated to their hind legs with a localized dose of either reference gamma rays or 15, 45 or 75 keV/μm carbon-ion beams. Irradiated mice were evaluated for tumors twice a month during their three-year life span, and the dimensions of any tumors found were measured with a caliper. The tumor induction frequency was calculated by Kaplan-Meier analysis. The incidence of tumors from 50 Gy of 45 keV/μm carbon ions was marginally higher than those from 50 Gy of gamma rays. However, 60 Gy of 15 keV/μm carbon ions induced significantly fewer tumors than did gamma rays. RBE values of 0.87 + 0.12, 1.29 + 0.08 or 2.06 + 0.39 for lifetime tumorigenesis were calculated for 15, 45 or 75 keV/μm carbon-ion beams, respectively. Fibrosarcoma predominated, with no Linear Energy Transfer (LET)-dependent differences in the tumor histology. Experiments measuring the late effect of leg skin shrinkage suggested that the carcinogenic damage of 15 keV/μm carbon ions would be less than that of gamma rays. We conclude that patients receiving radiation doses to their normal tissues would face less risk of secondary tumor induction by carbon ions of intermediate LET values compared to equivalent doses of photons.

  14. Determination of Proton dose distal fall-off location by detecting right-angled prompt gamma rays

    International Nuclear Information System (INIS)

    Seo, Kyu Seok

    2006-02-01

    The proton beam has a unique advantage over the electron and photon beams in that it can give very high radiation dose to the tumor volume while effectively sparing the neighboring healthy tissue and organs. The number of proton therapy facility is very rapidly increasing in the world. And now the 230 MeV cyclotron facility for proton therapy is constructing at National Cancer Center, this facility until 2006. The distal fall-off location of proton beam is simply calculated by analytical method, but this method has many uncertain when anatomical structure is very complicated. It is very important to know the exact position of the proton beam distal fall-off, or beam range, in the patient's body for both the safety of the patient and the effectiveness of the treatment itself. In 2003, Stichelbaut and Jongen reported the possibility of using the right-angled prompt gamma rays, which are emitted at 90 .deg. from the incident proton beam direction, to determine the position of the proton beam distal fall-off. They studied the interactions of the protons and other secondary particles in a water phantom and concluded that there is a correlation between the position of the distal fall-off and the distribution of the right-angled prompt gamma rays. We have recently designed a prompt gamma scanning system to measure the proton range in situ by using Monte Carlo technique employing MCNPX, FLUKA, and Sabrina TM . The prompt gamma scanning system was designed to measure only the right-angled prompt gamma rays passing through a narrow collimation hole in order to correlate the position with the dose distribution. The collimation part of the scanning system, which has been constructed to measure the gamma rays at 70 MeV of proton energy, is made of a set of paraffin, boron carbide, and lead layers to shield the high-energy neutrons and secondary photons. After the different proton energies and SOBP beam widths are irradiated at the water phantom. we detected prompt gamma at 5 cm

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

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jai Wan; Jeong, Kyung Min [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

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

  16. [Induction of glutathione and activation of immune functions by low-dose, whole-body irradiation with gamma-rays].

    Science.gov (United States)

    Kojima, Shuji

    2006-10-01

    We first examined the relation between the induction of glutathione and immune functions in mice after low-dose gamma-ray irradiation. Thereafter, inhibition of tumor growth by radiation was confirmed in Ehrlich solid tumor (EST)-bearing mice. The total glutathione level of the splenocytes transiently increased soon after irradiation and reached a maximum at around 4 h postirradiation. Thereafter, the level reverted to the 0 h value by 24 h postirradiation. A significantly high splenocyte proliferative response was also recognized 4 h postirradiation. Natural killer (NK) activity was also increased significantly in a similar manner. The time at which the response reached the maximum coincided well with that of maximum total glutathione levels of the splenocytes in the gamma-ray-irradiated mice. Reduced glutathione exogenously added to splenocytes obtained from normal mice enhanced the proliferative response and NK activity in a dose-dependent manner. The inhibitory effects of radiation on tumor growth was then examined in EST-bearing mice. Repeated low-dose irradiation (0.5 Gy, four times, before and within an early time after inoculation) significantly delayed the tumor growth. Finally, the effect of single low-dose (0.5 Gy), whole-body gamma-ray irradiation on immune balance was examined to elucidate the mechanism underlying the antitumor immunity. The percentage of B cells in blood lymphocytes was selectively decreased after radiation, concomitant with an increase in that of the helper T cell population. The IFN-gamma level in splenocyte culture prepared from EST-bearing mice was significantly increased 48 h after radiation, although the level of IL-4 was unchanged. IL-12 secretion from macrophages was also enhanced by radiation. These results suggest that low-dose gamma-rays induce Th1 polarization and enhance the activities of tumoricidal effector cells, leading to an inhibition of tumor growth.

  17. Dose Distribution Calculation Using MCNPX Code in the Gamma-ray Irradiation Cell

    International Nuclear Information System (INIS)

    Kim, Yong Ho

    1991-02-01

    60 Co-gamma irradiators have long been used for foods sterilization, plant mutation and development of radio-protective agents, radio-sensitizers and other purposes. The Applied Radiological Science Research Institute of Cheju National University has a multipurpose gamma irradiation facility loaded with a MDS Nordin standard 60 Co source (C188), of which the initial activity was 400 TBq (10,800 Ci) on February 19, 2004. This panoramic gamma irradiator is designed to irradiate in all directions various samples such as plants, cultured cells and mice to administer given radiation doses. In order to give accurate doses to irradiation samples, appropriate methods of evaluating, both by calculation and measurement, the radiation doses delivered to the samples should be set up. Computational models have been developed to evaluate the radiation dose distributions inside the irradiation chamber and the radiation doses delivered to typical biolological samples which are frequently irradiated in the facility. The computational models are based on using the MCNPX code. The horizontal and vertical dose distributions has been calculated inside the irradiation chamber and compared the calculated results with measured data obtained with radiation dosimeters to verify the computational models. The radiation dosimeters employed are a Famer's type ion chamber and MOSFET dosimeters. Radiation doses were calculated by computational models, which were delivered to cultured cell samples contained in test tubes and to a mouse fixed in a irradiation cage, and compared the calculated results with the measured data. The computation models are also tested to see if they can accurately simulate the case where a thick lead shield is placed between the source and detector. Three tally options of the MCNPX code, F4, F5 and F6, are alternately used to see which option produces optimum results. The computation models are also used to calculate gamma ray energy spectra of a BGO scintillator at

  18. Natural gamma-ray spectrometry as a tool for radiation dose and radon hazard modelling

    International Nuclear Information System (INIS)

    Verdoya, M.; Chiozzi, P.; De Felice, P.; Pasquale, V.; Bochiolo, M.; Genovesi, I.

    2009-01-01

    We reviewed the calibration procedures of gamma-ray spectrometry with particular emphasis to factors that affect accuracy, detection limits and background radiation in field measurements for dosimetric and radon potential mapping. Gamma-ray spectra were acquired in western Liguria (Italy). The energy windows investigated are centred on the photopeaks of 214 Bi (1.76 MeV), 208 Tl (2.62 MeV) and 40 K (1.46 MeV). The inferred absorbed dose rate and the radon flux are estimated to be lower than 60 nGy h -1 and 22 Bq m -2 h -1 , respectively.

  19. Intensity of the absorbing dose of the gamma rays in the air of Krusevac during and after nuclear accident in Chernobil

    International Nuclear Information System (INIS)

    Fortuna, D.

    1997-01-01

    In this paper are compared overage daily values of the intensity of the absorbing doses of the gamma rays in the air of Krusevac, during and after nuclear accident in Cernobil. Average daily values of intensity of the absorbing doses of gamma rays in the air of Krusevac, immediately after nuclear accident in Cernobil were, three to seven time higher than of the average daily values of the natural rays. (author)

  20. Apparatus for gamma ray radiography

    International Nuclear Information System (INIS)

    Kobayashi, Masatoshi; Enomoto, Shigemasa; Oga, Hiroshi

    1979-01-01

    This is the standard of Japan Non-Destructive Inspection Society, NDIS 1101-79, which stipulates on the design, construction and testing method of the apparatuses for gamma ray radiography used for taking industrial radiograms. The gamma ray apparatuses stipulated in this standard are those containing sealed radioactive isotopes exceeding 100 μCi, which emit gamma ray. The gamma ray apparatuses are classified into three groups according to their movability. The general design conditions, the irradiation dose rate and the sealed radiation sources for the gamma ray apparatuses are stipulated. The construction of the gamma ray apparatuses must be in accordance with the notification No. 52 of the Ministry of Labor, and safety devices and collimators must be equipped. The main bodies of the gamma ray apparatuses must pass the vibration test, penetration test, impact test and shielding efficiency test. The method of each test is described. The attached equipments must be also tested. The tests according to this standard are carried out by the makers of the apparatuses. The test records must be made when the apparatuses have passed the tests, and the test certificates are attached. The limit of guarantee by the endurance test must be clearly shown. The items to be shown on the apparatuses are stipulated. (Kako, I.)

  1. Airborne and total gamma absorbed dose rates at Patiala - India

    International Nuclear Information System (INIS)

    Tesfaye, Tilahun; Sahota, H.S.; Singh, K.

    1999-01-01

    The external gamma absorbed dose rate due to gamma rays originating from gamma emitting aerosols in air, is compared with the total external gamma absorbed dose rate at the Physics Department of Punjabi University, Patiala. It has been found out that the contribution, to the total external gamma absorbed dose rate, of radionuclides on particulate matter suspended in air is about 20% of the overall gamma absorbed dose rate. (author)

  2. Intercomparison of personnel dosimetry for thermal neutron dose equivalent in neutron and gamma-ray mixed fields

    International Nuclear Information System (INIS)

    Ogawa, Yoshihiro

    1985-01-01

    In order to consider the problems concerned with personnel dosimetry using film badges and TLDs, an intercomparison of personnel dosimetry, especially dose equivalent responses of personnel dosimeters to thermal neutron, was carried out in five different neutron and gamma-ray mixed fields at KUR and UTR-KINKI from the practical point of view. For the estimation of thermal neutron dose equivalent, it may be concluded that each personnel dosimeter has good performances in the precision, that is, the standard deviations in the measured values by individual dosimeter were within 24 %, and the dose equivalent responses to thermal neutron were almost independent on cadmium ratio and gamma-ray contamination. However, the relative thermal neutron dose equivalent of individual dosimeter normalized to the ICRP recommended value varied considerably and a difference of about 4 times was observed among the dosimeters. From the results obtained, it is suggested that the standardization of calibration factors and procedures is required from the practical point of radiation protection and safety. (author)

  3. Induced mitotic gynogenesis in common carp (Cyprinus carpio L.), optimizing irradiation dose of X- and gamma-ray

    International Nuclear Information System (INIS)

    Yousefian, M.; Amirinia, C.; Bercsenyi, M.; Horvath, L.

    1997-01-01

    Mitotic gynogenesis was induced in common carp, Cyprinus carpio L., in hatchery and laboratory conditions, using 60Co gamma-ray and X-ray for inactivation of sperm DNA and a subsequent heat shock for inducing endomitosis. The parameter examined was the dose of irradiation in the range of 70-140 Krad. Carp spermatozoa irradiated by 70-100 Krad doses showed higher motility and fertilization ability than the ones irradiated by 110-140 Krad. Sperm treated with doses of 70-90 Krad showed the same fertility rate, but lower survival rate at embryo stage compared with 100 Krad. The shock temperature and duration applied in these experiments for restoration of diploidy level were 40 degrees C plus/minus 0.1 and 2 min., respectively. The highest frequency of mitotic gynogenetic larvae was achieved by 100 Krad 60Co gamma ray at 34 min. after fertilization, - up to 12.2 percent (at 23 degrees C incubating temperature)

  4. A simple method for conversion of airborne gamma-ray spectra to ground level doses

    DEFF Research Database (Denmark)

    Korsbech, Uffe C C; Bargholz, Kim

    1996-01-01

    A new and simple method for conversion of airborne NaI(Tl) gamma-ray spectra to dose rates at ground level has been developed. By weighting the channel count rates with the channel numbers a spectrum dose index (SDI) is calculated for each spectrum. Ground level dose rates then are determined...... by multiplying the SDI by an altitude dependent conversion factor. The conversion factors are determined from spectra based on Monte Carlo calculations. The results are compared with measurements in a laboratory calibration set-up. IT-NT-27. June 1996. 27 p....

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1981-08-01

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

  6. Radiation inactivation of Paenibacillus larvae and sterilization of American Foul Brood (AFB) infected hives using Co-60 gamma rays

    International Nuclear Information System (INIS)

    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.

    2011-01-01

    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 60 Co source. Surviving spores were counted and used to estimate the decimal reduction (D 10 ) value. A dose of 0.2 kGy was sufficient to inactivate 90% of the total recoverable spores from an initial count of 10 5 -9x10 3 spores per glass plate. The sterilizing effect of high doses of gamma radiation on the spores of P. larvae in infected hives was determined. In this study, a minimum dose (D min ) of 15 kGy was tested. Beehives with sub-clinical infections of AFB were irradiated and examined for sterility. All the materials were found to be free of P. larvae indicating its susceptibility to γ-rays. After irradiation, there were no visible changes in the physical appearance of the hives' body, wax and frames. Thus, a dose of 15 kGy is effective enough for sterilization of AFB-infected materials. - Highlights: → We characterized Paenibacillus larvae and determined its radiation sensitivity. → We investigated the effectiveness of gamma rays in inactivating P. larvae. → Gamma radiation inactivates P. larvae. → 15 kGy is effective for the sterilization of P. larvae-infected hives. → Irradiation produces no visible changes in the hives' body, waxes and frames.

  7. Comparative effectiveness of gamma-rays and electron beams in food irradiation

    International Nuclear Information System (INIS)

    Hayashi, Toru

    1991-01-01

    Ionizing radiations which can be used for the treatment of foods are gamma-rays from Co-60 and Cs-137, accelerated electrons from a machine at an energy of 10 MeV or lower and X-rays from a machine at an energy of 5 MeV or lower. The Joint FAO/IAEA/WHO Expert Committee on the Wholesomeness of Irradiated Food held in 1980 concluded that the foods irradiated at overall average doses up to 10 kGy with the radiation listed above are wholesome for human consumption. While most of the commercial food irradiations are conducted with gamma-rays from Co-60, accelerated electrons are increasingly utilized for treating foods. An important difference between gamma-rays and accelerated electrons is the penetration capacity in materials. The penetration capacity of gamma-rays is much higher than that of accelerated electrons. Another important difference is the dose rate. The dose rates of gamma-rays from commercial Co-60 sources are 1-100 Gy/min, while those of electron beams from electron accelerators are 10 3 -10 6 Gy/s. Ideally a comparison of the effect of different types of ionizing radiation should be carried out at the same dose rate but this has been difficult due to the design of irradiators. It is very difficult to draw a definite conclusion on the difference in the effectiveness in food irradiation between gamma-rays and electron beams based on published data. This chapter deals with as many reports as possible on the comparative effectiveness of gamma-rays and electron beams and on the effect of dose rate on chemical reactions and living organisms, whether or not they demonstrate any dependency of the effect of irradiation on dose rate and type of radiation. (author)

  8. Calculating gamma dose factors for hot particle exposures

    International Nuclear Information System (INIS)

    Murphy, P.

    1990-01-01

    For hot particle exposures to the skin, the beta component of radiation delivers the majority of the dose. However, in order to fully demonstrate regulatory compliance, licenses must ordinarily provide reasonable bases for assuming that both the gamma component of the skin dose and the whole body doses are negligible. While beta dose factors are commonly available in the literature, gamma dose factors are not. This paper describes in detail a method by which gamma skin dose factors may be calculated using the Specific Gamma-ray Constant, even if the particle is not located directly on the skin. Two common hot particle exposure geometries are considered: first, a single square centimeter of skin lying at density thickness of 7 mg/cm 2 and then at 1000 mg/cm 2 . A table provides example gamma dose factors for a number of isotopes encountered at power reactors

  9. Very high-energy gamma rays from gamma-ray bursts.

    Science.gov (United States)

    Chadwick, Paula M

    2007-05-15

    Very high-energy (VHE) gamma-ray astronomy has undergone a transformation in the last few years, with telescopes of unprecedented sensitivity having greatly expanded the source catalogue. Such progress makes the detection of a gamma-ray burst at the highest energies much more likely than previously. This paper describes the facilities currently operating and their chances for detecting gamma-ray bursts, and reviews predictions for VHE gamma-ray emission from gamma-ray bursts. Results to date are summarized.

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

    International Nuclear Information System (INIS)

    Fukuda, Kyue

    1980-01-01

    Specimens of muscovite mica were first exposed to fission fragments and then to various gamma-ray fields from a 60 Co source ranging from 1.9 x 10 3 to 1.6 x 10 4 Mrad dose. The results show that the average etched width of fission-fragment tracks decreases with increasing gamma-ray dose. Shallow pits were observed in etched specimens when the gamma-ray dose exceeded 5 x 10 3 Mrad. Numerous shallow etch pits caused by the gamma-ray irradiation interfered with the observation of fission tracks in the specimens. No shallow etch pits were observed in the specimen annealed for 100 min at 600 0 C before the gamma-ray irradiation. Pre-annealing extends the ''safety limits'' of gamma background below which muscovite mica can be used to observe fission tracks without any gamma-ray interference. Gamma-ray and electron irradiation caused significant increase of the resistance to thermal decomposition of muscovite mica. The resistance increased markedly in the dose range from 5 x 10 3 to 8 x 10 3 Mrad. These phenomena suggest the use of mica to assess radiation doses of gamma rays and electrons up to several thousand megarads. (author)

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

    International Nuclear Information System (INIS)

    Grahn, D.; Duggal, K.; Lombard, L.S.

    1985-01-01

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

  12. Gamma-ray dose rate in air on the subway lines in Tokyo metropolitan area

    International Nuclear Information System (INIS)

    Ogawa, Masayuki; Hosoda, Masahiro; Ogashiwa, Susumu; Fukushi, Masahiro

    2008-01-01

    Measurements of gamma-ray dose rates in air were performed on 12 subway lines in Tokyo from the perspective of health physics, because the subways are commonly used for commuting in the Tokyo metropolitan area. The results showed that the maximum dose rate (36.5 nGy/h) was 1.6 times higher than that of the minimum one (23.3 nGy/h), and that the dose rate in the subway car was 33% lower than the outside. Also the results strongly suggested that the dose rates depend on the concentration of natural radionuclide around the subway lines and the platform structures rather than the depth. (author)

  13. Avoidance behaviour and anxiety in rats irradiated with a sublethal dose of gamma-rays.

    Science.gov (United States)

    Tomášová, Lenka; Smajda, B; Bona, M

    2011-12-01

    The aim of this study was to assess, whether a sublethal dose of gamma-rays will influence the avoidance behaviour and anxiety in rats and whether the response to radiation depends on time of day of its application. Adult male Wistar rats were tested in elevated plus-maze, in hot plate test and in the light/dark box in 4 regular intervals during a day. After two weeks the animals were irradiated with a whole-body dose 6 Gy of gamma-rays. One day after irradiation the animals were repeatedly tested in the same way, as before irradiation. In the plus-maze test an increased level of anxiety was established. The irradiation significantly decreased the locomotor activity of rats, but the extent of exploratory and comfortable behaviour were not altered. After irradiation, an elevated aversion to the thermal stimulus was observed in the hot plate test. The effects of radiation were more pronounced in the light period of the day, than in the dark one. No significant differences in aversion to light were detected after irradiation. The obtained results indicate, that sublethal doses of ionizing radiation can markedly influence the reactivity of animals to adverse stimuli, their motoric activity and emotional status, as well.

  14. Spectrum-to-dose conversion operator value function of a Ge(Li) in-situ environmental gamma-ray spectrometer

    International Nuclear Information System (INIS)

    Terada, Hiromi; Sakai, Eiji; Katagiri, Masaki

    1976-05-01

    A spectrum-to-dose conversion operator value function was obtained for a 73cm 3 closed-end coaxial Ge(Li) in-situ environmental gamma-ray spectrometer; factors influencing the function are considered. (auth.)

  15. Inactive Doses and Protein Concentration of Gamma Irradiated Yersinia Enterocolitica

    International Nuclear Information System (INIS)

    Irawan Sugoro; Sandra Hermanto

    2009-01-01

    Yersinia enterocolitica is one of bacteria which cause coliform mastitis in dairy cows. The bacteria could be inactivated by gamma irradiation as inactivated vaccine candidate. The experiment has been conducted to determine the inactive doses and the protein concentration of Yersinia enterocolitica Y3 which has been irradiated by gamma rays. The cells cultures were irradiated by gamma rays with doses of 0, 100, 200, 400, 600, 800, 1.000 and 1.500 Gy (doses rate was 1089,59 Gy/hours). The inactive dose was determined by the drop test method and the protein concentration of cells were determined by Lowry method. The results showed that the inactive doses occurred on 800 – 1500 Gy. The different irradiation doses of cell cultures showed the effect of gamma irradiation on the protein concentration that was random and has a significant effect on the protein concentration. (author)

  16. Radiation inactivation of Paenibacillus larvae and sterilization of American Foul Brood (AFB) infected hives using Co-60 gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    De Guzman, Zenaida M. [Microbiological Research and Service Laboratory, Atomic Research Division, Philippine Nuclear Research Institute, Diliman, Quezon City (Philippines); Cervancia, Cleofas R. [Institute of Biological Sciences, College of Arts and Sciences, University of the Philippines, Los Banos, Laguna (Philippines); Dimasuay, Kris Genelyn B.; Tolentino, Mitos M.; Abrera, Gina B.; Cobar, Ma. Lucia C. [Microbiological Research and Service Laboratory, Atomic Research Division, Philippine Nuclear Research Institute, Diliman, Quezon City (Philippines); Fajardo, Alejandro C.; Sabino, Noel G.; Manila-Fajardo, Analinda C. [Institute of Biological Sciences, College of Arts and Sciences, University of the Philippines, Los Banos, Laguna (Philippines); Feliciano, Chitho P., E-mail: cpfeliciano@pnri.dost.gov.ph [Microbiological Research and Service Laboratory, Atomic Research Division, Philippine Nuclear Research Institute, Diliman, Quezon City (Philippines); Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City (Philippines)

    2011-10-15

    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 {sup 60}Co source. Surviving spores were counted and used to estimate the decimal reduction (D{sub 10}) value. A dose of 0.2 kGy was sufficient to inactivate 90% of the total recoverable spores from an initial count of 10{sup 5}-9x10{sup 3} 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{sub 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 {gamma}-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. - Highlights: > We characterized Paenibacillus larvae and determined its radiation sensitivity. > We investigated the effectiveness of gamma rays in inactivating P. larvae. > Gamma radiation inactivates P. larvae. > 15 kGy is effective for the sterilization of P. larvae-infected hives. > Irradiation produces no visible changes in the hives' body, waxes and frames.

  17. Dose-response relationship of {gamma}-H2AX foci induction in human lymphocytes after X-rays exposure

    Energy Technology Data Exchange (ETDEWEB)

    Mandina, Tania [Centro de Proteccion e Higiene de las Radiaciones, Calle 20 No. 4113 e/41y 47 Miramar, AP 6195 C. Habana (Cuba); Roch-Lefevre, Sandrine H.; Voisin, Pascale [Institut de Radioprotection et de Surete Nucleaire (IRSN), DRPH, SRBE, LDB, BP17, 92262 Fontenay-aux-Roses (France); Gonzalez, Jorge E.; Lamadrid, Ana I.; Romero, Ivonne [Centro de Proteccion e Higiene de las Radiaciones, Calle 20 No. 4113 e/41y 47 Miramar, AP 6195 C. Habana (Cuba); Garcia, Omar, E-mail: omar@cphr.edu.cu [Centro de Proteccion e Higiene de las Radiaciones, Calle 20 No. 4113 e/41y 47 Miramar, AP 6195 C. Habana (Cuba); Voisin, Philippe; Roy, Laurence [Institut de Radioprotection et de Surete Nucleaire (IRSN), DRPH, SRBE, LDB, BP17, 92262 Fontenay-aux-Roses (France)

    2011-09-15

    Biological dosimeters are recommended for dose estimation in case of human overexposure to ionising radiation. Rapid measurement of {gamma}-H2AX foci as a marker of DNA double-strand breaks (DSB) induction has been recently tested with this purpose. Here we reported a dose-response relationship after X-ray irradiation at different times post-exposure. Blood samples were obtained from several healthy donors and exposed to doses between 0 and 2 Gy. After irradiation, blood samples were incubated at 37 deg. C during 0.5 h, 5 h, and 8 h. Scoring of cells and {gamma}-H2AX foci was performed by software. The dose-response curves for different incubation times were as follows: Y{sub (0.5h)} = 11.66D + 0.15 (R{sup 2} = 0.99), Y{sub (5h)} = 2.44D + 0.15 (R{sup 2} = 0.99), Y{sub (8h)} = 1.57D + 0.22 (R{sup 2} = 0.99). At 0.5 h post-exposure, the dose-response relationship for X-irradiated lymphocytes was similar to the one obtained after gamma-irradiation using the same protocol. On the other hand, the results were not similar after 8 h due to different kinetics after gamma- and X-irradiation. Our results confirm the possibilities of using {gamma}-H2AX foci method for dose estimation in a period from 0.5 h up to 8 h post X-irradiation and support the hypothesis of differences in {gamma}-H2AX foci kinetics after gamma- and X-irradiation in vitro.

  18. Development of Monte Carlo decay gamma-ray transport calculation system

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Satoshi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Kawasaki, Nobuo [Fujitsu Ltd., Tokyo (Japan); Kume, Etsuo [Japan Atomic Energy Research Inst., Center for Promotion of Computational Science and Engineering, Tokai, Ibaraki (Japan)

    2001-06-01

    In the DT fusion reactor, it is critical concern to evaluate the decay gamma-ray biological dose rates after the reactor shutdown exactly. In order to evaluate the decay gamma-ray biological dose rates exactly, three dimensional Monte Carlo decay gamma-ray transport calculation system have been developed by connecting the three dimensional Monte Carlo particle transport calculation code and the induced activity calculation code. The developed calculation system consists of the following four functions. (1) The operational neutron flux distribution is calculated by the three dimensional Monte Carlo particle transport calculation code. (2) The induced activities are calculated by the induced activity calculation code. (3) The decay gamma-ray source distribution is obtained from the induced activities. (4) The decay gamma-rays are generated by using the decay gamma-ray source distribution, and the decay gamma-ray transport calculation is conducted by the three dimensional Monte Carlo particle transport calculation code. In order to reduce the calculation time drastically, a biasing system for the decay gamma-ray source distribution has been developed, and the function is also included in the present system. In this paper, the outline and the detail of the system, and the execution example are reported. The evaluation for the effect of the biasing system is also reported. (author)

  19. Secondary gamma-ray data for shielding calculation

    International Nuclear Information System (INIS)

    Miyasaka, Sunichi

    1979-01-01

    In deep penetration transport calculations, the integral design parameters is determined mainly by secondary particles which are produced by interactions of the primary radiation with materials. The shield thickness and the biological dose rate at a given point of a bulk shield are determined from the contribution from secondary gamma rays. The heat generation and the radiation damage in the structural and shield materials depend strongly on the secondary gamma rays. In this paper, the status of the secondary gamma ray data and its further problems are described from the viewpoint of shield design. The secondary gamma-ray data in ENDF/B-IV and POPOP4 are also discussed based on the test calculations made for several shield assemblies. (author)

  20. Measurement of the reduction of terrestrial gamma-ray dose rates by the snow cover using TL-dosimeters

    International Nuclear Information System (INIS)

    Sakamoto, Ryuichi; Saito, Kimiaki; Nagaoka, Toshi; Tsutsumi, Masahiro; Moriuchi, Shigeru

    1990-12-01

    The objective of the investigation is to make clear the effect of the snow cover on environmental gamma-ray field. The reduction in the natural terrestrial gamma-ray dose rate due to snow cover was measured by TL-dosimeters. The measurements were performed in autumn before snowfall and in winter from September 1987 through March 1988 in Nagaoka city, Niigata prefecture. The dosimeters were set at four points, both outside and inside of the houses, for three months. The penetration factors (ratios of terrestrial gamma-ray dose accumulated during snow covered period to those during snow free period) were 0.54-0.67 in the open field, and 0.73-0.95 in the houses. According to theoretical calculation by the Monte Carlo method and the published snowfall data, the corresponding penetration factor was estimated at 0.54 in an ideal open field. As a result, the measured penetration factors were larger than calculated one by 24 % at maximum. The variation of dose rate inside houses by the difference of the amount of snow fall has been investigated. In general, though the amount of snow fall changes every year, dose rates inside the house were proved to be affected little by them. And, the optimum value of snow density which adapted for inference of penetration factor was found to be 0.3 g/cm 3 . The penetration factors inferred from snowdepth data for the year distributed between 0.6 and 1.0 in winter from November 1985 through April 1986 in Niigata prefecture. (author)

  1. Effect of low gamma-ray doses and seeding rates on growth, yield and its components as well as seed quality of lentils (lens Culinaries, med.)

    International Nuclear Information System (INIS)

    Dprgham, E.A.

    1999-01-01

    To study the effect of low doses gamma-rays and seeding rates on growth, yield and its components as well as seed quality, two experiments were conducted during 1993/1994 and 1994/1995 seasons. Each experiment included treatments which were the combinations of three levels of seeding rates (45,60 and 75kg/fed.) and four doses of gamma-rays (15, 25,35 and 45(Gy). The effect of interaction between seeding rates and gamma doses on growth characters was not significant whereas there was a tendency for improvement of growth characters by increasing gamma doses up to 45 Gy. Different gamma doses caused marked increase for lintil's yield components except the number of seeds/plant while high seeding rates (60 and 75 Kg/fed) reduced significantly the number of pods/plant and number of seeds/plant. For yield, various gamma doses showed significant increase for seed straw yield as compared to the control. However, seeding rates of 60 and 75 kg/fed increased significantly seed and straw yield as compared with the seeding rate of 45 kg/fed (control)

  2. EBT-P gamma-ray-shielding analysis

    International Nuclear Information System (INIS)

    Gohar, Y.

    1983-01-01

    First, a one-dimensional scoping study was performed for the gamma-ray shield of the ELMO Bumpy Torus proof-of-principle device to define appropriate shielding material and determine the required shielding thickness. The dose-equivalent results are analyzed as a function of the radiation-shield thickness for different shielding options. A sensitivity analysis for the pessimistic case is given. The recommended shielding option based on the performance and cost is discussed. Next, a three-dimensional scoping study for the coil shield was performed for four different shielding options to define the heat load for each component and check the compliance with the design criterion of 10 watts maximum heat load per coil from the gamma-ray sources. Also, a detailed biological-dose survey was performed which included: (a) the dose equivalent inside and outside the building, (b) the dose equivalent from the two mazes of the building, and (c) the skyshine contribution to the dose equivalent

  3. Gamma ray induced chromophore modification of softwood thermomechanical pulp

    International Nuclear Information System (INIS)

    Robert, S.; Daneault, C.; Viel, C.; Lepine, F.

    1992-01-01

    This study focuses on bleaching a softwood (black spruce, balsam fur) thermomechanical pulp with gamma rays. Gamma rays are known for their enormous penetrating power, along with their ionizing properties. They can generate highly energetic radicals capable of oxidizing lignin chromophores. The authors studied the influence of isopropyl alcohol, sodium borohydride, oxygen, hydrogen peroxide, nitrogen dioxide and water along with gamma ray irradiation of the pulps. The authors measured the optimal dose and dose rate, along with the influence of the radical scavengers like oxygen on the bleaching effect of gamma irradiated pulps. They observe various degrees of bleaching of these pulps. Evidence relates this bleaching to the generation of perhydroxyl anions upon irradiation of water. Also, they were able to pinpoint the influence of the dose rate on the rate of formation and disappearance of these perhydroxyl anions and their influence on bleaching kinetics. Stability toward photoyellowing, and photoyellowing's kinetic of papers from these pulps was also studied

  4. Characterization by Monte Carlo of the dose after a glass shield lead for gamma ray; Caracterizacion por Monte Carlo de la dosis tras un blindaje de vidrio de plomo para rayos gamma

    Energy Technology Data Exchange (ETDEWEB)

    Esteve Sanchez, S.; Gil Conde, M.; Contreras Gonzalez, J. L.; Rosado, J.; Pazyi, V.

    2013-07-01

    When a gamma-ray beam crosses the border between two media characterized by atomic number very different is they produce effects on the distribution of doses near the border difficult to predict with simple models. The case of rays gamma affecting a lead glass is particularly interesting for its application to shielding of common use. interested in studying the importance of the residual dose after the shield. (Author)

  5. Approximate techniques for calculating gamma ray dose rates in nuclear power plants

    International Nuclear Information System (INIS)

    Lahti, G.P.

    1986-01-01

    Although today's computers have made three-dimensional discrete ordinates transport codes a virtual reality, there is still a need for approximate techniques for estimating radiation environments. This paper discusses techniques for calculating gamma ray dose rates in nuclear power plants where Compton scattering is the dominant attenuation mechanism. The buildup factor method is reviewed; its use and misuse are discussed. Several useful rules-of-thumb are developed. The paper emphasizes the need for understanding the fundamental physics and draws heavily on the old, classic references

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

    International Nuclear Information System (INIS)

    Wu Hongying; Wang Yueying; Li Deguan; Wang Xiaochun; Zhang Heng; Lu Lu; Chang Jianhui; Du Liqing; Wang Yan; Men Aimin

    2010-01-01

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

  7. Fourth IRMF comparison of calibrations of portable gamma-ray dose- rate monitors 2001-2002 Ionising radiation

    CERN Document Server

    Lewis, V E

    2002-01-01

    The Ionising Radiations Metrology Forum (IRMF) organised a fourth comparison of calibrations of gamma-ray dose-rate monitors in which fifteen establishments in the UK participated. The exercise involved the circulation of three gamma-ray monitors for calibration in the fields produced using sup 1 sup 3 sup 7 Cs, sup 2 sup 4 sup 1 Am and sup 6 sup 0 Co. The instruments used were an Electra with MC 20 probe, a Mini-Instruments Mini-rad 1000 and a Siemens electronic personal dosemeter Mk 2 (EPD). The responses relative to 'true' dose equivalent rate were calculated by the individual participants and submitted to the for analysis along with details of the facilities and fields employed. Details of the estimated uncertainties were also reported. The results are compared and demonstrate generally satisfactory agreement between the participating establishments. However, the participants' treatment of uncertainties needs improvement and demonstrates a need for guidance in this area.

  8. Dose Rate of Environmental Gamma Radiation in Java Island

    International Nuclear Information System (INIS)

    Gatot Suhariyono; Buchori; Dadong Iskandar

    2007-01-01

    The dose rate Monitoring of environmental gamma radiation at some locations in Java Island in the year 2005 / 2006 has been carried out. The dose rate measurement of gamma radiation is carried out by using the peripheral of Portable Gamma of Ray Spectrometer with detector of NaI(Tl), Merck Exploranium, Model GR-130- MINISPEC, while to determine its geographic position is used by the GPS (Global Positioning System), made in German corporation of GPS III Plus type. The division of measurement region was conducted by dividing Java Island become 66 parts with same distance, except in Jepara area that will built PLTN (Nuclear Energy Power), distance between measurement points is more closed. The results of dose rate measurement are in 66 locations in Java Island the range of (19.24 ± 4.05) nSv/hour until (150.78 ± 12.26) nSv/hour with mean (51.93 ± 36.53) nSv/h. The lowest dose rate was in location of Garut, while highest dose rate was in Ujung Lemah Abang, Jepara location. The data can be used for base line data of dose rate of environmental gamma radiation in Indonesia, specially in Java Island. The mean level of gamma radiation in Java monitoring area (0.46 mSv / year) was still lower than worldwide average effective dose rate of terrestrial gamma rays 0.5 mSv / year (report of UNSCEAR, 2000). (author)

  9. Specific activities and the relevant gamma ray dose rates at 1 meter from radioisotopes and isomers following thermal neutron capture reaction

    International Nuclear Information System (INIS)

    Eissa, E.A.; Aly, R.A.; Gomaa, M.A.; Hassan, A.M.

    1995-01-01

    Calculations were performed for the specific activity of 245 gamma-ray emitting radioisotopes and isomers produced in 48, 72 and 96 hour irradiation periods of the natural isotopic mixture of their 77 elements with thermal neutron flux 1.0 E + 13 n/cm 2 .5, at the core of the (ET-R R-1) reactor. The relevant gamma-ray dose rate at a point 1 meter apart from each radioisotope or isomer was evaluated whenever the specific gamma-ray dose rate constant is available. The irradiation time factor (ITF) for the irradiation periods 24, 48, 72 and 96 hours are reported for each of the 248 gamma-ray emitters. The average of (ITF) over these 248 radionuclides for each irradiation period is taken as a measure of the feasibility of the irradiation time. The results favour the increase of the irradiation period from the conventional 48 to 72 hours but not to 96 hours. A programme was established in the VAX computer to carry out the above mentioned calculations. Tables of the present work are very useful for isotope production and reactor safety. 1 fig., 2 tabs

  10. Effectiveness of gamma ray irradiation and ethyl methane ...

    African Journals Online (AJOL)

    Survival rate and plantlet performance of DNKW001 in gamma ray + EMS 7uM treatment declined profoundly with increasing doses and LD50 was lower (104 Gy) than LD50 in gamma ray irradiation (177 Gy) alone. Variants of plantlets were detected in pre (white streaked leaf and bigger petiole with distorted leaf) and post ...

  11. Effect of low gamma ray doses on sugar beet

    International Nuclear Information System (INIS)

    Al-Oudat, M.

    1993-01-01

    We studied the effect of presowing irradiation simulation on sugar beet seeds in two regions (Deir Elzour and Damascus) and for three successive cropping seasons (1986-1989). Those seeds were irradiated with gamma radiation doses varying from 0.005 to 0.050 kGy in the first region, and from 0.005 to 0.025 kGy in the second region. Results showed that doses varying from 0.005 to 0.05 kGy in Deir Elzour gave a mean yield increase varying from 17.4% to 22.6%. However, doses varying from 0.005 to 0.025 in Damascus gave an increase of the same parameter between 19.5% and 23.8%. The best results for pure sugar yield increase obtained for a dose of 0.015 kGy (27.1% in Deir Elzour and 31.9% in Damascus). Yields on the farm level obtained from presowing irradiated seeds showed an increase in sugar beets when using 0.015 kGy gamma radiation dose. (author)

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

    Science.gov (United States)

    Hijaz, Faraj M; Smith, J Scott

    2010-01-01

    Food irradiation improves food safety and maintains food quality by controlling microorganisms and extending shelf life. However, acceptance and commercial adoption of food irradiation is still low. Consumer groups such as Public Citizen and the Food and Water Watch have opposed irradiation because of the formation of 2-alkylcyclobutanones (2-ACBs) in irradiated, lipid-containing foods. The objectives of this study were to measure and to compare the level of 2-dodecylcyclobutanone (2-DCB) in ground beef irradiated by low-energy X-rays and gamma rays. Beef patties were irradiated by low-energy X-rays and gamma rays (Cs-137) at 3 targeted absorbed doses of 1.5, 3.0, and 5.0 kGy. The samples were extracted with n-hexane using a Soxhlet apparatus, and the 2-DCB concentration was determined with gas chromatography-mass spectrometry. The 2-DCB concentration increased linearly (P irradiation dose for gamma-ray and low-energy X-ray irradiated patties. There was no significant difference in 2-DCB concentration between gamma-ray and low-energy X-ray irradiated patties (P > 0.05) at all targeted doses. © 2010 Institute of Food Technologists®

  13. Effects of single and split doses of cobalt-60 gamma rays and 14 MeV neutrons on mouse stem cell spermatogonia.

    Science.gov (United States)

    Hacker-Klom, U B; Köhnlein, W; Göhde, W

    2000-12-01

    The long-term effects of ionizing radiation on male gonads may be the result of damage to spermatogonial stem cells. Doses of 10 cGy to 15 Gy (60)Co gamma rays or 10 cGy to 7 Gy 14 MeV neutrons were given to NMRI mice as single or split doses separated by a 24-h interval. The ratios of haploid spermatids/2c cells and the coefficients of variation of DNA histogram peaks as measures of both the cytocidal and the clastogenic actions of radiation were analyzed by DNA flow cytometry after DAPI staining. The coefficient of variation is not only a statistical examination of the data but is also used here as a measure of residual damage to DNA (i.e. a biological dosimeter). Testicular histology was examined in parallel. At 70 days after irradiation, the relative biological effectiveness for neutrons at 50% survival of spermatogonial stem cells was 3.6 for single doses and 2.8 for split doses. The average coefficient of variation of unirradiated controls of elongated spermatids was doubled when stem cells were irradiated with single doses of approximately 14 Gy (60)Co gamma rays or 3 Gy neutrons and observed 70 days later. Split doses of (60)Co gamma rays were more effective than single doses, doubling DNA dispersion at 7 Gy. No fractionation effect was found with neutrons with coefficients of variation.

  14. Gamma ray generator

    Science.gov (United States)

    Firestone, Richard B; Reijonen, Jani

    2014-05-27

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

  15. Gamma-ray dose analysis for ITER JA WCCB-TBM

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Satoshi, E-mail: sato.satoshi92@jaea.go.jp [Japan Atomic Energy Agency, Tokai-mura, Ibaraki (Japan); Tanigawa, Hisashi; Hirose, Takanori; Enoeda, Mikio [Japan Atomic Energy Agency, Naka-shi, Ibaraki (Japan); Ochiai, Kentaro; Konno, Chikara [Japan Atomic Energy Agency, Tokai-mura, Ibaraki (Japan)

    2014-10-15

    To evaluate the nuclear properties of the International Thermonuclear Experimental Reactor (ITER) JA Water-Cooled Ceramic Breeder Test Blanket Module (WCCB-TBM) and to ensure its design conforms to nuclear licensing regulations, nuclear analyses have been performed for the WCCB-TBM's components, including its frame, shield, flange, port extension, pipe forest, bio-shield and Ancillary Equipment Unit (AEU). Utilising Monte Carlo code MCNP5.14, activation code ACT-4 and the Fusion Evaluated Nuclear Data Library FENDL-2.1, this paper focusses on the shutdown dose rate calculation for the WCCB-TBM. Monte Carlo N-Particle Transport Code (MCNP) geometry input data for the TBM are created from computer-aided design (CAD) data using the CAD/MCNP automatic conversion code GEOMIT, and other geometry input data are created manually. The ‘Direct 1-Step Monte Carlo’ method is adopted for the decay gamma-ray dose rate calculation. Behind the bio-shield, the effective dose rates 1 day after shutdown are about 0.2 μSv h{sup −1}, which are much lower than 10 μSv h{sup −1}, the upper limit for human access. Behind the flange, the effective dose rates 10{sup 6} s after shutdown are 50–80 μSv h{sup −1}, which are lower than 100 μSv h{sup −1}, the upper limit for human hands-on access for workers performing maintenance.

  16. Determination of stimulation effective dose of gamma ray on guinea pig to be used for antibody production

    International Nuclear Information System (INIS)

    Arifin, Muchson; Soewarsono, M.

    1983-01-01

    The experiment has been performed on guinea pigs which were irradiated by gamma rays with doses of 0, 150, 300 and 600 rad. Observations were carried out on peripheral blood in regard to red blood cell, white blood cell and haemoglobine, every week after irradiation. +he result obtained showed that 150 rad was the optimal stimulation effective dose for antibody production in guinea pigs. (author)

  17. Determination of stimulation effective dose of gamma ray on guinea pig to be used for antibody production

    Energy Technology Data Exchange (ETDEWEB)

    Arifin, M; Soewarsono, M [National Atomic Energy Agency, Jakarta (Indonesia). Pasar Djumat Research Centre

    1983-04-01

    The experiment has been performed on guinea pigs which were irradiated by gamma rays with doses of 0, 150, 300 and 600 rad. Observations were carried out on peripheral blood in regard to red blood cell, white blood cell and haemoglobine, every week after irradiation. The result obtained showed that 150 rad was the optimal stimulation effective dose for antibody production in guinea pigs. 10 refs.

  18. A MATHEMATICAL APPROACH TO ECONOMY OF EXPERIMENT IN DETERMINATIONS OF THE DIFFERENTIAL DOSE ALBEDO OF GAMMA RAYS

    Energy Technology Data Exchange (ETDEWEB)

    Shoemaker, N. F.; Huddleston, C. M.

    1962-12-10

    Treatments of the differential dose albedo of gamma rays on concrete have supposed that the albedo value is a function of: the energy of the incident gamma radiation, the polar angle of incidence, the polar angle of reflection (or scatter), and the azimuthal angle of reflection. It is demonstrated that, if certain reasonable assumptions are made regarding the mechanism of reflection, it is not necessary to investigate variations in albedo with azimuthal angle of refiection. Once differential dose albedo has been determined for a complete set of incident and reflected polar angles with zero azimuth, albedo at any azimuth can be derived by a suitable transformation. (auth)

  19. Effect of anti-sprouting gamma-ray doses on enzymatic fromation of flavour odor compounds in onion (Allium Cipa L)

    International Nuclear Information System (INIS)

    El-Sayed, S.A.; El-Waziri, S.M.

    1977-01-01

    Cysteine sulfoxide lyase activity, the development of lacrimatory factor and intensity of pungent flavour had been decreased, statistically, with increasing anti-sprouting gamma-ray dose and storage period after irradiation. Inactivation of lyase caused by 5 and 10 krad was perfectly recovered by the storage. The lyase activity was reactivated to unirradiated level at 4-5 months storage, respectively, under room temperature (20-25 C and 85-75%R.H.). 15kr inhibited the enzyme activity and could not be completely recovered and the characteristic flavour as well as the lacrimatory factor were drastically decreased by increasing storage time. Therefore, 10krad seems to be the maximum gamma ray dose proper for sprout-inhibition of Egyptian onions, Giza 6 variety, from technological point of view

  20. Electrical characteristics of {sup 60}Co {gamma}-ray irradiated MIS Schottky diodes

    Energy Technology Data Exchange (ETDEWEB)

    Tataroglu, A. [Department of Physics, Faculty of Arts and Sciences, Gazi University, 06500 Ankara (Turkey)]. E-mail: ademt@gazi.edu.tr; Altindal, S. [Department of Physics, Faculty of Arts and Sciences, Gazi University, 06500 Ankara (Turkey)

    2006-11-15

    In order to interpret the effect of {sup 60}Co {gamma}-ray irradiation dose on the electrical characteristics of MIS Schottky diodes, they were stressed with a zero bias at 1 MHz in dark and room temperature during {gamma}-ray irradiation and the total dose range was 0-450 kGy. The effect of {gamma}-ray exposure on the electrical characteristics of MIS Schottky diodes has been investigated using C-V and G/{omega}-V measurements at room temperature. Experimental results show that {gamma}-ray irradiation induces a decrease in the barrier height {phi} {sub B} and series resistance R {sub s}, decreasing with increasing dose rate. Also, the acceptor concentration N {sub A} increases with increasing radiation dose. The C-V characteristics prove that there is a reaction for extra recombination centers in case of MIS Schottky diodes exposed to {gamma}-ray radiation. Furthermore, the density of interface states N {sub ss} by Hill-Coleman method increases with increasing radiation dose. Experimental results indicate that the interface-trap formation at high irradiation dose is reduced due to positive charge build-up in the Si/SiO{sub 2} interface (due to the trapping of holes) that reduces the flow rate of subsequent holes and protons from the bulk of the insulator to the Si/SiO{sub 2} interface.

  1. Radium equivalent activity of building materials and gamma ray dose rates in ordinary houses of Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Campos, M.P.; Pecequilo, B.R.S.

    1994-01-01

    The external radiation exposure from natural radioactivity represents, approximately, 50% of the average annual dose caused to the human body by all natural and artificial radiation sources. Natural radioactivity in building materials is the most important source of external radiation exposure in dwellings because of the gamma rays emitted from potassium 40 and member of the uranium 238 and thorium 232 decay chains. Concrete is one of the most potential sources of elevated radiation exposure, however, little is known about the natural radioactivity of Brazilian construction materials. A study to predict the exposure rates of several ordinary houses built almost of concrete, consisting of 38 samples of 6 different materials was conducted by using high resolution gamma-ray spectrometry. The radium equivalent activity was calculated for all 38 samples in order to compare the specific activities of the construction materials containing different amounts of radium, thorium, and potassium. The effective dose rate due to the indoor gamma radiation from the building materials was performed following the 1988 UNSCEAR procedures

  2. Relationship between terrestrial gamma ray dose rates and geology of Awaji Island in Hyogo Prefecture

    International Nuclear Information System (INIS)

    Shibayama, Motohiko; Hiraoka, Yoshitsugu; Ikeda, Tadashi; Terado, Shin

    2004-01-01

    In order to clarify the relationship between terrestrial gamma ray dose rates and surface geology, measurements were carried out for the entire part f Awaji Island in Hyogo Prefecture. The results of analysis were summarized as follows. (1) The mean value for each geology was nearly the same as that in the whole of Japan. (2) The granitic rocks can be divided into three groups, based on their stages of intrusion (Tainsyo, 1985). the dose rate levels for granitic rocks increased from fast stage over third stage. (author)

  3. Calculational methods for estimating skin dose from electrons in Co-60 gamma-ray beams

    International Nuclear Information System (INIS)

    Higgins, P.D.; Sibata, C.H.; Attix, F.H.; Paliwal, B.R.

    1983-01-01

    Several methods have been employed to calculate the relative contribution to skin dose due to scattered electrons in Co-60 gamma-ray beams. Either the Klein-Nishina differential scattering probability is employed to determine the number and initial energy of electrons scattered into the direction of a detector, or a Gaussian approximation is used to specify the surface distribution of initial pencil electron beams created by parallel or diverging photon fields. Results of these calculations are compared with experimental data. In addition, that fraction of relative surface dose resulting from photon interactions in air alone is estimated and compared with data extrapolated from measurements at large source-surface distance (SSD). The contribution to surface dose from electrons generated in air is 50% or more of the total skin dose for SSDs greater than 80 cm

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

    CERN Document Server

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

    2002-01-01

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

  5. The calculation of external gamma-ray doses from airborne and deposited radionuclides in the environmental code NECTAR

    International Nuclear Information System (INIS)

    Corbett, J.O.

    1982-02-01

    A computer program has been developed for the rapid evaluation of external gamma-ray doses from airborne and deposited radionuclide mixtures. Based on a gaussian dispersion model, the program calculates the dose at any position, including points high above ground level or upwind of the source. Meteorological frequency data for wind speed, direction, atmospheric stability and rainfall are fully taken into account. The calculational model assumes that the ground surface is perfectly flat and that gamma-ray paths are entirely in air; the possible errors caused by these and other assumptions are discussed, with suggested correction factors. The program applies various criteria to determine the best approximation or numerical integration method for each target point; execution times (on an IBM 370 machine) thus vary from less than 0.01s to about 0.3s per target point for a single weather category. The program has been incorporated in the environmental release program NECTAR. (author)

  6. Dose-response of photographic emulsions under gamma irradiation

    International Nuclear Information System (INIS)

    Tran Dai Nghiep; Do Thi Nguyet Minh; Le Van Vinh

    2003-01-01

    Photographic emulsion is irradiated under gamma rays irradiation of 137 Cs in the IAEA/WHO secondary standard dosimetry laboratory. Dose-response of the film is established. The sensitivity of the film is determined. The dose-rate effect is studied. (author)

  7. Assessment of background gamma radiation levels using airborne gamma ray spectrometer data over uranium deposits, Cuddapah Basin, India - A comparative study of dose rates estimated by AGRS and PGRS.

    Science.gov (United States)

    Srinivas, D; Ramesh Babu, V; Patra, I; Tripathi, Shailesh; Ramayya, M S; Chaturvedi, A K

    2017-02-01

    The Atomic Minerals Directorate for Exploration and Research (AMD) has conducted high-resolution airborne gamma ray spectrometer (AGRS), magnetometer and time domain electromagnetic (TDEM) surveys for uranium exploration, along the northern margins of Cuddapah Basin. The survey area includes well known uranium deposits such as Lambapur-Peddagattu, Chitrial and Koppunuru. The AGRS data collected for uranium exploration is utilised for estimating the average absorbed rates in air due to radio-elemental (potassium in %, uranium and thorium in ppm) distribution over these known deposit areas. Further, portable gamma ray spectrometer (PGRS) was used to acquire data over two nearby locations one from Lambapur deposit, and the other from known anomalous zone and subsequently average gamma dose rates were estimated. Representative in-situ rock samples were also collected from these two areas and subjected to radio-elemental concentration analysis by gamma ray spectrometer (GRS) in the laboratory and then dose rates were estimated. Analyses of these three sets of results complement one another, thereby providing a comprehensive picture of the radiation environment over these deposits. The average absorbed area wise dose rate level is estimated to be 130 ± 47 nGy h -1 in Lambapur-Peddagattu, 186 ± 77 nGy h -1 in Chitrial and 63 ± 22 nGy h -1 in Koppunuru. The obtained average dose levels are found to be higher than the world average value of 54 nGy h -1 . The gamma absorbed dose rates in nGy h -1 were converted to annual effective dose rates in mSv y -1 as proposed by the United Nations Scientific Committee on the Effect of Atomic Radiation (UNSCEAR). The annual average effective dose rates for the entire surveyed area is 0.12 mSv y -1 , which is much lower than the recommended limit of 1 mSv y -1 by International Commission on Radiation protection (ICRP). It may be ascertained here that the present study establishes a reference data set (baseline) in these areas

  8. Observations of the highest energy gamma-rays from gamma-ray bursts

    International Nuclear Information System (INIS)

    Dingus, Brenda L.

    2001-01-01

    EGRET has extended the highest energy observations of gamma-ray bursts to GeV gamma rays. Such high energies imply the fireball that is radiating the gamma-rays has a bulk Lorentz factor of several hundred. However, EGRET only detected a few gamma-ray bursts. GLAST will likely detect several hundred bursts and may extend the maximum energy to a few 100 GeV. Meanwhile new ground based detectors with sensitivity to gamma-ray bursts are beginning operation, and one recently reported evidence for TeV emission from a burst

  9. Micronuclei induced by fast neutrons versus 60Co gamma-rays in human peripheral blood lymphocytes.

    Science.gov (United States)

    Vral, A; Verhaegen, F; Thierens, H; De Ridder, L

    1994-03-01

    Here we compared the effectiveness of neutrons ( = 5.5 MeV) versus 60Co gamma-rays in producing micronuclei (MN) in human lymphocytes. To obtain dose-response data, blood samples of six donors were irradiated with doses ranging from 0.1 to 5 Gy for gamma-rays and 0.1-3 Gy for neutrons. A linear dependence of MN yield with dose was found for fast neutrons while for gamma-rays a nonlinear dependence existed. For both radiation qualities no significant interindividual differences were found. Derived relative biological effectiveness values decreased with increasing dose. The MN frequency distributions were overdispersed with respect to the Poisson distribution, with neutrons showing higher dispersion values than with gamma-rays. To compare the repair kinetics of both radiation qualities split-dose experiments were performed. A dose of 4 Gy gamma-rays (3 Gy neutrons) was delivered either as a single exposure or in two equal fractions separated by time intervals ranging from 30 min to 10 h (30 min to 7 h for neutrons). The data showed for gamma-rays a significant decline (30% +/- 10%) in MN yield with interfraction time due to repair of DNA damage. This repair is a continuous process starting almost immediately after the first of the two doses and lasting 3-5 h. For fast neutrons no decline was observed indicating irreparable damage.

  10. The effect of gamma dose on the PADC detectors

    International Nuclear Information System (INIS)

    Zaky, M.F.; Youssef, A.A.

    2002-01-01

    The effect of irradiation by 6 0C O gamma rays in the range 0-60 K gray has been examined on CR-39 SSNTDs. The fission fragment tracks diameter were measured using an optical microscope, the bulk etching rate was calculated using the equation V B = D/2 t. The results indicate that, the track diameter is seen increase slowly in the range 0-60 K gray. The bulk etching rate increases almost linearly as the given gamma dose increases up to (22.5 K Gray), at higher doses the bulk etching rate increases exponentially. The exposure of the CR-39 to gamma rays could sensitize the CR-39 plastic and thus improve the Z/P threshold for track registration

  11. Low Doses of Gamma Rays Reduce the Sensitivity of Cervical Carcinoma Cells to Subsequent Treatment with Cisplatin

    International Nuclear Information System (INIS)

    Osmak, M.; Brozovic, A.

    2003-01-01

    One of the major challenges of modern genetics is to apply recent advances in mutation research to improve the accuracy of the estimates of the genetic risk for humans. Because of the important implications for radiation protection, biological effects of low-dose radiation have been a focus of research in recent years. Previously we have found that human cervical carcinoma HeLa cells irradiated repeatedly with low doses of gamma rays (HeLa1500 cells) became resistant to cisplatin. In this study we examine whether this effect was caused by inhibition of apoptosis. In HeLa and HeLa1500 cells we determined the induction of apoptosis following the treatment with cisplatin (i) by counting apoptotic cells with characteristic morphological changes, (ii) by analysing the expression of apoptotic genes involved in cytochrome c/Apaf-1/caspase-9 and in Fas/FasL pathways by Western blot method, and (iii) by estimating the activities of caspases by commercial caspase detection kits. Our results show that low doses of gamma rays induced alterations in human cervical carcinoma cells that were reflected in inhibition of p53-independent cisplatin-induced apoptosis due to reduced activity of caspase 3. (author)

  12. Development of criticality accident detector measuring neutrons and gamma-rays

    International Nuclear Information System (INIS)

    Tsujimura, Norio; Yoshida, Tadayoshi; Ishii, Masato

    2005-01-01

    The authors developed a new criticality accident detector measuring neutrons and gamma-rays. The detector is a cylindrical plastic scintillator coupled to a current-mode operated photomultiplier, and is covered by an inner cadmium shell, acting as a neutron to gamma-ray converter, and a 5cm thick outer polyethylene moderator in order to respond to the same threshold triggering dose regardless of whether it was exposed to neutrons, gamma-rays or a mixture of the two radiations. (author)

  13. Activation of immune functions via induction of glutathione of lymphocytes by low-dose, whole-body irradiation with gamma-rays

    International Nuclear Information System (INIS)

    Shuji Kojima; Hisatake Hayase; Mareyuki Takahashi

    2007-01-01

    Complete text of publication follows. We have recently found that low doses of radiation, unlike higher doses, do not always cause a decrease of cellular glutathione, but they can increase it, leading to an elevation of Con A-induced proliferation of splenocytes. In this study, we first examined whether the increase of glutathione level induced by low-dose gamma-ray irradiation is involved in the appearance of enhanced natural killer (NK) activity and antibody-dependent cellular cytotoxicity (ADCC), leading to delayed tumor growth in Ehrlich solid tumor (EST)-bearing mice. NK activity in ICR mouse splenocytes was significantly increased from 4 h to 6 h after a single whole-body gamma-ray irradiation at 0.5 Gy, and thereafter decreased almost to the zero-time level by 24 h post-irradiation. ADCC was also increased significantly in a similar way. Reduced glutathione exogenously added to splenocytes obtained from normal mice enhanced both NK activity and ADCC in a dose-dependent manner. The inhibitory effect of the radiation on tumor growth was then examined in EST-bearing mice. Repeated low-dose irradiation (0.5 Gy, four times, before and within an early time after the inoculation) significantly delayed the tumor growth. Finally, the effect of single low-dose (0.5 Gy), whole-body gamma-ray irradiation on immune balance (Th1/Th2) was examined in order to elucidate the mechanism underlying the anti-tumor immunity. Recent studies indicate that Th1/Th2 balance plays an important role in the immune responses involved in anti-tumor immunity. The activity of NK is hallmarks of cell-mediated immunity, and play key roles in anti-tumor immunity. The percentage of B cells in blood lymphocytes was selectively decreased after the radiation, concomitantly with an increase in that of helper T cell population, favoring Th1 polarization. The IFN-gamma level in splenocyte culture prepared from EST-bearing mice was significantly increased 48 h after the radiation, though the level of

  14. Mutagenic effects of gamma rays on soybean (Glycine max L.) germination and seedlings

    Science.gov (United States)

    Kusmiyati, F.; Sutarno; Sas, M. G. A.; Herwibawa, B.

    2018-01-01

    Narrow genetic diversity is a main problem restricting the progress of soybean breeding. One way to improve genetic diversity of plant is through mutation. The purpose of this study was to investigate effect of different dose of gamma rays as induced mutagen on physiological, morphological, and anatomical markers during seed germination and seedling growth of soybean. Seeds of soybean cultivars Dering-1 were irradiated with 11 doses of gamma rays (0, 5, 10, 20, 40, 80, 160, 320, 640, 1280, and 2560 Gy [Gray]. The research design was arranged in a completely randomized block design in three replicates. Results showed that soybean seed exposed at high doses (640, 1280, and 2560 Gy) did not survive more than 20 days, the doses were then removed from anatomical evaluation. Higher doses of gamma rays siginificantly reduced germination percentage at the first count and final count, coefficient of germination velocity, germination rate index, germination index, seedling height and seedling root length, and significantly increased mean germination time, first day of germination, last day of germination, and time spread of germination. However, the effects of gamma rays were varies for density, width, and length of stomata. The LD50 obtained based on survival percentage was 314.78 Gy. It can be concluded that very low and low doses of gamma rays (5-320 Gy) might be used to study the improvement of soybean diversity.

  15. Using gamma irradiation for the improvement of MM106 and omara apple Malus domestica Borkh rootstocks to sodium chloride tolerance in Vitro

    International Nuclear Information System (INIS)

    Aljibouri, A.A.M.; Abdel-Hussen, M.A.; Salman, M.A.

    2010-01-01

    In vitro plant lets of MM106 and Omara apple rootstocks were irradiated with gamma ray doses (0, 5, 10, 15, 20, 25, 30, and 35 Gray). Shoot tips of irradiated plant lets with incremental doses were in vitro cultured on MS medium supplemented with different NaCl concentrations to study the effect of gamma rays and NaCl salt on shoot number, shoot length and rooting percentage. Results revealed that gamma rays treatment improved significantly the parameters investigated for both types of rootstocks, especially the doses of 15 and 20 Gy for MM106 and 25 Gy for Omara. On the other hand, salinity caused a significant reduction in all parameters measured with different trend between both types of rootstocks. The results also showed significant interaction between gamma rays doses and NaCl concentrations.

  16. Geochemistry, Radioactivity and Gamma-Ray Dose Assesment of Igneous Rocks, of Abu El Hassan El Aswad Area, North Egypt Eastern Desert

    International Nuclear Information System (INIS)

    Abdel-Monem, A.A.; Moussa, E.M.; Abd El Fattah, M.M.G.; Wetait, M.A.

    2011-01-01

    Abu El Hassan Al Aswad area, Northern Eastern Desert, Egypt, is located between lat. 26 degree 45/ and 26 degree 58 / N and long. 33 degree 0/ and 33 degree 11 /50// E, covering approximately 270 km 2 . It is covered by a suite of igneous rocks, which are classified according to their silica and potash contents into ultra basic rock class with the least silica and potash contents, basic rock class, intermediated rock class and acidic rock class with the highest silica and potash contents. The ultra basic rocks with SiO 2 2 (42-57%), K (0.15-0.5), U (0.8-3 ppm) and Th (1-7 ppm), produce the gamma ray doses (AEDE, 0.266 mSv/y; AGDE, 0.1475 mSv/y). The intermediate rocks with SiO 2 (57-65%), K (0-8-2.5%), U (2-8 ppm) and Th (3.5-14.5 ppm) produce the gamma ray doses (AEDE, 0.083 mSv/y; AGDE, 0.4784 mSv/y). The acidic rocks with SiO 2 (65-75%), K (2.6-4.3%), U (4.5-10 ppm) and Th (13-26 ppm) produce the gamma ray doses (AEDE, 0.1692 mSv/y; AGDE, 0.9571 mSv/y).It is suggested that the ultra basic, basic and the intermediated rock classes can be used safely as building materials as well as for indoor and outdoor decorations. The acidic rock class may be used for outdoor decorations but not as building materials or indoor decoration due to its high AGDE values, which when added to the other gamma ray exposure source may exceed the International Accepted Radiation Dose Limit to member of the public which is (1-3 mSv/y)

  17. Effect of Gamma Rays on Some Biological performance of Chrysomya bezziana(VILL.)

    International Nuclear Information System (INIS)

    Al Seria, M. H.; Al Taweel, A.A.; Ahmed, A.M.; Al Izzi, M.A.J.

    2006-01-01

    The effect of different does of gamma rays on some biological performance of Old World Screwworm fly (OWSWF), Chrysomya bezziana exposed as pupae at different ages were investigated. Results reveealed that the ages of produced adults were effected significantly as the dose of gamma rays increased and the ages of irradiated pupae decreased While no effect was observed in sex ratio of emerged adults at any ages of irradiated pupae. The results have also showed that the female fecundity and percent of egg hatch were significantly effected as the dose of gamma ray increased for both type of mating investigated.

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

    International Nuclear Information System (INIS)

    Scaff, Luiz Alberto Malaguti

    2001-01-01

    Physical factors associated to total body irradiation using 60 Co gamma rays beams, were studied in order to develop a calculation method of the dose distribution that could be reproduced in any radiotherapy center with good precision. The method is based on considering total body irradiation as a large and irregular field with heterogeneities. To calculate doses, or doses rates, of each area of interest (head, thorax, thigh, etc.), scattered radiation is determined. It was observed that if dismagnified fields were considered to calculate the scattered radiation, the resulting values could be applied on a projection to the real size to obtain the values for dose rate calculations. In a parallel work it was determined the variation of the dose rate in the air, for the distance of treatment, and for points out of the central axis. This confirm that the use of the inverse square law is not valid. An attenuation curve for a broad beam was also determined in order to allow the use of absorbers. In this work all the adapted formulas for dose rate calculations in several areas of the body are described, as well time/dose templates sheets for total body irradiation. The in vivo dosimetry, proved that either experimental or calculated dose rate values (achieved by the proposed method), did not have significant discrepancies. (author)

  19. Effects of dose fractionation on the response of alanine dosimetry

    International Nuclear Information System (INIS)

    Lundahl, Brad; Logar, John; Desrosiers, Marc; Puhl, James

    2014-01-01

    Alanine dosimetry is well established as a transfer standard and is becoming more prevalently used in routine dosimetry systems for radiation processing. Many routine measurement applications in radiation processing involve absorbed dose measurements resulting from fractioned exposures to ionizing radiation. Fractioning of absorbed dose is identified as an influence quantity (ISO/ASTM, 2013). This paper reports on study results of absorbed dose fractioning characteristics of alanine for gamma and high energy electron beam radiation sources. The results of this study indicate a radiation response difference due to absorbed dose fractioning in response can be observed after four fractionations for high-energy electron beams and no difference up to seven fractions for gamma rays using an ANOVA evaluation method. - Highlights: • Fractioning effects signaled in electron beam using an ANOVA at 6 equal increments. • Fractioning effects not signaled in gamma using an ANOVA up to 7 equal increments. • Insensitivity of alanine to dose fractioning indicates nominal impact on calibration

  20. Gamma ray benchmark on the spent fuel shipping cask TN 12

    International Nuclear Information System (INIS)

    Blum, P.; Cagnon, R.; Cladel, C.; Ermont, G.; Nimal, J.C.

    1983-05-01

    The purpose of this benchmark is to compare measurements and calculation of gamma-ray dose rates around a shipping cask loaded with 12 spent fuel elements of FESSENHEIM PWR type. The benchmark provides a means to verify gamma-ray sources and gamma-ray transport calculation methods in shipping cask configurations. The comparison between measurements and calculations shows a good agreement except near the fuel element top where the discrepancy reaches a factor 2

  1. Inactivation of HTB63 human melanoma cells by irradiation with protons and gamma rays.

    Science.gov (United States)

    Ristic-Fira, Aleksandra; Petrovic, Ivan; Todorovic, Danijela; Koricanac, Lela; Vujèic, Miroslava; Demajo, Miroslav; Sabini, Gabriella; Cirrone, Pablo; Cuttone, Giacomo

    2004-12-01

    The effects of single irradiation with gamma rays and protons on HTB63 human melanoma cell growth were compared. The exponentially growing cells were irradiated with gamma rays or protons using doses ranging from 2-20 Gy. At 48 h of post-irradiation incubation under standard conditions, cell survival and induction of apoptotic cell death were examined. The best effect of the single irradiation with gamma rays was the reduction of cell growth by up to 26% (p=0.048, irradiation vs. control), obtained using the dose of 16 Gy. The same doses of proton irradiation, having energy at the target of 22.6 MeV, significantly inhibited melanoma cell growth. Doses of 12 and 16 Gy of protons provoked growth inhibition of 48.9% (p=0.003, irradiation vs. control) and 51.2% (p=0.012, irradiation vs. control) respectively. Irradiation with 12 and 16 Gy protons, compared to the effects of the same doses of gamma rays, significantly reduced melanoma cell growth (p=0.015 and p=0.028, protons vs. gamma rays, respectively). Estimated RBEs for growth inhibition of HTB63 cells ranged from 1.02 to 1.45. The electrophoretical analyses of DNA samples and flow cytometric evaluation have shown a low percentage of apoptotic cells after both types of irradiation. The better inhibitory effect achieved by protons in contrast to gamma rays, can be explained considering specific physical properties of protons, especially taking into account the highly localized energy deposition (high LET).

  2. Gamma-ray spectra and doses from the Little Boy replica

    International Nuclear Information System (INIS)

    Moss, C.E.; Lucas, M.C.; Tisinger, E.W.; Hamm, M.E.

    1984-01-01

    Most radiation safety guidelines in the nuclear industry are based on the data concerning the survivors of the nuclear explosions at Hiroshima and Nagasaki. Crucial to determining these guidelines is the radiation from the explosions. We have measured gamma-ray pulse-height distributions from an accurate replica of the Little Boy device used at Hiroshima, operated at low power levels near critical. The device was placed outdoors on a stand 4 m from the ground to minimize environmental effects. The power levels were based on a monitor detector calibrated very carefully in independent experiments. High-resolution pulse-height distributions were acquired with a germanium detector to identify the lines and to obtain line intensities. The 7631 to 7645 keV doublet from neutron capture in the heavy steel case was dominant. Low-resolution pulse-height distributions were acquired with bismuth-germanate detectors. We calculated flux spectra from these distributions using accurately measured detector response functions and efficiency curves. We then calculated dose-rate spectra from the flux spectra using a flux-to-dose-rate conversion procedure. The integral of each dose-rate spectrum gave an integral dose rate. The integral doses at 2 m ranged from 0.46 to 1.03 mrem per 10 13 fissions. The output of the Little Boy replica can be calculated with Monte Carlo codes. Comparison of our experimental spectra, line intensities, and integral doses can be used to verify these calculations at low power levels and give increased confidence to the calculated values from the explosion at Hiroshima. These calculations then can be used to establish better radiation safety guidelines. 7 references, 7 figures, 2 tables

  3. The effect of low dose gamma irradiation on maize production (1985-1988)

    International Nuclear Information System (INIS)

    Al-Oudat, M.; Khalifa, K.

    1990-06-01

    Presowing seed irradiation has been reported as a useful application of radiation in agriculture to stimulate growth and increase the yield of certain field crops. To the best of our knowledge the feasibility of this treatment has not yet been tested on maize in Syria. Our experiments were carried out in controlled, in field conditions, and in a large scale application. Samples of air dried seeds of maize (Var. Gota-82 and LG-11) of previous season were irradiated by gamma-rays from a 137 Cs sourse using doses of 5, 7.5, 10, 15, 20, 30, 40 and 50 Gy. at dose rate of 9.8 - 9.2 Gy/min. Then were planted after 2 days from irradiation with unirradiated control, in complete randomized block design and replicated 4 times for four seasons (1985-1988). The date revealed that gamma irradiation, at interval doses of 5 - 10 Gy led to, first: Acceleration of seed germination, faster development, intensive development of root system, increase plant hieght (12 - 19%) and significant increase in ear size and number, and second: Increase both green mass (15 - 35%) and seed yield (10 - 31%), and percentage of seed protein (2 - 17%). Large scale applications were performed in 1987 and 1988 using a transportable irradiation unit POC-1 137 Cs and dose of 7.5 Gy. A significant yield increase was obtained from all fields. The average percentage increment varied from 13 - 30% which is approximately 382-765 Kg/h. Therefore, presowing seed irradiation with low doses gamma irradiation ranging from 5 to 10 Gy, was found to be feasible for application in qualitative and quantitative improvement of maize yield. (author). 38 refs., 12 figs., 44 tabs

  4. Gamma ray induced fruit quality variations in banana variety Nendran (Musa Paradasiaca L.)

    International Nuclear Information System (INIS)

    Radha Devi, D.S.; Nayer, N.K.

    1992-01-01

    Gamma ray induced fruit quality variation was envisaged to analyse the direct effect of Co 60 gamma rays in banana variety Nendran. Fruit quality analysis showed that the total soluble solids and acidity decreased and total sugar and sugar acid ratio increased with increase in dose of gamma ray exposures. (author). 5 refs., 1 tab

  5. Dosimetry for terrestrial gamma-ray sources

    International Nuclear Information System (INIS)

    Abdullah, S.A.; Dickson, H.W.; Kerr, G.D.; Miah, M.F.K.; Perdue, P.T.

    1975-01-01

    Dose rates from natural radionuclides and 137 Cs in soils of the Oak Ridge area have been determined from in situ and core sample measurements. Information on soil composition, density, and moisture content and on the distribution of cesium in the soil was obtained from the core samples. Measurements of radionuclide concentrations in the samples were made with a 4 x 4 in. NaI detector. Gamma-ray spectroscopy using a lithium-drifted germanium (GeLi) detector has been applied to the determination of radionuclide concentrations in soil and the associated gamma dose rates above the earth plane. An unshielded GeLi detector placed about 1 m above the earth detects gamma radiation from an area of about 100 m 2 . The equipment and data processing procedure are briefly described

  6. Conversion of Airborne Gamma ray Spectra to Ground Level Air Kerma Rates

    DEFF Research Database (Denmark)

    Bargholz, Kim; Korsbech, Uffe C C

    1997-01-01

    A new method for relating airborne gamma-ray spectra to dose rates and kerma rates at ground level is presented. Dependent on flying altitude 50 m to 125 m the method gives correct results for gamma energies above 250 keV respective 350 keV. At lower energies the method underestimate the dose...... or kerma rates; by having a large fraction of the ground level gamma-rays at energies below 350 keV special care should be taken at an interpretation of the results....

  7. Practice for dosimetry for a self-contained dry-storage gamma-ray irradiator

    International Nuclear Information System (INIS)

    2002-01-01

    This practice outlines dosimetric procedures to be followed with self-contained dry-storage gamma-ray irradiators. If followed, these procedures will help to ensure that calibration and testing will be carried out with acceptable precision and accuracy and that the samples processed with ionizing radiation from gamma rays in a self-contained dry-storage irradiator receive absorbed doses within a predetermined range. This practice covers dosimetry in the use of dry-storage gamma-ray irradiators, namely self-contained dry storage 137 Cs or 60 Co irradiators (shielded free-standing irradiators). It does not cover underwater pool sources, panoramic gamma-ray sources such as those raised mechanically or pneumatically to irradiate isotropically into a room or through a collimator, nor does it cover self-contained bremsstrahlung x-ray units. The absorbed dose range for the use of the dry-storage self-contained gamma-ray irradiators covered by this practice is typically 1 to 10 5 Gy, depending on the application. The absorbed-dose rate range typically is from 10 -2 to 10 3 Gy/min. This practice describes general procedures applicable to all self-contained dry-storage gamma-ray irradiators. For procedures specific to dosimetry in blood irradiation, see ISO/ ASTM Practice 51939. For procedures specific to dosimetry in radiation research on food and agricultural products, see ISO/ASTM Practice 51900. For procedures specific to radiation hardness testing, see ASTM Practice E 1249. For procedures specific to the dosimetry in the irradiation of insects for sterile release programs, see ISO/ASTM Guide 51940. In those cases covered by ISO/ASTM Practices 51939, 51900, 51940, or ASTM E 1249, those standards take precedence. In addition, this practice does not cover absorbed-dose rate calibrations of radiation protection instrumentation

  8. Gamma-ray streaming in bent ducts and voids

    International Nuclear Information System (INIS)

    Bourdet, L.; Nimal, J.C.; Vergnaud, T.

    1983-05-01

    We have developed an analytical method to calculate gamma-ray streaming through straight ducts and a numerical method to study the gamma propagation in bends or in annular clearances. The whole set allows a rigorous treatment of gamma streaming through bent ducts. In the same time a Monte Carlo method allows to study any form of geometry, by using sophisticated biasing techniques. All these developments are made with a simplified albedo. An easy to use code is also proposed to calculate very general albedos and a code to calculate the dose rate due to reflection in a room. Gamma dose rate albedos are determined for all elements and the energy range which concerns fission reactors

  9. Dose profile monitoring with carbon ions by means of prompt-gamma measurements

    Energy Technology Data Exchange (ETDEWEB)

    Testa, E. [Institut de Physique Nucleaire de Lyon, Universite de Lyon, F-69003 Lyon, Universite Lyon 1 and IN2P3/CNRS, UMR 5822, F-69622 Villeurbanne (France)], E-mail: e.testa@ipnl.in2p3.fr; Bajard, M.; Chevallier, M.; Dauvergne, D.; Le Foulher, F. [Institut de Physique Nucleaire de Lyon, Universite de Lyon, F-69003 Lyon, Universite Lyon 1 and IN2P3/CNRS, UMR 5822, F-69622 Villeurbanne (France); Freud, N.; Letang, J.M. [Institut National des Sciences Appliquees de Lyon, Laboratoire de Controle Non-Destructif par Rayonnements Ionisants (France); Poizat, J.C.; Ray, C.; Testa, M. [Institut de Physique Nucleaire de Lyon, Universite de Lyon, F-69003 Lyon, Universite Lyon 1 and IN2P3/CNRS, UMR 5822, F-69622 Villeurbanne (France)

    2009-03-15

    A key point in the quality control of ion therapy is real-time monitoring and imaging of the dose delivered to the patient. Among the possible signals that can be used to make such a monitoring, prompt gamma-rays issued from nuclear fragmentation are possible candidates, provided the correlation between the emission profile and the primary beam range can be established. By means of simultaneous energy and time-of-flight discrimination, we could measure the longitudinal profile of the prompt gamma-rays emitted by 73 MeV/u carbon ions stopping inside a PMMA target. This technique allowed us to minimize the shielding against neutrons and scattered gamma rays, and to find a good correlation between the prompt-gamma profile and the ion range. This profile was studied as a function of the observation angle. By extrapolating our results to higher energies and realistic detection efficiencies, we showed that prompt gamma-ray measurements make it feasible to control in real time the longitudinal dose during ion therapy treatments.

  10. Effects of gamma-ray radiation on activity and apoptosis of rat cardiomyocytes in vitro

    International Nuclear Information System (INIS)

    Hu Shunying; Jiang Changsheng; Chen Guowei; Duan Haifeng; Wang Rongliang; Wu Bin; Guo Zikuan; Wang Lisheng

    2007-01-01

    Objective: It is reported that radiation-induced myocardial degeneration in the rat is preceded by changes in capillary structure and function. The aim of the present study is to investigate direct effect of gamma ray radiation on activity and apoptosis of cultured rat cardiomyocytes in vitro. Methods: The study was performed using primary cell cultures of cardiomyocytes isolated from hearts of now-born rats. After being cultured for 72h in vitro, cardiomyocytes were irradiated with single dose of 5 Gy, 10 Gy, 20 Gy of gamma ray respectively. At 48h post-irradiation, the concentration of LDH in the supernatant of cell culture was tested using methods introduced by International Federation of clinical chemistry (IFCC), and apoptosis was determined with flow cytometry. The viability of myocytes was determined with crystal violet test and MTT test at 48h and 120h post-irradiation respectively. Results: LDH concentration in the supernatant of cell culture of cardiomyocytes were increased significantly with the irradiation dose augment. Flow cytometry confirmed the induction of apoptosis in response to different gamma ray doses irradiation at 48h after irradiation. The viable cardiomyocytes irradiated by gamma ray were significantly declined at 120h after irradiation compared to un-irradiated cells, however there were no significant difference between two groups at 48h post-irradiation. Dose-effect relationship was demonstrated between cardiomyocyte apoptosis, viability and irradiation dose in the study. Conclusion: The study demonstrates gamma ray radiation can cause direct damage to cultured cardiomyocytes, including inhibiting activity and inducing apoptosis of cardiomyocytes in vitro, which shows dose effect relationship. The mechanism of gamma ray irradiation induced injury to cardiomyocytes should be investigated further. (authors)

  11. Measurement of changes in viscosity in polymers with gamma-ray dose using a differential viscometer

    International Nuclear Information System (INIS)

    Santra, L.; Bhaumik, D.; Roy, S.C.

    1988-01-01

    Although some works on changes in viscosity of liquids with gamma-ray dose have been made near the ''gel point'', very little works have been done bellow this point. Changes in viscosities of different-grade silicone fluids below gel point have been measured using a differential viscometer developed in our laboratory, capable of measuring change in viscosities of two liquids directly. Preliminary results on viscosity changes when irradiated with energetic alpha particles will also be reported [pt

  12. Measurement of changes in viscosity in polymers with gamma-ray dose using a differential viscometer

    International Nuclear Information System (INIS)

    Santra, L.; Bhaumik, D.; Roy, S.C.

    1989-01-01

    Although some works on changes in viscosity of liquids with gamma-ray dose have been made near the 'gel point', very little works have been done below this point. Changes in viscosities of different-grade silicone fluids below gel point have been measured using a differential viscometer developed in our laboratory, capable of measuring change in viscosities of two liquids directly. Preliminary results on viscosity changes when irradiated with energetic alpha particles will also be reported. (orig.)

  13. beta. and. gamma. -comparative dose estimates on Enewetak Atoll

    Energy Technology Data Exchange (ETDEWEB)

    Crase, K.W.; Gudiksen, P.H.; Robison, W.L. (California Univ., Livermore (USA). Lawrence Livermore National Lab.)

    1982-05-01

    Enewetak Atoll in the Pacific is used for atmospheric testing of U.S. nuclear weapons. Beta dose and ..gamma..-ray exposure measurements were made on two islands of the Enewetak Atoll during July-August 1976 to determine the ..beta.. and low energy ..gamma..-contribution to the total external radiation doses to the returning Marshallese. Measurements were made at numerous locations with thermoluminescent dosimeters (TLD), pressurized ionization chambers, portable NaI detectors, and thin-window pancake GM probes. Results of the TLD measurements with and without a ..beta..-attenuator indicate that approx. 29% of the total dose rate at 1 m in air is due to ..beta..- or low energy ..gamma..-contribution. The contribution at any particular site, however, is reduced by vegetation. Integral 30-yr external shallow dose estimates for future inhabitants were made and compared with external dose estimates of a previous large scale radiological survey. Integral 30-yr shallow external dose estimates are 25-50% higher than whole body estimates. Due to the low penetrating ability of the ..beta..'s or low energy ..gamma..'s, however, several remedial actions can be taken to reduce the shallow dose contribution to the total external dose.

  14. Gamma ray astronomy

    International Nuclear Information System (INIS)

    Fichtel, C.E.

    1975-01-01

    The first certain detection of celestial high energy gamma rays came from a satellite experiment flown on the third Orbiting Solar Observatory (OSO-111). A Gamma ray spark chamber telescope with substantively greater sensitivity and angular resolution (a few degrees) flown on the second Small Astronomy Satellite (SAS-II) has now provided a better picture of the gamma ray sky, and particularly the galactic plane and pulsars. This paper will summarize the present picture of gamma ray astronomy as it has developed at this conference from measurements made with experiments carried out on balloons, those remaining on the ground, and ones flown on satellites. (orig.) [de

  15. Influence of gamma rays on the yield of Linum usitatissimum

    International Nuclear Information System (INIS)

    Ghouse, A.K.M.; Abidi, S.H.

    1979-01-01

    The impact of various acute doses of gamma-rays has been studied in an oil yielding Indian variety, Neelum of Linum usitatissimum. It has been found that gamma irradiation brings about an increase in the yield of the crop at lower doses upto 75 krads, while the higher ones like 125 and 150 krads reduce the yield to half. (auth.)

  16. Basics of Gamma Ray Detection

    Energy Technology Data Exchange (ETDEWEB)

    Stinnett, Jacob [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Venkataraman, Ram [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-09-13

    The objective of this training is to explain the origin of x-rays and gamma rays, gamma ray interactions with matter, detectors and electronics used in gamma ray-spectrometry, and features of a gamma-ray spectrum for nuclear material that is safeguarded.

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

    International Nuclear Information System (INIS)

    Tomasova, L.; Smajda, B.

    2008-01-01

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

  18. Dose mapping simulation using the MCNP code for the Syrian gamma irradiation facility and benchmarking

    International Nuclear Information System (INIS)

    Khattab, K.; Boush, M.; Alkassiri, H.

    2013-01-01

    Highlights: • The MCNP4C was used to calculate the gamma ray dose rate spatial distribution in for the SGIF. • Measurement of the gamma ray dose rate spatial distribution using the Chlorobenzene dosimeter was conducted as well. • Good agreements were noticed between the calculated and measured results. • The maximum relative differences were less than 7%, 4% and 4% in the x, y and z directions respectively. - Abstract: A three dimensional model for the Syrian gamma irradiation facility (SGIF) is developed in this paper to calculate the gamma ray dose rate spatial distribution in the irradiation room at the 60 Co source board using the MCNP-4C code. Measurement of the gamma ray dose rate spatial distribution using the Chlorobenzene dosimeter is conducted as well to compare the calculated and measured results. Good agreements are noticed between the calculated and measured results with maximum relative differences less than 7%, 4% and 4% in the x, y and z directions respectively. This agreement indicates that the established model is an accurate representation of the SGIF and can be used in the future to make the calculation design for a new irradiation facility

  19. Method of incident low-energy gamma-ray direction reconstruction in the GAMMA-400 gamma-ray space telescope

    International Nuclear Information System (INIS)

    Kheymits, M D; Leonov, A A; Zverev, V G; Galper, A M; Arkhangelskaya, I V; Arkhangelskiy, A I; Yurkin, Yu T; Bakaldin, A V; Suchkov, S I; Topchiev, N P; Dalkarov, O D

    2016-01-01

    The GAMMA-400 gamma-ray space-based telescope has as its main goals to measure cosmic γ-ray fluxes and the electron-positron cosmic-ray component produced, theoretically, in dark-matter-particles decay or annihilation processes, to search for discrete γ-ray sources and study them in detail, to examine the energy spectra of diffuse γ-rays — both galactic and extragalactic — and to study gamma-ray bursts (GRBs) and γ-rays from the active Sun. Scientific goals of GAMMA-400 telescope require fine angular resolution. The telescope is of a pair-production type. In the converter-tracker, the incident gamma-ray photon converts into electron-positron pair in the tungsten layer and then the tracks are detected by silicon- strip position-sensitive detectors. Multiple scattering processes become a significant obstacle in the incident-gamma direction reconstruction for energies below several gigaelectronvolts. The method of utilising this process to improve the resolution is proposed in the presented work. (paper)

  20. Dose-modifying factors for skin ulceration in mouse legs exposed to gamma rays

    International Nuclear Information System (INIS)

    Masuda, Kouji; Miyoshi, Makoto; Uehara, Satoru; Omagari, Junichi; Withers, H.R.

    1996-01-01

    To assess the dose-modifying factors for skin ulceration, the hind legs of mice were irradiated using gamma-rays of various doses in single exposures. The skin ulceration began to occur 2 months after irradiation, after early skin reactions such as wet desquamation, had healed completely. No new skin ulceration was observed more than 8 months after irradiation even though the observations were continued until 12 months post-irradiation. The ulceration dose 50 (UD50), a dose required to produce skin ulceration in from 2 to 8 months in 50% of the tested animals, was calculated for each treatment schedule. The preliminary shaving procedure reduced the UD50 dose to 0.85 that of the untreated controls. The ventral aspect of the hind leg was more radioresistant to single-dose irradiation than was to the dorsal aspect. The UD50 for the ventral aspect was 1.29 times that for the dorsal aspect when the skin had been previously shaved, and 1.46 times that for the unshaved control legs. The UD50 was 7 and 14% larger when mice were kept in the dorsal rather than the abdominal position during irradiation, for the preliminarily shaved and unshaved skin, respectively. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-03-01

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

  2. Estimation of the shielding ability of a tungsten functional paper for diagnostic x-rays and gamma rays.

    Science.gov (United States)

    Monzen, Hajime; Kanno, Ikuo; Fujimoto, Takahiro; Hiraoka, Masahiro

    2017-09-01

    Tungsten functional paper (TFP) is a novel paper-based radiation-shielding material. We measured the shielding ability of TFP against x-rays and gamma rays. The TFP was supplied in 0.3-mm-thick sheets that contained 80% tungsten powder and 20% cellulose (C 6 H 10 O 5 ) by mass. In dose measurements for x-rays (60, 80, 100, and 120 kVp), we measured doses after through 1, 2, 3, 5, 10, and 12 TFP sheets, as well as 0.3 and 0.5 mm of lead. In lead equivalence measurements, we measured doses after through 2 and 10 TFP sheets for x-rays (100 and 150 kVp), and 0, 7, 10, 20, and 30 TFP sheets for gamma rays from cesium-137 source (662 keV). And then, the lead equivalent thicknesses of TFP were determined by comparison with doses after through standard lead plates (purity >99.9%). Additionally, we evaluated uniformity of the transmitted dose by TFP with a computed radiography image plate for 50 kVp x-rays. A single TFP sheet was found to have a shielding ability of 65%, 53%, 48%, and 46% for x-rays (60, 80, 100, and 120 kVp), respectively. The lead equivalent thicknesses of two TFP sheets were 0.10 ± 0.02, 0.09 ± 0.02 mmPb, and of ten TFP sheets were 0.48 ± 0.02 and 0.51 ± 0.02 mmPb for 100 and 150 kVp x-rays, respectively. The lead equivalent thicknesses of 7, 10, 20, and 30 sheets of TFP for gamma rays from cesium-137 source were estimated as 0.28, 0.43, 0.91, and 1.50 mmPb with an error of ± 0.01 mm. One TFP sheet had nonuniformity, however, seven TFP sheets provided complete shielding for 50 kVp x-rays. TFP has adequate radiation shielding ability for x-rays and gamma rays within the energy range used in diagnostic imaging field. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  3. Distribution of gamma-ray dose rate in Fukushima prefecture by a car-borne survey method

    International Nuclear Information System (INIS)

    Sugihara, Shinji; Momoshima, Noriyuki; Maekawa, Akihiro; Ichikawa, Ryohei; Kawamura, Hidehisa

    2013-01-01

    The Tohoku Pacific Earthquake and Tsunami on March 11, 2011, caused severe damage to the TEPCO Fukushima Dai-ichi NPP. This was followed by a nuclear accident at an unprecedented scale, and huge amounts of radioactive material were released into the environment. The distributions of the gamma-ray dose rate in Fukushima prefecture were measured using a NaI(Tl) scintillation survey meter as part of a car-borne survey method on April 18-21, June 20-22, October 18-21, 2011, and on April 9-11 and July 30 - August 1, 2012. The dose rate near TEPCO Fukushima Dai-ichi NPP and at Iitate-mura, Fukushima-city was high (1 to >30 μSv/h). (author)

  4. The transport of neutrons and gamma-rays in the air

    International Nuclear Information System (INIS)

    Adamski, J.

    1980-01-01

    The transport of neutrons and gamma rays in the infinite homogeneous air has been investigated. For the calculations has been used the Multigroup One Dimensional Discrete Ordinates Transport Code ANISN-W. The calculations have been performed for three types of neutron sources. The neutrons and gamma ray doses in the air have been analyzed, and comparison to the other authors' results has been given. (author)

  5. Gamma-Ray Dosimetry System Using Radiation-Resistant Optical Fibers and a Luminescent Material

    International Nuclear Information System (INIS)

    Toh, K.; Nakamura, T.; Yamagishi, H.; Sakasai, K.; Soyama, K.; Shikama, T.; Nagata, S.

    2013-06-01

    Gamma-ray dosimetry system using radiation-resistant optical fibers and a luminescent material was developed for use in a damaged Fukushima Dai-ichi nuclear power plant. The system was designed to be compact and unnecessary of an external supply of electricity to a radiation sensor head with a contaminated working environment and restricted through-holes to a measurement point in the damaged reactor. The system can detect a gamma-ray dose rate at a measurement point using a couple of optical fibers and a luminescent material with a coincidence method. This system demonstrated a linear response with respect to the gamma-ray dose rate from 0.5 mGy/h to 0.1 Gy/h and the system had a capability to measure the dose rate of more than 10 2 Gy/h. (authors)

  6. Efficiency and effectiveness of gamma rays and sodium azide in Sesbania cannabina Poir

    International Nuclear Information System (INIS)

    Kumar, G.; Srivastava, N.

    2013-01-01

    Mutagenic effectiveness and efficiency is an important factor for the selection of a mutagen for a mutation breeding program. Mutagenic effectiveness is a measure of the frequency of mutations induced by a unit mutagen dose, while mutagenic efficiency is a measure of the proportion of mutations in relation to undesirable changes such as lethality, sterility, meiotic aberrations etc. The present study envisages the mutagenic effectiveness and efficiency of individual and combined treatments of chemical and physical mutagens i.e. sodium azide (individual), gamma rays (individual) and sodium azide + gamma ray (combined). For the individual treatment of sodium azide, the seeds of the Sesbania cannabina variety ND-1 were treated with 0.5% solution of sodium azide (SA) for four different time durations, i.e. 3, 5, 7, and 9 h, and for the individual treatment of gamma rays, dry and healthy seeds were treated with 20, 40, 60, and 80 Kr doses of gamma rays. For the combined treatment, the seeds were exposed to four different doses of gamma rays (20, 40, 60, and 80 Kr) and after irradiation seeds were treated with 0.5% solution of sodium azide for 3 h. After treatment, seeds subjected to individual and combined treatment were sown in randomized block design to raise the M 1 generation and a study was conducted on germination percentage, survival percentage, pollen fertility percentage, and chromosomal aberrations at different doses of the individual and combined treatments. (author)

  7. X-ray echoes from gamma-ray bursts

    International Nuclear Information System (INIS)

    Dermer, C.D.; Hurley, K.C.; Hartmann, D.H.

    1991-01-01

    The identification of an echo of reflected radiation in time histories of gamma-ray burst spectra can provide important information about the existence of binary companions or accretion disks in gamma-ray burst systems. Because of the nature of Compton scattering, the spectrum of the echo will be attenuated at gamma-ray energies compared with the spectrum of the primary burst emission. The expected temporal and spectral signatures of the echo and a search for such echoes are described, and implications for gamma-ray burst models are discussed. 35 refs

  8. Committed effective dose determination in cereal flours by gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Scheibel, Viviane

    2006-01-01

    The health impact from radionuclides ingestion of foodstuffs was evaluated by the committed effective doses determined in commercial samples of South-Brazilian cereal flours (soy, wheat, corn, manioc, rye, oat, barley and rice flour). The radioactivity traces of 228 Th, 228 Ra, 226 Ra, 40 K, 7 Be and 137 Cs were measured by gamma-ray spectrometry employing a 66% relative efficiency HPGe detector. The energy resolution for the 1332.46 keV line of 60 Co was 2.03 keV. The committed effective doses were calculated with the activities analyzed in the present flour samples, the foodstuff rates of consumption (Brazilian Institute of Geography and Statistics) and the ingestion dose coefficients (International Commission of Radiological Protection). The reliability median activities were verified with χ 2 tests, assuring the fittings quality. The highest concentration levels of 228 Th and 40 K were 3.5 ± 0.4 and 1469 ± 17 Bq.kg -1 for soy flour, respectively, with 95% of confidence level. The lower limit of detection for 137 Cs ranged from 0.04 to 0.4 Bq.kg -1 . The highest committed effective dose was 0.36 μSv.y -1 for 228 Ra in manioc flour (adults). All committed effective doses determined at the present work were lower than the UNSCEAR limits of 140 μSv.y -1 and much lower than the ICRP (1991) limits of 1 mSv.y -1 , for general public. There are few literature references for natural and artificial radionuclides in foodstuffs and mainly for committed effective doses. This work brings the barley flour data, which is not present at the literature and 7 Be data which is not encountered in foodstuffs at the literature, besides all the other flours data information about activities and committed effective doses. (author)

  9. Absorbed dose to water comparison between NE 2561 and NE 2671 chambers using IAEA, HPA and NACP protocols for gamma ray beam

    International Nuclear Information System (INIS)

    Mohd Taufik Dolah; Noriah Mod Ali; Taiman Kadni

    2002-01-01

    The aim of this study to evaluate the performance of NE 2571 chamber in comparison with NE 2561 chamber in determination of the absorbed dose to water in gamma ray beam. In this study NE 2561 is taking as a reference standard chamber while NE 2571 as a working standard. Irradiation of chamber (alternately) was performed at a reference depth, 5 cm, inside the IAEA water phantom. Both chambers were exposed to 13 difference exposures of gamma rays. The values of absorbed dose to water were then determined using IAEA, HPA and NACP protocols. Deviations of absorbed dose determined by NE 2561 and NE 2571 were calculated for each protocol. result obtained in terms of [protocol, μ (mean deviation) ± σ s e (standard error)] were (IAEA, 1.12 ± 0.04], [HPA, 0.09 ± 0.04], and [NCP, 0.09 ± 0.04]. It can be concluded that NE 2571 shown acceptable performance as it is within acceptable limit ± 3%. (Author)

  10. Radiation mutagenesis in lavender. I.Dose and emissive power as affecting the radiosensitivity of lavender seeds in gamma-ray treatment

    International Nuclear Information System (INIS)

    Tsvetkov, R.

    1977-01-01

    The radiosensitivity has been investigated of dormant seeds of the widely distributed aboriginal Hemus and Karlovo varieties and of the Soviet Stepnaya lavender variety in treatment with gamma rays using 60 Co. Doses within 1 to 100 kRad are applied at different emissive power of the emitter. Both irradiated and nonirradiated control seeds are gibberellic acid treated. The dynamics of seed sprouting is followed up. The number of survived plants and peculiarities of their growth are registered. The radiosensitivity of Lavandula vera D.C. seeds is modified by the emissive power in equal doses applied. Stepnaya variety showed highest resistance, followed by Karlovo and Hemus varieties. Doses are ascertained with a stimulating, inhibiting, semilethal and lethal effect in regard to the separate varietoes. Both stimulation and injuring prove to be of saltatory character. The radiation injuring of doses with an inhibitory, semilethal and lethal effect positively correlate with the dose of all tested emissive powers of the gamma-emitter. (author)

  11. The Gamma-ray Sky with Fermi

    Science.gov (United States)

    Thompson, David

    2012-01-01

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

  12. Applied gamma-ray spectrometry

    CERN Document Server

    Dams, R; Crouthamel, Carl E

    1970-01-01

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

  13. Removal of endocrine disruptors PAEs in drinking water by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Zhao Yongfu; Zheng Zheng; Zheng Binguo; Wang Changbao; Li Lili

    2012-01-01

    Phthalic acid esters (PAEs) belong to environmental endocrine disruptor. The dimethyl phthalate (DMP), diethyl phthalate (DEP) and di-n-butyl phthalate (DBP) were selected for the radiation study. The removal efficiencies of DMP, DEP and DBP in drinking water by gamma-ray irradiation are discussed. The results show that these PAEs could be efficiently removed by gamma-ray irradiation. The removal efficiencies of DMP, DEP and DBP (12 mg/L) in aqueous solutions by 0.8 kGy gamma-ray treatment were 96.6%, 94.5% and 86.2%. The absorbed dose needed for the removal of total carbon in aqueous solutions was much larger than the doses for PAEs degradation. When 2 kGy was selected, the removal efficiencies of TC for DMP, DEP and DBP were only 23.6%, 14.3% and 12.9%. The study results also show that the radiation degradation reaction of PAEs should be divided into two stages: low dose addition reaction and high dose ring-opening reaction. This study is of significance in the disposal of micro-polluted drinking water. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

    Alya, G; Shamma, M; Sharabi, N [Atomic Energy Commission, Damascus (Syrian Arab Republic), Dept. of Molecular Biology and Biotechnology

    2007-03-15

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

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

    International Nuclear Information System (INIS)

    Alya, G.; Shamma, M.; Sharabi, N.

    2007-03-01

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

  16. Gamma-ray dose rate surveys help investigating century-scale beach ridge progradation in the wave-dominated Catumbela delta (Angola)

    Science.gov (United States)

    Dinis, Pedro A.; Pereira, Alcides C.; Quinzeca, Domingos; Jombi, Domingos

    2017-10-01

    A strandplain at the downdrift side of the wave-dominated Catumbela delta (Angola) includes distinguishable deposits with very high natural radioactivity (up to 0.44 microSv/hour). In order to establish the geometry of these sedimentary units and understand their genetic processes, dose rate surveys were performed with the portable equipment Rados RDS-40WE. In addition, grain-size distribution, heavy-mineral composition and gamma-ray mass spectra of the high dose rate deposits were analysed. High dose rate values are found in ribbon units aligned parallel to the shoreline, which are a few tens of meters wide and up to approximately 3 km long. These units reflect the concentration of Th-bearing grains in coastal deposits enriched in heavy minerals. An integrated analysis of the high dose rate ribbons in GIS environment with aerial photography and topographic maps suggests that parts of the high dose rate units formed during the last two centuries may be related with the erosion of older shoreline deposits, due to updrift displacements of the Catumbela river outlet and recycling of shoreline accumulations with downdrift deposition. Simple gamma-ray surveys carried out with a portable detector can unravel depositional units characterised by significant enrichment in heavy-mineral grains that are likely to correspond to key events in the evolution of wave-dominated accumulations. The location of such deposits should be taken into account when planning future work using more expensive or time-consuming techniques.

  17. In vivo measurement by thermoluminescence of the gamma ray radiation dose to the uterus delivered during 131I therapy of Basedow's disease

    International Nuclear Information System (INIS)

    Philippon, B.; Briere, J.

    1977-01-01

    131 I is often the therapy of choice for BASEDOW's disease. The determination of radiation dose to the gonads from a therapeutic dose of 131 I is therefore of importance and the accuracy of radiation dose calculation is uncertain because of the numerous biological variables involved. The dose to the uterus was directly measured in 20 volonteers with Basedow's disease using a thermoluminescent dosimeter of lithium fluoride and calcium dysprosium sulfate, attached to a copper intrauterine contraceptive device. The dosimeters were inserted at the time of administration of 131 I and were retreived one month later. By this method, the dose to the uterus from gamma rays only was measured and a gamma ray dose equal to the dose to the uterus, was assumed to the ovaries. In vivo experimental results were compared with the values calculated using the specific absorbed fractions (PHI (r 2 - r 1 ) determined by SNYDER. In the calculations, the morphology of the patient, in particular the distance from thyroid to uterus was taken into account. The in vivo measurements have also been compared with direct in vivo measurements using phantoms. In vivo measurements indicate that the average dose to the uterus and ovaries is of the order of 1 rad per 10 mCi concentrated in the thyroid gland. These figures are below the generally accepted maximum admissible dose to the gonads of 10 rems [fr

  18. Measurement of gamma ray flux within the containment building at the first unit of Kori nuclear power station

    Energy Technology Data Exchange (ETDEWEB)

    Kim, T. W.; Kim, K. D.; Yoon, C. H.; Han, J. M.; Hu, Y. H. [Korea Hydraulic and Nuclear Power Company, Taejon (Korea, Republic of)

    2004-07-01

    To evaluate gamma ray dose response of GM counter being used for monitoring of gamma ray field in nuclear power plants, gamma ray energy spectra and fluxes were obtained for three positions at the unit 1 of the Kori nuclear power station. By applying the response values of Eberline's E112B survey meter to the results, the doses represented on the survey meter were overestimated from 1.31 to 1.37 times when compared to the real doses for these three positions.

  19. Optical observations of Gamma-Ray Bursts

    International Nuclear Information System (INIS)

    Hjorth, J.; Pian, E.; Fynbo, J.P.U.

    2004-01-01

    We briefly review the status and recent progress in the field of optical observations of gamma-ray burst afterglows. We will focus on the fundamental observational evidence for the relationship between gamma-ray bursts and the final evolutionary phases of massive stars. In particular, we will address (i) gamma-ray burst host galaxies, (ii) optically dark gamma-ray burst afterglows, (iii) the gamma-ray burst-supernova connection, and (iv) the relation between X-ray flashes, gamma-ray bursts, and supernovae

  20. beta- and gamma-Comparative dose estimates on Eniwetok Atoll

    Energy Technology Data Exchange (ETDEWEB)

    Crase, K.W.; Gudiksen, P.H.; Robison, W.L.

    1982-05-01

    Eniwetok Atoll is one of the Pacific atolls used for atmospheric testing of U.S. nuclear weapons. Beta dose and gamma-ray exposure measurements were made on two islands of the Eniwetok Atoll during July-August 1976 to determine the beta and low energy gamma-contribution to the total external radiation doses to the returning Marshallese. Measurements were made at numerous locations with thermoluminescent dosimeters (TLD), pressurized ionization chambers, portable NaI detectors, and thin-window pancake GM probes. Results of the TLD measurements with and without a beta-attenuator indicate that approx. 29% of the total dose rate at 1 m in air is due to beta- or low energy gamma-contribution. The contribution at any particular site, however, is somewhat dependent on ground cover, since a minimal amount of vegetation will reduce it significantly from that over bare soil, but thick stands of vegetation have little effect on any further reductions. Integral 30-yr external shallow dose estimates for future inhabitants were made and compared with external dose estimates of a previous large scale radiological survey (En73). Integral 30-yr shallow external dose estimates are 25-50% higher than whole body estimates. Due to the low penetrating ability of the beta's or low energy gamma's, however, several remedial actions can be taken to reduce the shallow dose contribution to the total external dose.

  1. Determination the lethal dose of ascaris lumbricoides ova by gamma irradiation

    International Nuclear Information System (INIS)

    Shamma, M.; Al-Adawi, M.; Sharabi, N.

    2002-11-01

    The lethal gamma irradiation dose of ascaris lumbricoides which collected from Damascus Sewage water Plant was determined. Ascaris lumbricoides ova were treated with several gamma irradiation doses with (0.1, 0.2, 0.3, 0.4,...and 1.5 KGy). No morphological changes were observed on the eggs when directly examined microscopically after irradiation. However after two weeks of incubation at 37 degree centigrade the cell contents of the eggs which irradiated with 0.5 KGy and beyond were fragmented and scattered in the whole eggs and no larvae were observed after eight weeks of incubation. It is concluded that the dose 0.5 my be considered as the dose of choice if sewage water is to be treated by gamma rays. (author)

  2. Determination the lethal dose of ascaris lumbricoides ova by gamma irradiation

    CERN Document Server

    Shamma, M A; Sharabi, N

    2002-01-01

    The lethal gamma irradiation dose of ascaris lumbricoides which collected from Damascus Sewage water Plant was determined. Ascaris lumbricoides ova were treated with several gamma irradiation doses with (0.1, 0.2, 0.3, 0.4,...and 1.5 KGy). No morphological changes were observed on the eggs when directly examined microscopically after irradiation. However after two weeks of incubation at 37 degree centigrade the cell contents of the eggs which irradiated with 0.5 KGy and beyond were fragmented and scattered in the whole eggs and no larvae were observed after eight weeks of incubation. It is concluded that the dose 0.5 my be considered as the dose of choice if sewage water is to be treated by gamma rays.

  3. The Gamma-ray Universe through Fermi

    Science.gov (United States)

    Thompson, David J.

    2012-01-01

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

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

    International Nuclear Information System (INIS)

    Kraljevic, P.; Vilic, M.; Miljanic, S.; Simpraga, M.

    2005-01-01

    In our earlier studies chickens hatched from eggs irradiated with 0.15 Gy gamma rays before incubation showed a significantly higher growth than controls during the fattening period (1-42 days). The activity of aspartate-aminotransferase (AST), alanine-aminotransferase (ALT) and plasma glucose in the same chickens were also significantly higher. These results suggested that low-dose gamma-radiation stimulated certain metabolic processes in chickens hatched from eggs irradiated before incubation. The goal of this study was to determine the effects of low-dose ionising radiation on AST and ALT activity in the blood plasma of chickens hatched from eggs irradiated during incubation. The eggs of heavy breeding chickens (Avian, line 34) were exposed to 0.15 Gy of gamma-radiation (6 0C o) on the seventh day of incubation, i.e. at the time when the organogenesis in chickens is completed. The control group of chickens hatched from non-irradiated eggs. All other conditions were the same for both groups. After hatching, blood samples were taken from the wing vein on days 1, 3, 5, 7, 10, 20, 32 and 42. The activity of both enzymes was determined spectrophotometrically using Boehringer Mannheim GmbH optimised kits. On day 10, AST and ALT activity were significantly higher in the blood plasma of chickens hatched from irradiated eggs, but it significantly dropped for both enzymes on day 20. Our results indicate that exposure of eggs to low-dose gamma-radiation on the seventh day of incubation affects AST and ALT activity in the blood plasma of chickens hatched from irradiated eggs. However, this effect is somewhat different from the effects of egg exposure to low-dose gamma radiation before incubation.(author)

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

    International Nuclear Information System (INIS)

    Ahmed, El-Sayed S.

    1976-01-01

    Infested and non-infested dry date fruits (Phonex dactylifera), Abrimi variety (9.2% moisture), with Ephestia cautella Walker were irradiated for 0, 15, 20 and 40 Krad gamma ray doses emitted from Co-60 source with 1.36 x 10-rad/h. as a dose rate. Irradiated fruits were stored at room temperature, at 20-25 0 C and 85-95% R.H., in packages to avoid reinfestation. A dose of 20 Krad is 100 percent effective in preventing the emergency of eggs, larva, and pupae in fruits as reflected by zero per cent emergency count for live adults. Also, this dose was found to be lethal for adult stage of the insect. On the other hand, 2 Krad dose does not produce significant changes in the nutritional qualities of fruits, as measured by chemical analytical means for carbohydrates, protein and amino acids, directly after irradiation as well as at 2, 4 and 6 months storage. The triangular tests show that irradiation treatments even with 4 Krad exerted no determinal effect upon the sensory qualities of stored irradiated date fruits. These results point out the feasibility of applying gamma irradiation, 20 Krad, as disinfestation technique against Ephestia cautella Walker in dry date fruits without exerting any effect on the nutritional value

  6. Organ doses as a function of body weight for environmental gamma rays

    International Nuclear Information System (INIS)

    Saito, Kimiaki; Petoussi, N.; Zankl, M.; Veit, R.; Jacob, P.; Drexler, G.

    1991-01-01

    The organ doses for γ rays from typical environmental sources were determined with Monte Carlo calculations using anthropomorphic phantoms having different body sizes. It has been suggested that body weight is the predominant factor influencing organ doses for environmental γ rays, regardless of sex and age. A weight function expressing organ doses for environmental γ rays was introduced. This function fitted well with the organ doses calculated using the different phantoms. The function coefficients were determined mathematically with the least squares method. On the assumption that this function was applicable to organ doses for human bodies with diverse characteristics, the variances in organ doses due to race, sex, age and difference in body weight of adults were investigated. The variations of organ doses due to race and sex were not significant. Differences in body weight were found to alter organ doses by a maximum of 10% for γ rays over 100 keV, and 20% for low-energy γ rays. The doses for organs located deep inside a body, such as ovaries, differed between a newborn baby and an adult by a maximum factor of 2 to 3. For γ rays over 100 keV, the variation was within a factor of 2 for all organs. The organ doses for adolescents more than 12 years agreed within 15% with those of the average adult. (author)

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

    International Nuclear Information System (INIS)

    Xiao-Ming, Jin; Ru-Yu, Fan; Wei, Chen; Dong-Sheng, Lin; Shan-Chao, Yang; Xiao-Yan, Bai; Yan, Liu; Xiao-Qiang, Guo; Gui-Zhen, Wang

    2010-01-01

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

  8. Somatic mutation frequencies in the stamen hairs of stable and mutable clones of Tradescantia after acute gamma-ray treatments with small doses

    International Nuclear Information System (INIS)

    Ichikawa, Sadao; Takahashi, C.S.

    1977-01-01

    Young inflorescences of two different Tradescantia clones heterozygous for flower and stamen-hair color, one stable (KU 9) and the other spontaneously mutable (KU 20), were irradiated acutely with small doses (approx. 3 to 50 R) of 60 Co gamma-rays. Somatic mutation frequencies from blue to pink in the stamen hairs scored on post-irradiation days 10 to 16 increased essentially linearly with increasing gamma-ray dose in both clones. Despite about a 5-fold difference in spontaneous mutation frequency per hair found between the two clones, the dose-response curves of pink mutations determined were similar to each other, giving average mutation frequencies of 1.51 and 1.41 pink-mutant events per 1000 hairs per R for KU 9 and KU 20, respectively. These frequencies are comparable to earlier results obtained from acute irradiation treatments of other clones with higher doses. The doubling dose of pink mutation (the radiation dose making the mutation frequency double the spontaneous level) was calculated to be 2.09 R for KU 9, and this low doubling dose must be given full attention. On the other hand, the doubling dose for KU 20 (calculated to be 10.4 R) is of questionable value, being greatly subject to change because of the diversely variable spontaneous mutation frequency of this clone

  9. Extra-light gamma-ray imager for safeguards and homeland security

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Oleg P.; Semin, Ilya A.; Potapov, Victor N.; Stepanov, Vyacheslav E. [National Research Centre Kurchatov Institute, Moscow, 123182, (Russian Federation)

    2015-07-01

    Gamma-ray imaging is the most important way to identify unknown gamma-ray emitting objects in decommissioning, security, overcoming accidents. Over the past two decades a system for producing of gamma images in these conditions became more or less portable devices. But in recent years these systems have become the hand-held devices. This is very important, especially in emergency situations, and measurements for safety reasons. We describe the first integrated hand-held instrument for emergency and security applications. The device is based on the coded aperture image formation, position sensitive gamma-ray (X-ray) detector Medipix2 (detectors produces by X-ray Imaging Europe) and tablet computer. The development was aimed at creating a very low weight system with high angular resolution. We present some sample gamma-ray images by camera. Main estimated parameters of the system are the following. The field of view video channel ∼ 490 deg. The field of view gamma channel ∼ 300 deg. The sensitivity of the system with a hexagonal mask for the source of Cs-137 (Eg = 662 keV), is in units of dose D ∼ 100 mR. This option is less then order of magnitude worse than for the heavy, non-hand-held systems (e.g., gamma-camera Cartogam, by Canberra.) The angular resolution of the gamma channel for the sources of Cs-137 (Eg = 662 keV) is about 1.20 deg. (authors)

  10. Lunar based gamma ray astronomy

    International Nuclear Information System (INIS)

    Haymes, R.C.

    1985-01-01

    Gamma ray astronomy represents the study of the universe on the basis of the electromagnetic radiation with the highest energy. Gamma ray astronomy provides a crucial tool for the understanding of astronomical phenomena, taking into account nucleosynthesis in supernovae, black holes, active galaxies, quasars, the sources of cosmic rays, neutron stars, and matter-antimatter annihilation. Difficulties concerning the conduction of studies by gamma ray astronomy are related to the necessity to perform such studies far from earth because the atmosphere is a source of gamma rays. Studies involving the use of gamma ray instruments in earth orbit have been conducted, and more gamma ray astronomy observations are planned for the future. Imperfections of studies conducted in low earth orbit could be overcome by estalishing an observatory on the moon which represents a satellite orbiting at 60 earth radii. Details concerning such an observatory are discussed. 5 references

  11. Research on self-powered detectors for gamma-ray monitoring

    International Nuclear Information System (INIS)

    Cho, S.W.; Lee, Y.J.

    1984-01-01

    Self-powered neutron detectors are used extensively in power reactors both for flux mapping and for power control and over-power protection, because of their small size, ruggedness and simplicity. But they have a few disadvantages such as high burn-up rate and background signal produced by the gamma-rays from the reactor itself. In order to overcome these disadvantages and to achieve a better understanding of gamma-ray effects of self-power detectors, a new type of self-powered detectors was designed and fabricated by the author,and experiments have carried out in the 10kCi sup(60)Co gamma irradiation facility in Korea Advanced Energy Research Institute. The configuration of the new type detectors is not of coaxial type but of paralled plate in order to obtain directional effects of gamma-ray incidence. Detector materials and dimensions are so chosen that the output current signal is large enough to be detected using some commercial measuring divice even at low dose rate and the contribution of the lead cable to the total signal is negligibly small. The results are 1)sensitivity is depended primarily on the materials of the insulator, 2)output signal has a good linearity to gamma dose rate, 3) response of detectors is prompt, but not perfect, 4) critical thickness for satusation of the output current is thinner than the range of photoelectron in the materials. (Author)

  12. Research on self-powered detectors for gamma-ray monitoring

    International Nuclear Information System (INIS)

    Cho, S.W.

    1983-01-01

    Self-powered neutron detectors are used extensively in power reactors both for flux mapping and for power control and over-power protection, because of their small size, ruggedness and simplicity. But they have a few disadvantages such as high burn-up rate and background signal produced by the gamma-rays from the reactor itself. In order to overcome these disadvantages and to achieve a better understanding of gamma-ray effects of self-powered detectors, a new type of self-powered detectors was designed and fabricated by the author, and experiments have been carried out in the 10kCi sup(60)Co gamma irradiation facility in Korea Advanced Energy Research Institute. The configuration of the new type detectors is not of coaxial type but of paralled plate in order to obtain directional effects of gamma-ray incidence. Detector materials and dimensions are so chosen that the output current signal is large enough to be detected using some commercial measuring divice even at low dose rate and the contribution of the lead cable to the totel signal is negligibly small. The results are 1) sensitivity is depended primarily on the materials of the insulator, 2) output signal has a good linearity to gamma dose rate, 3) response of detectors is prompt, but not perfect, 4) critical thickness for satusation of the output current is thinner than the range of photoelectron in the materials. (Author) πT

  13. Compton Gamma-Ray Observatory

    Science.gov (United States)

    1991-01-01

    This photograph shows the Compton Gamma-Ray Observatory (GRO) being deployed by the Remote Manipulator System (RMS) arm aboard the Space Shuttle Atlantis during the STS-37 mission in April 1991. The GRO reentered Earth atmosphere and ended its successful mission in June 2000. For nearly 9 years, the GRO Burst and Transient Source Experiment (BATSE), designed and built by the Marshall Space Flight Center (MSFC), kept an unblinking watch on the universe to alert scientists to the invisible, mysterious gamma-ray bursts that had puzzled them for decades. By studying gamma-rays from objects like black holes, pulsars, quasars, neutron stars, and other exotic objects, scientists could discover clues to the birth, evolution, and death of stars, galaxies, and the universe. The gamma-ray instrument was one of four major science instruments aboard the Compton. It consisted of eight detectors, or modules, located at each corner of the rectangular satellite to simultaneously scan the entire universe for bursts of gamma-rays ranging in duration from fractions of a second to minutes. In January 1999, the instrument, via the Internet, cued a computer-controlled telescope at Las Alamos National Laboratory in Los Alamos, New Mexico, within 20 seconds of registering a burst. With this capability, the gamma-ray experiment came to serve as a gamma-ray burst alert for the Hubble Space Telescope, the Chandra X-Ray Observatory, and major gound-based observatories around the world. Thirty-seven universities, observatories, and NASA centers in 19 states, and 11 more institutions in Europe and Russia, participated in the BATSE science program.

  14. Aging of magnesium stearate under high doses gamma irradiation and oxidative conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lebeau, D.; Beuvier, L.; Cornaton, M. [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); Miserque, F. [CEA, DEN, DPC, SCCME, LECA, F-91191 Gif-sur-Yvette (France); Tabarant, M. [CEA, DEN, DPC, SEARS, LISL, F-91191 Gif-sur-Yvette (France); Esnouf, S. [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); Ferry, M., E-mail: muriel.ferry@cea.fr [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France)

    2015-05-15

    Highlights: • Magnesium stearate was radio-oxidized at very high doses using gamma-rays. • H{sub 2} emission was estimated as a function of the integrated dose. • Modifications in the organic solid were followed as a function of the integrated dose. • A non-exhaustive degradation mechanism of magnesium stearate was proposed. - Abstract: In nuclear waste packages conditioning processes, magnesium stearate is widely used because of its high lubricating properties. For safety purposes, the radiolytic degradation of these organic materials has to be better understood to be able to predict their aging in repository conditions. This study reports the radiolytic degradation of magnesium stearate, using gamma-rays at room temperature and under air. Modifications were followed using different analytical tools (XPS, ATR-FTIR, ICP-AES, ATG and mass spectrometry). It has been observed that molecules mainly formed up to 1000 kGy of gamma irradiation dose under radio-oxidation are alkanes, hydroperoxides, double bonds in the aliphatic chain, carboxylates with aliphatic chain shorter than the one of stearate and ketones. At a dose of 4000 kGy, dicarboxylic acids are observed: the formation of these molecules needs a dose of at least 1000 kGy to be created under radio-oxidation. These observations allow us to propose a non-exhaustive degradation mechanism of magnesium stearate under gamma-irradiation at room temperature and under air.

  15. X-Ray-Driven Gamma Emission

    International Nuclear Information System (INIS)

    Carroll, J. J.; Karamian, S. A.; Rivlin, L. A.; Zadernovsky, A. A.

    2001-01-01

    X-ray-driven gamma emission describes processes that may release nuclear energy in a 'clean' way, as bursts of incoherent or coherent gamma rays without the production of radioactive by-products. Over the past decade, studies in this area, as a part of the larger field of quantum nucleonics, have gained tremendous momentum. Since 1987 it has been established that photons could trigger gamma emission from a long-lived metastable nuclear excited state of one nuclide and it appears likely that triggering in other isotopes will be demonstrated conclusively in the near future. With these experimental results have come new proposals for the creation of collective and avalanche-like incoherent gamma-ray bursts and even for the ultimate light source, a gamma-ray laser. Obviously, many applications would benefit from controlled bursts of gamma radiation, whether coherent or not. This paper reviews the experimental results and concepts for the production of gamma rays, driven by externally produced X-rays

  16. GammaModeler 3-D gamma-ray imaging technology

    International Nuclear Information System (INIS)

    2000-01-01

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

  17. Extragalactic Gamma-Ray Astrophysics

    CERN Multimedia

    CERN. Geneva

    2016-01-01

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

  18. Studies on the influences of. gamma. -ray irradiation upon food additives, (8). Influences of. gamma. -ray irradiation on polyphosphates in aqueous solution and in 'kamaboko'

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, M; Ishio, S [Kyushu Univ., Fukuoka (Japan). Faculty of Agriculture

    1981-08-01

    The effect of ..gamma..-ray irradiation on polyphosphates in aqueous solution and in ''kamaboko'' was investigated to evaluate the rate of decomposition and to examine the safety of the decomposed products. Tripolyphosphate, pyrophosphate and o-phosphate in aqueous solution were very stable against ..gamma..-ray irradiation, respectively. Tripolyphosphate added to ''surimi'' (minced and washed flesh of Alaska Pollack) completely changed to o-phosphate during the period of processing ''kamaboko'', but pyrophosphate was retained. Pyrophosphate content in ''kamaboko'' decreased in proportion to the dose of ..gamma..-ray. Decreased pyrophosphate was presumed to change into such products as insolubles which can not be extracted with 6% per chloric acid solution. Both tripolyphosphate and pyrophosphate changed enzymatically to o-phosphate. The activity of exopolyphosphatase in ''surimi'' was still retained. Polyphosphates added to ''surimi'' changed completely to o-phosphate during the frozen storage of ''surimi'', therefore, the application of ..gamma..-ray irradiation on ''kamaboko'' was considered not to induce any injurious substances from polyphosphates.

  19. Gravitational Waves versus X and Gamma Ray Emission in a Short Gamma-Ray Burst

    OpenAIRE

    Oliveira, F. G.; Rueda, Jorge A.; Ruffini, Remo

    2012-01-01

    The recent progress in the understanding the physical nature of neutron star equilibrium configurations and the first observational evidence of a genuinely short gamma-ray burst, GRB 090227B, allows to give an estimate of the gravitational waves versus the X and Gamma-ray emission in a short gamma-ray burst.

  20. Gamma-ray sources

    International Nuclear Information System (INIS)

    Hermsen, W.

    1980-01-01

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

  1. High gamma dose response of the electrical properties of polyethylene terephthalate thin films

    International Nuclear Information System (INIS)

    Radwan, R.M.

    2007-01-01

    Electrical properties of polyethylene terephthalate (PET), irradiated with gamma rays, have been investigated. The PET films were irradiated with high gamma dose levels in the range from 100 to 2000 kGy. The changes in the DC (σ DC ) and the ac (σ ac ) conductivities, with the dose, have been performed. The effect of gamma irradiation on the dielectric constant (ε') and loss (ε'') has been determined. Also, the dose dependence of the frequency exponent index (S), the resonance frequency (Fc) and the hopping frequency (ω P ) have been obtained. The obtained results show that increasing gamma dose leads to slight increase in σ DC , σ ac and ε', while no change was observed in ε'' value. Meanwhile, S, Fc and ω P are inversely proportional to the dose. Accordingly, the study suggests the possibility of using PET films in electronic components (capacitors, resistors, etc.), especially that operate at high gamma dose environments for the frequency independent applications

  2. Calculation of Dose Gamma Ray Build up Factor in Some ...

    African Journals Online (AJOL)

    The gamma ray buildup factor was calculated by analyzing the narrow- beam and broad-beam geometry equations using Taylor's formula for isotropic sources and homogeneous materials. The buildup factor was programmed using MATLAB software to operate with any radiation energy (E), atomic number (Z) and the ...

  3. The effect of gamma ray irradiation on PAN-based intermediate modulus carbon fibers

    International Nuclear Information System (INIS)

    Li, Bin; Feng, Yi; Qian, Gang; Zhang, Jingcheng; Zhuang, Zhong; Wang, Xianping

    2013-01-01

    Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were conducted on PAN-based intermediate modulus carbon fibers to investigate the structure and surface hydrophilicity of the carbon fibers before and after gamma irradiation. Two methods were used to determine Young’s modulus of the carbon fibers. The results show that gamma ray irradiation improved the degree of graphitization and introduced compressive stress into carbon fiber surface. Gamma ray also improved the carbon fiber surface hydrophilicity through increasing the value of O/C and enhancing the quantity of oxygen functional groups on carbon fibers. No distinct morphology change was observed after gamma ray irradiation. The Young’s modulus of the fibers increased with increasing irradiation dose

  4. Equipment for x- and gamma ray radiography

    International Nuclear Information System (INIS)

    Abd Nasir Ibrahim; Azali Muhammad; Ab Razak Hamzah; Abd Aziz Mohamed; Mohammad Pauzi Ismail

    2004-01-01

    The following topics related to the equipment for x - and gamma ray radiography are discussed in this chapter. The topics are x-ray source for Industrial Radiography: properties of x-ray, generation of x-ray, mechanism of x-ray production, x-ray equipment, power supply, distribution of x-ray intensity along the tube: gamma ray source for Industrial Radiography: properties of gamma rays, gamma ray sources, gamma ray projectors on cameras, source changing. Care of Radiographic Equipments: Merits and Demerits of x and Gamma Rays

  5. Influence of gamma rays radiation on lignin degradation potency of phanerochaete chrysosporium and ganoderma lucidum

    International Nuclear Information System (INIS)

    Tri Retno DL; Nana Mulyana; Nurhasni; Uswatun Hasanah

    2016-01-01

    This research aims to increase the activity of extracellular enzymes lignolitik fungi phanerochaete chrysosporium and ganoderma lucidum to degrade lignocellulosic waste. Lignocellulosic difficult to degrade because it is composed of lignin, cellulose and hemicellulose. Phanerochaete chrysosporium and ganoderma lucidum group white rot fungi can degrade lignin because it is able to synthesize enzymes lignin peroxidase (LiP). Irradiation low dose gamma rays capable menstimulsi increase extracellular enzyme activity. Fungi phanerochaete chrysosporium and ganoderma lucidum in medium slent exposed to gamma irradiation at doses of 0 (control), 200, 400, 600, 800 and 1000 Gy. In a liquid medium containing Potatoes Dextrose Broth (PDB), mineral salts with the substrate lignin alkali 0 and 5 % w/v, fungi phanerochaete chrysosporium were exposed to a dose of 600 Gy of gamma rays have LiP activity (30 U/mL) by 2.5 times higher compared with controls (12 U/mL). While ganoderma lucidum that are exposed to gamma radiation at a dose of 800 Gy has LiP activity (34 U/mL) was 1.7 times higher than the control (20 U/mL). On a solid substrate fermentation of white teak powder (Gmelina arborea Roxb.) For 12 days at pH 6.4 and water content of 79 % by fungi phanerochaete chrysosporium were exposed to gamma ray dose of 600 Gy has an efficiency of lignin degradation by 42 %, whereas on fungi ganoderma lucidum that are exposed gamma ray dose of 800 Gy has an efficiency of lignin degradation by 21 % with optimal conditions of pH 7. And; water content of 71.3 %. (author)

  6. Using of gamma rays in stimulation and improvement of mushroom spawns plerotus ostreatus

    International Nuclear Information System (INIS)

    Hussein, O.S.; Atia, A.I.

    2009-01-01

    The objective of this work was activation and stimulation of plerotus ostreatus growth and increasing their yields by using of gamma rays, in addition to improvement of mushroom quality and shelf life.Exposing plerotus ostreatus to different doses of gamma rays 2.5, 5, 10 and 15 Gy to determine some of the basic composition of mushroom fruits achieved significant increase in yields and basic composition of resulted mushrooms. Also, increase in carbohydrates content, most of amino acids content and fatty acids content, mainly unsaturated fatty acid i.e., (C 16:1) and (C 18:1,2), which are essential for human nutrition as antioxidant. Whereas, there was a significant decrease in the total phenols content of the resulted fruits, which affected the quality and shelf life of mushroom fruits. All gamma rays doses used increased mushroom yield in fresh and dry wt basis. The recommended dose for spawn irradiation was 10 Gy to increase mushroom yields and its chemical components

  7. Gamma-ray burst polarimeter (GAP)

    International Nuclear Information System (INIS)

    Mihara, Tatehiro; Murakami, Toshio; Yonetoku, Daisuke; Gunji, Shuichi; Kubo, Shin

    2013-01-01

    The gamma-ray burst polarimeter (GAP: GAmma-ray burst Polarimeter), which had been almost handcrafted by scientists, has succeeded in working normally in interplanetary space, and in detecting the polarization of the gamma-ray from a mysterious astronomical object 'gamma-ray burst'. It is the first result of the detectors in the world exclusively aiming at detecting gamma-ray polarization. We mainly describe the hardware of our GAP equipment and show the method of preparing equipment to work in the cosmic space with a tight budget. The mechanical structure, the electronic circuits, the software on the equipment, the data analysis on the earth, and the scientific results gained by the observation just over one year, are presented after explaining the principle of gamma-ray polarization detection. Our design to protect equipment against mechanical shock and cosmic radiation may provide useful information for future preparation of compact satellite. (J.P.N.)

  8. Effect of continuous exposure to very low dose rates of gamma rays on life span and neoplasia in mice

    International Nuclear Information System (INIS)

    Tanaka, I.B. III; Tanaka, Satoshi; Ichinohe, Kazuaki; Matsumoto, Tsuneya; Otsu, Hiroshi; Oghiso, Yoichi; Sato, Fumiaki; Matsushita, Satoru

    2008-01-01

    Late effects of continuous exposure to ionizing radiation are potential hazards to workers in radiation facilities as well as to the general public. In the recent years, low-dose-rate and low-dose effects have become a serious concern. Using a total of 4,000 mice, we studied the late biological effects of chronic exposure to low-dose-rate radiation on life span and neoplasia. Two thousand male and 2000 female 8-week-old specific pathogen free (SPF) B6C3F1 mice were randomly divided into 4 groups, one non-irradiated (control) and three irradiated. The irradiated groups were exposed to 137 Cs gamma rays at dose-rates of 21, 1.1 and 0.05 mGy day -1 for approximately 400 days with total doses equivalent to 8000, 400 and 20 mGy, respectively. All mice were kept under SPF conditions until natural death and pathological examination was performed to determine the cause of death. Statistical analyses showed that the life spans of mice of both sexes irradiated with 21 mGy day -1 (P -1 (P 86.7% of all deaths. Compared to the non-irradiated controls, incidences of lethal neoplasms were significantly increased for myeloid leukaemia and hemangiosarcoma in males, soft tissue neoplasms and malignant granulosa cell tumors in females exposed to 21 mGy day -1 . The number of multiple primary neoplasms per mouse was significantly increased in mice irradiated at 21 mGy day -1 . Our results suggest that life shortening in mice continuously exposed to low dose-rate gamma rays is due to early death from a variety of neoplasms and not from increased incidence of specific lethal neoplasms. (author)

  9. Dose-response calibration curves of {sup 137}Cs gamma rays for dicentric chromosome aberrations in human lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Wol Soon; Oh, Su Jung; Jeong, Soo Kyun; Yang, Kwang Mo [Dept. of Research center, Dong Nam Institute of Radiological and Medical Sciences, Busan (Korea, Republic of); Jeong, Min Ho [Dept. of Microbiology, Dong A University College of Medicine, Busan (Korea, Republic of)

    2012-11-15

    Recently, the increased threat of radiologically industrial accident such as radiation nondestructive inspection or destruction of nuclear accident by natural disaster such as Fukushima accident requires a greater capacity for cytogenetic biodosimetry, which is critical for clinical triage of potentially thousands of radiation-exposed individuals. Dicentric chromosome aberration analysis is the conventional means of assessing radiation exposure. Dose–response calibration curves for {sup 13}'7Cs gamma rays have been established for unstable chromosome aberrations in human peripheral blood lymphocytes in many laboratories of international biodosimetry network. In this study, therefore, we established dose– response calibration curves of our laboratory for {sup 137}Cs gamma raysaccording to the IAEA protocols for conducting the dicentric chromosome assay We established in vitro dose–response calibration curves for dicentric chromosome aberrations in human lymphocytes for{sup 13}'7Cs gamma rays in the 0 to 5 Gy range, using the maximum likelihood linear-quadratic model, Y = c+αD+βD2. The estimated coefficients of the fitted curves were within the 95% confidence intervals (CIs) and the curve fitting of dose–effect relationship data indicated a good fit to the linear-quadratic model. Hence, meaningful dose estimation from unknown sample can be determined accurately by using our laboratory’s calibration curve according to standard protocol.

  10. A shape and mesh adaptive computational methodology for gamma ray dose from volumetric sources

    International Nuclear Information System (INIS)

    Mirza, N.M.; Ali, B.; Mirza, S.M.; Tufail, M.; Ahmad, N.

    1991-01-01

    Indoor external exposure to the population is dominated by gamma rays emitted from the walls and the floor of a room. A shape and mesh size adaptive flux calculational approach has been developed for a typical wall source. Parametric studies of the effect of mesh size on flux calculations have been done. The optimum value of the mesh size is found to depend strongly on distance from the source, permissible limits on uncertainty in flux predictions and on computer Central Processing Unit time. To test the computations, a typical wall source was reduced to a point, a line and an infinite volume source having finite thickness, and the computed flux values were compared with values from corresponding analytical expressions for these sources. Results indicate that the errors under optimum conditions remain less than 6% for the fluxes calculated from this approach when compared with the analytical values for the point and the line source approximations. Also, when the wall is simulated as an infinite volume source having finite thickness, the errors in computed to analytical flux ratios remain large for smaller wall dimensions. However, the errors become less than 10% when the wall dimensions are greater than ten mean free paths for 3 MeV gamma rays. Also, specific dose rates from this methodology remain within the difference of 15% for the values obtained by Monte Carlo method. (author)

  11. Gamma ray astronomy

    International Nuclear Information System (INIS)

    Hillier, R.

    1984-01-01

    The book reviews the development of gamma ray astronomy over the past twenty five years. A large section of the book is devoted to the problems of background radiation and the design of detectors. Gamma rays from the sun, the galactic disc, the galaxy, and extra galactic sources; are also discussed. (U.K.)

  12. Tuning surface properties of graphene oxide quantum dots by gamma-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Shunkai; Liao, Fan, E-mail: fliao@suda.edu.cn; Wang, Tao; Zhu, Lili; Shao, Mingwang, E-mail: mwshao@suda.edu.cn

    2016-07-15

    Gamma-ray irradiation was employed to tune surface properties of graphene oxide quantum dots (GOQDs), such as functional groups and defect density. The GOQDs were first oxidized under γ-ray irradiation with doses ranging from 0 to 200 kGy, and then reduced under larger irradiation doses from 200 to 400 kGy. In other words, both the defect density and the number of surface functional groups increased first and then decreased along with the increasing irradiation dose. This process was confirmed with UV–visible absorption, X-ray photoelectron spectroscopy, Raman spectra and Fourier transform infrared spectra. In order to estimate their π-conjugated content, the GOQDs were served to quench the fluorescence of Rhodamine 6 G. The results showed that there existed a positive relationship between the π-conjugated content and the static quenching coefficient V{sub q}Na, which might have a potential value. - Highlights: • The conjugate extent and hydrophily of GOQDs decreased along with irradiation dose. • Gamma-ray irradiation weakens the quenching effect of GOQDs. • Quenching mechanism is a combination of dynamic and static quenching.

  13. Inhibition of gamma-ray dose-rate effects by D/sup 2/O and inhibitors of poly(ADP-ribose) synthetase in cultured mammalian L5178Y cells

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, A.M.; Tanaka, O.; Matsudaira, H.

    1984-06-01

    Effects of deuterium oxide (D/sub 2/O) and 3-aminobenzamide, an inhibitor of poly(ADP-ribose) synthetase, on cell proliferation and survival were studied in cultured mammalian L5178Y cells under growing conditions and after acute and low-dose-rate irradiation at about 0.1 to 0.4 Gy/hr of ..gamma.. rays. Growth of irradiated and unirradiated cells was inhibited by 45% D/sub 2/O but not by 3-aminobenzamide at 10mM, except for treatments longer than 30 hr. The presence of these agents either alone or in combination during irradiation at low dose rates suppressed almost totally the decrease in cell killing due to the decrease in dose rate. Among other inhibitors tested, theobromine and theophylline were found to be effective in eliminating the dose-rate effects of ..gamma.. rays. Possible mechanisms underlying the inhibition are discussed.

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

    Science.gov (United States)

    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.

  15. A gamma-ray discriminating neutron scintillator

    International Nuclear Information System (INIS)

    Eschbach, P.A.; Miller, S.D.; Cole, M.C.

    1994-01-01

    A neutron scintillator has been developed at Pacific Northwest Laboratory which responds directly to as little as 10 mrem/hour dose equivalent rate fast neutron fields. The scintillator is composed of CaF 2 :Eu or of NaI grains within a silicone rubber or polystyrene matrix, respectively. Neutrons colliding with the plastic matrix provide knockon protons, which in turn deposit energy within the grains of phosphor to produce pulses of light. Neutron interactions are discriminated from gamma-ray events on the basis of pulse height. Unlike NE-213 liquid scintillators, this solid scintillator requires no pulseshape discrimination and therefore requires less hardware. Neutron events are anywhere from two to three times larger than the gamma-ray exposures are compared to 0.7 MeV gamma-ray exposures. The CaF 2 :Eu/silicone rubber scintillator is nearly optically transparent, and can be made into a very sizable detector (4 cm x 1.5 cm) without degrading pulse height. This CaF 2 :Eu scintillator has been observed to have an absolute efficiency of 0.1% when exposed to 5-MeV accelerator-generated neutrons (where the absolute efficiency is the ratio of observed neutron events divided by the number of fast neutrons striking the detector)

  16. Mapping the outdoor gamma dose rate in Indonesia

    International Nuclear Information System (INIS)

    Iskandar, Dadong; Syarbaini, Sutarman; Bunawas, Kusdiana

    2008-01-01

    Full text: Indonesia is the largest archipelago in the world, comprising five main islands - Java, Sumatra, Sulawesi, Kalimantan and Papua - as well as 30 archipelagoes totaling 17,508 islands with about 6000 of those inhabited. Mapping the outdoor gamma dose rate in Indonesia is a research project conducted by National Nuclear Energy Agency since 2005 aiming to produce a baseline data map as an overview for planning purposes. In these three years 4 main islands has been measured. The grid system has been used in the research. In Sumatra Island the grid is 50 x 50 km 2 , while in Java 40 x 40 km 2 , in Kalimantan 60 x 60 km 2 , and in Sulawesi 40 x 40 km 2 . The gamma dose rates have been measured by Mini Gamma Ray Spectrometer Model GR-130 made by Exploranium-Canada. Figure 1 shows the map of outdoor gamma dose rate in Indonesia. Range of dose rate are in Sumatra from 22,96 ± 0,46 n Sv/h to 186,08 ± 3,72 n Sv/h, in Java 11,32 ± 0,72 n Sv/h to 127,54 ± 6,14 n Sv/h, in Kalimantan 10.72 ± 8.32 n Sv/h to 349,48 ± 57,21 n Sv/h, and in Sulawesi 17.7 ± 11,5 n Sv/h to 467 ± 102 n Sv/h. The arithmetic and geometric mean of dose rate in Indonesia are 68 n Sv/h and 53 n Sv/h, respectively. In general, outdoor gamma dose rate in Indonesia is in a normal range. There are some regions have anomaly of gamma dose rate, for examples at North Sumatra 186.08 ± 3,72 n Sv/h (N 2.12727, E 99.80909), at West Kalimantan 349,48 ± 57,21 n Sv/h (S 1.39507, E 110.57584), at West Sulawesi 487 ± 103 n Sv/h (S 2.95781, E 118.86995), etc. These data is very useful as a radiation baseline in Indonesia. (author)

  17. Degradation and annealing studies on gamma rays irradiated COTS PPD CISs at different dose rates

    International Nuclear Information System (INIS)

    Wang, Zujun; Ma, Yingwu; Liu, Jing; Xue, Yuan; He, Baoping; Yao, Zhibin; Huang, Shaoyan; Liu, Minbo; Sheng, Jiangkun

    2016-01-01

    The degradation and annealing studies on Colbalt-60 gamma-rays irradiated commercial-off-the-shelf (COTS) pinned photodiode (PPD) CMOS image sensors (CISs) at the various dose rates are presented. The irradiation experiments of COTS PPD CISs are carried out at 0.3, 3.0 and 30.0 rad(Si)/s. The COTS PPD CISs are manufactured using a standard 0.18-μm CMOS technology with four-transistor pixel PPD architecture. The behavior of the tested CISs shows a remarkable degradation after irradiation and differs in the dose rates. The dark current, dark signal non-uniformity (DSNU), random noise, saturation output, signal to noise ratio (SNR), and dynamic range (DR) versus the total ionizing dose (TID) at the various dose rates are investigated. The tendency of dark current, DSNU, and random noise increase and saturation output, SNR, and DR to decrease at 3.0 rad(Si)/s are far greater than those at 0.3 and 30.0 rad(Si)/s. The damage mechanisms caused by TID irradiation at the various dose rates are also analyzed. The annealing tests are carried out at room temperature with unbiased conditions after irradiation.

  18. Degradation and annealing studies on gamma rays irradiated COTS PPD CISs at different dose rates

    Science.gov (United States)

    Wang, Zujun; Ma, Yingwu; Liu, Jing; Xue, Yuan; He, Baoping; Yao, Zhibin; Huang, Shaoyan; Liu, Minbo; Sheng, Jiangkun

    2016-06-01

    The degradation and annealing studies on Colbalt-60 gamma-rays irradiated commercial-off-the-shelf (COTS) pinned photodiode (PPD) CMOS image sensors (CISs) at the various dose rates are presented. The irradiation experiments of COTS PPD CISs are carried out at 0.3, 3.0 and 30.0 rad(Si)/s. The COTS PPD CISs are manufactured using a standard 0.18-μm CMOS technology with four-transistor pixel PPD architecture. The behavior of the tested CISs shows a remarkable degradation after irradiation and differs in the dose rates. The dark current, dark signal non-uniformity (DSNU), random noise, saturation output, signal to noise ratio (SNR), and dynamic range (DR) versus the total ionizing dose (TID) at the various dose rates are investigated. The tendency of dark current, DSNU, and random noise increase and saturation output, SNR, and DR to decrease at 3.0 rad(Si)/s are far greater than those at 0.3 and 30.0 rad(Si)/s. The damage mechanisms caused by TID irradiation at the various dose rates are also analyzed. The annealing tests are carried out at room temperature with unbiased conditions after irradiation.

  19. Study of the contribution of X-ray and gamma photons to the measured exposure dose

    International Nuclear Information System (INIS)

    Andriampanarivo, H.L.H.

    2000-01-01

    The aim of this work was to study the contribution of X-rays and gamma radiation to the measured dose in the city of Antananarivo. The annual indoor absorbed dose was studied as well. Measurements were carried out in twelve sites, namely public schools and churches. The mean dose rate lies between (0.34±0.03)μSv/h and (0.38±0.04)μSv/h for most of the sites. Two of them showed values between (0.40±0.04)μSv/h and (0.30±0.03)μSv/h. Mean indoor dose rate is of (0.36±0.04)μSv/h and the annual absorbed dose is (3.16±0.32)mSv/person. Indoor measurements showed mean integral values ranging from (277.22±0,22)cps to (733.66±0,37)cps. The lowest mean count rate is (277.22±0,22)cps, measured in the AMARO site, whereas the highest are (733,66±0,37)cps, (697,81±0,36)cps and (689,32±0,36)cps measured in ALO0 , AKELY, and MASINA respectively. [fr

  20. Space instrumentation for gamma-ray astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Teegarden, B.J

    1999-02-11

    The decade of the 1990s has witnessed a renaissance in the field of gamma-ray astronomy. The seminal event was the launch of the Compton Gamma-Ray Observatory (CGRO) in April 1991. There have been a flood of major discoveries from CGRO including breakthroughs in gamma-ray bursts, annihilation radiation, and blazars. The Italian SAX satellite was launched in April 1996. Although not primarily a gamma-ray mission, it has added a new dimension to our understanding of gamma-ray bursts. Along with these new discoveries a firm groundwork has been laid for missions and new technology development that should maintain a healthy and vigorous field throughout most of the next decade. These include the ESA INTEGRAL mission (INTErnational Gamma-Ray Astrophysics Laboratory, to be launched in mid-2001) and the NASA GLAST mission (Gamma-Ray Large Area Space Telescope) with a likely launch in the middle of the next decade. These two missions will extend the observational capabilities well beyond those of CGRO. New technologies (to gamma-ray astronomy), such as cooled germanium detectors, silicon strip detectors, and CdTe detectors are planned for these new missions. Additional promising new technologies such as CdZnTe strip detectors, scintillator fibers, and a gamma-ray lens for future gamma-ray astronomy missions are under development in laboratories around the world.

  1. Space instrumentation for gamma-ray astronomy

    International Nuclear Information System (INIS)

    Teegarden, B.J.

    1999-01-01

    The decade of the 1990s has witnessed a renaissance in the field of gamma-ray astronomy. The seminal event was the launch of the Compton Gamma-Ray Observatory (CGRO) in April 1991. There have been a flood of major discoveries from CGRO including breakthroughs in gamma-ray bursts, annihilation radiation, and blazars. The Italian SAX satellite was launched in April 1996. Although not primarily a gamma-ray mission, it has added a new dimension to our understanding of gamma-ray bursts. Along with these new discoveries a firm groundwork has been laid for missions and new technology development that should maintain a healthy and vigorous field throughout most of the next decade. These include the ESA INTEGRAL mission (INTErnational Gamma-Ray Astrophysics Laboratory, to be launched in mid-2001) and the NASA GLAST mission (Gamma-Ray Large Area Space Telescope) with a likely launch in the middle of the next decade. These two missions will extend the observational capabilities well beyond those of CGRO. New technologies (to gamma-ray astronomy), such as cooled germanium detectors, silicon strip detectors, and CdTe detectors are planned for these new missions. Additional promising new technologies such as CdZnTe strip detectors, scintillator fibers, and a gamma-ray lens for future gamma-ray astronomy missions are under development in laboratories around the world

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

    Directory of Open Access Journals (Sweden)

    Milić Pejović

    2013-01-01

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

  3. Research of pulse gamma ray radiation effect on microcontroller system

    International Nuclear Information System (INIS)

    Yang Shanchao; Ma Qiang; Jin Xiaoming; Li Ruibin; Lin Dongsheng; Chen Wei; Liu Yan

    2012-01-01

    An experimental result of power chip LM7805 and microcontroller EE80C196KC20 based on the EE80C196KC20 testing system was presented. The pulse gamma ray radiation effect was investigated using 'Qiangguang-Ⅰ' accelerator. Latchup threshold of the microcontroller was obtained, and the relationship of supply current and I/O output with the transient dose rate was observed. The result shows that the restrainability of power chip on pulse gamma ray radiation induces microcontroller latchup effect. (authors)

  4. Experimental study on x-rays dose enhancement effects for floating gate ROMs

    CERN Document Server

    Guo Hong Xia; Chen Yu Sheng; Han Fu Bin; He Chao Hui; Zhao Hui

    2002-01-01

    Experimental results of x-ray dose enhancement effects are given for floating gate read-only memory (ROMs) irradiated in the Beijing Synchrotron Radiation Facility. The wrong byte numbers vs. total irradiation dose have been tested and the equivalent relation of total dose damage is provided compared the response of devices irradiated with sup 6 sup 0 Co gamma-ray source. The x-ray dose enhancement factors for floating gate ROMs are obtained firstly in China. These results can be an effective evaluation data for x-rays radiation hardening technology

  5. GRAYSKY-A new gamma-ray skyshine code

    International Nuclear Information System (INIS)

    Witts, D.J.; Twardowski, T.; Watmough, M.H.

    1993-01-01

    This paper describes a new prototype gamma-ray skyshine code GRAYSKY (Gamma-RAY SKYshine) that has been developed at BNFL, as part of an industrially based master of science course, to overcome the problems encountered with SKYSHINEII and RANKERN. GRAYSKY is a point kernel code based on the use of a skyshine response function. The scattering within source or shield materials is accounted for by the use of buildup factors. This is an approximate method of solution but one that has been shown to produce results that are acceptable for dose rate predictions on operating plants. The novel features of GRAYSKY are as follows: 1. The code is fully integrated with a semianalytical point kernel shielding code, currently under development at BNFL, which offers powerful solid-body modeling capabilities. 2. The geometry modeling also allows the skyshine response function to be used in a manner that accounts for the shielding of air-scattered radiation. 3. Skyshine buildup factors calculated using the skyshine response function have been used as well as dose buildup factors

  6. Prompt gamma-ray imaging for small animals

    Science.gov (United States)

    Xu, Libai

    codes GEANT4 or MCNP5, to predict results and investigate the feasibility of this new imaging idea. Benchmark experiments have been conducted to test the capability of the code to simulate prompt gamma rays, which are produced by following the nuclear structures of each irradiated isotope, and coincidence counting techniques, which are considered the most important improvement in neutron-related gamma-ray detection applications to reduce gamma background and improve system signal-to-noise ratios. With coincidence prompt gamma rays available, two major imaging techniques, electronic collimations and mechanic collimations, are implemented in the simulation to illustrate the feasibility of imaging elemental distribution by this new technique. The expectation maximization algorithm is employed in electronic collimation to reconstruct images. The common SPECT imaging algorithms are used in mechanical collimation to get an image. Several critical topics concerning practical applications have already been discussed, such as the radiation dose to the mouse and the detection efficiency of high-energy gamma rays. The funding of this work is provided by the Center for Engineering Application of Radioisotopes (CEAR) at North Carolina State University (NCSU) and Nuclear Engineering Education Research.

  7. Gamma ray induced chlorophyll and morphological mutants in grasspea

    International Nuclear Information System (INIS)

    Das, P.K.; Kundagrami, S.

    2000-01-01

    Higher dose of gamma ray treatment such as 30 kR promoted larger chlorophyll as well as morphological mutation frequency and spectrum. In both M 1 and M 2 generation marginata significantly out numbered other types of chlorophyll mutations. On the other hand, along morphological mutations stunted growth types were recovered more frequently. Both the genotypes Nirmal and P-24 differed greatly for their mutagenic specificity. In both M 1 and M 2 generation Nirmal recorded higher chlorophyll and morphological mutation frequency and spectrum indicating differential genotype response to different dosages of gamma ray treatment. (author)

  8. Gamma ray astronomy

    International Nuclear Information System (INIS)

    Broomhead, Laurent.

    1980-01-01

    The nuclear gamma astronomy is presented, in particular the Gamma Ray Observatory, an enormous eight tonnes machine fitted with gamma telescopes, scheduled for launching around 1985. It is thereby hoped to study the natural nuclear reactions which occur when stars explode [fr

  9. Natural gamma-ray emitters in clays used for therapeutic purposes

    International Nuclear Information System (INIS)

    Maduar, Marcelo F.; Silva, Paulo S.C. da; Ponciano, Ricardo

    2013-01-01

    The use of minerals for therapeutic purposes is an ancient practice, especially clay minerals topically employed in the therapy of skin disorders and rheumatic processes. In Brazil, an example of such application is the use of a clay-based mineral extracted from a deposit in Peruibe, a resort town in the country southeast. Such mineral has been used both in raw form, after a washing process or as an active component of cosmetics. Currently, a comprehensive characterization of samples from this deposit is underway. As a part of this work, this paper presents preliminary results of the determination of natural radionuclides in samples of this clay and its derived preparations, in order to evaluate the radiological implications of such practice. The raw samples, after preparation, were analyzed by gamma-ray spectrometry. Self-attenuation corrections for the 210 Pb gamma radiation were applied. The radionuclide concentrations in dried samples varied in the ranges: for 226 Ra, 15.3 ± 0.5 to 18.4 ± 0.7 Bq-kg -1 ; for 228 Ra, 31.2 ± 0.5 to 37.8 ± 0.9 Bq-kg -1 ; for 210 Pb, 18 ± 5 to 32 ± 6 Bq-kg -1 ; for 40 K, 373 ± 14 to 454 ± 20 Bq-kg -1 . The concentrations obtained are consistent with previously ones reported for clays. For the cosmetics, none of the target radionuclides were detected above the minimum detectable activities of the counting system, which are 2.5, 2.0, 10 and 20 Bq-kg -1 respectively for 226 Ra, 228 Ra, 210 Pb, and 40 K. An estimation of the effective dose on the skin due to the clay application by a modelling tool, with conservative parameters, led to an effective dose of 0.8 microsievert, indicating that the studied practice causes no significant radiation dose increment to the public. (author)

  10. Radiation hardness of GaAs sensors against gamma-rays, neutrons and electrons

    Energy Technology Data Exchange (ETDEWEB)

    Šagátová, Andrea, E-mail: andrea.sagatova@stuba.sk [Institute of Nuclear and Physical Engineering, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovičova 3, 812 19 Bratislava (Slovakia); University Centre of Electron Accelerators, Slovak Medical University, Ku kyselke 497, 911 06 Trenčín (Slovakia); Zaťko, Bohumír; Dubecký, František [Institute of Electrical Engineering, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04 Bratislava (Slovakia); Ly Anh, Tu [Faculty of Applied Science, University of Technology VNU HCM, 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City (Viet Nam); Nečas, Vladimír; Sedlačková, Katarína; Pavlovič, Márius [Institute of Nuclear and Physical Engineering, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovičova 3, 812 19 Bratislava (Slovakia); Fülöp, Marko [University Centre of Electron Accelerators, Slovak Medical University, Ku kyselke 497, 911 06 Trenčín (Slovakia)

    2017-02-15

    Highlights: • Radiation hardness of SI GaAs detectors against gamma-rays, neutrons and electrons was compared. • Good agreement was achieved between the experimental results and displacement damage factor of different types of radiation. • CCE and FWHM first slightly improved (by 1–8%) and just then degraded with the cumulative dose. • An increase of detection efficiency with cumulative dose was observed. - Abstract: Radiation hardness of semi-insulating GaAs detectors against {sup 60}Co gamma-rays, fast neutrons and 5 MeV electrons was compared. Slight improvements in charge collection efficiency (CCE) and energy resolution in FWHM (Full Width at Half Maximum) were observed at low doses with all kinds of radiation followed by their degradation. The effect occurred at a dose of about 10 Gy of neutrons (CCE improved by 1%, FWHM by 5% on average), at 1 kGy of electrons (FWHM decreased by 3% on average) and at 10 kGy of gamma-rays (CCE raised by 5% and FWHM dropped by 8% on average), which is in agreement with the relative displacement damage of the used types of radiation. Gamma-rays of MeV energies are 1000-times less damaging than similar neutrons and electrons about 10-times more damaging than photons. On irradiating the detectors with neutrons and electrons, we observed a global increase in their detection efficiency, which was caused probably by enlargement of the active detector area as a consequence of created radiation defects in the base material. Detectors were still functional after a dose of 1140 kGy of ∼1 MeV photons, 104 kGy of 5 MeV electrons but only up to 0.576 kGy of fast (∼2 to 30 MeV) neutrons.

  11. Development of the 60Co gamma-ray standard field for therapy-level dosimeter calibration in terms of absorbed dose to water (ND,W)

    International Nuclear Information System (INIS)

    Fukumura, Akifumi; Mizuno, Hideyuki; Fukahori, Mai; Sakata, Suoh

    2013-01-01

    A primary standard for the absorbed dose rate to water in a 60 Co gamma-ray field was established at National Metrology Institute of Japan (NMIJ) in fiscal year 2011. Then, a 60 Co gamma-ray standard field for therapy-level dosimeter calibration in terms of absorbed dose to water was developed at National Institute of Radiological Sciences (NIRS) as a secondary standard dosimetry laboratory (SSDL). The results of an International Atomic Energy Agency (IAEA)/World Health Organization (WHO) TLD SSDL audit demonstrated that there was good agreement between NIRS stated absorbed dose to water and IAEA measurements. The IAEA guide based on the International Organization for Standardization (ISO) standard was used to estimate the relative expanded uncertainty of the calibration factor for a therapy-level Farmer type ionization chamber in terms of absorbed dose to water (N D,W ) with the new field. The uncertainty of N D,W was estimated to be 1.1% (k=2), which corresponds to approximately one third of the value determined in the existing air kerma field. The dissemination of traceability of the calibration factor determined in the new field is expected to diminish the uncertainty of dose delivered to patients significantly. (author)

  12. SU-E-T-94: An Advanced Rotating Gamma Ray System for Stereotactic Radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Ma, C; Chibani, O; Li, J; Chen, L [Fox Chase Cancer Center, Philadelphia, PA (United States); Mora, G [Universidade de Lisboa, Codex, Lisboa (Portugal)

    2015-06-15

    Purpose: Co-60 beams have unique dosimetric properties that are ideally suited for cranial treatments. Co-60 sources with cone-shaped collimators provide conformal dose distributions allowing for ablative treatments with rapid dose falloff to spare nearby critical structures. This work investigates a novel, image-guided, rotational Gamma ray system that provides both superior dose conformity/gradient and accurate stereotaxy for stereotactic radiosurgery (SRS). Methods: The SupeRay system (Cyber Medical Corp., China) consists of a rotating source chamber containing 30 gamma sources focusing at the isocenter with 4 collimators measuring 3, 4, 8 and 16mm in diameter. A novel switch design enables the 30 Gamma sources to be turned off at any arbitrarily selected 60° interval in order to avoid critical structures. The 3D treatment couch provides automatic treatment positioning between individual shots and the kV imaging system provides orthogonal images with a spatial resolution of 0.24mm to facilitate target localization. Monte Carlo simulations were used to compute dose distributions and compare with measurements and other Gamma ray SRS systems. Results: Monte Carlo results confirmed the SupeRay design parameters including output factors and 3D dose distributions. Its beam penumbra/dose gradient is similar to or slightly better than that of the Elekta Gamma Knife. The penumbra in the (x,y,z) direction was (7.38mm,7.38mm,3.86mm) for the 16mm collimator, (4.83mm,4.83mm,3.12mm) for the 8mm collimator, and (3.03mm,3.03mm,2.38mm) for the 4mm collimator, respectively, on the SupeRay system while it was (9.5mm,10.0mm,2.9mm), (4.3mm,4.3mm,2.9mm) and (3.2mm,3.2mm,1.9mm) for the same collimator sizes, respectively, on the Perfexion system. The kV imaging system together with a non-invasive relocatable frame provides accurate target localization (<0.5mm) for cases requiring multiple treatment fractions. Conclusion: Because of the unique dosimetric properties of Co-60 sources

  13. Analysis of gamma dose for 4,8 gU/cm3 density silicide core at the RSG-GAS reactor using MCNP code

    International Nuclear Information System (INIS)

    Ardani

    2011-01-01

    Radiation safety analysis should be done following of substitution of fuel density of 2.96 gU/cc to density of 4,8 gU/cc silicide fuels for the RSG-GAS reactor. MCNP-5 code has been used to perform gamma dose calculation of the RSG-GAS reactor. Gamma radiation source at reactor consists of capture gamma rays, prompt fission gamma rays, and gamma rays of decay of fission and activation products. The strength of the prompt fission gamma rays is obtained by gamma releases of fission process of U-235 and reactor power of 30 MWt., during 46,6 days operation. Radiation dose is calculated at the experimental hall by detection point at the surface of outer of biological shielding and the operation hall by detection point at the top of the pool. The calculation is conducted at reactor on the normal operation and on the worst postulated accident causing the water level at the pool decreases. Calculation result shows that the biggest source strength of gamma rays come from the decay process. The highest calculated dose at the experiment hall is 4,07x10 -3 μSv/h, far from the maximum external dose permitted 25 μSv/h. The highest calculated dose at the operation hall is 19.98 μSv/h. Even though the calculated dose is still acceptable but this is close to the maximum permitted dose for worker. It concluded that loading of 4,8 gU/cc silicide fuel for the RSG-GAS still safe. (author)

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

    Science.gov (United States)

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

    2016-12-01

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

  15. Cosmic gamma-ray burst

    International Nuclear Information System (INIS)

    Yamagami, Takamasa

    1985-01-01

    Ballon experiments for searching gamma-ray burst were carried out by employing rotating-cross modulation collimators. From a very long observation of total 315 hours during 1975 to 1979, three gamma-ray intensity anomalies were observed which were speculated as a gamma-ray burst. As for the first gamma-ray intensity anomaly observed in 1975, the burst source could be located precisely but the source, heavenly body, could not be specified. Gamma-ray burst source estimation was made by analyzing distribution of burst source in the celestial sphere, burst size distribution, and burst peak. Using the above-mentioned data together with previously published ones, apparent inconsistency was found between the observed results and the adopted theory that the source was in the Galaxy, and this inconsistency was found due to the different time profiles of the burst observed with instruments of different efficiency. It was concluded by these analysis results that employment of logN - logP (relation between burst frequency and burst count) was better than that of logN - logS (burst size) in the examination of gamma-ray burst because the former was less uncertain than the latter. Analyzing the author's observed gamma-ray burst data and the related published data, it was clarified that the burst distribution was almost P -312 for the burst peak value larger than 10 -6 erg/cm 2 .sec. The author could indicate that the calculated celestial distribution of burst source was consistent with the observed results by the derivation using the logN - logP relationship and that the burst larger than 10 -6 erg/cm 2 .sec happens about one thousand times a year, about ten times of the previous value. (Takagi, S.)

  16. Comparative study on disinfection potency of spore forming bacteria by electron-beam irradiation and gamma-ray irradiation

    International Nuclear Information System (INIS)

    Takizawa, Hironobu; Suzuki, Satoru; Suzuki, Tetsuya; Takama, Kozo; Hayashi, Toru; Yasumoto, Kyoden.

    1990-01-01

    Along with gamma-ray irradiation, electron-beam irradiation (EB) is a method to disinfect microorganisms which cause food decomposition and food-poisoning. The present study was undertaken to compare sterilization efficacy of EB and gamma-ray irradiation on bacterial spores and vegetative cells under various conditions. Spores of Bacillus pumilus, a marker strain for irradiation study, and Bacillus stearothermophilus known as a thermophilic bacteria were irradiated by electron-beam and gamma-ray separately at irradiation dose of 0 to 10 kGy on combination of wet/dry and aerobic/anaerobic conditions. Sterilization effect of irradiation on spores was evaluated by colony counting on agar plates. Results showed that both EB and gamma-ray irradiation gave sufficient sterilization effect on spores, and the sterilization effect increased exponentially with irradiation dose. The sterilization effect of gamma-ray irradiation was higher than that of EB in all cases. Higher disinfection effect was observed under aerobic condition. The present study suggests that oxygen supply in EB is more important than gamma-ray irradiation. No results suggesting that chlorine ion at 0.1 ppm (as available chlorine concentration) enhanced the sterilization efficacy of either EB or gamma-ray irradiation was obtained under any conditions examined. (author)

  17. Comparative study on disinfection potency of spore forming bacteria by electron-beam irradiation and gamma-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Takizawa, Hironobu; Suzuki, Satoru; Suzuki, Tetsuya; Takama, Kozo [Hokkaido Univ., Hakodate (Japan). Faculty of Fisheries; Hayashi, Toru; Yasumoto, Kyoden

    1990-10-01

    Along with gamma-ray irradiation, electron-beam irradiation (EB) is a method to disinfect microorganisms which cause food decomposition and food-poisoning. The present study was undertaken to compare sterilization efficacy of EB and gamma-ray irradiation on bacterial spores and vegetative cells under various conditions. Spores of Bacillus pumilus, a marker strain for irradiation study, and Bacillus stearothermophilus known as a thermophilic bacteria were irradiated by electron-beam and gamma-ray separately at irradiation dose of 0 to 10 kGy on combination of wet/dry and aerobic/anaerobic conditions. Sterilization effect of irradiation on spores was evaluated by colony counting on agar plates. Results showed that both EB and gamma-ray irradiation gave sufficient sterilization effect on spores, and the sterilization effect increased exponentially with irradiation dose. The sterilization effect of gamma-ray irradiation was higher than that of EB in all cases. Higher disinfection effect was observed under aerobic condition. The present study suggests that oxygen supply in EB is more important than gamma-ray irradiation. No results suggesting that chlorine ion at 0.1 ppm (as available chlorine concentration) enhanced the sterilization efficacy of either EB or gamma-ray irradiation was obtained under any conditions examined. (author).

  18. Gamma-Ray Astronomy Technology Needs

    Science.gov (United States)

    Gehrels, N.; Cannizzo, J. K.

    2012-01-01

    In recent decades gamma-ray observations have become a valuable tool for studying the universe. Progress made in diverse 8re1lS such as gamma-ray bursts (GRBs), nucleosynthesis, and active galactic nuclei (AGNs) has complimented and enriched our astrophysical understanding in many ways. We present an overview of current and future planned space y-ray missions and discussion technology needs for- the next generation of space gamma-ray instruments.

  19. GRAP, Gamma-Ray Level-Scheme Assignment

    International Nuclear Information System (INIS)

    Franklyn, C.B.

    2002-01-01

    1 - Description of program or function: An interactive program for allocating gamma-rays to an energy level scheme. Procedure allows for searching for new candidate levels of the form: 1) L1 + G(A) + G(B) = L2; 2) G(A) + G(B) = G(C); 3) G(A) + G(B) = C (C is a user defined number); 4) L1 + G(A) + G(B) + G(C) = L2. Procedure indicates intensity balance of feed and decay of each energy level. Provides for optimization of a level energy (and associated error). Overall procedure allows for pre-defining of certain gamma-rays as belonging to particular regions of the level scheme, for example, high energy transition levels, or due to beta- decay. 2 - Method of solution: Search for cases in which the energy difference between two energy levels is equal to a gamma-ray energy within user-defined limits. 3 - Restrictions on the complexity of the problem: Maximum number of gamma-rays: 999; Maximum gamma ray energy: 32000 units; Minimum gamma ray energy: 10 units; Maximum gamma-ray intensity: 32000 units; Minimum gamma-ray intensity: 0.001 units; Maximum number of levels: 255; Maximum level energy: 32000 units; Minimum level energy: 10 units; Maximum error on energy, intensity: 32 units; Minimum error on energy, intensity: 0.001 units; Maximum number of combinations: 6400 (ca); Maximum number of gamma-ray types : 127

  20. Optical fiber sensor for low dose gamma irradiation monitoring

    Science.gov (United States)

    de Andrés, Ana I.; Esteban, Ã.`scar; Embid, Miguel

    2016-05-01

    An optical fiber gamma ray detector is presented in this work. It is based on a Terbium doped Gadolinium Oxysulfide (Gd2O2S:Tb) scintillating powder which cover a chemically etched polymer fiber tip. This etching improves the fluorescence gathering by the optical fiber. The final diameter has been selected to fulfill the trade-off between light gathering and mechanical strength. Powder has been encapsulated inside a microtube where the fiber tip is immersed. The sensor has been irradiated with different air Kerma doses up to 2 Gy/h with a 137Cs source, and the spectral distribution of the fluorescence intensity has been recorded in a commercial grade CCD spectrometer. The obtained signal-to-noise ratio is good enough even for low doses, which has allowed to reduce the integration time in the spectrometer. The presented results show the feasibility for using low cost equipment to detect/measure ionizing radiation as gamma rays are.

  1. Effects of low doses of gamma rays on yield, yield components, and other characters of two maize varieties

    International Nuclear Information System (INIS)

    Yousif, Z. B.; Jabbo, N. F.; Khalaf, M. Z.; Majid, A. H.; Ali, H. J.

    1994-01-01

    The study was conducted during the fall of 1991 and 1992 at Al-Latyfia Experimental Station to determine the effect of low doses of gamma rays on yield, yield components, and other characters of two maize varieties. Five doses were used in addition to control. A factorial experiment with randomized complete block design in three replications was used in the study. Results revealed that there was significant difference between varieties in plant and ear height in 1992. However, differences between varieties were also significantly affected by most yield component characters. Low doses significantly affected plant height, weight of 500 kernels in 1991, and kernel row number in 1992. Grain yield was affected significantly in 1991 and 1992 by low doses. Results showed that 2.0 krad was the most useful low dose to increase grain yield, whereas there was no significant effect between varieties in grain yield. 7 refs., 6 tabs

  2. Observation of solar gamma-ray by Hinotori

    International Nuclear Information System (INIS)

    Yoshimori, Masato; Okudaira, Kiyoaki; Hirashima, Yo; Kondo, Ichiro.

    1982-01-01

    The solar gamma-ray emitted by solar flare was observed. The gamma-ray is the electromagnetic radiation with the energy more than 300 keV. The line gamma-ray intensity and the time profile were observed. The gamma-ray detector CsI (Tl) was loaded on Hinotori, and the observed gamma-ray was analyzed by a multi-channel analyzer. The observed line gamma-ray was the radiation from Fe-56 and Ne-20. The line gamma-ray from C-12 and O-16 was also seen. These gamma-ray is the direct evidence of the nuclear reaction on the sun. The observed spectrum suggested the existence of the lines from Mg-24 and Si-28. The intensity of the 2.22 MeV gamma-line was small. This fact showed that the origin of this line was different from other nuclear gamma-ray. Two kinds of hard X-ray bursts were detected. The one was impulsive burst, and the other was gradual burst. There was no time difference between the hard X-ray and the gamma-ray of the impulsive burst. The impulsive burst may be explained by the beam model. The delay of time profile in the high energy gamma-ray of the gradual burst was observed. This means that the time when accelerated electrons cause bremsstrahlung depends on the electron energy. The long trapping of electrons at the top of magnetic loop is suggested. (Kato, T.)

  3. An Assessment of the Effects of Different Dose Levels of Gamma Rays on HPRT Gene of T-Cells from Human Peripheral Blood

    International Nuclear Information System (INIS)

    Bahreyni, M. T.; Rezaee, M.

    2004-01-01

    Ionizing radiation has been shown to produce a broad range of genetic aberrations in human and other species. Most of the genetic aberrations are deletions. To study genetic alterations, an assessment of somatic ell gene mutations induced by ionizing radiation is proper method. In this study, the intragenic and total gene deletions of 18 HPRT-mutants derived from T-lymphocytes and induced by gamma rays were analyzed. PCR amplification of individual HPRT exons and multiplex PCR. HPRT-mutants were isolated by treatment of irradiated samples with 6-thioguanine. MPCR and PCR of individual exons of HPRT demonstrated that the intragenic and total gene deletions were not significantly different. The samples including more than one deletion had non-random significantly higher frequency. Mapping of all intragenic deleltion exhibited a nonrandom distribution. Middle part of HPRT gene was more sensitive to gamma rays. The sensitivity was increased with radiation dose. This study showed that the size of deletions are dose dependent. Our results suggest that alterations in T- lymphocytes mutant genes, induced deletions, size of deletions and distribution of DNA breakpoints appeared to be dependent on low LET radiation dose. (Author) 11 refs

  4. Adaptive Response to ionizing Radiation Induced by Low Doses of Gamma Rays in Human Lymphoblastoid Cell Lines

    International Nuclear Information System (INIS)

    Seong, Jin Sil; Suh, Chang Ok; Kim, Gwi Eon

    1994-01-01

    When cells are exposed to low doses of a mutagenic or clastogenic agents, they often become less sensitive to the effects of a higher does administered subsequently. Such adaptive responses were first described in Escherichia coli and mammalian cells to low doses of an alkylating agent. Since most of the studies have been carried out with human lymphocytes, it is urgently necessary to study this effect in different cellular systems. Its relation with inherent cellular radiosensitivity and underlying mechanism also remain to be answered. In this study, adaptive response by 1 cGy of gamma rays was investigated in three human lymphoblastoid cell lines which were derived from ataxia telangiectasia homozygote, ataxia telangiectasia heterozygote, and normal individual. Experiments were carried out by delivering 1 cGy followed by 50 cGy of gamma radiation and chromatid breaks were scored as an endpoint. The results indicate that prior exposure to 1 cGy of gamma rays reduces the number of chromatid breaks induced by subsequent higher does (50 cGy). The expression of this adaptive response was similar among three cell lines despite of their different radiosensitivity. When 3-aminobenzamide, an inhibitor of poly (ADP-ribose) polymerase, was added after 50 cGy, adaptive responses were abolished in all the tested cell lines. Therefore it is suggested that the adaptive response can be observed in human lymphoblastoid cell lines. Which was first documented through this study. The expression of adaptive response was similar among the cell lines regardless of their radiosensitivity. The elimination of the adaptive response by 3-aminobenzamide is consistent with the proposal that this adaptive response is the result of the induction of a certain chromosomal repair mechanism

  5. Relativistic motion in gamma-ray bursts

    International Nuclear Information System (INIS)

    Krolik, J.H.; Pier, E.A.

    1991-01-01

    Three fundamental problems affect models of gamma-ray bursts, i.e., the energy source, the ability of high-energy photons to escape the radiation region, and the comparative weakness of X-ray emission. It is indicated that relativistic bulk motion of the gamma-ray-emitting plasma generically provides a solution to all three of these problems. Results show that, if the plasma that produces gamma-ray bursts has a bulk relativistic velocity with Lorentz factor gamma of about 10, several of the most troubling problems having to do with gamma-ray bursts are solved. 42 refs

  6. Radiation transport of cosmic ray nuclei in lunar material and radiation doses

    International Nuclear Information System (INIS)

    Silberberg, R.; Tsao, C.H.; Adams, J.H. Jr.; Letaw, J.R.

    1985-01-01

    The radiation environment on the lunar surface is inhospitable. The permanent settlers may work ten hours per 24-hour interval for the two-week-long lunar day on the lunar surface, or 20 percent of the total time. At moderate depths below the lunar surface (less than 200 g/sq cm) the flux of secondary neutrons exceeds considerably that in the upper atmosphere of the earth, due to cosmic-ray interactions with lunar material. The annual dose equivalent due to neutrons is about 20 or 25 rem within the upper meter of the lunar surface. The dose equivalent due to gamma rays generated by nuclear interactions near the lunar surface is only on the order of 1 percent of that due to neutrons. However, gamma-ray line emission from excited nuclei and nuclear spallation products generated by cosmic rays near the lunar surface is of considerable interest: these lines permit the partial determination of lunar composition by gamma spectroscopy. 12 references

  7. Gamma-ray effect on sweet potato

    International Nuclear Information System (INIS)

    Ferdes, O.; Ciofu, R.; Stroia, L.; Ghering, A.; Ferdes, M.

    1994-01-01

    The paper presents the results on modification occurred in biochemical properties of sweet potato (Ipomea batatus L.) after gamma irradiation. Two varieties, named Victoria Ianb (a white variety) and Portocaliu (a red variety), were selected and acclimatized for the agrometeorological conditions of Romania. The samples consist of roots from both usual and experimental crops. They were irradiated in batch, one week after harvesting, with a ICPR Co-60 gamma-ray source by approx. 370 TBq, dose range 100-500 Gy, dose rate 100±5 Gy/hour, dose uniformity ±5%, temperature 10 o C, 80±5% relative humidity (rh). The irradiation doses received were checked using the Fricke ferrous sulphate dosimeter procedure. The roots were kept two months at relative darkness, 6-11 o C, 60-75% rh and analyzed from time to time (initial, 5, 7, 14, 30 and 60 days). The following parameters are analyzed by conventional methods: total and reducing sugars (in De equivalent, %, on dry weight basis), starch content and the activities of sugar metabolizing enzymes. The red variety had a better behaviour towards irradiation that the white one. The sugar contents (both total and reducing), as well as starch, varied more in the white variety. The sugar metabolizing enzyme activities were influenced by both irradiation and storage conditions. Their activities were maximal at 200 and 300 Gy, and decreased significantly at higher doses. The activities also decreased in time, their variations being higher at lower doses (100 and 200 Gy). The results showed no significant influence of gamma irradiation on storage life. The modifications induced in sugar contents and enzyme activities had maximal effects at 200-300 Gy. (author)

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

    International Nuclear Information System (INIS)

    Kiskova, J.; Smajda, B.; Capicikova, M.; Lievajova, K.

    2006-01-01

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

  9. Highlights of GeV Gamma-Ray Astronomy

    Science.gov (United States)

    Thompson, David J.

    2010-01-01

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

  10. Comparative effects of gamma-rays and electron beams on peroxide formation in phosphatidylcholine

    International Nuclear Information System (INIS)

    Todoriki, S.; Hayashi, T.

    1994-01-01

    Phosphatidylcholine was irradiated in the state of a film or liposome with gamma-rays or electron beams, and the amount of peroxide was determined to compare the effects of the two types of radiation. The amounts of peroxide formed in both the film and liposome with gamma-rays were significantly larger than those with electron beams, when the samples were irradiated at the same dose. Proteins such as bacteriorhodopsin reduced the degree of peroxide formation in liposome, and the effect of gamma-rays was much larger than that of electron beams, even in the presence of protein. The results of the present investigation indicate that the effects of gamma-rays on peroxide formation in phosphatidylcholine were significantly larger than those of electron beams, irrespective of the state of the lipid

  11. Activation of wine bentonite with gamma rays

    International Nuclear Information System (INIS)

    Goranov, N.; Antonov, M.

    1997-01-01

    The action of gamma rays on wine bentonite as well as influence of its adsorption and technologic qualities on the composition and stability of wines against protein darkening and precipitation has been studied. The experiments were carried out with wine bentonite produced in the firm Bentonite and irradiated with doses of 0.4, 0.6, 0.8 and 1.0 MR. White and red wines have been treated with irradiated bentonite under laboratory conditions at 1.0 g/dm 3 . All samples are treated at the same conditions. The flocculation rate of the sediment was determined visually. Samples have been taken 24 h later from the cleared wine layers. The following parameters have been determined: clarification, filtration rate, phenolic compounds, calcium, colour intensity, total extracted substances, etc. The volume of the sediment has been determined also. The control samples have been taken from the same unirradiated wines. The results showed better and faster clarification in on the third, the 20th and the 24th hours with using of gamma-irradiated at doses 0.8 and 1.0 MR. The sediment was the most compact and its volume - the smallest compared to the samples treated with bentonite irradiated with doses of 0.6 and 0.4 MR. This ensures a faster clarification and better filtration of treated wines. The bentonite activated with doses of 0.8 and 1.0 MR adsorbs the phenolic compounds and the complex protein-phenolic molecules better. In the same time it adsorbs less extracted substances compared to untreated bentonite and so preserves all organoleptic properties of wine. The irradiated bentonite adsorbs less the monomers of anthocyan compounds which ensures brighter natural colour of wine. The gamma-rays activation consolidates calcium in the crystal lattice of bentonite particles and in this way eliminates the formation of crystal precipitates

  12. Localization of Gamma-Ray Bursts Using the Fermi Gamma-Ray Burst Monitor

    NARCIS (Netherlands)

    Connaughton, V.; Briggs, M.S.; Goldstein, A.; Meegan, C.A.; Paciesas, W.S.; Preece, R.D.; Wilson-Hodge, C.A.; Gibby, M.H.; Greiner, J.; Gruber, D.; Jenke, P.; Kippen, R.M.; Pelassa, V.; Xiong, S.; Yu, H-F.; Bhat, P.N.; Burgess, J.M.; Byrne, D.; Fitzpatrick, G.; Foley, S.; Giles, M.M.; Guiriec, S.; van der Horst, A.J.; von Kienlin, A.; McBreen, S.; McGlynn, S.; Tierney, D.; Zhang, B..B.

    2015-01-01

    The Fermi Gamma-ray Burst Monitor (GBM) has detected over 1400 gamma-ray bursts (GRBs) since it began science operations in 2008 July. We use a subset of over 300 GRBs localized by instruments such as Swift, the Fermi Large Area Telescope, INTEGRAL, and MAXI, or through triangulations from the

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

    DEFF Research Database (Denmark)

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

    2009-01-01

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

  14. Neutron and gamma ray attenuation of asphalt; Comparison with paraffin and water

    International Nuclear Information System (INIS)

    Abdul-Majid, S.; Kutbi, I.I.

    1996-01-01

    Asphalt is a low cost, readily available, easy-to-cast material which is rich in hydrogen and carbon, elements most effective for fast-neutron shielding. Unlike paraffin, the material can easily be mixed with boron containing compounds, an, element of high absorption cross-section for slow neutrons. The 241 Am-Be neutron and gamma attenuation characteristic of asphalt were studied. The source is having wide applications in industry and geophysics field work. Comparisons were made with paraffin and water. The source activity was 1.11 x 1,011 Bq (3 Ci) with a neutron emission rate of 6.6 x 106 n s -1 and a tolerance of +10%. The neutron dose-equivalent rate at 1 m was 66 mSv h -1 , while the associated gamma ray exposure was ∼1.9 mC kg -1 h -1 of the bare source. A neutron remmeter was used for the neutron dose-equivalent rate measurements, which produces an energy response that approximates human body dose equivalent over a wide range of neutron energy. An air filled ionization chamber was used for the exposure rate measurements. The slow neutrons were measured by a BF 3 gas filled detector. The shielding materials were confined in an aluminum cylinder of 1 mm wall thickness where the source was kept in the middle. The neutron dose rate, the gamma ray exposure rate, and the slow neutron count rate were measured at different shield radii and at different distances from its outer surface. The neutron doses of asphalt at the surface of cylindrical shields of 8, 12, 16, 20, and 24 cm radii in mSv h -1 were 0.85, 0.4, 0.25, 0.13, and 0.06, respectively, while the gamma ray exposure mC kg -1 h -1 were 7, 4.4 2.5, 1.3, and 0.88, respectively. The neutron dose rate attenuation of asphalt was very close to that of water, but slightly lower than that of paraffin, while the gamma ray attenuation was close to that of water but higher than that of paraffin

  15. Radiation-induced reduction of diuron by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Zhang Jibiao; Zheng Zheng; Zhao Tan; Zhao Yongfu; Wang Lianhong; Zhong Yun; Xu Yue

    2008-01-01

    Diuron degradation efficiencies and the proposed mechanism by gamma-ray irradiation were investigated. Several factors that might affect the degradation values were further examined. The UV absorbances at 200-400 nm and diuron concentration decreased with the increase of radiation dose. When diuron initial concentration was 18.5 mg L -1 and 1.0 kGy was selected as the radiation dose, diuron removal value and loss of total organic carbon were 100 and 34.1%, respectively. However, the concentration of Cl - ion increased with the increase of radiation dose. The process could be depicted by first order reaction kinetics and the reaction was mainly caused by the reaction of diuron with ·OH and e aq - . The degradation efficiency decreased with the increase of initial concentration at the same radiation dose. H 2 O 2 , HCO 3 - , NO 3 - , NO 2 - , CH 3 OH and humic acid as additives reduced the degradation efficiency. Furthermore, the increase of NO 3 - , NO 2 - , CH 3 OH and humic acid would result in the decrease of the degradation values. The pH value could affect the removal efficiency and the degradation process was enhanced in acid condition. The pH value became lower with increasing radiation dose after gamma-ray irradiation

  16. Calculation of gamma ray dose buildup factors in water for isotropic point, plane mono directional and line sources using MCNP code

    International Nuclear Information System (INIS)

    Atak, H.; Celikten, O. S.; Tombakoglu, M.

    2009-01-01

    Gamma ray dose buildup factors in water for isotropic point, plane mono directional and infinite/finite line sources were calculated using the MCNP code. The buildup factors are determined for gamma ray energies of 1, 2, 3 and 4 Mev and for shield thicknesses of 1, 2, 4 and 7 mean free paths. The calculated buildup factors were then fitted in the Taylor and Berger forms. For the line sources a buildup factor table was also constructed using the Sievert function and the constants in Taylor form derived in this study to compare with the Monte Carlo results. All buildup factors were compared with the tabulated data given in literature. In order to reduce the statistical errors on buildup factors, 'forced collision' option was used in the MCNP calculations.

  17. COSANI-2, Gamma Doses from SABINE Calculation, Activity from ANISN Flux Calculation

    International Nuclear Information System (INIS)

    Dupont, C.

    1975-01-01

    1 - Nature of physical problem solved: Retrieval of SABINE and/or ANISN results. Calculates in case of SABINE results the individual contributions of capture gamma rays in each region to the total gamma dose and to the total gamma heating may calculate in case of ANISN new activity rates starting from ANISN flux saved on tape and activity cross sections taken on an ANISN binary library tape. The program can draw on a BENSON plotter any of the following quantities: - group flux; - activity rates; - dose rates; - neutron spectra for SABINE; - neutron or gamma direct or adjoint spectra for ANISN; - gamma heating and dose rate for SABINE including individual contributions from each region. Several ANISN and/or SABINE cases can be drawn on the same graph for comparison purposes. 2 - Restrictions on the complexity of the problem: Maximum number of: - tapes containing ANISN and/or SABINE results: 5; - curves per graph: 3; - regions: 40; - points per curve: 500; - energy groups: 200

  18. Gamma ray shielding: a web based interactive program

    International Nuclear Information System (INIS)

    Subbaiah, K.V.; Senthi Kumar, C.; Sarangapani, R.

    2005-01-01

    A web based interactive computing program is developed using java for quick assessment of Gamma Ray shielding problems. The program addresses usually encountered source geometries like POINT, LINE, CYLINDRICAL, ANNULAR, SPHERICAL, BOX, followed by 'SLAB' shield configurations. The calculation is based on point kernel technique. The source points are randomly sampled within the source volume. From each source point, optical path traversed in the source and shield media up to the detector location is estimated to calculate geometrical and material attenuations, and then corresponding buildup factor is obtained, which accounts for scattered contribution. Finally, the dose rate for entire source is obtained by summing over all sampled points. The application allows the user to select one of the seven regular geometrical bodies and provision exist to give source details such as emission energies, intensities, physical dimensions and material composition. Similar provision is provided to specify shield slab details. To aid the user, atomic numbers, densities, standard build factor materials and isotope list with respective emission energies and intensity for ready reference are given in dropdown combo boxes. Typical results obtained from this program are validated against existing point kernel gamma ray shielding codes. Additional facility is provided to compute fission product gamma ray source strengths based on the fuel type, burn up and cooling time. Plots of Fission product gamma ray source strengths, Gamma ray cross-sections and buildup factors can be optionally obtained, which enable the user to draw inference on the computed results. It is expected that this tool will be handy to all health physicists and radiological safety officers as it will be available on the internet. (author)

  19. Gamma ray astronomy with COS-B

    International Nuclear Information System (INIS)

    Swanenburg, B.N.

    1981-01-01

    Observational results in the field of gamma-ray astronomy that have been obtained to date with the COS-B satellite are discussed and questions raised by these observations are summarized. Following a brief review of the instrumental characteristics of COS-B and the extent of COS-B gamma-ray coverage of the sky, particular attention is given to the questions raised by the discovery of many unidentified gamma-ray sources with no apparent optical, X-ray or radio counterparts and the detection of high-energy gamma radiation from the quasar 3C 273, which suggests the role of gamma-ray emission in the creation of other radiation

  20. Inverse Compton gamma-rays from pulsars

    International Nuclear Information System (INIS)

    Morini, M.

    1983-01-01

    A model is proposed for pulsar optical and gamma-ray emission where relativistic electrons beams: (i) scatter the blackbody photons from the polar cap surface giving inverse Compton gamma-rays and (ii) produce synchrotron optical photons in the light cylinder region which are then inverse Compton scattered giving other gamma-rays. The model is applied to the Vela pulsar, explaining the first gamma-ray pulse by inverse Compton scattering of synchrotron photons near the light cylinder and the second gamma-ray pulse partly by inverse Compton scattering of synchrotron photons and partly by inverse Compton scattering of the thermal blackbody photons near the star surface. (author)

  1. Impact of intense x-ray pulses on a NaI(Tl)-based gamma camera

    Science.gov (United States)

    Koppert, W. J. C.; van der Velden, S.; Steenbergen, J. H. L.; de Jong, H. W. A. M.

    2018-03-01

    In SPECT/CT systems x-ray and γ-ray imaging is performed sequentially. Simultaneous acquisition may have advantages, for instance in interventional settings. However, this may expose a gamma camera to relatively high x-ray doses and deteriorate its functioning. We studied the NaI(Tl) response to x-ray pulses with a photodiode, PMT and gamma camera, respectively. First, we exposed a NaI(Tl)-photodiode assembly to x-ray pulses to investigate potential crystal afterglow. Next, we exposed a NaI(Tl)-PMT assembly to 10 ms LED pulses (mimicking x-ray pulses) and measured the response to flashing LED probe-pulses (mimicking γ-pulses). We then exposed the assembly to x-ray pulses, with detector entrance doses of up to 9 nGy/pulse, and analysed the response for γ-pulse variations. Finally, we studied the response of a Siemens Diacam gamma camera to γ-rays while exposed to x-ray pulses. X-ray exposure of the crystal, read out with a photodiode, revealed 15% afterglow fraction after 3 ms. The NaI(Tl)-PMT assembly showed disturbances up to 10 ms after 10 ms LED exposure. After x-ray exposure however, responses showed elevated baselines, with 60 ms decay-time. Both for x-ray and LED exposure and after baseline subtraction, probe-pulse analysis revealed disturbed pulse height measurements shortly after exposure. X-ray exposure of the Diacam corroborated the elementary experiments. Up to 50 ms after an x-ray pulse, no events are registered, followed by apparent energy elevations up to 100 ms after exposure. Limiting the dose to 0.02 nGy/pulse prevents detrimental effects. Conventional gamma cameras exhibit substantial dead-time and mis-registration of photon energies up to 100 ms after intense x-ray pulses. This is due PMT limitations and due to afterglow in the crystal. Using PMTs with modified circuitry, we show that deteriorative afterglow effects can be reduced without noticeable effects on the PMT performance, up to x-ray pulse doses of 1 nGy.

  2. Plastic nuclear track detectors as high x-ray and gamma dosimeters

    International Nuclear Information System (INIS)

    Chong Chon Sing

    1995-01-01

    A brief review of recent studies on the effects of high doses of x-ray and gamma ray on the track registration properties of several plastic track detectors is presented. The bulk etching rates and the etched track sizes have been found to increase with the dose in the range up to 100 Mrad. These results suggest that the changes in track registration characteristics can be employed as an index of the radiation dose in the megarad region. In particular, recent results on the effect of X-ray irradiation on two types of cellulose nitrate track detectors obtained in our laboratory are reported in this paper. (author)

  3. A point-kernel shielding code for calculations of neutron and secondary gamma-ray 1cm dose equivalents: PKN

    International Nuclear Information System (INIS)

    Kotegawa, Hiroshi; Tanaka, Shun-ichi

    1991-09-01

    A point-kernel integral technique code, PKN, and the related data library have been developed to calculate neutron and secondary gamma-ray dose equivalents in water, concrete and iron shields for neutron sources in 3-dimensional geometry. The comparison between calculational results of the present code and those of the 1-dimensional transport code ANISN = JR, and the 2-dimensional transport code DOT4.2 showed a sufficient accuracy, and the availability of the PKN code has been confirmed. (author)

  4. TU-H-CAMPUS-TeP3-04: Probing the Dose Enhancement Due to a Clinically-Relevant Concentration of Gold Nanoparticles and Yb-169 Gamma Rays Using PRESAGE Dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Cho, J [UT MD Anderson Cancer Center, Houston, TX (United States); Oklahoma State University, Stillwater, OK (United States); Alqathami, M; Cho, S [UT MD Anderson Cancer Center, Houston, TX (United States); Reynoso, F [UT MD Anderson Cancer Center, Houston, TX (United States); Washington University School of Medicine, St. Louis, MO (United States)

    2016-06-15

    Purpose: To probe physical evidences of the dose enhancement due to a low/clinically-relevant concentration of gold nanoparticles (GNPs) and Yb-169 gamma rays using PRESAGE dosimeters. Methods: A PRESAGE cuvette was placed at approximately 2 mm above the plane containing three novel Yb-169 brachytherapy seeds (3.2, 3.2, and 5.3 mCi each). Two types of PRESAGE dosimeters were used – plain PRESAGEs (controls) and PRESAGEs loaded with 0.02 wt. % of GNPs (GNP-PRESAGEs). Each PRESAGE dosimeter was irradiated with different time durations (0 to 24 hours) to deliver 0, 4, 8, 16 and 24 Gy of dose. For a reference/comparison, both types of PRESAGEs were also irradiated using 250 kVp x-rays with/without Er-filter to deliver 0, 3, 10, and 30 Gy of dose. Er-filter was used to emulate Yb-169 spectrum using 250 kVp x-rays. The absorption spectra of PRESAGEs were measured using a UV spectrophotometer and used to determine the corresponding optical densities (ODs). Results: GNP-PRESAGEs exposed to Yb-169 sources showed ∼65% increase in ODs compared with controls. When exposed to Er-filtered and unfiltered 250 kVp x-rays, they produced smaller increases in ODs, ∼41% and ∼37%, respectively. There was a linear relationship between ODs and delivered doses with a goodness-of-fit (R2) greater than 0.99. Conclusion: A notable increase in the ODs (∼65%) was observed for GNP-PRESAGEs irradiated by Yb-169 gamma rays. Considering the observed OD increases, it was highly likely that Yb-169 gamma rays were more effective than both Er-filtered and unfiltered 250 kVp x-rays, in terms of producing the dose enhancement. Due to several unknown factors (e.g., possible difference in the dose response of GNP-PRESAGEs vs. PRESAGEs), however, a further investigations is necessary to establish the feasibility of quantifying the exact amount of macroscopic or microscopic/local GNP-mediated dose enhancement using PRESAGE or similar volumetric dosimeters. Supported by DOD/PCRP grant W81XWH-12

  5. Planetary gamma-ray spectroscopy: the effects of hydrogen absorption cross-section of the gamma-ray spectrum

    International Nuclear Information System (INIS)

    Lapides, J.R.

    1981-01-01

    The gamma-ray spectroscopy of planet surfaces is one of several possible methods that are useful in determining the elemental composition of planet surfaces from orbiting spacecraft. This has been demonstrated on the Apollos 15 and 16 missions as well as the Soviet Mars-5 mission. Planetary gamma-ray emission is primarily the result of natural radioactive decay and cosmic-ray and solar-flare-induced nuclear reactions. Secondary neutron reactions play a large role in the more intense gamma-ray emission. The technique provides information on the elemental composition of the top few tens of centimeters of the planet surface. Varying concentrations of hydrogen and compositional variations that alter the macroscopic thermal-neutron absorption cross section have a significant effect on the neutron flux in the planet surface and therefore also on the gamma-ray emission from the surface. These effects have been systematically studied for a wide range of possible planetary compositions that include Mercury, the moon, Mars, the comets, and the asteroids. The problem of the Martian atmosphere was also investigated. The results of these calculations, in which both surface neutron fluxes and gamma-ray emission fluxes were determined, were used to develop general procedures for obtaining planet compositions from the gamma-ray spectrum. Several changes have been suggested for reanalyzing the Apollos 15 and 16 gamma-ray results. In addition, procedures have been suggested that can be applied to neutron-gamma techniques in mineral and oil exploration

  6. Action of minute dosis of gamma rays on gestation of mice

    International Nuclear Information System (INIS)

    Templier, J.; Maudouyt, M.A.; Charpenteau, M.; Bonnet, J.

    1978-01-01

    Female mice were irradiated with 10 rads of 60 Co gamma ray, 7 hours after mating. This low dose induces a decrease in implantation number, and alive foetus number and is followed by a lower number of corpora lutea. These results to seem to show an effect of gamma irradiation on ovary and embryonic development [fr

  7. Gamma Ray Bursts-Afterglows and Counterparts

    Science.gov (United States)

    Fishman, Gerald J

    1998-01-01

    Several breakthrough discoveries were made last year of x-ray, optical and radio afterglows and counterparts to gamma-ray bursts, and a redshift has been associated with at least one of these. These discoveries were made possible by the fast, accurate gamma-ray burst locations of the BeppoSAX satellite. It is now generally believed that the burst sources are at cosmological distances and that they represent the most powerful explosions in the Universe. These observations also open new possibilities for the study of early star formation, the physics of extreme conditions and perhaps even cosmology. This session will concentrate on recent x-ray, optical and radio afterglow observations of gamma-ray bursts, associated redshift measurements, and counterpart observations. Several review and theory talks will also be presented, along with a summary of the astrophysical implications of the observations. There will be additional poster contributions on observations of gamma-ray burst source locations at wavelengths other than gamma rays. Posters are also solicited that describe new observational capabilities for rapid follow-up observations of gamma-ray bursts.

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

    International Nuclear Information System (INIS)

    Tajima, Makoto; Hossain, Tarib.

    1989-01-01

    Eleven kinds of commercial spices were irradiated with gamma-ray at the dose of 0 to 5 kGy. The microbial counts of almost all the samples were decreased under 10 3 /g by the dose of 5 kGy. The D 10 value of microbials contaminated to these spices were 1.1 to 4.3. Five kGy of gamma-ray irradiation affected to the recoveries of essencial oil from the spices. The effect was varied between spices. While the recoveries from some spices were increased, the others were decreased. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Tajima, Makoto (National Food Research Inst., Tsukuba, Ibaraki (Japan)); Hossain, Tarib

    1989-11-01

    Eleven kinds of commercial spices were irradiated with gamma-ray at the dose of 0 to 5 kGy. The microbial counts of almost all the samples were decreased under 10{sup 3}/g by the dose of 5 kGy. The D{sub 10} value of microbials contaminated to these spices were 1.1 to 4.3. Five kGy of gamma-ray irradiation affected to the recoveries of essencial oil from the spices. The effect was varied between spices. While the recoveries from some spices were increased, the others were decreased. (author).

  10. About cosmic gamma ray lines

    Science.gov (United States)

    Diehl, Roland

    2017-06-01

    Gamma ray lines from cosmic sources convey the action of nuclear reactions in cosmic sites and their impacts on astrophysical objects. Gamma rays at characteristic energies result from nuclear transitions following radioactive decays or high-energy collisions with excitation of nuclei. The gamma-ray line from the annihilation of positrons at 511 keV falls into the same energy window, although of different origin. We present here the concepts of cosmic gamma ray spectrometry and the corresponding instruments and missions, followed by a discussion of recent results and the challenges and open issues for the future. Among the lessons learned are the diffuse radioactive afterglow of massive-star nucleosynthesis in 26Al and 60Fe gamma rays, which is now being exploited towards the cycle of matter driven by massive stars and their supernovae; large interstellar cavities and superbubbles have been recognised to be of key importance here. Also, constraints on the complex processes making stars explode as either thermonuclear or core-collapse supernovae are being illuminated by gamma-ray lines, in this case from shortlived radioactivities from 56Ni and 44Ti decays. In particular, the three-dimensionality and asphericities that have recently been recognised as important are enlightened in different ways through such gamma-ray line spectroscopy. Finally, the distribution of positron annihilation gamma ray emission with its puzzling bulge-dominated intensity disctribution is measured through spatially-resolved spectra, which indicate that annihilation conditions may differ in different parts of our Galaxy. But it is now understood that a variety of sources may feed positrons into the interstellar medium, and their characteristics largely get lost during slowing down and propagation of positrons before annihilation; a recent microquasar flare was caught as an opportunity to see positrons annihilate at a source.

  11. Incidence of leukemia among atomic bomb survivors in relation to neutron and gamma dose, Hiroshima and Nagasaki, 1950-71

    International Nuclear Information System (INIS)

    Ishimaru, Toranosuke; Otake, Masanori; Ichimaru, Michito.

    1978-03-01

    The incidence of leukemia during 1950-71 in the fixed mortality sample of atomic bomb survivors in Hiroshima and Nagasaki has been analyzed as a function of individual gamma and neutron kerma and marrow dose. Two dose response models were tested for each of acute leukemia, chronic granulocytic leukemia, and all types of leukemia, respectively. Each model postulates that leukemia incidence depends upon the sum of the separate risks imposed by the gamma ray and neutron doses; in Model I both are assumed to be directly proportional to the respective doses, while Model II assumes that while the risk from neutrons is directly proportional to the dose, the risk from gamma rays is proportional to dose-squared. Weighted regression analyses were performed for each model. When the two models were fitted to the data for all types of leukemia, the estimated regression coefficients corresponding to the neutron and gamma ray doses both differed significantly from zero, for each model. However, when analysis was restricted to acute leukemia, both the neutron and gamma ray coefficients were significant only for Model II, and with respect to chronic granulocytic leukemia, only the coefficient of the neutron dose was significant, using either Model I or Model II. It appeared that the responses of the two leukemia types differed by type of radiation. If the chronic granulocytic and acute leukemias are considered together, the Model II appears to fit the data slightly better than Model I, but neither models is rejected by the data. (author)

  12. Effects of gamma-rays irradiation on tracking resistance of organic insulating materials

    Energy Technology Data Exchange (ETDEWEB)

    Du, Boxue; Suzuki, Akio; Kobayashi, Shigeo [Tokyo Univ. of Agriculture and Technology, Koganei (Japan). Faculty of Technology

    1996-04-01

    This paper describes the influence of gamma-rays irradiation on tracking failure of organic insulating materials by use of the IEC Publ.112 method. Tracking resistance of organic insulating materials under wet polluted condition has been studied by many investigators with a test method of the IEC Publ.112. The investigations on irradiation effects on tracking resistance should be enhanced due to the increasing usage of organic insulating materials in the radiation environments. The tracking resistance seems to be affected by gamma-irradiation, but the knowledge on the influence of gamma-irradiation is quite a few and systematic studies are needed. In this paper, modified polyphenylene oxide, polybutylene naphthalate, modified polycarbonate and polybutylene terephthalate which were irradiated in air until 1x10{sup 7}R and 1x10{sup 8}R with dose rate of 10{sup 6}R/hr using {sup 60}Co gamma-source have been employed. The total dose effects on the number of drops to tracking failure, contact angle and charges of scintillation have been studied. As the total doses are increased, the number of drops to tracking failure decreases with polybutylene terephthalate. On the other hand, the number of drops to tracking failure increases with polybutylene naphthalate and modified polycarbonate when the total doses are increased. The effects of gamma-rays irradiation on tracking failure are due to radiation-induced degradation or cross-linking of organic insulating materials. When the organic insulating materials are degraded by gamma-irradiation, the tracking resistance decreases, but for cross-linking type materials, the tracking resistance increases. (author)

  13. Lunar occultations for gamma-ray source measurements

    Science.gov (United States)

    Koch, David G.; Hughes, E. B.; Nolan, Patrick L.

    1990-01-01

    The unambiguous association of discrete gamma-ray sources with objects radiating at other wavelengths, the separation of discrete sources from the extended emission within the Galaxy, the mapping of gamma-ray emission from nearby galaxies and the measurement of structure within a discrete source cannot presently be accomplished at gamma-ray energies. In the past, the detection processes used in high-energy gamma-ray astronomy have not allowed for good angular resolution. This problem can be overcome by placing gamma-ray detectors on the moon and using the horizon as an occulting edge to achieve arcsec resolution. For purposes of discussion, this concept is examined for gamma rays above 100 MeV for which pair production dominates the detection process and locally-generated nuclear gamma rays do not contribute to the background.

  14. Future prospects for. gamma. -ray astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Fichtel, C [National Aeronautics and Space Administration, Greenbelt, MD (USA). Goddard Space Flight Center

    1981-06-30

    As ..gamma..-ray astronomy moves from the discovery to the exploratory phase, the promise of ..gamma..-ray astrophysics noted by theorists in the late 1940s and 1950s is beginning to be realized. In the future, satellites should carry instruments that will have over an order of magnitude greater sensitivity than those flown thus far, and, for at least some portions of the ..gamma..-ray energy range, these detectors will also have substantially improved energy and angular resolution. The information to be obtained from these experiments should greatly enhance our knowledge of several astrophysical phenomena including the very energetic and nuclear processes associated with compact objects, astrophysical nucleosynthesis, solar particle acceleration, the chemical composition of the planets and other bodies of the Solar System, the structure of our Galaxy, the origin and dynamic pressure effects of the cosmic rays, high energy particles and energetic processes in other galaxies especially active ones, and the degree of matter-antimatter symmetry of the Universe. The ..gamma..-ray results of the forthcoming programs such as Gamma-I, the Gamma Ray Observatory, the ..gamma..-ray burst network, Solar Polar, and very high energy ..gamma..-ray telescopes on the ground will almost certainly provide justification for more sophisticated telescopes. These advanced instruments might be placed on the Space Platform currently under study by N.A.S.A.

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

    International Nuclear Information System (INIS)

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

    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

  16. Gamma radiation and gamma ray protection factors of ships in various situations of radioactive fall-out

    International Nuclear Information System (INIS)

    Brehm, E.H.; Holst, T.

    1975-01-01

    In this report the development of methods of evaluating gamma ray protection factors (GSF) of ships for various situations of radioactive fall-out is described. The joining calculations of gamma ray protection factors are performed by the newly developed computer procedure GASUFA. These protection factors determine - in connection with a measured gamma radiation dose at a given detector point - the gamma radiation in different compartments of the ships. The computer program GASUFA is able to perform calculations considering the dependence of energy, place and time for the following situations: - the ship is under a radioactive cloud without fall-out; - the ship is under a radioactive cloud with fall-out; - the ship is contaminated by radioactive fall-out; - the clean or decontaminated ship is going through a zone, which is contaminated by radioactive fall-out; - the ship and the surrounding water surface are contaminated by radioactive fall-out. (orig.) [de

  17. Radio Observations of Gamma-ray Novae

    Science.gov (United States)

    Linford, Justin D.; Chomiuk, L.; Ribeiro, V.; project, E.-Nova

    2014-01-01

    Recent detection of gamma-ray emission from classical novae by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope surprised many in the astronomical community. We present results from radio observations, obtained using the Karl G. Jansky Very Large Array (VLA), of three gamma-ray novae: Mon2012, Sco2012, and Del2013. Radio observations allow for the calculation of ejecta masses, place limits on the distances, and provide information about the gamma-ray emission mechanism for these sources.

  18. The Gamma-Ray Imager GRI

    Science.gov (United States)

    Wunderer, Cornelia B.; GRI Collaboration

    2008-03-01

    Observations of the gamma-ray sky reveal the most powerful sources and the most violent events in the Universe. While at lower wavebands the observed emission is generally dominated by thermal processes, the gamma-ray sky provides us with a view on the non-thermal Universe. Here particles are accelerated to extreme relativistic energies by mechanisms which are still poorly understood, and nuclear reactions are synthesizing the basic constituents of our world. Cosmic accelerators and cosmic explosions are major science themes that are addressed in the gamma-ray regime. ESA's INTEGRAL observatory currently provides the astronomical community with a unique tool to investigate the sky up to MeV energies and hundreds of sources, new classes of objects, extraordinary views of antimatter annihilation in our Galaxy, and fingerprints of recent nucleosynthesis processes have been discovered. NASA's GLAST mission will similarly take the next step in surveying the high-energy ( GeV) sky, and NuSTAR will pioneer focusing observations at hard X-ray energies (to 80 keV). There will be clearly a growing need to perform deeper, more focused investigations of gamma-ray sources in the 100-keV to MeV regime. Recent technological advances in the domain of gamma-ray focusing using Laue diffraction and multilayer-coated mirror techniques have paved the way towards a gamma-ray mission, providing major improvements compared to past missions regarding sensitivity and angular resolution. Such a future Gamma-Ray Imager will allow the study of particle acceleration processes and explosion physics in unprecedented detail, providing essential clues on the innermost nature of the most violent and most energetic processes in the Universe.

  19. AIRGAMMA, External Gamma-Ray Exposure from Radioactive Cloud

    International Nuclear Information System (INIS)

    Hidaka, Akihide; Iijima, Tshinori

    1989-01-01

    1 - Description of program or function: AIRGAMMA calculates quickly the external exposure to gamma rays from a radioactive cloud. 2 - Method of solution: The external exposure is calculated by interpolating the normalized doses providing on the basis of the Gaussian plume model. 3 - Restrictions on the complexity of the problem: Memory requirement is 30 Kbytes

  20. Observation of gamma-ray bursts with GINGA

    International Nuclear Information System (INIS)

    Murakami, Toshio; Fujii, Masami; Nishimura, Jun

    1989-01-01

    Gamma-ray Burst Detector System (GBD) on board the scientific satellite 'GINGA' which was launched on Feb. 5, 1987, was realized as an international cooperation between ISAS and LANL. It has recorded more than 40 Gamma-Ray Burst candidates during 20 months observation. Although many observational evidences were accumulated in past 20 years after the discovery of gamma-ray burst by LANL scientists, there are not enough evidence to determine the origin and the production mechanism of the gamma-ray burst. GBD consists of a proportional counter and a NaI scintillation counter so that it became possible to observe energy spectrum of the gamma-ray burst with high energy resolution over wide range of energy (1.5-380 keV) together with high time resolution. As the result of observation, the following facts are obtained: (1) A large fraction of observed gamma-ray bursts has a long X-ray tail after the harder part of gamma-ray emission has terminated. (2) Clear spectral absorption features with harmonic in energy was observed in some of the energy spectrum of gamma-ray bursts. These evidences support the hypothesis that the strongly magnetized neutron star is the origin of gamma-ray burst. (author)

  1. Gamma ray astronomy from satellites and balloons

    International Nuclear Information System (INIS)

    Schoenfelder, V.

    1986-01-01

    A survey is given of gamma ray astronomy topics presented at the Cosmic Ray Conference. The major conclusions at the Cosmic Ray Conference in the field of gamma ray astronomy are given. (1) MeV-emission of gamma-ray bursts is a common feature. Variations in duration and energy spectra from burst to burst may explain the discrepancy between the measured log N - log S dependence and the observed isotropy of bursts. (2) The gamma-ray line at 1.809 MeV from Al(26) is the first detected line from a radioactive nucleosynthesis product. In order to understand its origin it will be necessary to measure its longitude distribution in the Milky Way. (3) The indications of a gamma-ray excess found from the direction of Loop I is consistent with the picture that the bulk of cosmic rays below 100 GeV is produced in galactic supernova remnants. (4) The interpretation of the large scale distribution of gamma rays in the Milky Way is controversial. At present an extragalactic origin of the cosmic ray nuclei in the GeV-range cannot be excluded from the gamma ray data. (5) The detection of MeV-emission from Cen A is a promising step towards the interesting field of extragalactic gamma ray astronomy

  2. Radon emanation and soil moisture effects on airborne gamma-ray measurements

    International Nuclear Information System (INIS)

    Grasty, R.L.

    1997-01-01

    A theoretical model is developed to explain variations in airborne gamma-ray measurements over a calibration range near Ottawa, Ontario. The gamma-ray flux from potassium and the thorium decay series showed an expected decrease with increasing soil moisture. However, the gamma-ray flux from the uranium decay series was highest in the spring when the ground was water-saturated and even covered with snow. These results are explained through the build-up of radon and its associated gamma-ray-emitting decay products in the clay soil of the calibration range with increasing soil moisture. Similar results were found from airborne measurements over other clay soils. However, measurements over sandy soils showed that the count rates from all three radio elements increased with decreasing soil moisture. This difference between soil types was attributed to the lower radon emanation of the more coarse-grained sandy soils compared to finer-grained clay soils. The theoretical and experimental results demonstrate that any estimate of the natural gamma-ray field caused by radium in the ground must take into consideration the radon emanation coefficient of the soil. The radon diffusion coefficient of the soil must also be considered since it depends strongly on soil moisture. This has significant implications for the assessment of outdoor radiation doses using laboratory analyses of soil samples and the use of ground and airborne gamma-ray measurements for radon potential mapping

  3. The effects of gamma rays and genotypes on sunflower organogenesis traits [Helianthus annuus L.

    International Nuclear Information System (INIS)

    Rachid Al-Chaarani, G.; Gentzbittel, L.; Berrault, G.; Lenoble, S.; Sarrafi, A.

    2004-01-01

    Seeds of two inbred lines (AS613 and AS616) and their hybrid were irradiated with seven gamma rays doses (5, 15, 25, 35, 45, 55 and 65 Grays). Organogenesis traits were studied for all irradiated seeds as well as non irradiated ones used as control. The experiment was designed as a randomized complete block with three replications. Each replication consisted of 16 Petri dishes with four explants per gamma rays dose and per genotype. The regeneration ability of genotypes and the effects of gamma rays on regeneration were scored by assessing the percentage of explants forming shoots (ES/100E), the average number of shoots per explant shooting (S/ES) and the average number of shoots per explant plated (S/E). Genetic variability was observed among the three genotypes for all studied traits. The effect of irradiation and the interaction between genotype and irradiation were also significant for all the studied traits. Heterosis, when the hybrid was compared with the mean of the two parents, was significant for the different gamma rays doses in all traits except for 15 and 55 Grays, which were not significant for the percentage of explants forming shoots (ES/100E). Seed irradiation by 5 and 15 Grays is likely to have a significant effect by increasing the regeneration ability by cotyledon culture in sunflower [it

  4. NEW FERMI-LAT EVENT RECONSTRUCTION REVEALS MORE HIGH-ENERGY GAMMA RAYS FROM GAMMA-RAY BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Atwood, W. B. [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Baldini, L. [Universita di Pisa and Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bregeon, J.; Pesce-Rollins, M.; Sgro, C.; Tinivella, M. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bruel, P. [Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, Palaiseau (France); Chekhtman, A. [Center for Earth Observing and Space Research, College of Science, George Mason University, Fairfax, VA 22030 (United States); Cohen-Tanugi, J. [Laboratoire Univers et Particules de Montpellier, Universite Montpellier 2, CNRS/IN2P3, F-34095 Montpellier (France); Drlica-Wagner, A.; Omodei, N.; Rochester, L. S.; Usher, T. L. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Granot, J. [Department of Natural Sciences, The Open University of Israel, 1 University Road, P.O. Box 808, Ra' anana 43537 (Israel); Longo, F. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Razzaque, S. [Department of Physics, University of Johannesburg, Auckland Park 2006 (South Africa); Zimmer, S., E-mail: melissa.pesce.rollins@pi.infn.it, E-mail: nicola.omodei@stanford.edu, E-mail: granot@openu.ac.il [Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm (Sweden)

    2013-09-01

    Based on the experience gained during the four and a half years of the mission, the Fermi-LAT Collaboration has undertaken a comprehensive revision of the event-level analysis going under the name of Pass 8. Although it is not yet finalized, we can test the improvements in the new event reconstruction with the special case of the prompt phase of bright gamma-ray bursts (GRBs), where the signal-to-noise ratio is large enough that loose selection cuts are sufficient to identify gamma rays associated with the source. Using the new event reconstruction, we have re-analyzed 10 GRBs previously detected by the Large Area Telescope (LAT) for which an X-ray/optical follow-up was possible and found four new gamma rays with energies greater than 10 GeV in addition to the seven previously known. Among these four is a 27.4 GeV gamma ray from GRB 080916C, which has a redshift of 4.35, thus making it the gamma ray with the highest intrinsic energy ({approx}147 GeV) detected from a GRB. We present here the salient aspects of the new event reconstruction and discuss the scientific implications of these new high-energy gamma rays, such as constraining extragalactic background light models, Lorentz invariance violation tests, the prompt emission mechanism, and the bulk Lorentz factor of the emitting region.

  5. X-ray and gamma radiography devices

    International Nuclear Information System (INIS)

    Abdul Nassir Ibrahim; Azali Muhammad; Ab. Razak Hamzah; Abd. Aziz Mohamed; Mohamad Pauzi Ismail

    2008-01-01

    When we are using this technique, we also must familiar with the device and instrument that used such as gamma projector, crawler, x-ray tubes and others. So this chapter discussed detailed on device used for radiography work. For the x-ray and gamma, their characteristics are same but the source to produce is a big different. X-ray produced from the machine meanwhile, gamma produce from the source such as Co-60 and IR-192. Both are electromagnetic waves. So, the reader can have some knowledge on what is x-ray tube, discrete x-ray and characteristic x-ray, how the machine works and how to control a machine, what is source for gamma emitter, how to handle the projector and lastly difference between x-ray and gamma. Of course this cannot be with the theory only, so detailed must be learned practically.

  6. Standardization of high-dose measurement of electron and gamma ray absorbed doses and dose rates

    International Nuclear Information System (INIS)

    McLaughlin, W.L.

    1985-01-01

    Intense electron beams and gamma radiation fields are used for sterilizing medical devices, treating municipal wastes, processing industrial goods, controlling parasites and pathogens, and extending the shelf-life of foods. Quality control of such radiation processes depends largely on maintaining measurement quality assurance through sound dosimetry procedures in the research leading to each process, in the commissioning of that process, and in the routine dose monitoring practices. This affords documentation as to whether satisfactory dose uniformity is maintained throughout the product and throughout the process. Therefore, dosimetry at high doses and dose rates must in many radiation processes be standardized carefully, so that 'dosimetry release' of a product is verified. This standardization is initiated through preliminary dosimetry intercomparison studies such as those sponsored recently by the IAEA. This is followed by establishing periodic exercises in traceability to national or international standards of absorbed dose and dose rate. Traceability is achieved by careful selection of dosimetry methods and proven reference dosimeters capable of giving sufficiently accurate and precise 'transfer' dose assessments: (1) they must be calibrated or have well-established radiation-yield indices; (2) their radiation response characteristics must be reproducible and cover the dose range of interest; (3) they must withstand the rigours of back-and-forth mailing between a central standardizing laboratory and radiation processing facilities, without excessive errors arising due to instabilities, dosimeter batch non-uniformities, and environmental and handling stresses. (author)

  7. Systematics of gamma-ray energy spectra for classification of workplaces around a nuclear facility

    International Nuclear Information System (INIS)

    Urabe, Itsumasa; Tsujimoto, Tadashi; Katsurayama, Kousuke

    1988-01-01

    Radiation dosimetry in workplaces has been carried out both for assurance of the doses complying with the acceptable values and for improvement of protection methods to minimise detriments of the exposed population. This means that it is very important not only to determine dosimetric quantities in workplaces but also to know features of radiation levels because information for radiation protection can often be derived from the radiometric quantities. Classification of workplaces based on the feature of gamma-ray energy spectra is one of the practical ways to realise radiation protection being taken into consideration of the radiometric quantities. Furthermore, demarcation of workplaces based on these radiometric quantities may be effective for improvement of radiation protection practice such as estimation of radiation doses, designing of radiation shields and other activities. From these points of view, gamma-ray energy spectra have been determined in various workplaces in nuclear facilities, and systematics of gamma-ray fields were tried for classification of workplaces on the basis of the feature appeared in health physical quantities such as effective dose equivalents and responses of dosemeters

  8. Gamma-ray induced variation in the development of S. Khasianum Clarke

    International Nuclear Information System (INIS)

    Chauhan, Y.S.

    1978-01-01

    Present study deals with the effect of gamma ray exposures (10, 15, 20 and 25 kR) on the plant development in S. Khasianum Clarke. While 25 kR exposure dose was lethal, other exposures affected the development of various plant parts e.g. height, number of branches, and leaf forming capacity. Gamma rays also affected spine number, spine intensity and spine size on the leaves of this plant. Although flowering occurred almost simultaneously both in the control and treated plants, yield, number of berries and weight of the berry were affected. (author)

  9. Investigation Study on Gamma Ray Imaging Technology for Nuclear Power Plant Decommissioning

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Guk; Jeong, Woo Tae [Machinery and Materials Laboratory, Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

    2014-10-15

    The gamma ray imaging system provides an estimated dose-rate of the source at 30 cm above. The gamma detector is a terbium activated glass scintillator. The system is capable of producing a color two dimensional image of a radiation field superimposed on a black and white visual image. The system used in US power plants consists of a portable sensor head that contains both gamma ray and visual imaging systems and a portable control computer. The gamma ray imaging system has been successfully used as an ALARA tool for identifying source terms and determining the adequacy of existing shielding. Because the control system can be positioned away from the camera, the radiation exposure to personnel can be reduced without extensive shielding requirements. The gamma ray imaging system has been used to date in the decommissioning of Maine Yankee, Big Rock point,Trojan, San Onofre1, and Millstone 1. The equipment has also been used at normal refueling outages at a number of commercial nuclear power plants and at several Department of Energy Decommissioning sites. This paper is intended to review the applicability of gamma ray imaging system as decommissioning tool. In order to review the actual applicability, we are going to introduce applications for US power plants.

  10. Gamma-ray mutagenic effect on adzuki bean and the optimum dose

    International Nuclear Information System (INIS)

    Shen Huifang; Li Guozhu

    2012-01-01

    Dry seeds of three kinds of adzuki beans (Jinhong1, Jihong9218, and Jingnong6) were irradiated by 60 Co γ-rays to 100, 200, 300, 400, 500 and 600 Gy. The radiation effects on seedlings were analyzed to estimate the optimum dose, which was 400 to 600 Gy, based on the average half lethal dose (LD 50 ) of 473.3 Gy for the three kinds of adzuki beans. The M 1 γ-ray mutagenic effects were studied by farming the three kinds of adzuki beans irradiated to 350, 500 and 650 Gy. It was found that the beans treated with higher doses had obvious inhibition on germination rate, seedling development, with significant or very significant difference compared with the CK. There was significantly negative correlation between seedling emergences, seedling height and doses. Irradiation affected mature plants by reducing plant height, decreasing nodes number of main stem, pods number per plant, seeds per pod and shortening pod length with significant. The order of radio-sensitivity to γ-rays was as follows: Jinhong1, Jihong9218, and Jingnong6. (authors)

  11. Linear optical absorption response of poly(vinylidene fluoride - trifluoroethylene) copolymers to high gamma dose

    International Nuclear Information System (INIS)

    Medeiros, Adriana S.

    2009-01-01

    Poly(vinylidene fluoride) [PVDF] is a semicrystalline linear homopolymer composed by the repetition of CH 2 - CF 2 monomers. The Poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] is a copolymer which is obtained with the random introduction of fluorinated CHF-CF 2 monomers in the PVDF main chain. PVDF, and also its copolymers with TrFE contents ranging from 18 to 63 wt. %, have long been studied for their striking ferroelectric properties and their applications in actuators, transducers and ferroelectric memory. Recent research work around the world have demonstrated that, for TrFE contents ranging from with 30 to 50 wt. %, the copolymer can have its ferroelectric properties modified by high doses of ionizing radiation, with the appearing of radio-induced relaxor ferroelectric features. These studies have lead us to investigate the possible use of these copolymers as high dose dosemeters, once the reported amount of induced C=C conjugated bonds after X-ray, UV and gamma irradiation seems to be a function of the delivered radiation dose. In a first investigation for doses ranging from 0.1 to 100 kGy we found out a linear relation between the gamma radiation dose and the absorption peak intensities in the UV region of the spectrum, i.e., at 223 and 274 nm. The absorption peak at 223 nm is the most sensitive to gamma rays and can be used for detecting gamma doses ranging from 0.3 to 75 kGy. Simultaneously, the absorption peak at 274 nm can be used for doses ranging from 1 to 100 kGy. Now, in the present work, we extended the investigation to gamma doses up to 3 MGy. Particularly, this study is focused in the optical absorption peak at 274 nm, corresponding to the radio-induction of triplets of conjugated C=C double bonds. The investigation revealed a linear correlation between the gamma dose and peak intensity at 274 nm for gamma doses ranging from 0.1 to more than 750 KGy, with a huge extension of the original usable dose range. Calorimetric data revealed a

  12. Processing of gamma-ray spectrometric logs

    International Nuclear Information System (INIS)

    Umiastowski, K.; Dumesnil, P.

    1984-10-01

    CEA (Commissariat a l'Energie Atomique) has developped a gamma-ray spectrometric tool, containing an analog-to-digital converter. This new tool permits to perform very precise uranium logs (natural gamma-ray spectrometry), neutron activation logs and litho-density logs (gamma-gamma spectrometric logs). Specific processing methods were developped to treate the particular problems of down-hole gamma-ray spectrometry. Extraction of the characteristic gamma-ray peak, even if they are superposed on the background radiation of very high intensity, is possible. This processing methode enables also to obtain geological informations contained in the continuous background of the spectrum. Computer programs are written in high level language for SIRIUS (VICTOR) and APOLLO computers. Exemples of uranium and neutron activation logs treatment are presented [fr

  13. A link between prompt optical and prompt gamma-ray emission in gamma-ray bursts.

    Science.gov (United States)

    Vestrand, W T; Wozniak, P R; Wren, J A; Fenimore, E E; Sakamoto, T; White, R R; Casperson, D; Davis, H; Evans, S; Galassi, M; McGowan, K E; Schier, J A; Asa, J W; Barthelmy, S D; Cummings, J R; Gehrels, N; Hullinger, D; Krimm, H A; Markwardt, C B; McLean, K; Palmer, D; Parsons, A; Tueller, J

    2005-05-12

    The prompt optical emission that arrives with the gamma-rays from a cosmic gamma-ray burst (GRB) is a signature of the engine powering the burst, the properties of the ultra-relativistic ejecta of the explosion, and the ejecta's interactions with the surroundings. Until now, only GRB 990123 had been detected at optical wavelengths during the burst phase. Its prompt optical emission was variable and uncorrelated with the prompt gamma-ray emission, suggesting that the optical emission was generated by a reverse shock arising from the ejecta's collision with surrounding material. Here we report prompt optical emission from GRB 041219a. It is variable and correlated with the prompt gamma-rays, indicating a common origin for the optical light and the gamma-rays. Within the context of the standard fireball model of GRBs, we attribute this new optical component to internal shocks driven into the burst ejecta by variations of the inner engine. The correlated optical emission is a direct probe of the jet isolated from the medium. The timing of the uncorrelated optical emission is strongly dependent on the nature of the medium.

  14. Studies on gamma ray sensitivity in horsegram (Macrotyloma uniflorum Lam Verdc)

    International Nuclear Information System (INIS)

    Anitha, R.; Pradeep, R.; Prasannakumari, M.; Sudhagar, R.

    2017-01-01

    In the present study, it is aimed to generate viable mutants of Paiyur 2 having determinate growth habit, non shattering pods and reduced duration by 7-10 days. The reduced duration would help the variety suited to the area prone for terminal drought. The seed of the variety Paiyur 2 was treated with gamma ray doses ranging from 100 to 600 Gray (Gy). The seeds with 12 per cent moisture content were soaked for six hours in water, drained to the sufficient moisture, and mutated with gamma ray. The gamma chamber facility available in the Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural University (Model 1200) was made use of. One hundred seeds were mutated at each dose. The germination percentage, shoot and root length were documented at 14 days after sowing. Probit analysis was used to fix the LD50 value. The germination percentage varied between 0 to 20 per cent at higher concentrations. The lower germination was attributed to chromosomal abnormalities. From the study, it is determined that 300 Gy is the suitable dose at which maximum mutation occurs that offers scope for further exploitation

  15. Gamma and electron high dose dosimetry with rad-hard Si diodes

    International Nuclear Information System (INIS)

    Pascoalino, Kelly Cristina da Silva

    2014-01-01

    In this work the main dosimetric characteristics of rad-hard Float Zone (FZ) and magnetic Czochralski (MCz) diodes to electrons (1.5 MeV) and gamma ( 60 Co) radiation are evaluated. The dosimetric system proposed is based on electrical current measurements due to radiation interactions on the devices. The batch response uniformity was studied for the n-type FZ diodes irradiated with gamma rays. The coefficient of variation of the current measurement was about 1.25% at 5 kGy of accumulated dose. A sensitivity decrease with the increase of the accumulated dose (Total Ionizing Dose - TID) was observed for both FZ and MCz diodes. For gamma irradiation, these effect is more pronounced for n-type or smaller resistivity diodes. Two types of dosimetric probe were used on the electron irradiation procedures, one of them specially designed to avoid the deterioration of the electrical contacts and the diodes metallization. The sensitivity of the preirradiated FZ and MCz diodes fell about 10% and 40%, respectively, during electron irradiation at 1.25 MGy of accumulated dose. The effect of electron radiation damage on the electrical properties of the diodes was studied by the means of leakage current and capacitance measurements as a function of bias voltage. The leakage current increases with the accumulated dose but does not contributes significantly to the current signal, since the diodes are operated in photovoltaic mode, without bias voltage. For the MCz diode no change in the full depletion voltage was observed, which indicates its higher tolerance to radiation-induced damage, as expected. During electron irradiation the temperature increases and in order to determine its influence for the current signals, the leakage current values were extrapolated up to 35 °C. The contribution does not exceed 0.1% for FZ and MCz diodes. The effect of the radiation type, electrons or gamma rays, on the pre dose procedures was analyzed for the FZ n-type device and was observed that the

  16. Stellar Sources of Gamma-ray Bursts

    OpenAIRE

    Luchkov, B. I.

    2011-01-01

    Correlation analysis of Swift gamma-ray burst coordinates and nearby star locations (catalog Gliese) reveals 4 coincidences with good angular accuracy. The random probability is 4\\times 10^{-5}, so evidencing that coincident stars are indeed gamma-ray burst sources. Some additional search of stellar gamma-ray bursts is discussed.

  17. Gamma ray irradiation induced optical band gap variations in silica sol-gel doped sucrose

    International Nuclear Information System (INIS)

    Marzouki, F.; Farah, K.; Hamzaoui, A.H; Ben Ouada, H

    2015-01-01

    The silica xerogels doped sucrose was prepared via sol-gel process and exposed at room temperature to different doses of high energy ("6"0Co) gamma irradiation. Changes in the UV-visible and FTIR spectra of pristine and irradiated xerogels with varying of gamma doses rays show variation in the gap energy. It was found that energy gap of the investigated silica xerogels decreases with increasing the gamma irradiation doses. Thereby the irradiated samples reveal behaviour changes, from an insulator (Eg ∼5,8 eV) towards a semiconductor with (Eg ∼ 3.5 eV).

  18. Crystal growth and thermoluminescence response of NaZr2(PO4)3 at high gamma radiation doses

    International Nuclear Information System (INIS)

    Ordóñez-Regil, E.; Contreras-Ramírez, A.; Fernández-Valverde, S.M.; González-Martínez, P.R.; Carrasco-Ábrego, H.

    2013-01-01

    Graphical abstract: -- Highlights: •NaZr 2 (PO 4 ) 3 exposed to gamma doses of 10, 30 and 50 MGy. •Gamma radiation produced growth of the crystal size of the NZP. •Morphology changes were reversible by heating. •Linear relationship between the thermoluminescence and the applied gamma dose. •This property could be useful for high-level gamma dosimetry. -- Abstract: This work describes the synthesis and characterization of NaZr 2 (PO 4 ) 3 . The stability of this material under high doses of gamma radiation was investigated in the range of 10–50 MGy. Samples of unaltered and gamma irradiated NaZr 2 (PO 4 ) 3 were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and thermoluminescence. The results showed that while functional groups were not affected by the gamma irradiation, morphology changes were observed with increasing doses of gamma irradiation. The morphology of the non-irradiated compound is agglomerated flakes; however, irradiation at 10 MGy splits the flakes inducing the formation of well-defined cubes. Gamma irradiation induced the crystal size of the NaZr 2 (PO 4 ) 3 to grow. The heat treatment (973 K) of samples irradiated at 50 MGy resulted in the recovery of the original morphology. Furthermore, the thermoluminescence analysis of the irradiated compound is reported

  19. Measurements of the Cosmic Rays Dose at Different Altitudes of Iran

    International Nuclear Information System (INIS)

    Faghihi, R.; Mehdizadeh, S.; Jafarizadeh, M.; Sina, S.; Zehtabian, M.; Taheri, M.

    2012-01-01

    The amount of cosmic rays varies widely with the altitude, latitude and longitude in each region. In this study, the radiation doses due to the cosmic rays were estimated in two steps: in the first step, the neutron and gamma components of the radiation dose were measured for a roundtrip flight on 3 flight routes (Shiraz-Asaluye, Asaluye-Rasht and Shiraz-Mashhad) using a gamma-tracer photon detector and a Thyac 190 N, neutron detector. The minimum values of the measured gamma and neutron doses of 0.15 and 0.04μSv were measured on the Asaluyeh-Shiraz route at the lowest altitude of 19000 ft, while for Rasht-Asaluyeh route at an altitude of 35000 ft those values were found to be 2.52 and 1.09 mSv, respectively. In the second step, a number of air crew members were equipped with thermoluminescence dosimeters (TLD cards) for evaluating the gamma dose and polycarbonate dosimeters (SSNTD) for assessing the neutron dose for one year. The measured value of the annual effective dose received by the crew ranged between 0.5 mSv/y and 1.16 mSv/y, with an average of 0.9 mSv/y for the gamma component and between 0.37 mSv/y and 0.77 mSv/y with an average of 0.61 mSv/y for the neutron component. The results of this investigation are comparable with the investigations that have been conducted in other countries. For instance in UK, the reported annual effective dose of air crew is about 2 mSv, and in Canada, it is estimated to be between 1 to 5 mSv, depending on the flight situations (such as the latitude and longitude of the cities, the flight altitude, etc).

  20. Measurement of californium-252 gamma photons depth dose distribution in tissue equivalent material. Vol. 4

    Energy Technology Data Exchange (ETDEWEB)

    Fadel, M A; El-Fiki, M A; Eissa, H M; Abdel-Hafez, A; Naguib, S H [National Institute of Standards, Cairo (Egypt)

    1996-03-01

    Phantom of tissue equivalent material with and without bone was used measuring depth dose distribution of gamma-rays from californium-252 source. The source was positioned at center of perspex walled phantom. Depth dose measurements were recorded for X, Y and Z planes at different distances from source. TLD 700 was used for measuring the dose distribution. Results indicate that implantation of bone in tissue equivalent medium cause changes in the gamma depth dose distribution which varies according to variation in bone geometry. 9 figs.

  1. Radiation-induced reduction of diuron by gamma-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jibiao [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Zheng Zheng [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China)], E-mail: zzheng@nju.edu.cn; Zhao Tan [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Zhao Yongfu [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Institute of Atomic Energy, Jiangsu Academy of Agriculture Sciences, Nanjing 210014 (China); Wang Lianhong; Zhong Yun; Xu Yue [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China)

    2008-03-01

    Diuron degradation efficiencies and the proposed mechanism by gamma-ray irradiation were investigated. Several factors that might affect the degradation values were further examined. The UV absorbances at 200-400 nm and diuron concentration decreased with the increase of radiation dose. When diuron initial concentration was 18.5 mg L{sup -1} and 1.0 kGy was selected as the radiation dose, diuron removal value and loss of total organic carbon were 100 and 34.1%, respectively. However, the concentration of Cl{sup -} ion increased with the increase of radiation dose. The process could be depicted by first order reaction kinetics and the reaction was mainly caused by the reaction of diuron with {center_dot}OH and e{sub aq}{sup -}. The degradation efficiency decreased with the increase of initial concentration at the same radiation dose. H{sub 2}O{sub 2}, HCO{sub 3}{sup -}, NO{sub 3}{sup -}, NO{sub 2}{sup -}, CH{sub 3}OH and humic acid as additives reduced the degradation efficiency. Furthermore, the increase of NO{sub 3}{sup -}, NO{sub 2}{sup -}, CH{sub 3}OH and humic acid would result in the decrease of the degradation values. The pH value could affect the removal efficiency and the degradation process was enhanced in acid condition. The pH value became lower with increasing radiation dose after gamma-ray irradiation.

  2. Physical constraints on models of gamma-ray bursters

    International Nuclear Information System (INIS)

    Epstein, R.I.

    1985-01-01

    This report deals with the constraints that can be placed on models of gamma-ray burst sources based on only the well-established observational facts and physical principles. The premise is developed that the very hard x-ray and gamma-ray continua spectra are well-established aspects of gamma-ray bursts. Recent theoretical work on gamma-ray bursts are summarized with emphasis on the geometrical properties of the models. Constraints on the source models which are implied by the x-ray and gamma-ray spectra are described. The allowed ranges for the luminosity and characteristic dimension for gamma-ray burst sources are shown. Some of the deductions and inferences about the nature of the gamma-ray burst sources are summarized. 67 refs., 3 figs

  3. Microwave-gamma ray water in crude monitor

    International Nuclear Information System (INIS)

    Paap, H.J.

    1984-01-01

    A microwave-gamma ray water-in-crude monitoring system measures the percent quantity of fresh water or salt water in crude oil flowing in a pipe line. The system includes a measuring cell arranged with the pipe line so that the crude oil flows through the measuring cell. A microwave transmitter subsystem and a gamma ray source are arranged with the measuring cell so that microwave energy and gamma rays are transmitted through the measuring cell. A microwave receiving subsystem and a gamma ray detector provide signals corresponding to received microwave energy and to the received gamma rays, respectively. Apparatus connected to the microwave receiver and to the gamma ray detector provides an indication of the percentage of water in the crude oil

  4. Remote planetary geochemical exploration with the NEAR X-ray/gamma-ray spectrometer

    International Nuclear Information System (INIS)

    Trombka, J.I.; Boynton, W.V.; Brueckner, J.; Squyres, S.; Clark, P.E.; Starr, R.; Evans, L.G.; Floyd, S.R.; McClanahan, T.P.; Goldsten, J.; Mcnutt, R.; Schweitzer, J.S.

    1999-01-01

    The X-ray/gamma-ray spectrometer (XGRS) instrument onboard the Near Earth Asteroid Rendezvous (NEAR) spacecraft will map asteroid 433 Eros in the 0.2 keV to 10 MeV energy region. Measurements of the discrete line X-ray and gamma-ray emissions in this energy domain can be used to obtain both qualitative and quantitative elemental composition maps of the asteroid surface. The NEAR X-ray/gamma-ray spectrometer (XGRS) was turned on for the first time during the week of 7 April 1996. Rendezvous with Eros 433 is expected during December 1998. Observations of solar X-ray spectra during both quiescent and active periods have been made. A gamma-ray transient detection system has been implemented and about three gamma-ray transient events a week have been observed which are associated with either gamma-ray bursts or solar flares

  5. Sensitivity of Canola Seeds Associated Fungi to Gamma Rays During Storage

    International Nuclear Information System (INIS)

    Botros, H.W.

    2011-01-01

    The present study was carried out to investigate the possibility of using the gamma radiation to elongate the storage periods of canola seeds (Brassica naps L.). In this respect, canola seeds were irradiated at doses of 0.5, 1.5, 2.5, 3.5, 5.0 and 7.5 kGy gamma rays and stored at room temperature for periods 0, 3, 6, 9 and 12 months. The isolated fungi from non-irradiated post-harvest canola seeds included different species identified as Aspergillus flavus, A. niger, A. condidus, A. fumigatus, A. ochraceus, A. parasiticus, Fusarium oxysporium, F. moniliforme, Penicillium expansum, P. crysogenum, Alternaria brassicae, A. raphani and Trichoderma spp. It was noticed that the predominant species were A. ochraceus, A. flavus, A. niger and F. oxysporium at percentages 16.18, 14.73, 11.00 and 10.53%, respectively. The effective gamma irradiation on the predominant fungi (the sub-lethal dose) was 3.5 kGy for A. ochraceus and 5.0 kGy for F. oxysporium and F. moniliforme. Increasing the irradiated dose up to 7.5 kGy decreased significantly the growth of most isolated fungi. The data also showed that there was a decrease in the total fungal count in stored seeds under the effect of gamma rays for 12 months storage. Also, mycotoxins at the stored seeds were not detected after 12 months storage

  6. Study of hard X-ray dose enhancement effects for some kinds of semiconductor devices

    CERN Document Server

    Guo Hong Xia; Chen Yu Sheng; Zhou Hui; He Chao Hui; Xie Ya Ning; Huang Yu Ying; He Wei; Hu Tian Dou

    2002-01-01

    Experimental results of X-ray dose enhancement effects are given for CMOS4069 and floating gate ROMs irradiated in Beijing Synchrotron Radiation Facility and in cobalt source. Shift of threshold voltage vs. total dose for CMOS4069 and the errors vs. total dose for 28f256 and 29c256 have been tested on line and the equivalent relation of total dose damage under the same accumulated dose is provided comparing the response of devices irradiated by X-ray and gamma-ray source. These results can be provided for X-ray radiation hardening technology as an effective evaluation data

  7. Effects of gamma ray irradiation on early growth of soybean (Glycine mac (L). Merrill)

    International Nuclear Information System (INIS)

    Lilik Harsanti; Yulidar

    2015-01-01

    Increase my in domestic soybean production is one of the government's program to reduce dependence on imported soybeans and soybean efforts to achieve self-sufficiency in 2015. An experiment has been conducted to study the effects of gamma ray irradiation of of 60 Cobalt on early growth of soybean seed. Variety Denna 2 varieties have been irradiated by gamma rays with 0 Gy, 200 Gy, 300 Gy, 400 Gy doses, and then planted in green house on Ps Jumat PAIR-BATAN. Plant growth from each doses is proved to be varied. From germination viability on the third day, the highest percentage of seedling with leaves is on 100 Gy dose (73.75%), and 7, 14 and 21 day the lowest is on dose 400 Gy. (author)

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

    International Nuclear Information System (INIS)

    Al-Shmmary, A. J. M.; Al-Taweel, A. A.; Ahmed, R. F.

    2012-12-01

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

  9. Multifrequency Observations of Gamma-Ray Burst

    OpenAIRE

    Greiner, J.

    1995-01-01

    Neither a flaring nor a quiescent counterpart to a gamma-ray burst has yet been convincingly identified at any wavelength region. The present status of the search for counterparts of classical gamma-ray bursts is given. Particular emphasis is put on the search for flaring counterparts, i.e. emission during or shortly after the gamma-ray emission.

  10. Gamma-rays from deep inelastic collisions

    International Nuclear Information System (INIS)

    Stephens, F.S.

    1981-01-01

    My objective in this talk is to consider the question: 'What can be learned about deep inelastic collisions (DIC) from studying the associated gamma-rays'. First, I discuss the origin and nature of the gamma-rays from DIC, then the kinds of information gamma-ray spectra contain, and finally come to the combination of these two subjects. (orig./HSI)

  11. Soft x-ray emission from gamma-ray bursts observed with ginga

    International Nuclear Information System (INIS)

    Yoshida, Atsumasa; Murakami, Toshio; Itoh, Masayuki

    1989-01-01

    The soft X-ray emission of gamma-ray bursts below 10 keV provides information about size, location, and emission mechanism. The Gamma-ray Burst Detector (GBD) on board Ginga, which consists of a proportional counter and a scintillation detector, covers an energy range down to 1.5 keV with 63 cm 2 effective area. In several of the observed gamma-ray bursts, the intensity of the soft X-ray emission showed a longer decay time of 50 to 100s after the higher energy gamma-ray emission had ended. Although we cannot rule out other models, such as bremsstrahlung and thermal cyclotron types, due to poor statistics, the soft X-ray spectra are consistent with a blackbody of 1 to 2 keV in the late phase of the gamma-ray bursts. This enables us to estimate the size of the blackbody responsible for the X-ray emission. (author)

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

    International Nuclear Information System (INIS)

    Furtado Filho, Acacio A.M.; Gomes, Ailton de S.

    2011-01-01

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

  13. The high intensity {gamma}-ray source (HI{gamma}S) and recent results

    Energy Technology Data Exchange (ETDEWEB)

    Tonchev, A.P. [Duke University and TUNL, Triangle University Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 0308 (United States)]. E-mail: tonchev@tunl.duke.edu; Boswell, M. [University of North Carolina at Chapel Hill and TUNL, Chapel Hill, NC 27599 (United States); Howell, C.R. [Duke University and TUNL, Triangle University Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 0308 (United States); Karwowski, H.J. [University of North Carolina at Chapel Hill and TUNL, Chapel Hill, NC 27599 (United States); Kelley, J.H. [North Carolina State University and TUNL, Raleigh, NC 27695 (United States); Tornow, W. [Duke University and TUNL, Triangle University Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 0308 (United States); Wu, Y.K. [Duke University and Duke Free Electron Laser Laboratory, Durham, NC 27708-0319 (United States)

    2005-12-15

    The high intensity {gamma}-ray source (HI{gamma}S) utilizes intra-cavity backscattering of free electron laser photons from the Duke electron storage ring to produce a unique monoenergetic beam of high-flux {gamma}-rays with high polarization and selectable energy resolution. At present, {gamma}-ray beams with energies from 2 to 58 MeV are available with intensities as high as 10{sup 5}-5 x 10{sup 6} {gamma}/s, energy spreads of 3% or better, and nearly 100% linear polarization. The quality and intensity of the {gamma}-ray beams at HI{gamma}S are responsible for the unprecedented performance of this facility in a broad range of research programs in nuclear structure, nuclear astrophysics and nuclear applications. Recent results from excitation of isomeric states in ({gamma}, n) reactions and parity assignments of dipole states determined via the ({gamma}, {gamma}') reaction are presented.

  14. Gamma ray induced decomposition of lanthanide nitrates

    International Nuclear Information System (INIS)

    Joshi, N.G.; Garg, A.N.

    1992-01-01

    Gamma ray induced decomposition of the lanthanide nitrates, Ln(NO 3 ) 3 .xH 2 O where Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm and Yb has been studied at different absorbed doses up to 600 kGy. G(NO 2 - ) values depend on the absorbed dose and the nature of the outer cation. It has been observed that those lanthanides which exhibit variable valency (Ce and Eu) show lower G-values. An attempt has been made to correlate thermal and radiolytic decomposition processes. (author). 20 refs., 3 figs., 1 tab

  15. Gamma-ray Output Spectra from 239 Pu Fission

    International Nuclear Information System (INIS)

    Ullmann, John

    2015-01-01

    Gamma-ray multiplicities, individual gamma-ray energy spectra, and total gamma energy spectra following neutron-induced fission of 239 Pu were measured using the DANCE detector at Los Alamos. Corrections for detector response were made using a forward-modeling technique based on propagating sets of gamma rays generated from a paramaterized model through a GEANT model of the DANCE array and adjusting the parameters for best fit to the measured spectra. The results for the gamma-ray spectrum and multiplicity are in general agreement with previous results, but the measured total gamma-ray energy is about 10% higher. A dependence of the gamma-ray spectrum on the gamma-ray multplicity was also observed. Global model calculations of the multiplicity and gamma energy distributions are in good agreement with the data, but predict a slightly softer total-energy distribution

  16. X-ray and. gamma. -ray sources: a comparison of their characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Freund, A K [Institut Max von Laue - Paul Langevin, 38 - Grenoble (France)

    1979-11-01

    A comparison of the various source characteristics, in particular the available fluxes of radiation in the X-ray/..gamma..-ray region from (1) high power rotary anode X-ray generators, (2) radioactive ..gamma..-ray sources and (3) high energy electron storage rings is presented. Some of the specific characteristics and possible applications of synchrotron radiation as a source are discussed in detail, together with problems associated with the monochromatization of the continuous radiation in the X-ray/..gamma..-ray region. The new high energy machines PEP at Stanford, the 8 GeV storage ring CESR at Cornell and the PETRA storage ring in Hamburg, which will soon come into operation provide a spectrum of high intensity radiation reaching well above h..gamma..sub(photon)=100 keV. The possibilities of using ondulators (wigglers), and laser-electron scattering for constructing high repetition rate tunable ..gamma..-ray sources are also discussed. Finally the potentials of using the powerful spontaneous emission of ..gamma..-quanta by relativistic channeled particles are mentioned.

  17. Gamma-Ray Bursts

    Science.gov (United States)

    Pellizza, L. J.

    Gamma-ray bursts are the brightest transient sources in the gamma-ray sky. Since their discovery in the late 1960s, the investigation of the astrophysical sys- tems in which these phenomena take place, and the physical mechanisms that drive them, has become a vast and prolific area of modern astrophysics. In this work I will briefly describe the most relevant observations of these sources, and the models that describe their nature, emphasizing on the in- vestigations about the progenitor astrophysical systems. FULL TEXT IN SPANISH

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

    Science.gov (United States)

    Galper, A. M.; Adriani, O.; Aptekar, R. L.; Arkhangelskaja, I. V.; Arkhangelskiy, A. I.; Boezio, M.; Bonvicini, V.; Boyarchuk, K. A.; Fradkin, M. I.; Gusakov, Yu V.; hide

    2012-01-01

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

  19. Thermal neutron capture gamma-rays

    International Nuclear Information System (INIS)

    Tuli, J.K.

    1983-01-01

    The energy and intensity of gamma rays as seen in thermal neutron capture are presented. Only those (n,α), E = thermal, reactions for which the residual nucleus mass number is greater than or equal to 45 are included. These correspond to evaluations published in Nuclear Data Sheets. The publication source data are contained in the Evaluated Nuclear Structure Data File (ENSDF). The data presented here do not involve any additional evaluation. Appendix I lists all the residual nuclides for which the data are included here. Appendix II gives a cumulated index to A-chain evaluations including the year of publication. The capture gamma ray data are given in two tables - the Table 1 is the list of all gamma rays seen in (n,#betta#) reaction given in the order of increasing energy; the Table II lists the gamma rays according to the nuclide

  20. The Animated Gamma-ray Sky Revealed by the Fermi Gamma-ray Space Telescope

    International Nuclear Information System (INIS)

    Grenier, Isabelle

    2009-01-01

    The Fermi Gamma-ray Space Telescope has been observing the sky in gamma-rays since August 2008. In addition to breakthrough capabilities in energy coverage (20 MeV-300 GeV) and angular resolution, the wide field of view of the Large Area Telescope enables observations of 20% of the sky at any instant, and of the whole sky every three hours. It has revealed a very animated sky with bright gamma-ray bursts flashing and vanishing in minutes, powerful active galactic nuclei flaring over hours and days, many pulsars twinkling in the Milky Way, and X-ray binaries shimmering along their orbit. Most of these variable sources had not been seen by the Fermi predecessor, EGRET, and the wealth of new data already brings important clues to the origin of the high-energy emission and particles powered by the compact objects. The telescope also brings crisp images of the bright gamma-ray emission produced by cosmic-ray interactions in the interstellar medium, thus allowing to measure the cosmic nuclei and electron spectra across the Galaxy, to weigh interstellar clouds, in particular in the dark-gas phase. The telescope sensitivity at high energy will soon provide useful constraints on dark-matter annihilations in a variety of environments. I will review the current results and future prospects of the Fermi mission.

  1. Impact of intense x-ray pulses on a NaI(Tl)-based gamma camera

    NARCIS (Netherlands)

    Koppert, Wilco J C; van der Velden, Sandra; Steenbergen, J H Leo; de Jong, Hugo W A M

    2018-01-01

    INTRODUCTION: In SPECT/CT systems X-ray and -ray imaging is performed sequentially. Simultaneous acquisition may have advantages, for instance in interventional settings. However, this may expose a gamma camera to relatively high X-ray doses and deteriorate its functioning. We studied the NaI(Tl)

  2. Application of the alanine detector to gamma-ray, X-ray and fast neutron dosimetry

    International Nuclear Information System (INIS)

    Waligorski, M.P.R.; Hansen, J.W.; Byrski, E.

    1987-01-01

    A dosimeter based on alanine has been developed at the INP in Krakow and at Risoe National Laboratory. Due to its near tissue-equivalence and stability of signal, measured using ESR spectrometry at room temperature, this free-radical amino-acid dosimetric system is particularly suitable for measuring X-ray, gamma-ray and fast neutron doses in the range 10-10 5 Gy. The relative effectiveness (with respect to 60 Co γ-rays) of the alanine dosimeter to 250 kVp X-rays and to cyclotron-produced fast neutrons (mean neutron energy 5.6 MeV) is measured to be 0.76± 0.06 and 0.60±0.05, respectively. The suitability of the alanine dosimeter for intercomparison gamma-ray dosimetry is also shown. The estimated absolute difference between 60 Co dosimetry at Risoe National Laboratory and at the Centre of Oncology in Krakow is about 5%, somewhat more than the experimental uncertainty. These results are based on ESR measurements performed in Krakow on about 25% of the exposed detectors. 28 refs., 2 figs., 3 tabs. (author)

  3. An Imaging Camera for Biomedical Application Based on Compton Scattering of Gamma Rays

    OpenAIRE

    Fontana, Cristiano Lino

    2013-01-01

    In this thesis we present the R&D of a Compton Camera (CC) for small object imaging. The CC concept requires two detectors to obtain the incoming direction of the gamma ray. This approach, sometimes named ``Electronic Collimation,'' differs from the usual technique that employs collimators for physically selecting gamma-rays of a given direction. This solution offers the advantage of much greater sensitivity and hence smaller doses. We propose a novel design, which uses two simila...

  4. Sample analysis using gamma ray induced fluorescent X-ray emission

    Energy Technology Data Exchange (ETDEWEB)

    Sood, B S; Allawadhi, K L; Gandhi, R; Batra, O P; Singh, N [Punjabi Univ., Patiala (India). Nuclear Science Labs.

    1983-01-01

    A non-destructive method for the analysis of materials using gamma ray-induced fluorescent x-ray emission has been developed. In this method, special preparation of very thin samples in which the absorption of the incident gamma rays and the emitted fluorescent x-rays is negligible, is not needed, and the absorption correction is determined experimentally. A suitable choice of the incident gamma ray energies is made to minimise enhancement effects through selective photoionization of the elements in the sample. The method is applied to the analysis of a typical sample of the soldering material using 279 keV and 59.5 keV gamma rays from /sup 203/Hg and /sup 241/Am radioactive sources respectively. The results of the analysis are found to agree well with those obtained from the chemical analysis.

  5. Protective effects of vitamin C against gamma-ray induced wholly damage and genetic damage

    International Nuclear Information System (INIS)

    Fu Chunling; Jiang Weiwei; Zhang Ping; Chen Xiang; Zhu Shengtao

    2000-01-01

    Objective: Protective effects of supplemental vitamin C against 60 Co-gamma-ray induced wholly damage and genetic damage was investigated in mice. Method: Mice were divided into normal control group, irradiation control group and vitamin C experimental group 1,2,3 (which were orally given vitamin C 15, 30, 45 mg/kg.bw for 10 successive days respectively prior to gamma-ray irradiation). Micronuclei in the bone marrow polychromatophilic erythrocytes in each group of mice were examined and the 30 day survival rate of mice following whole-body 5.0 Gy γ irradiation were also determined. Results: Supplemental vitamin C prior to gamma-rays irradiation can significantly decrease bone marrow PECMN rate of mice and increase 30 day survival rate and prolong average survival time. The protection factor is 2.09. Conclusion: Vitamin C has potent protective effects against gamma irradiation induced damage in mice. In certain dose range, vitamin C can absolutely suppress the gamma-rays induced genetic damage in vivo

  6. GammaLog Playback 1.0 - mobile gamma ray spectrometry software

    International Nuclear Information System (INIS)

    Watson, R.J.; Smethurst, M.A.

    2011-01-01

    The Geological Survey of Norway (NGU) operates a mobile gamma ray spectrometer system which can be used in nuclear emergency situations to determine the location and type of orphan sources, or the extent and type of fallout contamination. The system consists of a 20 litre (16 litre downward and 4 litre upward looking) RSX-5 NaI detector and spectrometer, and can be mounted in fixed wing aircraft, helicopters, or vans/cars as appropriate. NGU has developed its own data acquisition and analysis software for this system. GammaLog (Smethurst 2005) controls the acquisition, display, and storage of data from the spectrometer, and performs real-time data analysis including estimation of dose rates and fallout concentrations, and separation of geological and anthropogenic components of the signal. The latter is particularly important where the geological radioisotope signal varies strongly from one place to another, and makes it easier to locate and identify anthropogenic sources which might otherwise be difficult to separate from the geological background signal. A modified version of GammaLog has been developed, GammaLog Playback, which allows the replay of previously acquired GammaLog datasets, while performing similar processing and display as the GammaLog acquisition software. This allows datasets to be reviewed and compared in the field or during post-survey analysis to help plan subsequent measurement strategies.(Au)

  7. ICIT contribution to JET gamma-ray diagnostics enhancement

    International Nuclear Information System (INIS)

    Soare, S.; Curuia, M.; Zoita, V.

    2010-01-01

    Full text: Gamma-ray emission of tokamak plasmas is the result of the interaction of fast ions (fusion reaction products, including alpha particles, NBI ions, ICRH-accelerated ions) with main plasma impurities (e.g., carbon, beryllium). Gamma-ray diagnostics involve both gamma-ray imaging (cameras) and gamma-ray spectrometry (spectrometers). For the JET tokamak, gamma-ray diagnostics have been used to provide information on the characteristics of the fast ion population in plasmas. Two gamma-ray diagnostics enhancements project have been launched by JET and the MEdC/EURATOM Association has agreed to lead both of them with ICIT as projects leader. (authors)

  8. Gamma-ray burst observations: the present situation

    International Nuclear Information System (INIS)

    Vedrenne, G.

    1984-01-01

    Recent results in gamma ray burst investigations concerning the spectral variability on a short time scale, precise locations, and the discovery of optical flashes in gamma ray burst positions on archival plates are presented. The implications of optical and X-ray observations of gamma ray burst error boxes are also discussed. 72 references

  9. Neutron detection in a high gamma-ray background with EJ-301 and EJ-309 liquid scintillators

    International Nuclear Information System (INIS)

    Stevanato, L.; Cester, D.; Nebbia, G.; Viesti, G.

    2012-01-01

    Using a fast digitizer, the neutron–gamma discrimination capability of the new liquid scintillator EJ-309 is compared with that obtained using standard EJ-301. Moreover the capability of both the scintillation detectors to identify a weak neutron source in a high gamma-ray background is demonstrated. The probability of neutron detection is PD=95% at 95% confidence level for a gamma-ray background corresponding to a dose rate of 100 μSv/h.

  10. Gamma ray irradiation to semi-purified diet

    International Nuclear Information System (INIS)

    Takigawa, Akihiro; Danbara, Hiroshi; Ohyama, Yoshinobu

    1976-01-01

    Semi-purified diet containing 10% soybean oil was irradiated with gamma rays at levels of 0.6, 3 and 6 Mrad and was fed to chicks. Crude fat contents of the diets decreased and a considerable amount of peroxide was formed with high doses of irradiation. Feed consumption and feed efficiency of the highly irradiated diets were less than those of control. Metabolizable energy and digestibility of the diets, especially of fat, were decreased with the irradiation. The chicks fed with irradiated diets showed marked dilatation of the small intestine and the liver, and their erythrocytes were more fragile than those of control. The same phenomena were found with the chicks fed the diet containing the oil highly oxidized by autoxidation. Irradiation of the diet excluding oil showed little effect on the growth of chicks. It was considered that these phenomena were caused by the peroxide or other oxidation products of fat which were formed with gamma ray irradiation. (auth.)

  11. Mapping the terrestrial air-absorbed gamma dose rate based on the data of airborne gamma-ray spectrometry in southern cities of China

    International Nuclear Information System (INIS)

    Xiong Shengqing; Fan Zhengguo; Wu Qifan; Wan Jianhua; Wang Nanping; Chu Xingming; Pei Shaoying; Zeng Lihui

    2012-01-01

    An environmental radioactivity survey by Airborne Gamma-ray Spectrometry (AGS) on a large scale was undertaken in Zhuhai Zone (ZZ) and Shenzhen Zone (SZ), which include major cities in southern China, covering areas of 3800 km 2 and 4660 km 2 , respectively. The estimated dose rates by AGS have been compared with observed results by ionization chamber and portable dosemeter. Maps of the terrestrial dose rate at 1m above ground level have been calculated based on the data of AGS. The mean dose rates are 84.37 ± 51.69 and 82.10 ± 32.98 nGy/h in ZZ and SZ, and the maximum rates are 343.11 and 368.36 nGy/h, respectively. Dose rates in some places are above 180 nGy/h; the areas covered where 149 km 2 in ZZ and 43 km 2 in SZ. The dominant geological conditions that evidently contribute to the radioactive anomalies are outcrops of Middle and Late Jurassic and Cretaceous biotitic-granite. The growth of industrialization and urbanization has dramatically altered radiation background. Stone mining results in the increase of radiation levels with maximum dose rates approaching 368.36 nGy/h in an open pit. The investigation results provide valuable background data and give a good example for mapping nationwide natural radiation terrestrial dose rates in China by AGS. (author)

  12. Found: A Galaxy's Missing Gamma Rays

    Science.gov (United States)

    Kohler, Susanna

    2016-04-01

    Recent reanalysis of data from the Fermi Gamma-ray Space Telescope has resulted in the first detection of high-energy gamma rays emitted from a nearby galaxy. This discovery reveals more about how supernovae interact with their environments.Colliding Supernova RemnantAfter a stellar explosion, the supernovas ejecta expand, eventually encountering the ambient interstellar medium. According to models, this generates a strong shock, and a fraction of the kinetic energy of the ejecta is transferred into cosmic rays high-energy radiation composed primarily of protons and atomic nuclei. Much is still unknown about this process, however. One open question is: what fraction of the supernovas explosion power goes into accelerating these cosmic rays?In theory, one way to answer this is by looking for gamma rays. In a starburst galaxy, the collision of the supernova-accelerated cosmic rays with the dense interstellar medium is predicted to produce high-energy gamma rays. That radiation should then escape the galaxy and be visible to us.Pass 8 to the RescueObservational tests of this model, however, have beenstumped by Arp 220. This nearby ultraluminous infrared galaxy is the product of a galaxy merger ~700 million years ago that fueled a frenzy of starbirth. Due to its dusty interior and extreme levels of star formation, Arp 220 has long been predicted to emit the gamma rays produced by supernova-accelerated cosmic rays. But though weve looked, gamma-ray emission has never been detected from this galaxy until now.In a recent study, a team of scientists led by Fang-Kun Peng (Nanjing University) reprocessed 7.5 years of Fermi observations using the new Pass 8 analysis software. The resulting increase in resolution revealed the first detection of GeV emission from Arp 220!Acceleration EfficiencyGamma-ray luminosity vs. total infrared luminosity for LAT-detected star-forming galaxies and Seyferts. Arp 220s luminosities are consistent with the scaling relation. [Peng et al. 2016

  13. Effect of gamma-ray on olive fruits quality, enzyme activities and issued oil

    International Nuclear Information System (INIS)

    Mejri, Sonia

    2007-01-01

    The results described in the present work concern the study of changes in gamma ray irradiated olive fruit (Tunisian variety: C hemlali ) quality along the storage time processing and the quality of olive oil issued. The study focused on the changes related to the microbiological, physico-chemical properties, as well as pectinase activities in olive after irradiation. We also have been interested in the final product quality after oil extraction. The results of non irradiated olives were presented for comparative purposes. Mature olive fruits were treated with 0.5, 1 and 1.5 kGy gamma ray radiation. Olive fruits were then stored for one month. Irradiation at 1.5 kGy allows the almost total destruction of the total aerobic germs, yeasts and moulds. Concerning physico-chemical parameters, the increase of the dose level generated an improvement in water retention capacity and decreased the rate of polysaccharides hydrolyzes olives. Moreover, the irradiation dose of 0.5 kGy induced the increase in pectinase activities thanks to the improvement of the protein extraction yield. The gamma ray irradiation of olive fruit seems to not decrease olive oil oxidative stability in the studied samples. Finally, gamma ray radiation was able to improve the yield of extraction of the oil and insaponifiable fraction as polyphenols and beta carotenes. (Author)

  14. Enhancement of gamma-ray radiolysis of carbon dioxide with the assistance of solid materials

    International Nuclear Information System (INIS)

    Watanabe, D.; Allen, C.; Yoshida, T.; Tanabe, T.

    2007-01-01

    This work is devoted to enhance gamma-ray radiolysis of CO 2 with the assistance of coexisting metal materials. It is found that lower energy electrons which are generated through interactions of γ-photons with the coexisting metal materials and ejected to CO 2 gas actually enhance decomposition of CO 2 to produce CO. The increment of CO production agrees well with the increment of the deposited energy in CO 2 , given by the lower energy electrons emitted from the materials, which is calculated by a numerical simulations code MCNP. It is also suggested that the volumetric decomposition of CO 2 dominates the decomposition at the material's surface. (author)

  15. ZZ DOSDAT-2, Gamma and Electron Dose Conversion Factor Data Library for Body Organs

    International Nuclear Information System (INIS)

    1983-01-01

    1 - Description of problem or function: Format: DOSDAT-R; Nuclides: gamma-ray and electron dose rates for whole-body and for various body organs (24) for air and water immersion and from ground-surface sources (approximately 500 radioactive nuclides). Origin: DLC-80/DRALIST library of radioactive decay data. The data are used to estimate the gamma-ray and electron dose rates for whole-body and for various body organs (24) for air and water immersion and from ground-surface sources. The data are given for approximately 500 radioactive nuclides. 2 - Method of solution: The data were computed by the CCC-400 DOSAFACTER II code from the DLC-80/DRALIST library of radioactive decay data for approximately 500 nuclides

  16. Displacement damage caused by gamma-rays and neutrons on Au and Se.

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, Barney Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-11-01

    This report documents theoretical calculations of displacement damage produced by gamma rays and neutrons on various materials. The average energy of the gamma rays was 1.24 MeV and 1.0 MeV for the neutrons. The fluence of the gamma rays was 1.2e14 γ/cm2 , for the neutrons it was 1.0e12 n/cm2. The initial materials of interest were Au and Se. The total doses of the gamma ray exposures were in the 100 kRad range for both elements. An equivalent electron fluence was approximated to be the same as the gamma ray fluence over one gamma ray attenuation length in both materials and at the same 1.24 MeV energy. The maximum recoil energy of the Au and Se for these electrons was calculated relativisticaly to be 29 and 72 eV respectively. The relativisitic McKinley and Feshbach theory for the atomic recoil cross sections produced by the electrons were in the 10s of mbarn range and an upper limit for the concentration of Frenkel pairs for the gamma ray exposures for both elements was in the ppb range. The Robinson Energy Partioning Theory for non-ionizing energy loss (NIEL) of ions in solids was used to calculate the concentration of Frenkel pairs produced by the 1 MeV neutrons, and this concentration was also in the ppb range for both Au and Se. Low damage levels like this can have effects on minority carrier recombination in semiconductors, but are not expected to have any effect on metals like Au, or metalloids such as Se.

  17. Estimate on external effective doses received by the Iranian population from environmental gamma radiation sources

    Energy Technology Data Exchange (ETDEWEB)

    Roozitalab, J.; Reza deevband, M.; Rastkhah, N. [National Radiation Protection Dept. Atomic Energy Organization (Iran, Islamic Republic of); Sohrabi, M. [Intenatinal atomic Energy Agency, Vienna (Austria)

    2006-07-01

    Concentration of natural radioactive materials, especially available U 238, Ra 226, Th 232, and K 40 in construction materials and soil, as well as absorb dose from cosmic rays, is the most important source of the people for effective doses from the environment radiation. In order to evaluate external effective dose, it has been carried out more than 1000 measurements in 36 cities by sensitive dosimeters to environmental gamma radiation for indoor and outdoor conditions in residential areas; which its results show that range of gamma exposure for inside of buildings in Iran is 8.7-20.5 {mu}R/h, and outdoor environments of different cities is 7.9-20.6 {mu}R/h, which their mean value are 14.33 and 12.62 {mu}R/h respectively. Meanwhile, it has been estimated that beam-absorbing ratio between indoor and outdoor in measured environments is 1.55, except contribution of cosmic rays. This studies show that average effective dose for each Iranian person from environmental gamma is 96.9 n Sv/h, and annually effective dose for every person is 0.848 mSv. (authors)

  18. Estimate on external effective doses received by the Iranian population from environmental gamma radiation sources

    International Nuclear Information System (INIS)

    Roozitalab, J.; Reza deevband, M.; Rastkhah, N.; Sohrabi, M.

    2006-01-01

    Concentration of natural radioactive materials, especially available U 238, Ra 226, Th 232, and K 40 in construction materials and soil, as well as absorb dose from cosmic rays, is the most important source of the people for effective doses from the environment radiation. In order to evaluate external effective dose, it has been carried out more than 1000 measurements in 36 cities by sensitive dosimeters to environmental gamma radiation for indoor and outdoor conditions in residential areas; which its results show that range of gamma exposure for inside of buildings in Iran is 8.7-20.5 μR/h, and outdoor environments of different cities is 7.9-20.6 μR/h, which their mean value are 14.33 and 12.62 μR/h respectively. Meanwhile, it has been estimated that beam-absorbing ratio between indoor and outdoor in measured environments is 1.55, except contribution of cosmic rays. This studies show that average effective dose for each Iranian person from environmental gamma is 96.9 n Sv/h, and annually effective dose for every person is 0.848 mSv. (authors)

  19. Multiwavelength Study of Gamma-Ray Bright Blazars

    Science.gov (United States)

    Morozova, Daria; Larionov, V. M.; Hagen-Thorn, V. A.; Jorstad, S. G.; Marscher, A. P.; Troitskii, I. S.

    2011-01-01

    We investigate total intensity radio images of 6 gamma-ray bright blazars (BL Lac, 3C 279, 3C 273, W Com, PKS 1510-089, and 3C 66A) and their optical and gamma-ray light curves to study connections between gamma-ray and optical brightness variations and changes in the parsec-scale radio structure. We use high-resolution maps obtained by the BU group at 43 GHz with the VLBA, optical light curves constructed by the St.Petersburg State U. (Russia) team using measurements with the 0.4 m telescope of St.Petersburg State U. (LX200) and the 0.7 m telescope of the Crimean Astrophysical Observatory (AZT-8), and gamma-ray light curves, which we have constructed with data provided by the Fermi Large Area Telescope. Over the period from August 2008 to November 2009, superluminal motion is found in all 6 objects with apparent speed ranging from 2c to 40c. The blazars with faster apparent speeds, 3C 273, 3C 279, PKS 1510-089, and 3C 66A, exhibit stronger variability of the gamma-ray emission. There is a tendency for sources with sharply peaked gamma-ray flares to have faster jet speed than sources with gamma-ray light curves with no sharp peaks. Gamma-ray light curves with sharply peaked gamma-ray flares possess a stronger gamma-ray/optical correlations. The research at St.Petersburg State U. was funded by the Minister of Education and Science of the Russian Federation (state contract N#P123). The research at BU was funded in part by NASA Fermi Guest Investigator grant NNX08AV65G and by NSF grant AST-0907893. The VLBA is an instrument of the National Radio Astronomy Observatory, a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

  20. Delayed Fission Product Gamma-Ray Transmission Through Low Enriched UO2 Fuel Pin Lattices in Air

    Energy Technology Data Exchange (ETDEWEB)

    Trumbull, TH [Rensselaer Polytechnic Inst., Troy, NY (United States)

    2004-10-18

    The transmission of delayed fission-product gamma rays through various arrangements of low-enriched UO2 fuel pin lattices in an air medium was studied. Experimental measurements, point-kernel and Monte Carlo photon transport calculations were performed to demonstrate the shielding effect of ordered lattices of fuel pins on the resulting gamma-ray dose to a detector outside the lattice. The variation of the gamma-ray dose on the outside of the lattice as a function of radial position, the so-called “channeling” effect, was analyzed. Techniques for performing experimental measurements and data reduction at Rensselaer Polytechnic Institute’s Reactor Critical Facility (RCF) were derived. An experimental apparatus was constructed to hold the arrangements of fuel pins for the measurements. A gamma-ray spectroscopy system consisting of a sodium-iodide scintillation detector was used to collect data. Measurements were made with and without a collimator installed. A point-kernel transport code was developed to map the radial dependence of the gamma-ray flux. Input files for the Monte Carlo code, MCNP, were also developed to accurately model the experimental measurements. The results of the calculations were compared to the experimental measurements. In order to determine the delayed fission-product gamma-ray source for the calculations, a technique was developed using a previously written code, DELBG and the reactor state-point data obtained during the experimental measurements. Calculations were performed demonstrating the effects of material homogenization on the gamma-ray transmission through the fuel pin lattice.Homogeneous and heterogeneous calculations were performed for all RCF fuel pin lattices as well as for a typical commercial pressurized water reactor fuel bundle. The results of the study demonstrated the effectiveness of the experimental measurements to isolate the channeling effect of delayed fission-product gamma-rays through lattices of RCF fuel pins

  1. Timing of Pulsed Prompt Gamma Rays for Background Discrimination

    International Nuclear Information System (INIS)

    Hueso-Gonzalez, F.; Golnik, C.; Berthel, M.; Dreyer, A.; Kormoll, T.; Rohling, H.; Pausch, G.; Enghardt, W.; Fiedler, F.; Heidel, K.; Schoene, S.; Schwengner, R.; Wagner, A.

    2013-06-01

    In the context of particle therapy, particle range verification is a major challenge for the quality assurance of the treatment. One approach is the measurement of the prompt gamma rays resulting from the tissue irradiation. A Compton camera based on several planes of position sensitive gamma ray detectors, together with an imaging algorithm, is expected to reconstruct the prompt gamma ray emission density profile, which is correlated with the dose distribution. At Helmholtz- Zentrum Dresden-Rossendorf (HZDR) and OncoRay, a camera prototype has been developed consisting of two scatter planes (CdZnTe cross strip detectors) and an absorber plane (Lu 2 SiO 5 block detector). The data acquisition is based on VME electronics and handled by software developed on the ROOT platform. The prototype was tested at the linear electron accelerator ELBE at HZDR, which was set up to produce bunched bremsstrahlung photons. Their spectrum has similarities with the one expected from prompt gamma rays in the clinical case, and these are also bunched with the accelerator frequency. The time correlation between the pulsed prompt photons and the measured signals was used for background discrimination, achieving a time resolution of 3 ns (2 ns) FWHM for the CZT (LSO) detector. A time-walk correction was applied for the LSO detector and improved its resolution to 1 ns. In conclusion, the detectors are suitable for time-resolved background discrimination in pulsed clinical particle accelerators. Ongoing tasks are the test of the imaging algorithms and the quantitative comparison with simulations. Further experiments will be performed at proton accelerators. (authors)

  2. Induction of cell death in the testis of Heteracris littoralis by gamma rays

    International Nuclear Information System (INIS)

    Al-Taweel, A.A.; Shawkit, M.A.

    1983-01-01

    Cell killing by gamma rays was studied in Heteracris littoralis. Primary spermatocytes, which are encysted and have cytoplasmic connection, show unusual dose-response kinetics with no shoulder at low doses. Also, the spermatocytes do not die independently but in groups, usually with whole cysts degenerating synchronously. (author)

  3. Gamma radiation influence on Cladonia substellata (lichen) and its effects on limestone rocks

    International Nuclear Information System (INIS)

    Silva, Helena P. de B.; Colaco, Waldeciro; Pereira, Eugenia C.; Silva, Nicacio H. da

    2009-01-01

    The lichens play an important role in decomposition of the rocky substrate, through the chemical weathering of their substances. This work aimed to determine the influence of gamma Ray on usnic acid production of Cladonia substellata and the influence of chelates formation in limestone rocks. Samples with 2.5 g of C. substellata were packed on paper envelopes for irradiation submission to gamma on a Co-60 source. They received 10 different doses: 5, 7, 10, 15, 20, 30, 40, 50, 60 and 80 Gy. Lichen irradiation was conducted on the gamma irradiator (Co-60), and packed over powdered limestone. Lichen samples were analyzed by High Performance Liquid Chromatography (HPLC) and rocky samples by X-Ray Diffractometry. The X-ray diffractogram obtained from the analysis of limestone not subjected to the action of lichen - control sample was compared with limestone subjected to C. substellata irradiated at doses 10, 30 and 80Gy. Increased production of the usnic acid and changes on the rocky samples were noted. We realized that C. substellata increments the usnic acid biosynthesis as the gamma radiation dose is increased, but there is a limit to it. The chelating effect of the usnic acid on limestone was proportional to the produced amount of the substance, which could be extrapolated to natural conditions, where excessive radiation may influence pedogenesis and ecological succession. (author)

  4. Gamma-Ray Emission from Galaxy Clusters : DARK MATTER AND COSMIC-RAYS

    Science.gov (United States)

    Pinzke, Anders

    The quest for the first detection of a galaxy cluster in the high energy gamma-ray regime is ongoing, and even though clusters are observed in several other wave-bands, there is still no firm detection in gamma-rays. To complement the observational efforts we estimate the gamma-ray contributions from both annihilating dark matter and cosmic-ray (CR) proton as well as CR electron induced emission. Using high-resolution simulations of galaxy clusters, we find a universal concave shaped CR proton spectrum independent of the simulated galaxy cluster. Specifically, the gamma-ray spectra from decaying neutral pions, which are produced by CR protons, dominate the cluster emission. Furthermore, based on our derived flux and luminosity functions, we identify the galaxy clusters with the brightest galaxy clusters in gamma-rays. While this emission is challenging to detect using the Fermi satellite, major observations with Cherenkov telescopes in the near future may put important constraints on the CR physics in clusters. To extend these predictions, we use a dark matter model that fits the recent electron and positron data from Fermi, PAMELA, and H.E.S.S. with remarkable precision, and make predictions about the expected gamma-ray flux from nearby clusters. In order to remain consistent with the EGRET upper limit on the gamma-ray emission from Virgo, we constrain the minimum mass of substructures for cold dark matter halos. In addition, we find comparable levels of gamma-ray emission from CR interactions and dark matter annihilations without Sommerfeld enhancement.

  5. Effect of gamma ray irradiation on seed germination of Ardisia crenata

    International Nuclear Information System (INIS)

    Huang Donghua; Xu Hong; Huang Yanping; Song Xiaomin

    2011-01-01

    The seeds of Ardisia crenata were used as experimental material and treated with gamma ray under the irradiative doses ranging from 50 to 500 Gy. The results showed that the seed germination rates were not affected under the irradiative dose of 150 Gy and below. The germination potentiality turned to reduce while the irradiative dose was higher than 250 Gy. And in the range of 300 to 500 Gy the germination rates were decreased with the increase of the irradiative dose. (authors)

  6. Neutron detection gamma ray sensitivity criteria

    International Nuclear Information System (INIS)

    Kouzes, Richard T.; Ely, James H.; Lintereur, Azaree T.; Mace, Emily K.; Stephens, Daniel L.; Woodring, Mitchell L.

    2011-01-01

    The shortage of 3 He has triggered the search for effective alternative neutron detection technologies for national security and safeguards applications. Any new detection technology must satisfy two basic criteria: (1) it must meet a neutron detection efficiency requirement, and (2) it must be insensitive to gamma-ray interference at a prescribed level, while still meeting the neutron detection requirement. It is the purpose of this paper to define measureable gamma ray sensitivity criteria for neutron detectors. Quantitative requirements are specified for: intrinsic gamma ray detection efficiency and gamma ray absolute rejection. The gamma absolute rejection ratio for neutrons (GARRn) is defined, and it is proposed that the requirement for neutron detection be 0.9 3 He based neutron detector is provided showing that this technology can meet the stated requirements. Results from tests of some alternative technologies are also reported.

  7. Dose-rate effects and chronological changes of chromosome aberration rates in spleen cells from mice that are chronically exposed to gamma-ray at low dose rates

    International Nuclear Information System (INIS)

    Tanaka, Kimio; Kohda, Atsushi; Ichinohe, Kazuaki; Matsumoto, Tsuneya; Oghiso, Yoichi

    2006-01-01

    Dose-rate effects have not been examined in the low dose-rate regions of less than 60-600 mGy/h. Mice were chronically exposed to gamma-ray at 20 mGy/day (approximately 1 mGy/h) up to 700 days and at 1 mGy/day (approximately 0.05 mGy/h) for 500 days under SPF conditions. Chronological changes of chromosome aberration rates in spleen cells were observed along with accumulated doses at both low dose-rates. Unstable aberrations increased in a biphasic manner within 0-2 Gy and 4-14 Gy in 20 mGy/day irradiation. They slightly increased up to 0.5 Gy in 1 mGy/day irradiation. Chromosome aberration rates at 20 mGy/day and 1 mGy/day were compared at the same total doses of 0.5 Gy and 0.25 Gy. They were 2.0 vs. 0.53, and 1.0 vs. 0.47 respectively. Thus, dose-rate effects were observed in these low dose-rate regions. (author)

  8. Delayed Fission Gamma-ray Characteristics of Th-232 U-233 U-235 U-238 and Pu-239

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Taylor [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Parma, Edward J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    Delayed fission gamma-rays play an important role in determining the time dependent ioniz- ing dose for experiments in the central irradiation cavity of the Annular Core Research Reactor (ACRR). Delayed gamma-rays are produced from both fission product decay and from acti- vation of materials in the core, such as cladding and support structures. Knowing both the delayed gamma-ray emission rate and the time-dependent gamma-ray energy spectrum is nec- essary in order to properly determine the dose contributions from delayed fission gamma-rays. This information is especially important when attempting to deconvolute the time-dependent neutron, prompt gamma-ray, and delayed gamma-ray contribution to the response of a diamond photo-conducting diode (PCD) or fission chamber in time frames of milliseconds to seconds following a reactor pulse. This work focused on investigating delayed gamma-ray character- istics produced from fission products from thermal, fast, and high energy fission of Th-232, U-233, U-235, U-238, and Pu-239. This work uses a modified version of CINDER2008, a transmutation code developed at Los Alamos National Laboratory, to model time and energy dependent photon characteristics due to fission. This modified code adds the capability to track photon-induced transmutations, photo-fission, and the subsequent radiation caused by fission products due to photo-fission. The data is compared against previous work done with SNL- modified CINDER2008 [ 1 ] and experimental data [ 2 , 3 ] and other published literature, includ- ing ENDF/B-VII.1 [ 4 ]. The ability to produce a high-fidelity (7,428 group) energy-dependent photon fluence at various times post-fission can improve the delayed photon characterization for radiation effects tests at research reactors, as well as other applications.

  9. Evaluation of gamma-ray intensities

    International Nuclear Information System (INIS)

    Yoshizawa, Yasukazu; Inoue, Hikaru; Hoshi, Masaharu; Shizuma, Kiyoshi; Iwata, Yosei.

    1980-04-01

    Relative intensities and intensities per decay of gamma rays were evaluated for 16 nuclides, 22 Na, 24 Na, 46 Sc, 54 Mn, 60 Co, 85 Sr, 88 Y, 95 Nb, sup(108m)Ag, 134 Cs, 133 Ba, 139 Ce, sup(180m)Hf, 198 Au, 203 Hg and 207 Bi. For most of these nuclides disintegration rates can be determined by means of β-γ or X-γ coincidence method. Since decay schemes of these nuclides are established, intensities per decay of strong gamma rays were accurately evaluated by using weak beta-ray branching ratios, relative gamma-ray intensities and internal conversion coefficients. Half-lives of the nuclides were also evaluated. Use of the nuclides, therefore, are recommended for precision intensity calibration of the detectors. (author)

  10. Local gamma ray events as tests of the antimatter theory of gamma ray bursts

    International Nuclear Information System (INIS)

    Sofia, S.; Wilson, R.E.

    1976-01-01

    Nearby examples of the antimatter 'chunks' postulated by Sofia and Van Horn to explain the cosmic gamma ray bursts may produce detectable gamma ray events when struck by solar system meteoroids. These events would have a much shorter time scale and higher energy spectrum than the bursts already observed. In order to have a reasonably high event rate, the local meteoroid population must extend to a distance from the Sun of the order of 0.1 pc, but the required distance could become much lower if the instrumental threshold is improved. The expected gamma ray flux for interaction of the antimatter bodies with the solar wind is also examined, and found to be far below present instrumental capabilities. (Auth.)

  11. Mutation studies in gamma-ray treated peas

    Energy Technology Data Exchange (ETDEWEB)

    Narsinghani, V G; Kumar, S [Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur (India). Dept. of Plant Breeding

    1976-01-01

    Pea Seeds (Pisum Sativum L. 2n=14) irradiated with four doses of gamma rays viz, 10, 15, 20 and 25 kR revealed a reduction in seedling height, survival percentage, pods and seed yield and pollen fertility during X/sub 1/ and X/sub 2/ generations. Chlorophyll and leaf mutations were noted. The mitotic cells indicated chromosomal aberrations which were dose dependent. In meiosis, translocated rings and chains of 4,6 and 8 chromosomes; paracentric and pericentric inversions, fragments, laggards and unequal distribution of chromosomes were observed. Besides, the frequency of aberrations were lower during X/sub 2/ as compared to X/sub 1/.

  12. Gamma Ray Bursts

    Science.gov (United States)

    Gehrels, Neil; Meszaros, Peter

    2012-01-01

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

  13. ESR Study of the polyvinyl alcohol gamma-ray induced free-radicals

    International Nuclear Information System (INIS)

    Rosas S, E.

    1994-01-01

    This work reports the findings of the molecular weight effect on the electron spin resonance saturation curve of the gamma-ray irradiated polyvinyl alcohol, G-RIPVA. It has been noted that Pva of a lower molecular weight, between 13,000-23,000, show some noticeable differences in the electron spin resonance, ESR, response as a function of the gamma-ray dose in the 1-100 k Gy range than the one reported in the literature with molecular weight of 108,000. Results show a linear response in the log-log plot of the dose vs ESR signal intensity for samples based on G-RIPVA of the lower molecular weight as contrasted with the non-linear ESR response of G-RIPVA of higher molecular weight in the above named dose range. Such a result has been assumed to arise from the shorter molecular chains for the case of the lower molecular weight samples making this to increase the production of Pva free radicals with respect to the absorbed studied doses. Also, a discussion on the nature and stability of the Pva free radicals will be given. (Author)

  14. Discoveries by the Fermi Gamma Ray Space Telescope

    Science.gov (United States)

    Gehrels, Neil

    2011-01-01

    Fermi is a large space gamma-ray mission developed by NASA and the DOE with major contributions from France, Germany, Italy, Japan and Sweden. It was launched in June 2008 and has been performing flawlessly since then. The main instrument is the Large Area Telescope (LAT) operating in the 20 MeV to 300 GeV range and a smaller monitor instrument is the Gamma-ray Burst Monitor (GBM) operating in the 8 keV to 40 MeV range. New findings are occurring every week. Some of the key discoveries are: 1) Discovery of many new gamma-ray pulsars, including gamma-ray only and millisecond pulsars. 2) Detection of high energy gamma-ray emission from globular clusters, most likely due to summed emission from msec pulsars. 3) Discovery of delayed and extended high energy gamma-ray emission from short and long gamma-ray busts. 4) Detection of approximately 250 gamma-ray bursts per year with the GBM instrument. 5) Most accurate measurement of the cosmic ray electron spectrum between 30 GeV and 1 TeV, showing some excess above the conventional diffusion model. The talk will present the new discoveries and their implications.

  15. Behavior of the dynamic magnetic susceptibility in ybco bula ceramics irradiated with gamma rays

    International Nuclear Information System (INIS)

    Leyva Fabelo, A.; Bouza Dominguez, J.; Cruz Inclan, Carlos M.

    2001-01-01

    Using measurements of the ac susceptibility, the behavior with the irradiation dose of YBa2Cu3O7- bulk ceramics synthesized by the classic reaction method in solid state, was studied. A Co60 gamma chamber model MPX-G-25M and a Cs137 source were employed as gamma ray sources. The behavior of the beginning temperature of the normal - superconducting state transition with the exposition dose show, independently of the incident gamma energy, a monotonous growth until reaching a threshold dose, after which, observe a fall, more abrupt in the case of the Co60. This behavior can be explained using the model that postulates the ability of the gamma radiation, in certain dose intervals, to stimulate the structural reordering in the oxygen sublattice. When the irradiation process takes place in the Co60 gamma chamber, the behavior of the superconducting volume fraction of the sample characterizes by the initial sharp fall with the dose, followed with an attenuation of the decrement. In the case of Cs137 irradiation, the behavior of the superconducting volume fraction is similar to the behavior of the Ton with the dose

  16. Feasibility study of gamma-ray medical radiography

    International Nuclear Information System (INIS)

    Alyassin, Abdalmajeid M.; Maqsoud, Hamza A.; Mashat, Ahmad M.; Al-Mohr, Al-Sayed; Abdulwajid, Subhan

    2013-01-01

    This research explores the feasibility of using gamma-ray radiography in medical imaging. We will show that gamma-ray medical radiography has the potential to provide alternative diagnostic medical information to X-ray radiography. Approximately one Ci Am-241 radioactive source which emits mono-energetic 59.5 keV gamma rays was used. Several factors that influence the feasibility of this study were tested. They were the radiation source uniformity, image uniformity, and image quality parameters such as contrast, noise, and spatial resolution. In addition, several gamma-ray and X-ray images were acquired using humanoid phantoms. These images were recorded on computed radiography image receptors and displayed on a standard monitor. Visual assessments of these images were then conducted. The Am-241 radioactive source provided relatively uniform radiation exposure and images. Image noise and image contrast were mainly dependent on the exposure time and source size, whereas spatial resolution was dependent on source size and magnification factor. The gamma-ray humanoid phantom images were of lower quality than the X-ray images mainly due to the low radioactivity used and not enough exposure time. Nevertheless, the gamma-ray images displayed most of the main structures contained in the humanoid phantoms. Higher exposure rates and thus lower exposure times were estimated for different pure Am-241 source sizes that are hypothesized to provide high quality images similar to X-ray images. For instance, a 10 mm source size of pure Am-241 with 7 s exposure time should produce images similar in contrast and noise to X-ray images. This research paves the way for the production and usage of a highly radioactive Am-241 source with the potential to lead to the feasibility of acceptable quality medical gamma-ray radiography. - Highlights: ► Characterized the performance of gamma-ray radiography. ► Displayed medical images of humanoid phantoms using gamma radiography. ► Am-241

  17. Dose and dose rate extrapolation factors for malignant and non-malignant health endpoints after exposure to gamma and neutron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Van; Little, Mark P. [National Cancer Institute, Radiation Epidemiology Branch, Rockville, MD (United States)

    2017-11-15

    Murine experiments were conducted at the JANUS reactor in Argonne National Laboratory from 1970 to 1992 to study the effect of acute and protracted radiation dose from gamma rays and fission neutron whole body exposure. The present study reports the reanalysis of the JANUS data on 36,718 mice, of which 16,973 mice were irradiated with neutrons, 13,638 were irradiated with gamma rays, and 6107 were controls. Mice were mostly Mus musculus, but one experiment used Peromyscus leucopus. For both types of radiation exposure, a Cox proportional hazards model was used, using age as timescale, and stratifying on sex and experiment. The optimal model was one with linear and quadratic terms in cumulative lagged dose, with adjustments to both linear and quadratic dose terms for low-dose rate irradiation (<5 mGy/h) and with adjustments to the dose for age at exposure and sex. After gamma ray exposure there is significant non-linearity (generally with upward curvature) for all tumours, lymphoreticular, respiratory, connective tissue and gastrointestinal tumours, also for all non-tumour, other non-tumour, non-malignant pulmonary and non-malignant renal diseases (p < 0.001). Associated with this the low-dose extrapolation factor, measuring the overestimation in low-dose risk resulting from linear extrapolation is significantly elevated for lymphoreticular tumours 1.16 (95% CI 1.06, 1.31), elevated also for a number of non-malignant endpoints, specifically all non-tumour diseases, 1.63 (95% CI 1.43, 2.00), non-malignant pulmonary disease, 1.70 (95% CI 1.17, 2.76) and other non-tumour diseases, 1.47 (95% CI 1.29, 1.82). However, for a rather larger group of malignant endpoints the low-dose extrapolation factor is significantly less than 1 (implying downward curvature), with central estimates generally ranging from 0.2 to 0.8, in particular for tumours of the respiratory system, vasculature, ovary, kidney/urinary bladder and testis. For neutron exposure most endpoints, malignant and

  18. Effects of gamma-ray irradiation on the optical properties of amorphous Se100-xHgx thin films

    Science.gov (United States)

    Ahmad, Shabir; Islam, Shama; Nasir, Mohd.; Asokan, K.; Zulfequar, M.

    2018-06-01

    In this study, the thermal quenching technique was employed to prepare bulk samples of Se100-xHgx (x = 0, 5, 10, 15). Thin films with a thickness of ∼250 nm were deposited on glass substrates using the thermal evaporation technique. These films were irradiated with gamma rays at doses of 25-100 kGy. The elemental compositions of the as-deposited thin films were confirmed by energy dispersive X-ray analysis and Rutherford backscattering spectrometry. X-ray diffraction analysis confirmed the crystalline nature of these thin films upto the dose of 75 kGy. Fourier transform-infrared spectroscopy showed that the concentration of defects decreased after gamma irradiation. Microstructural analysis by field emission scanning electron microscopy indicated that the grain size increases after irradiation. Optical study based on spectrophotometry showed that the optical band gap values of these films increase after the addition of Hg whereas they decrease after gamma irradiation. We found that the absorption coefficient increases with doses up to 75 kGy but decreases at higher doses. These remarkable shifts in the optical band gap and absorption coefficient values are interpreted in terms of the creation and annihilation of defects, which are the main effects produced by gamma irradiation.

  19. Gamma-ray spectrometry laboratory and in situ: developments and environmental applications

    International Nuclear Information System (INIS)

    Gasser, Estelle

    2014-01-01

    Gamma-ray spectrometry enables determining all γ-ray emitters in a sample with a single measurement. Self-absorption of γ-rays in samples is manifest by a loss or a gain of pulses that results in a poor estimation of the counting efficiency. To characterize a new counting geometry improvements of the existing set-up were made with MCNPX simulations. With the new geometry we could specify absorbed and annual effective doses as well as dose conversion factors for the natural radioisotopes of several building materials and soil samples. Simulations show the influence of detection limits of γ-radiation on dose conversion factors and the need for updating these factors. γ-ray measurements of soil in situ require different counting efficiencies simulated by MCNPX for a semi-infinite source. Two in-situ soil analyses were made, one around a nuclear power and the other for a private company. (author)

  20. The Protective Role of Tempol Against Oxidative Stress-Related Renal Impairment Induced by Gamma Rays in Rats

    International Nuclear Information System (INIS)

    Mekawy, H.M.S.; Elkhouly, W.A.; Tawfik, S.S.

    2015-01-01

    Tempol (4-hydroxy-2,2,6,6-tetramethyl-piperidine-1 oxyl) is a naturally occurring substance that counteracts the harmful and damaging effects of oxidation in animal tissues and has been reported to permeate the biological membranes. In this study, tempol with dose of 18 mg/kg/day for 2 weeks has been shown to be effective in preventing several of the adverse consequences of oxidative stress and inflammation that underlie radiation damage. Adult rats were exposed to a total dose of 6 Gy gamma rays to determine the protective role of tempol on the biochemistry of the injured kidney because gamma rays displayed significant augmentation in renal oxidative modifications markers.The results indicated that plasma renal function tests; urea (Ur), creatinine (Cr), uric acid (UA) and sodium (Na), and plasma renal tubular injury markers; γ -glutamyltransferase ( γ -GT), aspartate aminotransferase (AST), creatine phosphokinase (CPK) and lactate dehydrogenase (LDH), were increased significantly in gamma rays group. In addition, the renal oxidative stress parameters; malondialdehyde (MDA), total cholesterol (TC) and protein carbonyl (PC), were increased significantly, and reduced glutathione (GSH) was decreased significantly in gamma rays group. Moreover, the levels of renal antioxidant enzymes; superoxide dismutase (SOD) and catalase (CAT), were decreased significantly, and myeloperoxidase (MPO) was in creased significantly in gamma rays group.The antioxidant treatment with tempol ameliorates gamma rays-induced biochemical alterations and dysfunction of kidney.Tempol, at levels within tolerable nutritional strategy, reduced the oxidative modification-related renal impairment induced by gamma radiation in rats.

  1. Gamma-ray transients and related astrophysical phenomena

    International Nuclear Information System (INIS)

    Lingenfelter, R.E.; Hudson, H.S.; Worrall, D.M.

    1982-01-01

    The workshop covered the study of the explosive phenomena responsible for the various gamma ray transients. X-ray burster observations and theories were also reviewed with emphasis on their relationship to gamma ray bursts. Recent observational data, particularly from the SMM, HEAO, and VENERA satellites made the workshop especially timely. Major headings include: gamma-ray transients, x-ray bursts, solar transients, and instrumental concepts. Individual items from the workshop were prepared separately for the data base

  2. Cosmic gamma-ray background radiation. Current understandings and problems

    International Nuclear Information System (INIS)

    Inoue, Yoshiyuki

    2015-01-01

    The cosmic gamma-ray background radiation is one of the most fundamental observables in the gamma-ray band. Although the origin of the cosmic gamma-ray background radiation has been a mystery for a long time, the Fermi gamma-ray space telescope has recently measured it at 0.1-820 GeV and revealed that the cosmic GeV gamma-ray background is composed of blazars, radio galaxies, and star-forming galaxies. However, Fermi still leaves the following questions. Those are dark matter contribution, origins of the cosmic MeV gamma-ray background, and the connection to the IceCube TeV-PeV neutrino events. In this proceeding, I will review the current understandings of the cosmic gamma-ray background and discuss future prospects of cosmic gamma-ray background radiation studies. (author)

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

    International Nuclear Information System (INIS)

    Calderon, A.; Calvo, E.; Figueroa, C.F.; Martinez-Rivero, C.; Matorras, F.; Rodrigo, T.; Vila, I.; Virto, A.L.; Arce, P.; Barcala, J.M.; Ferrando, A.; Fuentes, J.; Josa, M.I.; Luque, J.M.; Molinero, A.; Navarrete, J.; Oller, J.C.; Valdivieso, P.; Fenyvesi, A.; Molnar, J.

    2004-01-01

    We report on irradiation studies done to a sample of high-precision electrolytic tiltmeters with gamma-rays, up to a maximum dose of 150 kGy, and neutrons, up to a maximum fluence of 1.5x10 14 cm -2 . The effect of the irradiation on their performance is discussed

  4. Physical changes associated with gamma doses of PM-555 solid-state nuclear track detector

    International Nuclear Information System (INIS)

    Nouh, S.A.

    2004-01-01

    The effect of gamma irradiation on the electrical, molecular and structural properties of copolymers of methacrylic esters and olefins, PM-555 solid-state nuclear track detector was investigated. DC conductivity measurements were studied in the temperature range 293-417 K using solid-state samples of the PM-555 polymer. These samples were irradiated with gamma doses in the range 5-63 kGy. Furthermore, the activation energy was measured, at various temperatures, as a function of the gamma dose. It was found that many changes in electrical resistance of PM-555 polymer could be produced by gamma irradiation via the degradation mechanism. Also, the gamma dose gives an advantage for the increasing correlation between the DC conductivity and the number and mobility of the charge carriers created by the ionizing effect of gamma radiation. Moreover, solutions of different loadings (0.2%, 0.4%, 0.6% and 0.8%) were prepared from the irradiated and non irradiated sheets using pure chloroform as a solvent. The effect of both temperature and gamma dose on the intrinsic viscosity of the liquid samples, as a measure of the mean molecular mass of the PM-555 polymer, were studied. In addition, structural and optical property studies using X-ray diffraction and refractive index measurements were performed on all irradiated and non irradiated PM-555 samples. The results indicate that both the degree of ordering or disordering and the anisotropic character of the PM-555 polymer are dependent on the gamma dose

  5. Overview of high intensity x-ray and gamma-ray sources

    International Nuclear Information System (INIS)

    Prestwich, K.R.; Lee, J.R.; Ramirez, J.J.; Sanford, T.W.L.; Agee, F.J.; Frazier, G.B.; Miller, A.R.

    1987-01-01

    The requirements for intense x-ray and gamma-ray sources to simulate the radiation effects from nuclear weapons has led to the development of several types of terawatt-pulsed power systems. One example of a major gamma-ray source is Aurora, a 10-MV, 1.6-MA, 120-ns four-module, electron-beam generator. Recent requirements to improve the dose rate has led to the Aurora upgrade program and to the development of the 20-MV, 800-kA, 40-ns Hermes-III electron-beam accelerator. The Aurora program includes improvements to the pulsed power system and research on techniques to improve the pulse shape of the electron beam. Hermes III will feature twenty 1-MV, 800-kA induction accelerator cavities supplying energy to a magnetically insulated transmission line adder. Hermes III will become operational in 1988. Intense x-ray sources consist of pulsed power systems that operate with 1-MV to 2-MV output voltages and up to 25-TW output powers. These high powers are achieved with either low impedance electron-beam generators or multimodular pulsed power systems. The low-impedance generators have high voltage Marx generators that store the energy and then sequentially transfer this energy to pulse-forming transmission lines with lower and lower impedance until the high currents are reached. In the multimode machines, each module produces 0.7-TW to 4-TW output pulses, and all of the modules are connected together to supply energy to a single diode

  6. Verification by the FISH translocation assay of historic doses to Mayak workers from external gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sotnik, Natalia V.; Azizova, Tamara V. [Southern Urals Biophysics Institute (SUBI), Ozyorsk, Chelyabinsk Region (Russian Federation); Darroudi, Firouz [Leiden University Medical Center, Department of Toxicogenetics, Leiden (Netherlands); College of North Atlantic, Department of Health Science, Centre for Human Safety and Environmental Research, Doha (Qatar); Ainsbury, Elizabeth A.; Moquet, Jayne E.; Lloyd, David C.; Hone, Pat A.; Edwards, Alan A. [Public Health England, Chilton, Oxfordshire (United Kingdom); Fomina, Janna [Leiden University Medical Center, Department of Toxicogenetics, Leiden (Netherlands)

    2015-11-15

    The aim of this study was to apply the fluorescence in situ hybridization (FISH) translocation assay in combination with chromosome painting of peripheral blood lymphocytes for retrospective biological dosimetry of Mayak nuclear power plant workers exposed chronically to external gamma radiation. These data were compared with physical dose estimates based on monitoring with badge dosimeters throughout each person's working life. Chromosome translocation yields for 94 workers of the Mayak production association were measured in three laboratories: Southern Urals Biophysics Institute, Leiden University Medical Center and the former Health Protection Agency of the UK (hereinafter Public Health England). The results of the study demonstrated that the FISH-based translocation assay in workers with prolonged (chronic) occupational gamma-ray exposure was a reliable biological dosimeter even many years after radiation exposure. Cytogenetic estimates of red bone marrow doses from external gamma rays were reasonably consistent with dose measurements based on film badge readings successfully validated in dosimetry system ''Doses-2005'' by FISH, within the bounds of the associated uncertainties. (orig.)

  7. Gamma-Ray Interactions for Reachback Analysts

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-02

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

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

    OpenAIRE

    Koike, K.; Nakagawa, M.; Koike, C.; Okada, M.; Chihara, H.

    2002-01-01

    Interstellar matter is known to be strongly irradiated by radiation and several types of cosmic ray particles. Simulated interstellar matter, such as forsterite $\\rm Mg_{2}SiO_{4}$, enstatite $\\rm MgSiO_{3}$ and magnesite $\\rm MgCO_{3}$ has been irradiated with the $\\rm ^{60}Co$ gamma-rays in liquid nitrogen, and also irradiated with fast neutrons at 10 K and 70 K by making use of the low-temperature irradiation facility of Kyoto University Reactor (KUR-LTL. Maximum fast neutron dose is $10^{...

  9. Influence of UV Photo-Transfer on Post Irradiated Double Sulphate Poly-Crystals By Gamma And X-rays

    International Nuclear Information System (INIS)

    El-kolaly, M.A.

    2000-01-01

    Solid state thermoluminescence (TL) dosimetry has for many years been the pre-eminent method for quantifying ionizing radiation dose. In this work, thermoluminescence characteristics of the double sulphate (Li Cs So 4 ) poly-crystals have been studied after exposure to different doses from X and gamma radiation. The glue curves showed TL response of three peaks at 75,125,250 degree. The structure of the glue peaks due to X-rays is quite different from that due to gamma rays. UV exposure yields a regeneration of the TL peaks for the post irradiated samples for X or gamma radiation with some changes in the peaks structure especially the third peak. For the post X-ray irradiated crystals, the area under the third glow peak (III) increased linearly with the integrated time of UV exposures till about 30 min. after which no changes were observed; while , for the post gamma-irradiated crystals two linear regions were observed

  10. Gamma-ray spectrometry applied to down-hole logging

    International Nuclear Information System (INIS)

    Dumesnil, P.; Umiastowsky, K.

    1983-11-01

    Gamma-ray spectrometry permits to improve the accuracy of natural gamma, gamma-gamma and neutron-gamma geophysical measurements. The probe developed at Centre d'Etudes Nucleaires de Saclay allows down-hole gamma-ray spectrometry. Among others, this probe can be applied to the uranium content determination by selective natural gamma method, down-hole determination of the ash content in the coal by gamma-gamma selective method and elemental analysis by neutron-gamma method. For the calibration and an exact interpretation of the measurements it is important to know the gamma-ray and neutron characteristics of the different kinds of rocks considered as probabilistic variables

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

    Science.gov (United States)

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

    2018-04-01

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

  12. Gamma-Ray Imaging Spectrometer (GRIS): a new balloon-borne experiment for gamma-ray line astronomy

    International Nuclear Information System (INIS)

    Teegarden, B.J.; Cline, T.L.; Gehrels, N.; Porreca, G.; Tueller, J.; Leventhal, M.; Huters, A.F.; Maccallum, C.J.; Stang, P.D.; Sandia Labs., Albuquerque, NM)

    1985-01-01

    High resolution gamma-ray spectroscopy is a relatively new field that holds great promise for further understanding of high energy astrophysical processes. When the high resolution gamma-ray spectrometer (GRSE) was removed from the GRO payload, a balloon program was initiated to permit continued development and improvement of instrumentation in this field, as well as continued scientific observations. The Gamma-Ray Imaging Spectrometer (GRIS) is one of the experiments selected as part of this program. The instrument contains a number of new and innovative features that are expected to produce a significant improvement in source location accuracy and sensitivity over previous balloon and satellite experiments

  13. High-energy gamma-ray emission in compact binaries

    International Nuclear Information System (INIS)

    Cerutti, Benoit

    2010-01-01

    Four gamma-ray sources have been associated with binary systems in our Galaxy: the micro-quasar Cygnus X-3 and the gamma-ray binaries LS I +61 degrees 303, LS 5039 and PSR B1259-63. These systems are composed of a massive companion star and a compact object of unknown nature, except in PSR B1259-63 where there is a young pulsar. I propose a comprehensive theoretical model for the high-energy gamma-ray emission and variability in gamma-ray emitting binaries. In this model, the high-energy radiation is produced by inverse Compton scattering of stellar photons on ultra-relativistic electron-positron pairs injected by a young pulsar in gamma-ray binaries and in a relativistic jet in micro-quasars. Considering anisotropic inverse Compton scattering, pair production and pair cascade emission, the TeV gamma-ray emission is well explained in LS 5039. Nevertheless, this model cannot account for the gamma-ray emission in LS I +61 degrees 303 and PSR B1259-63. Other processes should dominate in these complex systems. In Cygnus X-3, the gamma-ray radiation is convincingly reproduced by Doppler-boosted Compton emission of pairs in a relativistic jet. Gamma-ray binaries and micro-quasars provide a novel environment for the study of pulsar winds and relativistic jets at very small spatial scales. (author)

  14. Effect of gamma rays on some qualitative and quantitative characters in Zinnia elegans Jacq

    International Nuclear Information System (INIS)

    Venkatachalam, P.; Jayabalan, N.

    1997-01-01

    Mutations were induced in Zinnia elegans Jacq. cv. Crimson Red by using gamma irradiation for plant morphology and flower colour. Significant effects were observed as shown by the increased mean value of plant height, branch number, flower number, and flower diameter up to 7.5 kR dose. Among the gamma-ray doses, only 7.5 kR produced significant morphological changes in Zinnia elegans, which may be due to additive gene effect. Four types of new flower colour mutations were induced: majenta, yellow, red and red with white spots. The number of petals (ray florets) was significantly higher in the mutants over control. Two types of structural anomalies were also identified

  15. Development of gamma-ray-suppression type of small-sized neutron detector based on a 6Li-glass scintillator

    International Nuclear Information System (INIS)

    Matsumoto, T.; Harano, H.; Shimoyama, T.; Kudo, K.; Uritani, A.

    2005-01-01

    A small-sized thermal neutron detector based on a 6 Li-glass scintillator and a plastic optical fiber was developed for measurement of a dose distribution of thermal neutrons in a thermal neutron standard field. A contribution of gamma rays can not be neglected in the neutron measurement with this detector, although the 6 Li-glass scintillator can be distinguishable for the neutrons and the gamma rays by difference of each pulse height. Moreover, to reduce an uncertainty of neutron counts caused by the gamma ray background around a discrimination level, we suggested a gamma-ray-suppression type of small-sized thermal neutron detector with a 6 Li-glass scintillator, a hollow CsI(Tl) scintillator and plastic optical fibers. The detector can reject signals due to the gamma rays with an anti-coincidence method. In the present paper, we evaluated an ability of a gamma-ray suppression of the detector using the EGS4 electron-photon transport Monte-Carlo code with the PRESTA routine. As the results, the sufficient gamma-ray suppression effect was shown. (author)

  16. VHE Gamma-ray Supernova Remnants

    Energy Technology Data Exchange (ETDEWEB)

    Funk, Stefan; /KIPAC, Menlo Park

    2007-01-22

    Increasing observational evidence gathered especially in X-rays and {gamma}-rays during the course of the last few years support the notion that Supernova remnants (SNRs) are Galactic particle accelerators up to energies close to the ''knee'' in the energy spectrum of Cosmic rays. This review summarizes the current status of {gamma}-ray observations of SNRs. Shell-type as well as plerionic type SNRs are addressed and prospect for observations of these two source classes with the upcoming GLAST satellite in the energy regime above 100 MeV are given.

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

    International Nuclear Information System (INIS)

    Ferreto, Helio F.R.; Oliveira, Ana C.F. de; Parra, Duclerc F.; Lugao, Ademar B.

    2013-01-01

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

  18. Shielding effect of clinical x-ray protector and lead glass against annihilation radiation and gamma rays of 99mTc

    International Nuclear Information System (INIS)

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

    2004-01-01

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

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

    Science.gov (United States)

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

    2004-12-01

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

  20. Gamma-rays from decaying dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Bertone, G. [Paris-6 Univ., 75 (France). Inst. d' Astrophysique; Buchmueller, W.; Covi, L.; Ibarra, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2007-10-15

    We study the prospects for detecting gamma-rays from decaying Dark Matter (DM), focusing in particular on gravitino DM in R-parity breaking vacua. Given the substantially different angular distribution of the predicted gamma-ray signal with respect to the case of annihilating DM, and the relatively poor (of order 0.1 ) angular resolution of gamma-ray detectors, the best strategy for detection is in this case to look for an exotic contribution to the gamma-ray flux at high galactic latitudes, where the decaying DM contribution would resemble an astrophysical extragalactic component, similar to the one inferred by EGRET observations. Upcoming experiments such as GLAST and AMS-02 may identify this exotic contribution and discriminate it from astrophysical sources, or place significant constraints on the mass and lifetime of DM particles. (orig.)

  1. Study of X-rays and nuclear gamma -rays in muonic thallium

    CERN Document Server

    Backe, H; Jahnke, U; Kankeleit, E; Pearce, R M; Petitjean, C; Schellenberg, L; Schneuwly, H; Schröder, W U; Walter, H K; Zehnder, A

    1972-01-01

    Energies and intensities of muonic X-rays, nuclear gamma -rays and mu -capture gamma -rays were measured in natural muonic thallium with Ge (Li) detectors. The absolute intensities of higher mu X-rays were reproduced by a cascade calculation starting with a statistical population at n=20 including K-, L- and M-conversion. The electron screening effect was deduced from energies of higher mu X-rays. Eight prompt nuclear gamma -rays were found. This excitation explains the anomalous intensity ratios of the 2p-1s and 3d-2p fine structure components. From the nuclear gamma -rays of the first excited states were deduced: the magnetic h.f. splittings, muonic isomer shifts E2/M1 mixing ratios and the half-life in the presence of the muon in /sup 205/Tl. Evidence for a magnetic nuclear polarization was found. An isotope shift of Delta E=10.35+or-0.25 keV was measured for the 1s/sub 1/2/ state which is compared with data from optical spectroscopy. From an analysis of the time distribution of delayed gamma -rays from mu...

  2. Effect of cysteamine on sister chromatid exchange (SCE) induction by gamma rays

    International Nuclear Information System (INIS)

    Mendiola Cruz, M.T.

    1987-01-01

    The effect of different doses of cysteamine (3, 15 and 150 μg/g bw) on gamma ray-induced SCE was evaluated and compared with the responses obtained with regard to frequency of chromosomal aberrations, frequency of proliferating cells and the rate of cellular proliferating kinetics in mouse bone marrow cells in vivo. Groups of mice were either irradiated, treated with cysteamine and irradiated, only treated with cysteamine or left without treatment for determination of these parameters. The intraperitoneal administration of cysteamine preceding 1 Gy of gamma ray exposure, produces a dose dependent radioprotection on SCE-induction obtaining the greatest effect with 150 μg/g bw. However, this effect was not observed in the mitotic index nor in the average generation time. Chromosomic aberrations in animals irradiated after treatment with cysteamine were also detected. It was not observed any citotoxic or genotoxic effect produced by cysteamine per se. The results suggest that, under the experimental conditions of this study, the SCE are caused by free radicals produced by gamma radiation; not so, the additional damage indexes measured. (author)

  3. gamma. -ray. Present status and problems

    Energy Technology Data Exchange (ETDEWEB)

    Okudaira, K [Rikkyo Univ., Tokyo (Japan). Faculty of Science

    1975-01-01

    As ..gamma..-ray advances straightly through space, the study on cosmic ..gamma..-ray will give the information concerning the origin directly. However, the intensity is weak, and the avoidance of background is a serious problem. The wide-spread components were studied by OSO-3. The intensity of the galactic disc component around 100 MeV was reported as (3.4+-1.0)x10/sup -5/ photons (cm/sup 2/, radian, sec)/sup -1/ by OSO-3 and 0.2x10/sup -4/ photons (cm/sup 2/, radian sec)/sup -1/ by SAS-2, and corresponds to the calculated ..gamma.. yield from ..pi../sup 0/. The strong disc component, so-called galactic center region, has been observed, and is due to the mixture of ..gamma..-ray from ..pi../sup 0/ and inverse Compton ..gamma..-ray. A peak at 476+-24 KeV was found as well as the continuous component. Special care must be taken for the observation of isotropic component, since it is hardly distinguished from the background. It is considered that the isotropic component is due to the inverse Compton scattering of 3/sup 0/K radiation in super-galactic space and the contribution from outer galaxy. The nearest point source of ..gamma..-ray is the sun. Among the other point sources, the crab nebula is the most reliable one. The energy flux of pulse component showed the spectrum of E/sup -1/. ..gamma..-ray bursts were observed by man-made satellites Vela-5 and 6. Theoretical explanation is still incomplete regarding the bursts. (Kato, T.).

  4. Influence of pre-sowing irradiation of soya seeds with low doses of gamma rays on the yields of grain and on the content of crude protein in the grain

    International Nuclear Information System (INIS)

    Nikolov, Ch.V.

    1985-01-01

    Pre-sowing irradiation of air-dry soya seeds of the Hodson variety, calibrated in size and humidity (12%), with gamma rays in the range of relatively low intensities of irradiation of 0.27 to 5 Gy/min and doses of 10 to 20 Gy increases both the yield of grain and the content of crude protein in the grain in relation to the absolute dry matter. The dependence of radiostimulation effect on the factors of the environment cannot be reason for neglecting it as a posssible reserve for increasing the yield of grain from soya and the content of crude protein in the grain. Possible results are exspected from production experiments with pre-sowing irradiation of seeds of Hodson variety using gamma rays in the range of the above intensities and doses

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

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Ryosuke; Fukazawa, Yasushi; Kanda, Yuka; Shiki, Kensei; Kawabata, Miho; Nakaoka, Tatsuya; Takaki, Katsutoshi; Takata, Koji; Ui, Takahiro [Department of Physical Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Nalewajko, Krzysztof; Madejski, Greg M. [Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road M/S 29, Menlo Park, CA 94025 (United States); Uemura, Makoto; Tanaka, Yasuyuki T.; Kawabata, Koji S.; Akitaya, Hiroshi; Ohsugi, Takashi [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Schinzel, Frank K. [Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131 (United States); Moritani, Yuki [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Sasada, Mahito [Institute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Yamanaka, Masayuki, E-mail: itoh@hep01.hepl.hiroshima-u.ac.jp, E-mail: itoh@hp.phys.titech.ac.jp [Department of Physics, Faculty of Science and Engineering, Konan University, Okamoto, Kobe, Hyogo 658-8501 (Japan); and others

    2016-12-10

    Blazars are highly variable active galactic nuclei that emit radiation at all wavelengths from radio to gamma rays. Polarized radiation from blazars is one key piece of evidence for synchrotron radiation at low energies, and it also varies dramatically. The polarization of blazars is of interest for understanding the origin, confinement, and propagation of jets. However, even though numerous measurements have been performed, the mechanisms behind jet creation, composition, and variability are still debated. We performed simultaneous gamma-ray and optical photopolarimetry observations of 45 blazars between 2008 July and 2014 December to investigate the mechanisms of variability and search for a basic relation between the several subclasses of blazars. We identify a correlation between the maximum degree of optical linear polarization and the gamma-ray luminosity or the ratio of gamma-ray to optical fluxes. Since the maximum polarization degree depends on the condition of the magnetic field (chaotic or ordered), this result implies a systematic difference in the intrinsic alignment of magnetic fields in parsec-scale relativistic jets between different types of blazars (flat-spectrum radio quasars vs. BL Lacs) and consequently between different types of radio galaxies (FR I versus FR II).

  6. A study on gamma dose rate in Seoul (I)

    International Nuclear Information System (INIS)

    Kim, You Hyun; Kim, Chang Kyun; Choi, Jong Hak; Kim, Jeong Min

    2001-01-01

    This study was conducted to find out gamma dose rate in Seoul, from January to December in 2000, and the following results were achieved : The annual gamma dose rate in Seoul was 17.24 μR/hr as average. The annual gamma dose rate in subway of Seoul was 14.96 μR/hr as average. The highest annual gamma dose rate was Dong-daemon ku. Annual gamma dose rate in Seoul was higher autumn than winter

  7. Effects of gamma rays on non-vascular smooth muscles contractions (rat small intestine)

    International Nuclear Information System (INIS)

    Azroony, R.; Ksies, F.; Alya, G.

    2003-03-01

    In this experiment, the contractile response evoked by activating the membranous cholinergic and adrenergic receptors in the smooth muscular fibres isolated from jejunum in rat small intestine is studied. Also the effect of gamma rays on regulating this contractile response after exposing the whole body of the animals to different doses of gamma rays (3, 5 and 7 Gy) emitted from 60 Co source is studied. Results show that irradiation lessens the sensitivity of muscarinic cholinergic receptors to their agonists in a dose dependent manner. And there is an important shift on irradiated rats where the maximum effect of acetylcholine (E max) can be obtained in higher concentrations of acetylcholine. Concerning the effects of gamma rays on adrenergic receptors, our results show that irradiation, also, decreases the sensitivity of α1 adrenergic receptors to their agonists, and this decrease is represented in a decrease of the irradiated muscular fibers response to the inhibitory effect of phenylephrine (more specific to α1 adrenergic receptors than α2 adrenergic receptors) in a dose dependent manner. While we have found that α2 adrenergic receptors have no important effect on regulating the contractile response of the smooth muscular fibers in the rat jejunum neither in smooth muscular fibers isolated from control animals nor in those fibers which where isolated from irradiated animals. (author)

  8. Gamma-ray spectroscopy on irradiated fuel rods

    International Nuclear Information System (INIS)

    Terremoto, Luis Antonio Albiac

    2009-01-01

    The recording of gamma-ray spectra along an irradiated fuel rod allows the fission products to be qualitatively and quantitatively examined. Among all nondestructive examinations performed on irradiated fuel rods by gamma-ray spectroscopy, the most comprehensive one is the average burnup measurement, which is quantitative. Moreover, burnup measurements by means of gamma-ray spectroscopy are less time-consuming and waste-generating than burnup measurements by radiochemical, destructive methods. This work presents the theoretical foundations and experimental techniques necessary to measure, using nondestructive gamma-ray spectroscopy, the average burnup of irradiated fuel rods in a laboratory equipped with hot cells. (author)

  9. GAMMA RAYS FROM STAR FORMATION IN CLUSTERS OF GALAXIES

    International Nuclear Information System (INIS)

    Storm, Emma M.; Jeltema, Tesla E.; Profumo, Stefano

    2012-01-01

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

  10. Skin dose assessment in routine personnel beta/gamma dosimetry

    International Nuclear Information System (INIS)

    Christensen, P.

    1980-01-01

    The International Commission on Radiological Protection (Publication 26) has recommended a tissue depth of 5 to 10 mg.cm -2 for skin dose assessments. This requirement is generally not fulfilled by routine monitoring procedures because of practical difficulties in using very thin dosemeters with low sensitivity and therefore a high minimum detectable dose. Especially for low-energy beta-ray exposures underestimations of the skin dose by a factor of more than ten may occur. Low-transparent graphite-mixed sintered LiF and Li 2 B 4 0 7 : Mn dosemeters were produced which show a skin-equivalent response to beta and gamma exposures over a wide range of energies. These have found wide-spread application for extremity dosimetry but have not yet been generally introduced in routine personnel beta/gamma monitoring. The following adaptations of existing routine monitoring systems for improved skin dose assessments have been investigated: 1) Placement of a supplementary, thin, skin-dose equivalent dosemeter in the TLD badge to give additional information on low-energy exposures. 2) Introduction of a second photomultiplier in the read-out chamber which enables a simultaneous determination of emitted TL from both sides of the dosemeter separately. This method makes use of the selfshielding of the dosemeter to give information on the low-energy dose contribution. 3) By diffusion of Li 2 B 4 0 7 into solid LiF-dosemeters it was possible to produce a surface layer with a new distinct glow-peak at about 340 deg C which is not present in the undiffused part of the LiF chip, and which can be utilized for the assessment of the skin-dose. Data on energy response and accuracy of dose measurement for beta/gamma exposures are given for the three methods and advantages and disadvantages are discussed (H.K.)

  11. Total integrated dose testing of solid-state scientific CD4011, CD4013, and CD4060 devices by irradiation with CO-60 gamma rays

    Science.gov (United States)

    Dantas, A. R. V.; Gauthier, M. K.; Coss, J. R.

    1985-01-01

    The total integrated dose response of three CMOS devices manufactured by Solid State Scientific has been measured using CO-60 gamma rays. Key parameter measurements were made and compared for each device type. The data show that the CD4011, CD4013, and CD4060 produced by this manufacturers should not be used in any environments where radiation levels might exceed 1,000 rad(Si).

  12. Upgrade of the JET gamma-ray cameras

    International Nuclear Information System (INIS)

    Soare, S.; Curuia, M.; Anghel, M.; Constantin, M.; David, E.; Craciunescu, T.; Falie, D.; Pantea, A.; Tiseanu, I.; Kiptily, V.; Prior, P.; Edlington, T.; Griph, S.; Krivchenkov, Y.; Loughlin, M.; Popovichev, S.; Riccardo, V; Syme, B.; Thompson, V.; Lengar, I.; Murari, A.; Bonheure, G.; Le Guern, F.

    2007-01-01

    Full text: The JET gamma-ray camera diagnostics have already provided valuable information on the gamma-ray imaging of fast ion in JET plasmas. The applicability of gamma-ray imaging to high performance deuterium and deuterium-tritium JET discharges is strongly dependent on the fulfilment of rather strict requirements for the characterisation of the neutron and gamma-ray radiation fields. These requirements have to be satisfied within very stringent boundary conditions for the design, such as the requirement of minimum impact on the co-existing neutron camera diagnostics. The JET Gamma-Ray Cameras (GRC) upgrade project deals with these issues with particular emphasis on the design of appropriate neutron/gamma-ray filters ('neutron attenuators'). Several design versions have been developed and evaluated for the JET GRC neutron attenuators at the conceptual design level. The main design parameter was the neutron attenuation factor. The two design solutions, that have been finally chosen and developed at the level of scheme design, consist of: a) one quasi-crescent shaped neutron attenuator (for the horizontal camera) and b) two quasi-trapezoid shaped neutron attenuators (for the vertical one). The second design solution has different attenuation lengths: a short version, to be used together with the horizontal attenuator for deuterium discharges, and a long version to be used for high performance deuterium and DT discharges. Various neutron-attenuating materials have been considered (lithium hydride with natural isotopic composition and 6 Li enriched, light and heavy water, polyethylene). Pure light water was finally chosen as the attenuating material for the JET gamma-ray cameras. The neutron attenuators will be steered in and out of the detector line-of-sight by means of an electro-pneumatic steering and control system. The MCNP code was used for neutron and gamma ray transport in order to evaluate the effect of the neutron attenuators on the neutron field of the

  13. Dose Distribution of Gamma Irradiators

    International Nuclear Information System (INIS)

    Park, Seung Woo; Shin, Sang Hun; Son, Ki Hong; Lee, Chang Yeol; Kim, Kum Bae; Jung, Hai Jo; Ji, Young Hoon

    2010-01-01

    Gamma irradiator using Cs-137 have been widely utilized to the irradiation of cell, blood, and animal, and the dose measurement and education. The Gamma cell 3000 Elan (Nordion International, Kanata, Ontario, Canada) irradiator was installed in 2003 with Cs-137 and dose rate of 3.2 Gy/min. And the BioBeam 8000 (Gamma-Service Medical GmbH, Leipzig, Germany) irradiator was installed in 2008 with Cs-137 and dose rate of 3.5 Gy/min. Our purpose was to evaluate the practical dosimetric problems associated with inhomogeneous dose distribution within the irradiated volume in open air state using glass dosimeter and Gafchromic EBT film dosimeter for routine Gamma irradiator dosimetry applications at the KIRAMS and the measurements were compared with each other. In addition, an user guideline for useful utilization of the device based on practical dosimetry will be prepared. The measurement results of uniformity of delivered dose within the device showed variation more than 14% between middle point and the lowest position at central axis. Therefore, to maintain dose variation within 10%, the criteria of useful dose distribution, for research radiation effects, the irradiated specimen located at central axis of the container should be placed within 30 mm from top and bottom surface, respectively. In addition, for measurements using the film, the variations of dose distribution were more then 50% for the case of less than 10 second irradiation, mostly within 20% for the case of more than 20 second irradiation, respectively. Therefore, the irradiation experiments using the BioBeam 8000 irradiator are recommended to be used for specimen required at least more than 20 second irradiation time.

  14. Gamma-Ray Pulsar Studies With GLAST

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, D.J.; /NASA, Goddard

    2011-11-23

    Some pulsars have their maximum observable energy output in the gamma-ray band, offering the possibility of using these high-energy photons as probes of the particle acceleration and interaction processes in pulsar magnetospheres. After an extended hiatus between satellite missions, the recently-launched AGILE mission and the upcoming Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) will allow gamma-ray tests of the theoretical models developed based on past discoveries. With its greatly improved sensitivity, better angular resolution, and larger energy reach than older instruments, GLAST LAT should detect dozens to hundreds of new gamma-ray pulsars and measure luminosities, light curves, and phase-resolved spectra with unprecedented resolution. It will also have the potential to find radio-quiet pulsars like Geminga, using blind search techniques. Cooperation with radio and X-ray pulsar astronomers is an important aspect of the LAT team's planning for pulsar studies.

  15. Egret observations of the extragalactic gamma-ray emission

    DEFF Research Database (Denmark)

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

    1998-01-01

    The all-sky survey in high-energy gamma rays (E > 30 MeV) carried out by EGRET aboard the Compton Gamma Ray Observatory provides a unique opportunity to examine in detail the diffuse gamma-ray emission. The observed diffuse emission has a Galactic component arising from cosmic-ray interactions wi...

  16. Sensitivity of Gamma-Ray Detectors to Polarization

    OpenAIRE

    Yadigaroglu, I. -A.

    1996-01-01

    Previous studies have shown that the largest gamma-ray detector to date, EGRET, does not have useful polarization sensitivity. We have explored here some improved approaches to analyzing gamma-ray pair production events, leading to important gains in sensitivity to polarization. The performance of the next generation gamma-ray instrument GLAST is investigated using a detailed Monte Carlo simulation of the complete detector.

  17. Bulk density calculations from prompt gamma ray yield

    International Nuclear Information System (INIS)

    Naqvi, A.A.; Nagadi, M.M.; Al-Amoudi, O.S.B.; Maslehuddin, M.

    2006-01-01

    Full text: The gamma ray yield from a Prompt Gamma ray Neutron Activation Analysis (PGNAA) setup is a linear function of element concentration and neutron flux in a the sample with constant bulk density. If the sample bulk density varies as well, then the element concentration and the neutron flux has a nonlinear correlation with the gamma ray yield [1]. The measurement of gamma ray yield non-linearity from samples and a standard can be used to estimate the bulk density of the samples. In this study the prompt gamma ray yield from Blast Furnace Slag, Fly Ash, Silica Fumes and Superpozz cements samples have been measured as a function of their calcium and silicon concentration using KFUPM accelerator-based PGNAA setup [2]. Due to different bulk densities of the blended cement samples, the measured gamma ray yields have nonlinear correlation with calcium and silicon concentration of the samples. The non-linearity in the yield was observed to increase with gamma rays energy and element concentration. The bulk densities of the cement samples were calculated from ratio of gamma ray yield from blended cement and that from a Portland cement standard. The calculated bulk densities have good agreement with the published data. The result of this study will be presented

  18. Airborne gamma-ray spectrometry

    DEFF Research Database (Denmark)

    Hovgaard, Jens

    A new method - Noise Adjusted Singular Value Decomposition, NASVD - for processing gamma-ray spectra has been developed as part of a Ph.D. project. By using this technique one is able to decompose a large set of data - for example from airborne gamma-ray surveys - into a few spectral components....... By knowing the spectral components and their amplitudes in each of the measured spectra one is able to extract more information from the data than possible with the methods used otherwise....

  19. Energy- and time-resolved detection of prompt gamma-rays for proton range verification.

    Science.gov (United States)

    Verburg, Joost M; Riley, Kent; Bortfeld, Thomas; Seco, Joao

    2013-10-21

    In this work, we present experimental results of a novel prompt gamma-ray detector for proton beam range verification. The detection system features an actively shielded cerium-doped lanthanum(III) bromide scintillator, coupled to a digital data acquisition system. The acquisition was synchronized to the cyclotron radio frequency to separate the prompt gamma-ray signals from the later-arriving neutron-induced background. We designed the detector to provide a high energy resolution and an effective reduction of background events, enabling discrete proton-induced prompt gamma lines to be resolved. Measuring discrete prompt gamma lines has several benefits for range verification. As the discrete energies correspond to specific nuclear transitions, the magnitudes of the different gamma lines have unique correlations with the proton energy and can be directly related to nuclear reaction cross sections. The quantification of discrete gamma lines also enables elemental analysis of tissue in the beam path, providing a better prediction of prompt gamma-ray yields. We present the results of experiments in which a water phantom was irradiated with proton pencil-beams in a clinical proton therapy gantry. A slit collimator was used to collimate the prompt gamma-rays, and measurements were performed at 27 positions along the path of proton beams with ranges of 9, 16 and 23 g cm(-2) in water. The magnitudes of discrete gamma lines at 4.44, 5.2 and 6.13 MeV were quantified. The prompt gamma lines were found to be clearly resolved in dimensions of energy and time, and had a reproducible correlation with the proton depth-dose curve. We conclude that the measurement of discrete prompt gamma-rays for in vivo range verification of clinical proton beams is feasible, and plan to further study methods and detector designs for clinical use.

  20. Multiple Gamma-Ray Detection Capability of a CeBr3 Detector for Gamma Spectroscopy

    Directory of Open Access Journals (Sweden)

    A. A. Naqvi

    2017-01-01

    Full Text Available The newly developed cerium tribromide (CeBr3 detector has reduced intrinsic gamma-ray activity with gamma energy restricted to 1400–2200 keV energy range. This narrower region of background gamma rays allows the CeBr3 detector to detect more than one gamma ray to analyze the gamma-ray spectrum. Use of multiple gamma-ray intensities in elemental analysis instead of a single one improves the accuracy of the estimated results. Multigamma-ray detection capability of a cylindrical 75 mm × 75 mm (diameter × height CeBr3 detector has been tested by analyzing the chlorine concentration in water samples using eight chlorine prompt gamma rays over 517 to 8578 keV energies utilizing a D-D portable neutron generator-based PGNAA setup and measuring the corresponding minimum detection limit (MDC of chlorine. The measured MDC of chlorine for gamma rays with 517–8578 keV energies varies from 0.07 ± 0.02 wt% to 0.80 ± 0.24. The best value of MDC was measured to be 0.07 ± 0.02 wt% for 788 keV gamma rays. The experimental results are in good agreement with Monte Carlo calculations. The study has shown excellent detection capabilities of the CeBr3 detector for eight prompt gamma rays over 517–8578 keV energy range without significant background interference.

  1. Observational techniques of gamma rays astronomy in low energy

    International Nuclear Information System (INIS)

    Costa, J.M. da.

    1982-02-01

    Due to the absorption of great part of the gamma-ray spectrum of cosmic origin, by the earth's atmosphere at heights above 20Km, gamma-ray astronomy achieved its full development only after the advent of the space age. Ballons and satellites are the space vehicles which have been used to transport gamma-ray telescopes to observational heights in the atmosphere, or out of it. The results of these experiments can determine the sources, the energy spectra and the intensities of the cosmic gamma-rays, and provide other important information of astrophysical interest. The detection of gamma-rays of cosmic origin is very difficult. The observational techniques used in gamma-ray astronomy are dependent on the energy range of the gamma-rays which one desires to detect. The most common telescopes of low energy gamma-ray astronomy (50KeV - 20MeV) use NaI(Tl) scintillators, or germanium diodes, as principal detectors, surrounded by an active shield (anticoincidence) of organic or inorganic scintillators. (Author) [pt

  2. Possible galactic origin of. gamma. -ray bursts

    Energy Technology Data Exchange (ETDEWEB)

    Manchanda, R K; Ramsden, D [Southampton Univ. (UK). Dept. of Physics

    1977-03-31

    It is stated that extragalactic models for the origin of non-solar ..gamma..-ray bursts include supernova bursts in remote galaxies, and the collapse of the cores of active stars, whilst galactic models are based on flare stars, thermonuclear explosions in neutron stars and the sudden accretion of cometary gas on to neutron stars. The acceptability of any of these models may be tested by the observed size spectrum of the ..gamma..-ray bursts. The extragalactic models predict a power law spectrum with number index -1.5, whilst for the galactic models the number index will be -1. Experimental data on ..gamma..-ray bursts is, however, still meagre, and so far only 44 confirmed events have been recorded by satellite-borne instruments. The number spectrum of the observed ..gamma..-ray bursts indicates that the observed distribution for events with an energy < 10/sup -4/ erg/cm/sup 2/ is flat; this makes the choice of any model completely arbitrary. An analysis of the observed ..gamma..-ray events is here presented that suggests very interesting possibilities for their origin. There appears to be a preferred mean energy for ..gamma..-ray bursts; some 90% of the recorded events show a mean energy between 5 x 10/sup -5/ and 5 x 10/sup -4/ erg/cm/sup 2/, contrary to the predicted characteristics of the number spectrum of various models. A remarkable similarity is found between the distribution of ..gamma..-ray bursts and that of supernova remnants, suggesting a genetic relationship between the two and the galactic origin of the ..gamma..-ray bursts, and the burst source could be identified with completely run down neutron stars, formed during supernova explosions.

  3. Terrestrial gamma-ray flashes

    Science.gov (United States)

    Marisaldi, Martino; Fuschino, Fabio; Labanti, Claudio; Tavani, Marco; Argan, Andrea; Del Monte, Ettore; Longo, Francesco; Barbiellini, Guido; Giuliani, Andrea; Trois, Alessio; Bulgarelli, Andrea; Gianotti, Fulvio; Trifoglio, Massimo

    2013-08-01

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

  4. Terrestrial gamma-ray flashes

    International Nuclear Information System (INIS)

    Marisaldi, Martino; Fuschino, Fabio; Labanti, Claudio; Tavani, Marco; Argan, Andrea; Del Monte, Ettore; Longo, Francesco; Barbiellini, Guido; Giuliani, Andrea; Trois, Alessio; Bulgarelli, Andrea; Gianotti, Fulvio; Trifoglio, Massimo

    2013-01-01

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

  5. Prompt gamma-ray activation analysis (PGAA)

    International Nuclear Information System (INIS)

    Kern, J.

    1996-01-01

    The paper deals with a brief description of the principles of prompt gamma-ray activation analysis (PGAA), with the detection of gamma-rays, the PGAA project at SINQ and with the expected performances. 8 figs., 3 tabs., 10 refs

  6. Prompt gamma-ray activation analysis (PGAA)

    Energy Technology Data Exchange (ETDEWEB)

    Kern, J [Fribourg Univ. (Switzerland). Inst. de Physique

    1996-11-01

    The paper deals with a brief description of the principles of prompt gamma-ray activation analysis (PGAA), with the detection of gamma-rays, the PGAA project at SINQ and with the expected performances. 8 figs., 3 tabs., 10 refs.

  7. Gamma-Ray Bursts: 4th Huntsville Symposium. Proceedings

    International Nuclear Information System (INIS)

    Meegan, C.A.; Preece, R.D.; Koshut, T.M.

    1998-01-01

    These proceedings represent papers presented at the Fourth Huntsville Gamma-Ray Bursts Symposium held in September, 1997 in Huntsville, Alabama, USA. This conference occurred at a crucial time in the history of the gamma-ray burst research. In early 1997, 30 years after the detection of the first gamma-ray burst by the Vela satellites, counterparts to bursts were finally detected at optical and radio wavelengths. The symposium attracted about 200 scientists from 16 countries. Some of the topics discussed include gamma-ray burst spectra, x-ray observations, optical observations, radio observations, host galaxies, shocks and afterglows and models of gamma-ray bursts. There were 183 papers presented, out of these, 16 have been abstracted for the Energy Science and Technology database

  8. The supernova-gamma-ray burst-jet connection.

    Science.gov (United States)

    Hjorth, Jens

    2013-06-13

    The observed association between supernovae and gamma-ray bursts represents a cornerstone in our understanding of the nature of gamma-ray bursts. The collapsar model provides a theoretical framework for this connection. A key element is the launch of a bipolar jet (seen as a gamma-ray burst). The resulting hot cocoon disrupts the star, whereas the (56)Ni produced gives rise to radioactive heating of the ejecta, seen as a supernova. In this discussion paper, I summarize the observational status of the supernova-gamma-ray burst connection in the context of the 'engine' picture of jet-driven supernovae and highlight SN 2012bz/GRB 120422A--with its luminous supernova but intermediate high-energy luminosity--as a possible transition object between low-luminosity and jet gamma-ray bursts. The jet channel for supernova explosions may provide new insights into supernova explosions in general.

  9. Catalog of gamma-rays unplaced in radioactive decay schemes

    International Nuclear Information System (INIS)

    Narita, Tsutomu; Kitao, Kensuke.

    1991-03-01

    A catalog is made for gamma-rays emitted in decay of radioactive nuclides but not placed in their decay schemes. It consists of two tables. In Table 1, the number of these unplaced gamma-ray components by a nuclide is given together with the fraction of total intensity of these gamma-rays to that of all observed gamma-rays. In Table 2, the unplaced gamma-rays are arranged in order of increasing energy. Each line of this table contains the gamma-ray energy, intensity, nuclide identification, and energies and intensities of the most prominent gamma-rays from the decay of the radionuclides. This catalog is a compilation from Evaluated Nuclear Structure Data File (ENSDF) maintained by National Nuclear Data Center at Brookhaven National Laboratory, of at February 1990. (author)

  10. Study on the viability of peach and apple pollen treated with gamma rays 60Co

    International Nuclear Information System (INIS)

    Filev, K.; Angelov, A.

    1976-01-01

    Pollen from Marygold peach and from Golden Delicious apple varieties was treated with gamma-rays at rates of 0.5, 1.5, 10.0, 50.0, 100, 200, 300, 400 and 500 kR, the irradiation intensity being 1350 r/min. Results point to a different influence of gamma-rays irradiation on the pollen germination. Apple pollen proved more radiosensitive. Least dose of o.5 kR exerted a stimulative effect in the pollen germination. As the irradiation dose rcse, the germination percentage declined. Doses of over 400 kR destroyed completely pollen viability in both fruit species. A linear semi-logarithmical dependence was ascertained between the irradiation rate and pollen germination. 5 and 10 kR proved most suitable for the purposes of the experimental mutagenesis at peach and apple pollen irradiation. (author)

  11. Protective Role of Emodin in Reducing The Gamma Rays Induced Hazardous Effects On The Tongue of Diabetic or Normoglycaemic Mice

    International Nuclear Information System (INIS)

    Haggag, M.G.; Kazem, H.H.

    2013-01-01

    Ionizing radiation leads to damage at various cellular and sub-cellular levels and can be prevented by radio protectors. There is a need for natural prospective radio protectors that protect normal tissues from ionizing radiation in patients receiving high doses of radiation for treating malignant neoplasms. The study aimed to evaluate the potential protective role of emodin in reducing the severity of gamma rays-induced hazardous damage in the tongue of normoglycaemic and diabetic mice. Sixty-four male mice were randomly divided into 8 experimental groups: control group received vehicle, emodin group received daily emodin dose of 4g/kg orally for a week, diabetes mellitus (DM) group in which DM was induced by streptozotocin (STZ) treatment, emodin + DM received emodin for a week + STZ treatment, irradiated group submitted to 4 Gy of gamma rays and received vehicle for a week, gamma rays + DM group received gamma rays + STZ treatment, gamma rays + emodin group received gamma rays + emodin for a week, and gamma rays + DM + emodin group received gamma rays + STZ treatment + emodin for a week. Tongue and serum of mice were biochemically examined for screening gamma radiation and diabetic damages and the efficacy of emodin in ameliorating these damaging effects. The levels of cellular thiols such as reduced glutathione (GSH), oxidized glutathione (GSSG), total thiols (TT) and lipid peroxidation products; malondialdehyde (MDA) and conjugated dienes (CD), were assessed in tongue tissues. Tongue antioxidant enzymes; gamma glutamyl transferase (GGT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and glucose-6-phosphatase (G-6-P), were measured and serum glucose level was estimated. The results revealed alterations of the levels of cellular thiols and antioxidant enzymes in tongue and the level of glucose in serum of gamma irradiated diabetic mice were ameliorated in mice groups received emodin treatment. The results suggest that emodin treatment (4 g

  12. Near stellar sources of gamma-ray bursts

    OpenAIRE

    Luchkov, B. I.; Markin, P. D.

    2012-01-01

    Correlation analysis of gamma-ray burst coordinates and nearby stars, registered on 2008-2011, revealed 5 coincidences with angular accuracy better than 0.1 degree. The random probability is $7\\times 10^{-7}$, so evidencing that coincident stars are indeed gamma-ray burst sources. The proposed method should be continued in order to provide their share in common balance of cosmic gamma-ray bursts.

  13. Gamma rays from the interstellar medium

    International Nuclear Information System (INIS)

    Bloemen, J.B.G.M.

    1985-01-01

    This thesis describes new gamma-ray views on cosmic rays and the interstellar medium. The author describes the COS-B data base and the pre-launch and in-flight calibration data used for all analyses. Diffuse galactic gamma radiation (> 50 MeV) may be either a result of cosmic-ray-matter interactions, or of the cosmic-ray electrons with the interstellar radiation field (mainly at optical and infrared wavelengths), through the inverse-Compton process. A detailed comparison between the gamma-ray observations of the large complex of interstellar clouds in Orion and Monoceros and the CO and HI surveys of this region is given. It gives insight into the cloud penetration of cosmic rays and in the relation between CO detections and molecular hydrogen column densities. Next, the radial distribution of gamma rays in the Galaxy is studied, as well as the galactic centre (more precisely, the central 400 pc), which contains a large concentration of CO molecules. The H 2 /CO abundance and the cosmic-ray density in the galactic centre are discussed and compared to the findings for the galactic disk. In various analyses in this thesis a likelihood-ratio method is applied for parameter estimation and hypothesis testing. A general description of this method is added as an appendix. (Auth.)

  14. Review of GRANAT observations of gamma-ray bursts

    DEFF Research Database (Denmark)

    Terekhov, O.; Denissenko, D.; Sunyaev, R.

    1995-01-01

    The GRANAT observatory was launched into a high apogee orbit on 1 December, 1989. Three instruments onboard GRANAT - PHEBUS, WATCH and SIGMA are able to detect gamma-ray bursts in a very broad energy range from 6 keV up to 100 MeV. Over 250 gamma-ray bursts were detected. We discuss the results...... of the observations of the time histories and spectral evolution of the detected events provided by the different instruments in different energy ranges. Short Gamma-Ray Bursts ( 2 s) events. Evidence of the existence...... of four differently behaving componenents in gamma-ray burst spectra is discussed. Statistical properties of the gamma-ray burst sources based on the 5 years of observations with (∼ 10−6 erg/cm2) sensitivity as well as the results of high sensitivity (∼ 10−8 erg/cm2) search for Gamma-Ray Bursts within...

  15. The Study of Radiation of Gamma-Ray Background at Sedimentology Laboratorium, P3TIR, BATAN, Using Gamma Spectrometry

    International Nuclear Information System (INIS)

    Lubis, Ali Arman; Aliyanta, Barokah; Darman

    2002-01-01

    The measurement of background radiation of gamma-ray has been done at Sedimentology Laboratory, SDAL building, P3TIR, BATAN using gamma spectrometer. The measurement was done without shielding with the range of energy between 50 keV and 1500 keV. The identified radiations are coming from environmental radionuclide and man-made radionuclide as well with 32 energy peaks. The environmental radionuclides are from Uranium series, Thorium series, and 4 0 K having dose rate of 12.510 ± O.980, 36.408 ± 3.243, 9.455 ±O.016 n Sv/day, respectively, whilst man-made radionuclide is 6 O C o having dose rate of O.136 ±O.078 n Sv/day

  16. Gamma-ray dose rate increase at rainfall events and their air-mass origins

    International Nuclear Information System (INIS)

    Iyogi, Takashi; Hisamatsu, Shun'ichi; Inaba, Jiro

    2007-01-01

    The environmental γ-ray dose rate and precipitation rates were measured at our institute, in Rokkasho, Aomori, Japan. We analyzed 425 rainfall events in which the precipitation rate was over 0.5 mm from April through November during the years 2003 to 2005. Backward trajectories for 5 d starting from 1000 m above Rokkasho at the time of the maximum dose rate in a rainfall event, were calculated by using the HYSPLIT model of the NOAA Air Resources Laboratory. The trajectories for 5 d were classified by visual inspection according to the passage areas; Pacific Ocean, Asian Continent and Japan Islands. The increase of cumulative environmental γ-ray dose during a rainfall event was plotted against the precipitation in the event, and their relationship was separately examined according to the air-mass passage area, i.e. origin of the air-mass. Our results showed that the origin of air-mass was an important factor affecting the increase of environmental γ-ray dose rate by rainfall. (author)

  17. Ultra-high energy cosmic rays and prompt TeV gamma rays from ...

    Indian Academy of Sciences (India)

    physics pp. 789-792. Ultra-high energy cosmic rays and prompt. TeV gamma rays from gamma ray bursts ... The origin of the observed ultra-high energy cosmic ray (UHECR) events with ... are proton and electron rest mass, respectively.

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

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, S [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Sinha, N K [Innovative Design Engineering and Synthesis Section, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Gayathri, N [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Ponraju, D [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Dash, S [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Tyagi, A K [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Raj, Baldev [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India)

    2007-02-07

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

  19. Mutagenic effect of gamma-rays on improvement of yield attributing traits of greengram (Vigna radiata (L.) Wilczek)

    International Nuclear Information System (INIS)

    Das, T.R.; Baisakh, B.

    2014-01-01

    Seed samples of two morphologically distinct varieties (Sujata and OBGG-52) of greengram were treated with three doses of Gamma-rays (200 Gy, 400 Gy and 600 Gy). Mutagenic treatments in general showed reduction in mean values of germination, survival and plant growth traits in comparison to control in M 1 generation and the magnitude of reduction was directly related to the dose of the mutagens. The spectrum of chlorophyll mutations includes albina, xantha, chlorina, striata and viridis in both the varieties. The varied morphological mutations observed in leaf of both the genotypes were tricotyledonary, quadrifoliate, pentafoliate and lobed leaf. Early flowering, late flowering, tall plant, trailing type, profused poded, bold poded and sterile plant were also observed as an effect of mutagen in both the genotypes. The M 2 populations showed wider range of variations than the parent varieties. Magnitude of changes varied with mutagen dose and the varieties. Higher the dose of treatment, greater the shift in the mean and variance of different yield parameters. Genetic advance estimates showed that selection in M 2 populations would be effective in improving the yield/plant. Following selection among M 2 plants and M 3 progenies on the basis of higher yield, high yielding mutant cultures in both varieties were isolated in M 4 and evaluated in M 5 generation. Gamma-ray dose of 200 Gy was most effective for improving the yield traits in both the genotypes as it brought out improvement in pods/plant, pod length and 100-seed wt. where as 400 Gy improved 100- seed wt. in only Sujata and 600 Gy improved pod length and seeds/pod only. Isolation of high yielding lines from the gamma-rays treated population of greengram proved that different doses of gamma rays induced improvement of different yield attributing characters in greengram. (author)

  20. Effect of gamma radiation dose and sensitizer on the physical properties of irradiated natural rubber latex

    International Nuclear Information System (INIS)

    Komgrit, R.; Thawat, C.; B, Tripob; Wirach, T.

    2009-07-01

    Full text: The vulcanization of natural rubber latex can be induced by gamma radiation, which enhances cross-linking within the rubber matrix. The purpose of this research is to investigate the effect of gamma radiation dose and sensitizers on the physical properties of irradiated natural rubber. Three sensitizers n-butyl acrylate (n-B A), tetrachloroethylene (C 2 Cl 4 ) and trichloromethane (CHCl 3 ) were mixed with natural rubber latex before irradiation with gamma ray dose varied from 14 to 22 kGy. Results showed that the mixture of three sensitizers with specific ratios effectively induced the cross-linking of natural rubber latex. The cross-linking ratio and improved physical properties increased with increasing gamma dose. Therefore, the mixture ratios of n-B A, C 2 Cl 4 and CHCl 3 have shown to be a critical parameter in the vulcanization of natural rubber latex by gamma radiation

  1. Gamma ray energy tracking in GRETINA

    Science.gov (United States)

    Lee, I. Y.

    2011-10-01

    The next generation of stable and exotic beam accelerators will provide physics opportunities to study nuclei farther away from the line of stability. However, these experiments will be more demanding on instrumentation performance. These come from the lower production rate for more exotic beams, worse beam impurities, and large beam velocity from the fragmentation and inverse reactions. Gamma-ray spectroscopy will be one of the most effective tools to study exotic nuclei. However, to fully exploit the physics reach provided by these new facilities, better gamma-ray detector will be needed. In the last 10 years, a new concept, gamma-ray energy tracking array, was developed. Tracking arrays will increase the detection sensitivity by factors of several hundred compared to current arrays used in nuclear physics research. Particularly, the capability of reconstructing the position of the interaction with millimeters resolution is needed to correct the Doppler broadening of gamma rays emitted from high velocity nuclei. GRETINA is a gamma-ray tracking array which uses 28 Ge crystals, each with 36 segments, to cover ¼ of the 4 π of the 4 π solid angle. The gamma ray tracking technique requires detailed pulse shape information from each of the segments. These pulses are digitized using 14-bit 100 MHz flash ADCs, and digital signal analysis algorithms implemented in the on-board FPGAs provides energy, time and selection of pulse traces. A digital trigger system, provided flexible trigger functions including a fast trigger output, and also allows complicated trigger decisions to be made up to 20 microseconds. Further analyzed, carried out in a computer cluster, determine the energy, time, and three-dimensional positions of all gamma-ray interactions in the array. This information is then utilized, together with the characteristics of Compton scattering and pair-production processes, to track the scattering sequences of the gamma rays. GRETINA construction is completed in

  2. Pathology of Serially Sacrificed Female B6C3F1 Mice Continuously Exposed to Very Low-Dose-Rate Gamma Rays.

    Science.gov (United States)

    Tanaka, I B; Komura, J; Tanaka, S

    2017-03-01

    We have previously reported on life span shortening as well as increased incidence rates in several neoplasms in B6C3F1 mice that were continuously exposed to 21 mGy/day of gamma rays for 400 days. To clarify whether the life shortening was due to early appearance of neoplasms (shortened latency) or increased promotion/progression, 8-week-old female specific-pathogen-free B6C3F1 mice were gamma-ray irradiated at a low dose rate of 20 mGy/day for 400 days. At 100 days postirradiation, 60-90 mice were sacrificed, and thereafter every 100 days alongside the age-matched nonirradiated controls, for 700 days. Additional groups were allowed to live out their natural life span. Pathological examination was performed on all mice to identify lesions, non-neoplastic and neoplastic, as well as to determine the cause of death. Body weights were significantly increased in irradiated mice from sacrifice days 200-500. Incidence rates for spontaneously occurring non-neoplastic lesions, such as adrenal subcapsular cell hyperplasia, fatty degeneration of the liver, atrophy and tubulostromal hyperplasia of the ovaries, were significantly increased in irradiated mice. Significantly increased incidence rates with no shortening of latency periods were observed in irradiated mice for malignant lymphomas, hepatocellular adenomas/carcinomas, bronchioloalveolar adenomas, harderian gland adenoma/adenocarcinoma. Shortened latencies with significantly increased incidence rates were observed for adrenal subcapsular cell adenomas and ovarian neoplasms (tubulostromal adenoma, granulosa cell tumors) in irradiated mice. Life span shortening in mice exposed to 20 mGy/day was mostly due to malignant lymphomas. Multiple primary neoplasms were significantly increased in mice exposed to 20 mGy/day from sacrifice days 400-700 and in the life span group. Our results confirm that continuous low-dose-rate gamma-ray irradiation of female B6C3F1 mice causes both cancer induction (shortened latency) and

  3. Relationship between accuracy and number of samples on statistical quantity and contour map of environmental gamma-ray dose rate. Example of random sampling

    International Nuclear Information System (INIS)

    Matsuda, Hideharu; Minato, Susumu

    2002-01-01

    The accuracy of statistical quantity like the mean value and contour map obtained by measurement of the environmental gamma-ray dose rate was evaluated by random sampling of 5 different model distribution maps made by the mean slope, -1.3, of power spectra calculated from the actually measured values. The values were derived from 58 natural gamma dose rate data reported worldwide ranging in the means of 10-100 Gy/h rates and 10 -3 -10 7 km 2 areas. The accuracy of the mean value was found around ±7% even for 60 or 80 samplings (the most frequent number) and the standard deviation had the accuracy less than 1/4-1/3 of the means. The correlation coefficient of the frequency distribution was found 0.860 or more for 200-400 samplings (the most frequent number) but of the contour map, 0.502-0.770. (K.H.)

  4. Dose distribution close to metal implants in Gamma Knife Radiosurgery: A Monte Carlo study

    International Nuclear Information System (INIS)

    Cheung, Joel Y.C.; Yu, K.N.; Chan, Josie F.K.; Ho, Robert T.K.; Yu, C.P.

    2003-01-01

    Materials with high atomic numbers favor the occurrence of the photoelectric effect when they are irradiated with gamma rays. Therefore, the photoelectric effects of metal implants within the target regions in Gamma Knife Radiosurgery are worth studying. In the present work, Monte Carlo simulations using EGS4 were employed to investigate the resulting dose enhancements. A dose enhancement as high as 10% was observed close to a platinum implant along the x and y axes, while no significant dose enhancements were observed for silver, stainless steel 301, and titanium ones. A dose enhancement as high as 20% was observed close to the platinum implant along the z axis at the superior position of the metal-phantom interface and was 10% higher for other metal implants

  5. Physics and astrophysics with gamma-ray telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Vandenbroucke, J. [Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)

    2012-08-15

    In the past few years gamma-ray astronomy has entered a golden age. A modern suite of telescopes is now scanning the sky over both hemispheres and over six orders of magnitude in energy. At {approx}TeV energies, only a handful of sources were known a decade ago, but the current generation of ground-based imaging atmospheric Cherenkov telescopes (H.E.S.S., MAGIC, and VERITAS) has increased this number to nearly one hundred. With a large field of view and duty cycle, the Tibet and Milagro air shower detectors have demonstrated the promise of the direct particle detection technique for TeV gamma rays. At {approx}GeV energies, the Fermi Gamma-ray Space Telescope has increased the number of known sources by nearly an order of magnitude in its first year of operation. New classes of sources that were previously theorized to be gamma-ray emitters have now been confirmed observationally. Moreover, there have been surprise discoveries of GeV gamma-ray emission from source classes for which no theory predicted it was possible. In addition to elucidating the processes of high-energy astrophysics, gamma-ray telescopes are making essential contributions to fundamental physics topics including quantum gravity, gravitational waves, and dark matter. I summarize the current census of astrophysical gamma-ray sources, highlight some recent discoveries relevant to fundamental physics, and describe the synergetic connections between gamma-ray and neutrino astronomy. This is a brief overview intended in particular for particle physicists and neutrino astronomers, based on a presentation at the Neutrino 2010 conference in Athens, Greece. I focus in particular on results from Fermi (which was launched soon after Neutrino 2008), and conclude with a description of the next generation of instruments, namely HAWC and the Cherenkov Telescope Array.

  6. Computer program SCAP-BR for gamma-ray streaming through multi-legged ducts

    International Nuclear Information System (INIS)

    Byoun, T.Y.; Babel, P.J.; Dajani, A.T.

    1977-01-01

    A computer program, SCAP-BR, has been developed at Burns and Roe for the gamma-ray streaming analysis through multi-legged ducts. SCAP-BR is a modified version of the single scattering code, SCAP, incorporating capabilities of handling multiple scattering and volumetric source geometries. It utilizes the point kernel integration method to calculate both the line-of-sight and scattered gamma dose rates by employing the ray tracing technique through complex shield geometries. The multiple scattering is handled by a repeated process of the single scatter method through each successive scatter region and collapsed pseudo source meshes constructed on the relative coordinate systems. The SCAP-BR results have been compared with experimental data for a Z-type (three-legged) concrete duct with a Co-60 source placed at the duct entrance point. The SCAP-BR dose rate predictions along the duct axis demonstrate an excellent agreement with the measured values

  7. X-Ray Spectral Characteristics of Ginga Gamma-Ray Bursts

    International Nuclear Information System (INIS)

    Strohmayer, T.E.; Fenimore, E.E.; Murakami, T.; Yoshida, A.

    1998-01-01

    We have investigated the spectral characteristics of a sample of bright gamma-ray bursts detected with the gamma-ray burst sensors aboard the satellite Ginga. This instrument employed a proportional and scintillation counter to provide sensitivity to photons in the 2 endash 400 keV region and as such provided a unique opportunity to characterize the largely unexplored X-ray properties of gamma-ray bursts. The photon spectra of the Ginga bursts are well described by a low-energy slope, a bend energy, and a high-energy slope. In the energy range where they can be compared, this result is consistent with burst spectral analyses obtained from the BATSE experiment aboard the Compton Gamma-Ray Observatory. However, below 20 keV we find evidence for a positive spectral number index in approximately 40% of our burst sample, with some evidence for a strong rolloff at lower energies in a few events. There is a correlation (Pearson's r = -0.62) between the low-energy slope and the bend energy. We find that the distribution of spectral bend energies extends below 10 keV. There has been some concern in cosmological models of gamma-ray bursts (GRBs) that the bend energy covers only a small dynamic range. Our result extends the observed dynamic range, and, since we observe bend energies down to the limit of our instrument, perhaps observations have not yet limited the range. The Ginga trigger range was virtually the same as that of BATSE, yet we find a different range of fit parameters. One possible explanation might be that GRBs have two break energies, one often in the 50 endash 500 keV range and the other near 5 keV. Both BATSE and Ginga fit with only a single break energy, so BATSE tends to find breaks near the center of its energy range, and we tend to find breaks in our energy range. The observed ratio of energy emitted in the X-rays relative to the gamma rays can be much larger than a few percent and, in fact, is sometimes larger than unity. The average for our 22 bursts

  8. Effect of low doses gamma radiation on the yield of tomato (local variety) grown in the open field (1990 and 1992)

    International Nuclear Information System (INIS)

    Al-Oudat, M.; Ayyoubi, Z.

    1994-04-01

    The stimulating effects of low doses of ionizing radiation on growth of various plants has been reported by many investigators. In 1970, the FAO/IAEA consultant group strongly recommended tomato as a test plant due to its economic importance and good adaptability to many climatic conditions. This work was carried out during the summer seasons of 1990 and 1992 in two sites in Damascus region. Samples of air dried seeds of tomato (Local variety) of previous season were irradiated by gamma-rays from a 137 Cs source using doses of 5, 10, 12.5, 15, 20, 30 and 40 Gy at dose rate of 9 Gy/min. Seeds were sown after 2 days from irradiation in complete randomized block design and replicated 4 times. The data revealed that gamma irradiation at interval doses of 5-12.5 Gy (in Khan-El-Sheeh) and 10-30 Gy (in Deir-El-Hajar) have stimulating effects on number of branches and early yield. The results of total yield as well as fruits number were significantly increased when doses of 10 and 12.5 Gy in Khan-El-Sheeh and 12.5-25 Gy in Deir-El-Hajar, were used. The percentage of increment varied from 12.6 to 18.2% in Khan-El-Sheeh and 14.3 to 30.9% in Deir-El-Hajar. In view of all above mentioned results, the use of radiation might be recommended as an easy tool for seed treatments to stimulate and increase the productivity of tomato. (author). 12 tabs

  9. Neutron/gamma dose separation by the multiple-ion-chamber technique

    International Nuclear Information System (INIS)

    Goetsch, S.J.

    1983-01-01

    Many mixed n/γ dosimetry systems rely on two dosimeters, one composed of a tissue-equivalent material and the other made from a non-hydrogenous material. The paired chamber technique works well in fields of neutron radiation nearly identical in spectral composition to that in which the dosimeters were calibrated. However, this technique is drastically compromised in phantom due to the degradation of the neutron spectrum. The three-dosimeter technique allows for the fall-off in neutron sensitivity of the two non-hydrogenous dosimeters. Precise and physically meaningful results were obtained with this technique with a D-T source in air and in phantom and with simultaneous D-T neutron and 60 Co gamma ray irradiation in air. The MORSE-CG coupled n/γ three-dimensional Monte Carlo code was employed to calculate neutron and gamma doses in a water phantom. Gamma doses calculated in phantom with this code were generally lower than corresponding ion chamber measurements. This can be explained by the departure of irradiation conditions from ideal narrow-beam geometry. 97 references

  10. Radon-222 related influence on ambient gamma dose.

    Science.gov (United States)

    Melintescu, A; Chambers, S D; Crawford, J; Williams, A G; Zorila, B; Galeriu, D

    2018-04-03

    Ambient gamma dose, radon, and rainfall have been monitored in southern Bucharest, Romania, from 2010 to 2016. The seasonal cycle of background ambient gamma dose peaked between July and October (100-105 nSv h -1 ), with minimum values in February (75-80 nSv h -1 ), the time of maximum snow cover. Based on 10 m a.g.l. radon concentrations, the ambient gamma dose increased by around 1 nSv h -1 for every 5 Bq m -3 increase in radon. Radon variability attributable to diurnal changes in atmospheric mixing contributed less than 15 nSv h -1 to the overall variability in ambient gamma dose, a factor of 4 more than synoptic timescale changes in air mass fetch. By contrast, precipitation-related enhancements of the ambient gamma dose were 15-80 nSv h -1 . To facilitate routine analysis, and account in part for occasional equipment failure, an automated method for identifying precipitation spikes in the ambient gamma dose was developed. Lastly, a simple model for predicting rainfall-related enhancement of the ambient gamma dose is tested against rainfall observations from events of contrasting duration and intensity. Results are also compared with those from previously published models of simple and complex formulation. Generally, the model performed very well. When simulations underestimated observations the absolute difference was typically less than the natural variability in ambient gamma dose arising from atmospheric mixing influences. Consequently, combined use of the automated event detection method and the simple model of this study could enable the ambient gamma dose "attention limit" (which indicates a potential radiological emergency) to be reduced from 200 to 400% above background to 25-50%. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Radiation transport in earth for neutron and gamma ray point sources above an air-ground interface

    International Nuclear Information System (INIS)

    Lillie, R.A.; Santoro, R.T.

    1979-03-01

    Two-dimensional discrete ordinates methods were used to calculate the instantaneous dose rate in silicon and neutron and gamma ray fluences as a function of depth in earth from point sources at various heights (1.0, 61.3, and 731.5 meters) above an air--ground interface. The radiation incident on the earth's surface was transported through an earth-only and an earth--concrete model containing 0.9 meters of borated concrete beginning 0.5 meters below the earth's surface to obtain fluence distributions to a depth of 3.0 meters. The inclusion of borated concrete did not significantly reduce the total instantaneous dose rate in silicon and, in all cases, the secondary gamma ray fluence and corresponding dose are substantially larger than the primary neutron fluence and corresponding dose for depths greater than 0.6 meter. 4 figures, 4 tables

  12. Radiation transport in earth for neutron and gamma-ray point sources above an air-ground interface

    International Nuclear Information System (INIS)

    Lillie, R.A.; Santoro, R.T.

    1980-01-01

    Two-dimensional discrete-ordinates methods have been used to calculate the instantaneous dose rate in silicon and neutron and gamma-ray fluences as a function of depth in earth from point sources at various heights (1.0, 61.3, and 731.5 m) above an air-ground interface. The radiation incident on the earth's surface was transported through an earth-only and an earth-concrete model containing 0.9 m of borated concrete beginning 0.5 m below the earth's surface to obtain fluence distributions to a depth of 3.0 m. The inclusion of borated concrete did not significantly reduce the total instantaneous dose rate in silicon, and in all cases, the secondary gamma-ray fluence and corresponding dose are substantially larger than the primary neutron fluence and corresponding dose for depths > 0.6 m

  13. Handbook on Mobile Gamma-ray Spectrometry

    DEFF Research Database (Denmark)

    Aage, Helle Karina; Korsbech, Uffe C C

    2003-01-01

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

  14. Swift: A gamma ray burst MIDEX

    International Nuclear Information System (INIS)

    Barthelmy, Scott

    2001-01-01

    Swift is a first of its kind multiwavelength transient observatory for gamma-ray burst astronomy. It has the optimum capabilities for the next breakthroughs in determining the origin of gamma-ray bursts and their afterglows as well as using bursts to probe the early Universe. Swift will also perform the first sensitive hard X-ray survey of the sky. The mission is being developed by an international collaboration and consists of three instruments, the Burst Alert Telescope (BAT), the X-ray Telescope (XRT), and the Ultraviolet and Optical Telescope (UVOT). The BAT, a wide-field gamma-ray detector, will detect ∼1 gamma-ray burst per day with a sensitivity 5 times that of BATSE. The sensitive narrow-field XRT and UVOT will be autonomously slewed to the burst location in 20 to 70 seconds to determine 0.3-5.0 arcsec positions and perform optical, UV, and X-ray spectrophotometry. On-board measurements of redshift will also be done for hundreds of bursts. Swift will incorporate superb, low-cost instruments using existing flight-spare hardware and designs. Strong education/public outreach and follow-up programs will help to engage the public and astronomical community. Swift has been selected by NASA for development and launch in late 2003

  15. Gamma-ray lasers or grasers

    International Nuclear Information System (INIS)

    Wilson, G.V.H.; George, E.P.; Hora, H.

    1976-01-01

    A method is described for controlling the emission and direction of gamma rays from excited nuclei contained in a sample source of suitable geometry having its major axis parallel to the proposed direction of gamma ray emission, comprising subjecting said sample source to thermal or dynamic polarization at temperatures approaching absolute zero in the presence of a strong magnetic field, and when a pulse of coherent gamma radiation is required along said major axis rotating the active nuclei through 90 0 by employing a short pulse of radio frequency oscillations in an auxilliary coil around the sample source

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

    International Nuclear Information System (INIS)

    Gabici, Stefano

    2011-01-01

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

  17. Librarian driven analysis of gamma ray spectra

    International Nuclear Information System (INIS)

    Kondrashov, V.; Petersone, I.

    2002-01-01

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

  18. Exfoliated graphite with graphene flakes as potential candidates for TL dosimeters at high gamma doses.

    Science.gov (United States)

    Ortiz-Morales, A; López-González, E; Rueda-Morales, G; Ortega-Cervantez, G; Ortiz-Lopez, J

    2018-06-06

    Graphite powder (GP) subjected to microwave radiation (MWG) results in exfoliation of graphite particles into few-layered graphene flakes (GF) intermixed with partially exfoliated graphite particles (PEG). Characterization of MWG by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Raman spectroscopy reveal few-layer GF with sizes ranging from 0.2 to 5 µm. Raman D, G, and 2D (G') bands characteristic of graphitic structures include evidence of the presence of bilayered graphene. The thermoluminescent (TL) dosimetric properties of MWG are evaluated and can be characterized as a gamma-ray sensitive and dose-resistant material with kinetic parameters (activation energy for the main peak located at 400 and 408 K is 0.69 and 0.72 eV) and threshold dose (~1 kGy and 5 kGy respectively). MWG is a low-Z material (Z eff = 6) with a wide linear range of TL dose-response (0.170-2.5 kGy) tested at doses in the 1-20 kGy range with promising results for applications in gamma-ray dosimetry. Results obtained in gamma irradiated MWG are compared with those obtained in graphite powder samples (GP) without microwave treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Neutron and gamma-ray transport experiments in liquid air

    International Nuclear Information System (INIS)

    Farley, W.E.

    1976-01-01

    Accurate estimates of neutron and gamma radiations from a nuclear explosion and their subsequent transport through the atmosphere are vital to nuclear-weapon employment studies: i.e., for determining safety radii for aircraft crews, casualty and collateral-damage risk radii for tactical weapons, and the kill range from a high-yield defensive burst for a maneuvering reentry vehicle. Radiation transport codes, such as the Laboratory's TARTNP, are used to calculate neutron and gamma fluences. Experiments have been performed to check and update these codes. Recently, a 1.3-m-radius liquid-air (21 percent oxygen) sphere, with a pulsed source of 14-MeV neutrons at its center, was used to measure the fluence and spectra of emerging neutrons and secondary gamma rays. Comparison of measured radiation dose with TARTNP showed agreement within 10 percent

  20. New stage in high-energy gamma-ray studies with GAMMA-400 after Fermi-LAT

    Directory of Open Access Journals (Sweden)

    Topchiev N.P.

    2017-01-01

    Full Text Available Fermi-LAT has made a significant contribution to the study of high-energy gamma-ray diffuse emission and the observations of 3000 discrete sources. However, one third of all gamma-ray sources (both galactic and extragalactic are unidentified, the data on the diffuse gamma-ray emission should be clarified, and signatures of dark matter particles in the high-energy gamma-ray range are not observed up to now. GAMMA-400, the currently developing gamma-ray telescope, will have angular (∼0.01∘ at 100 GeV and energy (∼1% at 100 GeV resolutions in the energy range of 10–1000 GeV which are better than Fermi-LAT (as well as ground gamma-ray telescopes by a factor of 5–10. It will observe some regions of the Universe (such as the Galactic Center, Fermi Bubbles, Crab, Cygnus, etc. in a highly elliptic orbit (without shading the telescope by the Earth continuously for a long time. It will allow us to identify many discrete sources, to clarify the structure of extended sources, to specify the data on the diffuse emission, and to resolve gamma rays from dark matter particles.

  1. Bright x-ray flares in gamma-ray burst afterglows.

    Science.gov (United States)

    Burrows, D N; Romano, P; Falcone, A; Kobayashi, S; Zhang, B; Moretti, A; O'brien, P T; Goad, M R; Campana, S; Page, K L; Angelini, L; Barthelmy, S; Beardmore, A P; Capalbi, M; Chincarini, G; Cummings, J; Cusumano, G; Fox, D; Giommi, P; Hill, J E; Kennea, J A; Krimm, H; Mangano, V; Marshall, F; Mészáros, P; Morris, D C; Nousek, J A; Osborne, J P; Pagani, C; Perri, M; Tagliaferri, G; Wells, A A; Woosley, S; Gehrels, N

    2005-09-16

    Gamma-ray burst (GRB) afterglows have provided important clues to the nature of these massive explosive events, providing direct information on the nearby environment and indirect information on the central engine that powers the burst. We report the discovery of two bright x-ray flares in GRB afterglows, including a giant flare comparable in total energy to the burst itself, each peaking minutes after the burst. These strong, rapid x-ray flares imply that the central engines of the bursts have long periods of activity, with strong internal shocks continuing for hundreds of seconds after the gamma-ray emission has ended.

  2. NO CORRELATION BETWEEN HOST GALAXY METALLICITY AND GAMMA-RAY ENERGY RELEASE FOR LONG-DURATION GAMMA-RAY BURSTS

    International Nuclear Information System (INIS)

    Levesque, Emily M.; Kewley, Lisa J.; Soderberg, Alicia M.; Berger, Edo

    2010-01-01

    We compare the redshifts, host galaxy metallicities, and isotropic (E γ,iso ) and beaming-corrected (E γ ) gamma-ray energy release of 16 long-duration gamma-ray bursts (LGRBs) at z γ,iso , or E γ . These results are at odds with previous theoretical and observational predictions of an inverse correlation between gamma-ray energy release and host metallicity, as well as the standard predictions of metallicity-driven wind effects in stellar evolutionary models. We consider the implications that these results have for LGRB progenitor scenarios, and discuss our current understanding of the role that metallicity plays in the production of LGRBs.

  3. Carotenoid content of husk tomato under the influence of growth regulators and gamma rays

    International Nuclear Information System (INIS)

    Raghava, R.P.; Raghava, Nisha

    1990-01-01

    The present studies were conducted to study the effect of growth regulators and gamma rays on carotenoid content in husk tomato (Physalis peruviana L. and P. angulata L.). Results indicated that carotenoid content (in fruits) increased in all the treatments (except 200 and 500 ppm coumarin in case of P. peruviana and 100, 200 and 500 ppm coumarin in case of P. angulata). It is concluded that low doses of gamma rays may show stimulatory effect on carotenoid content in fruits of husk tomato. (author). 10 refs., 1 tab

  4. Gamma ray camera

    International Nuclear Information System (INIS)

    Wang, S.-H.; Robbins, C.D.

    1979-01-01

    An Anger gamma ray camera is improved by the substitution of a gamma ray sensitive, proximity type image intensifier tube for the scintillator screen in the Anger camera. The image intensifier tube has a negatively charged flat scintillator screen, a flat photocathode layer, and a grounded, flat output phosphor display screen, all of which have the same dimension to maintain unit image magnification; all components are contained within a grounded metallic tube, with a metallic, inwardly curved input window between the scintillator screen and a collimator. The display screen can be viewed by an array of photomultipliers or solid state detectors. There are two photocathodes and two phosphor screens to give a two stage intensification, the two stages being optically coupled by a light guide. (author)

  5. Bacteriostatic activity of various antibiotics after gamma-ray irradiation

    International Nuclear Information System (INIS)

    Fleurette, J.; Madier, S.; Transy, M.J.

    1975-01-01

    The purpose of the work described was to discover whether the antibiotics used in medicine can be sterilized by gamma rays; in this preliminary study, only the antimicrobic activity - the principal criterion for this type of medicament - was evaluated. Thirty-three products belonging to the various families of antibacterial and antifungic antibiotics were studied. The substances were irradiated in the dry state and in an aqueous solution, using a caesium-137 irradiator. The antibacterial and antifungic activity before and after irradiation was investigated by the method of diffusion in gelose. When irradiated in the dry state, 14 antibiotics preserve normal activity up to a dose of 10 Mrad; at doses between 5 and 10 Mrad, 15 other antibiotics are subject to a variable, but moderate, loss activity; and four register a slight loss of activity at a dose of 2.5 Mrad. In an aqueous solution all but two of the antibiotics suffer total loss of activity at a dose of 2.5 Mrad. As most commercial antibiotics are supplied in the dry state, gamma irradiation may be a useful sterilization process. However, preparations such as eye lotions, suspensions, ointments, etc. should be excepted

  6. Estimation of the radiation strength, dose equivalent and mean gamma-ray energy form p+ sup 2 sup 3 sup 8 U fission products

    CERN Document Server

    Kawakami, H

    2003-01-01

    On 100 isobars from 72 to 171 mass number, the radiation strength, dose equivalent and mean gamma-ray energy from p+ sup 2 sup 3 sup 8 U fission products at Tandem accelerator facility were estimated on the basis of data of proton induced fission mass yield by T. Tsukada. In order to control radiation, the decay curves of radiation of each mass after irradiation were estimated and illustrated. These calculation results showed 1) the peak of p+ sup 2 sup 3 sup 8 U fission products is 101 and 133 mass number. 2) gamma-ray strength of target ion source immediately after irradiation is 3.12x10 sup 1 sup 1 (Radiation/s) when it repeated 4 cycles of UC sub 2 (2.6 g/cm sup 2) target radiated by 30 MeV and 3 mu A proton for 5 days and then cooled for 2 days. It decreased to 3.85x10 sup 1 sup 0 and 6.7x10 sup 9 (Radiation/s) after one day and two weeks cooling, respectively. 3) Total dose equivalent is 3.8x10 sup 4 (mu S/h) at 1 m distance without shield. 4) There are no problems on control the following isobars, beca...

  7. Gamma ray, EMS and sodium azide induced effectiveness and efficiency of chlorophyll mutations in basmati rice (Oryza sativa L.)

    International Nuclear Information System (INIS)

    Singh, Sanjeev; Singh, J.; Singh, R.K.

    2001-01-01

    The effectiveness and efficiency of gamma ray, EMS, sodium azide alone or in combination in relation to chlorophyll mutations in two varieties of Basmati rice (Oryza sativa L.) in M 2 generation were studied. The chlorophyll mutations were induced by all the doses of mutagens alone or in combination relatively at a fair frequency in both the varieties in M 2 generation. In general, it was found that combination treatments of gamma rays and EMS were observed to be more efficient in Taraori Basmati, while EMS alone and combination treatment of gamma rays and EMS were more efficient in Pusa Basmati 1 on sterility and growth injury basis both. Sodium azide at 0.5 mM was found as the most effective dose in both Taraori Basmati and Pusa Basmati 1 cultivars. (author)

  8. Polarization of the prompt gamma-ray emission from the gamma-ray burst of 6 December 2002.

    Science.gov (United States)

    Coburn, Wayne; Boggs, Steven E

    2003-05-22

    Observations of the afterglows of gamma-ray bursts (GRBs) have revealed that they lie at cosmological distances, and so correspond to the release of an enormous amount of energy. The nature of the central engine that powers these events and the prompt gamma-ray emission mechanism itself remain enigmatic because, once a relativistic fireball is created, the physics of the afterglow is insensitive to the nature of the progenitor. Here we report the discovery of linear polarization in the prompt gamma-ray emission from GRB021206, which indicates that it is synchrotron emission from relativistic electrons in a strong magnetic field. The polarization is at the theoretical maximum, which requires a uniform, large-scale magnetic field over the gamma-ray emission region. A large-scale magnetic field constrains possible progenitors to those either having or producing organized fields. We suggest that the large magnetic energy densities in the progenitor environment (comparable to the kinetic energy densities of the fireball), combined with the large-scale structure of the field, indicate that magnetic fields drive the GRB explosion.

  9. Radon survey and soil gamma doses in primary schools of Batman, Turkey.

    Science.gov (United States)

    Damla, Nevzat; Aldemir, Kamuran

    2014-06-01

    A survey was conducted to evaluate levels of indoor radon and gamma doses in 42 primary schools located in Batman, southeastern Anatolia, Turkey. Indoor radon measurements were carried out using CR-39 solid-state nuclear track detector-based radon dosimeters. The overall mean annual (222)Rn activity in the surveyed area was found to be 49 Bq m(-3) (equivalent to an annual effective dose of 0.25 mSv). However, in one of the districts (Besiri) the maximum radon value turned out to be 307 Bq m(-3). The estimated annual effective doses are less than the recommended action level (3-10 mSv). It is found that the radon concentration decreases with increasing floor number. The concentrations of natural and artificial radioisotopes were determined using gamma-ray spectroscopy for soil samples collected in close vicinity of the studied schools. The mean gamma activity concentrations in the soil samples were 31, 25, 329 and 12 Bq kg(-1) for (226)Ra, (232)Th, (40)K and (137)Cs, respectively. The radiological parameters such as the absorbed dose rate in air and the annual effective dose equivalent were calculated. These radiological parameters were evaluated and compared with the internationally recommended values.

  10. The effects of Co60 gamma rays on the absorption of salicylic natrium orally given to white rats

    International Nuclear Information System (INIS)

    Wiharto, Kunto; Kamal, Zainul; Mulyanto; Muryono, H.

    1982-01-01

    The effects of Co 60 gamma rays on the absorption of salicylic natrium orally taken by white rats after being irradiated were studied. Patients treated with radiation used to be given analgesic drugs to elicit pain. Effects of radiation on the physiology of gastrointestinal tracts of such patients are to be studied. Based on this perception some white rats were irradiated with Co 60 gamma rays at the cumulative doses of 500, 750, and 1000 rads which were fractionated to 5 daily doses of 100, 150, and 200 rads. Salicylate concentration in the rat's blood was measured with spectrophotometer. It was found that the greater the radiation dose was given, the less salicylic natrium was absorbed and at a certain dose saturation point happened. (RUW)

  11. Batteryless {gamma}-Ray Dosimeter; Dosimetre de rayons {gamma}, sans batteries; {gamma}-dozimetr bez batarei; Dosimetro a rayos {gamma} sin bateria

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Bernhard [National Institute of Technology, Rio de Janeiro (Brazil)

    1960-06-15

    The Compton current produced by X-rays and {gamma}-rays in the 0.3 to 3 MeV range is proportional to the radiant energy flux. Therefore the intensity of the current can be used as a measure of radiation dose. The present paper describes a radiation receiver and electrical measuring system suitable for Compton current measurements and results obtained with this device under irradiation from a 2000 curie Co{sup 60} source. (author) [French] Le courant de Compton produit par des rayons X et {gamma} dans le domaine d'energies compris entre 0,3 et 3 MeV est proportionnel au flux d'energie rayonnante. C'est pourquoi l'intensite du courant peut servir de mesure de la dose de rayonnements. Le memoire decrit un ensemble, appareil recepteur de rayonnements et appareil de mesure electrique, permettant de mesurer le courant de Compton et il expose les resultats obtenus, au moyen de ce dispositif, sous irradiation par une source de Co{sup 60} de 2000 curies. (author) [Spanish] La corriente de Compton producida por rayos X y rayos {gamma} de energia comprendida entre 0,3 y 3 MeV es proporcional al flujo de energia radiante. Por consiguiente, la intensidad de la corriente puede servir para medir la dosis de radiacion. En este trabajo se describen un receptor de radiaciones y un sistema de medicion electrica apropiados para determinar la intensidad de la corriente de Compton, asi como los resultados obtenidos mediante este dis- positivo cuando se irradia con una fuente de Co{sup 60} de 2000 curies. (author) [Russian] Komptonovskij potok, obrazuemyj rentgenovskim i luchami i {gamma}-luchami v predelakh ot 0,3 do 3 mehv, proportsionale n potoku luchistoj ehnergii. Poehtomu intensivnost' potoka mozhet byt' ispol'zovana dlya izmereniya dozy radiatsii. V nastoyashchem dokumente opisyvayutsya radiatsionny j priemnik i ehlektricheskaya izmeritel'naya sistema, prigodnye dlya izmerenij s pomoshch'yu komptonovskog o potoka, i rezul'taty, poluchennye s pomoshch'yu ehtogo ustrojstva v khode

  12. X-Ray and Gamma-Ray Radiation Detector

    DEFF Research Database (Denmark)

    2015-01-01

    Disclosed is a semiconductor radiation detector for detecting X-ray and / or gamma-ray radiation. The detector comprises a converter element for converting incident X-ray and gamma-ray photons into electron-hole pairs, at least one cathode, a plurality of detector electrodes arranged with a pitch...... (P) along a first axis, a plurality of drift electrodes, a readout circuitry being configured to read out signals from the plurality of detector electrodes and a processing unit connected to the readout circuitry and being configured to detect an event in the converter element. The readout circuitry...... is further configured to read out signals from the plurality of drift electrodes, and the processing unit is further configured to estimate a location of the event along the first axis by processing signals obtained from both the detector electrodes and the drift electrodes, the location of the event along...

  13. Crystal growth and thermoluminescence response of NaZr{sub 2}(PO{sub 4}){sub 3} at high gamma radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Ordóñez-Regil, E., E-mail: eduardo.ordonez@inin.gob.mx [Depto. de Química, Gerencia de Ciencias Básicas, Instituto Nacional de Investigaciones Nucleares, AP 18-1027, CP 11801 México D.F. (Mexico); Contreras-Ramírez, A., E-mail: aida.contreras@inin.gob.mx [Depto. de Química, Gerencia de Ciencias Básicas, Instituto Nacional de Investigaciones Nucleares, AP 18-1027, CP 11801 México D.F. (Mexico); Depto. de Tecnología de Materiales, Gerencia de Ciencias Aplicadas, Instituto Nacional de Investigaciones Nucleares, AP 18-1027, CP 11801 México D.F. (Mexico); Facultad de Ciencias, Universidad Autónoma del Estado de México, Unidad Académica el Cerrillo, Piedras Blancas, AP 2-139, CP 50000 Toluca Estado de México (Mexico); Fernández-Valverde, S.M., E-mail: suilma.fernandez@inin.gob.mx [Depto. de Química, Gerencia de Ciencias Básicas, Instituto Nacional de Investigaciones Nucleares, AP 18-1027, CP 11801 México D.F. (Mexico); González-Martínez, P.R., E-mail: pedro.gonzalez@inin.gob.mx [Depto. de Física, Gerencia de Ciencias Básicas, Instituto Nacional de Investigaciones Nucleares, AP 18-1027, CP 11801 México D.F. (Mexico); Carrasco-Ábrego, H., E-mail: hector.carrasco@inin.gob.mx [Depto. Aceleradores, Gerencia de Ciencias Ambientales, Instituto Nacional de Investigaciones Nucleares, AP 18-1027, CP 11801 México D.F. (Mexico)

    2013-11-15

    Graphical abstract: -- Highlights: •NaZr{sub 2}(PO{sub 4}){sub 3} exposed to gamma doses of 10, 30 and 50 MGy. •Gamma radiation produced growth of the crystal size of the NZP. •Morphology changes were reversible by heating. •Linear relationship between the thermoluminescence and the applied gamma dose. •This property could be useful for high-level gamma dosimetry. -- Abstract: This work describes the synthesis and characterization of NaZr{sub 2}(PO{sub 4}){sub 3}. The stability of this material under high doses of gamma radiation was investigated in the range of 10–50 MGy. Samples of unaltered and gamma irradiated NaZr{sub 2}(PO{sub 4}){sub 3} were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and thermoluminescence. The results showed that while functional groups were not affected by the gamma irradiation, morphology changes were observed with increasing doses of gamma irradiation. The morphology of the non-irradiated compound is agglomerated flakes; however, irradiation at 10 MGy splits the flakes inducing the formation of well-defined cubes. Gamma irradiation induced the crystal size of the NaZr{sub 2}(PO{sub 4}){sub 3} to grow. The heat treatment (973 K) of samples irradiated at 50 MGy resulted in the recovery of the original morphology. Furthermore, the thermoluminescence analysis of the irradiated compound is reported.

  14. A study on gamma rays from electrochemical cells

    International Nuclear Information System (INIS)

    Shin, Seung Ai

    1993-01-01

    The energies and intensities of gamma rays emitted from 3 cells with Pd-cathodes of φ 1mm x 10mm, φ 2mm x 20mm, φ 1mm x 10mm were determined using HPGe-detector system and compared with Pd-neutron capture model. Very strong gamma rays of 512keC, 622keC, 1051keC and 8 more important ones were found to be identical with characteristic gamma rays of 106 Pd and 109 Pd. It is likely that the neutron capture reaction, A PD(n, γ) A+1 Pd, occurred in the cell and the neutrons came from the fusion reaction of two deutrons. It is necessary, however, to retest the model since another strong 84keV-gamma rays do not belong to any A+1 Pd-gamma spectra and two important 106 Pd-gamma rays 717keV, 1046KeV were not detected. Total amount of emitted gamma rays was large when the size of the Pd-cathod was large. Its depedence on the time of measurement and the preheating period did not have any regularities. Thus the replication is not an easy thing. (Author)

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

    International Nuclear Information System (INIS)

    Martini, Gisela A.; Pusceddu, Fabio H.; Rogero, Sizue O.; Rogero, Jose Roberto

    2013-01-01

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

  16. Effect of low doses gamma irradiation on the yield of cucumber grown under field and protected conditions

    International Nuclear Information System (INIS)

    Al-Oudat, M.; Ayyoubi, Z.; Razzouk, A.K.

    1994-08-01

    Presowing seed irradiation has been reported as a useful application of radiation in agriculture to stimulate growth and increase the yield of certain field crops. To the best of our knowledge the feasibility of this treatment has not yet been tested on cucumber in Syria. Our experiments were carried out in field and greenhouse conditions. Two experiments were under field conditions, the first at Der-El-Hajar (Unfertile soil with high mean temperature), and the second at Khan-El-Sheeh (fertile soil with lower mean temperature), in these two experiments local variety was used. The third experiment was under greenhouse condition using two varieties, F1 Hybrid Taha and Sahara. Samples of air dried seeds of previous season were irradiated by gamma rays from a 60 Co source using doses of 2, 3, 4, 5, 7.5, 10 and 15 Gy at dose rate of 0.8 Gy/min. Seeds were planted after two days from irradiation and replicated 4 times. The data revealed that gamma irradiation at interval doses of 3-7.5 Gy led to increase the number of leaves and plant height. The radiation treatment had stimulating effects on earliness especially for doses of 4-7.5 Gy in Khan-El-Sheeh (14-31%) and 7.5 Gy in Der-El-Hajar (28%). In greenhouse dose of 2-4 Gy and 2-7.5 Gy stimulate the earliness by 12-36% and 11-18% for Sahara and Taha varieties respectively. The results of total yield (as well as fruits number) were significantly increased when doses of 7.5 Gy in Der-El-Hajar (25%) and 4 and 5 Gy in Khan-El-Sheeh (28-30%). The optimum doses in greenhouse condition ranged between 32-4 Gy for Taha var. and 4-5 Gy for Sahara var., and the percentage of increment was 19 and 16% respectively. In view of all above mentioned results, the use of radiation might be recommended as easy tool for seed treatment to stimulate earliness and increase productivity of cucumber. (author). 17 refs., 23 tabs

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

    Science.gov (United States)

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

    1991-01-01

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

  18. Gamma-ray detection and Compton camera image reconstruction with application to hadron therapy

    International Nuclear Information System (INIS)

    Frandes, M.

    2010-09-01

    A novel technique for radiotherapy - hadron therapy - irradiates tumors using a beam of protons or carbon ions. Hadron therapy is an effective technique for cancer treatment, since it enables accurate dose deposition due to the existence of a Bragg peak at the end of particles range. Precise knowledge of the fall-off position of the dose with millimeters accuracy is critical since hadron therapy proved its efficiency in case of tumors which are deep-seated, close to vital organs, or radio-resistant. A major challenge for hadron therapy is the quality assurance of dose delivery during irradiation. Current systems applying positron emission tomography (PET) technologies exploit gamma rays from the annihilation of positrons emitted during the beta decay of radioactive isotopes. However, the generated PET images allow only post-therapy information about the deposed dose. In addition, they are not in direct coincidence with the Bragg peak. A solution is to image the complete spectrum of the emitted gamma rays, including nuclear gamma rays emitted by inelastic interactions of hadrons to generated nuclei. This emission is isotropic, and has a spectrum ranging from 100 keV up to 20 MeV. However, the measurement of these energetic gamma rays from nuclear reactions exceeds the capability of all existing medical imaging systems. An advanced Compton scattering detection method with electron tracking capability is proposed, and modeled to reconstruct the high-energy gamma-ray events. This Compton detection technique was initially developed to observe gamma rays for astrophysical purposes. A device illustrating the method was designed and adapted to Hadron Therapy Imaging (HTI). It consists of two main sub-systems: a tracker where Compton recoiled electrons are measured, and a calorimeter where the scattered gamma rays are absorbed via the photoelectric effect. Considering a hadron therapy scenario, the analysis of generated data was performed, passing trough the complete

  19. Morphological changes induced by different doses of gamma irradiation in garlic sprouts

    Energy Technology Data Exchange (ETDEWEB)

    Pellegrini, C.N. E-mail: pellegri@criba.edu.ar; Croci, C.A.; Orioli, G.A

    2000-03-01

    The objective of this work was to evaluate the effects of different doses of gamma rays applied in dormancy and post-dormancy on garlic bulbs in relation with some morphophysiological parameters. High (commercial) doses cause the complete inhibition of sprouting and mitosis (due to nuclear aberrations). Relatively low doses show no effects on bulbs but doses of 10 Gy applied in post-dormancy reduce sprouting and stop mitosis. This inhibition becomes noticeable from 150 days post-harvest onwards. Exogenous growth regulators can reverse these effects. Results may reinforce the good practice of radioinhibition processes in garlic. (author)0.

  20. An X-ray perspective on a gamma-ray mission

    DEFF Research Database (Denmark)

    Lund, Niels

    2003-01-01

    The most recent astrophysics mission of ESA is INTEGRAL, a mission dedicated to gamma-ray astronomy (Winkler et al. 2003). INTEGRAL carries two gamma-ray instruments: the imager, IBIS, and the spectrometer, SPI, and in addition an optical monitor, OMC, and an X-ray monitor, JEM-X. INTEGRAL is an ...... is an observatory mission with 70% of the observation time available to the general astronomical community through a peer-reviewed selection process. This paper describes the INTEGRAL mission primarily as seen from the JEM-X perspective....

  1. Constraints on the galactic distribution of cosmic rays from the COS-B gamma-ray data

    International Nuclear Information System (INIS)

    1985-08-01

    The velocity information of the HI and CO observations is used as a distance indicator to ascertain the spatial distribution of the interstellar gas. Using this distance information, the galacto-centric distribution of the gamma-ray emissivity (the production rate per H atom) is determined for three gamma-ray energy ranges from a correlation study of the gamma-ray intensity maps and the gas-tracer maps for selected galacto-centric distance intervals, taking into account the expected IC contribution and pointlike gamma-ray sources. On the assumption that unresolved gamma-ray point sources do not contribute significantly to the observed gamma-ray emission, the gamma-ray emissivity is proportional to the Cosmic ray density and, more specifically, the energy dependence can be used to study separately the distribution of Cosmic ray electrons and nuclei: whereas the emission for the 300 MeV - 5 GeV range is dominated by π 0 -decay, the 70 MeV - 150 MeV range has a large electron bremsstrahlung contribution

  2. Gamma dosimetry with CR-39 etch track detector

    International Nuclear Information System (INIS)

    Matiullah; Dogar, A.H.; Ahmad, N.; Amin, M.; Kudo, Katsuhisa

    1999-01-01

    To preserve and improve the safety of food for commercial purposes, it is exposed to high gamma-ray doses. The gamma-ray doses used for this purpose range from 0.15 kGy to 50 kGy. At such high doses, the etching characteristics of CR-39 are severely affected. This property, therefore, can be used to develop a CR-39-based gamma dosimeter. In this context, systematic studies were carried out and the bulk etching rate was determined as a function of gamma-ray dose using different methods. (author)

  3. Effect of Addition of Soybean Oil and Gamma-Ray Cross-linking on the Nanoporous HDPE Membrane

    Directory of Open Access Journals (Sweden)

    Jong-Seok Park

    2012-01-01

    Full Text Available A nanoporous high-density polyethylene (HDPE membrane was prepared by a wet process. Soybean oil and dibutyl phthalate (DBP were premixed as codiluents, and gamma-rays were used for the cross-linking of HDPE. The pore volume of the nanoporous HDPE membranes with soybean oil was affected by the extracted amount of oil. The tensile strength of the membrane improved with an increasing absorbed dose up to 60 kGy, but decreased at 80 kGy due to severe degradation. The ionic conductivity of the nanoporous HDPE membrane did not really change with an increasing absorbed dose because the pores had already been formed before the gamma-ray radiation. Finally, the electrochemical stability of the HDPE membrane increased when the absorbed dose increased up to 60 kGy.

  4. The role of {sup 60}Co gamma-ray irradiation on the interface states and series resistance in MIS structures

    Energy Technology Data Exchange (ETDEWEB)

    Tascioglu, Ilke [Department of Physics, Faculty of Science and Arts, Gazi University, 06500 Ankara (Turkey); Tataroglu, Adem, E-mail: ademt@gazi.edu.t [Department of Physics, Faculty of Science and Arts, Gazi University, 06500 Ankara (Turkey); Ozbay, Akif; Altindal, Semsettin [Department of Physics, Faculty of Science and Arts, Gazi University, 06500 Ankara (Turkey)

    2010-04-15

    The effect of gamma-ray exposure on the metal-insulator-semiconductor (MIS) structures has been investigated using the electrical characteristics at room temperature. The MIS structures are irradiated with {sup 60}Co gamma-ray source. The energy distribution of interface states was determined from the forward bias I-V characteristics by taking into account the bias dependence of the effective barrier height and ideality factor. The value of series resistance decreases with increasing dose. Experimental results confirmed that gamma-ray irradiation have a significant effect on electrical characteristics of MIS structures.

  5. Effect of spirit irradiation with 60Co gamma-rays

    International Nuclear Information System (INIS)

    Gwardys, S.

    1975-01-01

    A few sorts of spirit were irradiated with a dose of 1 or 5 Mrad of 60 Co gamma-rays. Then the chemical composition of spirits was investigated. It was found that as a result of irradiation the content of acids, esters, acetal aldehydes and methanol increases, while the strength of higher alcohols decreases slightly. The changes of compounds content in particular spirits are dependent on radiation doses and chemical composition before irradiation. It was also discovered that spirit irradiation causes decrease or even disappearance of characteristic - for given spirits - maxima of UV absorption. (Z.M.)

  6. THERMAL X-RAY EMISSION FROM THE SHOCKED STELLAR WIND OF PULSAR GAMMA-RAY BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Zabalza, V.; Paredes, J. M. [Departament d' Astronomia i Meteorologia, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona (IEEC-UB), Marti i Franques 1, E08028 Barcelona (Spain); Bosch-Ramon, V., E-mail: vzabalza@am.ub.es [Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland)

    2011-12-10

    Gamma-ray-loud X-ray binaries are binary systems that show non-thermal broadband emission from radio to gamma rays. If the system comprises a massive star and a young non-accreting pulsar, their winds will collide producing broadband non-thermal emission, most likely originated in the shocked pulsar wind. Thermal X-ray emission is expected from the shocked stellar wind, but until now it has neither been detected nor studied in the context of gamma-ray binaries. We present a semi-analytic model of the thermal X-ray emission from the shocked stellar wind in pulsar gamma-ray binaries, and find that the thermal X-ray emission increases monotonically with the pulsar spin-down luminosity, reaching luminosities of the order of 10{sup 33} erg s{sup -1}. The lack of thermal features in the X-ray spectrum of gamma-ray binaries can then be used to constrain the properties of the pulsar and stellar winds. By fitting the observed X-ray spectra of gamma-ray binaries with a source model composed of an absorbed non-thermal power law and the computed thermal X-ray emission, we are able to derive upper limits on the spin-down luminosity of the putative pulsar. We applied this method to LS 5039, the only gamma-ray binary with a radial, powerful wind, and obtain an upper limit on the pulsar spin-down luminosity of {approx}6 Multiplication-Sign 10{sup 36} erg s{sup -1}. Given the energetic constraints from its high-energy gamma-ray emission, a non-thermal to spin-down luminosity ratio very close to unity may be required.

  7. Protective and Therapeutic Role of Low Dose Gamma Radiation on Streptozotocin Induced Diabetes in Rats

    International Nuclear Information System (INIS)

    Mansour, H.H.; Hafez, H.F.; Shouman, S.A.

    2011-01-01

    Diabetes mellitus is a multi-factorial disease which is characterized by vascular and renal complication. This study was initiated to investigate the protective and the therapeutic effect of low dose of gamma radiation (LDR) on diabetic complications. A total of 30 adult male rats were divided into 5 groups: Group I: served as control and injected intraperitoneally with 0.2 ml of 0.1 mol/l citrate buffer (ph 4.5), group II: rats became diabetic via intraperitoneal injection with 60 mg/kg streptozotocin (STZ) dissolved in 0.2 ml of 0.1 mol/l citrate buffer (ph 4.5), group III irradiated rats (IRR): submitted to fractionated dose of whole body gamma rays; 0.25 Gy for 2 consecutive days (whole dose 0.5 Gy), group IV diabetic irradiated rats (STZ + IRR): rats became diabetic as group II then four weeks after diabetes induction (day 28), rats were submitted to 2 fractions of whole body gamma rays as in group III, and group V irradiated diabetic rats (IRR + STZ): rats were injected intraperitoneally with 0.2 ml of 0.1 mol/l citrate buffer then submitted to whole body gamma rays; 0.25 Gy for 2 consecutive days then one hour after the last IRR dose, rats were made diabetic as group II. In pre and post-irradiation of STZ rats, significant changes were observed in serum lipid profiles, hepatic and cardiac serum enzymes. Significant decrease in hepatic and cardiac malondialdehyde (MDA) and total nitrate/nitrite (NO(x)) levels, and significant increase in superoxide dismutase (SOD) and glutathione (GSH) levels were observed as compared to diabetic group. The study suggests that LDR may provide useful protective and therapeutic option in the reversal of oxidative stress induced in diabetic rats

  8. THE ORIGIN OF GAMMA RAYS FROM GLOBULAR CLUSTERS

    International Nuclear Information System (INIS)

    Cheng, K. S.; Chernyshov, D. O.; Dogiel, V. A.; Hui, C. Y.; Kong, A. K. H.

    2010-01-01

    Fermi has detected gamma-ray emission from eight globular clusters (GCs). It is commonly believed that the energy sources of these gamma rays are millisecond pulsars (MSPs) inside GCs. Also it has been standard to explain the spectra of most Fermi Large Area Telescope pulsars including MSPs resulting from the curvature radiation (CR) of relativistic electrons/positrons inside the pulsar magnetosphere. Therefore, gamma rays from GCs are expected to be the collection of CR from all MSPs inside the clusters. However, the angular resolution is not high enough to pinpoint the nature of the emission. In this paper, we calculate the gamma rays produced by the inverse Compton (IC) scattering between relativistic electrons/positrons in the pulsar wind of MSPs in the GCs and background soft photons including cosmic microwave/relic photons, background star lights in the clusters, the galactic infrared photons, and the galactic star lights. We show that the gamma-ray spectrum from 47 Tucanae can be explained equally well by upward scattering of either the relic photons, the galactic infrared photons, or the galactic star lights, whereas the gamma-ray spectra from the other seven GCs are best fitted by the upward scattering of either the galactic infrared photons or the galactic star lights. We also find that the observed gamma-ray luminosity is correlated better with the combined factor of the encounter rate and the background soft photon energy density. Therefore, the IC scattering may also contribute to the observed gamma-ray emission from GCs detected by Fermi in addition to the standard CR process. Furthermore, we find that the emission region of high-energy photons from GCs produced by the IC scattering is substantially larger than the cores of GCs with a radius >10 pc. The diffuse radio and X-rays emitted from GCs can also be produced by the synchrotron radiation and IC scattering, respectively. We suggest that future observations including radio, X-rays, and gamma rays

  9. Response of radiation monitoring labels to gamma rays and electrons

    DEFF Research Database (Denmark)

    Rahim, F. Abdel; Miller, Arne; McLaughlin, W.L.

    1985-01-01

    or location has been irradiated to high doses. Among labels available worldwide, a few are suitable for indicating absorbed dose regions of slightly less than 104 Gy (monitoring high dose ranges (i.e., sterilization dose levels of > 104 Gy or > 1 Mrad), and in some cases......, and differences in dose rate and radiation type (gamma rays and electron beams) were made on 15 kinds of labels. The results show that, for many types of indicators, diverse effects may give misleading conclusions unless countermeasures are taken. For example, some of the most commonly used labels, which contain...... permit somewhat more precise discrimination of dose levels, and may sometimes be useful for monitoring differences in local dose distributions or area monitoring of radiation damage probabilities around particle accelerators or large radionuclide sources....

  10. The early X-ray afterglows of optically bright and dark Gamma-Ray Bursts

    OpenAIRE

    Lin, Yi-Qing

    2006-01-01

    A systematical study on the early X-ray afterglows of both optically bright and dark gamma-ray bursts (B-GRBs and D-GRBs) observed by Swift has been presented. Our sample includes 25 GRBs. Among them 13 are B-GRBs and 12 are D-GRBs. Our results show that the distributions of the X-ray afterglow fluxes ($F_{X}$), the gamma-ray fluxes ($S_{\\gamma}$), and the ratio ($R_{\\gamma, X}$) for both the D-GRBs and B-GRBs are similar. The differences of these distributions for the two kinds of GRBs shoul...

  11. Evaluation of absorbed dose-distribution in the X-ray or gamma-irradiator for blood products

    International Nuclear Information System (INIS)

    Moriyama, Satoshi; Kurihara, Katsuhiko; Yokokawa, Nobuhiko; Satake, Masahiro; Juji, Takeo

    2001-01-01

    Irradiation of blood products abrogates the proliferation of lymphocytes present in cellular component, which is currently the only accepted methodology to prevent transfusion-associated graft versus host disease (TA-GVHD). A range of irradiation dose levels between 15 Gy and 50 Gy is being used, but the majority of facilities are employing 15 Gy. It should, however, be recognized that the delivered dose in the instrument canister might differ from the actual dose absorbed by the blood bag. This study have evaluated the actual dose distribution under practical conditions where a container was loaded with blood products or water bags, or filled with distilled water. This approach provides data that the maximum attenuation occurred when the container was completely filled with a blood-compatible material. Thus, an error of approximately 20 percent should be considered in the dose measured in the in-air condition. A dose calibration in an in-air condition may lead to substantial underexposure of the blood products. A dose distribution study using adequately prearranged exposure period verified that the absorbed dose of 15 Gy was attained at any point in the container for both linear accelerator and gamma-irradiator. The maximal difference in the absorbed dose between measured points was 1.5- and 1.6-fold for linear accelerator and gamma-irradiator, respectively. In conclusion, using blood-compatible materials, a careful dose calibration study should be employed in which the absorbed dose of 15 Gy is obtained at the point where the lowest dose could be expected. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jeonghoon; Won, Eun-Ji; Lee, Bo-Young [Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Hwang, Un-Ki [Marine Ecological Risk Assessment Center, West Sea Fisheries Research Institute, National Fisheries Research and Development Institute, Incheon 400-420 (Korea, Republic of); Kim, Il-Chan; Yim, Joung Han [Division of Life Sciences, Korea Polar Research Institute, Incheon 406-840 (Korea, Republic of); Leung, Kenneth Mei Yee [School of Biological Sciences and the Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Road, Hong Kong (China); Lee, Yong Sung [Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@skku.edu [Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2014-07-01

    Highlights: • Mortality rate was significantly increased in response to gamma radiation. • A dose-dependent reduction in fecundity of ovigerous females. • Growth retardation, particularly at the nauplius stage. • Upon gamma radiation, T. japonicus showed an increased ROS levels. • Antioxidant genes and Hsps genes were upregulated at sublethal doses. - Abstract: Nuclear radioisotope accidents are potentially ecologically devastating due to their impact on marine organisms. To examine the effects of exposure of a marine organism to radioisotopes, we irradiated the intertidal copepod Tigriopus japonicus with several doses of gamma radiation and analyzed the effects on mortality, fecundity, and molting by assessing antioxidant enzyme activities and gene expression patterns. No mortality was observed at 96 h, even in response to exposure to a high dose (800 Gy) of radiation, but mortality rate was significantly increased 120 h (5 days) after exposure to 600 or 800 Gy gamma ray radiation. We observed a dose-dependent reduction in fecundity of ovigerous females; even the group irradiated with 50 Gy showed a significant reduction in fecundity, suggesting that gamma rays are likely to have a population level effect. In addition, we observed growth retardation, particularly at the nauplius stage, in individuals after gamma irradiation. In fact, nauplii irradiated with more than 200 Gy, though able to molt to copepodite stage 1, did not develop into adults. Upon gamma radiation, T. japonicus showed a dose-dependent increase in reactive oxygen species (ROS) levels, the activities of several antioxidant enzymes, and expression of double-stranded DNA break damage genes (e.g. DNA-PK, Ku70, Ku80). At a low level (sub-lethal dose) of gamma irradiation, we found dose-dependent upregulation of p53, implying cellular damage in T. japonicus in response to sub-lethal doses of gamma irradiation, suggesting that T. japonicus is not susceptible to sub-lethal doses of gamma

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    Highlights: • Mortality rate was significantly increased in response to gamma radiation. • A dose-dependent reduction in fecundity of ovigerous females. • Growth retardation, particularly at the nauplius stage. • Upon gamma radiation, T. japonicus showed an increased ROS levels. • Antioxidant genes and Hsps genes were upregulated at sublethal doses. - Abstract: Nuclear radioisotope accidents are potentially ecologically devastating due to their impact on marine organisms. To examine the effects of exposure of a marine organism to radioisotopes, we irradiated the intertidal copepod Tigriopus japonicus with several doses of gamma radiation and analyzed the effects on mortality, fecundity, and molting by assessing antioxidant enzyme activities and gene expression patterns. No mortality was observed at 96 h, even in response to exposure to a high dose (800 Gy) of radiation, but mortality rate was significantly increased 120 h (5 days) after exposure to 600 or 800 Gy gamma ray radiation. We observed a dose-dependent reduction in fecundity of ovigerous females; even the group irradiated with 50 Gy showed a significant reduction in fecundity, suggesting that gamma rays are likely to have a population level effect. In addition, we observed growth retardation, particularly at the nauplius stage, in individuals after gamma irradiation. In fact, nauplii irradiated with more than 200 Gy, though able to molt to copepodite stage 1, did not develop into adults. Upon gamma radiation, T. japonicus showed a dose-dependent increase in reactive oxygen species (ROS) levels, the activities of several antioxidant enzymes, and expression of double-stranded DNA break damage genes (e.g. DNA-PK, Ku70, Ku80). At a low level (sub-lethal dose) of gamma irradiation, we found dose-dependent upregulation of p53, implying cellular damage in T. japonicus in response to sub-lethal doses of gamma irradiation, suggesting that T. japonicus is not susceptible to sub-lethal doses of gamma

  14. Influence of genic status in relation to gamma ray and EMS induced pollen sterility in chillies (Capsicum Annum L.)

    International Nuclear Information System (INIS)

    Asha, M.S.; Nayar, N.K.

    1986-01-01

    Fifteen genotypes of the same species tested to study the effect of gamma rays and ethylmethane sulphonate showed wide variability in their effect. Pollen sterility increased with increase in dose. Gamma rays induced a higher per cent sterility compared to EMS. Genic status influenced variation was noted in the effect of mutagens in inducing pollen sterility. 7 refs. (author)

  15. Comparison of the effect of plasma treatment and gamma ray irradiation on PS-Cu nanocomposite films surface

    Science.gov (United States)

    Farag, O. F.

    2018-06-01

    Polystyrene-copper (PS-Cu) nanocomposite films were treated with DC N2 plasma and gamma rays irradiations. The plasma treatment of PS-Cu film surface was carried out at different treatment times, gas pressure 0.4 Torr and the applied power 3.5 W. On the other hand, the treatment with gamma rays irradiation were carried out at irradiation doses 10, 30 and 50 kGy. The induced changes in surface properties of PS-Cu films were investigated with UV-viss spectroscopy, scanning electron microscopy (SEM) and FTIR spectroscopy techniques. In addition, the wettability property, surface free energy, spreading coefficient and surface roughness of the treated samples were studied by measuring the contact angle. The UV-viss spectroscopy analysis revealed that the optical band gap decreases with increasing the treatment time and the irradiation dose for plasma and gamma treatments, respectively. SEM observations showed that the particle size of copper particles was increased with increasing the treatment time and the irradiation dose, but gamma treatment changes the copper particles size from nano scale to micro scale. The contact angle measurements showing that the wettability property, surface free energy, spreading coefficient and surface roughness of the treated PS-Cu samples were increased remarkably with increasing the treatment time and the irradiation dose for plasma and gamma treatments, respectively. The contact angle, surface free energy, spreading coefficient and surface roughness of the treated PS-Cu samples are more influenced by plasma treatment than gamma treatment.

  16. Gamma ray bursts observed with WATCH‐EURECA

    DEFF Research Database (Denmark)

    Brandt, Søren; Lund, Niels; Castro-Tirado, A. J.

    1994-01-01

    The WATCH wide field x‐ray monitor has the capability of independently locating bright Gamma Ray Bursts to 1° accuracy. We report the preliminary positions of 12 Gamma Ray Bursts observed with the WATCH monitor flown on the ES spacecraft EURECA during its 11 month mission. Also the recurrence...

  17. Evaluation of gamma dose effect on PIN photodiode using analytical model

    Science.gov (United States)

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

    2018-03-01

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

  18. Technology Needs for Gamma Ray Astronomy

    Science.gov (United States)

    Gehrels, Neil

    2011-01-01

    Gamma ray astronomy is currently in an exciting period of multiple missions and a wealth of data. Results from INTEGRAL, Fermi, AGILE, Suzaku and Swift are making large contributions to our knowledge of high energy processes in the universe. The advances are due to new detector and imaging technologies. The steps to date have been from scintillators to solid state detectors for sensors and from light buckets to coded aperture masks and pair telescopes for imagers. A key direction for the future is toward focusing telescopes pushing into the hard X-ray regime and Compton telescopes and pair telescopes with fine spatial resolution for medium and high energy gamma rays. These technologies will provide finer imaging of gamma-ray sources. Importantly, they will also enable large steps forward in sensitivity by reducing background.

  19. A study of gamma-ray bursts and a new detector for gamma-ray astronomy

    International Nuclear Information System (INIS)

    Carter, J.N.

    1979-09-01

    Three gamma-ray experiments flown on balloons between August 1975 and August 1976 are described in detail. The successful Transatlantic balloon flight enabled a rate of 3 bursts year -1 with energies > 7 x 10 -7 ergs cm -2 to be established. This result is discussed in the light of other work. The choice of γ-ray detector for optimum sensitivity is presented. In addition various techniques for determining the arrival direction of gamma-ray bursts are compared. A new balloon borne γ-ray burst telescope is proposed. The design, testing and results of the beam calibration of a new drift chamber detector system for high energy (> 50 MeV) γ-rays are presented. A projected angular resolution of 0.8 0 was obtained at 300 MeV. Techniques for the measurement of γ-ray energies are discussed in relation to this instrument. Finally the use of drift chambers in an integrated free flying satellite is illustrated, and the expected performance is presented. (author)

  20. Effect of low dose gamma-radiation upon Newcastle disease virus antibody level in chicken

    International Nuclear Information System (INIS)

    Vilic, M.; Gottstein, Z.; Ciglar Grozdanic, I.; Matanovic, K.; Miljanic, S.; Mazija, H.; Kraljevic, P.

    2009-01-01

    The specific antibody response against Newcastle disease virus in the blood serum of chickens hatched from eggs exposed to low dose gamma-radiation was studied. Materials and methods: Two groups of eggs of commercial meat chicken lines were irradiated with the dose of 0.30 Gy 60 Co gamma-rays before incubation and on the 19 th day of incubation, respectively. The same number of eggs unexposed to gamma-radiation served as controls. After hatching the group of chicken hatched from eggs irradiated on the 19 th day of incubation was not vaccinated while the group of chicken hatched from eggs irradiated before incubation was vaccinated on the 14 day. Specific serum anti-Newcastle disease virus antibodies were quantified by the hemagglutination inhibition assay with 4 HA units of Newcastle disease virus La Sota strain. Result: Specific antibody titres against Newcastle disease virus in the blood serum of chickens hatched from eggs irradiated before incubation and vaccinated on the 14 th day significantly increased on the 28 th day. Specific antibody titre against Newcastle disease virus in the blood serum of chickens hatched from eggs irradiated on the 19 th day of incubation and non-vaccinated was significantly higher on the 1 st and 14 th day. Conclusion: Acute irradiation of heavy breeding chicken eggs with the dose of 0.30 Gy 60 Co gamma-rays before incubation and on the 19 th day of incubation could have a stimulative effect on humoral immunity in chickens.

  1. Design and development of a PMOSFET gamma ray dosimeter

    International Nuclear Information System (INIS)

    Khanna, V.K.; Kumar, A.; Gupta, R.P.; Pandya, A.; Roy, Rajesh

    2005-01-01

    A P-channel MOSFET chip has been designed for detection of gamma radiations. The chip consists of three MOSFETs of different geometrical parameters for achieving sensitivity to low and high dose ranges. One of the MOSFET structures has a closed geometry to reduce the leakage current. The developed dosimeter being a MOSFET, its IC (Integrated Circuit)-compatibility helps in easy interfacing with readout circuitry. The dosimeter fabrication process is based on metal-gate MOSFET technology with thick gate oxide to increase the effective number of electron-hole pairs generated by the gamma rays impinging on the device. The process for the chip realization has been designed and simulated to achieve the required impurity diffusion profile. The chip has been fabricated using the above process and electrically characterized. The device has been exposed to gamma ray source and its characteristics measured. The change in threshold voltage of the MOSFET after exposure has been used to calculate the sensitivity of the device. The developed dosimeter has potential applications in personnel dosimetry and cancer treatment. This paper describes the basic detection mechanism of the MOSFET, the design approach, and fabrication process of the MOSFET dosimeter. (author)

  2. UNVEILING THE NATURE OF THE UNIDENTIFIED GAMMA-RAY SOURCES. III. GAMMA-RAY BLAZAR-LIKE COUNTERPARTS AT LOW RADIO FREQUENCIES

    Energy Technology Data Exchange (ETDEWEB)

    Massaro, F.; Funk, S. [SLAC National Laboratory and Kavli Institute for Particle Astrophysics and Cosmology, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); D' Abrusco, R.; Paggi, A. [Harvard-Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Giroletti, M. [INAF Istituto di Radioastronomia, via Gobetti 101, I-40129 Bologna (Italy); Masetti, N. [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna, via Gobetti 101, I-40129 Bologna (Italy); Tosti, G. [Dipartimento di Fisica, Universita degli Studi di Perugia, I-06123 Perugia (Italy); Nori, M. [Department of Physics and Astronomy, University of Bologna, viale Berti Pichat 6/2, I-40127 Bologna (Italy)

    2013-07-01

    About one-third of the {gamma}-ray sources listed in the second Fermi Large Area Telescope catalog (2FGL) have no firmly established counterpart at lower energies and so are classified as unidentified gamma-ray sources (UGSs). Here, we propose a new approach to find candidate counterparts for the UGSs based on the 325 MHz radio survey performed with the Westerbork Synthesis Radio Telescope in the northern hemisphere. First, we investigate the low-frequency radio properties of blazars, the largest known population of {gamma}-ray sources; then we search for sources with similar radio properties combining the information derived from the Westerbork Northern Sky Survey (WENSS) with those of the NRAO Very Large Array Sky Survey. We present a list of candidate counterparts for 32 UGSs with at least one counterpart in the WENSS. We also performed an extensive research in the literature to look for infrared and optical counterparts of the {gamma}-ray blazar candidates selected using the low-frequency radio observations to confirm their nature. On the basis of our multifrequency research, we identify 23 new {gamma}-ray blazar candidates out of the 32 UGSs investigated. Comparison with previous results on the UGSs is also presented. Finally, we speculate on the advantages of using low-frequency radio observations to associate UGSs and to search for {gamma}-ray pulsar candidates.

  3. Contribution to gamma ray transport calculation in heterogeneous media

    International Nuclear Information System (INIS)

    Bourdet, L.

    1985-04-01

    This thesis presents the development of gamma transport calculation codes in three dimension heterogeneous geometries. These codes allow us to define the protection against gamma-rays or verify their efficiency. The laws that govern the interactions of gamma-rays with matters are briefly revised. A library with the all necessary constants for these codes is created. TRIPOLI-2, a code that treats in exact way the neutron transport in matters using Monte-Carlo method, has been adapted to deal with the transport of gamma-rays in matters as well. TRINISHI, a code which considers only one collision, has been realized to treat heterogeneous geometries containing voids. Elaborating a formula that calculates the albedo for gamma-ray reflection (the code ALBANE) allows us to solve the problem of gamma-ray reflection on plane surfaces. NARCISSE-2 deals with gamma-rays that suffer only one reflection on the inner walls of any closed volume (rooms, halls...) [fr

  4. Pulser injection with subsequent removal for gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Hartwell, J.K.; Goodwin, S.G.; Johnson, L.O.; Killian, E.W.

    1990-01-01

    This patent describes a module for use with a gamma-ray spectroscopy system. The system includes a gamma-ray detector for detecting gamma-ray events and producing a signal representing the gamma-ray events, a converter responsive to the detector and capable of converting the signal to a spectrum, a storage memory responsive to the converter and capable of storing the spectrum at address locations in memory, and a pulser capable of injecting pulses into the signal produced by the detector. The module comprises: means for generating a logic pulse for controlling the pulser, the controlling means adapted for coupling to the pulser; means for generating separation of events logic to isolate the components of a combined gamma-ray---pulse spectrum, the separation of events logic means adapted for coupling to the converter and the storage memory with the capability of storing pulses at address locations in the storage memory separate from the gamma-ray events; means for receiving an imitating signal from the converter to generate a plurality of operations by the module; means for tracking variations in a gamma-ray---pulse spectrum brought on by external parameter changes; and means for interfacing with commercially developed gamma-ray spectrometry equipment

  5. Gamma-ray astronomy and cosmic-ray origin theory

    International Nuclear Information System (INIS)

    Ginzburg, V.L.

    1973-01-01

    A theory of the origin of cosmic radiation is discussed in light of the advances made in gamma-ray astronomy. Arguments against metagalactic models for the origin of cosmic rays are emphasized. (U.S.)

  6. Prompt gamma-ray analysis of steel slag in concrete

    International Nuclear Information System (INIS)

    Naqvi, Akhtar Abbas; Garwan, Muhammad Ahmad; Nagadi, Mahmoud Mohammad; Rehman, Khateeb-ur; Raashid, Mohammad; Masalehuddin Mohiuddin, Mohammad; Al-Amoudi, Omar Saeed Baghabra

    2009-01-01

    Blast furnace slag (BFS) is added to Portland cement concrete to increase its durability, particularly its corrosion resistance. Monitoring the concentration of BFS in concrete for quality control purposes is desired. In this study, the concentration of BFS in concrete was measured by utilizing an accelerator-based prompt gamma-ray neutron activation analysis (PGNAA) setup. The optimum size of the BFS cement concrete specimen that produces the maximum intensity of gamma rays at the detector location was calculated through Monte Carlo simulations. The simulation results were experimentally validated through the gamma-ray yield measurement from BFS cement concrete specimens having different radii. The concentration of BFS in the cement concrete specimens was assessed through calcium and silicon gamma-ray yield measurement from cement concrete specimens containing 5 to 80 wt% BFS. The yield of calcium gamma rays decreases with increasing BFS concentration in concrete while the yield of silicon gamma rays increases with increasing BFS concentration in concrete. The calcium-to-silicon gamma-ray yield ratio has an inverse relation with BFS concentration in concrete. (author)

  7. High dose effect of gamma and neutrons on the N-JFET electronic components

    International Nuclear Information System (INIS)

    Assaf, Jamal-Eddin

    2006-11-01

    Two types of N-JFET components have been irradiated by high doses of thermal neutrons and gamma rays up to 2000x10 12 n/cm 2 and 1000 kGy, respectively. The static tests show a decrease of the g m and I d s parameters. The behaviour of electronic noise on the output was the principal dynamic test after irradiation. The result of this test gives an increase of the noise with radiation dose increasing. The noise was described as the Equivalent Noise of Charge (ENC) at the output of the measurements set-up. The quantities and the qualities of the noise depend on the N-JEET type and the type of radiation (neutrons or gamma). Other tests were carried out like the relaxation or recovery phenomena after radiation, and the superposed effects of gamma and neutrons.(author)

  8. Use of gamma-rays sensitivity for discrimination of upland cultivars of groups Indican and Japonica

    International Nuclear Information System (INIS)

    Rodrigues, Luis Roberto Franco

    2003-01-01

    Sixty-five upland rice cultivars (Oryza sativa L.) were evaluated in relation to gamma-ray sensitivity. Seeds were subjected to seven doses of gamma-radiation and sown in wooden boxes in randomised complete block design with three replications. The experiment was conducted in greenhouse during the year of 1992. Physiological effects caused by radiation in the M 1 generation, were evaluated. The results showed that the sensitivity to the radiation at doses 300 and 360 Gy was useful for distinguishing Indican and Japonica groups. (author)

  9. Gamma Radiation Doses In Sweden

    International Nuclear Information System (INIS)

    Almgren, Sara; Isaksson, Mats; Barregaard, Lars

    2008-01-01

    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)μSv/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)μSv/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, 222 Rn measurements were performed in each dwelling, which showed no correlation with the gamma dose rates in the dwellings

  10. Interstellar medium structure and content and gamma ray astronomy

    International Nuclear Information System (INIS)

    Lebrun, F.

    1982-05-01

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

  11. Gamma Ray Tomographic Scan Method for Large Scale Industrial Plants

    International Nuclear Information System (INIS)

    Moon, Jin Ho; Jung, Sung Hee; Kim, Jong Bum; Park, Jang Geun

    2011-01-01

    The gamma ray tomography systems have been used to investigate a chemical process for last decade. There have been many cases of gamma ray tomography for laboratory scale work but not many cases for industrial scale work. Non-tomographic equipment with gamma-ray sources is often used in process diagnosis. Gamma radiography, gamma column scanning and the radioisotope tracer technique are examples of gamma ray application in industries. In spite of many outdoor non-gamma ray tomographic equipment, the most of gamma ray tomographic systems still remained as indoor equipment. But, as the gamma tomography has developed, the demand on gamma tomography for real scale plants also increased. To develop the industrial scale system, we introduced the gamma-ray tomographic system with fixed detectors and rotating source. The general system configuration is similar to 4 th generation geometry. But the main effort has been made to actualize the instant installation of the system for real scale industrial plant. This work would be a first attempt to apply the 4th generation industrial gamma tomographic scanning by experimental method. The individual 0.5-inch NaI detector was used for gamma ray detection by configuring circular shape around industrial plant. This tomographic scan method can reduce mechanical complexity and require a much smaller space than a conventional CT. Those properties make it easy to get measurement data for a real scale plant

  12. Measurement and calculation of characteristic prompt gamma ray spectra emitted during proton irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Polf, J C; Peterson, S; Beddar, S [M D Anderson Cancer Center, Univeristy of Texas, Houston, TX 77030 (United States); McCleskey, M; Roeder, B T; Spiridon, A; Trache, L [Cyclotron Institute, Texas A and M University, College Station, TX 77843 (United States)], E-mail: jcpolf@mdanderson.org

    2009-11-21

    In this paper, we present results of initial measurements and calculations of prompt gamma ray spectra (produced by proton-nucleus interactions) emitted from tissue equivalent phantoms during irradiations with proton beams. Measurements of prompt gamma ray spectra were made using a high-purity germanium detector shielded either with lead (passive shielding), or a Compton suppression system (active shielding). Calculations of the spectra were performed using a model of both the passive and active shielding experimental setups developed using the Geant4 Monte Carlo toolkit. From the measured spectra it was shown that it is possible to distinguish the characteristic emission lines from the major elemental constituent atoms (C, O, Ca) in the irradiated phantoms during delivery of proton doses similar to those delivered during patient treatment. Also, the Monte Carlo spectra were found to be in very good agreement with the measured spectra providing an initial validation of our model for use in further studies of prompt gamma ray emission during proton therapy. (note)

  13. Delayed radiation injury of gut-exposed and gut-shielded mice. I. The decrement in resistance to continuous gamma-ray stress

    International Nuclear Information System (INIS)

    Spalding, J.F.; Archuleta, R.F.; London, J.E.; Prine, J.R.

    1977-02-01

    Two mouse strains (RF/J and C57B1/6J) were exposed to x-ray doses totaling 400, 800, or 1200 rad. Total doses were given in 200-rad fractions at 7-day intervals to the whole body, gut only, or gut shielded. Animals treated as above (conditioned) were divided into 2 groups to form a two-part investigation. X-ray-conditioned and control mice were subjected to a continuous gamma-ray stress (challenge exposure) 28 days after the last x-ray dose. Delayed injury was measured as a reduction in mean after-survival (MAS) time and was observed in whole-body, gut-conditioned, and gut-shielded groups. The cause of death was attributed to hemopoietic hypoplasia in all groups. MAS reduction in all conditioned groups in both strains was linear with dose within the dose range used. Delayed injury per volume dose (measured as a reduction in MAS) was independent of the tissue initially conditioned with an acute dose of x rays. Thus, delayed injury per unit weight of gut tissue exposed was equal to that of either whole-body or gut-shielded radiation injury. Comparative weight loss observations during the continuous gamma-ray challenge exposure revealed a decrement in metabolic processes associated with body weight maintenance. This decrement was seen in all x-ray-conditioned groups

  14. Morphological mutations induced by gamma rays, ethylene imine and N-nitroso-N-ethyl urea in lentil (Lens culinaris medik.)

    International Nuclear Information System (INIS)

    Solanki, I.S.; Sharma, B.

    2003-01-01

    Dry and healthy seeds of a large seeded lentil cv, 'Precoz Selection', were treated with three doses each of gamma rays, ethylene imine (EI) and N-nitroso-N-ethyl urea (NEU). Based on the frequency of morphological mutations, the mutagens were arranged in the order: NEU > EI >. Gamma rays and dose-dependent relationship was observed in the case of gamma rays (5 kR 1 damage groups induced morphological mutations in the order: HH > HL > LH > LL. The morphological mutations included changes for growth habit, foliage, plant height and maturity and flowering behaviour. A mild relative mutagenic specificity and differences in mutability of genes for different traits were observed, In general the spectrum of morphological mutations was not influenced by the groups of M 1 damage, except that some mutation types occurred more frequently, than others in certain groups. (author)

  15. Annual increments, specific gravity and energy of Eucalyptus grandis by gamma-ray attenuation technique

    International Nuclear Information System (INIS)

    Rezende, M.A.; Guerrini, I.A.; Ferraz, E.S.B.

    1990-01-01

    Specific gravity annual increments in volume, mass and energy of Eucalyptus grandis at thirteen years of age were made taking into account measurements of the calorific value for wood. It was observed that the calorific value for wood decrease slightly, while the specific gravity increase significantly with age. The so-called culmination age for the Annual Volume Increment was determined to be around fourth year of growth while for the Annual Mass and Energy Increment was around the eighty year. These results show that a tree in a particular age may not have a significant growth in volume, yet one is mass and energy. (author)

  16. The Effect of Material Homogenization in Calculating the Gamma-Ray dose from Spent PWR Fuel Pins in an Air Medium

    International Nuclear Information System (INIS)

    TH Trumbull

    2005-01-01

    The effect of material homogenization on the calculated dose rate was studied for several arrangements of typical PWR spent fuel pins in an air medium using the Monte Carlo code, MCNP. The models analyzed increased in geometric complexity, beginning with a single fuel pin, progressing to ''small'' lattices, i.e., 3x3, 5x5, 7x7 fuel pins, and culminating with a full 17x17 pin PWR bundle analysis. The fuel pin dimensions and compositions were taken directly from a previous study and efforts were made to parallel this study by specifying identical flux-to-dose functions and gamma-ray source spectra. The analysis shows two competing components to the overall effect of material homogenization on calculated dose rate. Homogenization of pin lattices tends to lower the effect of radiation ''channeling'' but increase the effect of ''source redistribution.'' Depending on the size of the lattice and location of the detectors, the net effect of material homogenization on dose rate can be insignificant or range from a 6% decrease to a 35% increase relative to the detailed geometry model

  17. Dose and dose rate effects of whole-body gamma-irradiation: I. Lymphocytes and lymphoid organs

    Science.gov (United States)

    Pecaut, M. J.; Nelson, G. A.; Gridley, D. S.

    2001-01-01

    The major goal of part I of this study was to compare varying doses and dose rates of whole-body gamma-radiation on lymphoid cells and organs. C57BL/6 mice (n = 75) were exposed to 0, 0.5, 1.5, and 3.0 Gy gamma-rays (60Co) at 1 cGy/min (low-dose rate, LDR) and 80 cGy/min (high-dose rate, HDR) and euthanized 4 days later. A significant dose-dependent loss of spleen mass was observed with both LDR and HDR irradiation; for the thymus this was true only with HDR. Decreasing leukocyte and lymphocyte numbers occurred with increasing dose in blood and spleen at both dose rates. The numbers (not percentages) of CD3+ T lymphocytes decreased in the blood in a dose-dependent manner at both HDR and LDR. Splenic T cell counts decreased with dose only in HDR groups; percentages increased with dose at both dose rates. Dose-dependent decreases occurred in CD4+ T helper and CD8+ T cytotoxic cell counts at HDR and LDR. In the blood the percentages of CD4+ cells increased with increasing dose at both dose rates, whereas in the spleen the counts decreased only in the HDR groups. The percentages of the CD8+ population remained stable in both blood and spleen. CD19+ B cell counts and percentages in both compartments declined markedly with increasing HDR and LDR radiation. NK1.1+ natural killer cell numbers and proportions remained relatively stable. Overall, these data indicate that the observed changes were highly dependent on the dose, but not dose rate, and that cells in the spleen are more affected by dose rate than those in blood. The results also suggest that the response of lymphocytes in different body compartments may be variable.

  18. Electrical resistance behavior with gamma radiation dose in bulk carbon nanostrutured samples

    International Nuclear Information System (INIS)

    Lage, J.; Leyva, A.; Pinnera, I.; Desdin, L. F.; Abreu, Y.; Cruz, C. M.; Leyva, D.; Toledo, C.

    2013-01-01

    The aim of this paper is to study the effects of 60 Co gamma radiation on the electrical resistance and V-I characteristic of bulk carbon nano structured samples obtained by electric arc discharge in water method. Images of pristine samples obtained with scanning electron, and the results in graphical form of the electrical characterization of irradiated samples are presented in the text. It was observed that the electrical resistance vs. dose behavior shows an initial increment reaching the maximum at approximately 135 kGy, followed by a drop of the resistance values. These behaviors are associated with the progressive generation of radiation induced defects in the sample, whose number increases to reach saturation at 135 kGy. From this dose, defects could lead to cross-links between different nano structures present in the sample conducting to a gradually drop in electrical resistance. The measured V-I curves show that, increasing exposure to the 60 Co gamma radiation, the electrical properties of the studied samples transit from a semiconductor towards a predominantly metallic behavior. These results were compared with those obtained for a sample of graphite powder irradiated under the same conditions. (Author)

  19. The use of gamma ray data to define the natural radiation environment

    International Nuclear Information System (INIS)

    1990-09-01

    The natural radiation environment is the major source of radiation exposure to man and consists of both internal and external sources. The most significant internal sources are the radioactive elements 40 K and 222 Rn which are taken into the body. The external sources are cosmic rays and naturally occurring radioactive isotopes of the 40 K, 238 U, and 232 Th decay series, some or all of which can be found in the ground, in construction materials, and in the air. This report has been prepared to provide a guide for the use of existing gamma ray survey data to define the natural radiation environment, but will only be concerned with the gamma ray exposure resulting from radiation originating in geological materials. The type of data needed to produce maps are available as a result of airborne, carborne, and ground gamma ray surveys in many parts of the world. Although most of these data were acquired for uranium and other mineral exploration and geological mapping purposes, they can be used to provide background radioactivity information. Standardized survey data can be compiled to produce regional maps of gamma ray air dose rates as well as single radioelement maps. Compilation procedures may use either manual or computer techniques. Although this work will primarily be done as national compilations, it will open the possibility of the compilation of radioelement geochemical maps on a regional and global scale. 48 refs, figs and tabs

  20. Autoradiographic study of gamma-ray induced unscheduled DNA synthesis in bean root meristem cells

    International Nuclear Information System (INIS)

    Liu Zhenshen; Qiu Quanfa; Chen Dongli

    1989-01-01

    The gamma-ray induced unscheduled DNA synthesis in root meristem cells of Vica faba was studied autoradiographically by calculating the number of cells with different 3H-thymidine labelling degree. It was found that the level of unscheduled synthesis in cells with intermediate dose (500 R) irradiation was higher than that in cells with lower dose (250 R) irradiation; however, higher dose (1000 R) irradiation would inhibit the reparative replication

  1. Effects of gamma-ray irradiation on cellulase secretion of Trichoderma reesei

    International Nuclear Information System (INIS)

    Tamada, M.; Kasai, N.; Kaetsu, I.

    1987-01-01

    Trichoderma reesei was irradiated with gamma rays to investigate the effects of different dosages on cellulase production. Doses above 0.7 kGy induced cell lysis. Cell growth began to be obstructed at 2.0 kGy. As a result, the cells irradiated at 2.0 kGy secreted 1.8 times as much cellulase as the untreated cells

  2. Induction of mutations by chemicals and gamma rays in mutants of yeast refractory to UV-mutagenesis

    International Nuclear Information System (INIS)

    Nasim, A.; Hannan, M.A.

    1977-01-01

    Radiation-sensitive mutants of Schizosaccharomyces pombe, known to be refractory to UV-mutagenesis, were tested for mutability caused by treatments with chemicals and gamma rays. One such mutant (rad3) was studied over a wide range of UV doses to compare the kinetics of its mutational response to that of the wild type. All such comparisons were carried out using a forward mutation system. Data show that, unlike UV, the chemical mutagens as well as gamma rays produced mutations (although at reduced frequency), in the strains of S. pombe tested, indicating the existence of an additional mechanism(s) for chemical and gamma ray induced mutations. These observations are discussed as these relate to the pathways for repair of mutational damage in yeast. (author)

  3. CENTRAL ENGINE MEMORY OF GAMMA-RAY BURSTS AND SOFT GAMMA-RAY REPEATERS

    International Nuclear Information System (INIS)

    Zhang, Bin-Bin; Castro-Tirado, Alberto J.; Zhang, Bing

    2016-01-01

    Gamma-ray bursts (GRBs) are bursts of γ-rays generated from relativistic jets launched from catastrophic events such as massive star core collapse or binary compact star coalescence. Previous studies suggested that GRB emission is erratic, with no noticeable memory in the central engine. Here we report a discovery that similar light curve patterns exist within individual bursts for at least some GRBs. Applying the Dynamic Time Warping method, we show that similarity of light curve patterns between pulses of a single burst or between the light curves of a GRB and its X-ray flare can be identified. This suggests that the central engine of at least some GRBs carries “memory” of its activities. We also show that the same technique can identify memory-like emission episodes in the flaring emission in soft gamma-ray repeaters (SGRs), which are believed to be Galactic, highly magnetized neutron stars named magnetars. Such a phenomenon challenges the standard black hole central engine models for GRBs, and suggest a common physical mechanism behind GRBs and SGRs, which points toward a magnetar central engine of GRBs

  4. Applications of Monte Carlo simulations of gamma-ray spectra

    International Nuclear Information System (INIS)

    Clark, D.D.

    1995-01-01

    A short, convenient computer program based on the Monte Carlo method that was developed to generate simulated gamma-ray spectra has been found to have useful applications in research and teaching. In research, we use it to predict spectra in neutron activation analysis (NAA), particularly in prompt gamma-ray NAA (PGNAA). In teaching, it is used to illustrate the dependence of detector response functions on the nature of gamma-ray interactions, the incident gamma-ray energy, and detector geometry

  5. Simulation study on the behavior of X-rays and gamma rays in an inhomogeneous medium using the Monte Carlo technique

    International Nuclear Information System (INIS)

    Murase, Kenya; Kataoka, Masaaki; Kawamura, Masashi; Tamada, Shuji; Hamamoto, Ken

    1989-01-01

    A computer program based on the Monte Carlo technique was developed for the analysis of the behavior of X-rays and gamma rays in an inhomogeneous medium. The statistical weight of a photon was introduced and the survival biasing method was used for reducing the statistical error. This computer program has the mass energy absorption and attenuation coefficients for 69 tissues and organs as a database file, and can be applied to various cases of inhomogeneity. The simulation and experimental results of the central axis percent-depth dose in an inhomogeneous phantom were in good agreement. This computer program will be useful for analysis on the behavior of X-rays and gamma rays in an inhomogeneous medium consisting of various tissues and organs, not only in radiotherapy treatment planning but also in diagnostic radiology and in the field treating radiation protection. (author)

  6. Fermi GBM Observations of Terrestrial Gamma-Ray Flashes

    Science.gov (United States)

    Wilson-Hodge, Colleen A.; Briggs, M. S.; Connaughton, V.; Fishman, G. J.; Bhat, P. N.; Paciesas, W. S.; Preece, R.; Kippen, R. M.; vonKienlin, A.; Dwyer, J. R.; hide

    2010-01-01

    This slide presentation explores the relationship between Terrestrial Gamma-Ray Flashes (TGF) and lightning. Using data from the World-Wide Lightning Location Network (WWLLN), and the gamma ray observations from Fermi's Gamma-ray Burst Monitor (GBM), the study reviews any causal relationship between TGFs and lightning. The conclusion of the study is that the TGF and lightning are simultaneous with out a causal relationship.

  7. Gamma-ray burst spectra

    International Nuclear Information System (INIS)

    Teegarden, B.J.

    1982-01-01

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

  8. Gamma-ray Imaging Methods

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-10-05

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

  9. Gamma-ray imaging spectrometer (GRIS): a new balloon-borne experiment for gamma-ray line astronomy

    International Nuclear Information System (INIS)

    Teegarden, B.J.; Cline, T.L.; Gehrels, N.; Porreca, G.; Tueller, J.; Leventhal, M.; Huters, A.F.; MacCallum, C.J.; Stang, P.D.

    1985-01-01

    High resolution gamma-ray spectroscopy is a relatively new field that holds great promise for further understanding of high energy astrophysical processes. Preliminary results such as the annihilation radiation from the galactic center, the 26 Al line from the galactic plane and cyclotron lines from neutron stars may well be just the initial discoveries of a rich and as yet undeveloped field. When the high resolution gamma-ray spectrometer (GRSE) was removed from the GRO payload NASA decided to initiate a balloon program to permit continued development and improvement of instrumentation in this field, as well as continued scientific observations. The Gamma-Ray Imaging Spectrometer (GRIS) is one of the experiments selected as part of this program. The instrument contains a number of new and innovative features that are expected to produce a significant improvement in source location accuracy and sensitivity over previous balloon and satellite experiments. 6 refs., 2 figs

  10. Effects of sublethal doses of gamma radiation on the developing rat brain

    International Nuclear Information System (INIS)

    Cerda, H.; Carlsson, J.; Larsson, B.; Saefwenberg, J.O.

    1975-01-01

    Newborn rats were irradiated with 60 Co gamma rays. Doses of 0, 80 or 160 rads were given to the whole body. The whole body and brain weights, DNA and RNA contents of the brain and 3 H-thymidine or 3 H-uridine incorporated by the brain were measured at 5, 10 or 15 days after birth. A dose of 160 rads produced clear alterations in the brain but no clear effects could be detected when 80 rads were given. (author)

  11. External dose rates from gamma rays and activity concentrations in foodstuffs and herbage in eastern Europe

    International Nuclear Information System (INIS)

    Wilkins, B.T.; Dodd, N.J.; Bradley, E.J.

    1986-01-01

    The initial scarcity of reliable information in eastern European countries, coupled with the proximity of the Chernobyl installation, resulted in understandable concern among British nationals living in these areas or visiting them on a short-term basis. Accordingly, arrangements were made by the Foreign and Commonwealth Office (FCO) for the appropriate Embassies to send samples of milk, drinking water, grass and available fruit and vegetables to the Board's laboratories at Chilton for analysis. In addition, simple monitoring equipment was supplied to the Embassies for measurements of external dose rates from gamma rays out of doors. The first set of samples was collected in Moscow on May 3rd 1986. Most consignments arrived at Chilton within 24 hours of collection. Speed was important, not only because of the need for information but because vegetation needed to be sufficiently fresh to permit meaningful measurement. By the end of June 1986, the results of systematic monitoring programmes in eastern Europe were being disseminated more freely, so that frequent sampling by the Embassies was no longer considered necessary. Since that time samples have been received only occasionally from those Embassies where concern still persists. This report summarises the results of measurements and samples taken by June 30th 1986. Data for γ-ray emitting radionuclides in foodstuffs were issued to the FCO in a series of Measurement Reports. Here they are presented together with data for actinide element concentrations in a limited number of samples. Measurements of outdoor external dose rates made by the Embassies are also included

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

    International Nuclear Information System (INIS)

    Kimura, Hiroshi

    1981-01-01

    This report intends to clarify the relationship between the total exposure dose and scratch resistance to the specimens SF, SH, MF and MH, giving coating treatments to P.M.M.A. (dental polymethylmethacrylate) and exposing to the irradiation of 60 Co gamma ray at each dose rate. And based on the results, it is intended to develop coated P.M.M.A. with excellent scratch resistance give by irradiation of radioactive ray. From this study, the following results have been obtained. Irradiation of 60 Co gamma ray would give the best results at the exposure at 1 x 10 6 R. The SF and SH specimens in wet condition exposed to 60 Co gamma ray irradiation at 1 x 10 6 R showed a quantity of abrasion of only 17% that of untreated P.M.M.A. and the barrel test revealed outstanding abrasion and scratch resistance. Abrasion and scratch resistance of coated specimens are better utilized in wet conditions performing three times better than those in dry conditions. (author)

  13. Gamma-ray pulsars: Emission zones and viewing geometries

    Science.gov (United States)

    Romani, Roger W.; Yadigaroglu, I.-A.

    1995-01-01

    There are now a half-dozen young pulsars detected in high-energy photons by the Compton Gamma-Ray Observatory (CGRO), showing a variety of emission efficiencies and pulse profiles. We present here a calculation of the pattern of high-energy emission on the sky in a model which posits gamma-ray production by charge-depleted gaps in the outer magnetosphere. This model accounts for the radio to gamma-ray pulse offsets of the known pulsars, as well as the shape of the high-energy pulse profiles. We also show that about one-third of emitting young radio pulsars will not be detected due to beaming effects, while approximately 2.5 times the number of radio-selected gamma-ray pulsars will be viewed only high energies. Finally we compute the polarization angle variation and find that the previously misunderstood optical polarization sweep of the Crab pulsar arises naturally in this picture. These results strongly support an outer magnetosphere location for the gamma-ray emission.

  14. CAMAC gamma ray scanning system

    International Nuclear Information System (INIS)

    Moss, C.E.; Pratt, J.C.; Shunk, E.R.

    1981-01-01

    A flexible gamma-ray scanning system, based on a LeCroy 3500 multichannel analyzer and CAMAC modules, is described. The system is designed for making simultaneous passive and active scans of objects of interest to nuclear safeguards. The scanner is a stepping-motor-driven carriage; the detectors, a bismuth-germanate scintillator and a high-purity germanium detector. A total of sixteen peaks in the two detector-produced spectra can be integrated simultaneously, and any scan can be viewed during data acquisition. For active scanning, the 2615-keV gamma-ray line from a 232 U source and the 4439-keV gamma-ray line from 9 Be(α,n) 12 C were selected. The system can be easily reconfigured to accommodate up to seven detectors because it is based on CAMAC modules and FORTRAN. The system is designed for field use and is easily transported. Examples of passive and active scans are presented

  15. Population Studies of Radio and Gamma-Ray Pulsars

    Science.gov (United States)

    Harding, Alice K; Gonthier, Peter; Coltisor, Stefan

    2004-01-01

    Rotation-powered pulsars are one of the most promising candidates for at least some of the 40-50 EGRET unidentified gamma-ray sources that lie near the Galactic plane. Since the end of the EGRO mission, the more sensitive Parkes Multibeam radio survey has detected mere than two dozen new radio pulsars in or near unidentified EGRET sources, many of which are young and energetic. These results raise an important question about the nature of radio quiescence in gamma-ray pulsars: is the non-detection of radio emission a matter of beaming or of sensitivity? The answer is very dependent on the geometry of the radio and gamma-ray beams. We present results of a population synthesis of pulsars in the Galaxy, including for the first time the full geometry of the radio and gamma-ray beams. We use a recent empirically derived model of the radio emission and luminosity, and a gamma-ray emission geometry and luminosity derived theoretically from pair