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Sample records for whole-body neutron gamma

  1. Application of Whole Body Counter to Neutron Dose Assessment in Criticality Accidents

    Energy Technology Data Exchange (ETDEWEB)

    Kurihara, O.; Tsujimura, N.; Takasaki, K.; Momose, T.; Maruo, Y. [Japan Nuclear Cycle Development Institute, Tokai (Japan)

    2001-09-15

    Neutron dose assessment in criticality accidents using Whole Body Counter (WBC) was proved to be an effective method as rapid neutron dose estimation at the JCO criticality accident in Tokai-mura. The 1.36MeV gamma-ray of {sup 24}Na in a body can be detected easily by a germanium detector. The Minimum Detectable Activity (MDA) of {sup 24}Na is approximately 50Bq for 10minute measurement by the germanium-type whole body counter at JNC Tokai Works. Neutron energy spectra at the typical shielding conditions in criticality accidents were calculated and the conversion factor, whole body activity-to-organ mass weighted neutron absorbed dose, corresponding to each condition were determined. The conversion factor for uncollied fission spectrum is 7.7 [(Bq{sup 24}Na/g{sup 23}Na)/mGy].

  2. Hematologic status of mice submitted to sublethal total body irradiation with mixed neutron-gamma radiation

    International Nuclear Information System (INIS)

    Herodin, F.; Court, L.

    1989-01-01

    The hematologic status of mice exposed to sublethal whole body irradiation with mixed neutron-gamma radiation (mainly neutrons) is studied. A slight decrease of the blood cell count is still observed below 1 Gy. The recovery of bone marrow granulocyte-macrophage progenitors seems to require more time than after pure gamma irradiation [fr

  3. Effect of liposome entrapped Cu/Zn bovine superoxide dismutase in rat after total body (neutron-gamma) irradiation

    International Nuclear Information System (INIS)

    Lamproglou, I.; Martin, S.; Lambert, F.; Fontanille, P.; Fessi, H.; Puisieux, F.; Colas-Linhart, N.; Bok, B.; Fatome, M.; Martin, C.

    1998-01-01

    Our purpose was, to study in rat the effects of (neutron-gamma) exposure and of LIPSOD treatment (liposomal Cu/Zn super-oxide dismutase) on cognitive functions. Our data demonstrate that whole-body irradiation induces in Sprague-Dawley rats some cognitive dysfunction. Treatment using LIPSOD corrects in a significantly way this trend. Moreover, in sham-irradiated rats, this treatment shows an inhibitory effect. (authors)

  4. 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.

  5. 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

  6. Measurement of whole body cellular and collagen nitrogen, potassium, and other elements by neutron activation and whole body counting

    International Nuclear Information System (INIS)

    James, H.M.; Fabricius, P.J.; Dykes, P.W.

    1987-01-01

    Whole body nitrogen can be measured by neutron activation analysis with an acceptable radiation dose; it is an index of body protein which, in normal subjects, is 65% cellular protein and 35% extracellular connective collagen. Whole body potassium can be measured by whole body counting without irradiating the subject; it is an index of body cell mass. We measured whole body nitrogen, potassium, extracellular water, intracellular water, and fat-folds. The differences between 37 malnourished patients and five normal subjects suggested that the patients had 9 kg less cell mass than normal, but no difference in extracellular mass. Measurements were made on eight patients before and after 14 days of total parenteral nutrition; balance of nitrogen intake and excretion also was measured. The changes were consistent with mean increases of 3 kg of cellular mass and 3 kg of fat with no change of extracellular mass. The accuracy and sensitivity of the whole body measurements need further confirmation for use in patients with changing body composition. Where tissue wasting is largely from the cellular compartment, potassium could be a more sensitive index of wasting than nitrogen. Multielement analysis of nitrogen, potassium, chlorine, and carbon will probably be valuable in elucidating body composition in malnutrition

  7. Measurement of total body chlorine by prompt gamma in vivo neutron activation analysis

    International Nuclear Information System (INIS)

    Beddoe, A.H.; Streat, S.J.; Hill, G.L.

    1987-01-01

    A method of measuring total body chlorine (TBCl) by prompt gamma in vivo neutron activation analysis is described depending on the same NaI(Tl) spectra used for determinations of total body nitrogen. Ratios of chlorine to hydrogen are derived and TBCl determined using a model of body composition depending on measured body weight, total body water (by tritium dilution) and protein (6.25 x nitrogen) as well as estimated body minerals and glycogen. The precision of the method based on scanning an anthropomorphic phantom is approximately 9% (SD), for a patient dose equivalent of less than 0.30 mSv. Spectra collected from 67 normal volunteers (32 male, 35 female) yielded mean values of TBCl of 72 +- 19 (SD) g in males and 53.6 +- 15 g in females, in broad agreement with values reported by workers using delayed gamma methods. Results are presented for two human cadavers analysed by neutron activation and conventional chemical analysis; the ratios of TBCl (neutron activation) to TBCl (chemical) were 0.980 +- 0.028 (SEM) and 0.91 +- 0.09. It is suggested that an improvement in precision will be achieved by increasing the scanning time (thereby increasing the radiation dose equivalent) and by adding two more detectors. (author)

  8. Chemical radioprotection to bone marrow stem cells after whole body gamma irradiation to mice

    Energy Technology Data Exchange (ETDEWEB)

    Dey, J.; Dey, T.B.; Ganguly, S.K.; Nagpal, K.K.; Ghose, A.

    1988-11-01

    Protection to mice bone marrow stem cells has been noted as early as two days after whole body gamma ray exposure by prior treatment with combination of hydroxytryptophan (HT) and one of the two thiol drugs viz., aminoethylisothiuronium bromide hydrobromide (AET) (20 mg/kg body weight) and B-mercaptopropionylglicine (MPG). The levels of protection to bone marrow stem cells thus obtained have been compared to that obtained by treating with the optimum radioprotecting dose of AET (200 mg/kg body weight). The study reports the bone marrow stem cells status after two days of 3 Gy, 5 Gy and 10 Gy whole body gamma irradiation in relation to the mentioned radioprotecting treatments as studied by spleen colony forming method.

  9. Monte Carlo simulated dose to the human body due to neutrons emitted in laser-fusion

    International Nuclear Information System (INIS)

    Gileadi, A.E.; Cohen, M.O.

    1977-01-01

    Considering a point neutron source located at a given distance from the human body, modeled by a 'standard reference man' phantom, neutron doses to the whole body, as well as to selected organs thereof, are determined, using the SAM-CE system, a Monte Carlo computer code, written in Fortran and designed to solve time, space and energy dependent neutron and gamma ray transport equations in complex three-dimensional geometrice. Collision density, energy deposition and dose are treated in the SAM-CE system as flux functionals. A special feature of SAM-CE is its use of the 'Combinatorial Geometry' technique which affords the user geometric capabilities exceeding those available with other commonly used geometric packages. All neutron and gamma ray cross section data, as well as gamma ray production data, are derived from the ENDF libraries. Both resolved and unresolved resonance parameters from ENDF neutron data files are treated automatically and extremely precise and detailed descriptions of cross section behavior is permitted. Such treatment avoids the ambiguities usually associated with multi-group codes, which use flux-averaged cross sections based on assumed flux distributions which may or may not be appropriate. The 'standard reference man', a heterogeneous phantom, uses simple geometric forms to approximate the shape and dimensions of the human body. Materials composition of each subregion representing a certain 'organ' is given. Typical values of neutron doses to the whole body and to selected 'organs' of interest are presented

  10. Body composition to climate change studies - the many facets of neutron induced prompt gamma-ray analysis

    International Nuclear Information System (INIS)

    Mitra, S.

    2008-01-01

    In-vivo body composition analysis of humans and animals and in-situ analysis of soil using fast neutron inelastic scattering and thermal neutron capture induced prompt-gamma rays have been described. By measuring carbon (C), nitrogen (N) and oxygen (O), protein, fat and water are determined. C determination in soil has become important for understanding below ground carbon sequestration process in the light of climate change studies. Various neutron sources ranging from radio isotopic to compact 14 MeV neutron generators employing the associated particle neutron time-of-flight technique or micro-second pulsing were implemented. Gamma spectroscopy using recently developed digital multi-channel analyzers has also been described

  11. Body composition to climate change studies - the many facets of neutron induced prompt gamma-ray analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mitra,S.

    2008-11-17

    In-vivo body composition analysis of humans and animals and in-situ analysis of soil using fast neutron inelastic scattering and thermal neutron capture induced prompt-gamma rays have been described. By measuring carbon (C), nitrogen (N) and oxygen (O), protein, fat and water are determined. C determination in soil has become important for understanding below ground carbon sequestration process in the light of climate change studies. Various neutron sources ranging from radio isotopic to compact 14 MeV neutron generators employing the associated particle neutron time-of-flight technique or micro-second pulsing were implemented. Gamma spectroscopy using recently developed digital multi-channel analyzers has also been described.

  12. Total body-calcium measurements: comparison of two delayed-gamma neutron activation facilities

    International Nuclear Information System (INIS)

    Ma, R.; Ellis, K.J.; Shypailo, R.J.; Pierson, R.N. Jr.

    1999-01-01

    This study compares two independently calibrated delayed-gamma neutron activation (DGNA) facilities, one at the Brookhaven National Laboratory (BNL), Upton, New York, and the other at the Children's Nutrition Research Center (CNRC), Houston, Texas that measure total body calcium (TBCa). A set of BNL phantoms was sent to CNRC for neutron activation analysis, and a set of CNRC phantoms was measured at BNL. Both facilities showed high precision (<2%), and the results were in good agreement, within 5%. (author)

  13. Influence of whole-body gamma irradiation upon arachidonic acid metabolism in rat platelets

    International Nuclear Information System (INIS)

    Lognonne, J.L.; Ducousso, R.; Rocquet, G.; Kergonou, J.F.

    1985-01-01

    The effects of whole-body gamma irradiation (8.4 Gy) were studied on arachidonic acid (AA) metabolism in rat's blood platelets, from day D + 1 to day D + 10 after irradiation. AA conversion into thromboxane B 2 (TxB 2 ) increased at D + 1 and then gradually decreased to very low values from D + 7 to D + 10. This decrease in the conversion of exogenous AA into TxB 2 was due to a lower AA incorporation into platelets and not to a decrease of cyclooxygenase and thromboxane-synthetase activities. AA incorporation into membrane phospholipids of blood platelets was much more decreased than AA incorporation into whole platelets; moreover, the lipid composition of the platelet membranes was markedly modified after irradiation, which must have resulted in structural and functional changes in these membranes; from these effects of whole-body gamma irradiation on platelets, the latter's membranes appeared as a major site of in vivo radiation damage in these cells

  14. Acid base balance in the rabbit following whole-body gamma irradiation

    International Nuclear Information System (INIS)

    Bassant, M.-H.; Touchard, Francoise; Court, Louis

    1981-01-01

    2 hrs. after whole-body gamma irradiation (doses of 1.5 and 4.5 Gy) a metabolic acidosis developed in curarised Rabbits placed under artificial respiration in order to eliminate radiation-induced respiratory effect. The metabolic acidosis was evaluated by measurement of the negative base excess. The results were compared to others obtained under different experimental procedures [fr

  15. Acid base balance in the rabbit following whole-body gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Bassant, M.H.; Touchard, F.; Court, L. (CEA Centre d' Etudes Nucleaires de Fontenay-aux-Roses, 92 (France). Dept. de Recherches sur la Fusion Controlee)

    1981-07-06

    2 hrs. after whole-body gamma irradiation (doses of 1.5 and 4.5 Gy) a metabolic acidosis developed in curarised rabbits placed under artificial respiration in order to eliminate radiation-induced respiratory effect. The metabolic acidosis was evaluated by measurement of the negative base excess. The results were compared to others obtained under different experimental procedures.

  16. In vivo measurement of total body carbon using 238Pu/Be neutron sources

    International Nuclear Information System (INIS)

    Sutcliffe, J.F.; Mitra, S.; Hill, G.L.

    1990-01-01

    Total body carbon has been measured by in vivo neutron activation analysis (IVNAA) in 278 surgical gastroenterological patients and 29 normal volunteers. This is based on the inelastic scattering reaction { 12 C(n,n') 12 C*} for neutrons with energy above 4.8MeV, producing 4.43 MeV gamma rays. Since only part of the body is scanned, total body carbon is estimated as the ratio of the gamma ray emission from carbon to the emission from hydrogen, using hydrogen as the internal standard. The precision of the estimate is ±1.6kg for a whole body dose of 0.3mSv. There is a significant difference between the estimates of total body water from IVNAA measurements of carbon and nitrogen and measurements of body water in these subjects by tritium dilution (t=3.1, p < 0.005). (author)

  17. High-resolution gamma spectroscopy with whole-body and partial-body counters. Experience, recommendations. Report

    International Nuclear Information System (INIS)

    Sahre, P.

    1997-12-01

    The application of high-resolution gamma spectroscopy with whole-body and partial-body counters shows a steadily rising upward trend over the last few years. This induced the ''Arbeitskreis Inkorporationsueberwachung'' of the association ''Fachverband fuer Strahlenschutz e.V.'' to organise a meeting for joint elaboration of a guide on recommended applications of this measuring technique, based on a review of existing experience and results. A key item on the agenda of the meeting was the comparative evaluation of the Ge semiconductor detector and the NaI solid scintillation detector. (orig./CB) [de

  18. Computer generated multi-color graphics in whole body gamma spectral analysis

    International Nuclear Information System (INIS)

    Phillips, W.G.; Curtis, S.P.; Environmental Protection Agency, Las Vegas, NV)

    1984-01-01

    A medium resolution color graphics terminal (512 x 512 pixels) was appended to a computerized gamma spectrometer for the display of whole body counting data. The color display enhances the ability of a spectroscopist to identify at a glance multicolored spectral regions of interest immediate qualitative interpretation. Spectral data from subjects containing low concentrations of gamma emitters obtained by both NaI(T1) and phoswich detectors are viewed by the method. In addition, software generates a multispectral display by which the gross, background, and net spectra are displayed in color simultaneously on a single screen

  19. Whole body analysis of the knockout gene mouse model for cystic fibrosis using thermal and fast neutron activation analysis

    International Nuclear Information System (INIS)

    Mason, M.M.; Morris, J.S.; Derenzy, B.A.; Spate, V.L.; Horsman, T.L.; Baskett, C.K.; Nichols, T.A.; Colbert, J.W.; Clarke, L.L.; Gawenis, L.R.; Hillman, L.S.

    1998-01-01

    A genetically engineered 'knockout gene' mouse model for human cystic fibrosis (CF) has been utilized to study bone mineralization. In CF, the so-called cystic fibrosis transmembrane conductance regulator (CFTR) protein, a chloride ion channel, is either absent or defective. To produce the animal model the murine CFTR gene has been inactivated producing CF symptoms in the homozygotic progeny. CF results in abnormal intestinal absorption of minerals and nutrients which presumably results in substandard bone mineralization. The objective of this study was to determine the feasibility of using whole-body thermal and fast neutron activation analysis to determine mineral and trace-element differences between homozygote controls (+/+) and CF (-/-), murine siblings. Gender-matched juvenile +/+ and -/- litter mates were lyophilized and placed in a BN capsule to reduce thermal-neutron activation and irradiated for 10 seconds at φ fast ∼ 1 x 10 13 n x cm -2 x s -1 using the MURR pneumatic-tube facility. Phosphorus was measured via the 31 P 15 (n,α) 28 Al 13 reaction. After several days decay, the whole-body specimens were re-irradiated in the same facility, but without thermal-neutron shielding, for 5 seconds and the gamma-ray spectrum was recorded at two different decay periods allowing measurement of 77m Se, 24 Na, 27m g, 38 Cl, 42k , 49 Ca, 56 Mn, 66 Cu and 80 Br from the corresponding radiative-capture reactions. (author)

  20. Simplified calibration and evaluation procedures for improvised whole body gamma spectrometry in emergency situations

    International Nuclear Information System (INIS)

    Malatova, I.; Bucina, I.; Drabova, D.; Cespirova, I.

    2000-01-01

    A semiconductor gamma spectrometer could be used for the rapid estimation of internal contamination of the people in cases of accidents even when no special calibration for whole body counting is prepared. Generic transfer factors for calculation of the whole body detection efficiency from the 25 cm distant point source detection efficiency are presented. Generic dependence of parameters of power function describing the detector efficiency for point source in 25 cm on the detector relative efficiency given by producer was derived from calibration of 18 detectors with relative efficiency from 1.4% to 62%. Minimum detectable activity for various backgrounds and the uncertainty of the estimate of whole body retention are presented, too. (author)

  1. An estimate of the radiation-induced cancer risk from the whole-body stray radiation exposure in neutron radiotherapy

    International Nuclear Information System (INIS)

    Geraci, J.P.; Jackson, K.L.; Mariano, M.S.

    1982-01-01

    1980 BEIR III risk factors have been used to estimate the secondary cancer risks from the whole-body stray radiation exposures occurring in neutron radiotherapy. Risks were calculated using linear, linear-quadratic and quadratic dose-response models for the gamma component of the stray radiation. The linear dose-response model was used to calculate risk for the neutron component of the stray radiation. These estimates take into consideration for the first time the age and sex distribution of patients undergoing neutron therapy. Changes in risk as a function of the RBE (10-100) assigned to the stray neutron radiation component have also been assessed. Excess risks in neutron-treated patients have been compared with excess risks for photon-treated patients and with the expected incidence of cancer in a normal population having the same age and sex distribution. Results indicate that it will be necessary to tolerate a higher incidence of secondary cancers in patients undergoing fast neutron therapy than is the case with conventional photon therapy. For neutron RBEs of less than 50 the increased risk is only a fraction of the normal expected incidence of cancer in this population. Comparison of the radiation-induced risk with reported normal tissue complication rates in the treatment volume indicates that the excess cancer risk is substantially lower than the risk from other late normal tissue effects. (author)

  2. Acute effects of whole body gamma irradiation on exocrine pancreatic secretion in the pig

    International Nuclear Information System (INIS)

    Monti, P.; Scanff, P.; Joubert, C.; Vergnet, M.; Grison, S.; Griffiths, N.

    2004-01-01

    Reports on radiation damage to the pancreas deal essentially with long-term morphological changes with few data on pancreatic exocrine function. The aim of this work was to study the acute effects of whole body irradiation on volume and enzyme activities in the pancreatic juice. A whole body gamma irradiation (6 Gy) was investigated in pigs with continuous sampling of pancreatic juice before and after exposure via an indwelling catheter in the pancreatic duct. For each sample collected, total protein concentration and enzyme activities of trypsin, chymotrypsin, elastase, lipase and amylase were determined. Pancreatic juice volume was monitored during all periods of collection. The volume of pancreatic juice secreted daily decreased one day after irradiation and remained lower than the control values over the experimental period. Total proteins secreted in the pancreatic juice and total activities of pancreatic enzymes were reduced similarly. On the other hand, only specific activities of elastase and lipase were affected by irradiation. Whole body gamma irradiation resulted in a rapid and marked decrease of exocrine pancreatic secretion, in terms of volume as well as secreted enzymes. This may contribute in part to the intestinal manifestations of the acute and/or late radiation syndrome. (author)

  3. Caffeine protects mice against whole-body lethal dose of {gamma}-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    George, K.C.; Hebbar, S.A.; Kale, S.P.; Kesavan, P.C. [Biosciences Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    1999-06-01

    Administration of caffeine (1,3,7-trimethylxanthine), a major component of coffee, to Swiss mice at doses of 80 or 100 mg/kg body weight 60 min prior to whole-body lethal dose of {gamma}-irradiation (7.5 Gy) resulted in the survival of 70 and 63% of animals, respectively, at the above doses in contrast to absolutely no survivors (LD-100/25 days) in the group exposed to radiation alone. Pre-treatment with a lower concentration of caffeine (50 mg/kg) did not confer any radioprotection. The protection exerted by caffeine (80 mg/kg), however, was reduced from 70 to 50% if administered 30 min prior to irradiation. The trend statistics reveal that a dose of 80 mg/kg administered 60 min before whole-body exposure to 7.5 Gy is optimal for maximal radioprotection. However, caffeine (80 mg/kg) administered within 3 min after irradiation offered no protection. While there is documentation in the literature that caffeine is an antioxidant and radioprotector against the toxic pathway of radiation damage in a wide range of cells and organisms, this is the first report demonstrating unequivocally its potent radioprotective action in terms of survival of lethally whole-body irradiated mice. (author)

  4. Caffeine and Aspirin Protecting Albino Rats A gainst Biochemical and Histological Disorders Induced by Whole Body Gamma Irradiation

    International Nuclear Information System (INIS)

    Abd El-Rahman, N.A.; Sherif, N.H.

    2015-01-01

    Caffeine is an alkaloid (purine derivative) that contains flavonoids, where as aspirin, natural component of mammalian tissue ( acetylsalicylic acid) is one of the most commonly used non steroidal anti - inflammatory , and it is a necessary factor in the utilization of long - chain fatty acids to produce energy. Furthermore, it has been shown to protect cells from per oxidative stress. Th e objective of the present study is to evaluate the efficacy of caffeine (1,3,7 - trimethyl xanthine) 80 mg/kg b.wt. a nd aspirin ( acetylsalicylic acid) in the amelioration of the physiological and histological changes in stomach and intestine of rats exposed to gamma irradiation . Male albino rats were divided into 8 groups. 1 - Control group: rats not subject to any treatment, 2 - Caffeine group: rats received caffeine ( 80 ml/Kg body weight )via intraperitoneal injection for 21 days, 3 - Aspirin group: rats received aspirin (150 mg / kg body) via intraperitoneal injection for 21 days , 4 - Caffeine + Aspirin group: rats received caffeine a nd aspirin treatment, 5 - Radiation groups: rats were whole body gamma irradiated at 8 Gy , 6 - Caffeine + Radiation group: rats received caffeine for 21 days before whole body gamma irradiation at 8 Gy, 7 - Aspirin + Radiation group: rats received aspirin during 21 days before w hole body gamma irradiation , 8 - Caffeine + Aspirin + Radiation group: rats received caffeine parallel to aspirin for 21 days before whole body gamma irradiation. Animals were sacrificed 24 hrs post irradiation. The results demonstrated that rats exposed to whole body gamma irradiation showed a significant increase in alanine amino transferase (AL ) , aspartate amino transferase ( AST), and alkaline phosphatase (ALP) activities, and a significant decrease in total protein indicating liver injury. A significant increase in urea, creatinine, Na + ,and K + were recorded indicating kidney damage. Alteration of liver and kidney functions was accompanied by a significant

  5. Protective Role Of Fresh Pomegranate Against Oxidative Damage In Whole Body Gamma Irradiated Male Albino Rats

    International Nuclear Information System (INIS)

    Kassab, F.M.A.; Taha, M.S.

    2013-01-01

    Twenty four male albino rats, body weight 100-130 g, were used to evaluate the protective role of fresh pomegranate fruit intake for 30 days on the damage induced by single dose of 6 Gy whole body gamma irradiation. The rats were randomly and equally divided into four groups: group (1): control, group (2): irradiated with 6 Gy, group (3): pomegranate for 30 days and group (4): pomegranate for 30 days followed by 6 Gy whole body irradiation. At the end of the experiment, all rats were sacrificed after 12 hours fasting then sera were separated for the determination of sugar, total antioxidant, lipid profile and liver and kidney functions. Results showed that gamma radiation caused significant decline (P<0.05) in serum total antioxidant, total protein, albumin, HDL-C and blood glucose with significant elevation (P<0.05) in other hepato-renal markers in addition to serum total cholesterol, triglycerides and LDL-C. These changes were significantly attenuated in irradiated animals pre-treated with whole fresh pomegranate fruit leading to the conclusion that pre-intake of pomegranate fruit had a radio- protective effect. This protection of this whole fruit may be due to the increased total antioxidant level leading to free radical scavenging

  6. The unusual gamma-ray burst GRB 101225A explained as a minor body falling onto a neutron star.

    Science.gov (United States)

    Campana, S; Lodato, G; D'Avanzo, P; Panagia, N; Rossi, E M; Della Valle, M; Tagliaferri, G; Antonelli, L A; Covino, S; Ghirlanda, G; Ghisellini, G; Melandri, A; Pian, E; Salvaterra, R; Cusumano, G; D'Elia, V; Fugazza, D; Palazzi, E; Sbarufatti, B; Vergani, S D

    2011-11-30

    The tidal disruption of a solar-mass star around a supermassive black hole has been extensively studied analytically and numerically. In these events, the star develops into an elongated banana-shaped structure. After completing an eccentric orbit, the bound debris falls into the black hole, forming an accretion disk and emitting radiation. The same process may occur on planetary scales if a minor body passes too close to its star. In the Solar System, comets fall directly into our Sun or onto planets. If the star is a compact object, the minor body can become tidally disrupted. Indeed, one of the first mechanisms invoked to produce strong gamma-ray emission involved accretion of comets onto neutron stars in our Galaxy. Here we report that the peculiarities of the 'Christmas' gamma-ray burst (GRB 101225A) can be explained by a tidal disruption event of a minor body around an isolated Galactic neutron star. This would indicate either that minor bodies can be captured by compact stellar remnants more frequently than occurs in the Solar System or that minor-body formation is relatively easy around millisecond radio pulsars. A peculiar supernova associated with a gamma-ray burst provides an alternative explanation.

  7. Designing a new type of neutron detector for neutron and gamma-ray discrimination via GEANT4

    International Nuclear Information System (INIS)

    Shan, Qing; Chu, Shengnan; Ling, Yongsheng; Cai, Pingkun; Jia, Wenbao

    2016-01-01

    Design of a new type of neutron detector, consisting of a fast neutron converter, plastic scintillator, and Cherenkov detector, to discriminate 14-MeV fast neutrons and gamma rays in a pulsed n–γ mixed field and monitor their neutron fluxes is reported in this study. Both neutrons and gamma rays can produce fluorescence in the scintillator when they are incident on the detector. However, only the secondary charged particles of the gamma rays can produce Cherenkov light in the Cherenkov detector. The neutron and gamma-ray fluxes can be calculated by measuring the fluorescence and Cherenkov light. The GEANT4 Monte Carlo simulation toolkit is used to simulate the whole process occurring in the detector, whose optimum parameters are known. Analysis of the simulation results leads to a calculation method of neutron flux. This method is verified by calculating the neutron fluxes using pulsed n–γ mixed fields with different n/γ ratios, and the results show that the relative errors of all calculations are <5%. - Highlights: • A neutron detector is developed to discriminate 14-MeV fast neutrons and gamma rays. • The GEANT4 is used to optimize the parameters of the detector. • A calculation method of neutron flux is established through the simulation. • Several n/γ mixture fields are simulated to validate of the calculation method.

  8. Modulator Effect of Turmeric on Oxidative Damage in Whole Body Gamma Irradiated rats

    International Nuclear Information System (INIS)

    Amin, H.H.; Abdou, M.I.

    2012-01-01

    Because of its penetrating power and its ability to travel great distances, gamma rays are considered the primary hazard to the population during most radiological emergencies. So, there is a need to develop medical countermeasures to protect the first responders and remediation workers from biomedical effect of ionizing radiation. Turmeric has been reported to have many beneficial health effects, including a strong anti-oxidant effect, anti-inflammatory and anti-microbial properties. In the present study, turmeric was investigated as a therapeutic agent against hazards induced by ionizing radiation on kidney, liver, urinary and serum calcium levels and blood counts. A daily dose of 0.5 g/kg body weight was used in whole body gamma irradiated female rats with 3 Gy. Radiation effects were followed up for four weeks post irradiation. The results revealed that the administration of turmeric post-irradiation resulted in a significant inhibition in the frequency of radiation induced oxidative damage. It could be concluded that definite turmeric dose exerts a vital modulator role against gamma irradiation hazard

  9. Effects of chronic whole-body gamma irradiation on cell mediated immunity

    International Nuclear Information System (INIS)

    Shifrine, M.; Taylor, N.J.; Wilson, F.D.; DeRock, E.W.; Wiger, N.

    1979-01-01

    The whole blood lymphocyte stimulation test has been used to estimate the effects of chronic, whole-body, gamma irradiation in the dog. At lower dose levels, 0.07 and 0.33 R/day to cumulative dose of about 50 and 250 R, there was no change in cell mediated immunity. Dogs at high dose levels were affected. Dogs which succumbed to aplastic anemia at high doses had reduced immunological responses. Dogs which survived these high doses showed a temporary depression. When aplastic anemia was initially noted, there was a differential response to PHA and Con-A stimulation. The response to the former mitogen was profoundly reduced, but Con-A stimulated cells were unaffected, indicative of the development of radioresistant cell lines. As the dogs progressed toward aplastic anemia, all T lympocytes were negatively affected

  10. Biochemical and histological changes in whole body gamma-irradiated rats feed on wheat, barely and corn bran

    International Nuclear Information System (INIS)

    Soliman, S.M.; Hassan, A.A.; Ragab, E.A.

    2003-01-01

    The present work aims to study the effect of adding 3 different of dietary fibers (wheat, barley or corn bran) to normal balanced diet on liver function, blood, cholesterol, triglycerides and blood glucose level to counteract their elevation in whole body gamma irradiation rats. The experimental diets (balanced diet + fibre additive) were fed for 4 weeks. Samples (blood and tissue) were collected at intervals of times 7, 14 and 28 days post exposure to single dose (7 Gy) gamma irradiation. The control group consumed a fibre diet for 4 weeks, but not irradiated. The minimum aspartate amino-transferase (AST) and alanine aminotransferase (ALT) activities and the lowest blood total cholestrol, triglycerides and blood glucose were observed in rats (irradiated and non-irradiated rats) fed on wheat bran experimental diet (barley or corn bran). It could be concluded that wheat fibers were more effective, as compared with other fibers contained in balanced diet, in improving the investigated parameters observed after whole body gamma irradiation exposure

  11. Effects of whole-body gamma irradiation on oxygen transport by rat erythrocytes

    International Nuclear Information System (INIS)

    Thiriot, Christian; Kergonou, J.F.; Rocquet, Guy; Allary, Michel; Saint-Blancard, Jacques

    1982-01-01

    In this work, we studied the influence of whole-body gamma irradiation (8 Gy) upon oxygen transport by erythrocytes, through the erythrocyte count and related parameters, and through the factors affecting the oxygen affinity of hemoglobin. The oxygen affinity of hemoglobin is increased from day D + 5 after irradiation, and a severe erythropenia develops from day D + 8. These modifications probably result in tissue hypoxia via diminished oxygen transport from lungs to tissues, and decreased oxygen release from oxyhemoglobin in tissues

  12. In vivo Prompt Gamma Neutron Activation Analysis Facility for Total Body Nitrogen and Cd

    International Nuclear Information System (INIS)

    Munive, Marco; Revilla, Angel; Solis, Jose L.

    2007-01-01

    A Prompt Gamma Neutron Activation Analysis (PGNAA) system has been designed and constructed to measure the total body nitrogen and Cd for in vivo studies. An aqueous solution of KNO 3 was used as phantom for system calibration. The facility has been used to monitor total body nitrogen (TBN) of mice and found that is related to their diet. Some mice swallowed diluted water with Cl 2 Cd, and the presence of Cd was detected in the animals. The minimum Cd concentration that the system can detect was 20 ppm

  13. Protective Effect Of Avocado Oil Against Biochemical And Histological Changes In Whole Body Gamma Irradiation In Albino Rats

    International Nuclear Information System (INIS)

    Abd El-Rahman, N.A.; Abd El Azime, A.SH.; Sherif, N.H.

    2013-01-01

    Avocado oil, extracted from the pulp of the fruit, is rich in poly-unsaturated fatty acids, linoleic, linolenic, oleic acids and the monounsaturated fatty acid. It also contains B-sitosterol, B-carotene, lecithin, minerals and vitamins A, C, D and E. Avocado oil lowers the blood levels of serum lipids and has antioxidant properties as a free radical scavenger. Male albino rats were divided into 5 groups. 1- Control group: rats not subjected to any treatment, 2- Avocado treated group: rats received avocado oil (0.1 ml/kg/day) via intraperitoneal injection during 21 days, 3- Irradiated group: rats were whole body gamma irradiated with 7 Gy, 4- Avocado + irradiated group: rats received avocado oil for 21 days then exposed to whole body gamma irradiation with 7 Gy and 5- Radiation + avocado group: rats were exposed to 7 Gy whole body gamma irradiation then received avocado oil for 21 days. Avocado oil (0.1 ml/kg/day) was given to rats, receiving a standard diet, for 21 days before exposure to 7 Gy whole body gamma irradiation then the treatment was continued for 10 days after irradiation. Several investigations were carried out such as superoxide dismutase (SOD), malondialdehyde (MDA), reduced glutathione (GSH), catalase (CAT), lipid profile and blood sugar. High significant increase in MDA was observed and treatment with avocado before irradiation caused significant increase in GSH, CAT and SOD and significant decrease in MDA as compared to the irradiated groups. The results also showed that treatment with avocado oil significantly diminished the radiation-induced alterations observed in the levels of lipid profile and glucose. The results demonstrated that whole body gamma irradiated rats showed significant increase in alanine aminotransferase (ALT), aspartate amino-transferase (AST), alkaline phosphatase (ALP) and glucose. By studying the lipid profile, significant increases in cholesterol, triglycerides and LDL-C levels were recorded while significant decrease was

  14. Catecholamine levels in sheep hypothalamus, hypophysis and adrenals following whole-body gamma irradiation

    International Nuclear Information System (INIS)

    Pastorova, B.; Arendarcik, J.; Molnarova, M.

    1985-01-01

    Changes were studied in the levels of catecholamines and L-DOPA in the control system of the reproduction cycle (hypothalamus, hypophysis) and in the adrenal glands of sheep after whole-body irradiation with 60 Co at a total dose of 6.7 Gy for seven days. The output of the radiation source was 0.039 Gy/h. The catecholamines (noradrenaline, dopamine and adrenaline) and L-DOPA were determined after separation from the tissues by the method of spectral fluorometry. After whole-body exposure to gamma radiation, noradrenaline dropped in the hypothalamus in comparison with the control group, most significantly in the rostral (by 74.2%) and caudal (by 40%) parts. A similar drop was also observed in dopamine, the concentrations of which decreased in the rostral hypothalamus by 60%. Adrenaline showed a drop in the hypothalamus, most significant in the caudal region (by 62%). Consequently, the level of the precursor of the synthesis of catecholamines and L-DOPA changed and showed in the studied regions of the hypothalamus significantly lower levels than in the control group. As regards the hypophysis, after irradiation no significant changes in the levels of noradrenaline and adrenaline were recorded, however, dopamine and L-DOPA dropped significantly (P<0.01). The exposure to gamma radiation also causes a decrease in the concentrations of catecholamines and L-DOPA in the adrenal glands of sheep, most significantly in noradrenaline (by 61%). It was thus found that whole-body irradiation of sheep with a dose of 6.7 Gy results in a significant decrease in the level of catecholamines in the hypothalamus, hypophysis and adrenal glands, which is probably in relation to the failure of synthesis and degradation of catecholamines and to the total organism injury

  15. Radioprotection by caffeine pre-treatment and post-treatment in the bone marrow chromosomes of mice given whole-body [gamma]-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Farooqi, Z.; Kesavan, P.C. (Jawaharlal Nehru Univ., New Delhi (India). School of Life Sciences)

    1992-10-01

    The effect of caffeine given as pre- and post-treatment in mice exposed to whole-body [gamma]-irradiation (1.5 Gy [sup 60]Co [gamma]-rays) was studied. The pre-treatment was either acute or chronic. The acute dose (5 mg/kg and 15 mg/kg body weight) was in the form of an injection given intraperitoneally, 30 min before irradiation. The chronic administration was in the form of caffeine solution (4.208x10[sup -3] M and 7.72x10[sup -4] M) contained in drinking water for 5 weeks prior to radiation exposure. The acute pre-treatment with caffeine reduced the radiation-induced frequency of chromosomal aberrations discernibly, whereas chronic pre-treatment afforded a much more significant degree of radioprotection. The caffeine post-treatment (5 mg/kg and 15 mg/kg body weight) was given in the form of an intraperitoneal injection to the mice immediately following whole-body [gamma]-irradiation. It is noted that both post-treatment concentrations of caffeine also significantly reduced the frequency of chromosomal aberrations induced by [gamma]-rays. These data are briefly discussed in terms of possible mechanistic considerations. (author). 33 refs.; 3 tabs.

  16. Whole body imaging

    International Nuclear Information System (INIS)

    de Luca, P.C.; Stoddart, H.F.; Jeffries, D.

    1976-01-01

    A whole body imaging system rapidly forms a quality image of the bony structure, soft tissue or specific organs of a patient who has been injected with a suitable radioactive tracer chemical. A radiation detector head assembly includes a number of detector subassemblies, each having a lead collimator with tapered holes for admitting gamma radiation from a small area of the patient to a scintillation crystal that converts the gamma rays admitted by the collimator into visible or ultraviolet energy pulses. A photomultiplier converts these pulses into electrical pulses. A row of equally spaced detector subassemblies reciprocate within a nonreciprocating lead shield along the long axis of the array over a distance substantially equal to the separation between adjacent ones of the small areas. Associated electronic and electromechanical apparatus control the reciprocating motion and the longitudinal motion of the radiation detector head assembly, and process the photodetected signals to produce in a relatively short time a visible image of the radiant energy emanating from the whole body of the patient scanned

  17. Simulated and measured neutron/gamma light output distribution for poly-energetic neutron/gamma sources

    Science.gov (United States)

    Hosseini, S. A.; Zangian, M.; Aghabozorgi, S.

    2018-03-01

    In the present paper, the light output distribution due to poly-energetic neutron/gamma (neutron or gamma) source was calculated using the developed MCNPX-ESUT-PE (MCNPX-Energy engineering of Sharif University of Technology-Poly Energetic version) computational code. The simulation of light output distribution includes the modeling of the particle transport, the calculation of scintillation photons induced by charged particles, simulation of the scintillation photon transport and considering the light resolution obtained from the experiment. The developed computational code is able to simulate the light output distribution due to any neutron/gamma source. In the experimental step of the present study, the neutron-gamma discrimination based on the light output distribution was performed using the zero crossing method. As a case study, 241Am-9Be source was considered and the simulated and measured neutron/gamma light output distributions were compared. There is an acceptable agreement between the discriminated neutron/gamma light output distributions obtained from the simulation and experiment.

  18. A simple neutron-gamma discriminating system

    International Nuclear Information System (INIS)

    Liu Zhongming; Xing Shilin; Wang Zhongmin

    1986-01-01

    A simple neutron-gamma discriminating system is described. A detector and a pulse shape discriminator are suitable for the neutron-gamma discriminating system. The influence of the constant fraction discriminator threshold energy on the neutron-gamma resolution properties is shown. The neutron-gamma timing distributions from an 241 Am-Be source, 2.5 MeV neutron beam and 14 MeV neutron beam are presented

  19. Neutron-induced gamma-ray spectroscopy: simulations for chemical mapping of planetary surfaces

    International Nuclear Information System (INIS)

    Brueckner, J.; Waenke, H.; Reedy, R.C.

    1986-01-01

    Cosmic rays interact with the surface of a planetary body and produce a cascade of secondary particles, such as neutrons. Neutron-induced scattering and capture reactions play an important role in the production of discrete gamma-ray lines that can be measured by a gamma-ray spectrometer on board of an orbiting spacecraft. These data can be used to determine the concentration of many elements in the surface of a planetary body, which provides clues to its bulk composition and in turn to its origin and evolution. To investigate the gamma rays made by neutron interactions, thin targets were irradiated with neutrons having energies from 14 MeV to 0.025 eV. By means of foil activation technique the ratio of epithermal to thermal neutrons was determined to be similar to that in the Moon. Gamma rays emitted by the targets and the surrounding material were detected by a high-resolution germanium detector in the energy range of 0.1 to 8 MeV. Most of the gamma-ray lines that are expected to be used for planetary gamma-ray spectroscopy were found in the recorded spectra and the principal lines in these spectra are presented. 58 refs., 7 figs., 9 tabs

  20. Neutron activation probe for measuring the presence of uranium in ore bodies

    International Nuclear Information System (INIS)

    Goldstein, N.P.; Smith, R.C.

    1979-01-01

    A neutron activation proble comprises a pulsed neutron source in series with a plurality of delayed neutron detectors for measuring radioactivity in a well borehole together with a NaI (Tl) counter for measuring the high energy 2.62 MeV gamma line from thorium. The neutron source emits neutrons which produce fission in uranium and thorium in the ore body and the delayed neutron detectors measure the delayed neutrons produced from such fission while the NaI (Tl) counter measures the 2.62 MeV gamma line from the undisturbed thorium in the ore body. The signal from the NaI (Tl) counter is processed and subtracted from the signal from the delayed neutron detectors with the result being indicative of the amount of uranium present in the ore body

  1. Calibration of the delayed-gamma neutron activation facility

    International Nuclear Information System (INIS)

    Ma, R.; Zhao, X.; Rarback, H.M.; Yasumura, S.; Dilmanian, F.A.; Moore, R.I.; Lo Monte, A.F.; Vodopia, K.A.; Liu, H.B.; Economos, C.D.; Nelson, M.E.; Aloia, J.F.; Vaswani, A.N.; Weber, D.A.; Pierson, R.N. Jr.; Joel, D.D.

    1996-01-01

    The delayed-gamma neutron activation facility at Brookhaven National Laboratory was originally calibrated using an anthropomorphic hollow phantom filled with solutions containing predetermined amounts of Ca. However, 99% of the total Ca in the human body is not homogeneously distributed but contained within the skeleton. Recently, an artificial skeleton was designed, constructed, and placed in a bottle phantom to better represent the Ca distribution in the human body. Neutron activation measurements of an anthropomorphic and a bottle (with no skeleton) phantom demonstrate that the difference in size and shape between the two phantoms changes the total body calcium results by less than 1%. To test the artificial skeleton, two small polyethylene jerry-can phantoms were made, one with a femur from a cadaver and one with an artificial bone in exactly the same geometry. The femur was ashed following the neutron activation measurements for chemical analysis of Ca. Results indicate that the artificial bone closely simulates the real bone in neutron activation analysis and provides accurate calibration for Ca measurements. Therefore, the calibration of the delayed-gamma neutron activation system is now based on the new bottle phantom containing an artificial skeleton. This change has improved the accuracy of measurement for total body calcium. Also, the simple geometry of this phantom and the artificial skeleton allows us to simulate the neutron activation process using a Monte Carlo code, which enables us to calibrate the system for human subjects larger and smaller than the phantoms used as standards. copyright 1996 American Association of Physicists in Medicine

  2. Hypodontia in the beagle after perinatal whole-body 60Co gamma irradiation

    International Nuclear Information System (INIS)

    Lee, A.C.; Angleton, G.M.; Benjamin, S.A.

    1989-01-01

    As part of a long-term study to evaluate health effects of pre- and postnatal irradiation, dental development was examined. Beagles were irradiated in utero at 8, 28, or 55 days postcoitus or postnatally at 2, 70, or 365 days postpartum. Whole-body 60 Co gamma radiation doses ranged from 0 to 3.8 Gy. There was an age-dependent dose-related increase in premolar hypodontia for animals irradiated at 55 days postcoitus or 2 days postpartum with doses of 0.83 Gy or higher and for those irradiated at 28 days postcoitus with 1.2 Gy or higher

  3. Epinephrine ameliorating response of serum proteins and protein fractions to whole body gamma irradiation in albino rats

    International Nuclear Information System (INIS)

    Mohamed, M.A.; Saada, H.N.; Roushdy, H.M.; Awad, O.M.; El-Sayed, M.M.; Azab, Kh.Sh.

    1997-01-01

    The present study was carried out to investigate the role of epinephrine in modifying the radiation induced effects on serum protein as presented by total protein, protein fractions and albumin/globulin (A/G) ratio in adult albino rats. Epinephrine was intraperitoneally injected at a concentration of 200 M/g body weight, 15 min, pre-9 or just after 0 whole body gamma-irradiation of rats at a dose of 6 Gy (single dose). Studies have been undertaken at periods of 1 hr, 4 hrs, 1,3 and 7 days after irradiation. Data of the present study revealed that whole body gamma-irradiation induced significant decreased in the total content of serum protein and albumin at 1,3 and 7 days post radiation exposure alpha 1-globulin significantly increased only on the 1 st hr post-irradiation, however alpha 1-globulin significantly increased along all the experimental periods. B-globulin insignificantly changed after irradiation but gamma-globulin significantly decreased during the experimental periods. These changes were associated with significant decreases in A/G ratio at 3 and 7 days post-irradiation. Administration of epinephrine pre-or after radiation exposure produced some amelioration in the radiation induced changes in the studied parameters. So, it could be concluded that epinephrine plays a beneficial radioprotective role through its pharmacologic properties

  4. Enhancement recovery of haemostatic system by tocopherol-monoglucoside (TMG) in whole body gamma irradiated rats

    International Nuclear Information System (INIS)

    Elshamy, E.

    2007-01-01

    A preparation of α-tocopherol monoglucoside (TMG) administered intraperitoneally (i.p.) at a dose of 600 mg/kg body wt immediately after whole body gamma-irradiation was examined for its radioprotective efficacy towards some haemostatic parameters (protein C, antithrombin III and tissue plasminogen activators). When rats received gamma-rays at a dose of 6.0 Gy, a marked decrease in plasma protein C and antithrombin 111 activities within the early post-irradiated period was observed. On the other hand, increase in tissue plasminogen activators had been found. Accordingly, whole body y-radiation was found to modulate the coagulation system by down regulating the expression of activated protein C (APC), antithrombins and induction of the fibrinolytic systems by hyper regulating the tissue plasminogen activators, modifying in this way, the balance between pro coagulant and anticoagulant activities and so disturbing the homeostasis. This may lead to micro circulatory disturbance, which plays a role in ischemic organ dysfunction. However, these changes were attenuated in TMG-treated mice. Significant protection of the previous parameters was found for the TMG group of rats. The return to normal value of the reduced protein C and antithrombin Ill starting from the 5th day and the increased plasminogen activators starting from the 12 h interval were less in TMG-treated rats than in untreated irradiated rats. Accordingly, TMG administration was found to enhance haemostatic recovery

  5. Gene Expression Changes in Mouse Intestinal Tissue Following Whole-Body Proton or Gamma-Irradiation

    Science.gov (United States)

    Purgason, Ashley; Zhang, Ye; Mangala, Lingegowda; Nie, Ying; Gridley, Daila; Hamilton, Stanley R.; Seidel, Derek V.; Wu, Honglu

    2014-01-01

    Crew members face potential consequences following exposure to the space radiation environment including acute radiation syndrome and cancer. The space radiation environment is ample with protons, and numerous studies have been devoted to the understanding of the health consequences of proton exposures. In this project, C57BL/6 mice underwent whole-body exposure to 250 MeV of protons at doses of 0, 0.1, 0.5, 2 and 6 Gy and the gastrointestinal (GI) tract of each animal was dissected four hours post-irradiation. Standard H&E staining methods to screen for morphologic changes in the tissue showed an increase in apoptotic lesions for even the lowest dose of 0.1 Gy, and the percentage of apoptotic cells increased with increasing dose. Results of gene expression changes showed consistent up- or down- regulation, up to 10 fold, of a number of genes across exposure doses that may play a role in proton-induced oxidative stress including Gpx2. A separate study in C57BL/6 mice using the same four hour time point but whole-body gamma-irradiation showed damage to the small intestine with lesions appearing at the smallest dose of 0.05 Gy and increasing with increasing absorbed dose. Expressions of genes associated with oxidative stress processes were analyzed at four hours and twenty-four hours after exposure to gamma rays. We saw a much greater number of genes with significant up- or down-regulation twenty-four hours post-exposure as compared to the four hour time point. At both four hours and twenty-four hours post-exposure, Duox1 and Mpo underwent up-regulation for the highest dose of 6 Gy. Both protons and gamma rays lead to significant variation in gene expressions and these changes may provide insight into the mechanism of injury seen in the GI tract following radiation exposure. We have also completed experiments using a BALB/c mouse model undergoing whole-body exposure to protons. Doses of 0, 0.1, 1 and 2 Gy were used and results will be compared to the work mentioned

  6. From whole-body counting to imaging: The computer aided collimation gamma camera project (CACAO)

    Energy Technology Data Exchange (ETDEWEB)

    Jeanguillaume, C.; Begot, S.; Quartuccio, M.; Douiri, A.; Ballongue, P

    2000-07-01

    Whole-body counting is the method of choice for in vivo detection of contamination. To extend this well established method, the possible advantages of imaging radiocontaminants are examined. The use of the CACAO project is then studied. A comparison of simulated reconstructed images obtained by the CACAO project and by a conventional gamma camera used in nuclear medicine follows. Imaging a radionuclide contaminant with a geometrical sensitivity of 10{sup -2} seems possible in the near future. (author)

  7. From whole-body counting to imaging: The computer aided collimation gamma camera project (CACAO)

    International Nuclear Information System (INIS)

    Jeanguillaume, C.; Begot, S.; Quartuccio, M.; Douiri, A.; Ballongue, P.

    2000-01-01

    Whole-body counting is the method of choice for in vivo detection of contamination. To extend this well established method, the possible advantages of imaging radiocontaminants are examined. The use of the CACAO project is then studied. A comparison of simulated reconstructed images obtained by the CACAO project and by a conventional gamma camera used in nuclear medicine follows. Imaging a radionuclide contaminant with a geometrical sensitivity of 10 -2 seems possible in the near future. (author)

  8. Prompt and delay gamma ray measurements for 'in vivo' neutron activation analysis using a cyclic system

    International Nuclear Information System (INIS)

    Matthews, I.P.

    1979-09-01

    Early attempts at determining the elemental composition of the body by radioactive isotope dilution techniques are reviewed. The development and current status of in-vivo neutron activation analysis and the ways in which it supersedes or supplements certain of the former techniques are outlined. An irradiation facility is described which employs a 5 Ci neutron source and is capable of performing prompt and delay γ-ray measurements as well as cyclic activation. The uniformity of thermal neutron flux in a phantom is demonstrated and the neutron spectrum at a depth in the phantom has been obtained by means of threshold detectors. An examination is made of the possible applications of the Monte Carlo method to the design of irradiation and detection facilities and in yielding information about inaccessible areas. Detection limits for the bulk body elements and trace elements are presented. It is shown that the depth of a region of the body can be determined from a prompt gamma ray spectrum. This technique can be used to correct measurements when it is known that activation and detection is non-uniform. The feasibility of using a C.T. whole body scanner to measure bone demineralisation is explored. (author)

  9. 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.

  10. Changes in Serum Zinc, Copper and Ceruloplasmin Levels of Whole Body Gamma Irradiated Rats

    International Nuclear Information System (INIS)

    Abdou, M.I.; Shaban, H.A.; El Gohary, M.I.

    2011-01-01

    Rats are whole body irradiated with different Gamma radiation doses. Zinc and Copper, two important trace elements in the biological processes and Ceruloplasmin, a protein which carries more than 95% of serum Cu and has important roles in many vital processes are followed up in the irradiated rat sera. This work aimed to determine the changes in the serum levels of the three parameters (Zinc, Copper and Ceruloplasmin) through eight weeks follow up period (1st, 2nd, 3rd, 4th, 6th, and 8th week) post whole body gamma irradiation with three sub-lethal doses (2, 3.5 and 5 Gy) of rats. All the experimental animals did not receive any medical treatment. Zinc and Copper were measured using discrete nebulization flame atomic absorption spectrometry. Ceruloplasmin was measured using a colorimetric method. The statistical analyses of the results show that the Zinc levels of the irradiated groups decreased significantly post irradiation and then were recovered at the 6th week post irradiation. The Copper levels of the irradiated groups increased significantly and then were recovered at 6th week post irradiation. The levels of Ceruloplasmin in the same groups increased significantly throughout the whole follow up period. The conclusion is that, Zinc, Copper and Ceruloplasmin levels changed significantly in the irradiated groups compared to the control group with a maximum effect noted in the groups irradiated with the higher doses and that the lower dose irradiated groups recover earlier than the higher ones. Also the correlation between Copper and Zinc is reversible at different doses and that between Copper and Ceruloplasmin is direct

  11. Sesamol attenuates cytogenetic damages in bone marrow cells of whole body gamma irradiated mice

    International Nuclear Information System (INIS)

    Kumar, Arun; Tamizh Selvan, G.; Adhikari, Jawahar S.; Chaudhury, N.K.

    2014-01-01

    Whole body radiation exposure cause damages to all vital organs and bone marrow is the most sensitive. Pre-treatment with antioxidant as single prophylactic dose is expected to lower induction of damages in bone marrow. In the present study we have focused on sesamol, a dietary antioxidant mediated radioprotection in bone marrow cells of gamma irradiated mice and compared with melatonin. Male C57BL/6 mice were intraperitoneally administered with sesamol (10 and 20 mg/kg body) and after 30 minutes exposed to whole body gamma radiation using 60 Co Teletherapy unit. Mice were injected with 0.2 ml of a metaphase arresting agent (0.05% colchicine) intra-peritoneally 3 hours prior to sacrifice (24 hrs. post-irradiation). Bone marrow cells were flushed out from femurs of each animal and processed for chromosomal aberration assay. Another set of experiment without colchicine injection was performed to access the DNA damage in bone marrow using alkaline comet assay. At least 100 metaphases per animal were scored under light microscope to record various aberrations and total chromosomal aberrations (TCA) was calculated. Similar measurements were performed with melatonin for comparing the efficacy of sesamol. Gamma irradiation has increased the chromatid type aberrations (break formation, fragment) and chromosomal type aberrations (ring formation, acentric) in bone marrow cells. The results have shown significant (p< 0.001) increase in TCA of irradiated mice than control. While pre-treatment of sesamol and melatonin 10 mg/kg significantly (p<0.05) reduced the TCA. The extend of protection has increased at 20 mg/kg significantly (p<0.001) as evident from the reduced TCA compared to irradiated group. Interestingly, sesamol and melatonin have shown similar extent of reduction of TCA. Thus sesamol has demonstrated strong ability to protect bone marrow at low dosage. These investigations on sesamol mediated protection in bone marrow are likely to benefit development of

  12. Prompt-gamma neutron activation analysis system design: Effects of D-T versus D-D neutron generator source selection

    Science.gov (United States)

    Prompt-gamma neutron activation (PGNA) analysis is used for the non-invasive measurement of human body composition. Advancements in portable, compact neutron generator design have made those devices attractive as neutron sources. Two distinct generators are available: D-D with 2.5 MeV and D-T with...

  13. Quantitative whole body scintigraphy - a simplified approach

    International Nuclear Information System (INIS)

    Marienhagen, J.; Maenner, P.; Bock, E.; Schoenberger, J.; Eilles, C.

    1996-01-01

    In this paper we present investigations on a simplified method of quantitative whole body scintigraphy by using a dual head LFOV-gamma camera and a calibration algorithm without the need of additional attenuation or scatter correction. Validation of this approach to the anthropomorphic phantom as well as in patient studies showed a high accuracy concerning quantification of whole body activity (102.8% and 97.72%, resp.), by contrast organ activities were recovered with an error range up to 12%. The described method can be easily performed using commercially available software packages and is recommendable especially for quantitative whole body scintigraphy in a clinical setting. (orig.) [de

  14. Total proteins and protein fractions levels in pregnant rats subjected to whole-body gamma irradiation

    International Nuclear Information System (INIS)

    Mansour, M.A.; Roushdy, H.M.; Mazhar, F.M.; Abu-Gabal, H.A.

    1986-01-01

    A total number of 180 mature rats (120 females and 60 males) weighing from 120-140 g were used to study the effect of two doses (2 and 4 Gy) whole-body gamma irradiation on the level of total protein and protein fractions in serum of pregnant rats during the period of organogenesis. It was found that the levels of total protein, albumin and gamma globulins significantly decreased according to the doses of exposure. The levels of alpha and beta globulins significantly increased more in the serum of rats exposed to 2 Gy than in rats exposed to 4 Gy. The level of A/G ratio significantly decreased more in the serum of rats exposed to 2Gy than in those exposed to 4 Gy

  15. Next Generation Gamma/Neutron Detectors for Planetary Science., Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Gamma ray and neutron spectroscopy are well established techniques for determining the chemical composition of planetary surfaces, and small cosmic bodies such as...

  16. Neutron beam design for low intensity neutron and gamma-ray radioscopy using small neutron sources

    CERN Document Server

    Matsumoto, T

    2003-01-01

    Two small neutron sources of sup 2 sup 5 sup 2 Cf and sup 2 sup 4 sup 1 Am-Be radioisotopes were used for design of neutron beams applicable to low intensity neutron and gamma ray radioscopy (LINGR). In the design, Monte Carlo code (MCNP) was employed to generate neutron and gamma ray beams suited to LINGR. With a view to variable neutron spectrum and neutron intensity, various arrangements were first examined, and neutron-filter, gamma-ray shield and beam collimator were verified. Monte Carlo calculations indicated that with a suitable filter-shield-collimator arrangement, thermal neutron beam of 3,900 ncm sup - sup 2 s sup - sup 1 with neutron/gamma ratio of 7x10 sup 7 , and 25 ncm sup - sup 2 s sup - sup 1 with very large neutron/gamma ratio, respectively, could be produced by using sup 2 sup 5 sup 2 Cf(122 mu g) and a sup 2 sup 4 sup 1 Am-Be(37GBq)radioisotopes at the irradiation port of 35 cm from the neutron sources.

  17. Formation properties from high resolution neutron activation gamma-ray spectra

    International Nuclear Information System (INIS)

    Mellor, D.W.; Underwood, M.C.

    1985-01-01

    A neutron activation logging tool has been developed comprising a Five Curie /sup 241/ Am-Be neutron source and a large n-type hyper-pure germanium gamma-ray detector. The tool maintains a constant temperature cryogenic environment for periods in excess of twenty hours. No liquid nitrogen or other consumable material is used in the operating or recharging stages. A large calibration tank in simulated well-bore geometry has been constructed with sand bodies saturated with oil and low salinity water (14,000 ppm NaCl). In the water zone prompt neutron capture gamma-rays from silicon, hydrogen and chlorine were prominent; gamma-rays from inelastic scattering on oxygen and silicon were detected. No gamma-rays arising from inelastic scattering on carbon were detected. These data have been interpreted to yield the porosity, fluid saturations, salinity and matrix composition. In the oil zone, gamma-rays arising from inelastic scattering on oxygen, silicon and carbon were detected. The intensity of the carbon line was very poor, and inadequate for quantitative purposes

  18. Neutron-gamma discrimination of boron loaded plastic scintillator

    International Nuclear Information System (INIS)

    Wang Dong; He Bin; Zhang Quanhu; Wu Chuangxin; Luo Zhonghui

    2010-01-01

    Boron loaded plastic scintillator could detect both fast neutrons thanks to hydrogen and thermal neutrons thanks to 10B. Both reactions have large cross sections, and results in high detection efficiency of incident neutrons. However, similar with other organic scintillators, boron loaded plastic scintillator is sensitive to gamma rays and neutrons. So gamma rays must be rejected from neutrons using their different behavior in the scintillator. In the present research zero crossing method was used to test neutron-gamma discrimination of BC454 boron loaded plastic scintillator. There are three Gaussian peaks in the time spectrum, they are corresponding to gamma rays, fast neutrons and flow neutrons respectively. Conclusion could be made that BC454 could clear discriminate slow neutrons and gamma, but the discrimination performance turns poor as the neutrons' energy becomes larger. (authors)

  19. In vivo quantification of {sup 177}Lu with planar whole-body and SPECT/CT gamma camera imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Dale L. [Department of Nuclear Medicine, Royal North Shore Hospital, St Leonards, NSW 2065 (Australia); Faculty of Health Sciences, University of Sydney, Cumberland, NSW (Australia); Sydney Medical School, University of Sydney, Camperdown, NSW (Australia); NETwork, Sydney Vital, St Leonards, Sydney, NSW (Australia); Hennessy, Thomas M.; Willowson, Kathy P.; Henry, E. Courtney [Institute of Medical Physics, University of Sydney, Camperdown, NSW (Australia); Chan, David L.H. [Department of Nuclear Medicine, Royal North Shore Hospital, St Leonards, NSW 2065 (Australia); NETwork, Sydney Vital, St Leonards, Sydney, NSW (Australia); Aslani, Alireza [Department of Nuclear Medicine, Royal North Shore Hospital, St Leonards, NSW 2065 (Australia); Roach, Paul J. [Department of Nuclear Medicine, Royal North Shore Hospital, St Leonards, NSW 2065 (Australia); Sydney Medical School, University of Sydney, Camperdown, NSW (Australia)

    2015-09-17

    Advances in gamma camera technology and the emergence of a number of new theranostic radiopharmaceutical pairings have re-awakened interest in in vivo quantification with single-photon-emitting radionuclides. We have implemented and validated methodology to provide quantitative imaging of {sup 177}Lu for 2D whole-body planar studies and for 3D tomographic imaging with single-photon emission computed tomography (SPECT)/CT. Whole-body planar scans were performed on subjects to whom a known amount of [{sup 177}Lu]-DOTA-octreotate had been administered for therapy. The total radioactivity estimated from the images was compared with the known amount of the radionuclide therapy administered. In separate studies, venous blood samples were withdrawn from subjects after administration of [{sup 177}Lu]-DOTA-octreotate while a SPECT acquisition was in progress and the concentration of the radionuclide in the venous blood sample compared with that estimated from large blood pool structures in the SPECT reconstruction. The total radioactivity contained within an internal SPECT calibration standard was also assessed. In the whole-body planar scans (n = 28), the estimated total body radioactivity was accurate to within +4.6 ± 5.9 % (range −17.1 to +11.2 %) of the correct value. In the SPECT reconstructions (n = 12), the radioactivity concentration in the cardiac blood pool was accurate to within −4.0 ± 7.8 % (range −16.1 to +7.5 %) of the true value and the internal standard measurements (n = 89) were within 2.0 ± 8.5 % (range −16.3 to +24.2 %) of the known amount of radioactivity contained. In our hands, state-of-the-art hybrid SPECT/CT gamma cameras were able to provide accurate estimates of in vivo radioactivity to better than, on average, ±10 % for use in biodistribution and radionuclide dosimetry calculations.

  20. Prompt-gamma neutron activation analysis system design. Effects of D-T versus D-D neutron generator source selection

    International Nuclear Information System (INIS)

    Shypailo, R.J.; Ellis, K.J.

    2008-01-01

    Prompt-gamma neutron activation (PGNA) analysis is used for the non-invasive measurement of human body composition. Advancements in portable, compact neutron generator design have made those devices attractive as neutron sources. Two distinct generators are available: D-D with 2.5 MeV and D-T with 14.2 MeV neutrons. To compare the performance of these two units in our present PGNA system, we performed Monte Carlo simulations (MCNP-5; Los Alamos National Laboratory) evaluating the nitrogen reactions produced in tissue-equivalent phantoms and the effects of background interference on the gamma-detectors. Monte Carlo response curves showed increased gamma production per unit dose when using the D-D generator, suggesting that it is the more suitable choice for smaller sized subjects. The increased penetration by higher energy neutrons produced by the D-T generator supports its utility when examining larger, especially obese, subjects. A clinical PGNA analysis design incorporating both neutron generator options may be the best choice for a system required to measure a wide range of subject phenotypes. (author)

  1. Protection from radiation induced changes in liver and serum transaminase of whole body gamma irradiated rats

    International Nuclear Information System (INIS)

    Elkashef, H.S.; Roushdy, H.M.; Saada, H.N.; Abdelsamie, M.

    1986-01-01

    Whole body gamma irradiation of rats with a dose of 5.5 Gy induced significant changes in the activity of liver and serum transaminase. The results indicated that this radiation dose caused a significant increase in the activity of serum Got and GPT on the third and seventh days after irradiation. This was followed by significant decreases on the fourteenth post-irradiation day. The activity of Got returned to is control activity, while the activity of GPT was significantly above the control on the twenty ones post-irradiation day. The activity of Got, in the liver of irradiated rats was elevated during the post-irradiation days, but on the twenty one day activity was about the normal value. The activity of liver GPT firstly decreased and then increased very much but attained the control level on the fourteenth after irradiation. The intraperitoneal injection of testosterone-vitamin E mixture 10 days before whole body gamma irradiation caused complete recovery for the activity of liver and serum Got. No indication of remarkable recovery in the case of GPT activity was recorded either in liver or in serum of irradiated rats. The applied mixture could protect against radiation induced changes in Got activity of liver and serum but could not protect or ameliorate the changes which occurred in the activity of GPT of the two tissues. 2 tab

  2. EURADOS intercomparisons in external radiation dosimetry: similarities and differences among exercises for whole-body photon, whole-body neutron, extremity, eye-lens and passive area dosemeters

    International Nuclear Information System (INIS)

    Romero, Ana M.; Grimbergen, Tom; McWhan, Andrew; Stadtmann, Hannes; Fantuzzi, Elena; Clairand, Isabelle; Neumaier, Stefan; Dombrowski, Harald; Figel, Markus

    2016-01-01

    The European Radiation Dosimetry Group (EURADOS) has been organising dosimetry intercomparisons for many years in response to an identified requirement from individual monitoring services (IMS) for independent performance tests for dosimetry systems. The participation in intercomparisons gives IMS the opportunity to show compliance with their own quality management system, compare results with other participants and develop plans for improving their dosimetry systems. In response to growing demand, EURADOS has increased the number of intercomparisons for external radiation dosimetry. Most of these fit into the programme of self-financing intercomparisons for dosemeters routinely used by IMS. This programme is being coordinated by EURADOS working group 2 (WG2). Up to now, this programme has included four intercomparisons for whole-body dosemeters in photon fields, one for extremity dosemeters in photon and beta fields, and one for whole-body dosemeters in neutron fields. Other EURADOS working groups have organised additional intercomparisons including events in 2014 for eye-lens dosemeters and passive area dosemeters for environmental monitoring. In this paper, the organisation and achievements of these intercomparisons are compared in detail focusing on the similarities and differences in their execution. (authors)

  3. Cardiac ultrastructural changes in rats following 250 Gy whole body. gamma. -irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Guo; Mingyue, Zhu; Zhiqin, Zhao

    1985-10-01

    Sixteen rats were whole body irradiated with 250 Gy of /sup 60/Co ..gamma..-rays, killed at different intervals after exposure, and then observed by electron microscope. We found lysis of part of myofilaments in specimen obtained at 10 minutes after exposure, and resolution of Z-band at 30 minutes after exposure. These changes were more significant in sections at 12 hours postirradiation, but there also appeared cell regeneration at the same time. The vascular changes were more obvious with the endothelial cytoplasma projected in capillary lumen, nearly obstructing it. All of above described changes may be found in hematologic or intestinal forms of radiation sickness, but they must take place more late after exposure. In cardiovascular form, however, these changes were found as early as 10-30 minutes after exposure; this is a special feature helpful to diagnosis.

  4. 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

  5. Inhomogeneity of neutron and gamma-ray attenuation in biological shields

    Energy Technology Data Exchange (ETDEWEB)

    El-bakkoush, F A; El-Ghobary, A M; Megahid, R M [Reactor and Neutron physics Department, Nuclear Research Center, A.E.A., Cairo (Egypt)

    1997-12-31

    Measurements have been carried-out to investigate the attenuation properties of some materials which are used as biological shields around nuclear radiation sources. Investigation was performed by measuring the transmitted fast neutron and gamma-spectra through cylindrical samples of magnetite- limonite, steel and cellulose shields. The neutron and gamma spectra were measured by a neutron-gamma spectrometer with stilbene scintillator. Discrimination between neutron and gamma pulses was achieved by a discrimination method. The obtained results are displayed in the form of neutron and gamma spectra and attenuation relations which are used to derive the total macroscopic cross-sections for neutrons and total linear attenuation coefficients for gamma-rays. The values of neutron and gamma relaxation lengths are also derived for the investigated materials. 10 figs., 1 tabs.

  6. A method to describe inelastic gamma field distribution in neutron gamma density logging.

    Science.gov (United States)

    Zhang, Feng; Zhang, Quanying; Liu, Juntao; Wang, Xinguang; Wu, He; Jia, Wenbao; Ti, Yongzhou; Qiu, Fei; Zhang, Xiaoyang

    2017-11-01

    Pulsed neutron gamma density logging (NGD) is of great significance for radioprotection and density measurement in LWD, however, the current methods have difficulty in quantitative calculation and single factor analysis for the inelastic gamma field distribution. In order to clarify the NGD mechanism, a new method is developed to describe the inelastic gamma field distribution. Based on the fast-neutron scattering and gamma attenuation, the inelastic gamma field distribution is characterized by the inelastic scattering cross section, fast-neutron scattering free path, formation density and other parameters. And the contribution of formation parameters on the field distribution is quantitatively analyzed. The results shows the contribution of density attenuation is opposite to that of inelastic scattering cross section and fast-neutron scattering free path. And as the detector-spacing increases, the density attenuation gradually plays a dominant role in the gamma field distribution, which means large detector-spacing is more favorable for the density measurement. Besides, the relationship of density sensitivity and detector spacing was studied according to this gamma field distribution, therefore, the spacing of near and far gamma ray detector is determined. The research provides theoretical guidance for the tool parameter design and density determination of pulsed neutron gamma density logging technique. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Monte Carlo efficiency calibration of a neutron generator-based total-body irradiator

    International Nuclear Information System (INIS)

    Shypailo, R.J.; Ellis, K.J.

    2009-01-01

    Many body composition measurement systems are calibrated against a single-sized reference phantom. Prompt-gamma neutron activation (PGNA) provides the only direct measure of total body nitrogen (TBN), an index of the body's lean tissue mass. In PGNA systems, body size influences neutron flux attenuation, induced gamma signal distribution, and counting efficiency. Thus, calibration based on a single-sized phantom could result in inaccurate TBN values. We used Monte Carlo simulations (MCNP-5; Los Alamos National Laboratory) in order to map a system's response to the range of body weights (65-160 kg) and body fat distributions (25-60%) in obese humans. Calibration curves were constructed to derive body-size correction factors relative to a standard reference phantom, providing customized adjustments to account for differences in body habitus of obese adults. The use of MCNP-generated calibration curves should allow for a better estimate of the true changes in lean tissue mass that many occur during intervention programs focused only on weight loss. (author)

  8. Radioprotection of liver lipids of whole-body gamma-irradiated female rats by cystamine

    International Nuclear Information System (INIS)

    Ramanathan, R.; Misra, U.K.

    1976-01-01

    The effect of administration of cystamine (5 mg/100 g body weight) before 1,200 R whole-body gamma irradiation has been studied on irradiation-induced changes in liver and its subcellular fractions'lipids of fasted female rats. Cystamine prevented the irradiation-induced increase in liver triglycerides and liver mitochondrial total phospholipids, but it decreased microsomal total phospholipids and proteins. Cystamine prevented the radiation-induced increased 32 P-radioactivity (counts/min/μmole phospholipid phosphorus) of microsomal phosphatidyl choline. Cystamine prevented the radiation-induced increased uptake of NaH 2 32 PO 4 (counts/min/g liver) in liver microsomal phosphatidyl ethanolamine and supernatant phosphatidyl choline; but in microsomal phosphatidyl choline, cystamine did not do so, but on the other hand it itself increased the uptake in control rats. Cystamine did not prevent the irradiation-induced decreased incorporation of (U- 14 C)glucose into liver triglycerides, total phospholipids and phosphatidyl choline. Cystamine itself decreased the incorporation of (U- 14 C)glucose into liver triglycerides and phosphoglycerides of control rats. (orig.) [de

  9. Whole body detectors for clinical applications

    International Nuclear Information System (INIS)

    Silar, J.

    The requirements are presented on the parameters of whole-body detectors suitable for clinical retention assays and the detector-patient configuration described. A whole-body detector was developed with an axial configuration of two pairs of large-volume scintillation detectors with NaI(Tl) crystals. One pair is placed under the bed, the other above the bed on which the patient is being examined. The axes of the crystals are located at a distance of 90 cm apart. The field of vision of the detector is described for the application of a 137 Cs source in the air and in a 24 cm layer of water. The positive characteristics of the detector are listed as being homogeneous sensitivity, energy resolution, long-term stability of signal pulse amplitude and average pulse rate in the integral mode. The results obtained show that the detector may be used to evaluate the level of contamination of persons by gamma emitters within the region of approximately 800 Bq to 74 MBq. The error in converting the number of signal pulses in the integral mode does not exceed 50% for gamma emitters with a photon energy above 30O keV. (J.B.)

  10. 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)

  11. Neutron-gamma discrimination by pulse analysis with superheated drop detector

    International Nuclear Information System (INIS)

    Das, Mala; Seth, S.; Saha, S.; Bhattacharya, S.; Bhattacharjee, P.

    2010-01-01

    Superheated drop detector (SDD) consisting of drops of superheated liquid of halocarbon is irradiated to neutrons and gamma-rays from 252 Cf fission neutron source and 137 Cs gamma source, respectively, separately. Analysis of pulse height of signals at the neutron and gamma-ray sensitive temperature provides significant information on the identification of neutron and gamma-ray induced events.

  12. Stability evaluation and correction of a pulsed neutron generator prompt gamma activation analysis system

    Science.gov (United States)

    Source output stability is important for accurate measurement in prompt gamma neutron activation. This is especially true when measuring low-concentration elements such as in vivo nitrogen (~2.5% of body weight). We evaluated the stability of the compact DT neutron generator within an in vivo nitrog...

  13. Estimation of neutron energy distributions from prompt gamma emissions

    Science.gov (United States)

    Panikkath, Priyada; Udupi, Ashwini; Sarkar, P. K.

    2017-11-01

    A technique of estimating the incident neutron energy distribution from emitted prompt gamma intensities from a system exposed to neutrons is presented. The emitted prompt gamma intensities or the measured photo peaks in a gamma detector are related to the incident neutron energy distribution through a convolution of the response of the system generating the prompt gammas to mono-energetic neutrons. Presently, the system studied is a cylinder of high density polyethylene (HDPE) placed inside another cylinder of borated HDPE (BHDPE) having an outer Pb-cover and exposed to neutrons. The emitted five prompt gamma peaks from hydrogen, boron, carbon and lead can be utilized to unfold the incident neutron energy distribution as an under-determined deconvolution problem. Such an under-determined set of equations are solved using the genetic algorithm based Monte Carlo de-convolution code GAMCD. Feasibility of the proposed technique is demonstrated theoretically using the Monte Carlo calculated response matrix and intensities of emitted prompt gammas from the Pb-covered BHDPE-HDPE system in the case of several incident neutron spectra spanning different energy ranges.

  14. Plasma driven neutron/gamma generator

    Science.gov (United States)

    Leung, Ka-Ngo; Antolak, Arlyn

    2015-03-03

    An apparatus for the generation of neutron/gamma rays is described including a chamber which defines an ion source, said apparatus including an RF antenna positioned outside of or within the chamber. Positioned within the chamber is a target material. One or more sets of confining magnets are also provided to create a cross B magnetic field directly above the target. To generate neutrons/gamma rays, the appropriate source gas is first introduced into the chamber, the RF antenna energized and a plasma formed. A series of high voltage pulses are then applied to the target. A plasma sheath, which serves as an accelerating gap, is formed upon application of the high voltage pulse to the target. Depending upon the selected combination of source gas and target material, either neutrons or gamma rays are generated, which may be used for cargo inspection, and the like.

  15. A novel dual mode neutron-gamma imager

    International Nuclear Information System (INIS)

    Cooper, Robert Lee; Gerling, Mark; Brennan, James S.; Mascarenhas, Nicholas; Mrowka, Stanley; Marleau, Peter

    2010-01-01

    The Neutron Scatter Camera (NSC) can image fission sources and determine their energy spectra at distances of tens of meters and through significant thicknesses of intervening materials in relatively short times (1). We recently completed a 32 element scatter camera and will present recent advances made with this instrument. A novel capability for the scatter camera is dual mode imaging. In normal neutron imaging mode we identify and image neutron events using pulse shape discrimination (PSD) and time of flight in liquid scintillator. Similarly gamma rays are identified from Compton scatter in the front and rear planes for our segmented detector. Rather than reject these events, we show it is possible to construct a gamma-ray image by running the analysis in a 'Compton mode'. Instead of calculating the scattering angle by the kinematics of elastic scatters as is appropriate for neutron events, it can be found by the kinematics of Compton scatters. Our scatter camera has not been optimized as a Compton gamma-ray imager but is found to work reasonably. We studied imaging performance using a Cs137 source. We find that we are able to image the gamma source with reasonable fidelity. We are able to determine gamma energy after some reasonable assumptions. We will detail the various algorithms we have developed for gamma image reconstruction. We will outline areas for improvement, include additional results and compare neutron and gamma mode imaging.

  16. Physical principles of neutron-gamma materials monitoring

    Science.gov (United States)

    Pekarskii, G. Sh.

    1986-03-01

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

  17. Phosphorylation of histone H2AX as an indicator of received dose of gamma radiation after whole-body irradiation of rats

    Directory of Open Access Journals (Sweden)

    Radim Havelek

    2011-01-01

    Full Text Available The aim of our study was to determine whether phosphorylation of histone H2AX can be used as an indicator of received dose of gamma radiation after whole-body irradiation of rats. Wistar rats were irradiated by 1-10 Gy of gamma radiation by 60Co source. Value LD50/60 was 7.37 (4.68-8.05 Gy. Histone H2AX is phosphorylated by ATM kinase on serine 139 (γH2AX quickly after the irradiation. It forms microscopically visible foci in the site of double strand breaks of DNA. Flow-cytometric method was used for quantitative detection. This study is the first one that evaluated dose-dependency of H2AX phosphorylation in peripheral lymphocytes of rats irradiated by whole-body dose 1-10 Gy. Our data show a dose-dependent increase in γH2AX in rat peripheral blood lymphocytes 1 h after whole-body irradiation by the dose of 1-10 Gy. We proved that phosphorylation of histone H2AX is a prompt and reliable indicator of the received radiation dose suitable for rapid measurement before the number of lymphocytes in peripheral blood starts to decrease. It can be used already 1 h after the irradiation for an estimation of the received dose of radiation. Blood samples can be stored in 4 °C for 23 h without significantly affecting the result.

  18. Virtual Gamma Ray Radiation Sources through Neutron Radiative Capture

    Energy Technology Data Exchange (ETDEWEB)

    Scott Wilde, Raymond Keegan

    2008-07-01

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

  19. Materials testing by computerized tomography with neutrons and gamma-rays

    Energy Technology Data Exchange (ETDEWEB)

    El-Ghobary, A M; Bakkoush, F A; Megahid, R M [Reactor and Neutron Physics Department, Nuclear Research Center, A.E.A., Cairo (Egypt)

    1997-12-31

    The method of computerized tomography by fast neutrons and gamma-rays are used for inspecting and testing of materials by non-destructive technique. The transmission technique was applied using narrow collimated beams of reactor neutrons and gamma-ray. The neutron and gamma-rays transmitted through the object inspection were measured by means of a neutron gamma detector with Ne - 213 liquid organic scintillator. The undesired pulses of neutrons or gamma-rays are rejected from the transmitted beam by a discrimination technique based on the difference in the decay part of light pulse produced by recoil electrons or recoil protons. The transmitted neutrons or gamma-rays for different projections used to get the image of the section through the object investigated using the method of filtered back projection (FBP) algorithm. 8 figs.

  20. High-resolution gamma spectroscopy with whole-body and partial-body counters. Experience, recommendations. Report; Hochaufloesende Gamma-Spektrometrie an Ganz- und Teilkoerperzaehlern. Erfahrungen, Empfehlungen. Bericht

    Energy Technology Data Exchange (ETDEWEB)

    Sahre, P. [comp.

    1997-12-01

    The application of high-resolution gamma spectroscopy with whole-body and partial-body counters shows a steadily rising upward trend over the last few years. This induced the ``Arbeitskreis Inkorporationsueberwachung`` of the association ``Fachverband fuer Strahlenschutz e.V.`` to organise a meeting for joint elaboration of a guide on recommended applications of this measuring technique, based on a review of existing experience and results. A key item on the agenda of the meeting was the comparative evaluation of the Ge semiconductor detector and the NaI solid scintillation detector. (orig./CB) [Deutsch] Der Einsatz der hochaufloesenden Gammaspektroskopie in Ganz- und Teilkoerperzaehlern hat in den letzten Jahren stetig zugenommen. Der ``Arbeitskreis Inkorporationsueberwachung`` des Fachverbandes fuer Strahlenschutz e.V. hat darum bisherige Erfahrungen zusammengetragen und Empfehlungen fuer den Einsatz dieser Messtechnik erarbeitet. Der Schwerpunkt der Tagung lag beim Vergleich von Germaniumhalbleiter- mit Natriumjodid-Festszintillationsdetektoren.Tl-Detektoren eignen sich v.a. beim Vorhandensein bekannter und zeitlich konstanter Nuklidvektoren (Kernkraftwerke, Nuklearmedizin). Bei unbekanntem bzw. variablem Nuklidvektor (Stoerfall, Unfall, Forschung) sollen Ge-Detektoren benutzt werden (orig./ABI)

  1. Effect of Pseudomonas contamination or antibiotic decontamination of the GI tract on acute radiation lethality after neutron or gamma irradiation

    International Nuclear Information System (INIS)

    Geraci, J.P.; Jackson, K.L.; Mariano, M.S.

    1985-01-01

    The influence of antibiotic decontamination of Pseudomonas contamination of the GI tract prior to whole-body neutron or gamma irradiation was studied. It was observed that for fission neutron doses greater than 5.5 Gy, cyclotron-produced neutron doses greater than 6.7 Gy, and 137Cs gamma-ray doses greater than 14.4 Gy, the median survival time of untreated rats was relatively constant at 4.2 to 4.5 days, indicating death was due to intestinal injury. Within the dose range of 3.5 to 5.5 Gy of fission neutrons, 4.9 to 6.7 Gy of cyclotron-produced neutrons, and 9.6 to 14.4 Gy of gamma rays, median survival time of these animals was inversely related to dose and varied from 12 to 4.6 days. This change in survival time with dose reflects a transition in the mechanisms of acute radiation death from pure hematopoietic, to a combination of intestinal and hematopoietic, to pure intestinal death. Decontamination of the GI tract with antibiotics prior to irradiation increased median survival time 1 to 5 days in this transitional dose range. Contamination of the intestinal flora with Pseudomonas aeruginosa prior to irradiation reduced median survival time 1 to 5 days in the same radiation dose range. Pseudomonas-contaminated animals irradiated within this transitional dose range had maximum concentrations of total bacteria and Pseudomonas in their livers at the time of death. However, liver bacteria concentration was usually higher in gamma-irradiated animals, due to a smaller contribution of hematopoietic injury in neutron-irradiated animals. The effects of both decontamination of the GI tract and Pseudomonas contamination of the GI tract were negligible in the range of doses in which median survival time was dose independent, i.e., in the pure intestinal death dose range

  2. Studies on the effects of whole-body gamma irradiation on chickens infected with Eimeria tenella

    International Nuclear Information System (INIS)

    Merritt, S.V.

    1974-01-01

    Whole-body exposure of one- and three-week-old White Leghorn cockerels to 600 R gamma radiation (Cesium-137) 24 hours before oral inoculation with 500, 2500, 5000, or 50,000 Eimeria tenella oocysts produced a pattern of mortality differing markedly from nonirradiated, infected (NRI) control birds. When oocyst dosage was held constant (2500) and radiation exposure increased (250, 450, 600, 800, or 1000 R) a gradual increase in mortality rate with higher radiation dosages was observed among both one- and three-week-old birds. Birds irradiated 24 hours or more before inoculation were less able to survive infection than were those irradiated one hour before and one, two, three, or four days after inoculation. (U.S.)

  3. Analytical applications of neutron capture gamma-rays

    International Nuclear Information System (INIS)

    Lindstrom, R.M.; Paul, R.L.; Anderson, D.L.; Paul, R.L.

    1997-01-01

    Field and industrial applications of neutron capture gamma-ray spectrometry with isotopic sources or neutron generators are economically important. Geochemical exploration in boreholes is done routinely with neutron probes. Coal and ores are assayed with analyzers adjacent to a conveyor belt in dozens of industrial facilities. The use of capture gamma rays for explosives detection has been described in the literature, both for scanning airline baggage and for characterizing obsolete munitions; a packaged system for the latter is available commercially. Generalizations are drawn from the history of the field, and predictions are made about the future usefulness of capture gamma rays. (author)

  4. 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

  5. Earth formation pulsed neutron porosity logging system utilizing epithermal neutron and inelastic scattering gamma ray detectors

    International Nuclear Information System (INIS)

    Smith, H.D. Jr.; Smith, M.P.; Schultz, W.E.

    1978-01-01

    An improved pulsed neutron porosity logging system is provided in the present invention. A logging tool provided with a 14 MeV pulsed neutron source, an epithermal neutron detector and an inelastic scattering gamma ray detector is moved through a borehole. The detection of inelastic gamma rays provides a measure of the fast neutron population in the vicinity of the detector. repetitive bursts of neutrons irradiate the earth formation and, during the busts, inelastic gamma rays representative of the fast neutron population is sampled. During the interval between bursts the epithermal neutron population is sampled along with background gamma radiation due to lingering thermal neutrons. the fast and epithermal neutron population measurements are combined to provide a measurement of formation porosity

  6. Effect of antibiotic decontamination of the GI tract on survival time after neutron and gamma irradiation

    International Nuclear Information System (INIS)

    Geraci, J.P.; Jackson, K.L.; Mariano, M.S.

    1984-01-01

    Antibiotic decontaminated and conventional rats were whole-body irradiated with 8 MeV neutrons (1.5 to 13 Gy) or 137 Cs gamma radiation (9 to 20 Gy). The animals were checked for survival at four hour intervals from the second to the seventh day postirradiation and at eight hour intervals on other days. Decontamination of the GI tract increased median survival time 1 to 5 days in this range of dose dependency, whereas the effect of decontamination was negligible for doses that produced mostly intestinal death. These results suggest that sepsis and endotoxin produced by bacteria from the intestinal tract play little role in acute intestinal radiation death

  7. The LDsub(50/30) and the survival time in whole-body gamma-irradiated conventional and germfree Minnesota miniature piglets

    International Nuclear Information System (INIS)

    Mandel, L.; Travnicek, J.; Talafantova, M.; Zahradnickova, M.

    1980-01-01

    The median lethal exposure causing the death in 30 days after single whole-body gamma-irradiation (the LD 50/30) was found to be 2731 MBq (73.8 mC/kg) for conventional piglets, but 3226 MBq (87.2 mC/kg) for germ-free piglets both irradiated 14 days after birth. After lethal exposures, the survival time in germ-free piglets was prolonged for 7 days in comparison with conventional piglets. (author)

  8. DNA-repair after irradiation of cells with gamma-rays and neutrons

    International Nuclear Information System (INIS)

    Altmann, H.

    1975-11-01

    The structural alterations of calf thymus DNA produced by neutron or gamma irradiation were observed by absorption spectra, sedimentation rate and viscosity measurements. Mixed neutron-gamma irradiation produced fewer single and double strand breaks compared with pure gamma irradiation. RBE-values for mixed neutron-gamma radiation were less than 1, and DNA damage decreased with increasing neutron dose rate. Repair processes of DNA occuring after irradiation were measured in mouse spleen suspensions and human lymphocytes using autoradiographic methods and gradient centrifugations. The number of labelled cells was smaller after mixed neutron-gamma irradiation than after gamma irradiation. The rejoining of strand breaks in alkaline and neutral sucrose was more efficient after gamma irradiation than after mixed neutron-gamma irradiation. Finally, the effect of detergents Tween 80 and Nonident P40 on unscheduled DNA synthesis was studied by autoradiography after mixed neutron-gamma irradiation (Dn=5 krad). The results showed that the DNA synthesis was inhibited by detergent solutions of 0.002%

  9. Neutron and gamma-ray toxicity studies

    International Nuclear Information System (INIS)

    Ainsworth, E.J.

    1975-01-01

    The focus of the program is on late effects of neutron and gamma radiation and assessment of risk. Principal research activities are in two complementary areas: life-span experiments with large populations of laboratory mice to compare the effectiveness of single or protracted doses of neutron or gamma radiation for life shortening due to cancer and other debilitating noncancerous diseases; and basic research on cellular injury and recovery for the evaluation of potential contributions of latent injury in the mouse circulatory, immune, and hematopoietic systems to life shortening, and for the comparison of late radiation effects in proliferating tissues. The data are used to test existing models and to formulate new models for prediction of radiation hazards and the relative biological effectiveness (RBE) of fission neutrons, particularly at low radiation doses. The neutron dose-response curve is nonlinear, with the life shortening effect decreasing from 3-4 day/rad to 1 day/rad with increasing dose over the range of 20-240 rad. Clearly, linear extrapolations from high neutron doses to estimate life shortening at low doses would underestimate risk; the underestimation is even greater when the enhancement of life shortening produced by fractionated neutron exposure, described previously by us, is also considered. These results from single neutron doses deviate from predictions of total dose dependency based on the predictive model of Kellerer and Rossi. The shape of the gamma radiation dose-response curve is linear over the range of 90 to 788 rad; linear dose-response curves for gamma radiation have been described previously by others, but a quadratic function has been considered by some to be most applicable

  10. Elpasolite Planetary Ice and Composition Spectrometer (EPICS): A Low-Resource Combined Gamma-Ray and Neutron Spectrometer for Planetary Science

    Science.gov (United States)

    Stonehill, L. C.; Coupland, D. D. S.; Dallmann, N. A.; Feldman, W. C.; Mesick, K.; Nowicki, S.; Storms, S.

    2017-12-01

    The Elpasolite Planetary Ice and Composition Spectrometer (EPICS) is an innovative, low-resource gamma-ray and neutron spectrometer for planetary science missions, enabled by new scintillator and photodetector technologies. Neutrons and gamma rays are produced by cosmic ray interactions with planetary bodies and their subsequent interactions with the near-surface materials produce distinctive energy spectra. Measuring these spectra reveals details of the planetary near-surface composition that are not accessible through any other phenomenology. EPICS will be the first planetary science instrument to fully integrate the neutron and gamma-ray spectrometers. This integration is enabled by the elpasolite family of scintillators that offer gamma-ray spectroscopy energy resolutions as good as 3% FWHM at 662 keV, thermal neutron sensitivity, and the ability to distinguish gamma-ray and neutron signals via pulse shape differences. This new detection technology will significantly reduce size, weight, and power (SWaP) while providing similar neutron performance and improved gamma energy resolution compared to previous scintillator instruments, and the ability to monitor the cosmic-ray source term. EPICS will detect scintillation light with silicon photomultipliers rather than traditional photomultiplier tubes, offering dramatic additional SWaP reduction. EPICS is under development with Los Alamos National Laboratory internal research and development funding. Here we report on the EPICS design, provide an update on the current status of the EPICS development, and discuss the expected sensitivity and performance of EPICS in several potential missions to airless bodies.

  11. The recovery of bone marrow derived GM-CFU in baboons unilaterally exposed to a total body LD50/30d mixed neutron-gamma irradiation

    International Nuclear Information System (INIS)

    Herodin, F.; Orfeuvre, H.; Janodet, D.; Mestries, J.C.; Fatome, M.

    1990-01-01

    The unilateral exposure of baboons to a total body LD 50/30d mixed neutron/gamma irradiation was characterized to be non uniform in dose distribution. The pattern of recovery of granulocyte-macrophage progenitors in bone marrow samples collected from entrance and exit sides respectively is consistent with this observed heterogeneity [fr

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

    Energy Technology Data Exchange (ETDEWEB)

    Ryzhikov, V.; Grinyov, B.; Piven, L.; Onyshchenko, G.; Sidletskiy, O. [Institute for Scintillation Materials of the NAS of Ukraine, Kharkov, (Ukraine); Naydenov, S. [Institute for Single Crystals of the National Academy of Sciences of Ukraine, Kharkov, (Ukraine); Pochet, T. [DETEC-Europe, Vannes (France); Smith, C. [Naval Postgraduate School, Monterey, CA (United States)

    2015-07-01

    It is known that solid-state scintillators can be used for detection of both gamma radiation and neutron flux. In the past, neutron detection efficiencies of such solid-state scintillators did not exceed 5-7%. At the same time it is known that the detection efficiency of the gamma-neutron radiation characteristic of nuclear fissionable materials is by an order of magnitude higher than the efficiency of detection of neutron fluxes alone. Thus, an important objective is the creation of detection systems that are both highly efficient in gamma-neutron detection and also capable of exhibiting high gamma suppression for use in the role of detection of neutron radiation. In this work, we present the results of our experimental and theoretical studies on the detection efficiency of fast neutrons from a {sup 239}Pu-Be source by the heavy oxide scintillators BGO, GSO, CWO and ZWO, as well as ZnSe(Te, O). The most probable mechanism of fast neutron interaction with nuclei of heavy oxide scintillators is the inelastic scattering (n, n'γ) reaction. In our work, fast neutron detection efficiencies were determined by the method of internal counting of gamma-quanta that emerge in the scintillator from (n, n''γ) reactions on scintillator nuclei with the resulting gamma energies of ∼20-300 keV. The measured efficiency of neutron detection for the scintillation crystals we considered was ∼40-50 %. The present work included a detailed analysis of detection efficiency as a function of detector and area of the working surface, as well as a search for new ways to create larger-sized detectors of lower cost. As a result of our studies, we have found an unusual dependence of fast neutron detection efficiency upon thickness of the oxide scintillators. An explanation for this anomaly may involve the competition of two factors that accompany inelastic scattering on the heavy atomic nuclei. The transformation of the energy spectrum of neutrons involved in the (n, n

  13. Neutron Capture Gamma-Ray Libraries for Nuclear Applications

    International Nuclear Information System (INIS)

    Sleaford, B. W.; Summers, N.; Escher, J.; Firestone, R. B.; Basunia, S.; Hurst, A.; Krticka, M.; Molnar, G.; Belgya, T.; Revay, Z.; Choi, H. D.

    2011-01-01

    The neutron capture reaction is useful in identifying and analyzing the gamma-ray spectrum from an unknown assembly as it gives unambiguous information on its composition. This can be done passively or actively where an external neutron source is used to probe an unknown assembly. There are known capture gamma-ray data gaps in the ENDF libraries used by transport codes for various nuclear applications. The Evaluated Gamma-ray Activation file (EGAF) is a new thermal neutron capture database of discrete line spectra and cross sections for over 260 isotopes that was developed as part of an IAEA Coordinated Research Project. EGAF is being used to improve the capture gamma production in ENDF libraries. For medium to heavy nuclei the quasi continuum contribution to the gamma cascades is not experimentally resolved. The continuum contains up to 90% of all the decay energy and is modeled here with the statistical nuclear structure code DICEBOX. This code also provides a consistency check of the level scheme nuclear structure evaluation. The calculated continuum is of sufficient accuracy to include in the ENDF libraries. This analysis also determines new total thermal capture cross sections and provides an improved RIPL database. For higher energy neutron capture there is less experimental data available making benchmarking of the modeling codes more difficult. We are investigating the capture spectra from higher energy neutrons experimentally using surrogate reactions and modeling this with Hauser-Feshbach codes. This can then be used to benchmark CASINO, a version of DICEBOX modified for neutron capture at higher energy. This can be used to simulate spectra from neutron capture at incident neutron energies up to 20 MeV to improve the gamma-ray spectrum in neutron data libraries used for transport modeling of unknown assemblies.

  14. Neutron Capture Gamma-Ray Libraries for Nuclear Applications

    International Nuclear Information System (INIS)

    Sleaford, B.W.; Firestone, R.B.; Summers, N.; Escher, J.; Hurst, A.; Krticka, M.; Basunia, S.; Molnar, G.; Belgya, T.; Revay, Z.; Choi, H.D.

    2010-01-01

    The neutron capture reaction is useful in identifying and analyzing the gamma-ray spectrum from an unknown assembly as it gives unambiguous information on its composition. this can be done passively or actively where an external neutron source is used to probe an unknown assembly. There are known capture gamma-ray data gaps in the ENDF libraries used by transport codes for various nuclear applications. The Evaluated Gamma-ray Activation file (EGAF) is a new thermal neutron capture database of discrete line spectra and cross sections for over 260 isotopes that was developed as part of an IAEA Coordinated Research project. EGAF is being used to improve the capture gamma production in ENDF libraries. For medium to heavy nuclei the quasi continuum contribution to the gamma cascades is not experimentally resolved. The continuum contains up to 90% of all the decay energy and is modeled here with the statistical nuclear structure code DICEBOX. This code also provides a consistency check of the level scheme nuclear structure evaluation. The calculated continuum is of sufficient accuracy to include in the ENDF libraries. This analysis also determines new total thermal capture cross sections and provides an improved RIPL database. For higher energy neutron capture there is less experimental data available making benchmarking of the modeling codes more difficult. They are investigating the capture spectra from higher energy neutrons experimentally using surrogate reactions and modeling this with Hauser-Feshbach codes. This can then be used to benchmark CASINO, a version of DICEBOX modified for neutron capture at higher energy. This can be used to simulate spectra from neutron capture at incident neutron energies up to 20 MeV to improve the gamma-ray spectrum in neutron data libraries used for transport modeling of unknown assemblies.

  15. Neutron and gamma irradiation damage to organic materials.

    Energy Technology Data Exchange (ETDEWEB)

    White, Gregory Von, II; Bernstein, Robert

    2012-04-01

    This document discusses open literature reports which investigate the damage effects of neutron and gamma irradiation on polymers and/or epoxies - damage refers to reduced physical chemical, and electrical properties. Based on the literature, correlations are made for an SNL developed epoxy (Epon 828-1031/DDS) with an expected total fast-neutron fluence of {approx}10{sup 12} n/cm{sup 2} and a {gamma} dosage of {approx}500 Gy received over {approx}30 years at < 200 C. In short, there are no gamma and neutron irradiation concerns for Epon 828-1031/DDS. To enhance the fidelity of our hypotheses, in regards to radiation damage, we propose future work consisting of simultaneous thermal/irradiation (neutron and gamma) experiments that will help elucidate any damage concerns at these specified environmental conditions.

  16. Simultaneous use of 82Br and 24Na radionuclides in the whole-body counting of animals by high-resolution gamma-ray spektrometry

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav; Babický, Arnošt; Vobecký, Miloslav

    2008-01-01

    Roč. 278, č. 3 (2008), s. 571-574 ISSN 0236-5731 Grant - others:EC(XE) LSHG-CT-2004-511978 Institutional research plan: CEZ:AV0Z50110509; CEZ:AV0Z40310501 Keywords : gamma-spectrometry * whole-body counting * radionuclide Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.659, year: 2008

  17. Application of the decoupling scheme on complex neutron-gamma shielding problems

    Energy Technology Data Exchange (ETDEWEB)

    Feher, S. [Institute of Nuclear Technology, Technical University of Budapest, Budapest (Hungary); Leege, P.F.A. de; Hoogenboom, J.E.; Kloosterman, J.L. [Interfaculty Reactor Institute, Delft University of Technology, Delft (Netherlands)

    2000-03-01

    Coupled neutron-gamma shielding calculations using S{sub n} transport theory can be time consuming, especially for two- and three-dimensional geometries. In general, the CPU time of these calculations increases stronger than linear with increasing number of neutron and gamma energy groups, and depends on the order of Legendre expansion and number of S{sub n} directions used. This fact induced the idea of the decoupling method, which seems applicable to accelerate coupled neutron-gamma shielding calculations. The data included in a combined neutron-gamma library can be readily separated into a library containing neutron data only and another library containing gamma data only. Separate calculations for neutrons and gammas are performed on complex geometries using a different Legendre order expansion for neutrons and gammas. CPU savings of 60 to 85% can be achieved for the two-dimensional DORT and three-dimensional TORT calculations respectively. (author)

  18. Research on internal dosimetry for some of gamma emitting nuclides for radiation workers by direct method (in-vivo) with using a chair-type whole-body counter

    International Nuclear Information System (INIS)

    Nguyen Van Hung; Pham Hung Thai

    2003-01-01

    This research objective is to establish a chair-type whole-body counter with using NaI(Ti) detector in large sizes and whole-body standard phantoms as well as to apply the computational program of LUDEP 2.0. Steel holder with a lead collimator, two whole-body standard phantoms in Vietnamese adults (one for male and another for female) by plastic material, electronic blocks of ADC and MCD (8K), MCA program for measuring gamma spectrum by VB6 language in Windows are established and made. In addition, applied research for the program of LUDEP 2.0 in order to calculate and evaluated internal doses for radiation workers is carried out. (author)

  19. Use of a pulsed neutron generator for in vivo measurement of body carbon

    International Nuclear Information System (INIS)

    Kehayias, J.J.; Ellis, K.J.; Cohn, S.H.; Yasumura, S.

    1986-01-01

    The measurement of total body fat is of importance in studies of nutritional assessment, dietary regimens, and for the management of obesity. In the past, fat has been determined either by anthropometric methods, which introduce high uncertainties, or by model-dependent estimation of fat-free tissue. The validity, however, of the different models in disease is questionable. Total body carbon measurements provide a more direct evaluation of body fat both in normal subjects and in patients. The authors present here a facility for carbon measurements without the use of a major accelerator. The same facility can be used for the measurement of other major body elements and for the evaluation of the body's compartments. Carbon is measured in vivo through neutron inelastic scattering, by detecting the 4.44 MeV gamma rays. A miniature (10 cm long) 14 MeV D-T neutron generator is used. The short half-life of the 4.44 MeV state of carbon requires detection of the gamma rays simultaneously with the 10 μs neutron pulse. Generators with low pulsing rate were found inappropriate for carbon measurement because of their low duty-cycle (high neutron output during pulse). The detection system consists of NaI(T1) detectors and fast electronics for handling the high even rate during the neutron pulse. A description of the facility and an evaluation of the technique will be presented

  20. Neutron counting and gamma spectroscopy with PVT detectors

    International Nuclear Information System (INIS)

    Mitchell, Dean James; Brusseau, Charles A.

    2011-01-01

    Radiation portals normally incorporate a dedicated neutron counter and a gamma-ray detector with at least some spectroscopic capability. This paper describes the design and presents characterization data for a detection system called PVT-NG, which uses large polyvinyl toluene (PVT) detectors to monitor both types of radiation. The detector material is surrounded by polyvinyl chloride (PVC), which emits high-energy gamma rays following neutron capture reactions. Assessments based on high-energy gamma rays are well suited for the detection of neutron sources, particularly in border security applications, because few isotopes in the normal stream of commerce have significant gamma ray yields above 3 MeV. Therefore, an increased count rate for high-energy gamma rays is a strong indicator for the presence of a neutron source. The sensitivity of the PVT-NG sensor to bare 252 Cf is 1.9 counts per second per nanogram (cps/ng) and the sensitivity for 252 Cf surrounded by 2.5 cm of polyethylene is 2.3 cps/ng. The PVT-NG sensor is a proof-of-principal sensor that was not fully optimized. The neutron detector sensitivity could be improved, for instance, by using additional moderator. The PVT-NG detectors and associated electronics are designed to provide improved resolution, gain stability, and performance at high-count rates relative to PVT detectors in typical radiation portals. As well as addressing the needs for neutron detection, these characteristics are also desirable for analysis of the gamma-ray spectra. Accurate isotope identification results were obtained despite the common impression that the absence of photopeaks makes data collected by PVT detectors unsuitable for spectroscopic analysis. The PVT detectors in the PVT-NG unit are used for both gamma-ray and neutron detection, so the sensitive volume exceeds the volume of the detection elements in portals that use dedicated components to detect each type of radiation.

  1. Self-powered neutron and gamma-ray flux detector

    International Nuclear Information System (INIS)

    Allan, C.J.; Shields, R.B.; Lynch, G.F.; Cuttler, J.M.

    1980-01-01

    A new type of self-powered neutron detector was developed which is sensitive to both the neutron and gamma-ray fluxes. The emitter comprises two parts. The central emitter core is made of materials that generate high-energy electrons on exposure to neutrons. The outer layer acts as a gamma-ray/electron converter, and since it has a higher atomic number and higher back-scattering coefficient than the collector, increases the net outflow or emmission of electrons. The collector, which is around the emitter outer layer, is insulated from the outer layer electrically with dielectric insulation formed from compressed metal-oxide powder. The fraction of electrons given off by the emitter that is reflected back by the collector is less than the fraction of electrons emitted by the collector that is reflected back by the emitter. The thickness of the outer layer needed to achieve this result is very small. A detector of this design responds to external reactor gamma-rays as well as to neutron capture gamma-rays from the collector. The emitter core is either nickel, iron or titanium, or alloys based on these metals. The outer layer is made of platinum, tantalum, osmium, molybdenum or cerium. The detector is particularly useful for monitoring neutron and gamma ray flux intensities in nuclear reactor cores in which the neutron and gamma ray flux intensities are closely proportional, are unltimately related to the fission rate, and are used as measurements of nuclear reactor power. (DN)

  2. Random pulsing of neutron source for inelastic neutron scattering gamma ray spectroscopy

    International Nuclear Information System (INIS)

    Hertzog, R.C.

    1981-01-01

    Method and apparatus are described for use in the detection of inelastic neutron scattering gamma ray spectroscopy. Data acquisition efficiency is enhanced by operating a neutron generator such that a resulting output burst of fast neutrons is maintained for as long as practicably possible until a gamma ray is detected. Upon the detection of a gamma ray the generator burst output is terminated. Pulsing of the generator may be accomplished either by controlling the burst period relative to the burst interval to achieve a constant duty cycle for the operation of the generator or by maintaining the burst period constant and controlling the burst interval such that the resulting mean burst interval corresponds to a burst time interval which reduces contributions to the detected radiation of radiation occasioned by other than the fast neutrons

  3. The measurement of gamma ray induced heating in a mixed neutron and gamma ray environment

    International Nuclear Information System (INIS)

    Chiu, H.K.

    1991-10-01

    The problem of measuring the gamma heating in a mixed DT neutron and gamma ray environment was explored. A new detector technique was developed to make this measurement. Gamma heating measurements were made in a low-Z assembly irradiated with 14-Mev neutrons and (n, n') gammas produced by a Texas Nuclear Model 9400 neutron generator. Heating measurements were made in the mid-line of the lattice using a proportional counter operating in the Continuously-varied Bias-voltage Acquisition mode. The neutron-induced signal was separated from the gamma-induced signal by exploiting the signal rise-time differences inherent to radiations of different linear energy transfer coefficient, which are observable in a proportional counter. The operating limits of this measurement technique were explored by varying the counter position in the low-Z lattice, hence changing the irradiation spectrum observed. The experiment was modelled numerically to help interpret the measured results. The transport of neutrons and gamma rays in the assembly was modelled using the one- dimensional radiation transport code ANISN/PC. The cross-section set used for these calculations was derived from the ENDF/B-V library using the code MC 2 -2 for the case of DT neutrons slowing down in a low-Z material. The calculated neutron and gamma spectra in the slab and the relevant mass-stopping powers were used to construct weighting factors which relate the energy deposition in the counter fill-gas to that in the counter wall and in the surrounding material. The gamma energy deposition at various positions in the lattice is estimated by applying these weighting factors to the measured gamma energy deposition in the counter at those locations

  4. Formulation of the relationship between indices of neutron-gamma and gamma-gamma method and the percentrage of iron

    International Nuclear Information System (INIS)

    Majorowicz, J.

    1973-01-01

    In this article, the author presents the possibility of a complex utilization of radiometric logging methods, neutron-gamma profiling and gamma-gamma density logging for determining percentage of iron and establishing geophysical possibilities of identifying zones of economically profitable ores in borehole profiles. Figures present the correlations between indices of neutron-gamma and gamma-gamma logging methods and the percentage of iron, as well as the correlation of neutron-gamma and gamma-gamma indices for zones minerallized with iron ores. The article presents the correlational analyses of the results: the correlational coefficients are given as well as total error in determining iron content on the basis of each of the methods described. Next, a multidimensional statistical analysis is carried out on the results obtained. On the basis of the two-dimensional correlational coefficients calculated and the average standard deviation, an equation of linear regression was formulated, simultaneously involving three parameters - the indices of neutron-gamma and gamma-gamma logging and the percentage of iron. The multiple correlational coefficient obtained markedly exceeds the two-dimentional correlation coefficient (r=0.974>rsub(xz)>rsub(yz)>rsub(xy)). The given method of utilizing multidimensional statistics in borehole geophysics for identifying iron ores is an efficient one. On the basis of several relationships among independent variables which are less obvious (smaller values of correlational coefficient), it is possible to obtain a single distinct relationship involving all variables simultaneously. (author)

  5. Bulk moisture determination in building materials by fast neutron/gamma technique

    International Nuclear Information System (INIS)

    Padron Diaz, I.; Felipe Desdin, L.; Martin Hernandez, G.; Shtejer, K.; Perez Tamayo, N.; Ceballos, C.; Lemus, O.

    1998-01-01

    Fast Neutron/Gamma Transmission technique has been improved to allow to measure moisture content in building materials. In order to improve fast neutron/gamma discrimination in the transmission system employing the NE-213 scintillation detector a pulse shape discrimination system was constructed at the CEADEN. A separate neutron/gamma detection approach was used with neutron transmission measurement using an Am-Be neutron source and a BF 3 detector and gamma transmission measurement using a collimated 137 Cs source and a NaI scintillator

  6. Development of the neutron filters for JET gamma-ray cameras

    International Nuclear Information System (INIS)

    Soare, S.; Curuia, M.; Anghel, M.; Constantin, M.; David, E.; Kiptily, V.; Prior, P.; Edlington, T.; Griph, S.; Krivchenkov, Y.; Popovichev, S.; Riccardo, V.; Syme, B; Thompson, V.; Murari, A.; Zoita, V.; Bonheure, G.; Le Guern

    2007-01-01

    The JET gamma-ray camera diagnostics have already provided valuable information on the gamma-ray imaging of fast ion evaluation in JET plasmas. The JET Gamma-Ray Cameras (GRC) upgrade project deals with the design of appropriate neutron/gamma-ray filters ('neutron attenuaters').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). 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. FEA methods used to evaluate the behaviour of the filter casings under the loadings (internal hydrostatic pressure, torques) have proven the stability of the structure. (authors)

  7. Prompt gamma neutron activation analysis

    International Nuclear Information System (INIS)

    Goswami, A.

    2003-01-01

    Prompt gamma neutron activation analysis (PGNAA) is a technique for the analysis of elements present in solid, liquid and gaseous samples by measuring the capture gamma rays emitted from the sample during neutron irradiation. The technique is complementary to conventional neutron activation analysis (NAA) as it can be used in number of cases where NAA fails. Though the technique was first used in sixties, the advantage of the technique was first highlighted by Lindstrom and Anderson. PGNAA is increasingly being used as a rapid, instrumental, nondestructive and multielement analysis technique. A monograph and several excellent reviews on this topic have appeared recently. In this review, an attempt has been made to bring out the essential aspects of the technique, experimental arrangement and instrumentation involved, and areas of application. Some of the results will also be presented

  8. The A.E.E. Winfrith Whole Body Monitor

    International Nuclear Information System (INIS)

    Peabody, C.O.; Fraser, V.M.; Speight, R.G.

    1962-10-01

    The function, design and construction of the A.E.E. Winfrith Whole Body Monitor are described. The main purpose of the monitor is to measure gamma emitting radioisotopes in the human body. Its performance, capabilities and limitations are discussed and a summary is given of experience gained and results obtained during the first few months of operation. The future programme of measurements and development is outlined. Some basic design criteria are put forward as a result of the experience and results obtained. (author)

  9. Early changes of cortical blood flow, brain temperature and electrical activity after whole-body irradiation of the monkey (Macaca fascicularis) (dose range: 3-20 Gy)

    International Nuclear Information System (INIS)

    Court, L.; Gourmelon, P.; Mestries, J.C.

    1987-02-01

    A polyparametric investigation was carried out on 31 monkeys chronically wearing bioinstrumentation allowing to get and process simultaneously local brain blood flow, cerebral temperature, and energies in various frequency bands of the brain electrical activity. This method, which supplied data during several consecutive days, made it possible to study both the biological rhythms at the level of the various parameters, and their fast variations. The effects of whole-body gamma or neutron-gamma irradiation were studied in the 3-20 Gy dose range. Immediate changes after exposure demonstrated different radiosensitivities at the level of the rhythms of the various parameters, and/or their recovery, as well as dose-effect relationships [fr

  10. Deduction of solar neutron fluences from large gamma-ray flares

    International Nuclear Information System (INIS)

    Yoshimori, Masato; Watanabe, Hiroyuki; Takahashi, Kazuyoshi.

    1986-01-01

    Solar neutron fluences from large gamma-ray flares are deduced from accelerated proton spectra and numbers derived from the gamma-ray observations. The deduced solar neutron fluences range from 1 to 200 neutrons cm -2 . The present result indicates a possibility that high sensitivity ground-based neutron monitors can detect solar neutron events, just as detected by the Jungfraujoch and Rome neutron monitors. (author)

  11. Scanning of Cargo Containers by Gamma-Ray and Fast Neutron Radiography

    International Nuclear Information System (INIS)

    Yousri, A.M.; Bashter, I.I.; Megahid, M.R.; Osman, A.M.; Kansouh, W.A.; Reda, A.M.

    2011-01-01

    This paper describes the combined systems which were installed and tested to detect contraband smuggled in cargo containers. These combined systems are based on radiographers work by gamma-rays emitted from point source 60 Co with 0.5 Ci activity and neutrons emitted from point isotopic sources of Pu-α-Be as well as 14 MeV neutrons emitted from sealed tube neutron generator. The transmitted gamma ray through the inspected object was measured by gamma detection system with NaI(Tl) detector while the transmitted fast neutron beam was measured by a neutron gamma detection system with stilbene organic scintillator. The later possess the capability of discrimination between between gamma and neutron pulses using a discrimination system based on pulse shape discrimination method. The measured intensities of primary incident and transmitted beams of gamma-rays and fast neutrons were used to construct 2D cross-sectional images of the inspected objects hidden directly within benign materials of the container and for object screened by high dense material to stop object detection by gamma or X-rays. The constructed images for the inspected objects show the good capability and effectiveness of the installed gamma and neutron radiographers to detect illicit materials hidden in air cargo containers and sea containers of med size. They have also indicated that the developed scanning systems possess the ease of mobility and low cost of scanning

  12. Development of a low-cost whole body counter

    International Nuclear Information System (INIS)

    Smith, M.H.; Gross, G.P.

    1991-01-01

    This paper documents the construction and calibration of a whole-body counter for the Radiation Safety Office of the Mayo Clinic in Rochester, MN. Changes in the federal regulations may require improved documentation of internal dose for radiation workers. A relatively inexpensive and simple chair-type whole-body counter may suit the needs of many organizations for in vivo assessment of gamma emitting radionuclides. A simple calibration phantom and a spreadsheet computer program were developed in conjunction with the counter. The spreadsheet can be used to calculate an estimate of committed effective dose equivalent based on activity in a subject and data from ICRP Publication 30. Using a count time of 10 minutes, the counter's minimum detectable activity ranged from 370 Bq to 1,110 Bq for 60 Co and 57 Co respectively. Other institutions will be able to assemble whole-body counters at low cost, often from surplus components. The spreadsheet is easily adapted to the needs of any institution and uses current methodology to estimate internal dose

  13. 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

  14. Effect of ionizing whole-body irradiation on the primary and secondary antibody reaction of cows to injection of human gamma globulin

    International Nuclear Information System (INIS)

    Koch, F.; Buchholz, I.; Mehlhorn, G.

    1989-01-01

    In 3 experiments 29 cows were exposed to whole-body irradiation, using 9 MeV X-rays of a linear accelerator, with doses of 1.50 and 2.00 Gy or 60 Co gamma rays with a dose of 2.75 Gy, as a midline dose. 2 weeks prior to irradiation the first immunization was applied using human gamma globulin. 4 or 5 weeks after irradiation a second immunization was carried out. The antibody titres were investigated. The irradiation failed to affect the antibody titres after the first immunization. After the second immunization the antibody titres of the irradiated animals remained diminished significantly (α = 0.05). This has been attributed to a damage of the memory cell pool. (author)

  15. On the accuracy of protein determination in large biological samples by prompt gamma neutron activation analysis

    International Nuclear Information System (INIS)

    Kasviki, K.; Stamatelatos, I.E.; Yannakopoulou, E.; Papadopoulou, P.; Kalef-Ezra, J.

    2007-01-01

    A prompt gamma neutron activation analysis (PGNAA) facility has been developed for the determination of nitrogen and thus total protein in large volume biological samples or the whole body of small animals. In the present work, the accuracy of nitrogen determination by PGNAA in phantoms of known composition as well as in four raw ground meat samples of about 1 kg mass was examined. Dumas combustion and Kjeldahl techniques were also used for the assessment of nitrogen concentration in the meat samples. No statistically significant differences were found between the concentrations assessed by the three techniques. The results of this work demonstrate the applicability of PGNAA for the assessment of total protein in biological samples of 0.25-1.5 kg mass, such as a meat sample or the body of small animal even in vivo with an equivalent radiation dose of about 40 mSv

  16. On the accuracy of protein determination in large biological samples by prompt gamma neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kasviki, K. [Institute of Nuclear Technology and Radiation Protection, NCSR ' Demokritos' , Aghia Paraskevi, Attikis 15310 (Greece); Medical Physics Laboratory, Medical School, University of Ioannina, Ioannina 45110 (Greece); Stamatelatos, I.E. [Institute of Nuclear Technology and Radiation Protection, NCSR ' Demokritos' , Aghia Paraskevi, Attikis 15310 (Greece)], E-mail: ion@ipta.demokritos.gr; Yannakopoulou, E. [Institute of Physical Chemistry, NCSR ' Demokritos' , Aghia Paraskevi, Attikis 15310 (Greece); Papadopoulou, P. [Institute of Technology of Agricultural Products, NAGREF, Lycovrissi, Attikis 14123 (Greece); Kalef-Ezra, J. [Medical Physics Laboratory, Medical School, University of Ioannina, Ioannina 45110 (Greece)

    2007-10-15

    A prompt gamma neutron activation analysis (PGNAA) facility has been developed for the determination of nitrogen and thus total protein in large volume biological samples or the whole body of small animals. In the present work, the accuracy of nitrogen determination by PGNAA in phantoms of known composition as well as in four raw ground meat samples of about 1 kg mass was examined. Dumas combustion and Kjeldahl techniques were also used for the assessment of nitrogen concentration in the meat samples. No statistically significant differences were found between the concentrations assessed by the three techniques. The results of this work demonstrate the applicability of PGNAA for the assessment of total protein in biological samples of 0.25-1.5 kg mass, such as a meat sample or the body of small animal even in vivo with an equivalent radiation dose of about 40 mSv.

  17. Measurements of whole-body radioactivity in the UK population

    International Nuclear Information System (INIS)

    Fenwick, J.D.; Boddy, K.; McKenzie, A.L.; Oxby, C.B.

    1992-01-01

    A national survey of whole-body radioactivity was undertaken. A mobile whole-body counter visited collaborating Medical Physics Departments and Hospitals in England and Wales. Data were also obtained from an installed whole-body counter at the West Cumberland Hospital, Whitehaven, and from a control site at Addenbrooke's Hospital, Cambridge. 1657 volunteer members of the public were measured, including 162 children. 36% of volunteers had been measured in a similar survey 2 years earlier, and showed between a two and five fold reduction in body radiocaesium. No radiocaesium was detected in 54% of people measured. Measurements showed a progressive fall over the course of the study, reaching a baseline of 0.3 Bq 137 Cs/gK. In 1989, the additional radiation dose incurred from radiocaesium varied from a maximum of 4.1 μSv in Cumbria to 1.5 μSv in the South East, compared with the average annual radiation dose of 2500 μSv due to all other causes. No other gamma-emitting radionuclides were found. Results are consistent with Chernobyl as the source of the radiocaesium detected. (author)

  18. Protective Effects of Ibuprofen and L-Carnitine Against Whole Body Gamma Irradiation-Induced Duodenal Mucosal Injury

    Directory of Open Access Journals (Sweden)

    Meryem Akpolat

    2011-03-01

    Full Text Available Objective: Ibuprofen and L-carnitine have been demonstrated to provide radioprotective activity to the hamster against whole body sublethal irradiation. The purpose of this study is to test those antioxidant drugs, each of which has the capacity of inhibiting mucosal injury, as topical radioprotectants for the intestine. Material and Methods: The male hamsters were divided into the following four groups (n=6: group 1: control group, received saline, 1 ml/100 g by gavage, as placebo. Group 2: irradiated-control group, received whole body irradiation of 8 Gy as a single dose plus physiological saline. The animals in groups 3 and 4 were given a daily dose of 10 mg/kg of ibuprofen and 50 mg/kg of L-carnitine for 15 days respectively, before irradiation with a single dose of 8 Gy. Twenty-four hours after radiation exposure, the hamsters were sacrificed and samples were taken from the duodenum, and the histopatological determinations were carried out. Results: Morphologically, examination of the gamma irradiated duodenum revealed the presence of shortening and thickening of villi and flattening of enterocytes, massive subepithelial lifting. Pretreatment of ibuprofen and L-carnitine with irradiation reduced these histopathological changes. Conclusion: Ibuprofen and L-carnitine administrated by the oral route may be a good radioprotector against small intestinal damage in patients undergoing radiotherapy.

  19. Gamma-ray bursts from fast, galactic neutron stars

    International Nuclear Information System (INIS)

    Colgate, S.A.; Leonard, P.J.

    1996-01-01

    What makes a Galactic model of gamma-ray bursts (GBs) feasible is the observation of a new population of objects, fast neutron stars, that are isotropic with respect to the galaxy following a finite period, ∼30 My, after their formation (1). Our Galactic model for the isotropic component of GBs is based upon high-velocity neutron stars (NSs) that have accretion disks. These fast NSs are formed in tidally locked binaries, producing a unique population of high velocity (approx-gt 10 3 kms -1 ) and slowly rotating (8 s) NSs. Tidal locking occurs due to the meridional circulation caused by the conservation of angular momentum of the tidal lobes. Following the collapse to a NS and the explosion, these lobes initially perturb the NS in the direction of the companion. Subsequent accretion (1 to 2 s) occurs on the rear side of the initial motion, resulting in a runaway acceleration of the NS by neutrino emission from the hot accreted matter. The recoil momentum of the relativistic neutrino emission from the localized, down flowing matter far exceeds the momentum drag of the accreted matter. The recoil of the NS is oriented towards the companion, but the NS misses because of the pre-explosion orbital motion. The near miss captures matter from the companion and forms a disk around the NS. Accretion onto the NS from this initially gaseous disk due to the ''alpha'' viscosity results in a soft gamma-ray repeater phase, which lasts ∼10 4 yr. Later, after the neutron star has moved ∼30 kpc from its birthplace, solid bodies form in the disk, and accrete to planetoid size bodies after ∼3x10 7 years. Some of these planetoid bodies, with a mass of ∼10 21 endash 10 22 g, are perturbed into an orbit inside the tidal distortion radius of approx-gt 10 5 km. Of these ∼1% are captured by the magnetic field of the NS at R 3 km to create GBs

  20. Time-of-flight spectrometer for the measurement of gamma correlated neutron spectra

    International Nuclear Information System (INIS)

    Andriashin, A.V.; Devkin, B.V.; Lychagin, A.A.; Minko, J.V.; Mironov, A.N.; Nesterenko, V.S.; Sztaricskai, T.; Petoe, G.; Vasvary, L.

    1986-01-01

    A time-of-flight spectrometer for the measurement of gamma correlated neutron spectra from (n,xnγ) reactions is described. The operation and the main parameters are discussed. The resolution in the neutron channel is 2.2 ns/m at the 150 keV neutron energy threshold. A simultaneous measurement of the time-of-flight and amplitude distributions makes it possible to study gamma correlated neutron spectra as well as the prompt gamma spectra in coincidence with selected energy neutrons. In order to test the spectrometer, measurements of the neutron spectrum in coincidence with the 846 keV gamma line of 56 Fe were carried out at an incident neutron energy of 14.1 MeV. (Auth.)

  1. Simultaneous neutron and gamma spectrum adjustment

    International Nuclear Information System (INIS)

    Remec, I.

    1996-01-01

    The spectrum adjustment procedure was extended to simultaneous neutron and gamma spectrum adjustment, and the feasibility of this technique is demonstrated in the analysis of HFIR dosimetry experiments. Conditions in which gamma rays may contribute considerably to radiation damage in steels are discussed. Beryllium helium accumulation fluence monitors (HAFMs) were found to be good monitors in gamma fields of intensities high enough to contribute to steel embrittlement. Use of 237 Np, 238 U, and 9 Be HAFM as gamma dosimeters is proposed for high-dose irradiations in high-energy, high-intensity gamma fields

  2. Neutron capture prompt gamma-ray activation analysis at the NIST cold neutron research facility

    Energy Technology Data Exchange (ETDEWEB)

    Lindstrom, R M; Zeisler, R; Vincent, D H; Greenberg, R R; Stone, C A; Mackey, E A [National Inst. of Standards and Technology, Gaithersburg, MD (United States); Anderson, D L [Food and Drug Administration, Washington, DC (United States); Clark, D D [Cornell Univ., Ithaca, NY (United States)

    1993-01-01

    An instrument for neutron capture prompt gamma-ray activation analysis (PGAA) has been constructed as part of the Cold Neutron Research Facility at the 20 MW National Institute of Standards and Technology Research Reactor. The neutron fluence rate (thermal equivalent) is 1.5*10[sup 8] n*cm[sup -2]*s[sup -] [sup 1], with negligible fast neutrons and gamma-rays. With compact geometry and hydrogen-free construction, the sensitivity is sevenfold better than an existing thermal instrument. Hydrogen background is thirtyfold lower. (author) 17 refs.; 2 figs.

  3. 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)

  4. Comparison of gamma, neutron and proton irradiations of multimode fibers

    International Nuclear Information System (INIS)

    Gingerich, M.E.; Dorsey, K.L.; Askins, C.G.; Friebele, E.J.

    1987-01-01

    The effects of pure gamma, pure proton, and mixed neutron-gamma irradiation fields on a set of both pure and doped silica core multimode fibers have been investigated. Only slight differences are found in the radiation response of pure and doped silica core fibers exposed to gamma or mixed neutron-gamma fields, indicating that Co-60 sources can be used to simulate the effects of the mixed field (except in the case of a pure neutron environment). Although it is noted that neither mix field nor gamma sources adequately simulate the effects of proton irradiation of doped silica core fibers, a good correspondence is found in the case of the pure silica core waveguide. 13 references

  5. Effects of a whole body gamma irradiation on GABA repartition in infant rats cerebellum and hippocampal formation

    International Nuclear Information System (INIS)

    Menetrier, F.; Vernois, Y.; Court, L.

    1992-01-01

    'Full-Text:' Thirteen-day-old rats were exposed to a single dose of 4 or 0,5 Gy of gamma at a dose rate of 0,25 Gy/min and were killed about 5h after. Fixation was achieved in situ using glutaraldehyde. For GABA immunocytochemistry transversal sections were incubated with antiserum against GABA, then with PAP and revealed with diaminobenzidine. Proliferative layers are still observed in the infant rat cerebellum (external granular layer) and hippocampal formation (subgranular layer of the dentate gyrus). When irradiation occurs a high percent of these two layers cells are pycnotic. In the normal cerebellum, no immunostaining is observed in external granular layer cell bodies. The only labelled structures are few cytoplasmic expansions coming from subjacent layers. When irradiated, a strong GABA staining appears around pycnotic cells as a network with labelled meshes. GABA staining and pycnotic cells were more especially important when the irradiation increases. Further studies are needed to specify the nature of labelled meshes. In the normal hippocampal formation, subgranular cells are not GABA stained. Staining occurs in cells which are not granule cells. They are scattered throughout cell layers of the dentate gyrus with predominance in the hilus. After irradiation, GABA repartition is not modified. After a 4 Gy whole body gamma irradiation, the inhibitory GABA system is not injured. Other amino-acid neurotransmitters such as Glutamate could be modified. (author)

  6. Neutron Capture Gamma-Ray Spectroscopy. Proceedings of the International Symposium on Neutron Capture Gamma-Ray Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1969-11-15

    Experimental capabilities in the field of neutron capture gamma-ray spectroscopy have expanded greatly in the last few years; this has been due in large part to the advent of high-quality Ge(Li) detectors, improvements in electronic data processing, and improvements in bent-crystal spectrometers. Previously unsuspected phenomena, such as the '5. 5-MeV1 anomaly, have appeared and new research tools, such as neutron guide tubes, have been brought into use. Equally exciting developments have occurred in the theory of neutron capture. Complex spectra have yielded to analysis after account had been taken of such effects as vibration, rotation and Coriolis forces, and the theoretical prediction of capture spectra seems to be a future possibility. In view of the International Atomic Energy Agency's close interest in this subject and the need for an international exchange of ideas to analyse and study the latest developments, the organizers of the Symposium felt that work on neutron capture gamma-ray spectroscopy had achieved such valuable and significant results that the time had come for this information to be presented, examined and discussed internationally.

  7. Neutron Capture Gamma-Ray Spectroscopy. Proceedings of the International Symposium on Neutron Capture Gamma-Ray Spectroscopy

    International Nuclear Information System (INIS)

    1969-01-01

    Experimental capabilities in the field of neutron capture gamma-ray spectroscopy have expanded greatly in the last few years; this has been due in large part to the advent of high-quality Ge(Li) detectors, improvements in electronic data processing, and improvements in bent-crystal spectrometers. Previously unsuspected phenomena, such as the '5. 5-MeV1 anomaly, have appeared and new research tools, such as neutron guide tubes, have been brought into use. Equally exciting developments have occurred in the theory of neutron capture. Complex spectra have yielded to analysis after account had been taken of such effects as vibration, rotation and Coriolis forces, and the theoretical prediction of capture spectra seems to be a future possibility. In view of the International Atomic Energy Agency's close interest in this subject and the need for an international exchange of ideas to analyse and study the latest developments, the organizers of the Symposium felt that work on neutron capture gamma-ray spectroscopy had achieved such valuable and significant results that the time had come for this information to be presented, examined and discussed internationally

  8. Time-of-flight spectrometer for the measurement of gamma correlated neutron spectra

    International Nuclear Information System (INIS)

    Andryashin, A.V.; Devlein, B.V.; Lychagin, A.A.; Minko, Y.V.; Mironov, A.N.; Nesterenko, V.S.

    1986-01-01

    A time-of-flight spectrometer for the measurement of gamma correlated neutron spectra form (n,xnγ) reactions is described. The operation and the main parameters are discussed. The resolution in the neutron channel is 2.2 ns/m at the 150 keV neutron energy threshold. A simultaneous measurement of the time-of-flight and amplitude distributions makes it possible to study gamma correlated neutron spectra as well as the prompt gamma spectra in coincidence with selected energy neutrons. In order to test the spectrometer, measurements of the neutron spectrum in coincidence with the 846 keV gamma line of 56 Fe were carried out at an incident neutron energy of 14.1 MeV. (author). 3 figs., 6 refs

  9. Improved neutron-gamma discrimination for a 3He neutron detector using subspace learning methods

    Science.gov (United States)

    Wang, C. L.; Funk, L. L.; Riedel, R. A.; Berry, K. D.

    2017-05-01

    3He gas based neutron Linear-Position-Sensitive Detectors (LPSDs) have been used for many neutron scattering instruments. Traditional Pulse-height Analysis (PHA) for Neutron-Gamma Discrimination (NGD) resulted in the neutron-gamma efficiency ratio (NGD ratio) on the order of 105-106. The NGD ratios of 3He detectors need to be improved for even better scientific results from neutron scattering. Digital Signal Processing (DSP) analyses of waveforms were proposed for obtaining better NGD ratios, based on features extracted from rise-time, pulse amplitude, charge integration, a simplified Wiener filter, and the cross-correlation between individual and template waveforms of neutron and gamma events. Fisher Linear Discriminant Analysis (FLDA) and three Multivariate Analyses (MVAs) of the features were performed. The NGD ratios are improved by about 102-103 times compared with the traditional PHA method. Our results indicate the NGD capabilities of 3He tube detectors can be significantly improved with subspace-learning based methods, which may result in a reduced data-collection time and better data quality for further data reduction.

  10. Neutron and gamma irradiation effects on power semiconductor switches

    Science.gov (United States)

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

    1990-01-01

    The performance characteristics of high power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation.

  11. Dosimetry techniques of thermal neutrons and {gamma} radiation in reactor cores; Techniques de dosimetrie des neutrons thermiques et du rayonnement {gamma} dans les piles

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, J; Draganic, I; Hering, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    Chemical studies under radiation done in the reactor cores require to be followed by dosimetry. When the irradiations are done in the reflector, one can limit to the measure of the {gamma} and the neutron radiation. For the dosimetry of the {gamma} radiation, a dosimeter of ferrous sulfate is convenient until doses of about 10{sup 6} rep. The use of aired oxalic acid solutions permits to reach 10{sup 7} rep. The dosimetry of thermal neutrons has been made with solutions of cobalt sulphate or paper filter impregnated with this salt. The total chemical effect of the {gamma} and of the slow neutrons radiation is obtained with solutions of ferrous sulfate added with lithium sulphate. (M.B.) [French] Les etudes de chimie sous radiation faites dans les piles exigent d'etre suivies par dosimetrie. Lorsque les irradiations sont effectues dans le reflecteur, on peut se limiter a doser le rayonnement {gamma} et les neutrons. Pour la dosimetrie du rayonnement {gamma}, un dosimetre a sulfate ferreux convient jusqu'a des doses d'environ 10{sup 6} rep. L'emploi de solutions aerees d'acide oxalique permet d'atteindre 10{sup 7} rep. La dosimetrie des neutrons thermiques a ete faite avec des solutions de sulfate de cotalt ou du papier filtre impregne de ce sel. L'effet chimique total du rayonnement {gamma} et des neutrons lents est obtenu avec des solutions de sulfate ferreux additionne de sulfate de lithium. (M.B.)

  12. Effect of whole body neutron irradiation on certain enzyme activities in different brain areas in mice

    International Nuclear Information System (INIS)

    Kotb, M.A.; Ashour, A.M.; El-Bassiouni, E.A.

    1994-01-01

    Male swiss albino mice were exposed to whole-body irradiation by fast neutrons of 14 MeV average energy. Two single doses of 0.08 sievert and 0.16 sievert were used, corresponding to fluences of 1.27 X 10 8 and 2.54 X 10 8 n/cm 2 respectively. Two enzymes were assessed in different layers of the cerebrum and cerebellum of mouse brain. Changes in the activities of acid phosphatase (ACP) and succinic dehydrogenase (SDH) were taken to measure alterations in lysosomal and mitochondrial functions respectively. The degrees of lysosomal affection in different layers of the cerebrum were not uniform, while changes in A activity were very prominent in certain layers (e.g. external pyramidal layer, polymorphous cells layer and white matter), they were practically absent in others (e.g. internal pyramidal layer). Stronger effect was noted in the tissue layers of the cerebellum. The activity of SDH decreased as result of fast neutron irradiation. The response was more apparent for this enzyme than for ACP. This indicates more liability for a decrease in energy metabolism with consequent effect on behavioural and physiological functions under central nervous system control. 4 figs., 4 tabs

  13. Preliminary results of a neutron-gamma coincidence experiment

    International Nuclear Information System (INIS)

    Piercey, R.B.; Dunnam, F.E.; Muga, M.L.; Rester, A.C.; Ramayya, A.V.; Hamilton, J.H.; Eberth, J.; Zganjar, E.F.

    1984-01-01

    The recently completed neutron multiplicity detector dubbed PANDA (Pentagonal Annular Neutron Detector Array) is fully described later in this report. The new detector was recently used for the first time on-line at the Holifield Heavy Ion Research Facility to measure neutron-gamma coincidence in the 24 Mg( 58 Ni,xαypzn) reaction. The detector configuration for the experiment is shown. The PANDA was situated in the forward direction, coaxial to the beam line with five gamma-ray detectors placed at +/- 90 0 , +/- 135 0 , and 0 0 . 2 figures

  14. Measurements of prompt gamma-rays from fast-neutron induced fission with the LICORNE directional neutron source

    CERN Document Server

    Wilson, J N; Halipre, P; Oberstedt, S; Oberstedt, A

    2014-01-01

    At the IPN Orsay we have developed a unique, directional, fast neutron source called LICORNE, intended initially to facilitate prompt fission gamma measurements. The ability of the IPN Orsay tandem accelerator to produce intense beams of $^7$Li is exploited to produce quasi-monoenergetic neutrons between 0.5 - 4 MeV using the p($^7$Li,$^7$Be)n inverse reaction. The available fluxes of up to 7 × 10$^7$ neutrons/second/steradian for the thickest hydrogen-rich targets are comparable to similar installations, but with two added advantages: (i) The kinematic focusing produces a natural neutron beam collimation which allows placement of gamma detectors adjacent to the irradiated sample unimpeded by source neutrons. (ii) The background of scattered neutrons in the experimental hall is drastically reduced. The dedicated neutron converter was commissioned in June 2013. Some preliminary results from the first experiment using the LICORNE neutron source at the IPN Orsay are presented. Prompt fission gamma rays from fas...

  15. Gadolinium-Based GaN for Neutron Detection with Gamma Discrimination

    Science.gov (United States)

    2016-06-01

    Gadolinium-Based GaN for Neutron Detection with Gamma Discrimination Distribution Statement A. Approved for public release; distribution is...Final Technical Report BRBAA08-Per5-Y-1-2-0030 Title: “Gadolinium-Based GaN for Neutron Detection with Gamma Discrimination ” Grant...Analysis  .............................................................................................  23   6.   Gamma-ray Discrimination

  16. Self-Powered Neutron and Gamma Detectors for In-Core Measurements

    International Nuclear Information System (INIS)

    Strindehag, O.

    1971-11-01

    The performance of various types of self-powered neutron and gamma detectors intended for control and power distribution measurements in water cooled reactors is discussed. The self-powered detectors are compared with other types of in-core detectors and attention is paid to such properties as neutron and gamma sensitivity, high-temperature performance, burn-up rate and time of response. Also treated are the advantages and disadvantages of using gamma detector data for power distribution calculations instead of data from neutron detectors. With regard to neutron-sensitive detectors, results from several long-term experiments with vanadium and cobalt detectors are presented. The results include reliability and stability data for these two detector types and the Co build-up in cobalt detectors. Experimental results which reveal the fast response of cobalt detectors are presented, and the use of cobalt detectors in reactor safety systems is discussed. Experience of the design and installation of complete flux probes, electronic units and data processing systems for power reactors is reported. The investigation of gamma-sensitive detectors includes detectors with emitters of lead, zirconium, magnesium and Inconel. Measured gamma sensitivities from calibrations both in a reactor and in a gamma cell are given, and the signal levels of self-powered neutron and gamma detectors when applied to power reactors are compared

  17. Self-Powered Neutron and Gamma Detectors for In-Core Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Strindehag, O

    1971-11-15

    The performance of various types of self-powered neutron and gamma detectors intended for control and power distribution measurements in water cooled reactors is discussed. The self-powered detectors are compared with other types of in-core detectors and attention is paid to such properties as neutron and gamma sensitivity, high-temperature performance, burn-up rate and time of response. Also treated are the advantages and disadvantages of using gamma detector data for power distribution calculations instead of data from neutron detectors. With regard to neutron-sensitive detectors, results from several long-term experiments with vanadium and cobalt detectors are presented. The results include reliability and stability data for these two detector types and the Co build-up in cobalt detectors. Experimental results which reveal the fast response of cobalt detectors are presented, and the use of cobalt detectors in reactor safety systems is discussed. Experience of the design and installation of complete flux probes, electronic units and data processing systems for power reactors is reported. The investigation of gamma-sensitive detectors includes detectors with emitters of lead, zirconium, magnesium and Inconel. Measured gamma sensitivities from calibrations both in a reactor and in a gamma cell are given, and the signal levels of self-powered neutron and gamma detectors when applied to power reactors are compared

  18. 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

  19. Design innovations in neutron and gamma detectors

    International Nuclear Information System (INIS)

    Prasad, K.R.

    2003-01-01

    Neutron and gamma radiation needs to be monitored in most nuclear installations since it is highly penetrating. On-line monitoring of these radiations is very important for the safe and controlled operation of nuclear reactors, accelerators etc. Several design innovations have been carried out on gas ionisation detectors such as boron-lined proportional counters and ion chambers, fission detectors, gamma ion chambers as well as self-powered detectors. The use of additional structures within boron-lined detectors has enhanced their neutron sensitivity without a corresponding increase in the unwanted gamma sensitivity. The neutron sensitivity of fission counters can be enhanced by designing them as transmission line devices. Ion chambers with two and six pairs of electrodes have been developed for monitoring pulsed x-ray background at accelerator areas. Ion chambers have been employed at gamma fields up to 80 kR/h by deriving the exposure levels on-line using microcontroller devices programmed on the basis of theoretical and empirical formulas. The use of gas electron multiplier foils is proposed for charge multiplication in ion chambers. Self-powered detectors with new emitter materials like Hi, Ni and Inconel have been developed. (author)

  20. Neutron and/or gamma radiation detecting system

    International Nuclear Information System (INIS)

    Cerff, K.

    1985-01-01

    A large reception surface for the radiation to be detected is formed on a body of scintillation material (ZnS-AG with B matrix) which is adapted to convert neutron or gamma radiation into light energy. A large number of fiber light conductors is embedded in the body of scintillation material such that the fibers extend essentially parallel and fully across the reception surface of the body of scintillation material. The light energy, upon propagation along the fiber light conductors, is coupled into the conductors along the surface of the fibers which are unisotropic. This arrangement permits the use of unisotropic light conductor systems which provide for a separation of light collecting and light transmitting functions which results in a substantial reduction of light absorption losses during light transmission so that most of the light energy coupled into the fiber light conductors reaches the optoelectronic amplifier coupled to the end of the light conductors. (orig./HP) [de

  1. In vivo prompt gamma activation analysis facility for total body nitrogen and cadmium

    International Nuclear Information System (INIS)

    Munive, Marco; Solis, Jose; Revilla, Angel

    2008-01-01

    Full text: Prompt Neutron Activation Analysis (PGNAA) is a technique that could have medical applications, like determination of body's contents of protein and heavy metals in vivo. The in vivo PGNAA facility, contains a neutron source (Cf-252) with safety device, a compartment for animal irradiation, and a gamma rays detecting system based on the NaI(Tl) detector with an analytical software. The prompt gamma rays were emitted after 10 -15 s of the interaction, so they don't produce radioactive waste, and have a characteristics energy for each element, i.e. a strong peak at 2.24 MeV is observed for H. The facility has been used with laboratory mice. Water-filled phantom placed in the neutron beam was used to system calibration. Three study groups of 5 mice each one were selected and were feed with a different diet and the total body nitrogen (TBN) of the mice was monitored with the facility. The diet produced a different TBN for each group. Some mice drunk diluted water with Cl 2 Cd, so the presence of Cd was detected in the mouse. The minimum Cd concentration that the system can detect was 20 ppm. The total dose (neutron and gamma dose was measured from TLDs and simulated by MNCP-4B in the sample compartment during the irradiation time (5 minutes) is less than 2.5 mSv. This total dose is low than the dose from other analytical radiological techniques (25 a 50 mSv). (author)

  2. Simultaneous analysis of qualitative parameters of solid fuel using complex neutron gamma method

    International Nuclear Information System (INIS)

    Dombrovskij, V.P.; Ajtsev, N.I.; Ryashchikov, V.I.; Frolov, V.K.

    1983-01-01

    A study was made on complex neutron gamma method for simultaneous analysis of carbon content, ash content and humidity of solid fuel according to gamma radiation of inelastic fast neutron scattering and radiation capture of thermal neutrons. Metrological characteristics of pulse and stationary neutron gamma methods for determination of qualitative solid fuel parameters were analyzed, taking coke breeze as an example. Optimal energy ranges of gamma radiation detection (2-8 MeV) were determined. The advantages of using pulse neutron generator for complex analysis of qualitative parameters of solid fuel in large masses were shown

  3. Integrated neutron/gamma-ray portal monitors for nuclear safeguards

    International Nuclear Information System (INIS)

    Fehlau, P.E.

    1994-01-01

    Radiation monitoring is one nuclear-safeguards measure used to protect against the theft of special nuclear materials (SNM) by pedestrians departing from SNM access areas. The integrated neutron/gamma-ray portal monitor is an ideal radiation monitor for the task when the SNM is plutonium. It achieves high sensitivity for detecting both bare and shielded plutonium by combining two types of radiation detector. One type is a neutron-chamber detector, comprising a large, hollow, neutron moderator that contains a single thermal-neutron proportional counter. The entrance wall of each chamber is thin to admit slow neutrons from plutonium contained in a moderating shield, while the other walls are thick to moderate fast neutrons from bare or lead-shielded plutonium so that they can be detected. The other type of detector is a plastic scintillator that is primarily for detecting gamma rays from small amounts of unshielded plutonium. The two types of detector are easily integrated by making scintillators part of the thick back wall of each neutron chamber or by inserting them into each chamber void. The authors compared the influence of the two methods of integration on detecting neutrons and gamma rays, and they examined the effectiveness of other design factors and the methods for signal detection as well

  4. Development of advanced sensing system for antipersonnel mines with neutron capture gamma-ray analysis

    International Nuclear Information System (INIS)

    Iguchi, Tetsuo

    2006-01-01

    Neutron induced prompt gamma-ray analysis (NPGA) for survey of antipersonnel landmines is developed. A concept of sensor system with compact strong accelerator neutron source, simulation of detection and simulation results by trial examinations are stated. The measurement principles, objects, system construction, development of compact accelerator neutron source and high performance neutron capture gamma-ray detector, simulation of detection of landmine are reported. It can detect 10.8 MeV gamma-rays and estimate the incident angle of gamma-ray. Schematic layouts of the compact accelerator neutron resource, the compact Compton gamma camera and sensor unit, the estimation principle of incident angle of gamma-ray, experiments and comparison between the experimental results and the estimation results, a preliminary trial experiment system for sensing antipersonnel mines with neutron capture gamma-ray analysis are illustrated. (S.Y.)

  5. Repopulated antigen presenting cells induced an imbalanced differentiation of the helper T cells in whole body gamma irradiated mice

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hae Ran; Jo, Sung Kee [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Paik, Sang Kee [Chungnam National University, Taejon (Korea, Republic of)

    2004-07-01

    Therapeutic irradiation of cancer patients, although it may be protected by several antioxidant agents against free radicals, often induces chronic sequelae such as inflammation (allergic inflammation). This is a limiting factor for radiotherapy. Following radiotherapy, the inflammation or injury can occur in any organ with a high radiosensitivity such as the lung, bladder, kidney, liver, stomach and intestine. The mechanism by which ionizing radiation initiates inflammation is, however, poorly understood. In recent studies, it was suggested that a factor for irradiation-induced inflammation might be the over production of IL-4 that enhances fibroblast proliferation and collagen synthesis. During the early stages after irradiation, type 2 of the helper T cells might be the major source of IL-4, and later on there seems to be an activation of the other IL-4 producing cell types, e.q. macrophages or mast cells. This is interesting because inflammation is classically seen to be dominated by Th1 cells secreting IFN-{gamma}. In the previous study, we were interested in the enhancement of the IL-4 and the IgE production during the development of immune cells after {gamma}-irradiation. We were able to deduce that IL-4 production was increased because of the shifted differentiation of the naive Th cells by the repopulated antigen presenting cells after irradiation. The aim of the present study was to precisely define whether antigen-presenting cells (APCs) of whole body irradiation-treated mice could influence the shifted differentiation of the Th cells. This view can be demonstrated by confirming that the shifted functional status of the Th cells is induced by the altered function of the repopulated macrophages after whole body irradiation (WBI)

  6. Neutron and gamma sensitivities of self-powered detectors: Monte Carlo modelling

    Energy Technology Data Exchange (ETDEWEB)

    Vermeeren, Ludo [SCK-CEN, Nuclear Research Centre, Boeretang 200, B-2400 Mol, (Belgium)

    2015-07-01

    This paper deals with the development of a detailed Monte Carlo approach for the calculation of the absolute neutron sensitivity of SPNDs, which makes use of the MCNP code. We will explain the calculation approach, including the activation and beta emission steps, the gamma-electron interactions, the charge deposition in the various detector parts and the effect of the space charge field in the insulator. The model can also be applied for the calculation of the gamma sensitivity of self-powered detectors and for the radiation-induced currents in signal cables. The model yields detailed information on the various contributions to the sensor currents, with distinct response times. Results for the neutron sensitivity of various types of SPNDs are in excellent agreement with experimental data obtained at the BR2 research reactor. For typical neutron to gamma flux ratios, the calculated gamma induced SPND currents are significantly lower than the neutron induced currents. The gamma sensitivity depends very strongly upon the immediate detector surroundings and on the gamma spectrum. Our calculation method opens the way to a reliable on-line determination of the absolute in-pile thermal neutron flux. (authors)

  7. 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)

  8. Observation of neutron standing waves at total reflection by precision gamma spectroscopy

    International Nuclear Information System (INIS)

    Aksenov, V.L.; Gundorin, N.A.; Nikitenko, Yu.V.; Popov, Yu.P.; Cser, L.

    1998-01-01

    Total reflection of polarized neutrons from the layered structure glass/Fe (1000 A Angstrom)/Gd (50 A Angstrom) is investigated by registering neutrons and gamma-quanta from thermal neutron capture. The polarization ratio of gamma counts of neutron beams polarized in and opposite the direction of the magnetic field is measured. The polarization ratio is larger than unity for the neutron wavelengths λ 2.2 A Angstrom. Such behaviour of the wavelength dependence of the gamma-quanta polarization ratio points to the fact that over the surface of the Fe Layer a neutron standing wave caused by the interference of the incident neutron wave and the wave refracted from the magnetized Fe layer is formed

  9. [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.

  10. 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.

  11. Time-of-flight discrimination between gamma-rays and neutrons by using artificial neural networks

    International Nuclear Information System (INIS)

    Akkoyun, S.

    2013-01-01

    Highlights: ► Time-of-flight (tof) is an obvious method for separation between gamma and neutron particles. ► tof distributions are obtained by neural networks. ► Neural network method is consistent with the experimental results. ► Neural networks can classify different events for discrimination. - Abstract: In gamma-ray spectroscopy, a number of neutrons are emitted from the nuclei together with the gamma-rays. These neutrons influence gamma-ray spectra. An obvious method for discrimination between neutrons and gamma-rays is based on the time-of-flight (tof) technique. In this work, the tof distributions of gamma-rays and neutrons were obtained both experimentally and by using artificial neural networks (ANNs). It was shown that, ANN can correctly classify gamma-ray and neutron events. Also, for highly nonlinear detector response for tof, we have constructed consistent empirical physical formulas (EPFs) by appropriate ANNs. These ANN–EPFs can be used to derive further physical functions which could be relevant to discrimination between gamma-rays and neutrons

  12. Slow neutrons and secondary gamma ray distributions in concrete shields followed by reflecting layers

    International Nuclear Information System (INIS)

    Makarious, A.S.; Swilem, Y.I.; Awwad, Z.; Bayomy, T.

    1993-01-01

    Slow neutrons and secondary gamma ray distributions in concrete shields with and without a reflecting layer behind layer behind the concrete shield have been investigated first in case of using a bare reactor beam and then on using a B-4 C filtered beam. The total and capture secondary gamma ray coefficient (B gamma and B gamma C ), the ratio of the reflected thermal neutron (gamma) the ratio of the secondary gamma rays caused by reflected neutrons to those caused transmitted neutrons (Th I gamma/F I gamma) and the effect of inserting a blocking layer (a B-4 C layer) between the concrete shield and the reflector on the suppression of the produced secondary gamma rays have been investigated. It was found that the presence of the reflector layer behind the concrete shield reflects some thermal neutrons back to the concrete shields and so it increases the number of thermal neutrons at the interface between the concrete shield and the reflector. Also the capture secondary gamma rays was increased at the interface between the two medii due to the capture of the reflected thermal neutrons in the concrete shields. It was shown that B-gamma is higher than and that B g amma B gamma C and I gamma T h/ I gamma i f for the different concrete types is higher in case of using the graphite reflector than that in using either water or paraffin reflectors. Putting a blocking layer (B 4 C layer) between the concrete shield and the reflector decreases the produced secondary gamma rays due to the absorption of the reflected thermal neutrons. 17 figs

  13. Radiation effect on silicon transistors in mixed neutrons-gamma environment

    Science.gov (United States)

    Assaf, J.; Shweikani, R.; Ghazi, N.

    2014-10-01

    The effects of gamma and neutron irradiations on two different types of transistors, Junction Field Effect Transistor (JFET) and Bipolar Junction Transistor (BJT), were investigated. Irradiation was performed using a Syrian research reactor (RR) (Miniature Neutron Source Reactor (MNSR)) and a gamma source (Co-60 cell). For RR irradiation, MCNP code was used to calculate the absorbed dose received by the transistors. The experimental results showed an overall decrease in the gain factors of the transistors after irradiation, and the JFETs were more resistant to the effects of radiation than BJTs. The effect of RR irradiation was also greater than that of gamma source for the same dose, which could be because neutrons could cause more damage than gamma irradiation.

  14. Change in concentration of inorganic phosphate and phosphocreatine in the rat diaphragm under the influence of whole-body gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mansour, M A; Gaber, M; Abdel-Fatah, K I

    1987-01-01

    The influence of irradiation on the concentration of creatine phosphate and inorganic phosphate in the diaphragm muscle were studied in rats exposed to 400 rad and 800 rad whole-body gamma radiation. The results showed that on the first day of post-exposure with 400 rad, the creatine phosphate concentration significantly increased, while the level significantly decreased on the third up to the fourteenth days of post exposure. In animals exposed to 800 rad, the diaphragm phosphocreatine showed a significant decrease on the first up to the ninth day post-irradiation as compared with the control group.

  15. Change in concentration of inorganic phosphate and phosphocreatine in the rat diaphragm under the influence of whole-body gamma irradiation

    International Nuclear Information System (INIS)

    Mansour, M.A.; Gaber, M.; Abdel-Fatah, K.I.

    1987-01-01

    The influence of irradiation on the concentration of creatine phosphate and inorganic phosphate in the diaphragm muscle were studied in rats exposed to 400 rad and 800 rad whole-body gamma radiation. The results showed that on the first day of post-exposure with 400 rad, the creatine phosphate concentration significantly increased, while the level significantly decreased on the third up to the fourteenth days of post exposure. In animals exposed to 800 rad, the diaphragm phosphocreatine showed a significant decrease on the first up to the ninth day post-irradiation as compared with the control group

  16. Neutron-gamma flux and dose calculations in a Pressurized Water Reactor (PWR)

    Science.gov (United States)

    Brovchenko, Mariya; Dechenaux, Benjamin; Burn, Kenneth W.; Console Camprini, Patrizio; Duhamel, Isabelle; Peron, Arthur

    2017-09-01

    The present work deals with Monte Carlo simulations, aiming to determine the neutron and gamma responses outside the vessel and in the basemat of a Pressurized Water Reactor (PWR). The model is based on the Tihange-I Belgian nuclear reactor. With a large set of information and measurements available, this reactor has the advantage to be easily modelled and allows validation based on the experimental measurements. Power distribution calculations were therefore performed with the MCNP code at IRSN and compared to the available in-core measurements. Results showed a good agreement between calculated and measured values over the whole core. In this paper, the methods and hypotheses used for the particle transport simulation from the fission distribution in the core to the detectors outside the vessel of the reactor are also summarized. The results of the simulations are presented including the neutron and gamma doses and flux energy spectra. MCNP6 computational results comparing JEFF3.1 and ENDF-B/VII.1 nuclear data evaluations and sensitivity of the results to some model parameters are presented.

  17. Neutron-gamma flux and dose calculations in a Pressurized Water Reactor (PWR

    Directory of Open Access Journals (Sweden)

    Brovchenko Mariya

    2017-01-01

    Full Text Available The present work deals with Monte Carlo simulations, aiming to determine the neutron and gamma responses outside the vessel and in the basemat of a Pressurized Water Reactor (PWR. The model is based on the Tihange-I Belgian nuclear reactor. With a large set of information and measurements available, this reactor has the advantage to be easily modelled and allows validation based on the experimental measurements. Power distribution calculations were therefore performed with the MCNP code at IRSN and compared to the available in-core measurements. Results showed a good agreement between calculated and measured values over the whole core. In this paper, the methods and hypotheses used for the particle transport simulation from the fission distribution in the core to the detectors outside the vessel of the reactor are also summarized. The results of the simulations are presented including the neutron and gamma doses and flux energy spectra. MCNP6 computational results comparing JEFF3.1 and ENDF-B/VII.1 nuclear data evaluations and sensitivity of the results to some model parameters are presented.

  18. 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

  19. Variation of Neutron Moderating Power on HDPE by Gamma Radiation

    International Nuclear Information System (INIS)

    Park, Kwang June; Ju, June Sik; Kang, Hee Young; Shin, Hee Sung; Kim, Ho Dong

    2009-01-01

    High density polyethylene (HDPE) is degraded due to a radiation-induced oxidation when it is used as a neutron moderator in a neutron counter for a nuclear material accounting of spent fuels. The HDPE exposed to the gamma-ray emitted from the fission products in a spent nuclear fuel results in a radiation-induced degradation which changes its original molecular structure to others. So a neutron moderating power variation of HDPE, irradiated by a gamma radiation, was investigated in this work. Five HDPE moderator structures were exposed to the gamma radiation emitted from a 60 Co source to a level of 10 5 -10 9 rad to compare their post-irradiation properties. As a result of the neutron measurement test with 5 irradiated HDPE structures and a neutron measuring system, it was confirmed that the neutron moderating power for the 105 rad irradiated HDPE moderator revealed the largest decrease when the un-irradiated pure one was used as a reference. It implies that a neutron moderating power variation of HDPE is not directly proportional to the integrated gamma dose rate. To clarify the cause of these changes, some techniques such as a FTIR, an element analysis and a densitometry were employed. As a result of these analyses, it was confirmed that the molecular structure of the gamma irradiated HDPEs had partially changed to others, and the contents of hydrogen and oxygen had varied during the process of a radiation-induced degradation. The mechanism of these changes cannot be explained in detail at present, and thus need further study

  20. Prompt gamma-based neutron dosimetry for Am-Be and other workplace neutron spectra

    International Nuclear Information System (INIS)

    Udupi, Ashwini; Panikkath, Priyada; Sarkar, P.K.

    2016-01-01

    A new field-deployable technique for estimating the neutron ambient dose equivalent H*(10) by using the measured prompt gamma intensities emitted from borated high-density polyethylene (BHDPE) and the combination of normal HDPE and BHDPE with different configurations have been evaluated in this work. Monte Carlo simulations using the FLUKA code has been employed to calculate the responses from the prompt gammas emitted due to the monoenergetic neutrons interacting with boron, hydrogen, and carbon nuclei. A suitable linear combination of these prompt gamma responses (dose conversion coefficient (DCC)-estimated) is generated to approximate the International Commission on Radiological Protection provided DCC using the cross-entropy minimization technique. In addition, the shape and configurations of the HDPE and BHDPE combined system are optimized using the FLUKA code simulation results. The proposed method is validated experimentally, as well as theoretically, using different workplace neutron spectra with a satisfactory outcome. (author)

  1. The Neutron-Gamma Pulse Shape Discrimination Method for Neutron Flux Detection in the ITER

    International Nuclear Information System (INIS)

    Xu Xiufeng; Li Shiping; Cao Hongrui; Yin Zejie; Yuan Guoliang; Yang Qingwei

    2013-01-01

    The neutron flux monitor (NFM), as a significant diagnostic system in the International Thermonuclear Experimental Reactor (ITER), will play an important role in the readings of a series of key parameters in the fusion reaction process. As the core of the main electronic system of the NFM, the neutron-gamma pulse shape discrimination (n-γ PSD) can distinguish the neutron pulse from the gamma pulse and other disturbing pulses according to the thresholds of the rising time and the amplitude pre-installed on the board, the double timing point CFD method is used to get the rising time of the pulse. The n-γ PSD can provide an accurate neutron count. (magnetically confined plasma)

  2. Neutron and gamma irradiation effects on power semiconductor switches

    International Nuclear Information System (INIS)

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

    1990-01-01

    The performance characteristics of high power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN bipolar junction transistors (BJTs), and metal-oxide-semiconductor field effect transistors (MOSFETs)

  3. Whole body gamma radiation effects on rheological behaviour (deformability) of rat erythrocytes

    International Nuclear Information System (INIS)

    Soliman, M.S.

    2004-01-01

    This study was designed to determine the effect of whole body gamma irradiation on the rheological behaviour of rat erythrocytes (deformability). Animals were divided into 4 irradiated groups and 4 control groups according to their sacrificing time intervals (1 st, 3 rd, 5 th and 7 th days) post-irradiation with dose (6 Gy). In all animals and at the previous time intervals, red blood cell (RBC) membrane proteins electrophoretic pattern, RBC membrane lipids levels (cholesterol and phospholipids), RBC electrolytes levels (sodium, potassium and calcium), corpuscular osmotic fragility and RBC morphological by scanning electron microscopy were determined. Highly significant increase in membrane cholesterol, RBC sodium, calcium and corpuscular osmotic fragility accompanied by highly significant decrease in membrane phospholipids, RBC potassium and RBC deformability were found. No changes in membrane proteins electrophoretic patterns were detected. Morphologically, there were increase in the incidences of echinocytes and spherocytes development, which were time dependent. According to the previous results, irradiation promotes alterations in RBC shape (echinocytosis), membrane skeletal dysfunction, membrane lipid peroxidation, increase in membrane cholesterol/phospholipid content, changes in membrane electrolyte permeability and decrease then increase in osmotic fragility. These alterations in turn led to decrease in cellular deformability as a result of increased membrane rigidity and also due to cells dehydration caused by excess leakage of potassium ions from the RBCs

  4. Whole-body counting in the Marshall Islands

    International Nuclear Information System (INIS)

    Sun, L.C.; Clinton, J.; Kaplan, E.; Meinhold, C.B.

    1991-01-01

    In 1978 the Marshall Islands Radiological Safety Program was organized to perform radiation measurements and assess radiation doses for the people of the Bikini, Enewetak, Rongelap and Utirik Atolls. One of the major field components of this program is whole- body counting (WBC). WBC is used to monitor the quantity of gamma- emitting radionuclides present in individuals. A primary objective of the program was to establish 137 Cesium body contents among the Enewetak, Rongelap and Utirik populations. 137 Cs was the only gamma-emitting fission radionuclide detected in the 1,967 persons monitored. 137 Cs body burdens tended to increase with age for both sexes, and were higher in males. The average 137 Cs dose Annual Effective Dose for the three populations was as follows: For Enewetak, the dose was 22±4 μSv. For Utirik, the dose was 33± 3 μSv. Since 1985 the Rongelap people have been self-exiled to Mejatto. Biological elimination should have reduced their dose to virtually zero, and the measured dose was 2±2 μSv. If they had remained on Rongelap Island, the calculated dose would have been 99 μSv, which is about one-third of the background dose. 7 refs., 1 tab

  5. Whole Body Counters (rev.)

    Energy Technology Data Exchange (ETDEWEB)

    Woodburn, John H. [Walter Johnson High School, Rockville, MD; Lengemann, Frederick W. [Cornell University

    1967-01-01

    Whole body counters are radiation detecting and measuring instruments that provide information about the human body. This booklet describes different whole body counters, scientific principles that are applied to their design, and ways they are used.

  6. 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)

  7. Preliminary study about frequencies of unstable chromosome alterations induced by gamma beam and neutron-gamma mixed field

    International Nuclear Information System (INIS)

    Mendes, Mariana E.; Souza, Priscilla L.G.; Brandao, Jose Odinilson de C.; Santos, Joelan A.L.; Vilela, Eudice C.; Lima, Fabiana F.; Calixto, Merilane S.; Santos, Neide

    2011-01-01

    The estimate on approximate dose in exposed individual can be made through conventional cytogenetic analysis of dicentric, this technique has been used to support physical dosimetry. It is important to estimate the absorbed dose in case of accidents with the aim of developing an appropriate treatment and biological dosimetry can be very useful in case where the dosimetry is unavailable. Exposure to gamma and neutron radiation leads to the same biological effects such as chromosomal alterations and cancer. However, neutrons cause more genetic damage, such as mutation or more structural damage, such as chromosome alterations. The aim of research is to compare frequencies of unstable chromosome alterations induced by a gamma beam with those from neutron-gamma mixed field. Two blood samples were obtained from one healthy donor and irradiated at different sources. The first sample was exposed to mixed field neutron-gamma sources 241 AmBe at the Neutron Calibration Laboratory (NCL - CRCN/NE - PE - Brazil) and the second one was exposed to 137 Cs gamma rays at 137 Cs Laboratory (CRCN/NE - PE - Brazil), both exposures resulting in an absorbed dose of 0.66Gy. Mitotic metaphase cells were obtained by lymphocyte culture for chromosomal analysis and slides were stained with Giemsa 5%. These preliminary results showed a similarity in associated dicentrics frequency per cell (0.041 and 0.048) after 137 Cs and 241 AmBe sources irradiations, respectively. However, it was not observed centric rings frequency per cell (0.0 and 0.027). This study will be continue to verify the frequencies of unstable chromosome alterations induced by only gamma beam and neutron-gamma mixed field. (author)

  8. Preliminary study about frequencies of unstable chromosome alterations induced by gamma beam and neutron-gamma mixed field

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, Mariana E.; Souza, Priscilla L.G.; Brandao, Jose Odinilson de C.; Santos, Joelan A.L.; Vilela, Eudice C.; Lima, Fabiana F. [Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Calixto, Merilane S.; Santos, Neide [Universidade Federal de Pernanmbuco (CCB/UFPE), Recife, PE (Brazil). Centro de Ciencias Biologicas. Dept. de Genetica

    2011-07-01

    The estimate on approximate dose in exposed individual can be made through conventional cytogenetic analysis of dicentric, this technique has been used to support physical dosimetry. It is important to estimate the absorbed dose in case of accidents with the aim of developing an appropriate treatment and biological dosimetry can be very useful in case where the dosimetry is unavailable. Exposure to gamma and neutron radiation leads to the same biological effects such as chromosomal alterations and cancer. However, neutrons cause more genetic damage, such as mutation or more structural damage, such as chromosome alterations. The aim of research is to compare frequencies of unstable chromosome alterations induced by a gamma beam with those from neutron-gamma mixed field. Two blood samples were obtained from one healthy donor and irradiated at different sources. The first sample was exposed to mixed field neutron-gamma sources {sup 241}AmBe at the Neutron Calibration Laboratory (NCL - CRCN/NE - PE - Brazil) and the second one was exposed to {sup 137}Cs gamma rays at {sup 137}Cs Laboratory (CRCN/NE - PE - Brazil), both exposures resulting in an absorbed dose of 0.66Gy. Mitotic metaphase cells were obtained by lymphocyte culture for chromosomal analysis and slides were stained with Giemsa 5%. These preliminary results showed a similarity in associated dicentrics frequency per cell (0.041 and 0.048) after {sup 137}Cs and {sup 241}AmBe sources irradiations, respectively. However, it was not observed centric rings frequency per cell (0.0 and 0.027). This study will be continue to verify the frequencies of unstable chromosome alterations induced by only gamma beam and neutron-gamma mixed field. (author)

  9. Neutron and gamma dose and spectra measurements on the Little Boy replica

    International Nuclear Information System (INIS)

    Hoots, S.; Wadsworth, D.

    1984-01-01

    The radiation-measurement team of the Weapons Engineering Division at Lawrence Livermore National Laboratory (LLNL) measured neutron and gamma dose and spectra on the Little Boy replica at Los Alamos National Laboratory (LANL) in April 1983. This assembly is a replica of the gun-type atomic bomb exploded over Hiroshima in 1945. These measurements support the National Academy of Sciences Program to reassess the radiation doses due to atomic bomb explosions in Japan. Specifically, the following types of information were important: neutron spectra as a function of geometry, gamma to neutron dose ratios out to 1.5 km, and neutron attenuation in the atmosphere. We measured neutron and gamma dose/fission from close-in to a kilometer out, and neutron and gamma spectra at 90 and 30 0 close-in. This paper describes these measurements and the results. 12 references, 13 figures, 5 tables

  10. ZZ AIRFEWG, Gamma, Neutron Transport Calculation in Air Using FEWG1 Cross-Section

    International Nuclear Information System (INIS)

    1985-01-01

    1 - Description of program or function: Format: ANISN; Number of groups: 37 neutron / 21 gamma-ray; Nuclides: air (79% N and 21% O); Origin: DLC-0031/FEWG1 cross sections (ENDF/B-IV). Weighting spectrum: 1/E. The AIRFEWG library has been generated by an ANISN multigroup calculation of gamma-ray, neutron, and secondary gamma-ray transport in infinite homogeneous air using DLC-0031/FEWG1 cross sections. 2 - Method of solution: The results were generated with a P3, ANISN run with a source in a single energy group. Thus, 58 such runs were required. For sources in the 37 neutron groups, both neutron and secondary gamma-ray fluence results were calculated. For gamma-ray sources only gamma-ray fluences were calculated

  11. Gamma ray attenuation coefficient measurement for neutron-absorbent materials

    Energy Technology Data Exchange (ETDEWEB)

    Jalali, Majid [Isfahan Nuclear Science and Technology Research Institute (NSTRT), Reactor and Accelerators Research and Development School, Atomic Energy Organization (Iran, Islamic Republic of)], E-mail: m_jalali@entc.org.ir; Mohammadi, Ali [Faculty of Science, Department of Physics, University of Kashan, Km. 6, Ravand Road, Kashan (Iran, Islamic Republic of)

    2008-05-15

    The compounds Na{sub 2}B{sub 4}O{sub 7}, H{sub 3}BO{sub 3}, CdCl{sub 2} and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the {gamma} rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H{sub 3}BO{sub 3} with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds.

  12. GEANT4 simulation study of a gamma-ray detector for neutron resonance densitometry

    International Nuclear Information System (INIS)

    Tsuchiya, Harufumi; Harada, Hideo; Koizumi, Mitsuo; Kitatani, Fumito; Takamine, Jun; Kureta, Masatoshi; Iimura, Hideki

    2013-01-01

    A design study of a gamma-ray detector for neutron resonance densitometry was made with GEANT4. The neutron resonance densitometry, combining neutron resonance transmission analysis and neutron resonance capture analysis, is a non-destructive technique to measure amounts of nuclear materials in melted fuels of the Fukushima Daiichi nuclear power plants. In order to effectively quantify impurities in the melted fuels via prompt gamma-ray measurements, a gamma-ray detector for the neutron resonance densitometry consists of cylindrical and well type LaBr 3 scintillators. The present simulation showed that the proposed gamma-ray detector suffices to clearly detect the gamma rays emitted by 10 B(n, αγ) reaction in a high environmental background due to 137 Cs radioactivity with its Compton edge suppressed at a considerably small level. (author)

  13. Determination of planetary surfaces elemental composition by gamma and neutron spectroscopy

    International Nuclear Information System (INIS)

    Diez, B.

    2009-06-01

    Measuring the neutron and gamma ray fluxes produced by the interaction of galactic cosmic rays with planetary surfaces allow constraining the chemical composition of the upper tens of centimeters of material. Two different angles are proposed to study neutron and gamma spectroscopy: data processing and data interpretation. The present work is in line with two experiments, the Mars Odyssey Neutron Spectrometer (MONS) and the Selene Gamma Ray Spectrometer. A review of the processing operations applied to the MONS dataset is proposed. The resulting dataset is used to determine the depth of the hydrogen deposits below the Martian surface. In water depleted regions, neutron data allow constraining the concentration in elements likely to interact with neutrons. The confrontation of these results to those issued from the Gamma Ray Spectrometer onboard Mars Odyssey provides interesting insight on the geologic context of the Central Elysium Planitia region. These martian questions are followed by the study of the Selene gamma ray data. Although only preliminary processing has been done to date, qualitative lunar maps of major elements (Fe, Ca, Si, Ti, Mg, K, Th, U) have already been realized. (author)

  14. A Comparison of Molecular and Histopathological Changes in Mouse Intestinal Tissue Following Whole-Body Proton- or Gamma-Irradiation

    Science.gov (United States)

    Purgason, Ashley; Mangala, Lingegowda; Zhang, Ye; Hamilton, Stanley; Wu, Honglu

    2010-01-01

    There are many consequences following exposure to the space radiation environment which can adversely affect the health of a crew member. Acute radiation syndrome (ARS) involving nausea and vomiting, damage to radio-sensitive tissue such as the blood forming organs and gastrointestinal tract, and cancer are some of these negative effects. The space radiation environment is ample with protons and contains gamma rays as well. Little knowledge exists to this point, however, regarding the effects of protons on mammalian systems; conversely several studies have been performed observing the effects of gamma rays on different animal models. For the research presented here, we wish to compare our previous work looking at whole-body exposure to protons using a mouse model to our studies of mice experiencing whole-body exposure to gamma rays as part of the radio-adaptive response. Radio-adaptation is a well-documented phenomenon in which cells exposed to a priming low dose of radiation prior to a higher dose display a reduction in endpoints like chromosomal aberrations, cell death, micronucleus formation, and more when compared to their counterparts receiving high dose-irradiation only. Our group has recently completed a radio-adaptive experiment with C57BL/6 mice. For both this study and the preceding proton research, the gastrointestinal tract of each animal was dissected four hours post-irradiation and the isolated small intestinal tissue was fixed in formalin for histopathological examination or snap-frozen in liquid nitrogen for RNA isolation. Histopathologic observation of the tissue using standard H&E staining methods to screen for morphologic changes showed an increase in apoptotic lesions for even the lowest doses of 0.1 Gy of protons and 0.05 Gy of gamma rays, and the percentage of apoptotic cells increased with increasing dose. A smaller percentage of crypts showed 3 or more apoptotic lesions in animals that received 6 Gy of gamma-irradiation compared to mice

  15. Using a Borated Panel to Form a Dual Neutron-Gamma Detector

    Energy Technology Data Exchange (ETDEWEB)

    Scott Wilde; Raymond Keegan

    2008-06-20

    A borated polyethylene plane placed between a neutron source and a gamma spectrometer is used to form a dual neutron-gamma detection system. The polyethylene thermalizes the source neutrons so that they are captured by {sup 10}B to produce a flux of 478 keV gamma-rays that radiate from the plane. This results in a buildup of count rate in the detector over that from a disk of the same diameter as the detector crystal (same thickness as the panel). Radiation portal systems are a potential application of this technique.

  16. Effect of whole-body gamma radiation on tissue sulfhydryl contents in experimental rats

    International Nuclear Information System (INIS)

    Sarkar, S.R.; Singh, L.R.; Uniyal, B.P.

    1985-01-01

    It has been postulated that vital constituents of cell membranes concerned with the maintenance of cellular integrity are affected by ionizing radiation. Sulfhydryl contents, which form an integral component of cell membranes play vital roles in maintaining cellular integrity. The purpose was to evaluate non-protein and protein sulfhydryl contents in tissues of irradiated rats. Adult male Sprague Dawley rats were exposed to whole-body gamma irradiation of 4 Gy and 10 Gy and non-protein and protein sulfhydryl contents of blood, heart and spleen were studied on postirradiation day 1, 3 and 6. Both groups of experimental rats exhibited unchanged blood non-protein sulfhydryl contents on first day after irradiation with significant diminution subsequently. In contrast, blood protein sulfhydryl groups of both groups of rats were increased on first day post exposure, which became normal on sixth day. Myocardial non-protein and protein sulfhydryl contents of both groups of rats remained unchanged in the initial stage of radiation exposure indicating radioresistance nature of rat heart. Both groups of rats demonstrated biphasic nature of non-protein sulfhydryl contents in spleen, asrevealed by initial increase with subsequent decrease. Protein sulfhydryl contents of rats of 4 Gy group showed significant diminution post exposure throughout, while the same of 10 Gy behaved in opposite way. (author)

  17. Serotonin exerting protection of serum lipid pattern in male albino rat subjected to shot or intermittent whole body gamma irradiation

    International Nuclear Information System (INIS)

    El-Dighidy, E.A.M.; El-Kady, M.H.R.

    1995-01-01

    Certain cancer patients are subjected to varying levels of intermittent radiation delivered in certain cases as whole body exposure. Effective control of many haematological complications built up during radiation treatment would necessarily contribute to up-grading of cancer radiotherapy. In the present study, the effect of either shot or intermittent whole body gamma irradiation at cumulative dose levels up to 6 and 10 Gy, have been evaluated on the levels of total lipids and lipid fractions in blood serum of male albino rats. The pharmacological role of serotonin and its potential radioprotective capacity have been assessed on the serum lipid pattern. The results indicated generally significant increases in the levels of blood lipid fractions especially HDL-cholesterol. On the other hand, the level of LDL-cholesterol recorded a significant decrease on the third day post either shot or cumulative dose levels at 6 or 10 Gy and also post 4 successive doses of serotonin administration. The only exceptions were recorded in the case of LDL-cholesterol post administration of single dose of serotonin and serotonin prior to shot dose levels of 6 or 10 Gy. 2 tabs

  18. Energy–angle correlation of neutrons and gamma-rays emitted from an HEU source

    Energy Technology Data Exchange (ETDEWEB)

    Miloshevsky, G., E-mail: gennady@purdue.edu; Hassanein, A.

    2014-06-01

    Special Nuclear Materials (SNM) yield very unique fission signatures, namely correlated neutrons and gamma-rays. A major challenge is not only to detect, but also to rapidly identify and recognize SNM with certainty. Accounting for particle multiplicity and correlations is one of standard ways to detect SNM. However, many parameter data such as joint distributions of energy, angle, lifetime, and multiplicity of neutrons and gamma-rays can lead to better recognition of SNM signatures in the background radiation noise. These joint distributions are not well understood. The Monte Carlo simulations of the transport of neutrons and gamma-rays produced from spontaneous and interrogation-induced fission of SNM are carried out using the developed MONSOL computer code. The energy spectra of neutrons and gamma-rays from a bare Highly Enriched Uranium (HEU) source are investigated. The energy spectrum of gamma-rays shows spectral lines by which HEU isotopes can be identified, while those of neutrons do not show any characteristic lines. The joint probability density function (JPDF) of the energy–angle association of neutrons and gamma-rays is constructed. Marginal probability density functions (MPDFs) of energy and angle are derived from JPDF. A probabilistic model is developed for the analysis of JPDF and MPDFs. This probabilistic model is used to evaluate mean values, standard deviations, covariance and correlation between the energy and angle of neutrons and gamma-rays emitted from the HEU source. For both neutrons and gamma-rays, it is found that the energy–angle variables are only weakly correlated.

  19. Intercalibration of CDTN and IRD whole body counters

    International Nuclear Information System (INIS)

    Dantas, B.M.; Dantas, A.L.A.; Alonso, T.C.

    2008-01-01

    Full text: Intercalibration exercises are designed to harmonize analytical techniques and ensure reliability of measurement results performed in a laboratory network. Such strategy helps to improve laboratory performance among participants in future intercomparison exercises, when it is verified the metrological capacity, by determining accuracy, precision and reproducibility of data produced by each laboratory. In Brazil, there are currently four in vivo monitoring systems, located in IRD, in Rio de Janeiro, CDTN, in Belo Horizonte, IPEN, in Sao Paulo and CNAAA, in Angra dos Reis. Such systems, generically referred as whole body counters, aim to detect and quantify radionuclides in organs and tissues for radiological protection purposes and to provide useful information for studies on biokinetic behavior of radionuclides in humans and animals. The objective of this work is to establish a methodology to be applied for intercalibration of whole body counters. The IRD whole body counter is installed in a 15 cm steel shielded room where two NaI(Tl) and four HPGe detectors are calibrated for the determination of radionuclides in the energy range from 10 to 3000 keV. The CDTN whole body counter has one NaI detector set up in a shadow shield configuration, and is able to determine radionuclides emitting photons from 100 to 2000 keV. The intercalibration exercise described in this work was planed for whole body geometry using the scintillation detectors available in both laboratories. It was used a thin glass vial containing 2,6615 g of a solution of four gamma emitters ( 57 Co, 137 Cs, 54 Mn, 65 Zn), supplied by the National Laboratory for Metrology of Ionizing Radiation (LNMRI-IRD). The glass vial was measured in the same geometry in both IRD and CDTN whole body counters, being positioned at 31,5 cm distance from the NaI(Tl) detector of each laboratory. The calibration curves (photo peak channel and Efficiency vs Energy) of each detection system were compared. The

  20. Gamma-Ray Bursts from Neutron Star Kicks

    Science.gov (United States)

    Huang, Y. F.; Dai, Z. G.; Lu, T.; Cheng, K. S.; Wu, X. F.

    2003-09-01

    The idea that gamma-ray bursts might be a phenomenon associated with neutron star kicks was first proposed by Dar & Plaga. Here we study this mechanism in more detail and point out that the neutron star should be a high-speed one (with proper motion larger than ~1000 km s-1). It is shown that the model agrees well with observations in many aspects, such as the energetics, the event rate, the collimation, the bimodal distribution of durations, the narrowly clustered intrinsic energy, and the association of gamma-ray bursts with supernovae and star-forming regions. We also discuss the implications of this model on the neutron star kick mechanism and suggest that the high kick speed was probably acquired as the result of the electromagnetic rocket effect of a millisecond magnetar with an off-centered magnetic dipole.

  1. Optimized Design of Spacing in Pulsed Neutron Gamma Density Logging While Drilling

    Directory of Open Access Journals (Sweden)

    ZHANG Feng;HAN Zhong-yue;WU He;HAN Fei

    2016-10-01

    Full Text Available Radioactive source, used in traditional density logging, has great impact on the environment, while the pulsed neutron source applied in the logging tool is more safety and greener. In our country, the pulsed neutron-gamma density logging technology is still in the stage of development. Optimizing the parameters of neutron-gamma density instrument is essential to improve the measuring accuracy. This paper mainly studied the effects of spacing to typical neutron-gamma density logging tool which included one D-T neutron generator and two gamma scintillation detectors. The optimization of spacing were based on measuring sensitivity and counting statistic. The short spacing from 25 to 35 cm and long spacing from 60 to 65 cm were selected as the optimal position for near and far detector respectively. The result can provide theoretical support for design and manufacture of the instrument.

  2. 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.

  3. Analysis of unstable chromosome alterations frequency induced by neutron-gamma mixed field radiation

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Priscilla L.G.; Brandao, Jose Odinilson de C.; Vale, Carlos H.F.P.; Santos, Joelan A.L.; Vilela, Eudice C.; Lima, Fabiana F. [Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil)], e-mail: psouza@cnen.gov.br, e-mail: jodinilson@cnen.gov.br; Calixto, Merilane S.; Santos, Neide [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Genetica

    2009-07-01

    Nowadays monitoring chromosome alterations in peripheral blood lymphocytes have been used to access the radiation absorbed dose in individuals exposed accidental or occupationally to gamma radiation. However there are not many studies based on the effects of mixed field neutron-gamma. The radiobiology of neutrons has great importance because in nuclear factories worldwide there are several hundred thousand individuals monitored as potentially receiving doses of neutron. In this paper it was observed the frequencies of unstable chromosome alterations induced by a gamma-neutron mixed field. Blood was obtained from one healthy donor and exposed to mixed field neutron-gamma sources {sup 241}AmBe (20 Ci) at the Neutron Calibration Laboratory (NCL-CRCN/NE-PE-Brazil). The chromosomes were observed at metaphase, following colcemid accumulation and 1000 well-spread metaphases were analyzed for the presence of chromosome alterations by two experienced scorers. The results suggest that there is the possibility of a directly proportional relationship between absorbed dose of neutron-gamma mixed field radiation and the frequency of unstable chromosome alterations analyzed in this paper. (author)

  4. Analysis of unstable chromosome alterations frequency induced by neutron-gamma mixed field radiation

    International Nuclear Information System (INIS)

    Souza, Priscilla L.G.; Brandao, Jose Odinilson de C.; Vale, Carlos H.F.P.; Santos, Joelan A.L.; Vilela, Eudice C.; Lima, Fabiana F.; Calixto, Merilane S.; Santos, Neide

    2009-01-01

    Nowadays monitoring chromosome alterations in peripheral blood lymphocytes have been used to access the radiation absorbed dose in individuals exposed accidental or occupationally to gamma radiation. However there are not many studies based on the effects of mixed field neutron-gamma. The radiobiology of neutrons has great importance because in nuclear factories worldwide there are several hundred thousand individuals monitored as potentially receiving doses of neutron. In this paper it was observed the frequencies of unstable chromosome alterations induced by a gamma-neutron mixed field. Blood was obtained from one healthy donor and exposed to mixed field neutron-gamma sources 241 AmBe (20 Ci) at the Neutron Calibration Laboratory (NCL-CRCN/NE-PE-Brazil). The chromosomes were observed at metaphase, following colcemid accumulation and 1000 well-spread metaphases were analyzed for the presence of chromosome alterations by two experienced scorers. The results suggest that there is the possibility of a directly proportional relationship between absorbed dose of neutron-gamma mixed field radiation and the frequency of unstable chromosome alterations analyzed in this paper. (author)

  5. Deficiency in Monte Carlo simulations of coupled neutron-gamma-ray fields

    NARCIS (Netherlands)

    Maleka, Peane P.; Maucec, Marko; de Meijer, Robert J.

    2011-01-01

    The deficiency in Monte Carlo simulations of coupled neutron-gamma-ray field was investigated by benchmarking two simulation codes with experimental data. Simulations showed better correspondence with the experimental data for gamma-ray transport only. In simulations, the neutron interactions with

  6. Thin film CdTe based neutron detectors with high thermal neutron efficiency and gamma rejection for security applications

    Energy Technology Data Exchange (ETDEWEB)

    Smith, L.; Murphy, J.W. [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Kim, J. [Korean Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of); Rozhdestvenskyy, S.; Mejia, I. [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Park, H. [Korean Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of); Allee, D.R. [Flexible Display Center, Arizona State University, Phoenix, AZ 85284 (United States); Quevedo-Lopez, M. [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Gnade, B., E-mail: beg031000@utdallas.edu [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States)

    2016-12-01

    Solid-state neutron detectors offer an alternative to {sup 3}He based detectors, but suffer from limited neutron efficiencies that make their use in security applications impractical. Solid-state neutron detectors based on single crystal silicon also have relatively high gamma-ray efficiencies that lead to false positives. Thin film polycrystalline CdTe based detectors require less complex processing with significantly lower gamma-ray efficiencies. Advanced geometries can also be implemented to achieve high thermal neutron efficiencies competitive with silicon based technology. This study evaluates these strategies by simulation and experimentation and demonstrates an approach to achieve >10% intrinsic efficiency with <10{sup −6} gamma-ray efficiency.

  7. Feasibility study on using imaging plates to estimate thermal neutron fluence in neutron-gamma mixed fields

    International Nuclear Information System (INIS)

    Fujibuchi, T.; Tanabe, Y.; Sakae, T.; Terunuma, T.; Isobe, T.; Kawamura, H.; Yasuoka, K.; Matsumoto, T.; Harano, H.; Nishiyama, J.; Masuda, A.; Nohtomi, A.

    2011-01-01

    In current radiotherapy, neutrons are produced in a photonuclear reaction when incident photon energy is higher than the threshold. In the present study, a method of discriminating the neutron component was investigated using an imaging plate (IP) in the neutron-gamma-ray mixed field. Two types of IP were used: a conventional IP for beta- and gamma rays, and an IP doped with Gd for detecting neutrons. IPs were irradiated in the mixed field, and the photo-stimulated luminescence (PSL) intensity of the thermal neutron component was discriminated using an expression proposed herein. The PSL intensity of the thermal neutron component was proportional to thermal neutron fluence. When additional irradiation of photons was added to constant neutron irradiation, the PSL intensity of the thermal neutron component was not affected. The uncertainty of PSL intensities was approximately 11.4 %. This method provides a simple and effective means of discriminating the neutron component in a mixed field. (authors)

  8. Gamma rays from fast neutron capture in silicon and sulphur

    International Nuclear Information System (INIS)

    Lindholm, A.; Nilsson, L.; Bergqvist, I.

    1975-01-01

    Gamma-ray spectra from neutron capture in natural samples of silicon and sulphur have been recorded at eight neutron energies between 4 and 15 MeV. Time-of-flight techniques were used to improve the signal-to-background ratio and the gamma radiation was detected by a large NaI(Tl) scintillator. Cross sections have been determined for transitions to individual (or groups of) levels in the final nucleus. Calculations based on the direct-semidirect model show that this model gives a reasonable description of the shapes of the gamma-ray spectra, but fails to account for observed excitation functions. The inclusion of the compound-nucleus capture process gives a conclusive improvement in the description of the excitation functions, in particular at low neutron energies. The ability of the compound-nucleus model to account for the shapes of the gamma-ray spectra is as good as that of the direct-semidirect model. At higher neutron energies, an improvement is obtained for transitions to the region of weakly bound levels, where the single-particle structure is poorly known. (Auth.)

  9. 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

  10. Evaluation of gamma and neutron irradiation effects on the properties of mica film capacitors

    International Nuclear Information System (INIS)

    Roy, Rajesh; Pandya, Arun

    2005-01-01

    We present an investigation of gamma and neutron radiation effects on mica film capacitors from an electrical point of view. We have studied quantitatively the effects of gamma and neutron irradiation on mica film capacitors of thickness, 20 and 40 μm (0.7874 and 1.5748 mil) with two different areas, 01 and 04 cm 2 . The capacitance has been measured at room temperature in the frequency range 100 Hz-10 MHz. Negligible change in the capacitance due to high gamma dose of 60 Co, 15 kGy at dose rate 0.25 kGy/h, has been observed. However, appreciable change in the capacitance has been observed due to low doses of fast neutrons (cumulative dose, 115 cGy) with flux ∼ 9.925 X 10 7 neutrons/cm 2 h from 252 Cf neutron source of fluence, 2.5 x 10 7 neutrons/s. We have also observed that the impact of gamma and neutron irradiation is more at frequencies higher than 10 kHz, These results show that the mica capacitors do not show any radiation response below 10 kHz. The study shows the radiation response of mica film capacitors to gamma and fast neutron radiations. Mica capacitors show low gamma radiation response in comparison to fast neutron radiation, because a total dose of kGy order has been given by gamma source and only few cGy dose has been given by fast neutron source. (author)

  11. Analysis of coupled neutron-gamma radiations, applied to shieldings in multigroup albedo method

    International Nuclear Information System (INIS)

    Dunley, Leonardo Souza

    2002-01-01

    The principal mathematical tools frequently available for calculations in Nuclear Engineering, including coupled neutron-gamma radiations shielding problems, involve the full Transport Theory or the Monte Carlo techniques. The Multigroup Albedo Method applied to shieldings is characterized by following the radiations through distinct layers of materials, allowing the determination of the neutron and gamma fractions reflected from, transmitted through and absorbed in the irradiated media when a neutronic stream hits the first layer of material, independently of flux calculations. Then, the method is a complementary tool of great didactic value due to its clarity and simplicity in solving neutron and/or gamma shielding problems. The outstanding results achieved in previous works motivated the elaboration and the development of this study that is presented in this dissertation. The radiation balance resulting from the incidence of a neutronic stream into a shielding composed by 'm' non-multiplying slab layers for neutrons was determined by the Albedo method, considering 'n' energy groups for neutrons and 'g' energy groups for gammas. It was taken into account there is no upscattering of neutrons and gammas. However, it was considered that neutrons from any energy groups are able to produce gammas of all energy groups. The ANISN code, for an angular quadrature order S 2 , was used as a standard for comparison of the results obtained by the Albedo method. So, it was necessary to choose an identical system configuration, both for ANISN and Albedo methods. This configuration was six neutron energy groups and eight gamma energy groups, using three slab layers (iron aluminum - manganese). The excellent results expressed in comparative tables show great agreement between the values determined by the deterministic code adopted as standard and, the values determined by the computational program created using the Albedo method and the algorithm developed for coupled neutron-gamma

  12. Whole-body γ-irradiation effects on catecholamine concentration in animal tissues

    International Nuclear Information System (INIS)

    Makashev, Zh.K.; Uteshev, T.A.; Abylaev, Zh. A.; Zhurnist, A.G.

    2003-01-01

    On the whole-body gamma-radiation activity in the exchanges of catecholamines (adrenalin and non-adrenalin) and their predecessors (dopamine and DOPA) in the rats tissue organism, indicate the infringement of irradiated animals in different links of biological synthesis the bio-gen amines in different phases of the radiation: DOPA→dopamine, dopamine→adrenalin, adrenalin→non-adrenalin. (author)

  13. System and plastic scintillator for discrimination of thermal neutron, fast neutron, and gamma radiation

    Science.gov (United States)

    Zaitseva, Natalia P.; Carman, M. Leslie; Faust, Michelle A.; Glenn, Andrew M.; Martinez, H. Paul; Pawelczak, Iwona A.; Payne, Stephen A.

    2017-05-16

    A scintillator material according to one embodiment includes a polymer matrix; a primary dye in the polymer matrix, the primary dye being a fluorescent dye, the primary dye being present in an amount of 3 wt % or more; and at least one component in the polymer matrix, the component being selected from a group consisting of B, Li, Gd, a B-containing compound, a Li-containing compound and a Gd-containing compound, wherein the scintillator material exhibits an optical response signature for thermal neutrons that is different than an optical response signature for fast neutrons and gamma rays. A system according to one embodiment includes a scintillator material as disclosed herein and a photodetector for detecting the response of the material to fast neutron, thermal neutron and gamma ray irradiation.

  14. Detection of fast neutrons in a plastic scintillator using digital pulse processing to reject gammas

    International Nuclear Information System (INIS)

    Reeder, P.L.; Peurrung, A.J.; Hansen, R.R.; Stromswold, D.C.; Hensley, W.K.; Hubbard, C.W.

    1999-01-01

    We report on neutron-gamma discrimination in a plastic scintillator based on the time delay inherent in second and third chance neutron scattering. Because of the time delay (∼3 ns) between the first and second scattering of a neutron, calculations of gammas and neutrons in a plastic scintillator predict that a neutron signal should be significantly broader than a pulse from a gamma event. Experimentally, we have used a fast digital oscilloscope coupled to a computer to examine individual pulses from neutron or gamma induced signals in fast scintillators coupled to a fast PMT. Individual neutron-induced signals were consistent with the predictions of our model, but gamma pulses were broader than expected. We present various tests to understand this phenomenon and discuss a way to overcome this problem

  15. Measurements of keV-neutron capture {gamma} rays of fission products. 3

    Energy Technology Data Exchange (ETDEWEB)

    Igashira, Masayuki [Tokyo Inst. of Tech. (Japan). Research Lab. for Nuclear Reactors

    1997-03-01

    {gamma} rays from the keV-neutron capture reactions by {sup 143,145}Nd and {sup 153}Eu have been measured in a neutron energy region of 10 to 80 keV, using a large anti-Compton NaI(Tl) {gamma}-ray spectrometer and the {sup 7}Li(p,n){sup 7}Be pulsed neutron source with a 3-MV Pelletron accelerator. The preliminary results for the capture cross sections and {gamma}-ray spectra of those nuclei are presented and discussed. (author)

  16. RPL-SC dosimetric system for measuring gamma and neutron irradiation in case of emergency

    International Nuclear Information System (INIS)

    Khristova, M. G.

    1993-01-01

    A RPL-SC dosimetric system is designed based on radiophotoluminescence (RPL) and on the effect of fast neutron bombardment of silicon semiconductor (SC) diodes. The experimental prototype consists of a computerized automatic measurement system and an individual dosimetric cassette accommodating RPL and SC detectors. The equipment includes: a device for measurement of the direct voltage of Si diodes and the RPL light emitted by RPL detectors; a compartment with dosimetric cassettes to be measured; a manipulator with three positions executing automatic measurement of cassettes; a computer and a printer. The system operates in both manual and automatic modes. In the manual mode each step of the manipulator is set up by the operator who changes the ranges after they have been filled to capacity and registers the results. In the automatic mode the whole process of maintaining the supply and control voltage, of manipulator's operation, measuring, data recording and data processing are controlled by a specially designed computer programme. Main technical parameters: 1) Measurement range of absorbed dose: gamma rays - 10 -3 to 10 2 Gy; thermal neutrons - 10 -3 to 10 2 Gy; fast neutrons - 10 to 30 Gy. 2) Energy range: gamma rays - 0.04 to 1.25 MeV; thermal neutrons - 0.024 eV; fast neutrons - 0.3 to 14 MeV. 3) Relative measurement error - ±15% 4) Recurrent measurement of one and the same dose. 5) Measurement time of 1 detector - 15 sec. (author)

  17. Biogenic amines in brain areas of rats and response to varying dose levels of whole body gamma irradiation

    International Nuclear Information System (INIS)

    Abdelhamid, F.M.; Elmossalamy, N.; Othman, S.A.; Roushdy, H.M.; Abdelraheem, K.

    1994-01-01

    The levels of norepinephrine (NE), dopamine (DA), 5-hydroxy-tryptamine (5-HT) and 5-hydroxy-indole acetic acid (5-HIAA) were examined in the brain areas:cortex,: cerebellum, striatum and pons in rats exposed to whole body gamma-irradiation at the dose levels 6.5 and 10 Gy. The data obtained indicated that: 6.5 Gy induced in all brain areas, a slight increase in 5-HT concomitant with significant decrease in NE, DA levels, besides a significant increase in 5-HTAA in cerebellum and pons. After the dose 10 Gy the maximum excitation of 5-HT level was in striatum whereas declines in NE, DA were recorded in all brain areas. 5-HIAA displayed significant increase in cerebellum and pons and maximum decline in the cortex. 4 tab

  18. Use of prompt gamma emissions from polyethylene to estimate neutron ambient dose equivalent

    Energy Technology Data Exchange (ETDEWEB)

    Priyada, P.; Sarkar, P.K., E-mail: pradip.sarkar@manipal.edu

    2015-06-11

    The possibility of using measured prompt gamma emissions from polyethylene to estimate neutron ambient dose equivalent is explored theoretically. Monte Carlo simulations have been carried out using the FLUKA code to calculate the response of a high density polyethylene cylinder to emit prompt gammas from interaction of neutrons with the nuclei of hydrogen and carbon present in polyethylene. The neutron energy dependent responses of hydrogen and carbon nuclei are combined appropriately to match the energy dependent neutron fluence to ambient dose equivalent conversion coefficients. The proposed method is tested initially with simulated spectra and then validated using experimental measurements with an Am–Be neutron source. Experimental measurements and theoretical simulations have established the feasibility of estimating neutron ambient dose equivalent using measured neutron induced prompt gammas emitted from polyethylene with an overestimation of neutron dose at very low energies. - Highlights: • A new method for estimating H{sup ⁎}(10) using prompt gamma emissions from HDPE. • Linear combination of 2.2 MeV and 4.4 MeV gamma intensities approximates DCC (ICRP). • Feasibility of the method was established theoretically and experimentally. • The response of the present technique is very similar to that of the rem meters.

  19. 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

  20. Two-dimensional neutron scintillation detector with optimal gamma discrimination

    International Nuclear Information System (INIS)

    Kanyo, M.; Reinartz, R.; Schelten, J.; Mueller, K.D.

    1993-01-01

    The gamma sensitivity of a two-dimensional scintillation neutron detector based on position sensitive photomultipliers (Hamamatsu R2387 PM) has been minimized by a digital differential discrimination unit. Since the photomultiplier gain is position-dependent by ±25% a discrimination unit was developed where digital upper and lower discrimination levels are set due to the position-dependent photomultiplier gain obtained from calibration measurements. By this method narrow discriminator windows can be used to reduce the gamma background drastically without effecting the neutron sensitivity of the detector. The new discrimination method and its performance tested by neutron measurements will be described. Experimental results concerning spatial resolution and γ-sensitivity are presented

  1. Evaluation of the neutron and gamma-ray production cross-sections for 55Mn

    International Nuclear Information System (INIS)

    Takahashi, H.

    1974-11-01

    The evaluation of neutron and gamma production cross sections for manganese-55 from 1.0 (10) -5 eV to 20.0 MeV for ENDF/ B-IV is summarized. Included are resonance parameters, neutron cross sections, angular and energy distribution of secondary neutrons, gamma multiplicities and transition probability array, gamma angular and energy distributions, nuclear model calculations, uncertainty estimates of cross sections, and evaluated cross sections. (U.S.)

  2. Gamma ray attenuation coefficient measurement for neutron-absorbent materials

    International Nuclear Information System (INIS)

    Jalali, Majid; Mohammadi, Ali

    2008-01-01

    The compounds Na 2 B 4 O 7 , H 3 BO 3 , CdCl 2 and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the γ rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H 3 BO 3 with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds

  3. PANDORA, a large volume low-energy neutron detector with real-time neutron-gamma discrimination

    Science.gov (United States)

    Stuhl, L.; Sasano, M.; Yako, K.; Yasuda, J.; Baba, H.; Ota, S.; Uesaka, T.

    2017-09-01

    The PANDORA (Particle Analyzer Neutron Detector Of Real-time Acquisition) system, which was developed for use in inverse kinematics experiments with unstable isotope beams, is a neutron detector based on a plastic scintillator coupled to a digital readout. PANDORA can be used for any reaction study involving the emission of low energy neutrons (100 keV-10 MeV) where background suppression and an increased signal-to-noise ratio are crucial. The digital readout system provides an opportunity for pulse shape discrimination (PSD) of the detected particles as well as intelligent triggering based on PSD. The figure of merit results of PANDORA are compared to the data in literature. Using PANDORA, 91 ± 1% of all detected neutrons can be separated, while 91 ± 1% of the detected gamma rays can be excluded, reducing the gamma ray background by one order of magnitude.

  4. Neutron and gamma-ray spectra of 239PuBe and 241AmBe

    International Nuclear Information System (INIS)

    Vega-Carrillo, H.R.; Manzanares-Acuna, Eduardo; Becerra-Ferreiro, A.M.; Carrillo-Nunez, Aureliano

    2002-01-01

    Neutron and gamma-ray spectra of 239 PuBe and 241 AmBe were measured and their dosimetric features were calculated. Neutron spectra were measured using a multisphere neutron spectrometer with a 6 LiI(Eu) scintillator. The 239 PuBe neutron spectrum was measured in an open environment, while the 241 AmBe neutron spectrum was measured in a closed environment. Gamma-ray spectra were measured using a NaI(Tl) scintillator using the same experimental conditions for both sources. The effect of measuring conditions for the 241 AmBe neutron spectrum indicates the presence of epithermal and thermal neutrons. The low-resolution neutron spectra obtained with the multisphere spectrometer allows one to calculate the dosimetric features of neutron sources. At 100 cm both sources produce approximately the same count rate as that of the 4.4 MeV gamma-ray per unit of alpha emitter activity

  5. Rrol of Zinc Cystenine in the Regulation of Metallothionnein Induction in whole body gamma irradiation rats

    International Nuclear Information System (INIS)

    Azab, Kh. Sh.; Zaharn, A.M.; Noaman, E.

    2004-01-01

    The antioxidant competence of metallothionein (MT) in cellular injury lunched by free radicals released in view of ionizing radiation has been proposed. The present work was conducted to elucidate the role of Zinc cysteine in the regulation of metallothionein induction in whole body gamma irradiated rats. cysteine was delivered to rats via intraperitoneal (i.p) injection at a concentration of 25-mg/kg body weight/day for two successive 2 days. The second injection was 30- min. pre irradiation. Whole body γ- irradiation at dose level 6.5 Gy induced significant increase in the levels of metallothionein in all investigated tissues (serum, liver and kidney) accompanied with significant increase in the levels of Zn in the liver. Cu concentrations increased in serum and kidney and decreased significantly in liver tissues. Data of lipid peroxidation demonstrated significant increase in TBARS as compared with control valuws in serum, liver and kidney. Iron was decreased significantly in serum and liver but a significant increase was recorded in kidney at 7 days after irradiation. Ca increased significantly in the liver only as compared with control rats. In addition, K concentration increased significantly in serum, liver and kidney while, P increased in serum and liver when compared with control values. The administration of zinc cysteine pre-irradiation induces significant increases in liver metallothionin from irradiated rat's value. It is only serum show significant decrease in level of MT from the irradiated rat's value on the 1st day post irradiation. However, the changes observed in the levels of Zn, Cu, Iron and Ca, K and P are less manifested when compared with values of irradiated animals. The reduction in the levels of TBARS was obvious comparing with irradiated rat's data. The amelioration occurred in the levels of Zn, Cu, Fe, Ca, P and K when, zinc cysteine administrated before irradiation postulate the positive role zinc cysteine in the adjustment of

  6. Neutron-induced 2.2 MeV background in gamma ray telescopes

    International Nuclear Information System (INIS)

    Zanrosso, E.M.; Long, J.L.; Zych, A.D.; White, R.S.; Hughes Aircraft Co., Los Angeles, CA)

    1985-01-01

    Neutron-induced gamma ray production is an important source of background in Compton scatter gamma ray telescopes where organic scintillator material is used. Most important is deuteron formation when atmospheric albedo and locally produced neutrons are thermalized and subsequently absorbed in the hydrogenous material. The resulting 2.2 MeV gamma line essentially represents a continuous isotropic source within the scintillator itself. Interestingly, using a scintillator material with a high hydrogen-to-carbon ratio to minimize the neutron-induced 4.4 MeV carbon line favors the np reaction. The full problem of neutron-induced background in Compton scatter telescopes has been previously discussed. Results are presented of observations with the University of California balloon-borne Compton scatter telescope where the 2.2 MeV induced line emission is prominently seen

  7. Bismuth- and lithium-loaded plastic scintillators for gamma and neutron detection

    International Nuclear Information System (INIS)

    Cherepy, Nerine J.; Sanner, Robert D.; Beck, Patrick R.; Swanberg, Erik L.; Tillotson, Thomas M.; Payne, Stephen A.; Hurlbut, Charles R.

    2015-01-01

    Transparent plastic scintillators based on polyvinyltoluene (PVT) have been fabricated with high loading of bismuth carboxylates for gamma spectroscopy, and with lithium carboxylates for neutron detection. When activated with a combination of standard fluors, 2,5-diphenyloxazole (PPO) and tetraphenylbutadiene (TPB), gamma light yields with 15 wt% bismuth tripivalate of 5000 Ph/MeV are measured. A PVT plastic formulation including 30 wt% lithium pivalate and 30 wt% PPO offers both pulse shape discrimination, and a neutron capture peak at ~400 keVee. In another configuration, a bismuth-loaded PVT plastic is coated with ZnS( 6 Li) paint, permitting simultaneous gamma and neutron detection via pulse shape discrimination with a figure-of-merit of 3.8, while offering gamma spectroscopy with energy resolution of R(662 keV)=15%

  8. Biophysical study of mice blood after whole body irradiation

    Science.gov (United States)

    Saad El Din, Alsha A.; Desouky, Omar S.; El Behay, Amin Z.; El Sayed, Anwar A.

    1996-05-01

    The immediate of whole body fractionated doses of 137Cs gamma rays totalling 13 Gy on mice as well as the late effects of accumulative dose of 10 Gy (8 days after exposure) were studied. Changes due to gamma irradiation in hemoglobin conductivity and buffer capacity indicate the appearance of hydrophobic groups and changes in hydrophilic/hydrophobic ratio. These changes demonstrate different degrees of unfolding and refolding of the hemoglobin molecule. The viscosity coefficient of hemoglobin is found to increase at fractionated doses of 7 and 13 Gy. Such effect seems to be due to aggregation of the protein part of hemoglobin. The fractionated dose of 13 Gy causes changes in the electronic state of oxyhemoglobin indicated by an increase in methemoglobin which reduces biological activity.

  9. A compact neutron beam generator system designed for prompt gamma nuclear activation analysis.

    Science.gov (United States)

    Ghassoun, J; Mostacci, D

    2011-08-01

    In this work a compact system was designed for bulk sample analysis using the technique of PGNAA. The system consists of (252)Cf fission neutron source, a moderator/reflector/filter assembly, and a suitable enclosure to delimit the resulting neutron beam. The moderator/reflector/filter arrangement has been optimised to maximise the thermal neutron component useful for samples analysis with a suitably low level of beam contamination. The neutron beam delivered by this compact system is used to irradiate the sample and the prompt gamma rays produced by neutron reactions within the sample elements are detected by appropriate gamma rays detector. Neutron and gamma rays transport calculations have been performed using the Monte Carlo N-Particle transport code (MCNP5). 2010 Elsevier Ltd. All rights reserved.

  10. Method and apparatus for neutron induced gamma ray logging for lithology identification

    International Nuclear Information System (INIS)

    Oliver, D.W.; Culver, R.B.

    1981-01-01

    The patent describes a neutron-gamma well logging technique which can distinguish between sandstone and limestone formations irrespective of water salinity in the formation. The formation surrounding a borehole is irradiated by fast neutrons and the resulting gamma rays are counted. The gamma rays are converted to electrical signals in three distinct steps; the first two signals result from gamma rays associated with calcium content of the formation and the third signal from gamma rays associated with silicon content. Gamma rays resulting from irradiation of calcium are counted at two non-contiguous energy bands. (O.T.)

  11. Unilateral irradiation of pigs in a mixed neutrons+gamma field. Early results

    International Nuclear Information System (INIS)

    Lemaitre, Guy; Maas, Jean.

    1982-08-01

    Pigs (16-20kg) were irradiated with 60 Co gamma or in a mixed field (neutron + gamma from the pulsed reactor SILENE). Pigs were unilaterally exposed by the left side. Each experimental group was composed of twelve animals and one control. Within the dose range explored (reference dose is mid-line tissue dose): 4-9.8 Gy of gamma rays only; 4.6 - 5.7 Gy of neutrons and gamma rays, pigs presented the haematopioetic form of the acute radiation sickness. At 5 Gy mixed field was more harmful than gamma rays only. Therefore the numerical value of neutron RBE (lethality 50 p cent within 30 days) is more than one. Experiments will be carried out in order to determine RBE values more accurately. Bone marrow dose will also be determined [fr

  12. Assessment of the radiomodifying effect of the herbal preparation 'Elixir-3' in laboratory animals exposed to external whole-body gamma irradiation

    International Nuclear Information System (INIS)

    Tenchova, V.; Topalova, S.; Stefanova, D.; Kuzova, K.

    2002-01-01

    The study of preparations obtained from natural products, free of any toxic effects on the organism, has important practical implications on the prophylaxis against and correction of eventual sequelae of ionizing radiation. It is the purpose of the study to assay the radiomodifying action of the herbal preparation 'Elixir-3' (E-3) on mice exposed to acute whole-body irradiation with 3 and 7 Gy gamma-rays, using a prophylactic-therapeutic scheme of application over 30 days. E-3 represents alcohol-water extract of basil, hops, briar, nettle, walnut and peppermint. Bone marrow femoral and spleen cellularity, endogenous spleen colony-forming units (E-CFUs), overall plasma oxidation activity and phagocytic activity of neutrophils are evaluated. E-3, administered in a prophylactic-therapeutic scheme, promotes post-radiation recovery of hematopoiesis in mice irradiated with non-lethal and median-lethal gamma ray doses, and exerts a favourable effect on the anti-oxidation status and phagocytic activity of neutrophils in laboratory animals.(authors)

  13. AMPX: a modular code system for generating coupled multigroup neutron-gamma libraries from ENDF/B

    Energy Technology Data Exchange (ETDEWEB)

    Greene, N.M.; Lucius, J.L.; Petrie, L.M.; Ford, W.E. III; White, J.E.; Wright, R.Q.

    1976-03-01

    AMPX is a modular system for producing coupled multigroup neutron-gamma cross section sets. Basic neutron and gamma cross-section data for AMPX are obtained from ENDF/B libraries. Most commonly used operations required to generate and collapse multigroup cross-section sets are provided in the system. AMPX is flexibly dimensioned; neutron group structures, and gamma group structures, and expansion orders to represent anisotropic processes are all arbitrary and limited only by available computer core and budget. The basic processes provided will (1) generate multigroup neutron cross sections; (2) generate multigroup gamma cross sections; (3) generate gamma yields for gamma-producing neutron interactions; (4) combine neutron cross sections, gamma cross sections, and gamma yields into final ''coupled sets''; (5) perform one-dimensional discrete ordinates transport or diffusion theory calculations for neutrons and gammas and, on option, collapse the cross sections to a broad-group structure, using the one-dimensional results as weighting functions; (6) plot cross sections, on option, to facilitate the ''evaluation'' of a particular multigroup set of data; (7) update and maintain multigroup cross section libraries in such a manner as to make it not only easy to combine new data with previously processed data but also to do it in a single pass on the computer; and (8) output multigroup cross sections in convenient formats for other codes. (auth)

  14. Tangential channel for nuclear gamma-resonance spectroscopy in thermal neutron capture

    International Nuclear Information System (INIS)

    Belogurov, V.N.; Bondars, H.Ya.; Lapenas, A.A.; Reznikov, R.S.; Senkov, P.E.

    1979-01-01

    Design of a tangential reactor channel which has been made to replace the radial one in the pulsed research reactor IRT-2000 is described. It allows to use the same hole in biological reactor schielding. Characteristics of neutron and gamma-background spectra at the excit of the channel are given and compared with analogous characteristics of the radial one. The gamma background in the tangential channel is lower than in the radial channel. The gamma spectra in the Gd 155 (n, γ)Gd 156 , Gd 157 (n, γ)Gd 158 , Er 167 (n, γ)Er 168 and Hf 177 (n, γ)Hf 178 reactions show that the application of X-ray detection units BDR with the tangential channel allows to carry out the gamma spectrometry of gamma quanta emitted in the thermal neutron capture by both high and low neutron capture cross section nuclei (e.g., Gdsup(157, 155) and Er 167 , Hf 177 , respectively)

  15. Non-destructive assay of mechanical components using gamma-rays and thermal neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Erica Silvani; Avelino, Mila R. [PPG-EM/UERJ, R. Sao Francisco Xavier, 524, Maracana - Rio de Janeiro - RJ (Brazil); Almeida, Gevaldo L. de; Souza, Maria Ines S. [IEN/CNEN, Rua Helio de Almeida, 75, Ilha do Fundao, Rio de Janeiro - RJ (Brazil)

    2013-05-06

    This work presents the results obtained in the inspection of several mechanical components through neutron and gamma-ray transmission radiography. The 4.46 Multiplication-Sign 10{sup 5} n.cm{sup -2}.s{sup -1} thermal neutron flux available at the main port of the Argonauta research reactor in Instituto de Engenharia Nuclear has been used as source for the neutron radiographic imaging. The 412 keV {gamma}-ray emitted by {sup 198}Au, also produced in that reactor, has been used as interrogation agent for the gamma radiography. Imaging Plates - IP specifically designed to operate with thermal neutrons or with X-rays have been employed as detectors and storage devices for each of these radiations.

  16. Effect of a non lethal whole-body gamma irradiation on the spontaneous and evoked electroencephalographic activities of the adult rabbit

    International Nuclear Information System (INIS)

    Court, L.

    1969-01-01

    The whole of the experimental methods described (animal preparation, achievement of a precise physiological technique, dosimetry, biological information processing) allowed us to follow the changes for 15 days in the spontaneous and evoked electroencephalogram activities of rabbits submitted to a non-lethal 400 rads whole-body gamma-irradiation. Behavioural troubles, changes in the arousal state and the spontaneous electrical activity of the neo-cortex and hippocampus were noticed constantly together with an enhanced cortical excitability, and the appearance of elements of the paroxystic series sometimes in contrast with a general decrease in amplitude. After a visual stimulus the general morphology of evoked activities at the level of the primary visual areas and hippocampus was unchanged, but enhanced latencies and delays, less systematic modifications in amplitudes seemed to show out a direct effect of radiations on the nervous system and sensorial activities; these troubles seemed to occur independently from the basic electrical activity. As a whole, the changes observed were usually transitory and varied with each individual. Finally an assumption is made to explain the mechanism of arousal troubles and the general evolution of spontaneous electrical activity in the brain. (author) [fr

  17. Application of neutron-gamma analysis for determination of C/N ratio in compost

    Science.gov (United States)

    Neutron-gamma analysis is based on the acquisition of gamma rays from neutron irradiated study objects. The intensity and energy of the registered gamma rays gives information on the types and amounts of elements in the studied object. The use of this method for measurements of soil carbon demonstra...

  18. Whole-body MRI screening

    Energy Technology Data Exchange (ETDEWEB)

    Puls, Ralf [HELIOS Klinikum Erfurt (Germany). Inst. of Diagnostic and Interventional Radiology and Neuroradiology; Hosten, Norbert (ed.) [Universitaetsklinikum Greifswald (Germany). Diagnostic Radiology and Neuroradiology

    2014-07-01

    The advent of dedicated whole-body MRI scanners has made it possible to image the human body from head to toe with excellent spatial resolution and with the sensitivity and specificity of conventional MR systems. A comprehensive screening examination by MRI relies on fast image acquisition, and this is now feasible owing to several very recent developments, including multichannel techniques, new surface coil systems, and automatic table movement. The daily analysis of whole-body MRI datasets uncovers many incidental findings, which are discussed by an interdisciplinary advisory board of physicians from all specialties. This book provides a systematic overview of these incidental findings with the aid of approximately 240 high-quality images. The radiologists involved in the project have written chapters on each organ system, presenting a structured compilation of the most common findings, their morphologic appearances on whole-body MRI, and guidance on their clinical management. Chapters on technical and ethical issues are also included. It is hoped that this book will assist other diagnosticians in deciding how to handle the most common incidental findings encountered when performing whole-body MRI.

  19. Whole-body MRI screening

    International Nuclear Information System (INIS)

    Puls, Ralf; Hosten, Norbert

    2014-01-01

    The advent of dedicated whole-body MRI scanners has made it possible to image the human body from head to toe with excellent spatial resolution and with the sensitivity and specificity of conventional MR systems. A comprehensive screening examination by MRI relies on fast image acquisition, and this is now feasible owing to several very recent developments, including multichannel techniques, new surface coil systems, and automatic table movement. The daily analysis of whole-body MRI datasets uncovers many incidental findings, which are discussed by an interdisciplinary advisory board of physicians from all specialties. This book provides a systematic overview of these incidental findings with the aid of approximately 240 high-quality images. The radiologists involved in the project have written chapters on each organ system, presenting a structured compilation of the most common findings, their morphologic appearances on whole-body MRI, and guidance on their clinical management. Chapters on technical and ethical issues are also included. It is hoped that this book will assist other diagnosticians in deciding how to handle the most common incidental findings encountered when performing whole-body MRI.

  20. Effect of bifidobacteria implantation on the survival time of whole-body irradiated mice

    International Nuclear Information System (INIS)

    Yokokura, Teruo; Onoue, Masaharu; Mutai, Masahiko

    1980-01-01

    Letahl dose (2 KR) of gamma-ray was irradiated on the whole bodies of mice. Survival time after irradiation was significantly longer in mice with administration of both Bifidobacterium breve YIT 4008 and transgalactosyl oligosaccharide than in mice with administration of either of the two or nothing. (Tsunoda, M.)

  1. Sparse image representation for jet neutron and gamma tomography

    Energy Technology Data Exchange (ETDEWEB)

    Craciunescu, T. [EURATOM-MEdC Association, Institute for Laser, Plasma and Radiation Physics, Bucharest (Romania); Kiptily, V. [EURATOM/CCFE Association, Culham Science Centre, Abingdon (United Kingdom); Murari, A. [Consorzio RFX, Associazione EURATOM-ENEA per la Fusione, Padova (Italy); Tiseanu, I.; Zoita, V. [EURATOM-MEdC Association, Institute for Laser, Plasma and Radiation Physics, Bucharest (Romania)

    2013-10-15

    Highlights: •A new tomographic method for the reconstruction of the 2-D neutron and gamma emissivity on JET. •The method is based on the sparse representation of the reconstructed image in an over-complete dictionary. •Several techniques, based on a priori information are used to regularize this highly limited data set tomographic problem. •The proposed method provides good reconstructions in terms of shapes and resolution. -- Abstract: The JET gamma/neutron profile monitor plasma coverage of the emissive region enables tomographic reconstruction. However, due to the availability of only two projection angles and to the coarse sampling, tomography is a highly limited data set problem. A new reconstruction method, based on the sparse representation of the reconstructed image in an over-complete dictionary, has been developed and applied to JET neutron/gamma tomography. The method has been tested on JET experimental data and significant results are presented. The proposed method provides good reconstructions in terms of shapes and resolution.

  2. Gamma ray and neutron shielding properties of some concrete materials

    International Nuclear Information System (INIS)

    Yilmaz, E.; Baltas, H.; Kiris, E.; Ustabas, I.; Cevik, U.; El-Khayatt, A.M.

    2011-01-01

    Highlights: → This study sheds light on the shielding properties of gamma-rays and neutrons for some concrete samples. → The experimental mass attenuation coefficients values were compared with theoretical values obtained using WinXCom. → Moreover, neutron shielding has been treated in terms of macroscopic removal cross-section (Σ R , cm -1 ) concept. → The NXcom program was employed to calculate the attenuation coefficients values of neutrons. → These values showed a change with energy and composition of the concrete samples. - Abstract: Shielding of gamma-rays and neutrons by 12 concrete samples with and without mineral additives has been studied. The total mass attenuation and linear attenuation coefficients, half-value thicknesses, effective atomic numbers, effective electron densities and atomic cross-sections at photons energies of 59.5 and 661 keV have been measured and calculated. The measured and calculated values were compared and a reasonable agreement has been observed. Also the recorded values showed a change with energy and composition of the concrete samples. In addition, neutron shielding has been treated in terms of macroscopic removal cross-section (Σ R , cm -1 ) concept. The WinXCom and NXcom programs were employed to calculate the attenuation coefficients of gamma-rays and neutrons, respectively.

  3. Gamma-ray measurements at the WNR white neutron source

    International Nuclear Information System (INIS)

    Nelson, R.O.; Wender, S.A.; Mayo, D.R.

    1994-01-01

    Photon production data have been acquired in the incident neutron energy range, 1 n γ 56 Fe, and 207,208 Pb. These data are useful both for testing nuclear reaction models at intermediate energies and for numerous applied purposes. BGO detectors do not have the good energy resolution of Ge detectors, but have much greater detection efficiency for gamma rays with energies greater than a few MeV. We have used an array of 5 BGO detectors to measure cross sections and angular distributions for photon production from C and N. A large, well-shielded BGO detector has been used to measure fast neutron capture in the giant resonance region with a maximum gamma-ray energy of 52 MeV. We present results of our study of the isovector giant quadrupole resonance in 41 Ca via these capture measurements. Recent measurements of inclusive photon spectra from our neutron proton Bremsstrahlung experiment have been made using a gamma-ray telescope to detect gamma-rays in the energy range, 40 γ < 300 MeV. This detector is briefly described. The advantages and disadvantages of these detector systems are discussed using examples from our measurements. The status of current measurements is presented

  4. Neutron stimulated emission computed tomography: Background corrections

    International Nuclear Information System (INIS)

    Floyd, Carey E.; Sharma, Amy C.; Bender, Janelle E.; Kapadia, Anuj J.; Xia, Jessie Q.; Harrawood, Brian P.; Tourassi, Georgia D.; Lo, Joseph Y.; Kiser, Matthew R.; Crowell, Alexander S.; Pedroni, Ronald S.; Macri, Robert A.; Tajima, Shigeyuki; Howell, Calvin R.

    2007-01-01

    Neutron stimulated emission computed tomography (NSECT) is an imaging technique that provides an in-vivo tomographic spectroscopic image of the distribution of elements in a body. To achieve this, a neutron beam illuminates the body. Nuclei in the body along the path of the beam are stimulated by inelastic scattering of the neutrons in the beam and emit characteristic gamma photons whose unique energy identifies the element. The emitted gammas are collected in a spectrometer and form a projection intensity for each spectral line at the projection orientation of the neutron beam. Rotating and translating either the body or the beam will allow a tomographic projection set to be acquired. Images are reconstructed to represent the spatial distribution of elements in the body. Critical to this process is the appropriate removal of background gamma events from the spectrum. Here we demonstrate the equivalence of two background correction techniques and discuss the appropriate application of each

  5. Whole Core Thermal-Hydraulic Design of a Sodium Cooled Fast Reactor Considering the Gamma Energy Transport

    International Nuclear Information System (INIS)

    Choi, Sun Rock; Back, Min Ho; Park, Won Seok; Kim, Sang Ji

    2012-01-01

    Since a fuel cladding failure is the most important parameter in a core thermal-hydraulic design, the conceptual design stage only involves fuel assemblies. However, although non-fuel assemblies such as control rod, reflector, and B4C generate a relatively smaller thermal power compared to fuel assemblies, they also require independent flow allocation to properly cool down each assembly. The thermal power in non-fuel assemblies is produced from both neutron and gamma energy, and thus the core thermal-hydraulic design including non-fuel assemblies should consider an energy redistribution by the gamma energy transport. To design non-fuel assemblies, the design-limiting parameters should be determined considering the thermal failure modes. While fuel assemblies set a limiting factor with cladding creep temperature to prevent a fission product ejection from the fuel rods, non-fuel assemblies restrict their outlet temperature to minimize thermally induced stress on the upper internal structure (UIS). This work employs a heat generation distribution reflecting both neutron and gamma transport. The whole core thermal-hydraulic design including fuel and non-fuel assemblies is then conducted using the SLTHEN (Steady-State LMR Thermal-Hydraulic Analysis Code Based on ENERGY Model) code. The other procedures follow from the previous conceptual design

  6. Study of associated gamma from niobium under 14. 9 MeV neutron bombardments

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Hongyu; Yan Yiming; Fan Guoying; Lan Liqiac; Sun Suxu; Wang Qi; Hua Ming; Han Chongzhen; Liu Shuzhenn; Rong Yaning; and others

    1989-02-01

    The gamma ray spectra from niobium under 14.9 MeV neutron bombardments were measured by means of a pulsed /ital T/(/ital d/, /ital n/)/sup 4/He neutron source, associated particle method, Ge(Li) detector and time-of-flight technique at 7 angles between 30/degree/ and 140/degree/. 79 gamma lines were determined by a high resolution gamma spectrum analysis program, and reaction types and transition levels of 62 lines were roughly assigned. There were 40 ones of 79 lines, which were first found in reactions induced by neutrons. The differential cross sections of every gamma line at 7 angles were determined. It is shown that associated gamma ray emissions from this reaction are basically isotropic.

  7. Inter-pulse high-resolution gamma-ray spectra using a 14 MeV pulsed neutron generator

    Science.gov (United States)

    Evans, L.G.; Trombka, J.I.; Jensen, D.H.; Stephenson, W.A.; Hoover, R.A.; Mikesell, J.L.; Tanner, A.B.; Senftle, F.E.

    1984-01-01

    A neutron generator pulsed at 100 s-1 was suspended in an artificial borehole containing a 7.7 metric ton mixture of sand, aragonite, magnetite, sulfur, and salt. Two Ge(HP) gamma-ray detectors were used: one in a borehole sonde, and one at the outside wall of the sample tank opposite the neutron generator target. Gamma-ray spectra were collected by the outside detector during each of 10 discrete time windows during the 10 ms period following the onset of gamma-ray build-up after each neutron burst. The sample was measured first when dry and then when saturated with water. In the dry sample, gamma rays due to inelastic neutron scattering, neutron capture, and decay were counted during the first (150 ??s) time window. Subsequently only capture and decay gamma rays were observed. In the wet sample, only neutron capture and decay gamma rays were observed. Neutron capture gamma rays dominated the spectrum during the period from 150 to 400 ??s after the neutron burst in both samples, but decreased with time much more rapidly in the wet sample. A signal-to-noise-ratio (S/N) analysis indicates that optimum conditions for neutron capture analysis occurred in the 350-800 ??s window. A poor S/N in the first 100-150 ??s is due to a large background continuum during the first time interval. Time gating can be used to enhance gamma-ray spectra, depending on the nuclides in the target material and the reactions needed to produce them, and should improve the sensitivity of in situ well logging. ?? 1984.

  8. Design of a versatile detector for the detection of charged particles, neutrons and gamma rays. Neutron interaction with the matter

    International Nuclear Information System (INIS)

    Perez P, J.J.

    1991-01-01

    The Fostron detector detects charged particles, neutrons and gamma rays with a reasonable discrimination power. Because the typical detectors for neutrons present a great uncertainty in the detection, this work was focused mainly to the neutron detection in presence of gamma radiation. Also there are mentioned the advantages and disadvantages of the Fostron detector

  9. Neutron and gamma characterization within the FFTF reactor cavity

    International Nuclear Information System (INIS)

    Bunch, W.L.; Carter, L.L.; Moore, F.S.; Werner, E.J.; Wilcox, A.D.; Wood, M.R.

    1980-08-01

    Neutron and gamma ray measurements were made within the reactor cavity of the Fast Flux Test Facility (FFTF) to establish the operating characteristics of the Ex-Vessel Flux Monitoring (EVFM) system as a function of reactor power level. A significant effort was made to obtain absolute flux values in order that the measurements could be compared directly with shield design calculations. Good agreement was achieved for neutrons and for both the prompt and delayed components of the gamma ray field. 8 figures, 3 tables

  10. Pharmacokinetics and whole body distribution of elastase derived angiostatin (k1-3) in rats

    NARCIS (Netherlands)

    Molema, Grietje; van Veen-Hof, Ingrid; van Loenen - Weemaes, Anne-miek; Proost, Johannes; de Leij, Lou F.M.H.; Meijer, Dirk K.F.

    2001-01-01

    In the current study, we determined short-term pharmacokinetics and whole body distribution of elastase derived angiostatin [angiostatin((k1-3))] in rats after i.v. injection of radiolabelled protein. Since In gamma-camera studies, no tumor specific angiostatin((k1-3)) accumulation was observed,

  11. Sensitivity Analysis of Cf-252 (sf) Neutron and Gamma Observables in CGMF

    Energy Technology Data Exchange (ETDEWEB)

    Carter, Austin Lewis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Talou, Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stetcu, Ionel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kiedrowski, Brian Christopher [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jaffke, Patrick John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-12-06

    CGMF is a Monte Carlo code that simulates the decay of primary fission fragments by emission of neutrons and gamma rays, according to the Hauser-Feshbach equations. As the CGMF code was recently integrated into the MCNP6.2 transport code, great emphasis has been placed on providing optimal parameters to CGMF such that many different observables are accurately represented. Of these observables, the prompt neutron spectrum, prompt neutron multiplicity, prompt gamma spectrum, and prompt gamma multiplicity are crucial for accurate transport simulations of criticality and nonproliferation applications. This contribution to the ongoing efforts to improve CGMF presents a study of the sensitivity of various neutron and gamma observables to several input parameters for Californium-252 spontaneous fission. Among the most influential parameters are those that affect the input yield distributions in fragment mass and total kinetic energy (TKE). A new scheme for representing Y(A,TKE) was implemented in CGMF using three fission modes, S1, S2 and SL. The sensitivity profiles were calculated for 17 total parameters, which show that the neutron multiplicity distribution is strongly affected by the TKE distribution of the fragments. The total excitation energy (TXE) of the fragments is shared according to a parameter RT, which is defined as the ratio of the light to heavy initial temperatures. The sensitivity profile of the neutron multiplicity shows a second order effect of RT on the mean neutron multiplicity. A final sensitivity profile was produced for the parameter alpha, which affects the spin of the fragments. Higher values of alpha lead to higher fragment spins, which inhibit the emission of neutrons. Understanding the sensitivity of the prompt neutron and gamma observables to the many CGMF input parameters provides a platform for the optimization of these parameters.

  12. EJ-309 pulse shape discrimination performance with a high gamma-ray-to-neutron ratio and low threshold

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, A.C., E-mail: Alexis.C.Kaplan@gmail.com [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd., Ann Arbor, MI 48104 (United States); Nuclear Engineering and Nonproliferation Division, Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Flaska, M.; Enqvist, A.; Dolan, J.L.; Pozzi, S.A. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd., Ann Arbor, MI 48104 (United States)

    2013-11-21

    Measuring neutrons in the presence of high gamma-ray fluence is a challenge with multi-particle detectors. Organic liquid scintillators such as the EJ-309 are capable of accurate pulse-shape discrimination (PSD) but the chance for particle misclassification is not negligible for some applications. By varying the distance from an EJ-309 scintillator to a strong-gamma-ray source and keeping a weak-neutron source at a fixed position, various gamma-to-neutron ratios can be measured and PSD performance can be quantified. Comparing neutron pulse-height distributions allows for pulse-height specific PSD evaluation, and quantification and visualization of deviation from {sup 252}Cf alone. Even with the addition of the misclassified gamma-rays, the PSD is effective in separating particles so that neutron count rate can be predicted with less than 10% error up to a gamma-to-neutron ratio of almost 650. For applications which can afford a reduction in neutron detection efficiency, PSD can be sufficiently effective in discriminating particles to measure a weak neutron source in a high gamma-ray background. -- Highlights: •We measure neutrons in a high photon background with EJ-309 liquid scintillators. •A low threshold is used to test the limits of particle discrimination. •A weak neutron signal is detectable with a gamma/neutron ratio as high as 770. •Photon pileup most commonly adds to error in classification of neutrons. •Neutron count rates are within 10% of expected rate under high gamma background.

  13. EJ-309 pulse shape discrimination performance with a high gamma-ray-to-neutron ratio and low threshold

    International Nuclear Information System (INIS)

    Kaplan, A.C.; Flaska, M.; Enqvist, A.; Dolan, J.L.; Pozzi, S.A.

    2013-01-01

    Measuring neutrons in the presence of high gamma-ray fluence is a challenge with multi-particle detectors. Organic liquid scintillators such as the EJ-309 are capable of accurate pulse-shape discrimination (PSD) but the chance for particle misclassification is not negligible for some applications. By varying the distance from an EJ-309 scintillator to a strong-gamma-ray source and keeping a weak-neutron source at a fixed position, various gamma-to-neutron ratios can be measured and PSD performance can be quantified. Comparing neutron pulse-height distributions allows for pulse-height specific PSD evaluation, and quantification and visualization of deviation from 252 Cf alone. Even with the addition of the misclassified gamma-rays, the PSD is effective in separating particles so that neutron count rate can be predicted with less than 10% error up to a gamma-to-neutron ratio of almost 650. For applications which can afford a reduction in neutron detection efficiency, PSD can be sufficiently effective in discriminating particles to measure a weak neutron source in a high gamma-ray background. -- Highlights: •We measure neutrons in a high photon background with EJ-309 liquid scintillators. •A low threshold is used to test the limits of particle discrimination. •A weak neutron signal is detectable with a gamma/neutron ratio as high as 770. •Photon pileup most commonly adds to error in classification of neutrons. •Neutron count rates are within 10% of expected rate under high gamma background

  14. Recognition of internal structure of unknown objects with simultaneous neutron and gamma radiography

    International Nuclear Information System (INIS)

    Moghadam, K.K.; Nasseri, M.M.

    2004-01-01

    Generally speaking in customary industrial and medical radiography, there is no tendency to reveal the nature of the samples. Ordinarily, the main objective of taking a radiograph is to show the position and dimension of unknown parts, inside the test object and to determine cracks, defects, etc. Whereas in radiography many important factors such as material cross-sections and build-up factors are also involved. In this paper, by using both neutron and gamma radiography techniques, some mathematical relations were successfully generated, in order to calculate the neutron and gamma total macroscopic cross-sections of some unknown elements in the presence of the other elements. For this work, some test pieces were defined and made of lead, silver, copper, Nickel, tin, graphite and polyethylene. The neutron radiography facility at Tehran Research Reactor (TRR) was used as mixed neutron and gamma radiography source (Proceedings of the Second World Conference on Neutron Radiography, Paris, France, pp. 25-32). On testing of a correction of the above-mentioned generated relations, a new technique of simultaneous neutron and gamma radiography was also investigated

  15. Hanford whole body counting manual

    International Nuclear Information System (INIS)

    Palmer, H.E.; Brim, C.P.; Rieksts, G.A.; Rhoads, M.C.

    1987-05-01

    This document, a reprint of the Whole Body Counting Manual, was compiled to train personnel, document operation procedures, and outline quality assurance procedures. The current manual contains information on: the location, availability, and scope of services of Hanford's whole body counting facilities; the administrative aspect of the whole body counting operation; Hanford's whole body counting facilities; the step-by-step procedure involved in the different types of in vivo measurements; the detectors, preamplifiers and amplifiers, and spectroscopy equipment; the quality assurance aspect of equipment calibration and recordkeeping; data processing, record storage, results verification, report preparation, count summaries, and unit cost accounting; and the topics of minimum detectable amount and measurement accuracy and precision. 12 refs., 13 tabs

  16. Effect of high gamma background on neutron sensitivity of fission detectors

    International Nuclear Information System (INIS)

    Balagi, V.; Prasad, K.R.; Kataria, S.K.

    2004-01-01

    Tests were performed on two parallel plate and two cylindrical fission detectors in pulse and dc mode. The effect of gamma background on neutron sensitivity was studied in thermal neutron flux from 30 nv to 60 nv over which gamma field intensity ranging from 230 kR/h to 3.7 MR/h was superposed. In the case of one of the parallel plate detectors the fall in neutron sensitivity was observed to be 3.7% at 1 MR/h and negligible below 1 MR/h. In the case of one of the cylindrical counters the fall in neutron sensitivity was negligible below 500 kR/h and 37% at 1 MR/h. The data was used to derive the design parameters for a wide range fission detector to be procured for PFBR instrumentation for operation at 600 degC and gamma background of 1 MR/h. (author)

  17. Calibration of the A.E.E. Winfrith whole body monitor equipment with sodium-24 solution in a polythene man-phantom

    International Nuclear Information System (INIS)

    Peabody, C.O.; Speight, R.G.; Passant, F.H.

    1964-04-01

    Results are presented for the sensitivity of the existing Winfrith Whole Body Monitor equipment when used for measurement of sodium-24 activity in solution in a polythene man-phantom. The relationship is discussed between these results and those expected for the sodium-24 produced in a human body by accidental neutron irradiation. Estimates are made of the additional contribution of chlorine-38 activity at various times after whole body irradiation. (author)

  18. Attenuation of neutrons and gamma-rays in homogeneous and multilayered shields

    International Nuclear Information System (INIS)

    Abdo, A.E.; Megahid, R.M.

    1997-01-01

    Measurements were carried-out to compare the attenuation properties of homogeneous shields and shields of two layers and three layers for fast neutrons and total gamma-rays. These were performed by measuring the fast neutron and total gamma-ray spectra behind homogeneous shields of magnetite-limonite, ilmenite-ilmenite and magnetite-magnetite concretes. The two layers assembly consists of iron and one of the above mentioned concretes, while the three layers shield consists of water, iron and one of the previously mentioned concretes. All measurements were carried-out using a neutron-gamma spectrometer with stilbene scintillator coupled to a fast photo multi player tube. Separation between pulses of recoil protons and recoil electrons was achieved by a pulse shape discrimination technique. 3 tabs., 10 figs., 13 refs

  19. Performance of neutron and gamma personnel dosimetry in mixed radiation fields

    International Nuclear Information System (INIS)

    Swaja, R.E.; Sims, C.S.

    1981-01-01

    From 1974 to 1980, six personnel dosimetry intercomparison studies (PDIS) were conducted at the Oak Ridge National Laboratory (ORNL) to evaluate the performance of personnel dosimeters in a variety of neutron and gamma fields produced by operating the Health Physics Research Reactor (HPRR) in the steady state mode with and without spectral modifying shields. A total of 58 different organizations participated in these studies which produced approximately 2000 measurements of neutron and gamma dose equivalents on anthropomorphic phantoms for five different reactor spectra. Based on these data, the relative performance of three basic types of neutron dosimeters [nuclear emulsion film, thermoluminescent (TLD), and track-etch] and two basic types of gamma dosimeters (film and TLD) in mixed radiation fields was assessed

  20. 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

  1. Whole-body counting 1990

    International Nuclear Information System (INIS)

    Strand, P.; Selnaes, T.D.

    1990-01-01

    In order to determine the doses from radiocesium in foods after the Chernobyl accident, four groups were chosen in 1987. Two groups, presumed to have a large consumption of food items with a high radiocesium content, were selected. These were Lapp reindeer breeders from central parts of Norway, and hunters a.o. from the municipality of Oeystre Slidre. Two other groups were randomly selected, one from the municipality of Sel, and one from Oslo. The persons in these two groups were presumed to have an average diet. The fall-out in Sel was fairly large (100 kBq/m 2 ), whereas in Oslo the fall-out level was low (2 kBq/m 2 ). The persons in each group were monitored once a year with whole-body counters, and in connection with these countings dietary surveys were preformed. In 1990 the Sel-group and the Lapps in central parts of Norway were followed. Average whole-body activity in each group is compared to earlier years's results, and an average yearly effective dose equivalent is computed. The Sel-group has an average whole-body activity of 2800 Bq for men, and 690 Bq for women. Compared to earlier years, there is a steady but slow decrease in whole-body activities. Yearly dose is calculated to 0.06 mSv for 1990. The Lapps in central parts of Norway have an average whole-body content of 23800 Bq for men and 13600 Bq for women. This results in an average yearly dose of 0.9 mSv for the individuals in the group. Compared to earlier years, the Lapp group show a decrease in whole-body contents since 1988. This decrease is larger among men than women. 5 refs., 8 figs., 6 tabs

  2. Measurements of neutron and gamma ray streaming through a duct, (2), (3)

    International Nuclear Information System (INIS)

    Hashikura, Hiroyuki; Fukumoto, Hideshi; Akiyama, Masatsugu; Oka, Yoshiaki; An, Shigehiro

    1982-03-01

    Measurements of neutron and gamma ray streaming through a duct measurements of and a cavity in concrete shields were measured in the fast neutron source reactor YAYOI of the University of Tokyo. The neutron spectra measured by a NE213 scintillator and proton recoil counters were compared with the calculations using Monte Carlo code, MORSE-CG. The agreements between the experiments and the calculations were generally satisfactory. The attenuations of neutron and gamma ray in the cavity and the duct were studied in the three experimental configurations. (author)

  3. The estimation of total body fat by inelastic neutron scattering - a geometrical feasibility study

    International Nuclear Information System (INIS)

    Lizos, F.; Kotzasarlidoou, M.; Makridou, A.; Giannopoulou, K.

    2012-01-01

    A rough quantitative representation of the basic elements in a human body is shown. It deals with a hypothetical, normal adult weighting 70 kg. It is possible to measure two basic quantities, the FFM, standing for Fat Free Mass and the FM, standing for Fat Mass. The present simulation deals with the most important aspect of the estimation of storage fat in the human body and in order to accomplish such a task, it is considered a representation of the human body, containing a uniform distribution of triacylglycerols, in a shape of cylindrical phantom. The whole process is analyzed and simulated by a geometrical model and with the aid of a computer program which takes into consideration the different attenuation for neutrons and photons, the amount of gamma radiation reaching the detector is also calculated. The net result is the determination of sensitivity for a particular set-up and by relating the out coming data to the amount of carbon; the quantity of fat is estimated. In addition, the non-uniformity is calculated, from the computer programs expressing the consistency of the system. In order to determine the storage fat, a simulation model that will enable to represent the detection of the carbon atoms in triacylglycerols was built

  4. A gamma/neutron-discriminating, Cooled, Optically Stimulated Luminescence (COSL) dosemeter

    International Nuclear Information System (INIS)

    Eschbach, P.A.; Miller, S.D.

    1992-07-01

    The Cooled Optically Stimulated Luminescence (COSL) of CaF 2 :Mn (grain sizes from 0.1 to 100 microns) powder embedded in a hydrogenous matrix is reported as a function of fast-neutron dose. When all the CaF 2 :Mn grains are interrogated at once, the COSL plastic dosemeters have a minimum detectable limit of 1 cSv fast neutrons; the gamma component from the bare 252 cf exposure was determined with a separate dosemeter. We report here on a proton-recoil-based dosemeter that generates pulse height spectra, much like the scintillator of Hornyak, (2) to provide information on both the neutron and gamma dose

  5. Production of low energy gamma rays by neutron interactions with fluorine for incident neutron energies between 0.1 and 20 MeV

    International Nuclear Information System (INIS)

    Morgan, G.L.; Dickens, J.K.

    1975-06-01

    Differential cross sections for the production of low-energy gamma rays (less than 240 keV) by neutron interactions in fluorine have been measured for neutron energies between 0.1 and 20 MeV. The Oak Ridge Electron Linear Accelerator was used as the neutron source. Gamma rays were detected at 92 0 using an intrinsic germanium detector. Incident neutron energies were determined by time-of-flight techniques. Tables are presented for the production cross sections of three gamma rays having energies of 96, 110, and 197 keV. (14 figures, 3 tables) (U.S.)

  6. Discrimination of neutrons and gamma quanta with the aid of their power density spectra

    International Nuclear Information System (INIS)

    Buchmueller, R.

    1977-01-01

    The paper introduces a method of using only one fission chamber to discriminate the neutron flux against the gamma flux. The gamma chamber current may be several orders of magnitude higher than the neutron chamber current. In specially dimensioned fission chambers the neutrons and gamma quanta are made to generate different current pulses. Discrimination becomes possible by recording the power density spectrum of the mixture of pulses over a broad frequency range ( [de

  7. Gamma-ray production cross sections for MeV neutrons

    International Nuclear Information System (INIS)

    Kitazawa, Hideo; Harima, Yoshiko; Yamakoshi, Hisao; Sano, Yuji; Kobayashi, Tsuguyuki.

    1979-01-01

    Gamma-ray production cross section and spectra for 1- to 20-MeV neutrons were theoretically obtained, which were requested for heating calculations, for shielding design calculations, and for material damage estimates. Calculations were carried out for Al, Si, Ca, Fe, Ni, Cu, Nb, Ta, Au, and Pb, using a spin-dependent evaporation model without the parity conservation and including the dipole and quardupole gamma-ray transitions. The results were compared with the experimental data measured in ORNL to confirm the availability of this model in applications. In addition, the effects on the gamma-ray production cross section of the optical potential, level density, yrast level, and radiation width were investigated in detail. The conclusions are: 1) the use of the optical potential which gives the correct total reaction cross section is essential to gamma-ray production calculations, 2) the gamma-ray production cross section is not so sensitive to the choice of level density parameters, 3) the inclusion of yrast levels is necessary in dealing with the competition of the neutron and gamma-ray emissions from highly excited states, and 4) the Brink-Axel type's radiation width is unsuitable to be applied to radiative capture processes. (author)

  8. Optimization of electret ionization chambers for dosimetry in mixed neutron-gamma fields

    International Nuclear Information System (INIS)

    Doerschel, B.; Pretzsch, G.

    1984-01-01

    The properties of combination dosemeters consisting of two air-filled electret ionization chambers in mixed neutron-gamma fields have been investigated. The first chamber, polyethylene-walled, is sensitive to neutrons and gamma rays, the second, having walls of teflon, is sensitive to gamma rays only. The properties of the dosemeters are determined by the resulting errors and the measuring range. As both properties depend on the dimensions of the electret ionization chambers they have been taken into account in optimizing the dimensions. The results show that with the use of the dosemeters the effective dose equivalent in mixed neutron-gamma fields can be determined nearly independently of the spectra. The lower detection limit is less than 1 mSv and the maximum uncertainty of dose measurements about 12%. (author)

  9. Hanford whole body counting manual

    International Nuclear Information System (INIS)

    Palmer, H.E.; Rieksts, G.A.; Lynch, T.P.

    1990-06-01

    This document describes the Hanford Whole Body Counting Program as it is administered by Pacific Northwest Laboratory (PNL) in support of the US Department of Energy--Richland Operations Office (DOE-RL) and its Hanford contractors. Program services include providing in vivo measurements of internally deposited radioactivity in Hanford employees (or visitors). Specific chapters of this manual deal with the following subjects: program operational charter, authority, administration, and practices, including interpreting applicable DOE Orders, regulations, and guidance into criteria for in vivo measurement frequency, etc., for the plant-wide whole body counting services; state-of-the-art facilities and equipment used to provide the best in vivo measurement results possible for the approximately 11,000 measurements made annually; procedures for performing the various in vivo measurements at the Whole Body Counter (WBC) and related facilities including whole body counts; operation and maintenance of counting equipment, quality assurance provisions of the program, WBC data processing functions, statistical aspects of in vivo measurements, and whole body counting records and associated guidance documents. 16 refs., 48 figs., 22 tabs

  10. Time Evolving Fission Chain Theory and Fast Neutron and Gamma-Ray Counting Distributions

    International Nuclear Information System (INIS)

    Kim, K. S.; Nakae, L. F.; Prasad, M. K.; Snyderman, N. J.; Verbeke, J. M.

    2015-01-01

    Here, we solve a simple theoretical model of time evolving fission chains due to Feynman that generalizes and asymptotically approaches the point model theory. The point model theory has been used to analyze thermal neutron counting data. This extension of the theory underlies fast counting data for both neutrons and gamma rays from metal systems. Fast neutron and gamma-ray counting is now possible using liquid scintillator arrays with nanosecond time resolution. For individual fission chains, the differential equations describing three correlated probability distributions are solved: the time-dependent internal neutron population, accumulation of fissions in time, and accumulation of leaked neutrons in time. Explicit analytic formulas are given for correlated moments of the time evolving chain populations. The equations for random time gate fast neutron and gamma-ray counting distributions, due to randomly initiated chains, are presented. Correlated moment equations are given for both random time gate and triggered time gate counting. There are explicit formulas for all correlated moments are given up to triple order, for all combinations of correlated fast neutrons and gamma rays. The nonlinear differential equations for probabilities for time dependent fission chain populations have a remarkably simple Monte Carlo realization. A Monte Carlo code was developed for this theory and is shown to statistically realize the solutions to the fission chain theory probability distributions. Combined with random initiation of chains and detection of external quanta, the Monte Carlo code generates time tagged data for neutron and gamma-ray counting and from these data the counting distributions.

  11. Attenuation of Reactor Gamma Radiation and Fast Neutrons Through Large Single-Crystal Materials

    International Nuclear Information System (INIS)

    Adib, M.

    2009-01-01

    A generalized formula is given which, for neutron energies in the range 10-4< E< 10 eV and gamma rays with average energy 2 MeV , permits calculation of the transmission properties of several single crystal materials important for neutron scattering instrumentation. A computer program Filter was developed which permits the calculation of attenuation of gamma radiation, nuclear capture, thermal diffuse and Bragg-scattering cross-sections as a function of materials constants, temperature and neutron energy. The applicability of the deduced formula along with the code checked from the obtained agreement between the calculated and experimental neutron transmission through various single-crystals A feasibility study for use of Si, Ge, Pb, Bi and sapphire is detailed in terms of optimum crystal thickness, mosaic spread and cutting plane for efficient transmission of thermal reactor neutrons and for rejection of the accompanying fast neutrons and gamma rays.

  12. Whole-body computed tomography

    International Nuclear Information System (INIS)

    Wegener, O.H.

    1992-01-01

    The vast literature on whole-body CT is presented in this bibliography which is published as a self-contained supplement to the monography entitled whole-body CT. For this documentation, the following journals have been scanned back to the year 1980: Journal of Computer Assisted Tomography (JCAT), Fortschritte auf dem Gebiet der Roentgenstrahlen (RoeFo), Radiology, American Journal of Roentgenology (AJR), Der Radiologe, Neuroradiology, and American Journal of Neuroradiology (AJNR). The supplement includes keyword indexes that can be searched for terms indicating body organs, body regions, or certain lesions. The author index offers an additional access to the publication wanted. (orig./MG) [de

  13. Design of a versatile detector for the detection of charged particles, neutrons and gamma rays. Neutron interaction with the matter; Diseno de un detector versatil para la deteccion de particulas cargadas, neutrones y rayos gamma. Interaccion neutronica con la materia

    Energy Technology Data Exchange (ETDEWEB)

    Perez P, J J [Comision Nacional de Seguridad Nuclear y Salvaguardias, Mexico, D.F. (Mexico)

    1991-07-01

    The Fostron detector detects charged particles, neutrons and gamma rays with a reasonable discrimination power. Because the typical detectors for neutrons present a great uncertainty in the detection, this work was focused mainly to the neutron detection in presence of gamma radiation. Also there are mentioned the advantages and disadvantages of the Fostron detector.

  14. Differential effects of whole-body {gamma}-irradiation on antinociception induced by morphine and {beta}-endorphin administered intracerebroventricularly in the mouse

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.K. [Korea Atomic Energy Research Inst., Taejon (Korea, Republic of); Chung, K.M.; Park, T.W.

    2000-05-01

    Two separate lines of evidence suggested the present study. First, intracerebroventricularly (i.c.v.) administered morphine (a {mu}-opioid receptor agonist) and {beta}-endorphin (an {epsilon}-opioid receptor agonist) produce antinociception by activating different descending pain inhibitory systems. Second, {gamma}-irradiation attenuates the acute antinociceptive action of i.c.v. injected morphine, but not DPLPE (a {delta}-opioid receptor agonist), in mice. These findings prompted us to investigate the effect of {gamma}-irradiation on the antinociception produced by i.c.v. injected morphine and {beta}-endorphin in male ICR mice. In one group, mice were exposed to whole-body irradiation at a dose of 5 Gy from a {sup 60}Co {gamma}-source and the antinociceptive effects were tested 5, 30, 60,90 and 180 min after irradiation using the 1% acetic acid-induced writhing test (10 ml/kg). The antinociceptive effect was produced time-dependently and reached its maximum at 90 min after irradiation. Thus, time was fixed in the following studies. In another group, mice were irradiated with 5 Gy and tested 90 minutes later for antinociception produced by i.c.v. administration of morphine (50 and 100 ng/mouse) or {beta}-endorphin (31 ng/mouse). Irradiation significantly potentiated the antinociception produced by {beta}-endorphin. However, the antinociception produced by morphine was not affected by irradiation. These results demonstrate a differential sensitivity of {mu}- and {epsilon}-opioid receptors to {gamma}-irradiation, in addition, support the hypothesis that morphine and {beta}-endorphin administered supraspinally produce antinociception by different neuronal mechanisms. (author)

  15. Whole-body profile scanner for in vivo quantitative activity measurement

    International Nuclear Information System (INIS)

    Bergmann, H.

    1978-01-01

    A whole-body profile scanner has been developed by fitting parallel slit collimators to a shadow shield whole-body counter. Sensitivity, uniformity and resolution measurements were performed using a number of different counting conditions. It is shown that improved accuracy of activity measurements is obtained by using a wide window counting technique for low and medium energy gamma emitters (99m Tc, 131 I), whereas a photopeak window should be used for high energy gamma emitters (47 Ca). Due to the finite spatial resolution of the system a systematic error in evaluating regional activities from the counting rate profile occurs which is characterized by a spatial spillover factor. The spatial spillover factor is measured and is subsequently used to calculate the error on basis of a simple model. It is shown that only small errors are caused by spatial spillover when the length of a region is at least three times the full width half maximum of the point spread function. Applying the above mentioned simple rules it is concluded that profile scanning is a sensitive and accurate technique for activity measurements in vivo. Two examples of clinical applications (measurement of bone accretion rates of calcium and Tc-pyrophosphate, regional radioiodine retention in patients with thyroid carcinoma) and a review of the papers on profile scanning demonstrate the types of investigations in which profile scanning is superior to alternative techniques. (author)

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

    Science.gov (United States)

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

    1972-01-01

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

  17. Cold neutron prompt gamma activation analysis at NIST; A progress report

    Energy Technology Data Exchange (ETDEWEB)

    Paul, R L; Lindstrom, R M [National Inst. of Standards and Technology, Gaithersburg, MD (United States). Div. of Inorganic Analytical Research; Vincent, D H [Michigan Univ., Ann Arbor, MI (United States). Dept. of Nuclear Engineering

    1994-05-01

    An instrument for prompt gamma-ray activation analysis is now in operation at the NIST Cold Neutron Research Facility (CNRF). The cold neutron beam is relatively free of contamination by fast neutrons and reactor gamma rays, and the neutron fluence rate is 1.5 x 10 [sup 8] cm [sup -2] x s [sup -1] (thermal equivalent). As a result of a compact target-detector geometry the sensitivity is better by a factor of as much as seven than that obtained with an existing thermal instrument, and hydrogen background is a factor of 50 lower. This instrument was applied to multielement analysis of the Allende meteorite and other materials. (author) 14 refs.; 2 figs.; 1 tab.

  18. Effect of gamma and neutron irradiation on the mechanical properties of Spectralon™ porous PTFE

    Energy Technology Data Exchange (ETDEWEB)

    Gourdin, William H., E-mail: gourdin1@llnl.gov [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA USA (United States); Datte, Philip; Jensen, Wayne; Khater, Hesham; Pearson, Mark [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA USA (United States); Girard, Sylvain [Laboratoire Hubert Curien − UMR CNRS 5516, 18 rue du Pr. Benoît Lauras, F-42000 Saint Etienne (France); Paillet, Philippe; Alozy, Eric [CEA, DAM, DIF, F-91297 Arpajon (France)

    2016-11-15

    Highlights: • The effects of neutrons and gammas on PTFE are equivalent for a given absorbed dose. • A neutron fluence of 10{sup 13} n/cm{sup 2} corresponds to a gamma dose of 200 Gy. • The dose-to-fluence conversion factor is approximately 5 × 10{sup 10} n/(cm{sup 2}-Gy). • Irradiation in a low-oxygen environment enhances loads and elongations. • Mechanical properties of PTFE will deteriorate at a neutron fluence of 10{sup 13} n/cm{sup 2}. - Abstract: We establish a correspondence between the mechanical properties (maximum load and failure elongation) of Spectralon™ porous PTFE irradiated with 14 MeV neutrons and 1.17 and 1.33 MeV gammas from a cobalt-60 source. From this correspondence we infer that the effects of neutrons and gammas on this material are approximately equivalent for a given absorbed dose.

  19. The progress of neutron induced prompt gamma analysis technique in 1988-2002

    International Nuclear Information System (INIS)

    Liu Yuren; Jing Shiwei

    2003-01-01

    The new development of the neutron induced prompt gamma-ray analysis (NIPGA) technology in 1988-2002 are described. The pulse fast-thermal neutron activation analysis method, which utilizes the inelastic reaction and capture reaction jointly is employed to measure the elemental content in the material more efficiently. The lifetime of the neutron generator is more than 10000 h and the capability of HPGe, TeZeCd and MCA (multi-channel analyser) reaches the high level. At the same time, Monte Carlo Library least-square method is used to solve the nonlinearity problem in the PGNAA (Prompt Gamma Neutron Activation Analysis)

  20. 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.

  1. Evaluation of an in vivo prompt gamma neutron activation facility for body composition studies in critically ill intensive care patients: results on 41 normals

    International Nuclear Information System (INIS)

    Beddoe, A.H.; Streat, S.J.; Hill, G.L.

    1984-01-01

    A programme of metabolic and nutritional research is being undertaken in critically ill patients requiring intensive care. Central to this research is the measurement of the three nutritionally important compartments of body composition, protein, fat, and water by a combination of tritium dilution and prompt gamma in vivo neutron activation analysis (IVNAA). In this paper a calibration technique is presented that enables absolute estimates of total body nitrogen (TBN) to be made using prompt gamma IVNAA in critically ill patients with gross abnormalities in body composition, especially in their state of hydration. This technique, which is independent of skinfold anthropometry and does not make a priori assumptions about the ratios of major body compartments, has been applied to 41 normal volunteers and the derived values for nitrogen compared with values obtained by applying three currently used calibration methods to the same experimental data. The empirical equations relate TBN in normal people to age, height, weight and sex. The mean ratios of experimental to predicted TBN (with SEMs) are 1.013 +/- 0.017 and 1.002 +/- 0.014, respectively. Mean values of the ratio of TBN to fat-free mass (0.0340 +/- 0.0004) and of total body water to fat-free mass (0.716 +/- 0.002) agree closely with values reported elsewhere for normals by a variety of techniques including chemical analysis. Finally, TBN results based on the four different calibration methods are presented for five surgical patients, demonstrating the importance of the calibration method on estimates of TBN in patients with abnormal body composition. It is concluded that this technique will provide accurate estimates of the total body content of protein, water, and fat in intensive care patients

  2. Neutron Activation Analysis with k0 standardisation

    International Nuclear Information System (INIS)

    Pomme, S.

    1998-01-01

    The objectives of the research are: (1) to develop and implement the k0 standardisation method for neutron activation analysis in close collaboration with scientific partners; (2) to exploit fully the inherent qualities of NAA such as accuracy, traceability, and multi-element offer complete services in health-physics measurements according to international quality standards, (2) to improve continuously these measurement techniques and to follow up international recommendations and legislation concerning the surveillance of workers; (3) to support and advise nuclear and non-nuclear industry on problems of radioactive contamination. Achievements in 1997 related to gamma spectrometry, whole-body counting, beta and alpha spectrometry, dosimetry, radon measurements, calibration, instrumentation, and neutron activation analysis are described

  3. Verification of Gamma-ray Sensitivity for BF3 Neutron Detection System

    International Nuclear Information System (INIS)

    Choi, Yu Sun; Cho, Jin Bok; Lyou, Seok Jean

    2016-01-01

    The BF3(Boron Tri-Fluorides) gas filled neutron detector(hereafter BF3 Detector) is commonly used for nuclear reactor’s startup channel due to its relatively high neutron efficiency and good discrimination against gamma-ray backgrounds. In order to measure how much this gamma-ray will affect on BF3 neutron detector performance in view of gamma noise discrimination, Multi-Channel Analyzer(MCA) is utilized for spectrum based signal analysis. The pre-test of BF3 Detector should be performed in an area where the ionization does not exceed 2.5 micro Gy/Hr(Ref.1). In this paper, the discrimination level (Voltage Unit) is verified by experimentally measurement if that discrimination level is acceptable within the criteria or not before installation. The maximum discrimination level, so called LLD, is determined by experimentally measurement. This BF3 Detector (LND20372) is insensitive under 540 micro Gy/Hr of gamma ray and 0.3V of LLD could cut off a background and gamma induced signal in a laboratory. MCA could be a convenient tool for spectrum analysis of signals that induced from gamma ray and a time saving tool rather than oscilloscope investigation due to its function to integrate all input signals at a sudden duration

  4. 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)

  5. Measurement of gamma-ray production cross sections in neutron-induced reactions for Al and Pb

    International Nuclear Information System (INIS)

    Pavlik, A.; Vonach, H.; Hitzenberger, H.

    1995-01-01

    The prompt gamma-radiation from the interaction of fast neutrons with aluminum and lead was measured using the white neutron beam of the WNR facility at the Los Alamos National Laboratory. The samples (Al and isotopically enriched 207 Pb and 208 Pb) were positioned at about 20 m or 41 m distance from the neutron production target. The spectra of the emitted gamma-rays were measured with a high-resolution HPGe detector. The incident neutron energy was determined by the time-of-flight method and the neutron fluence was measured with a U fission chamber. From the aluminum gamma-ray spectra excitation functions for prominent gamma-transitions in various residual nuclei (in the range from O to Al) were derived for neutron energies from 3 MeV to 400 MeV. For lead (n,xnγ) reactions were studied for neutron energies up to 200 MeV by analyzing prominent gamma-transitions in the residual nuclei 200,202,204,206,207,208 Pb. The experimental results were compared with nuclear model calculations using the code GNASH. A good overall agreement was obtained without special parameter adjustments

  6. Polycrystalline Materials as a Cold Neutron and Gamma Radiation Filter

    International Nuclear Information System (INIS)

    Habib, N.

    2009-01-01

    The total neutron cross-section of polycrystalline beryllium, graphite and iron has been calculated beyond their cut-off wavelength using a general formula. The computer Cold Filter code was developed in order to provide the required calculations. The code also permits the calculation of attenuation of reactor gamma radiation, The calculated neutron transmissions through polycrystalline Be graphite and iron at different temperatures were compared with the experimental data measured at the ETRR-1 reactor using two TOF spectrometers. An overall agreement is obtained between the formula fits and experimental data at different temperatures. A feasibility study is carried on using polycrystalline Be, graphite and iron an efficient filter for cold neutrons and gamma radiation.

  7. Simulation of neutrons and gamma pulse signal and research on the pulse shape discrimination technology

    International Nuclear Information System (INIS)

    Zuo Guangxia; He Bin; Xu Peng; Qiu Xiaolin; Ma Wenyan; Li Sufen

    2012-01-01

    In neutrons detection, it is important to discriminate the neutron signals from the gamma-ray background. In this article, simulation of neutrons and gamma pulse signals is developed based on the LabVIEW platform. Two digital algorithms of the charge comparison method and the pulse duration time method are realized using 10000 simulation signals. Experimental results show that neutron and gamma pulse signals can be discriminated by the two methods, and the pulse duration time method is better than the charge comparison method. (authors)

  8. Neutron-gamma discrimination based on pulse shape discrimination in a Ce:LiCaAlF{sub 6} scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Atsushi, E-mail: a-yamazaki@nucl.nagoya-u.ac.jp [Department of Materials, Physics and Energy Engineering, Graduate School of Engineering, Nagoya University (Japan); Watanabe, Kenichi; Uritani, Akira [Department of Materials, Physics and Energy Engineering, Graduate School of Engineering, Nagoya University (Japan); Iguchi, Tetsuo [Department of Quantum Engineering, Graduate School of Engineering, Nagoya University (Japan); Kawaguchi, Noriaki [Tokuyama Corporation (Japan); Yanagida, Takayuki; Fujimoto, Yutaka; Yokota, Yuui; Kamada, Kei [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University (Japan); Fukuda, Kentaro; Suyama, Toshihisa [Tokuyama Corporation (Japan); Yoshikawa, Akira [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University (Japan); New Industry Creation Hatchery Center (NICHe), Tohoku University (Japan)

    2011-10-01

    We demonstrate neutron-gamma discrimination based on a pulse shape discrimination method in a Ce:LiCAF scintillator. We have tried neutron-gamma discrimination using a difference in the pulse shape or the decay time of the scintillation light pulse. The decay time is converted into the rise time through an integrating circuit. A {sup 252}Cf enclosed in a polyethylene container is used as the source of thermal neutrons and prompt gamma-rays. Obvious separation of neutron and gamma-ray events is achieved using the information of the rise time of the scintillation light pulse. In the separated neutron spectrum, the gamma-ray events are effectively suppressed with little loss of neutron events. The pulse shape discrimination is confirmed to be useful to detect neutrons with the Ce:LiCAF scintillator under an intense high-energy gamma-ray condition.

  9. A dual neutron/gamma source for the Fissmat Inspection for Nuclear Detection (FIND) system.

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, Barney Lee (Sandia National Laboratories, Albuquerque, NM); King, Michael; Rossi, Paolo (Sandia National Laboratories, Albuquerque, NM); McDaniel, Floyd Del (Sandia National Laboratories, Albuquerque, NM); Morse, Daniel Henry; Antolak, Arlyn J.; Provencio, Paula Polyak (Sandia National Laboratories, Albuquerque, NM); Raber, Thomas N.

    2008-12-01

    Shielded special nuclear material (SNM) is very difficult to detect and new technologies are needed to clear alarms and verify the presence of SNM. High-energy photons and neutrons can be used to actively interrogate for heavily shielded SNM, such as highly enriched uranium (HEU), since neutrons can penetrate gamma-ray shielding and gamma-rays can penetrate neutron shielding. Both source particles then induce unique detectable signals from fission. In this LDRD, we explored a new type of interrogation source that uses low-energy proton- or deuteron-induced nuclear reactions to generate high fluxes of mono-energetic gammas or neutrons. Accelerator-based experiments, computational studies, and prototype source tests were performed to obtain a better understanding of (1) the flux requirements, (2) fission-induced signals, background, and interferences, and (3) operational performance of the source. The results of this research led to the development and testing of an axial-type gamma tube source and the design/construction of a high power coaxial-type gamma generator based on the {sup 11}B(p,{gamma}){sup 12}C nuclear reaction.

  10. 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.

  11. Production of gamma ray bursts from asymmetric core combustion of magnetized young neutron stars

    Science.gov (United States)

    de Gouveia dal Pino, E. M.; Lugones, G.; Horvath, J. E.; Ghezzi, C. R.

    2005-09-01

    Many works in the past have explored the idea that the conversion of hadronic matter into strange quark matter in neutron stars may be an energy source for GRBs (see references in Lugones et al. 2002, Lugones and Horvath 2003). These models addressed essentially spherically symmetric conversions of the whole neutron star rendering isotropic gamma emission. Accumulating observational evidence suggests that at least ''long'' GRBs are strongly asymmetric, jet-like outflows. The ''short'' burst subclass is not obviously asymmetric, and they may actually be spherically symmetric if the sources are close enough. A new potentially important feature recently recognized (Lugones et al. 2002) is that if a conversion to strange quark matter actually begins near the center of a neutron star, the presence of a magnetic field with intensity B ˜ 1013 G (see also Ghezi, de Gouveia Dal Pino & Horvath 2004) will originate a prompt collimated gamma emission, which may be observed as a short, beamed GRB after the recovery of a fraction of the neutrino energy via ν {barν} → e+e- → γγ. The calculations show that the neutrino luminosity is ˜ 1053 erg/sec and that the e+e- luminosity is about two orders of magnitude smaller ( tet{Lugones2002grb}). We find that 90 % of the e+e- pairs are injected inside small cylinders located just above the polar caps (with radius δ and height 0.4 R) in a timescale of τi ≃ 0.2 s almost independently of the initial temperature. This provides an interesting suitable explanation for the inner engine of short gamma ray bursts.

  12. Dose and dose rate effects of whole-body gamma-irradiation: II. Hematological variables and cytokines

    Science.gov (United States)

    Gridley, D. S.; Pecaut, M. J.; Miller, G. M.; Moyers, M. F.; Nelson, G. A.

    2001-01-01

    The goal of part II of this study was to evaluate the effects of gamma-radiation on circulating blood cells, functional characteristics of splenocytes, and cytokine expression after whole-body irradiation at varying total doses and at low- and high-dose-rates (LDR, HDR). Young adult C57BL/6 mice (n = 75) were irradiated with either 1 cGy/min or 80 cGy/min photons from a 60Co source to cumulative doses of 0.5, 1.5, and 3.0 Gy. The animals were euthanized at 4 days post-exposure for in vitro assays. Significant dose- (but not dose-rate-) dependent decreases were observed in erythrocyte and blood leukocyte counts, hemoglobin, hematocrit, lipopolysaccharide (LPS)-induced 3H-thymidine incorporation, and interleukin-2 (IL-2) secretion by activated spleen cells when compared to sham-irradiated controls (p factor-beta 1 (TGF-beta 1) and splenocyte secretion of tumor necrosis factor-alpha (TNF-alpha) were not affected by either the dose or dose rate of radiation. The data demonstrate that the responses of blood and spleen were largely dependent upon the total dose of radiation employed and that an 80-fold difference in the dose rate was not a significant factor in the great majority of measurements.

  13. Neutron gamma competition in fast fission

    International Nuclear Information System (INIS)

    Frehaut, J.

    1989-01-01

    In the present paper we analyse the data we have obtained on the distribution of the gamma-ray energy per fission, as well as on the average energy E-barγ released per fission for the neutron induced fission of several isotopes, in the energy range up to 15 MeV. 6 refs, 9 figs

  14. In-vivo assessment of whole-body radioisotope burdens at the Los Alamos National Laboratory

    International Nuclear Information System (INIS)

    Vasilik, D.G.; Aikin, I.C.

    1983-08-01

    The Los Alamos National Laboratory program for in-vivo measurements includes the capability for the whole-body assessment of body burdens for x-ray or gamma-ray emitting radioisotopes. This capability is an important part of the health and safety program at Los Alamos where a wide variety of radioisotopes are utilized. This report addresses the whole body portion of our in-vivo measurement capabilities. Whole-body measurements at Los Alamos make use of a hyperpure germanium (HpGe) detector and a lithium-drifted germanium [Ge(Li)] detector for identification and quantification of radioisotopes. Analysis results are interpreted in terms of two basic statistical measures of detection limits. One measure is called the minimum significant measured activity (MSMA), which is interpreted as meaning that there is some activity in the body. The second measure is called the minimum detectable true activity (MDTA), which is defined as the smallest amount of activity required to be in the body in order that a measurement of an individual can be expected to imply correctly the presence of activity with a predetermined degree of confidence. 7 references, 8 figures

  15. Critical concentrations of cadmium in human liver and kidney measured by prompt-gamma neutron activation

    International Nuclear Information System (INIS)

    Cohn, S.H.; Vartsky, D.; Yasumura, S.; Zanzi, I.; Ellis, K.J.

    1979-01-01

    Few data exist on Cd metabolism in human beings. In particular, data are needed on the role of parameters such as age, sex, weight, diet, smoking habits, and state of health. Prompt-gamma neutron activation analysis (PGNAA) provides the only currently available means for measuring in vivo levels of liver and kidney Cd. The method employs an 85 Ci, 235 Pu,Be neutron source and a gamma ray detection system consisting of two Ge(Li) detector. The dose delivered to the liver and left kidney is 666 mrem (detection limit is 1.4 μg/g Cd in the liver and 2.0 mg Cd for one kidney). Absolute levels of Cd in the kidney and concentrations of Cd in the liver were measured in vivo in twenty healthy adult males using 238 Pu,Be neutron sources. Organ Cd levels of smokers were significantly elevated above those of nonsmokers. Biological half-time for Cd in the body was estimated to be 15.7 yr. Cigarette smoking was estimated to result in the absorption of 1.9 μg of Cd per pack. No relationship was bound between body stores of Cd (liver and kidney) and Cd or β-microglobulin levels in urine and blood. Currently the above neutron activation facility is being mounted on a 34-ft mobile trailer unit. This unit will be used to monitor levels of Cd in industrial workers. It is anticipated that critically important data, particularly on industrially exposed workers, will provide a better basis for determining critical concentrations and for the setting or revision of standards for industrial and environmental Cd pollution

  16. A gamma-ray therapeutic system applied to treatment of body

    International Nuclear Information System (INIS)

    Huang Yu; Duan Zhengcheng; Zhu Guoli; Gong Shihua; Li Xiaoping

    2004-01-01

    In order to treat malignant tumors in human body, a stereotactic gamma-ray whole-body therapeutic system has been developed. This system is a typical large mechatronics treatment machine. In this paper, its main working principles and characteristics are introduced. This system comprises a special gallows frame with an open vertical structure, a changeable collimator device by which the size of convergence center can be chosen, and a 3D treatment couch. A computer brings the couch to target position automatically. Therefore precise and dynamic rotary converging therapy for tumors located anywhere in the body has been realized. The system's performance has been proved in practice, which includes good curative effect, reliable automation, and safe and secure operation. (authors)

  17. ICF ignition capsule neutron, gamma ray, and high energy x-ray images

    Science.gov (United States)

    Bradley, P. A.; Wilson, D. C.; Swenson, F. J.; Morgan, G. L.

    2003-03-01

    Post-processed total neutron, RIF neutron, gamma-ray, and x-ray images from 2D LASNEX calculations of burning ignition capsules are presented. The capsules have yields ranging from tens of kilojoules (failures) to over 16 MJ (ignition), and their implosion symmetry ranges from prolate (flattest at the hohlraum equator) to oblate (flattest towards the laser entrance hole). The simulated total neutron images emphasize regions of high DT density and temperature; the reaction-in-flight neutrons emphasize regions of high DT density; the gamma rays emphasize regions of high shell density; and the high energy x rays (>10 keV) emphasize regions of high temperature.

  18. Imaging of heterogeneous materials by prompt gamma-ray neutron activation analysis

    International Nuclear Information System (INIS)

    Staples, P.; Prettyman, T.; Lestone, J.

    1998-01-01

    The authors have used a tomographic gamma scanner (TGS) to produce tomographic prompt gamma-ray neutron activation analysis imaging (PGNAA) of heterogeneous matrices. The TGS was modified by the addition of graphite reflectors that contain isotopic neutron sources for sample interrogation. The authors are in the process of developing the analysis methodology necessary for a quantitative assay of large containers of heterogeneous material. This nondestructive analysis (NDA) technique can be used for material characterization and the determination of neutron assay correction factors. The most difficult question to be answered is the determination of the source-to-sample coupling term. To assist in the determination of the coupling term, the authors have obtained images for a range of sample that are very well characterized, such as, homogenous pseudo one-dimensional samples to three-dimensional heterogeneous samples. They then compare the measurements to MCNP calculations. For an accurate quantitative measurement, it is also necessary to determine the sample gamma-ray self attenuation at higher gamma-ray energies, namely pair production should be incorporated into the analysis codes

  19. In vivo neutron activation facility at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Ma, R.; Yasumura, Seiichi; Dilmanian, F.A.

    1997-11-01

    Seven important body elements, C, N, Ca, P, K, Na, and Cl, can be measured with great precision and accuracy in the in vivo neutron activation facilities at Brookhaven National Laboratory. The facilities include the delayed-gamma neutron activation, the prompt-gamma neutron activation, and the inelastic neutron scattering systems. In conjunction with measurements of total body water by the tritiated-water dilution method several body compartments can be defined from the contents of these elements, also with high precision. In particular, body fat mass is derived from total body carbon together with total body calcium and nitrogen; body protein mass is derived from total body nitrogen; extracellular fluid volume is derived from total body sodium and chlorine; lean body mass and body cell mass are derived from total body potassium; and, skeletal mass is derived from total body calcium. Thus, we suggest that neutron activation analysis may be valuable for calibrating some of the instruments routinely used in clinical studies of body composition. The instruments that would benefit from absolute calibration against neutron activation analysis are bioelectric impedance analysis, infrared interactance, transmission ultrasound, and dual energy x-ray/photon absorptiometry.

  20. Use of digital computers for correction of gamma method and neutron-gamma method indications

    International Nuclear Information System (INIS)

    Lakhnyuk, V.M.

    1978-01-01

    The program for the NAIRI-S computer is described which is intended for accounting and elimination of the effect of by-processes when interpreting gamma and neutron-gamma logging indications. By means of slight corrections it is possible to use the program as a mathematical basis for logging diagram standardization by the method of multidimensional regressive analysis and estimation of rock reservoir properties

  1. Active neutron and gamma-ray imaging of highly enriched uranium for treaty verification.

    Science.gov (United States)

    Hamel, Michael C; Polack, J Kyle; Ruch, Marc L; Marcath, Matthew J; Clarke, Shaun D; Pozzi, Sara A

    2017-08-11

    The detection and characterization of highly enriched uranium (HEU) presents a large challenge in the non-proliferation field. HEU has a low neutron emission rate and most gamma rays are low energy and easily shielded. To address this challenge, an instrument known as the dual-particle imager (DPI) was used with a portable deuterium-tritium (DT) neutron generator to detect neutrons and gamma rays from induced fission in HEU. We evaluated system response using a 13.7-kg HEU sphere in several configurations with no moderation, high-density polyethylene (HDPE) moderation, and tungsten moderation. A hollow tungsten sphere was interrogated to evaluate the response to a possible hoax item. First, localization capabilities were demonstrated by reconstructing neutron and gamma-ray images. Once localized, additional properties such as fast neutron energy spectra and time-dependent neutron count rates were attributed to the items. For the interrogated configurations containing HEU, the reconstructed neutron spectra resembled Watt spectra, which gave confidence that the interrogated items were undergoing induced fission. The time-dependent neutron count rate was also compared for each configuration and shown to be dependent on the neutron multiplication of the item. This result showed that the DPI is a viable tool for localizing and confirming fissile mass and multiplication.

  2. Discrimination methods between neutron and gamma rays for boron loaded plastic scintillators

    CERN Document Server

    Normand, S; Haan, S; Louvel, M

    2002-01-01

    Boron loaded plastic scintillators exhibit interesting properties for neutron detection in nuclear waste management and especially in investigating the amount of fissile materials when enclosed in waste containers. Combining a high thermal neutron efficiency and a low mean neutron lifetime, they are suitable in neutron multiplicity counting. However, due to their high sensitivity to gamma rays, pulse shape discrimination methods need to be developed in order to optimize the passive neutron assay measurement. From the knowledge of their physical properties, it is possible to separate the three kinds of particles that have interacted in the boron loaded plastic scintillator (gamma, fast neutron and thermal neutron). For this purpose, we have developed and compared the two well known discrimination methods (zero crossing and charge comparison) applied for the first time to boron loaded plastic scintillator. The setup for the zero crossing discrimination method and the charge comparison methods is thoroughly expl...

  3. FMCEIR: a Monte Carlo program for solving the stationary neutron and gamma transport equation

    International Nuclear Information System (INIS)

    Taormina, A.

    1978-05-01

    FMCEIR is a three-dimensional Monte Carlo program for solving the stationary neutron and gamma transport equation. It is used to study the problem of neutron and gamma streaming in the GCFR and HHT reactor channels. (G.T.H.)

  4. 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)

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

    International Nuclear Information System (INIS)

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

    1994-01-01

    The effects of neutrons and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10 13 n/cm 2 and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are given in this paper. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed

  6. Neutron and gamma-ray spectra of {sup 239}PuBe and {sup 241}AmBe

    Energy Technology Data Exchange (ETDEWEB)

    Vega-Carrillo, H.R. E-mail: rvega@cantera.reduaz.mx; Manzanares-Acuna, Eduardo; Becerra-Ferreiro, A.M.; Carrillo-Nunez, Aureliano

    2002-08-01

    Neutron and gamma-ray spectra of {sup 239}PuBe and {sup 241}AmBe were measured and their dosimetric features were calculated. Neutron spectra were measured using a multisphere neutron spectrometer with a {sup 6}LiI(Eu) scintillator. The {sup 239}PuBe neutron spectrum was measured in an open environment, while the {sup 241}AmBe neutron spectrum was measured in a closed environment. Gamma-ray spectra were measured using a NaI(Tl) scintillator using the same experimental conditions for both sources. The effect of measuring conditions for the {sup 241}AmBe neutron spectrum indicates the presence of epithermal and thermal neutrons. The low-resolution neutron spectra obtained with the multisphere spectrometer allows one to calculate the dosimetric features of neutron sources. At 100 cm both sources produce approximately the same count rate as that of the 4.4 MeV gamma-ray per unit of alpha emitter activity.

  7. First results on irradiation of ceramic parallel plate chambers with gammas and neutrons

    International Nuclear Information System (INIS)

    Arefiev, A.; Bencze, Gy.L.; Bizzeti, A.; Choumilov, E.; Civinini, C.; Dajko, G.; D'Alessandro, R.; Fenyvesi, A.; Ferrando, A.; Fouz, M.C.; Iglesias, A.; Ivochkin, V.; Josa, M.I.; Malinin, A.; Meschini, M.; Molnar, J.; Pojidaev, V.; Salicio, J.M.; Tanko, L.; Vesztergombi, G.

    1996-01-01

    Ceramic parallel plate chambers were irradiated with gamma rays and neutrons. Results on radiation resistance are presented after 60 Mrad gamma and 0.5.10 16 neutrons per cm 2 irradiation of the detector surface. Results of activation analysis of chambers made of two different ceramic materials are also presented. (orig.)

  8. Estimation of throium deposited in thorotrast patients by whole body counter

    International Nuclear Information System (INIS)

    Tatsumi-Miyajima, Junko; Okajima, Shunzo; Takao, Hideaki; Norimura, Toshiyuki.

    1986-01-01

    Thorotrast, a colloidal solution of thorium dioxide was injected to wounded soldiers, for angiography from 1930 to 1945. The patients who received Thorotrast are interesting objects for finding a biological effect due to the internal irradiation by 232 Th. To determine a distribution and body burden of 232 Th, forty-one Thorotrast patients were measured their gamma-rays with a pair of NaI(T1) scintillation detectors coaxially positioned above and below the coach in the whole body counter of Nagasaki University. The comparison between the usual method using constant values and the method using individual values depend on the organ positions determined with CT (Computed Tomography) scanner for patients was performed to estimate the errors due to the individual differences in the detection efficiency of 232 Th. From the results, the estimates by the whole body counter of the amounts of 232 Th deposits in abdominal region were obtained within the uncertainties of 16 %. And the absorbed dose in the liver and the spleen was also estimated from the amounts of 232 Th. (author)

  9. Neutron induced gamma spectrometry for on-line compositional analysis in coal conversion and fluidized-bed combustion plants

    International Nuclear Information System (INIS)

    Herzenberg, C.L.; O'Fallon, N.M.; Yarlagadda, B.S.; Doering, R.W.; Cohn, C.E.; Porges, K.G.; Duffey, D.

    1977-01-01

    Nuclear techniques involving relatively penetrating radiation may offer the possibility of non-invasive, continuous on-line instrumental monitoring which is representative of the full process stream. Prompt gamma rays following neutron capture are particularly attractive because the penetrating power of the neutrons and the, typically several MeV, capture gammas makes possible interrogation of material within a pipe. We are evaluating neutron capture gamma techniques for this application, both for elemental composition monitoring and for mass-flow measurement purposes, and this paper will present some recent work on composition analysis by neutron induced gamma spectrometry

  10. Simulation of Neutron-Induced Prompt Gamma-ray Spectra Emitted from Fake Tungsten Gold Bar

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K. M.; Sum, G. M. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Fake gold bars on the market cannot be identified easily without testing because they have the same appearance as a pure gold bar. A non-destructive monitoring method is needed to avoid the trading of fake gold bars on the market. The ultimate goal of this study is to find a fake gold bar detection method using a PGAA (Prompt Gamma Activation Analysis). Using existing data, the number of neutron capture for gold and tungsten in fake tungsten gold bar was calculated and a Monte Carlo simulation for the prompt neutron-induced gamma-ray spectra was conducted. A simulation for neutron-induced prompt gamma-rays spectra when a neutron beam is irradiated onto pure and fake gold bars was successfully conducted. Through a comparison between the prompt gamma-ray spectra of the pure gold bar and those of the fake gold bar, it was concluded that the observation of prompt high-energy gamma-rays from tungsten or a reduction of prompt gamma-rays from gold can be evidence of a fake gold bar. The possibility for detecting a fake gold bar using a PGAA facility was verified.

  11. Simulation of Neutron-Induced Prompt Gamma-ray Spectra Emitted from Fake Tungsten Gold Bar

    International Nuclear Information System (INIS)

    Lee, K. M.; Sum, G. M.

    2016-01-01

    Fake gold bars on the market cannot be identified easily without testing because they have the same appearance as a pure gold bar. A non-destructive monitoring method is needed to avoid the trading of fake gold bars on the market. The ultimate goal of this study is to find a fake gold bar detection method using a PGAA (Prompt Gamma Activation Analysis). Using existing data, the number of neutron capture for gold and tungsten in fake tungsten gold bar was calculated and a Monte Carlo simulation for the prompt neutron-induced gamma-ray spectra was conducted. A simulation for neutron-induced prompt gamma-rays spectra when a neutron beam is irradiated onto pure and fake gold bars was successfully conducted. Through a comparison between the prompt gamma-ray spectra of the pure gold bar and those of the fake gold bar, it was concluded that the observation of prompt high-energy gamma-rays from tungsten or a reduction of prompt gamma-rays from gold can be evidence of a fake gold bar. The possibility for detecting a fake gold bar using a PGAA facility was verified

  12. High Energy Neutron Induced Gamma Production

    International Nuclear Information System (INIS)

    Brown, D.A.; Johnson, M.; Navratil, P.

    2007-01-01

    N Division has an interest in improving the physics and accuracy of the gamma data it provides to its customers. It was asked to look into major gamma producing reactions for 14 MeV incident neutrons for several low-Z materials and determine whether LLNL's processed data files faithfully represent the current state of experimental and theoretical knowledge for these reactions. To address this, we surveyed the evaluations of the requested materials, made recommendations for the next ENDL release and noted isotopes that will require further experimental study. This process uncovered several major problems in our translation and processing of the ENDF formatted evaluations, most of which have been resolved

  13. Caffeine-induced hematological changes after whole-body irradiation in rat

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Kyu [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Kim, Ji Hyang; Yoon Yong Dal [Hanyang University, Seoul (Korea, Republic of)

    2004-07-01

    Recent research indicated dietary antioxidants were useful radioprotectors to protect organisms against radiation-induced tissue lethality and other deleterious effects. Radioprotective effects of vitamin C have been demonstrated in certain cells and animals, which would result from scavenging free radicals. Moreover, the previous studies indicated that caffeine had been shown to potently act the radioprotector in irradiated mice. However it is not clear exactly about effects of caffeine treatments chronically after irradiation. So the present studies were designed to identify the hematological effect of caffeine treatments chronically one month after whole-body gamma irradiation.

  14. 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.

  15. Uses of neutron capture gamma-rays in environmental pollution applications

    International Nuclear Information System (INIS)

    AbdAl-Samad, M.A.

    1998-01-01

    As a sensitive and accurate technique, the prompt gamma-rays neutron activation is used with success for elemental analysis. The advantages of this method over the other techniques are rapidity, usage of relatively large sample size and high reliability, beside the detection of the elements which have no gamma activity during the delayed neutron activation analysis or very short lived isotopes. Actually different techniques could be used for estimating the trace, minor and major elements of these environmental samples which are considered as complex samples. In the mean time the neutron activation analysis techniques have been improved and have become an excellent tool for elemental analysis of complex samples (Duffey et al., 1970; Senftle et al., 1971; Henkelmm and Born, 1973 ; Hassan et al., .; 1981, 1982, 1983; Clyton et al., 1983; Zaghloul et al., 1993) and the advantages of the prompt γ- ray neutron activation analysis over the other techniques put this technique in the fore front

  16. The evolution of whole-body imaging.

    LENUS (Irish Health Repository)

    Moran, Deirdre E

    2012-02-01

    This article reviews the evolution of whole-body imaging, discussing the history and development of radiography, nuclear medicine, computed tomography (CT), positron emission tomography (PET), combined PET-CT, and magnetic resonance imaging. The obstacles hindering progress toward whole-body imaging using each of these modalities, and the technical advances that were developed to overcome them, are reviewed. The effectiveness and the limitations of whole-body imaging with each of these techniques are also briefly discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Liu, E-mail: liuyan@nint.ac.cn [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an 710024 (China); School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Wei, Chen; Shanchao, Yang; Xiaoming, Jin [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an 710024 (China); Chaohui, He [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China)

    2016-09-21

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

  18. Laboratory tests on neutron shields for gamma-ray detectors in space

    CERN Document Server

    Hong, J; Hailey, C J

    2000-01-01

    Shields capable of suppressing neutron-induced background in new classes of gamma-ray detectors such as CdZnTe are becoming important for a variety of reasons. These include a high cross section for neutron interactions in new classes of detector materials as well as the inefficient vetoing of neutron-induced background in conventional active shields. We have previously demonstrated through Monte-Carlo simulations how our new approach, supershields, is superior to the monolithic, bi-atomic neutron shields which have been developed in the past. We report here on the first prototype models for supershields based on boron and hydrogen. We verify the performance of these supershields through laboratory experiments. These experimental results, as well as measurements of conventional monolithic neutron shields, are shown to be consistent with Monte-Carlo simulations. We discuss the implications of this experiment for designs of supershields in general and their application to future hard X-ray/gamma-ray experiments...

  19. A Unique Outside Neutron and Gamma Ray Instrumentation Development Test Facility at NASA's Goddard Space Flight Center

    Science.gov (United States)

    Bodnarik, J.; Evans, L.; Floyd, S.; Lim, L.; McClanahan, T.; Namkung, M.; Parsons, A.; Schweitzer, J.; Starr, R.; Trombka, J.

    2010-01-01

    An outside neutron and gamma ray instrumentation test facility has been constructed at NASA's Goddard Space Flight Center (GSFC) to evaluate conceptual designs of gamma ray and neutron systems that we intend to propose for future planetary lander and rover missions. We will describe this test facility and its current capabilities for operation of planetary in situ instrumentation, utilizing a l4 MeV pulsed neutron generator as the gamma ray excitation source with gamma ray and neutron detectors, in an open field with the ability to remotely monitor and operate experiments from a safe distance at an on-site building. The advantage of a permanent test facility with the ability to operate a neutron generator outside and the flexibility to modify testing configurations is essential for efficient testing of this type of technology. Until now, there have been no outdoor test facilities for realistically testing neutron and gamma ray instruments planned for solar system exploration

  20. Experimental arrangement for production and use of gamma radiation from neutron capture

    International Nuclear Information System (INIS)

    Mafra, Olga Yajgunovitch

    1969-01-01

    This dissertation presents the main characteristics and construction details of collimator system for gamma radiation emitted by atomic nuclei after capturing thermal neutrons. This construction was made in one of the cross channels of IEAR-1 swimming pool reactor of the Atomic Energy Institute of Sao Paulo, Brazil. The energies of gamma radiation available vary range from about 4 MeV and 11 MeV, discreetly. With this experimental arrangement is obtained: high intensity, good collimation and monochrome gamma radiation, important for conducting experiments with gamma radiation. It is also present in this dissertation the description of the techniques employed in determining the intensity of gamma radiation and the extent of contamination in the neutron beam as well as the program list GAMAU that adjusts the gamma spectrum photopeak taken as a Gaussian curve. We intend to use this experimental arrangement for the measurement of cross sections of photonuclear reactions

  1. Gamma-ray spectroscopy of neutron-rich products of heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, M.P.; Janssens, R.V.F.; Ahmad, I. [and others

    1995-08-01

    Thick-target {gamma}{gamma} coincidence techniques are being used to explore the spectroscopy of otherwise hard-to-reach neutron-rich products of deep-inelastic heavy ion reactions. Extensive {gamma}{gamma} coincidence measurements were performed at ATLAS using pulsed beams of {sup 80}Se, {sup 136}Xe, and {sup 238}U on lead-backed {sup 122,124}Sn targets with energies 10-15% above the Coulomb barrier. Gamma-ray coincidence intensities were used to map out yield distributions with A and Z for even-even product nuclei around the target and around the projectile. The main features of the yield patterns are understandable in terms of N/Z equilibration. We had the most success in studying the decays of yrast isomers. Thus far, more than thirty new {mu}s isomers in the Z = 50 region were found and characterized. Making isotopic assignments for previously unknown {gamma}-ray cascades proves to be one of the biggest problems. Our assignments were based (a) on rare overlaps with radioactivity data, (b) on the relative yields with different beams, and (c) on observed cross-coincidences between {gamma} rays from light and heavy reaction partners. However, the primary products of deep inelastic collisions often are sufficiently excited for subsequent neutron evaporation, so {gamma}{gamma} cross-coincidence results require careful interpretation.

  2. Technical Aspect for Operating Portable Prompt Gamma Neutron Activation Analysis (PGNAA) on Terengganu Inscribed Stone

    International Nuclear Information System (INIS)

    Rasif Mohd Zain; Hearie Hassan; Roslan Yahya

    2015-01-01

    Prompt Gamma Neutron Activation analysis (PGNAA) is a type of neutron activation analysis which can determined element with nearly no gamma ray decay after being irradiated by neutron sourced. Thus, element that cannot be determined by the conventional NAA for example H, B, N, Si and Cd, can be determine by PGNAA. This paper focuses on the technical working procedure for operating portable PGNAA in field work. The device is designed as a portable non-destructive investigation tool applying an isotopic neutron source (Cf-252) and a gamma-ray spectroscopy system for in-situ investigation. The studied have been carried out on Terengganu inscribed stone at Terengganu State Museum. (author)

  3. Imaging of heterogeneous materials by prompt gamma-ray neutron activation analysis

    International Nuclear Information System (INIS)

    Staples, Parrish; Prettyman, Tom; Lestone, John

    1999-01-01

    We have used a Tomographic Gamma Scanner (TGS) to produce tomographic Prompt Gamma-Ray Neutron Activation Imaging of heterogeneous matrices [T.H. Prettyman, R.J. Estep, G.A. Sheppard, Trans. Am. Nucl. Soc. 69 (1993) 183-184]. The TGS was modified by the addition of graphite reflectors that contain isotopic neutron sources for sample interrogation. We are in the process of developing the analysis methodology necessary for a quantitative assay of large containers of heterogeneous material. This nondestructive analysis technique can be used for material characterization and the determination of neutron assay correction factors. The most difficult question to be answered is the determination of the source to sample coupling term. To assist in the determination of the coupling term we have obtained images for a range of samples that are very well characterized; such as, homogenous pseudo one-dimensional samples to three-dimensional heterogeneous samples. We then compare the measurements to Monte Carlo N-particle calculations. For an accurate quantitative measurement it is also necessary to determine the sample gamma-ray self attenuation at higher gamma-ray energies, namely pair production should be incorporated into the analysis codes

  4. Database of prompt gamma rays from slow neutron capture for elemental analysis

    International Nuclear Information System (INIS)

    Firestone, R.B.; Choi, H.D.; Lindstrom, R.M.; Molnar, G.L.; Mughabghab, S.F.; Paviotti-Corcuera, R.; Revay, Zs; Trkov, A.; Zhou, C.M.; Zerkin, V.

    2004-01-01

    The increasing importance of Prompt Gamma-ray Activation Analysis (PGAA) in a broad range of applications is evident, and has been emphasized at many meetings related to this topic (e.g., Technical Consultants' Meeting, Use of neutron beams for low- and medium-flux research reactors: radiography and materials characterizations, IAEA Vienna, 4-7 May 1993, IAEA-TECDOC-837, 1993). Furthermore, an Advisory Group Meeting (AGM) for the Coordination of the Nuclear Structure and Decay Data Evaluators Network has stated that there is a need for a complete and consistent library of cold- and thermal neutron capture gamma ray and cross-section data (AGM held at Budapest,14-18 October 1996, INDC(NDS)-363); this AGM also recommended the organization of an IAEA CRP on the subject. The International Nuclear Data Committee (INDC) is the primary advisory body to the IAEA Nuclear Data Section on their nuclear data programs. At a biennial meeting in 1997, the INDC strongly recommended that the Nuclear Data Section support new measurements and update the database on Neutron-induced Prompt Gamma-ray Activation Analysis (21st INDC meeting, INDC/P(97)-20). As a consequence of the various recommendations, a CRP on ''Development of a Database for Prompt Gamma-ray Neutron Activation Analysis (PGAA)'' was initiated in 1999. Prior to this project, several consultants had defined the scope, objectives and tasks, as approved subsequently by the IAEA. Each CRP participant assumed responsibility for the execution of specific tasks. The results of their and other research work were discussed and approved by the participants in research co-ordination meetings (see Summary reports: INDC(NDS)-411, 2000; INDC(NDS)-424, 2001; and INDC(NDS)-443, 200). PGAA is a non-destructive radioanalytical method, capable of rapid or simultaneous ''in-situ'' multi-element analyses across the entire Periodic Table, from hydrogen to uranium. However, inaccurate and incomplete data were a significant hindrance in the

  5. Resistive plate chamber neutron and gamma sensitivity measurement with a {sup 252}Cf source

    Energy Technology Data Exchange (ETDEWEB)

    Abbrescia, M.; Altieri, S.; Baratti, V.; Barnaba, O.; Belli, G.; Bruno, G.; Colaleo, A.; DeVecchi, C.; Guida, R. E-mail: roberto.guida@pv.infn.it; Iaselli, G.; Imbres, E.; Loddo, F.; Maggi, M.; Marangelli, B.; Musitelli, G.; Nardo, R.; Natali, S.; Nuzzo, S.; Pugliese, G.; Ranieri, A.; Ratti, S.; Riccardi, C.; Romano, F.; Torre, P.; Vicini, A.; Vitulo, P.; Volpe, F

    2003-06-21

    A bakelite double gap Resistive Plate Chamber (RPC), operating in avalanche mode, has been exposed to the radiation emitted from a {sup 252}Cf source to measure its neutron and gamma sensitivity. One of the two gaps underwent the traditional electrodes surface coating with linseed oil. RPC signals were triggered by fission events detected using BaF{sub 2} scintillators. A Monte Carlo code, inside the GEANT 3.21 framework with MICAP interface, has been used to identify the gamma and neutron contributions to the total number of collected RPC signals. A neutron sensitivity of (0.63{+-}0.02)x10{sup -3} (average energy 2 MeV) and a gamma sensitivity of (14.0{+-}0.5)x10{sup -3} (average energy 1.5 MeV) have been measured in double gap mode. Measurements done in single gap mode have shown that both neutron and gamma sensitivity are independent of the oiling treatment.

  6. The bird's-eye views of the whole body bone scans

    Energy Technology Data Exchange (ETDEWEB)

    Machida, K; Akaike, A; Hayashi, S; Watari, T; Yasukochi, H [Tokyo Univ. (Japan). Faculty of Medicine

    1975-07-01

    Using a newly developed whole body gamma scanner (Toshiba-RDA-601), the authors recorded whole body bone scans in 5 patients (two normal, osteomalacia, bone metastases of prostate cancer and bone metastases of breast cancer), and compared the regular scintiscans with those of bird's-eye view images which were made with the data processor of the scanner. The scans were started about 2 hours after intravenous injection of 3 to 8 mCi of sup(99m)Tc-monofluorophosphate stannous fluoride. The recorded bird's-eye view scans displayed the skeletal system vividly as they were, and the distribution of radioactivity semiquantitatively. It was concluded that the bird'eye view scan is superior to the regular scan, in view of the point that it expresses the distribution of radioactivity semiquantitatively and enables one to know the amount of abnormally accumulated radioactivities by measuring the height of the peak of the diseased area, although this is very difficult in the regular scan. More clinical studies are needed in order to determine which is better for detecting abnormal part clinically.

  7. Effects of low-dose gamma and neutron radiation on genotoxicity and cytotoxicity of reticulocytes in a mouse model

    International Nuclear Information System (INIS)

    Phan, N.; McFarlane, N.M.; Lemon, J.; Boreham, D.R.

    2008-01-01

    Using a successful new automation of micronucleated reticulocyte (MN-RET) scoring, the effects of low-dose (< 1.0 Gy) gamma and neutron radiation on genotoxicity and cytotoxicity of reticulocytes (RET) in a mouse model were investigated. Gamma and neutron irradiation induced significant (p<0.001) increases in the levels of %MN-RET and decreases in the levels of %RET (p<0.001) as the dose level increased. Increasing dose levels showed that gamma radiation induced significantly (p<0.05) more %MN-RET and more %RET than neutron radiation. The results suggest that neutron irradiation may be more cytotoxic (less %RET) than gamma irradiation; however, gamma irradiation may be producing cells with more chromosomal aberrations (more %MN-RET) than neutron irradiation. (author)

  8. Effects of low-dose gamma and neutron radiation on genotoxicity and cytotoxicity of reticulocytes in a mouse model

    Energy Technology Data Exchange (ETDEWEB)

    Phan, N.; McFarlane, N.M.; Lemon, J.; Boreham, D.R. [McMaster Univ., Medical Physics and Applied Radiation Sciences Unit, Hamilton, Ontario (Canada)

    2008-07-01

    Using a successful new automation of micronucleated reticulocyte (MN-RET) scoring, the effects of low-dose (< 1.0 Gy) gamma and neutron radiation on genotoxicity and cytotoxicity of reticulocytes (RET) in a mouse model were investigated. Gamma and neutron irradiation induced significant (p<0.001) increases in the levels of %MN-RET and decreases in the levels of %RET (p<0.001) as the dose level increased. Increasing dose levels showed that gamma radiation induced significantly (p<0.05) more %MN-RET and more %RET than neutron radiation. The results suggest that neutron irradiation may be more cytotoxic (less %RET) than gamma irradiation; however, gamma irradiation may be producing cells with more chromosomal aberrations (more %MN-RET) than neutron irradiation. (author)

  9. A real-time neutron-gamma discriminator based on the support vector machine method for the time-of-flight neutron spectrometer

    Science.gov (United States)

    Wei, ZHANG; Tongyu, WU; Bowen, ZHENG; Shiping, LI; Yipo, ZHANG; Zejie, YIN

    2018-04-01

    A new neutron-gamma discriminator based on the support vector machine (SVM) method is proposed to improve the performance of the time-of-flight neutron spectrometer. The neutron detector is an EJ-299-33 plastic scintillator with pulse-shape discrimination (PSD) property. The SVM algorithm is implemented in field programmable gate array (FPGA) to carry out the real-time sifting of neutrons in neutron-gamma mixed radiation fields. This study compares the ability of the pulse gradient analysis method and the SVM method. The results show that this SVM discriminator can provide a better discrimination accuracy of 99.1%. The accuracy and performance of the SVM discriminator based on FPGA have been evaluated in the experiments. It can get a figure of merit of 1.30.

  10. Protective Effect of Exogenous Dehydro-epiandrosterone Sulfate (DHEAS) on Liver Cell Organs of Whole Body y-Irradiated Rats

    International Nuclear Information System (INIS)

    Abdel-Fattah, K.I.; El-Gawish, M.A.; Abou-Safi, H.M.

    2005-01-01

    Dehydroepiandrosterone (DHEA) and its sulfate (DHES) are adrenal hormones. They are powerful endogenous antioxidants and are important in protecting the cells from damage. The present work aimed to evaluate the exogenous DHEAS as a protector against the whole body exposure to gamma radiation damages on DNA and RNA content of the nuclear fraction, calcium and acid phosphatase in the mitochondria fraction and glutathione (GSH) and malonaldehyde (MDA) in the cytosol fraction in the liver of male rats. Fifty male albino rats weighing 130-150 g were categorized into the following groups: 1-Control untreated. 2-Exposed to whole body gamma irradiation (6.5 Gy). 3-Received a single oral administration of DHEAS at a dose level of 200 mg/kg b.wt. 4-Administered with DHEAS (200 mg/kg) two h pre-exposure to whole body gamma irradiation (6.5 Gy). Three time intervals were determined for tissue sampling: after one day, one week and two weeks post irradiation (groups 2 and 4) and post administration of DHEAS (group 3). The results showed that: 1- DHEAS has a radioprotective effect on DNA and RNA content decreases in the liver nuclear fraction. 2- It significantly ameliorated the changes in mitochondria Ca21 content and acid phosphatase activity. 3- It improved both GSH and MDA contents in the cytosolic fraction. It could be concluded that, DHEAS showed an obvious protective role against the hazard of gamma radiation on liver cells. Several mechanisms were discussed about its effects. Therefore, more investigations are needed to understand well the role of DHEAS in protecting the animal tissues against ionizing radiation hazard

  11. Effect of neutron and gamma radiations on zeolite and zeotype materials

    International Nuclear Information System (INIS)

    Durrani, S.K.

    1994-01-01

    The influence of gamma and (n, gamma)-radiation on the cation exchange and the structure of zeolite and zeotype materials has been studied. Samples were subjected to different doses of gamma-irradiation varying between 0.5 and 10 MGy and Neutron irradiation flux varied from 1.14 x 10/sup 17/ to 3.88 x /sup 10/sup 17/n cm/sup -2/. Structural effects consequent to gamma irradiation were examined by x-ray diffraction, electron scanning micrographs and FTIR measurements. Neutron and gamma-irradiation and not lead by any appreciable change in the structure, however, the displacement cations to locked-in sites results partial reduced barium and caesium uptake. The decrease of the intensities of the absorption bands of the hydroxy-groups reveals that gamma-irradiation has a strong dehydrating influence. THe effects of gamma-radiation on (UO/sub 2/)/sup 2+/ and Am/sup 3+/ uptake into NH/sub 4/-L and NH/sub 4/-SAPO-34 was also observed. K alpha of the uranyl ions increased with increasing pH up to 6.3. At pH > 3.5, the uranyl ions were precipitated and consequently K alpha values were continued to increased. (author)

  12. Measuring element for the detection and determination of radiation doses of gamma radiation and neutrons

    International Nuclear Information System (INIS)

    Jahn, W.; Piesch, E.

    1975-01-01

    A measuring element detects and proves both gamma and neutron radiation. The element includes a photoluminescent material which stores gamma radiation and particles of arsenic and phosphorus embedded in the photoluminescent material for detecting neutron radiation. (U.S.)

  13. Gamma compensated pulsed ionization chamber wide range neutron/reactor power measurement system

    International Nuclear Information System (INIS)

    Ellis, W.H.

    1975-01-01

    An improved method and system of pulsed mode operation of ionization chambers is described in which a single sensor system with gamma compensation is provided by sampling, squaring, automatic gate selector, and differential amplifier circuit means, employed in relation to chambers sensitized to neutron plus gamma and gamma only to subtract out the gamma component, wherein squaring functions circuits, a supplemental high performance pulse rate system, and operational and display mode selection and sampling gate circuits are utilized to provide automatic wide range linear measurement capability for neutron flux and reactor power. Neon is employed as an additive in the ionization chambers to provide independence of ionized gas kinetics temperature effects, and the pulsed mode of operation provide independence of high temperature insulator leakage effects. (auth)

  14. Directional Stand-off Detection of Fast Neutrons and Gammas Using Angular Scattering Distributions

    Energy Technology Data Exchange (ETDEWEB)

    Vanier P. e.; Dioszegi, I.; Salwen, C.; Forman, L.

    2009-10-25

    We have investigated the response of a DoubleScatter Neutron Spectrometer (DSNS) for sources at long distances (gr than 200 meters). We find that an alternative method for analyzing double scatter data avoids some uncertainties introduced by amplitude measurements in plastic scintillators.Time of flight is used to discriminate between gamma and neutron events, and the kinematic distributions of scattering angles are assumed to apply. Non-relativistic neutrons are most likely to scatter at 45°, while gammas with energies greater than 2 MeV are most likely to be forward scattered. The distribution of scattering angles of fission neutrons arriving from a distant point source generates a 45° cone, which can be back-projected to give the source direction. At the same time, the distribution of Compton-scattered gammas has a maximum in the forward direction, and can be made narrower by selecting events that deposit minimal energy in the first scattering event. We have further determined that the shape of spontaneous fission neutron spectra at ranges gr than 110 m is still significantly different from thecosmic ray background.

  15. In vivo measurements of nitrogen using a neutron activation technique

    International Nuclear Information System (INIS)

    Larsson, L.; Alpsten, M.; Toelli, J.; Drugge, N.; Mattsson, S.

    1986-01-01

    Knowledge of body composition is essential for understanding of many diseases such as obesity, anorexia, cancer, kidney and heart diseases. For many years, total body potassium (TBK) has been used as an estimate of the intracellular protein. In some diseases intracellular- and extracellular protein may vary significantly. Together with TBK, total body nitrogen (TBN) should in these cases be measured to estimate the total protein content. The nitrogen content can be measured by in vivo neutron activation. In this work the authors have used the prompt gamma technique: Thermalized neutrons from a Cf-252-source are captured in (n, δ)-reactions. Prompt 10.8 MeV photons are emitted and can be detected during irradiation. The source is contained in a polyethylene block which forms a collimator surrounded by a phi 1.40 m x 0.80 m water tank. The patient is irradiated from below by a 15 cm x 50 cm neutron field. It is possible to scan the whole patient or to measure a part of the body. A phi 15 cm x 15 cm NaI(T1)-detector is used for detection of the 10.8 MeV photons. The detector is mounted above the patient outside the neutron field

  16. Reactivation of neutron killed mammalian cells by gamma irradiation: The observations, possible mechanism and implication

    International Nuclear Information System (INIS)

    Calkins, J.; Harrison, W.; Einspenner, M.

    1990-01-01

    We have observed that combinations of neutron plus gamma ray exposure can significantly increase the colony forming ability of monkey and human cell cultures over the neutron dose alone. The 'reactivation' of neutron killed mammalian cells by gamma rays is analogous to observations made in lower eukaryotic organisms and fits the pattern termed 'T repair' previously postulated for yeast and protozoans. (orig.)

  17. Evaluation of radio-protective effect of melatonin on whole body irradiation induced liver tissue damage.

    Science.gov (United States)

    Shirazi, Alireza; Mihandoost, Ehsan; Ghobadi, Ghazale; Mohseni, Mehran; Ghazi-Khansari, Mahmoud

    2013-01-01

    Ionizing radiation interacts with biological systems to induce excessive fluxes of free radicals that attack various cellular components. Melatonin has been shown to be a direct free radical scavenger and indirect antioxidant via its stimulatory actions on the antioxidant system.The aim of this study was to evaluate the antioxidant role of melatonin against radiation-induced oxidative injury to the rat liver after whole body irradiation. In this experimental study,thirty-two rats were divided into four groups. Group 1 was the control group, group 2 only received melatonin (30 mg/kg on the first day and 30 mg/kg on the following days), group 3 only received whole body gamma irradiation of 10 Gy, and group 4 received 30 mg/kg melatonin 30 minutes prior to radiation plus whole body irradiation of 10 Gy plus 30 mg/kg melatonin daily through intraperitoneal (IP) injection for three days after irradiation. Three days after irradiation, all rats were sacrificed and their livers were excised to measure the biochemical parameters malondialdehyde (MDA) and glutathione (GSH). Each data point represents mean ± standard error on the mean (SEM) of at least eight animals per group. A one-way analysis of variance (ANOVA) was performed to compare different groups, followed by Tukey's multiple comparison tests (p<0.05). The results demonstrated that whole body irradiation induced liver tissue damage by increasing MDA levels and decreasing GSH levels. Hepatic MDA levels in irradiated rats that were treated with melatonin (30 mg/kg) were significantly decreased, while GSH levels were significantly increased, when compared to either of the control groups or the melatonin only group. The data suggest that administration of melatonin before and after irradiation may reduce liver damage caused by gamma irradiation.

  18. Biological dosimetry for mixed gamma-neutron field

    International Nuclear Information System (INIS)

    Brandao, J.O.C.; Santos, J.A.L.; Souza, P.L.G.; Lima, F.F.; Vilela, E.C.; Calixto, M.S.; Santos, N.

    2011-01-01

    There is increasing concern about airline crew members (about one million worldwide) exposed to measurable neutrons doses. Historically, cytogenetic biodosimetry assays have been based on quantifying asymmetrical chromosome alterations (dicentrics, centric rings and acentric fragments) in mitogen-stimulated T-lymphocytes in their first mitosis after radiation exposure. Increased levels of chromosome damage in peripheral blood lymphocytes are a sensitive indicator of radiation exposure and they are routinely exploited for assessing radiation absorbed dose after accidental or occupational exposure. Since radiological accidents are not common, not all nations feel that it is economically justified to maintain biodosimetry competence. However, dependable access to biological dosimetry capabilities is completely critical in event of an accident. In this paper the dose-response curve was measured for the induction of chromosomal alterations in peripheral blood lymphocytes after chronic exposure in vitro to mixed gamma-neutron field. Blood was obtained from one healthy donor and exposed to two mixed gamma-neutron field from sources 241 AmBe (20 Ci) at the Neutron Calibration Laboratory (NCL - CRCN/NE - PE - Brazil). The evaluated absorbed doses were 0.2 Gy; 1.0 Gy and 2.5 Gy. The dicentric chromosomes were observed at metaphase, following colcemide accumulation and 1000 well-spread metaphases were analyzed for the presence of dicentrics by two experts after painted by giemsa 5%. The preliminary results showed a linear dependence between radiations absorbed dose and dicentric chromosomes frequencies. Dose-response curve described in this paper will contribute to the construction of calibration curve that will be used in our laboratory for biological dosimetry. (author)

  19. Development of quick scan whole body monitor for in-vivo monitoring of radiation workers and general public

    International Nuclear Information System (INIS)

    Sankhla, Rajesh; Singh, I.S.; Rao, D.D.; Pradeepkumar, K.S.

    2015-01-01

    Whole body monitoring of radiation workers at nuclear facilities is a regulatory requirement and is recommended for assessment of internal contamination due to gamma emitting radio nuclides. Additionally, nuclear accidents like Chernobyl, Fukushima and radiological accidents like Goiania have clearly highlighted the need for in-vivo monitoring of the members of the public during and/or after such accidents. To cater to these requirements, a high throughput, fast screening, standing linear geometry Quick Scan Whole Body Monitor (QS-WBM) is designed, fabricated and commissioned to measure internal contamination due to gamma emitting radio nuclides (E γ >200keV) incorporated in the human body. The system is designed to achieve sensitivity comparable with conventional WBM for 1 - 2 minutes counting time and to accommodate different body sizes of Indian occupational workers. It is calibrated using BARC reference Bottle Mannequin Absorption (BOMAB) type phantom and also using a family of BOMAB type phantoms representative of different age groups namely 1-, 5-, 10-, 15- and 20- years. The developed system will also be highly useful during emergency situations when large numbers of persons are to be monitored in short interval of time. (author)

  20. Whole body monitoring - Goiania

    International Nuclear Information System (INIS)

    Oliveira, C.A.N. de; Lourenco, M.C.; Bertelli Neto, L.; Lucena, E.A. de; Becker, P.H.B.

    1988-01-01

    Due to the radiological Cs accident in Goiania, Goias in September 1987, it became necessary to evaluate internal contamination levels of: - Individual from the general public that for any reason had direct or indirect involvement with the radioactive source (group 1). - Occupationally involved persons (group 2). For each of these groups, procedures of whole body monitoring were developped. In order to attend group 1 individuals, the IRD/CNEN installed a whole body unit in the INAMPS General Hospital of Goiania in 11.08.87, which was later transferred to 121,57 street, Central Sector in Goiania in 2.06.88. In this unit 547 people were monitored, 356 from group 1 and 241 from group 2, until 04.13.88. In the IRD whole body counter installation, 194 individuals were counted, 185 from group 2 and 9 from group 1. The frequency of monitoring of each individual was established according to the Cs activity present in the body or to the job to be assigned. In this paper we will present some burden activity curves for Cs 137 as a function of the time elapsed from the first measurement. There people from group 1 were measured in both counters, the IRD and the Goiania ones. The values obtained in both installations are compatible with the body activity x time curve. (author) [pt

  1. The efficient neutron-gamma pulse shape discrimination with small active volume scintillation detector

    International Nuclear Information System (INIS)

    Phan Van Chuan; Nguyen Duc Hoa; Nguyen Xuan Hai; Nguyen Ngoc Anh; Tuong Thi Thu Huong; Nguyen Nhi Dien; Pham Dinh Khang

    2016-01-01

    A small detector with EJ-301 liquid scintillation was manufactured for the study on the neutron-gamma pulse shape discrimination. In this research, four algorithms, including Threshold crossing time (TCT), Pulse gradient analysis (PGA), Charge comparison method (CCM), and Correlation pattern recognition (CPR) were developed and compared in terms of their discrimination effectiveness between neutrons and gamma rays. The figures of merits (FOMs) obtained for 100 ÷ 2000 keVee (keV energy electron equivalent) neutron energy range show the charge comparison method was the most efficient of the four algorithms. (author)

  2. Measurements of Soil Carbon by Neutron-Gamma Analysis in Static and Scanning Modes.

    Science.gov (United States)

    Yakubova, Galina; Kavetskiy, Aleksandr; Prior, Stephen A; Torbert, H Allen

    2017-08-24

    The herein described application of the inelastic neutron scattering (INS) method for soil carbon analysis is based on the registration and analysis of gamma rays created when neutrons interact with soil elements. The main parts of the INS system are a pulsed neutron generator, NaI(Tl) gamma detectors, split electronics to separate gamma spectra due to INS and thermo-neutron capture (TNC) processes, and software for gamma spectra acquisition and data processing. This method has several advantages over other methods in that it is a non-destructive in situ method that measures the average carbon content in large soil volumes, is negligibly impacted by local sharp changes in soil carbon, and can be used in stationary or scanning modes. The result of the INS method is the carbon content from a site with a footprint of ~2.5 - 3 m 2 in the stationary regime, or the average carbon content of the traversed area in the scanning regime. The measurement range of the current INS system is >1.5 carbon weight % (standard deviation ± 0.3 w%) in the upper 10 cm soil layer for a 1 hmeasurement.

  3. Effects of whole-body cobalt 60 gamma irradiation on the young korean native goats

    International Nuclear Information System (INIS)

    Kim, Jong Gyu; Sung, Jai Ki

    1989-01-01

    This study was carried out to investigate the effects of whole-body cobolt-60 gamma irradiation on clinical signs, mortality, hematological, blood chemical, chromosomal and pathologic changes in the young Korean native goats. Groups of goats were exposed to 200, 400, 600 and 800 rads of gamma irradiation from a cobalt-60 source. Clinical signs such as diarrhea, anorexia, weakness and depression of the irradiated goats were observed. Mortalities were 66.7 percent in the group irradiated with 200 rads and 100 percent in the groups irradiated with higher doses. Death times were shortened with the increment of irradiation doses. With time after irradiation, the values of erythrocytes, hemoglobin and packed cell volume decreased in the 200 and 400 rads groups and increased in the 600 and 800 rads groups. The number of total leukocytes of the irradiated goats decreased significantly in all irradiated groups. The degrees of decrease were severe as the irradiated doses were increased. Significant decrease of lymphocyte counts were observed from 6 hours in the 800 rads group and 1 day post irradiation(PI) in all other groups. Post irradiation times for significant reduction of neutrophils were 1, 3, 3 and 5 days for 800, 600, 400 and 200 rads groups, respectively. Serum sorbitol dehydrogenase and serum aspartate aminotransferase activities increased remarkably at 6 hours PI in the 800 rads group and 1 day PI in all other groups. Thereafter the activities returned to normal values. Since mitoses of lymphocytes were completely inhibited in blood cultures of all irradiated goats, chromosomal pictures could not be observed. However, mitoses were observed on 28 days PI in 200 rads group and no abberration in the number and structures of lymphocyte chromosomes were detected. Histopathologic findings in various organs of the irradiated goats were severe necrosis and depletion of lymphoid cells in the lymph nodes and spleen, hypoplasia of hemopoietic cells in the bone marrow

  4. Electrical characterization of commercial NPN bipolar junction transistors under neutron and gamma irradiation

    Directory of Open Access Journals (Sweden)

    OO Myo Min

    2014-01-01

    Full Text Available Electronics components such as bipolar junction transistors, diodes, etc. which are used in deep space mission are required to be tolerant to extensive exposure to energetic neutrons and ionizing radiation. This paper examines neutron radiation with pneumatic transfer system of TRIGA Mark-II reactor at the Malaysian Nuclear Agency. The effects of the gamma radiation from Co-60 on silicon NPN bipolar junction transistors is also be examined. Analyses on irradiated transistors were performed in terms of the electrical characteristics such as current gain, collector current and base current. Experimental results showed that the current gain on the devices degraded significantly after neutron and gamma radiations. Neutron radiation can cause displacement damage in the bulk layer of the transistor structure and gamma radiation can induce ionizing damage in the oxide layer of emitter-base depletion layer. The current gain degradation is believed to be governed by the increasing recombination current in the base-emitter depletion region.

  5. Creation and validation of a neutron-gamma coupled multigroup cross section library

    International Nuclear Information System (INIS)

    Devan, K.; Gopalakrishnan, V.; Lee, S.M.

    1995-01-01

    The task of creating our own neutron-gamma coupled library was taken up. By using 1985 version of NJOY code system, a coupled set called IGC-DE4-S1 in ANISN format for 25 nuclides has been arrived at based on ENDF/B-IV neutron library and DLC-99 gamma library, with Legendre order of up to 5. The flow chart for the creation of coupled set is given. 5 refs, 1 fig., 3 tabs

  6. Practical methods for the functioning evaluation of the whole body counter system Accuscan II of the ININ

    International Nuclear Information System (INIS)

    Alfaro L, M. M.; Ramirez J, F. J.; Mondragon C, L.

    2013-10-01

    The whole body counter system Accuscan II of the Instituto Nacional de Investigaciones Nucleares (ININ), was designed and built to quantify and to measure radionuclides fission product as well as gamma emitters, with a maximum sensibility of less than 10 n Ci for cobalt 60 at one time of counting of 5 minutes. The system has two detectors of Ge(Hp) with Beryllium window to a relative efficiency of 25% in a counting configuration of vertical scanning, this configuration gives a plane response of constant efficiency. In this work some practical methods developed in the Internal Dosimetry Laboratory to carry out the functioning evaluation of the whole body counter system Accuscan II of the ININ are described. With the obtained results of this evaluation we can decide fine adjustments will be necessary for the optimization of the equipment operation. The evaluation of this equipment was especially necessary, due to its 21 years-old antiquity and for the gradual changes that has in its functioning. The equipment is intrinsically a gamma spectrometry system and some described experiences could be applied too in other gamma spectrometry systems. (Author)

  7. Whole-body counters in Canada

    International Nuclear Information System (INIS)

    Letourneau, C.

    1986-08-01

    A compilation of whole-body counting existing across Canada was prepared by AECB (Atomic Energy Control Board) staff. This work was initiated so that AECB staff and other concerned parties would have this information readily available, especially during urgent situations. This report is to be used for reference purposes only, as it makes no attempt to judge the present state of the art of whole-body counting

  8. Stromal damage in the mouse small intestine after Co60 gamma or D-T neutron irradiation

    International Nuclear Information System (INIS)

    Carr, K.E.; Hamlet, R.; Nias, A.H.; Boyle, F.C.; Fife, M.G.

    1985-01-01

    Stromal constituents have been examined in mouse small intestine 3 1/2 days after irradiation with either 18-20 Gy gamma rays or 10 Gy neutrons. These doses were chosen for their equivalent effect on the number of intestinal crypts found after treatment. Despite the fact that the topography of the villi, as imaged by scanning electron microscopy, was altered by treatment, with gamma irradiated villi showing lateral or horizontal collapse while neutron irradiation produced conical villi, few changes were seen in the villous stromal compartments. There were, however, ultrastructural changes observed in the stroma of the pericryptal plate. Changes common to both radiation schedules included disorganisation of the subepithelial stroma and an increase in the number of irregular processes. Some changes after irradiation, however, were not identical in the two groups. Gamma irradiation resulted in pale, foamy cytoplasmic vesicles, the separation of smooth muscle cells and changes in the structure of the luminal aspect of arterial blood vessels while neutron irradiation produced dense cytoplasmic vesicles and electron dense bodies within the substance of peripheral nerve twigs. The fact that the variation in the topography of villi after the two types of radiation is matched by changes in the deep stroma rather than within the villi themselves indicates that the stromal pericryptal plate is of importance in the structure of the villus and the extent to which the villi have varied from the normal finger shaped structure

  9. Neutron and Gamma Imaging for National Security Applications

    Science.gov (United States)

    Hornback, Donald

    2017-09-01

    The Department of Energy, National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation Research and Development (DNN R&D/NA-22) possesses, in part, the mission to develop technologies in support of nuclear security efforts in coordination with other U.S. government entities, such as the Department of Defense and the Department of Homeland Security. DNN R&D has long supported research in nuclear detection at national labs, universities, and through the small business innovation research (SBIR) program. Research topics supported include advanced detector materials and electronics, detection algorithm development, and advanced gamma/neutron detection systems. Neutron and gamma imaging, defined as the directional detection of radiation as opposed to radiography, provides advanced detection capabilities for the NNSA mission in areas of emergency response, international safeguards, and nuclear arms control treaty monitoring and verification. A technical and programmatic overview of efforts in this field of research will be summarized.

  10. Dosimetry in Thermal Neutron Irradiation Facility at BMRR

    Directory of Open Access Journals (Sweden)

    Hu J.-P.

    2016-01-01

    Full Text Available Radiation dosimetry for Neutron Capture Therapy (NCT has been performed since 1959 at Thermal Neutron Irradiation Facility (TNIF of the three-megawatt light-water cooled Brookhaven Medical Research Reactor (BMRR. In the early 1990s when more effective drug carriers were developed for NCT, in which the eye melanoma and brain tumors in rats were irradiated in situ, extensive clinical trials of small animals began using a focused thermal neutron beam. To improve the dosimetry at irradiation facility, a series of innovative designs and major modifications made to enhance the beam intensity and to ease the experimental sampling at BMRR were performed; including (1 in-core fuel addition to increase source strength and balance flux of neutrons towards two ports, (2 out of core moderator remodeling, done by replacing thicker D2O tanks at graphite-shutter interfacial areas, to expedite neutron thermalization, (3 beam shutter upgrade to reduce strayed neutrons and gamma dose, (4 beam collimator redesign to optimize the beam flux versus dose for animal treatment, (5 beam port shielding installation around the shutter opening area (lithium-6 enriched polyester-resin in boxes, attached with polyethylene plates to reduce prompt gamma and fast neutron doses, (6 sample holder repositioning to optimize angle versus distance for a single organ or whole body irradiation, and (7 holder wall buildup with neutron reflector materials to increase dose and dose rate from scattered thermal neutrons. During the facility upgrade, reactor dosimetry was conducted using thermoluminescent dosimeters TLD for gamma dose estimate, using ion chambers to confirm fast neutron and gamma dose rate, and by the activation of gold-foils with and without cadmium-covers, for fast and thermal neutron flux determination. Based on the combined effect from the size and depth of tumor cells and the location and geometry of dosimeters, the measured flux from cadmium-difference method was 4–7

  11. Dosimetry in Thermal Neutron Irradiation Facility at BMRR

    Energy Technology Data Exchange (ETDEWEB)

    Hu, J. P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Holden, N. E. [Brookhaven National Lab. (BNL), Upton, NY (United States); Reciniello, R. N.

    2014-05-23

    Radiation dosimetry for Neutron Capture Therapy (NCT) has been performed since 1959 at Thermal Neutron Irradiation Facility (TNIF) of the three-megawatt light-water cooled Brookhaven Medical Research Reactor (BMRR). In the early 1990s when more effective drug carriers were developed for NCT, in which the eye melanoma and brain tumors in rats were irradiated in situ, extensive clinical trials of small animals began using a focused thermal neutron beam. To improve the dosimetry at irradiation facility, a series of innovative designs and major modifications made to enhance the beam intensity and to ease the experimental sampling at BMRR were performed; including (1) in-core fuel addition to increase source strength and balance flux of neutrons towards two ports, (2) out of core moderator remodeling, done by replacing thicker D2O tanks at graphite-shutter interfacial areas, to expedite neutron thermalization, (3) beam shutter upgrade to reduce strayed neutrons and gamma dose, (4) beam collimator redesign to optimize the beam flux versus dose for animal treatment, (5) beam port shielding installation around the shutter opening area (lithium-6 enriched polyester-resin in boxes, attached with polyethylene plates) to reduce prompt gamma and fast neutron doses, (6) sample holder repositioning to optimize angle versus distance for a single organ or whole body irradiation, and (7) holder wall buildup with neutron reflector materials to increase dose and dose rate from scattered thermal neutrons. During the facility upgrade, reactor dosimetry was conducted using thermoluminescent dosimeters TLD for gamma dose estimate, using ion chambers to confirm fast neutron and gamma dose rate, and by the activation of gold-foils with and without cadmium-covers, for fast and thermal neutron flux determination. Based on the combined effect from the size and depth of tumor cells and the location and geometry of dosimeters, the measured flux from cadmium-difference method was 4 - 7

  12. Comparison of whole-body-imaging methods

    International Nuclear Information System (INIS)

    Rollo, F.D.; Hoffer, P.

    1977-01-01

    Currently there are four different devices that have found clinical utility in whole-body imaging. These are the rectilinear scanner, the multicrystal whole-body scanner, the Anger-type camera with a whole-body-imaging table, and the tomoscanner. In this text, the basic theory of operation and a discussion of the advantages and disadvantages in whole-body imaging is presented for each device. When applicable, a comparative assessment of the various devices is also presented. As with all else in life, there is no simple answer to the question ''which total body imaging device is best.'' Institutions with a very heavy total-body-imaging load may prefer to use an already available dual-headed rectilinear scanner system for these studies, rather than invest in a new instrument. Institutions with moderate total-body-imaging loads may wish to invest in moving table or moving camera devices which make total body imaging more convenient but retain the basic flexibility of the camera. The large-field Anger camera with or without motion offers another flexible option to these institutions. The laboratory with a very heavy total body imaging load may select efficiency over flexibility, thereby freeing up other instruments for additional studies. Finally, reliability as well as availability and quality of local service must be considered. After all, design features of an instrument become irrelevant when it is broken down and awaiting repair

  13. Dosimetry of mixed gamma - neutron fluxes in the active zone of working reactor and gamma-flux after quenching

    International Nuclear Information System (INIS)

    Mussaeva, M.A.; Zinov'ev, V.; Ibragimova, E.M.; Muminov, M.I.

    2006-01-01

    Full text: For carrying out experiments in the channels of nuclear reactor, it is necessary to know the distribution of neutron flux and the intensity of accompanying gamma-radiation both in the working and quenched regimes. Dosimetric parameter of transparent dielectrics is based on the effect of monotonous changing of optical absorption or luminescence under neutrons and/or gamma-radiation. While the radioactivity induced in an element monitor is proportional only to a neutron fluence beginning from a threshold energy. Therefore the aim of this work was to determine the values of neutron and gamma-component fluxes separately and evaluate the contribution of each into the defect production in dielectrics. We used very pure quartz glass of KU-1 type, produced in Russian State Optical Institute by fusion from SiCl 4 in the mixed flow of O 2 +H 2 (impurities of Cl and OH up to 10 -2 % and the rest - below 10 -4 %), SiO 2 glasses with 30 % Ba, and also pure Ni wire. Since under irradiation in the working reactor samples were undergone mixed neutron and gamma fluxes, we suggested determination of intensity of gamma-radiation from radio-nuclides (products of uranium fission) after quenching the reactor by the current of ionization chamber and glass dosimeters. Samples of SiO 2 -BaO together with Ni monitors were irradiated for 1 hour in 18 channels of the active zone of the working reactor both in the sealed ampoules and in the contact with water of the 1-st cooling circuit at 40 deg C. The linear dependence of the induced optical density on the absorbed dose of n 0 + γ-radiation was obtained. Ni -monitors not sensitive to γ-radiation gained the induced radioactivity proportional to the absorbed energy of neutron flux above 1 MeV. Neutron fluxes in the 18 channels varied from 9.53·10 11 to 1.21·10 13 cm -2 s -1 corresponding to fluences from 3.43·10 15 to 4.3·10 16 cm -2 . Optical density of band 215 nm ascertained to E ' - center, which is ≡ Si * near oxygen

  14. Measurements of angular and energy distributions of gamma-rays resulting from neutron interactions in shielding barriers

    International Nuclear Information System (INIS)

    Makarious, A.S.; Maayouf, R.M.A.; Megahid, R.

    1978-01-01

    Measurements of both angular and energy distributions of secondary gamma resulting from interactions of neutrons emerging from one of the ET-RR-1 reactor beam holes, in barriers from iron, lead and water are reported. The measurements were carried out, both with a bare neutron beam and with the beam being transmitted through a B4C. Filter, using a stilbene crystal gamma spectrometer. The spectrometer applies discrimination between neutrons and gammas according to the difference in decay times of the scintillations produced by them in stilbene. The described angular distributions resulted from measurements made at different angles of neutron incidence and with three different thicknesses of each sample

  15. Gamma signatures of the C-BORD Tagged Neutron Inspection System

    Directory of Open Access Journals (Sweden)

    Sardet A.

    2018-01-01

    Full Text Available In the frame of C-BORD project (H2020 program of the EU, a Rapidly relocatable Tagged Neutron Inspection System (RRTNIS is being developed to non-intrusively detect explosives, chemical threats, and other illicit goods in cargo containers. Material identification is performed through gamma spectroscopy, using twenty NaI detectors and four LaBr3 detectors, to determine the different elements composing the inspected item from their specific gamma signatures induced by fast neutrons. This is performed using an unfolding algorithm to decompose the energy spectrum of a suspect item, selected by X-ray radiography and on which the RRTNIS inspection is focused, on a database of pure element gamma signatures. This paper reports on simulated signatures for the NaI and LaBr3 detectors, constructed using the MCNP6 code. First experimental spectra of a few elements of interest are also presented.

  16. The usefulness of early whole body bone scintigraphy in the detection of bone metastasis from prostatic cancer

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, Nobuaki; Fukunaga, Masao; Furukawa, Yohji; Tanaka, Hiroyoshi [Kawasaki Medical School, Kurashiki, Okayama (Japan)

    1994-06-01

    Early whole body bone scintigraphy was performed on 25 patients with prostatic cancer (15 cases with bone metastases and 10 cases without bone metastasis) to obtain anterior and posterior whole body images five minutes after administration of [sup 99m]Tc-hydroxymethylene diphosphonate(HMDP). The results were compared with the findings of routine bone scintigraphy after three hours, and the usefulness of the above method for the diagnosis of bone metastasis from prostatic cancer was evaluated. In cases in which increased activity was found in the upper and lower lumbar vertebrae by routine bone scintigraphy but no abnormality was seen by early whole body bone scintigraphy, senile degenerative bone changes such as spondylosis deformance were observed by bone radiography. In cases with multiple bone metastases, abnormal multiple accumulations were found by both early whole body bone scintigraphy and routine bone scintigraphy. In addition, in cases showing super bone scan, high accumulation in the skeletal system had already been detected by early whole body bone scintigraphy. When the courses before and after treatment in nine cases of multiple bone metastases were passaged from the results of early whole body bone scintigraphy and from changes in tumor markers (prostatic specific antigen, [gamma]-semino protein and prostatic acid phosphatase), increased activity and the appearance of new hot spots as well as an increase in tumor markers were detected by early whole body scintigraphy in three of the four advanced cases, whereas decreased accumulations and a decrease in and normalization of tumor markers were observed in five improved cases. (author).

  17. 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.

  18. Imaging technique of whole-body scintigram in the event of breakdown of the photomultiplier tube

    International Nuclear Information System (INIS)

    Inagaki, Syoichi; Tonami, Syuichi; Yasui, Masakazu; Sugishita, Kouki; Nakamura, Mamoru; Kuranishi, Makoto

    1997-01-01

    When the PMT and preamplifier are out of order, it is impossible to make a correct diagnosis because of defects on the scintigram. However, repair of the equipment may take a long time. In order to perform emergent whole-body scintigrams in the event of such breakdowns, we have developed a new approach named the lead-shield method. The major principles of this method involve placing a lead shield on the gamma camera such that it corresponds to the area of the abnormal PMT and making use of the normal area of the detector. The lead shield, 2 mm thick and 1.5 times as wide as the defect on a planar image, was situated perpendicular to the scan plane of the whole-body scintigram. The results showed that whole-body scintigrams obtained by the lead-shield method had the same quality as those obtained by the conventional method, and the spatial resolution and uniformity showed nearly no change despite some disadvantages such as lower sensitivity and shorter scan length. The lead-shield method can be a useful tool for the performance of whole-body scintigrams in cases of emergency when the PMT and preamplifier are out of order. (author)

  19. Imaging technique of whole-body scintigram in the event of breakdown of the photomultiplier tube

    Energy Technology Data Exchange (ETDEWEB)

    Inagaki, Syoichi; Tonami, Syuichi; Yasui, Masakazu; Sugishita, Kouki; Nakamura, Mamoru; Kuranishi, Makoto [Toyama Medical and Pharmaceutical Univ. (Japan). Hospital

    1997-10-01

    When the PMT and preamplifier are out of order, it is impossible to make a correct diagnosis because of defects on the scintigram. However, repair of the equipment may take a long time. In order to perform emergent whole-body scintigrams in the event of such breakdowns, we have developed a new approach named the lead-shield method. The major principles of this method involve placing a lead shield on the gamma camera such that it corresponds to the area of the abnormal PMT and making use of the normal area of the detector. The lead shield, 2 mm thick and 1.5 times as wide as the defect on a planar image, was situated perpendicular to the scan plane of the whole-body scintigram. The results showed that whole-body scintigrams obtained by the lead-shield method had the same quality as those obtained by the conventional method, and the spatial resolution and uniformity showed nearly no change despite some disadvantages such as lower sensitivity and shorter scan length. The lead-shield method can be a useful tool for the performance of whole-body scintigrams in cases of emergency when the PMT and preamplifier are out of order. (author)

  20. Gamma-ray-spectroscopy following high-flux 14-MeV neutron activation

    International Nuclear Information System (INIS)

    Williams, R.E.

    1981-01-01

    The Rotating Target Neutron Source (RTNS-I), a high-intensity source of 14-MeV neutrons at the Lawrence Livermore National Laboratory (LLNL), has been used for applications in activation analysis, inertial-confinement-fusion diagnostic development, and fission decay-heat studies. The fast-neutron flux from the RTNS-I is at least 50 times the maximum fluxes available from typical neutron generators, making these applications possible. Facilities and procedures necessary for gamma-ray spectroscopy of samples irradiated at the RTNS-I were developed

  1. Gamma-ray-spectroscopy following high-flux 14-MeV neutron activation

    Energy Technology Data Exchange (ETDEWEB)

    Williams, R.E.

    1981-10-12

    The Rotating Target Neutron Source (RTNS-I), a high-intensity source of 14-MeV neutrons at the Lawrence Livermore National Laboratory (LLNL), has been used for applications in activation analysis, inertial-confinement-fusion diagnostic development, and fission decay-heat studies. The fast-neutron flux from the RTNS-I is at least 50 times the maximum fluxes available from typical neutron generators, making these applications possible. Facilities and procedures necessary for gamma-ray spectroscopy of samples irradiated at the RTNS-I were developed.

  2. Neutron, gamma ray, and temperature effects on the electrical characteristics of thyristors

    Science.gov (United States)

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

    1992-01-01

    Experimental data showing the effects of neutrons, gamma rays, and temperature on the electrical and switching characteristics of phase-control and inverter-type SCR's are presented. The special test fixture built for mounting, heating, and instrumenting the test devices is described. Four SCR's were neutron irradiated at 300 K and four at 365 K for fluences up to 3.2 x 10 exp 13 pn/sq. cm, and eight were gamma irradiated at 300 K only for gamma doses up to 5.1 Mrads. The electrical measurements were made during irradiation and the switching measurements were made only before and after irradiation. Radiation induced crystal defects, resulting primarily from fast neutrons, caused the reduction of minority carrier lifetime through the generation of R-G centers. The reduction in lifetime caused increases in the on-state voltage drop and in the reverse and forward leakage currents, and decreases in the turn-off time.

  3. Neutron, gamma ray, and temperature effects on the electrical characteristics of thyristors

    International Nuclear Information System (INIS)

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

    1992-01-01

    In this paper, experimental data showing the effects of neutrons, gamma rays, and temperature on the electrical and switching characteristics of phase-control and inverter-type SCRs are presented. The special test fixture built for mounting, heating, and instrumenting the test devices is described. Four SCRs were neutron irradiated at 300 K and four at 365 K for fluences up to 3.2 x 10 13 n/cm 2 , and eight were gamma irradiated at 300 K only for gamma doses up to 5.1 Mrads. The electrical measurements were made during irradiation and the switching measurements were made only before and after irradiation. Radiation induced crystal defects, resulting primarily from fast neutrons, caused the reduction of minority carrier lifetime through the generation of R-G centers. The reduction in lifetime caused increases in the on-state voltage drop and in the reverse and forward leakage currents, and decreases in the turn-off time

  4. 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)

  5. Baseline distortion effect on gamma-ray pulse-height spectra in neutron capture experiments

    International Nuclear Information System (INIS)

    Laptev, A.; Harada, H.; Nakamura, S.; Hori, J.; Igashira, M.; Ohsaki, T.; Ohgama, K.

    2005-01-01

    A baseline distortion effect due to gamma-flash at neutron time-of-flight measurement using a pulse neutron source has been investigated. Pulses from C 6 D 6 detectors accumulated by flash-ADC were processed with both standard analog-to-digital converter (ADC) and flash-ADC operational modes. A correction factor of gamma-ray yields, due to baseline shift, was quantitatively obtained by comparing the pulse height spectra of the two data-taking modes. The magnitude of the correction factor depends on the time after gamma-flash and has complex time dependence with a changing sign

  6. RADHEAT-V3, a code system for generating coupled neutron and gamma-ray group constants and analyzing radiation transport

    International Nuclear Information System (INIS)

    Koyama, Kinji; Taji, Yukichi; Miyasaka, Shun-ichi; Minami, Kazuyoshi.

    1977-07-01

    The modular code system RADHEAT is for producing coupled multigroup neutron and gamma-ray cross section sets, analyzing the neutron and gamma-ray transport, and calculating the energy deposition and atomic displacements due to these radiations in a nuclear reactor or shield. The basic neutron cross sections and secondary gamma-ray production data are taken from ENDF/B and POPOP4 libraries respectively. The system (1) generates multigroup neutron cross sections, energy deposition coefficients and atomic displacement factors due to neutron reactions, (2) generates multigroup gamma-ray cross sections and energy transfer coefficients, (3) generates secondary gamma-ray production cross sections, (4) combines these cross sections into the coupled set, (5) outputs and updates the multigroup cross section libraries in convenient formats for other transport codes, (6) analyzes the neutron and gamma-ray transport and calculates the energy deposition and the number density of atomic displacements in a medium, (7) collapses the cross sections to a broad-group structure, by option, using the weighting functions obtained by one-dimensional transport calculation, and (8) plots, by option, multigroup cross sections, and neutron and gamma-ray distributions. Definitions of the input data required in various options of the code system are also given. (auth.)

  7. Gamma-ray emission spectra from spheres with 14 MeV neutron source

    International Nuclear Information System (INIS)

    Yamamoto, Junji; Kanaoka, Takeshi; Murata, Isao; Takahashi, Akito; Sumita, Kenji

    1989-01-01

    Energy spectra of neutron-induced gamma-rays emitted from spherical samples were measured using a 14 MeV neutron source. The samples in use were LiF, Teflon:(CF 2 ) n , Si, Cr, Mn, Co, Cu, Nb, Mo, W and Pb. A diameter of the sphere was either 40 or 60 cm. The gamma-ray energy in the emission spectra covered the range from 500 keV to 10 MeV. Measured spectra were compared with transport calculations using the nuclear data files of JENDL-3T and ENDF/B-IV. The agreements between the measurements and the JENDL-3T calculations were good in the emission spectra for the low energy gamma-rays from inelastic scattering. (author)

  8. Measurement of the relationship of 24 Na activity and the received neutron dose

    International Nuclear Information System (INIS)

    Gossio, S.; Carrelli, J.; Villella, A.; Soppe, E.

    2013-01-01

    In cases of criticality accidents it is required a fast dosimetric system that allows to evaluate the doses of the personnel involved. The reaction (n,y) with sodium presented in the body ( 23 Na), generates 24 Na, that emits two gamma of 1369KeV and 2754 KeV that can be measured using a whole body counter. The experienced were carried out with the irradiation of 252 Cf of a phantom with a solution of NaCl in water. After the irradiation it was measured the 24 Na activity in the whole body counter, which has a HPGe detector previously calibrated in energy and efficiency. Considering the correction by decay, the quantity of 23 Na presented in the body of an adult and elimination curve of 24 Na, it was established a coefficient of neutronic doses by unity of activity of 24 Na measured in the whole body counter. This method is useful for the retrospective estimation of the doses, as well as to carry out a radiological sorting in case of criticality

  9. Using multi spherical spectrometry for determination of dosimetric characteristics of mixed neutron and gamma radiation fields of fission sources

    International Nuclear Information System (INIS)

    Fyulep, M.; Nikodemova, D.; Grabovtsova, A.; Galan, P.; Trousil, J.

    1977-01-01

    Possibilities of the application of multispherical spectrometry in personnel dosimetry of neutrons (n) and gamma radiation (γ) are considered. Studies were made to elucidate a possibility of using albedo dosemeters to increase the sensitivity of personnel dosemeters. Determined were the dose due to the (n,γ) reaction in a human body, absorbed dose and dose equivalent. The effect of (n,γ) dose on the reading of personnel gamma dosemeter was considered. It is shown that the above effect on the dosemeter readings for frontal irradiation by a broad neutron beam in everyday personnel dosimetry near 252 Cf sources may be neglected. Only in the case of strongly slowed-down fission spectrum the effect of the (n,γ) reaction is considerable. The application of albedo dosemeter is expedient to take into account the corrections of personnel dosemeter readings [ru

  10. Tests of the space gamma spectrometer prototype at the JINR experimental facility with different types of neutron generators

    Science.gov (United States)

    Litvak, M. L.; Vostrukhin, A. A.; Golovin, D. V.; Dubasov, P. V.; Zontikov, A. O.; Kozyrev, A. S.; Krylov, A. R.; Krylov, V. A.; Mitrofanov, I. G.; Mokrousov, M. I.; Repkin, A. N.; Timoshenko, G. N.; Udovichenko, K. V.; Shvetsov, V. N.

    2017-07-01

    The results of the tests of the HPGe gamma spectrometer performed with a planetary soil model and different types of pulse neutron generators are presented. All measurements have been performed at the experimental nuclear planetary science facility (Joint Institute for Nuclear Research) for the physical calibration of active gamma and neutron spectrometers. The aim of the study is to model a space experiment on determining the elemental composition of Martian planetary matter by neutron-induced gamma spectroscopy. The advantages and disadvantages of a gas-filled neutron generator in comparison with a vacuum-tube neutron generator are examined.

  11. Histochemical alternations in the Nissl bodies and ribonucleic acid (RNA) in the spinal, gangalion neurones of gamma irradiated rats

    International Nuclear Information System (INIS)

    Mousa, Tohamy A.; Roushdy, Hamed M.; Raid, Nahed A.; Al-Zahaby, Al-Ahmady S.; Sanad, Samia M.

    1984-01-01

    Four groups of adult male albino rats were subjected to whole body gamma-irradiation at the exposure levels of 200, 400, 600 and 1000 rads and the spinal ganglia were dissected out after different intervals of 3 hr., 1, 3, 5, 7, 10, 15 and 30 days. Nissl bodies and ribonucleic acid were demonstrated histochemically. Gamma irradiation may cause a decrease in RNA synthesis which was reflected in a reduced amount of Nissl substance visible in toluidine blue stained you thick sections of spinal ganglion of gamma irradiated rats and in the total amount of cytoplasmic RNA in pyronin-methyl green stained sections compared with control animals

  12. Measurement of the relationship of {sup 24} Na activity and the received neutron dose; Medicion de la relacion de la actividad de {sup 24}Na y la dosis de neutrones recibida

    Energy Technology Data Exchange (ETDEWEB)

    Gossio, S.; Carrelli, J.; Villella, A.; Soppe, E., E-mail: sgossio@arn.gob.ar [Autoridad Regulatoria Nuclear (ARN), Buenos Aires (Argentina)

    2013-07-01

    In cases of criticality accidents it is required a fast dosimetric system that allows to evaluate the doses of the personnel involved. The reaction (n,y) with sodium presented in the body ({sup 23}Na), generates {sup 24}Na, that emits two gamma of 1369KeV and 2754 KeV that can be measured using a whole body counter. The experienced were carried out with the irradiation of {sup 252} Cf of a phantom with a solution of NaCl in water. After the irradiation it was measured the {sup 24}Na activity in the whole body counter, which has a HPGe detector previously calibrated in energy and efficiency. Considering the correction by decay, the quantity of {sup 23}Na presented in the body of an adult and elimination curve of {sup 24}Na, it was established a coefficient of neutronic doses by unity of activity of {sup 24}Na measured in the whole body counter. This method is useful for the retrospective estimation of the doses, as well as to carry out a radiological sorting in case of criticality.

  13. Dose and dose rate effects of whole-body gamma-irradiation: II. Hematological variables and cytokines

    Science.gov (United States)

    Gridley, D. S.; Pecaut, M. J.; Miller, G. M.; Moyers, M. F.; Nelson, G. A.

    2001-01-01

    The goal of part II of this study was to evaluate the effects of gamma-radiation on circulating blood cells, functional characteristics of splenocytes, and cytokine expression after whole-body irradiation at varying total doses and at low- and high-dose-rates (LDR, HDR). Young adult C57BL/6 mice (n = 75) were irradiated with either 1 cGy/min or 80 cGy/min photons from a 60Co source to cumulative doses of 0.5, 1.5, and 3.0 Gy. The animals were euthanized at 4 days post-exposure for in vitro assays. Significant dose- (but not dose-rate-) dependent decreases were observed in erythrocyte and blood leukocyte counts, hemoglobin, hematocrit, lipopolysaccharide (LPS)-induced 3H-thymidine incorporation, and interleukin-2 (IL-2) secretion by activated spleen cells when compared to sham-irradiated controls (p < 0.05). Basal proliferation of leukocytes in the blood and spleen increased significantly with increasing dose (p < 0.05). Significant dose rate effects were observed only in thrombocyte counts. Plasma levels of transforming growth factor-beta 1 (TGF-beta 1) and splenocyte secretion of tumor necrosis factor-alpha (TNF-alpha) were not affected by either the dose or dose rate of radiation. The data demonstrate that the responses of blood and spleen were largely dependent upon the total dose of radiation employed and that an 80-fold difference in the dose rate was not a significant factor in the great majority of measurements.

  14. Thermal neutron capture cross section for Fe-56(n,gamma)

    Czech Academy of Sciences Publication Activity Database

    Firestone, R. B.; Belgya, T.; Krtička, M.; Bečvář, F.; Szentmiklosi, L.; Tomandl, Ivo

    2017-01-01

    Roč. 95, č. 1 (2017), č. článku 014328. ISSN 2469-9985 R&D Projects: GA ČR GA13-07117S; GA MŠk LM2015056 Institutional support: RVO:61389005 Keywords : neutron cross section * gamma gamma-coincidence data Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders OBOR OECD: Nuclear physics Impact factor: 3.820, year: 2016

  15. 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)

  16. Prenatal exposure to gamma/neutron irradiation: Sensorimotor alterations and paradoxical effects on learning

    International Nuclear Information System (INIS)

    Di Cicco, D.; Antal, S.; Ammassari-Teule, M.

    1991-01-01

    The effects of prenatal exposure on gamma/neutron radiations (0.5 Gy at about the 18th day of fetal life) were studied in a hybrid strain of mice (DBA/Cne males x C57BL/Cne females). During ontogeny, measurements of sensorimotor reflexes revealed in prenatally irradiated mice (1) a delay in sensorial development, (2) deficits in tests involving body motor control, and (3) a reduction of both motility and locomotor activity scores. In adulthood, the behaviour of prenatally irradiated and control mice was examined in the open field test and in reactivity to novelty. Moreover, their learning performance was compared in several situations. The results show that, in the open field test, only rearings were more frequent in irradiated mice. In the presence of a novel object, significant sex x treatment interactions were observed since ambulation and leaning against the novel object increased in irradiated females but decreased in irradiated males. Finally, when submitted to different learning tasks, irradiated mice were impaired in the radial maze, but paradoxically exhibited higher avoidance scores than control mice, possibly because of their low pain thresholds. Taken together, these observations indicate that late prenatal gamma/neutron irradiation induces long lasting alterations at the sensorimotor level which, in turn, can influence learning abilities of adult mice

  17. Study of gamma ray multiplicity spectra for radiative capture of neutrons in 113,115In

    International Nuclear Information System (INIS)

    Georgiev, G.P.; Fajkov-Stanchik, Kh.; Grigor'ev, Yu.V.; Muradyan, G.V.; Yaneva, N.B.

    1997-08-01

    Neutron radiative capture measurements were performed for the enriched isotopes 113 In and 115 In on the neutron spectrometer at the Neutron Physics Laboratory of the Joint Institute for Nuclear Research employing the gamma ray multiplicity technique and using a ''Romashka'' multi-sectional 4p detector on the 500 m time base of the IBR-30 booster. The gamma multiplicity spectra of resolved resonances were obtained for the 20-500 eV energy range. The mean gamma ray multiplicity was determined for each resonance. The dependence of the ratio S of the low-energy coincidence multiplicity spectrum to the high-energy coincidence multiplicity spectrum on resonance energy exhibits a non-statistical structure. This structure was found to correlate with the local neutron strength function. (author). 10 refs, 6 figs, 2 tabs

  18. Self-absorption of neutron capture gamma-rays in gold samples

    International Nuclear Information System (INIS)

    Wisshak, K.; Walter, G.; Kaeppeler, F.

    1983-06-01

    The self absorption of neutron capture gamma rays in gold samples has been determined experimentally for two standard setups used in measurements of neutron capture cross sections. One makes use of an artificially collimated neutron beam and two C 6 D 6 detectors, the other of kinematically collimated neutrons and three Moxon-Rae detectors. Correction factors for an actual measurement of a neutron capture cross section using a gold standard of 1 mm thickness up to 12% were found for the first setup while they are only 4% for the second setup. The present data allow to determine the correction in an actual measurement with an accuracy of 0.5-1%. (orig.) [de

  19. Study of neutron and gamma shielding by lead borate and bismuth lead borate glasses: transparent radiation shielding

    International Nuclear Information System (INIS)

    Singh, Vishwanath P.; Badiger, N.M.

    2013-01-01

    Radiation shielding for gamma and neutron is the prominent area in nuclear reactor technology, medical application, dosimetry and other industries. Shielding of these types of radiation requires an appropriate concrete with mixture of low-to-high Z elements which is an opaque medium. The transparent radiation shielding in visible light for gamma and neutron is also extremely essential in the nuclear facilities as lead window. Presently various types of lead equivalent glass oxides have been invented which are transparent as well as provide protection from radiation. In our study we have assessment of effectiveness of neutron and gamma radiation shielding of xPbO.(1-x) B 2 O 3 (x=0.15 to 0.60) and xBi 2 O 3 .(0.80-x) PbO.0.20 B 2 O 3 (x=0.10 to 0.70) transparent borate and bismuth glasses by NXCOM program. The neutron effective mass removal cross section, Σ R /ρ (cm 2 /g) of the lead, bismuth and boron oxides are given. We found invariable Σ R /ρ of various combinations of the lead borate glass for x=0.15 to 0.60 and bismuth lead borate glass for x=0.10 to 0.70. It is observed that the effective removal cross-section for fast neutron (cm -1 ) of lead borate reduces significantly whereas roughly constant for bismuth borate. The gamma mass attenuation coefficients (μ/ρ) of the glasses were also compared with possible experimental values and found comparable. High (μ/ρ) for gamma radiation of the bismuth glasses shows that it is better gamma shielding compared with lead containing glass. However lead borate glasses are better neutron shielding as the neutron removal coefficient are higher. Our investigation is very useful for nuclear reactor technology where prompt neutron of energy 17 MeV and gamma photon up to 10 MeV produced. (author)

  20. Parameters of a simple whole body counter and thyroid monitor established at the Dresden Felsenkeller underground laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Sahre, P [Rossendorf Nuclear Engineering and Analytics, Inc., Dresden (Germany); Schoenmuth, T [Rossendorf Nuclear Engineering and Analytics, Inc., Dresden (Germany)

    1997-03-01

    At the Rossendorf Nuclear Engineering and Analytics Inc. a simple whole body counter and an iodine-thyroid monitor are used for measuring the internal contamination of workers. There is no shielding chamber in both cases. By using the chamber at the Dresden Felsenkeller underground laboratory the lower limit of detection could be improved by a factor of about 3 for whole body counting and by a factor of 2,5 for thyroid monitoring (I 131, I 125). Concerning the lower limit of detection the applicability of the German standard DIN 25 482 implemented in the Gamma-Vision software packadge is discussed in the paper. (orig.)

  1. Low Dietary Protein Status Potentiating Risk of Health Hazard in Whole Body Gamma Irradiated Rats

    International Nuclear Information System (INIS)

    El-Gawish, M.A.M.; Yousri, R.M.; Roushdy, H.M.; Abdel-Reheem, K.A.; Al-Mossallamy, N.A.

    1998-01-01

    Investigations were planned to assess the changes in certain biochemical parameters as affected by the synergistic effect of exposure to fractionated doses of rays and / or feeding on different protein levels. The date showed that animals kept on normal or low protein diet exhibited a significant decrease in serum total protein and glucose. Also , a significant increase was recorded in insulin level in rats exposed at the radiation dose level of 20 Gy. Exposure to cumulative doses of irradiation has aggrevated the hyperglycemic effect of high protein diet with a significant and marked increase of insulin at all the applied doses. Animals fed normal high or low protein diet were found to exert significant decreases in T3, T4 while a significant increase in TSH of high protein group occurred as a result of exposure to cumulative doses of gamma-irradiation. Rats kept on low protein diet exhibited losses in body weight, hypercholesterolemia, low levels of phospholipids and triglycerides as compared with the normal protein diet group. In contrast high protein diet group showed no serious effects. Irradiation has potentiated body weight losses, hypotriglyceridemia and hypercholesterolemia in animal group fed low protein diet with a significant increase in serum phospholipids due to the higher radiation dose of 20 Gy. Protein deficiency acted synergistically with gamma irradiation and increased the susceptibility of body organs to radiation damage. Such findings contributed to the knowledge which stimulated the decrease of the internationally recognized occupational dose limits from 50 down to 20 m Sv (ICRP 1991)

  2. Thermal neutron detector and gamma-ray spectrometer utilizing a single material

    Science.gov (United States)

    Stowe, Ashley; Burger, Arnold; Lukosi, Eric

    2017-05-02

    A combined thermal neutron detector and gamma-ray spectrometer system, including: a detection medium including a lithium chalcopyrite crystal operable for detecting thermal neutrons in a semiconductor mode and gamma-rays in a scintillator mode; and a photodetector coupled to the detection medium also operable for detecting the gamma rays. Optionally, the detection medium includes a .sup.6LiInSe.sub.2 crystal. Optionally, the detection medium comprises a compound formed by the process of: melting a Group III element; adding a Group I element to the melted Group III element at a rate that allows the Group I and Group III elements to react thereby providing a single phase I-III compound; and adding a Group VI element to the single phase I-III compound and heating; wherein the Group I element includes lithium.

  3. 3D whole body scanners revisited

    NARCIS (Netherlands)

    Daanen, H.A.M.; Haar, F.B. ter

    2013-01-01

    An overview of whole body scanners in 1998 (H.A.M. Daanen, G.J. Van De Water. Whole body scanners, Displays 19 (1998) 111-120) shortly after they emerged to the market revealed that the systems were bulky, slow, expensive and low in resolution. This update shows that new developments in sensing and

  4. Quantitative and qualitative applications of the neutron-gamma borehole logging

    International Nuclear Information System (INIS)

    Charbucinski, J.; Aylmer, J.A.; Eisler, P.L.; Borsaru, M.

    1989-01-01

    Two neutron-γ borehole logging applications are described. In a quantitative application of the prompt-gamma neutron-activation analysis (PGNAA) technique, research was carried out both in the laboratory and at a mine to establish a suitable borehole logging technology for manganese-grade predictions. As an example of the qualitative application of PGNAA, the use of this method has been demonstrated for the determination of lithology. (author)

  5. Angular resolution study of a combined gamma-neutron coded aperture imager for standoff detection

    International Nuclear Information System (INIS)

    Ayaz-Maierhafer, Birsen; Hayward, Jason P.; Ziock, Klaus P.; Blackston, Matthew A.; Fabris, Lorenzo

    2013-01-01

    Nuclear threat source observables at standoff distances of tens of meters from mCi class sources include both gamma-rays and neutrons. This work uses simulations to investigate the effects of the angular resolution of a mobile gamma-ray and neutron coded aperture imaging system upon orphan source detection significance and specificity. The design requires maintaining high sensitivity and specificity while keeping the system size as compact as possible to reduce weight, footprint, and cost. A mixture of inorganic and organic scintillators was considered in the detector plane for high sensitivity to both gamma-rays and fast neutrons. For gamma-rays (100 to 2500 keV) and fission spectrum neutrons, angular resolutions of 1–9° and radiation angles of incidence appropriate for mobile search were evaluated. Detection significance for gamma-rays considers those events that contribute to the photopeak of the image pixel corresponding the orphan source location. For detection of fission spectrum neutrons, energy depositions above a set pulse shape discrimination threshold were tallied. The results show that the expected detection significance for the system at an angular resolution of 1° is significantly lower compared to its detection significance an angular resolution of ∼3–4°. An angular resolution of ∼3–4° is recommended both for better detection significance and improved false alarm rate, considering that finer angular resolution does not result in improved background rejection when the coded aperture method is used. Instead, over-pixelating the search space may result in an unacceptably high false alarm rate

  6. Neutron interrogation system using high gamma ray signature to detect contraband special nuclear materials in cargo

    Science.gov (United States)

    Slaughter, Dennis R [Oakland, CA; Pohl, Bertram A [Berkeley, CA; Dougan, Arden D [San Ramon, CA; Bernstein, Adam [Palo Alto, CA; Prussin, Stanley G [Kensington, CA; Norman, Eric B [Oakland, CA

    2008-04-15

    A system for inspecting cargo for the presence of special nuclear material. The cargo is irradiated with neutrons. The neutrons produce fission products in the special nuclear material which generate gamma rays. The gamma rays are detecting indicating the presence of the special nuclear material.

  7. Trends in X-, gamma and neutron radiographic imaging at IGCAR Kalpakkam

    International Nuclear Information System (INIS)

    Venkatraman, B.; Raghu, N.; Menaka, M.; Anandraj, R.

    2015-01-01

    In the nuclear fuel cycle, right from raw material stage through fabrication and in service inspection upto the retirement of the component, NDE is an indispensable tool. While X- and gamma radiography is quite common, neutron radiography is a very efficient and complementary tool which can enhance investigations in the field of non-destructive testing as well as in many fundamental research applications. The main advantage of neutrons compared to X-rays is its ability to penetrate heavy elements and also image light elements (i.e. with low atomic numbers) such as hydrogen, water, carbon etc. This is because, neutrons interact with the nucleus rather than with the outer electron in the shell. This also makes it possible to distinguish between different isotopes of the same element by neutron radiography. The KAMINI reactor at IGCAR is a versatile and unique facility wherein extensive work has been undertaken on neutron radiography and activation analysis. Apart from conventional neutron radiography using transfer technique, real time neutron imaging of fuel pins and other objects have also been carried out. Using Beam purity indicator and sensitivity indicator, the neutron beam from KAMINI has also been characterized. This paper focuses on the developments and applications of digital imaging NDE using X-, gamma and neutrons at IGCAR. Both 2-dimensional imaging and -D tomography has been undertaken. Case studies undertaken for strategic and core industries including societal applications such as in cultural heritage is also highlighted. Advanced image processing and analysis has also been applied for enhancing the sensitivity and better defect quantification

  8. Measurement of neutron and gamma-ray production double differential cross section at KEK

    International Nuclear Information System (INIS)

    Ishibashi, Kenji

    1995-01-01

    High energy nuclear radiations were measured for 0.8-3.0 GeV proton induced reactions at KEK. The measurement was carried out to overcome the problems arising from the use of secondary beam line of a quite low incident beam intensity. Digital pulse shape discrimination method was applicable to separation between high energy neutrons and gamma-rays. By the use of a number of scintillators, cross sections were obtained for production of neutrons and gamma-rays. (author)

  9. Effect of intestinal microflora on the survival time of mice exposed to lethal whole-body. gamma. irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Onoue, M.; Uchida, K.; Yokokura, T.; Takahashi, T.; Mutai, M.

    1981-11-01

    The effect of intestinal microflora on the survival time of mice exposed to 2-kR whole-body ..gamma.. irradiation was studied using germfree, monoassociated, and conventionalized ICR mice. The germfree mice were monoassociated with 1 of 11 bacterial strains, which were isolated from the fresh feces of conventional mice, 2 weeks prior to irradiation. All mice died within 3 weeks after irradiation. Monoassociation with Fusobacterium sp., Streptococcus faecalis, Escherichia coli, or Pseudomonas sp. significantly reduced the mean survival time compared to that of germfree mice. In contrast, monoassociation with Clostridium sp., Bifidobacterium pseudolongum, or Lactobacillus acidophilus significantly prolonged the mean survival time compared to that of germfree mice. This suggests that the latter organisms may perform some activity to protect the mice from radiation injury. In this histopathological autopsy examination, the main lesions were hypocellularity in hematopoietic organs and hemorrhage in various organs. Neither karyorrhexis nor desquamation of intestinal mucosal cells was observed in any mice. From these observations, it is suggested that the death of these mice was related to hematopoietic damage. Bacterial invasion into various organs was observed in conventionalized and Pseudomonas-, E. coli-, or S. faecalis-monoassociated mice but not in Clostridium-, B. pseudolongum-, L. acidophilus-, or Fusobacterium-monoassociated mice.

  10. Prompt gamma cold neutron activation analysis applied to biological materials

    International Nuclear Information System (INIS)

    Rossbach, M.; Hiep, N.T.

    1992-01-01

    Cold neutrons at the external neutron guide laboratory (ELLA) of the KFA Juelich are used to demonstrate their profitable application for multielement characterization of biological materials. The set-up and experimental conditions of the Prompt Gamma Cold Neutron Activation Analysis (PGCNAA) device is described in detail. Results for C, H, N, S, K, B, and Cd using synthetic standards and the 'ratio' technique for calculation are reported for several reference materials and prove the method to be reliable and complementary with respect to the elements being determined by INAA. (orig.)

  11. {gamma}-Ray background sources in the VESUVIO spectrometer at ISIS spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Pietropaolo, A. [CNISM Milano-Bicocca, Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G. Occhialini' , Piazza della Scienza 3, 20126 Milano (Italy); NAST Center (Nanoscienze-Nanotecnologie-Strumentazione), Universita degli Studi di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma (Italy)], E-mail: antonino.pietropaolo@mib.infn.it; Perelli Cippo, E. [Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G. Occhialini' , Piazza della Scienza 3, 20126 Milano (Italy); Gorini, G. [CNISM Milano-Bicocca, Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G. Occhialini' , Piazza della Scienza 3, 20126 Milano (Italy); NAST Center (Nanoscienze-Nanotecnologie-Strumentazione), Universita degli Studi di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma (Italy); Tardocchi, M. [Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G. Occhialini' , Piazza della Scienza 3, 20126 Milano (Italy); Schooneveld, E.M. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire 0QX OX11 (United Kingdom); Andreani, C.; Senesi, R. [Universia degli Studi di Roma Tor Vergata, Dipartimento di Fisica and NAST Center (Nanoscienze-Nanotecnologie-Strumentazione), via della Ricerca Scientifica 1, 00133 Roma (Italy)

    2009-09-01

    An investigation of the gamma background was carried out in the VESUVIO spectrometer at the ISIS spallation neutron source. This study, performed with a yttrium-aluminum-perovskite (YAP) scintillator, follows high resolution pulse height measurements of the gamma background carried out on the same instrument with the use of a high-purity germanium detector. In this experimental work, a mapping of the gamma background was attempted, trying to find the spatial distribution and degree of directionality of the different contributions identified in the previous study. It is found that the gamma background at low times is highly directional and mostly due to the gamma rays generated in the moderator-decoupler system. The other contributions, consistently to the findings of a previous experiment, are identified as a nearly isotropic one due to neutron absorption in the walls of the experimental hall, and a directional one coming from the beam dump.

  12. Improving the safety of a body composition analyser based on the PGNAA method

    Energy Technology Data Exchange (ETDEWEB)

    Miri-Hakimabad, Hashem; Izadi-Najafabadi, Reza; Vejdani-Noghreiyan, Alireza; Panjeh, Hamed [FUM Radiation Detection And Measurement Laboratory, Ferdowsi University of Mashhad (Iran, Islamic Republic of)

    2007-12-15

    The {sup 252}Cf radioisotope and {sup 241}Am-Be are intense neutron emitters that are readily encapsulated in compact, portable and sealed sources. Some features such as high flux of neutron emission and reliable neutron spectrum of these sources make them suitable for the prompt gamma neutron activation analysis (PGNAA) method. The PGNAA method can be used in medicine for neutron radiography and body chemical composition analysis. {sup 252}Cf and {sup 241}Am-Be sources generate not only neutrons but also are intense gamma emitters. Furthermore, the sample in medical treatments is a human body, so it may be exposed to the bombardments of these gamma-rays. Moreover, accumulations of these high-rate gamma-rays in the detector volume cause simultaneous pulses that can be piled up and distort the spectra in the region of interest (ROI). In order to remove these disadvantages in a practical way without being concerned about losing the thermal neutron flux, a gamma-ray filter made of Pb must be employed. The paper suggests a relatively safe body chemical composition analyser (BCCA) machine that uses a spherical Pb shield, enclosing the neutron source. Gamma-ray shielding effects and the optimum radius of the spherical Pb shield have been investigated, using the MCNP-4C code, and compared with the unfiltered case, the bare source. Finally, experimental results demonstrate that an optimised gamma-ray shield for the neutron source in a BCCA can reduce effectively the risk of exposure to the {sup 252}Cf and {sup 241}Am-Be sources.

  13. Benefits of whole body vibration training in patients hospitalised for COPD exacerbations - a randomized clinical trial.

    Science.gov (United States)

    Greulich, Timm; Nell, Christoph; Koepke, Janine; Fechtel, Juliane; Franke, Maja; Schmeck, Bernd; Haid, Daniel; Apelt, Sandra; Filipovic, Silke; Kenn, Klaus; Janciauskiene, Sabina; Vogelmeier, Claus; Koczulla, Andreas Rembert

    2014-04-11

    Patients with stable COPD show improvements in exercise capacity and muscular function after the application of whole body vibration. We aimed to evaluate whether this modality added to conventional physiotherapy in exacerbated hospitalised COPD patients would be safe and would improve exercise capacity and quality of life. 49 hospitalised exacerbated COPD patients were randomized (1:1) to undergo physiotherapy alone or physiotherapy with the addition of whole body vibration. The primary endpoint was the between-group difference of the 6-minute walking test (day of discharge - day of admission). Secondary assessments included chair rising test, quality of life, and serum marker analysis. Whole body vibration did not cause procedure-related adverse events. Compared to physiotherapy alone, it led to significantly stronger improvements in 6-minute walking test (95.55 ± 76.29 m vs. 6.13 ± 81.65 m; p = 0.007) and St. Georges Respiratory Questionnaire (-6.43 ± 14.25 vs. 5.59 ± 19.15, p = 0.049). Whole body vibration increased the expression of the transcription factor peroxisome proliferator receptor gamma coactivator-1-α and serum levels of irisin, while it decreased serum interleukin-8. Whole body vibration during hospitalised exacerbations did not cause procedure-related adverse events and induced clinically significant benefits regarding exercise capacity and health-related quality of life that were associated with increased serum levels of irisin, a marker of muscle activity. German Clinical Trials Register DRKS00005979. Registered 17 March 2014.

  14. Study of SMM flares in gamma-rays and neutrons

    Science.gov (United States)

    Dunphy, Philip P.; Chupp, Edward L.

    1992-01-01

    This report summarizes the results of the research supported by NASA grant NAGW-2755 and lists the papers and publications produced through the grant. The objective of the work was to study solar flares that produced observable signals from high-energy (greater than 10 MeV) gamma-rays and neutrons in the Solar Maximum Mission (SMM) Gamma-Ray Spectrometer (GRS). In 3 of 4 flares that had been studied previously, most of the neutrons and neutral pions appear to have been produced after the 'main' impulsive phase as determined from hard x-rays and gamma-rays. We, therefore, proposed to analyze the timing of the high-energy radiation, and its implications for the acceleration, trapping, and transport of flare particles. It was equally important to characterize the spectral shapes of the interacting energetic electrons and protons - another key factor in constraining possible particle acceleration mechanisms. In section 2.0, we discuss the goals of the research. In section 3.0, we summarize the results of the research. In section 4.0, we list the papers and publications produced under the grant. Preprints or reprints of the publications are attached as appendices.

  15. Neutron flux measurement utilizing Campbell technique

    International Nuclear Information System (INIS)

    Kropik, M.

    2000-01-01

    Application of the Campbell technique for the neutron flux measurement is described in the contribution. This technique utilizes the AC component (noise) of a neutron chamber signal rather than a usually used DC component. The Campbell theorem, originally discovered to describe noise behaviour of valves, explains that the root mean square of the AC component of the chamber signal is proportional to the neutron flux (reactor power). The quadratic dependence of the reactor power on the root mean square value usually permits to accomplish the whole current power range of the neutron flux measurement by only one channel. Further advantage of the Campbell technique is that large pulses of the response to neutrons are favoured over small pulses of the response to gamma rays in the ratio of their mean square charge transfer and thus, the Campbell technique provides an excellent gamma rays discrimination in the current operational range of a neutron chamber. The neutron flux measurement channel using state of the art components was designed and put into operation. Its linearity, accuracy, dynamic range, time response and gamma discrimination were tested on the VR-1 nuclear reactor in Prague, and behaviour under high neutron flux (accident conditions) was tested on the TRIGA nuclear reactor in Vienna. (author)

  16. Radiography apparatus using gamma rays emitted by water activated by fusion neutrons

    Science.gov (United States)

    Smith, Donald L.; Ikeda, Yujiro; Uno, Yoshitomo

    1996-01-01

    Radiography apparatus includes an arrangement for circulating pure water continuously between a location adjacent a source of energetic neutrons, such as a tritium target irradiated by a deuteron beam, and a remote location where radiographic analysis is conducted. Oxygen in the pure water is activated via the .sup.16 O(n,p).sup.16 N reaction using .sup.14 -MeV neutrons produced at the neutron source via the .sup.3 H(d,n).sup.4 He reaction. Essentially monoenergetic gamma rays at 6.129 (predominantly) and 7.115 MeV are produced by the 7.13-second .sup.16 N decay for use in radiographic analysis. The gamma rays have substantial penetrating power and are useful in determining the thickness of materials and elemental compositions, particularly for metals and high-atomic number materials. The characteristic decay half life of 7.13 seconds of the activated oxygen is sufficient to permit gamma ray generation at a remote location where the activated water is transported, while not presenting a chemical or radioactivity hazard because the radioactivity falls to negligible levels after 1-2 minutes.

  17. Toward whole-core neutron transport without spatial homogenization

    International Nuclear Information System (INIS)

    Lewis, E. E.

    2009-01-01

    Full text of publication follows: A long-term goal of computational reactor physics is the deterministic analysis of power reactor core neutronics without incurring significant discretization errors in the energy, spatial or angular variables. In principle, given large enough parallel configurations with unlimited CPU time and memory, this goal could be achieved using existing three-dimensional neutron transport codes. In practice, however, solving the Boltzmann equation for neutrons over the six-dimensional phase space is made intractable by the nature of neutron cross-sections and the complexity and size of power reactor cores. Tens of thousands of energy groups would be required for faithful cross section representation. Likewise, the numerous material interfaces present in power reactor lattices require exceedingly fine spatial mesh structures; these ubiquitous interfaces preclude effective implementation of adaptive grid, mesh-less methods and related techniques that have been applied so successfully in other areas of engineering science. These challenges notwithstanding, substantial progress continues in the pursuit for more robust deterministic methods for whole-core neutronics analysis. This paper examines the progress over roughly the last decade, emphasizing the space-angle variables and the quest to eliminate errors attributable to spatial homogenization. As prolog we briefly assess 1990's methods used in light water reactor analysis and review the lessons learned from the C5G7 benchmark exercises which were originated in 1999 to appraise the ability of transport codes to perform core calculations without homogenization. We proceed by examining progress over the last decade much of which falls into three areas. These may be broadly characterized as reduced homogenization, dynamic homogenization and planar-axial synthesis. In the first, homogenization in three-dimensional calculations is reduced from the fuel assembly to the pin-cell level. In the second

  18. Investigation of dose distribution in mixed neutron-gamma field of boron neutron capture therapy using N isopropylacrylamide gel

    Energy Technology Data Exchange (ETDEWEB)

    Bavarmegin, Elham; Sadremomtaz, Alireza [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of); Khalafi, Hossein; Kasesaz, Yaser [Dept. of Physics, University of Guilan, Rasht (Iran, Islamic Republic of); Khajeali, Azim [Medical Education Research Center, Tabriz (Iran, Islamic Republic of)

    2017-02-15

    Gel dosimeters have unique advantages in comparison with other dosimeters. Until now, these gels have been used in different radiotherapy techniques as a reliable dosimetric tool. Because dose distribution measurement is an important factor for appropriate treatment planning in different radiotherapy techniques, in this study, we evaluated the ability of the N-isopropylacrylamide (NIPAM) polymer gel to record the dose distribution resulting from the mixed neutron-gamma field of boron neutron capture therapy (BNCT). In this regard, a head phantom containing NIPAM gel was irradiated using the Tehran Research Reactor BNCT beam line, and then by a magnetic resonance scanner. Eventually, the R2 maps were obtained in different slices of the phantom by analyzing T2-weighted images. The results show that NIPAM gel has a suitable potential for recording three-dimensional dose distribution in mixed neutron-gamma field dosimetry.

  19. Use of neutron capture gamma radiation for determining grade of iron ore in blast holes and exploration holes

    International Nuclear Information System (INIS)

    Eisler, P.L.; Huppert, P.; Mathew, P.J.; Wylie, A.W.; Youl, S.F.

    1977-01-01

    Neutron radiative capture and neutron-neutron logging have been applied to determining the grade of ore in dry blast holes and a dry exploration hole drilled into a layered iron deposit. Both thermal and epithermal neutron responses were measured as well as the gamma-ray responses due to neutron capture by iron and by hydrogen present in hydrated minerals. The results were fitted by a stepwise multiple linear regression technique to give expressions for mean grade of ore in the drill hole and 95% confidence intervals for estimation of this mean. For an overall range of ore grades of 20-68% Fe and a mean grade of 63% Fe, the confidence interval for prediction of mean grade for the neutron-gamma technique was 0.3% Fe for pooled data from all five blast holes and 0.8% Fe for a single hole. It was also shown that for this type of layered deposit a simpler neutron-neutron log incorporating simultaneous measurement of both thermal and epithermal neutron responses gave almost as good a grade prediction result for pooled results from five drill holes, namely 63+-0.4% Fe, as that obtained by the neutron-gamma technique. The results of both types of log are compared with those obtained by the spectral gamma-ray backscattering [Psub(z)] technique, or by logging of natural gamma radiations from the shale component of the ore. From this comparison conclusions are drawn regarding the most suitable technique to employ for determining grade of iron ore in various practical logging situations. (author)

  20. Calculation of neutron and gamma-ray energy spectra in liquid air and liquid nitrogen due to 14-MeV neutron and californium-252 sources

    International Nuclear Information System (INIS)

    Straker, E.A.; Gritzner, M.L.; Harris, L. Jr.

    1978-01-01

    Calculations of neutron and gamma-ray fluences from 14-MeV neutron and 252 Cf sources in liquid air and liquid nitrogen have been performed. These calculations were made specifically for comparison with experimental data measured at Stohl, Federal Republic of Germany. The discrete-ordinates method was utilized with neutron and gamma-ray cross sections from ENDF/B-IV. One-dimensional calculational models were developed for the sources and tank. Limited comparisons are made with experimental data

  1. Neutron-Activated Gamma-Emission: Technology Review

    Science.gov (United States)

    2012-01-01

    in Be9 + α  C12 + n and Be9 + α  3He4 + n. Chadwick (5) made use of the naturally occurring α-emitter polonium - 210 , which decays to lead-206 with...emission, the variation of gamma attenuation with distance and the presence of organic clutter (in food , fertilizer, dirt road, etc.) makes it 8...a neutron source by mixing a radioisotope that emits alpha particles, such as radium or polonium , with a low atomic weight isotope, usually in the

  2. Design of a facility by neutron activation by spectrometry of prompt gamma

    International Nuclear Information System (INIS)

    Oliver, R.; Benites L, S.; Montoya Z, M.

    1993-01-01

    We show the basic design of the facility of PGNAA that we will install in the hall of the peruvian reactor RP-10. The thermal neutron flux (without a gamma filter) will be 2,0 x 10 8 n/cm -2 s -1 at 10 MW of power. The ratio of gamma exposition without gamma filter will be 29 kR/h. (authors). 8 refs., 2 figs

  3. Studying the shielding properties of lead glass composites using neutrons and gamma rays

    International Nuclear Information System (INIS)

    Osman, A.M.; El-Sarraf, M.A.; Abdel-Monem, A.M.; El-Sayed Abdo, A.

    2015-01-01

    Highlights: • Samples of sodalime silica glass loaded with different ratios of PbO were prepared. • Leaded glass composites were investigated for radiation shielding. • Experimental and theoretical attenuation parameters were studied. • Experimental and theoretical (MCNP5) results were in good agreement. - Abstract: The present work deals with the shielding properties of lead glass composites to find out its integrity for practical shielding applications and radiological safety. Composites of different lead oxide ratios (x = 0, 5, 10, 15 and 25 wt.%) have been prepared by the Nasser Glass and Crystal Company (Egypt). Attenuation measurements have been carried out using a collimated emitted beam from a fission 252 Cf (100 μg) neutron source, and the neutron–gamma spectrometer with stilbene scintillator. The pulse shape discriminating (P.S.D.) technique based on the zero cross-over method was used to discriminate between neutron and gamma-ray pulses. Thermal neutron fluxes were measured using the BF3 detector and thermal neutron detection system. The attenuation relations were used to evaluate fast neutron macroscopic effective removal cross-section Σ R-Meas (cm −1 ), gamma rays total attenuation coefficient μ (cm −1 ) and thermal neutron macroscopic cross-section Σ Meas (cm −1 ). Theoretical calculations have been achieved using MCNP5 code to calculate the same two parameters. Also, MERCSF-N program was used to calculate fast neutron macroscopic removal cross-section Σ R-MER (cm −1 ). Measured and MCNP5 calculated results have been compared and were found to be in reasonable agreement

  4. MCNP modelling of a combined neutron/gamma counter

    CERN Document Server

    Bourva, L C A; Ottmar, H; Weaver, D R

    1999-01-01

    A series of Monte Carlo neutron calculations for a combined gamma/passive neutron coincidence counter has been performed. This type of device, part of a suite of non-destructive assay instruments utilised for the enforcement of the Euratom nuclear safeguards within the European Union, is to be used for high accuracy measurements of the plutonium content of small samples of nuclear materials. The multi-purpose Monte Carlo N-particle (MCNP) code version 4B has been used to model in detail the neutron coincidence detector and to investigate the leakage self-multiplication of PuO sub 2 and mixed U-Pu oxide (MOX) reference samples used to calibrate the instrument. The MCNP calculations have been used together with a neutron coincidence counting interpretative model to determine characteristic parameters of the detector. A comparative study to both experimental and previous numerical results has been performed. Sensitivity curves of the variation of the detector's efficiency, epsilon, to, alpha, the ratio of (alpha...

  5. Measuring planetary neutron albedo fluxes by remote gamma-ray sensing

    International Nuclear Information System (INIS)

    Haines, E.L.; Metzger, A.E.

    1984-01-01

    A remote-sensing γ-ray spectrometer (GRS) is capable of measuring planetary surface composition through the detection of characteristic gamma rays. In addition, the planetary neutron leakage flux may be detected by means of a thin neutron absorber surrounding the γ-ray detector which converts the neutron flux into a γ-ray flux having a unique energy signature. The γ rays representing the neutron flux are observed against interference consisting of cosmic γ rays, planetary continuum and line emission, and a variety of gamma rays arising from cosmic-ray particle interactions with the γ-ray spectrometer and spacecraft (SC). In this paper the amplitudes of planetary and non-planetary neutron fluxes are assessed and their impact on the sensitivity of measurement is calculated for a lunar orbiter mission and a comet nucleus rendezvous mission. For a 100 h observation period from an altitude of 100 km, a GRS on a lunar orbiter can detect a thermal neutron albedo flux as low as 0.002 cm -2 s -1 and measure the expected flux of approx.=0.6 cm -2 s -1 with an uncertainty of 0.001 cm -2 s -1 . A GRS rendezvousing with a comet at a distance equal to the radius of the comet's nucleus, again for a 100 h observation time, should detect a thermal neutron albedo flux at a level of 0.006 cm -2 s -1 and measure the expected flux of approx.=0.4 cm -2 s -1 with an uncertainty of 0.004 cm -2 s -1 . Mapping the planetary neutron flux jointly with the direct detection of H will not only provide a more accurate model for translating observed γ-ray fluxes into concentrations but will also extend the effective sampling depth and should provide a capability for simple stratigraphic modeling of hydrogen. (orig.)

  6. Gamma ray generator

    Science.gov (United States)

    Firestone, Richard B; Reijonen, Jani

    2014-05-27

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

  7. Calculation of gamma-rays and fast neutrons fluxes with the program Mercure-4

    International Nuclear Information System (INIS)

    Baur, A.; Dupont, C.; Totth, B.

    1978-01-01

    The program MERCURE-4 evaluates gamma ray or fast neutron attenuation, through laminated or bulky three-dimensionnal shields. The method used is that of line of sight point attenuation kernel, the scattered rays being taken into account by means of build-up factors for γ and removal cross sections for fast neutrons. The integration of the point kernel over the range of sources distributed in space and energy, is performed by the Monte-Carlo method, with an automatic adjustment of the importance functions. Since it is operationnal the program MERCURE-4 has been intensively used for many various problems, for example: - the calculation of gamma heating in reactor cores, control rods and shielding screens, as well as in experimental devices and irradiation loops; - the evaluation of fast neutron fluxes and corresponding damage in structural materials of reactors (vessel steels...); - the estimation of gamma dose rates on nuclear instrumentation in the reactors, around the reactor circuits and around spent fuel shipping casks

  8. Evaluation of neutron and gamma-ray-production cross-section data for lead

    International Nuclear Information System (INIS)

    Fu, C.Y.; Perey, F.G.

    1975-01-01

    A survey was made of the available information on neutron and gamma-ray-production cross-section measurements of lead. From these and from relevant nuclear-structure information on the Pb isotopes, recommended neutron cross-section data sets for lead covering the neutron energy range from 0.00001 eV to 20.0 MeV have been prepared. The cross sections are derived from experimental results available to February 1972 and from calculations based on optical-model, DWBA, and Hauser--Feshbach theories. Comparisons which show good agreement between theoretical and experimental values are displayed in a number of graphs. Also presented graphically are smoothed total cross sections, Legendre coefficients for angular distributions, and a representative energy distribution of gamma rays from resonance capture. 15 tables, 36 figures, 104 references

  9. Quantification of interstitial fluid on whole body CT: comparison with whole body autopsy.

    Science.gov (United States)

    Lo Gullo, Roberto; Mishra, Shelly; Lira, Diego A; Padole, Atul; Otrakji, Alexi; Khawaja, Ranish Deedar Ali; Pourjabbar, Sarvenaz; Singh, Sarabjeet; Shepard, Jo-Anne O; Digumarthy, Subba R; Kalra, Mannudeep K; Stone, James R

    2015-12-01

    Interstitial fluid accumulation can occur in pleural, pericardial, and peritoneal spaces, and subcutaneous tissue planes. The purpose of the study was to assess if whole body CT examination in a postmortem setting could help determine the presence and severity of third space fluid accumulation in the body. Our study included 41 human cadavers (mean age 61 years, 25 males and 16 females) who had whole-body postmortem CT prior to autopsy. All bodies were maintained in the morgue in the time interval between death and autopsy. Two radiologists reviewed the whole-body CT examinations independently to grade third space fluid in the pleura, pericardium, peritoneum, and subcutaneous space using a 5-point grading system. Qualitative CT grading for third space fluid was correlated with the amount of fluid found on autopsy and the quantitative CT fluid volume, estimated using a dedicated software program (Volume, Syngo Explorer, Siemens Healthcare). Moderate and severe peripheral edema was seen in 16/41 and 7/41 cadavers respectively. It is not possible to quantify anasarca at autopsy. Correlation between imaging data for third space fluid and the quantity of fluid found during autopsy was 0.83 for pleural effusion, 0.4 for pericardial effusion and 0.9 for ascites. The degree of anasarca was significantly correlated with the severity of ascites (p < 0.0001) but not with pleural or pericardial effusion. There was strong correlation between volumetric estimation and qualitative grading for anasarca (p < 0.0001) and pleural effusion (p < 0.0001). Postmortem CT can help in accurate detection and quantification of third space fluid accumulation. The quantity of ascitic fluid on postmortem CT can predict the extent of anasarca.

  10. 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.

  11. The effect of pulse pile-up on discrimination between neutrons and gamma rays

    International Nuclear Information System (INIS)

    Whittlestone, S.

    1980-01-01

    Pulse pile-up lengthens the rise-time of pulses. With an organic scintillator such as NE 213, pile-up can cause a short rise-time pulse originating from gamma rays to be interpreted by a rise-time analyser as a neutron. The degradation of pulse shape analyser performance at high count rates is shown to be directly related to pulse pile-up. Using this relationship, the contribution of piled-up gamma rays and neutrons to count rate related errors is calculated for a time-dependent fast neutron energy spectrum measurement. Errors of a few per cent occur even when the probability of a count per burst is as low as 0.01. (orig.)

  12. Use of borated polyethylene to improve low energy response of a prompt gamma based neutron dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Priyada, P.; Ashwini, U.; Sarkar, P.K., E-mail: pradip.sarkar@manipal.edu

    2016-05-21

    The feasibility of using a combined sample of borated polyethylene and normal polyethylene to estimate neutron ambient dose equivalent from measured prompt gamma emissions is investigated theoretically to demonstrate improvements in low energy neutron dose response compared to only polyethylene. Monte Carlo simulations have been carried out using the FLUKA code to calculate the response of boron, hydrogen and carbon prompt gamma emissions to mono energetic neutrons. The weighted least square method is employed to arrive at the best linear combination of these responses that approximates the ICRP fluence to dose conversion coefficients well in the energy range of 10{sup −8} MeV to 14 MeV. The configuration of the combined system is optimized through FLUKA simulations. The proposed method is validated theoretically with five different workplace neutron spectra with satisfactory outcome. - Highlights: • An improved method is proposed for estimating H⁎(10) using prompt gamma emissions. • A combination of BHDPE and HDPE cylinders is used as a sample. • Linear combination of prompt gamma intensities approximates ICRP-DCC closely. • Feasibility of the method was tested theoretically using workplace neutron spectra.

  13. C-fos protein expression in central nervous system. Effects of acute whole-body irradiation

    International Nuclear Information System (INIS)

    Martin, C.; Chollat, S.; Mahfoudi, H.; Lambert, F.; Baille Le Crom, V.; Fatome, M.

    1995-01-01

    Study of c-Fos protein expression in the rat striatum after gamma or (neutron-gamma) irradiation was carried on. c-Fos protein is expressed one hour after gamma exposure at the dose of 15 Gy but specificity of the response must be verified. (author)

  14. 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

  15. Measurements of the gamma-quanta angular distributions emitted from neutron inelastic scattering on 28Si

    Science.gov (United States)

    Fedorov, N. A.; Grozdanov, D. N.; Bystritskiy, V. M.; Kopach, Yu. N.; Ruskov, I. N.; Skoy, V. R.; Tretyakova, T. Yu.; Zamyatin, N. I.; Wang, D.; Aliev, F. A.; Hramco, C.; Gandhi, A.; Kumar, A.; Dabylova, S.; Bogolubov, E. P.; Barmakov, Yu. N.

    2018-04-01

    The characteristic gamma radiation from the interaction of 14.1 MeV neutrons with a natural silicon sample is investigated with Tagged Neutron Method (TNM). The anisotropy of gamma-ray emission of 1.779 MeV was measured at 11 azimuth angles with a step of ∠15°. The present results are in good agreement with some recent experimental data.

  16. The Prompt Gamma Neutron Activation Analysis Facility at ICN-Pitesti

    International Nuclear Information System (INIS)

    Barbos, D.; Paunoiu, C.; Mladin, M.; Cosma, C.

    2008-01-01

    PGNAA is a very widely applicable technique for determining the presence and amount of many elements simultaneously in samples ranging in size from micrograms to many grams. PGNAA is characterized by its capability for nondestructive multi-elemental analysis and its ability to analyse elements that cannot be determined by INAA. By means of this PGNAA method we are able to increase the performance of INAA method. A facility has been developed at Institute for Nuclear Research-Pitesti so that the unique features of prompt gamma-ray neutron activation analysis can be used to measure trace and major elements in samples. The facility is linked at the radial neutron beam tube at ACPR-TRIGA reactor. During the PGNAA-facility is in use the ACPR reactor will be operated in steady-state mode at 250 KW maximum power. The facility consists of a radial beam-port, external sample position with shielding, and induced prompt gamma-ray counting system.Thermal neutron flux with energy lower than cadmium cut-off at the sample position was measured using thin gold foil is: φ scd = 1.10 6 n/cm 2 /s with a cadmium ratio of:80.The gamma-ray detection system consist of an HpGe detector of 16% efficiency (detector model GC1518) with 1.85 keV resolution capability. The HpGe is mounted with its axis at 90 deg. with respect to the incident neutron beam at distance about 200mm from the sample position. To establish the performance capabilities of the facility, irradiation of pure element or sample compound standards were performed to identify the gama-ray energies from each element and their count rates

  17. The comparison of four neutron sources for Prompt Gamma Neutron Activation Analysis (PGNAA) in vivo detections of boron.

    Science.gov (United States)

    Fantidis, J G; Nicolaou, G E; Potolias, C; Vordos, N; Bandekas, D V

    A Prompt Gamma Ray Neutron Activation Analysis (PGNAA) system, incorporating an isotopic neutron source has been simulated using the MCNPX Monte Carlo code. In order to improve the signal to noise ratio different collimators and a filter were placed between the neutron source and the object. The effect of the positioning of the neutron beam and the detector relative to the object has been studied. In this work the optimisation procedure is demonstrated for boron. Monte Carlo calculations were carried out to compare the performance of the proposed PGNAA system using four different neutron sources ( 241 Am/Be, 252 Cf, 241 Am/B, and DT neutron generator). Among the different systems the 252 Cf neutron based PGNAA system has the best performance.

  18. Non destructive multi elemental analysis using prompt gamma neutron activation analysis techniques: Preliminary results for concrete sample

    Energy Technology Data Exchange (ETDEWEB)

    Dahing, Lahasen Normanshah [School of Applied Physics, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia and Malaysian Nuclear Agency (Nuklear Malaysia), Bangi 43000, Kajang (Malaysia); Yahya, Redzuan [School of Applied Physics, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Yahya, Roslan; Hassan, Hearie [Malaysian Nuclear Agency (Nuklear Malaysia), Bangi 43000, Kajang (Malaysia)

    2014-09-03

    In this study, principle of prompt gamma neutron activation analysis has been used as a technique to determine the elements in the sample. The system consists of collimated isotopic neutron source, Cf-252 with HPGe detector and Multichannel Analysis (MCA). Concrete with size of 10×10×10 cm{sup 3} and 15×15×15 cm{sup 3} were analysed as sample. When neutrons enter and interact with elements in the concrete, the neutron capture reaction will occur and produce characteristic prompt gamma ray of the elements. The preliminary result of this study demonstrate the major element in the concrete was determined such as Si, Mg, Ca, Al, Fe and H as well as others element, such as Cl by analysis the gamma ray lines respectively. The results obtained were compared with NAA and XRF techniques as a part of reference and validation. The potential and the capability of neutron induced prompt gamma as tool for multi elemental analysis qualitatively to identify the elements present in the concrete sample discussed.

  19. Semiconductor dosimetry system for gamma and neutron radiation

    International Nuclear Information System (INIS)

    Savic, Z.; Pavlovic, Z.

    1995-01-01

    The semiconductor dosimetry system for gamma and neutron radiation based on pMOS transistor and PIN diode is described. It is intended for tactical or accidental personal dosimetry. The production steps are given. The temperature, dose and time (fading) response are reported. Hardware and software requirements which are needed for obtaining the desired measurement error are pointed. (author)

  20. Gamma-Free Neutron Detector Based upon Lithium Phosphate Nanoparticles

    International Nuclear Information System (INIS)

    Steven Wallace

    2007-01-01

    A gamma-free neutron-sensitive scintillator is needed to enhance radiation sensing and detection for nonproliferation applications. Such a scintillator would allow very large detectors to be placed at the perimeter of spent-fuel storage facilities at commercial nuclear power plants, so that any movement of spontaneously emitted neutrons from spent nuclear fuel or weapons grade plutonium would be noted in real-time. This task is to demonstrate that the technology for manufacturing large panels of fluor-doped plastic containing lithium-6 phosphate nanoparticles can be achieved. In order to detect neutrons, the nanoparticles must be sufficiently small so that the plastic remains transparent. In this way, the triton and alpha particles generated by the capture of the neutron will result in a photon burst that can be coupled to a wavelength shifting fiber (WLS) producing an optical signal of about ten nanoseconds duration signaling the presence of a neutron emitting source

  1. Possibilities of whole-body MRI for investigating musculoskeletal diseases

    International Nuclear Information System (INIS)

    Lenk, S.; Claussen, C.D.; Schlemmer, H.P.; Fischer, S.; Koetter, I.

    2004-01-01

    This contribution outlines possibilities and limitations of whole-body MRI for investigating musculoskeletal diseases. Benefits and drawbacks of the novel whole-body MRI technology are discussed and a possible whole-body MRI sequence protocol for musculoskeletal examinations is proposed. Muscle, joint and bone diseases are discussed in which the application of whole-body MRI may be of advantage. Particularly, polymyositis, muscledystrophy, rheumatoid arthritis, spondylitis ancylosans, multiple trauma, skeletal metastases, multiple myeloma and malignant lymphoma are mentioned. Whole-body MRI opens new advantages for the examination of multifocal musculoskeletal diseases. The clinical benefit of this method for particular diseases has to be evaluated in further studies, however. (orig.) [de

  2. The generation, validation and testing of a coupled 219-group neutron 36-group gamma ray AMPX-II library

    International Nuclear Information System (INIS)

    Panini, G.C.; Siciliano, F.; Lioi, A.

    1987-01-01

    The main characteristics of a P 3 coupled 219-group neutron 36-group gamma-ray library in the AMPX-II Master Interface Format obtained processing ENDF/B-IV data by means of various AMPX-II System modules are presented in this note both for the more reprocessing aspects and features of the generated component files-neutrons, photon and secondary gamma-ray production cross sections. As far as the neutron data are concerned there is the avaibility of 186 data sets regarding most significant fission products. Results of the additional validation of the neutron data pertaining to eighteen benchmark experiments are also given. Some calculational tests on both neutron and coupled data emphasize the important role of the secondary gamma-ray data in nuclear criticality safety calculations

  3. Measurement of thermal neutron cross-sections and resonance integrals for sup 7 sup 1 Ga(n,gamma) sup 7 sup 2 Ga and sup 7 sup 5 As(n,gamma) sup 7 sup 6 As by using sup 2 sup 4 sup 1 Am-Be isotopic neutron source

    CERN Document Server

    Karadag, M; Tan, M; Oezmen, A

    2003-01-01

    Thermal neutron cross-sections and resonance integrals for the sup 7 sup 1 Ga(n,gamma) sup 7 sup 2 Ga and sup 7 sup 5 As(n,gamma) sup 7 sup 6 As reactions were measured by the activation method. The experimental samples with and without a cylindrical Cd shield case in 1 mm wall thickness were irradiated in an isotropic neutron field of the sup 2 sup 4 sup 1 Am-Be neutron source. The induced activities in the samples were measured by high-resolution gamma-ray spectrometry with a calibrated reverse-electrode germanium detector. Thermal neutron cross-sections for 2200 m/s neutrons and resonance integrals for the sup 7 sup 1 Ga(n,gamma) sup 7 sup 2 Ga and sup 7 sup 5 As(n,gamma) sup 7 sup 6 As reactions have been obtained relative to the reference values, sigma sub 0 =13.3+-0.1 b and I sub 0 =14.0+-0.3 b for the sup 5 sup 5 Mn(n,gamma) sup 5 sup 6 Mn reaction as a single comparator. The necessary correction factors for gamma attenuation, thermal neutron and resonance neutron self-shielding effects were taken into...

  4. Pumpkin Seed Oil Attenuates Functional and Structural Disorders in Urogenital System of Male Albino Rats Induced by Whole Body Gamma Irradiation

    International Nuclear Information System (INIS)

    Rezk, R.G.; Darwish, M.R

    2012-01-01

    Pumpkin seeds have long been used for health benefits and the seed oil has been shown to contain active beneficial components that may protect from oxidative stress. The aim of the present study is to evaluate the modulator role of pumpkin seed oil (PSO) supplementation on gamma radiation induced changes in certain biochemical and histological abnormalities in both kidney and testes tissues. Male rats received 5Gy whole body gamma-irradiation delivered as 1 Gy day after day to result in a cumulative dose of 5 Gy. PSO was orally administered to rats (20mg/Kg body weight) for 20 consecutive days before irradiation and during the period of irradiation. On days seven and twenty one after the last irradiation dose, rats were sacrificed. Biochemical analysis in the serum revealed that PSO supplementation diminished the radiation-induced increase in the level of urea, creatinine , follicle stimulating hormone (FSH) and luteinizing hormone (LH). Significant amelioration of the radiation-induced decreases in calcium (Ca +2 ), potassium (K + ) and testosterone levels were also recorded. PSO administration has attenuated the toxic effects of radiation by decreasing the level of lipid peroxides measured as thiobarbituric acid reactive substances (TBARS) and increasing the activity of endogenous antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) and the content of glutathione (GSH). Histological observations of photomicrographs of kidney sections of irradiated rats showed amorphoid glomeruli, renal sclerosis and high content of inflammatory cells and fibroblasts, hemorrhage in glomeruli, ruptured proximal and distal convoluted tubules. Examination of testis tissues showed disappearance of seminiferous tubules, ruptured tunica albuginea, and degeneration of interstitial cells. PSO supplementation has obviously improved the radiation-induced histopathological changes in both tissues. It could be concluded that PSO can be used as a useful adjunct for maintaining

  5. A study of Venus surface elemental composition from 14 MeV neutron induced gamma ray spectroscopy: Activation analysis

    International Nuclear Information System (INIS)

    Jun, I.; Kim, W.; Smith, M.; Mitrofanov, I.; Litvak, M.

    2011-01-01

    The surface elemental composition of Venus can be determined using an artificially pulsed 14 MeV neutron generator (PNG) combined with a gamma ray spectrometer (GRS). The 14 MeV neutrons will interact with the surface materials and generate gamma rays, characteristic of specific elements, whose energy spectrum will be measured by GRS. These characteristic gamma rays are produced mainly through 3 different neutron interaction mechanisms: capture, inelastic, and activation reactions. Each reaction type has a different neutron energy dependency and different time scale for gamma ray production and transport. Certain elements are more easily identified through one reaction type over the others. Thus, careful analysis of the gamma ray spectra during and after the neutron pulse provides a comprehensive understanding of the surface elemental composition. In this paper, we use a well-tested neutron/gamma transport code, called Monte Carlo N-Particles (MCNP), to investigate the measurement capability of a PNG-GRS detection system through the neutron activation reactions. An activation analysis was performed for a representative soil composition of Venus with a notional operational scenario of PNG and GRS. The analysis shows that the proposed instrument concept can identify most of the modeled surface elements at Venus with sufficient accuracy through the activation mode. Specifically, U, Th, K, Si can be measured to within 1%, Fe within 2%, Al within 10%, Ca within 5%, Mg with 15%, Mn with 20%, and Cl within 6%. Although modeled in the analysis, it is shown that the activation mode alone cannot distinguish the S and Ti peaks.

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

    International Nuclear Information System (INIS)

    Ahlersova, E.; Kassayova, M.; Ahlers, I.

    1998-01-01

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

  7. Utilization of ilmenite/epoxy composite for neutrons and gamma rays attenuation

    Energy Technology Data Exchange (ETDEWEB)

    El-Sayed Abdo, A. E-mail: attiaabdo11@hotmail.com; El-Sarraf, M.A.; Gaber, F.A

    2003-01-01

    This work deals with the study of ilmenite/epoxy composite as an injecting mortar for cracks developed in biological concrete shields, as well as, neutrons and gamma rays attenuation. Effects of the particle size on the mechanical strengths have been studied for epoxy resin filled with crushed ilmenite with different maximum particle sizes ranging from 32 to 500 {mu}m. Thermal neutrons and gamma rays attenuation in ilmenite/epoxy composites with 75 and 80 wt.% of ilmenite concentration have been investigated. The total mass attenuation coefficients {mu}/{rho} (cm{sup 2} g{sup -1}) of gamma ray for five ilmenite/epoxy composites have been calculated using the XCOM program (version 3.1) at energies from 10 keV to 100 MeV. Also, the total mass attenuation coefficients ({mu}/{rho}) have estimated based on the measured total linear attenuation coefficients ({mu}) and compared with the calculated results where, a reasonable agreement was found.

  8. Geiger-Mueller counter for mixed neutron-gamma beam dosimetry

    International Nuclear Information System (INIS)

    McDonald, J.C.; Ma, I.-C.

    1978-01-01

    A Geiger-Mueller (G-M) dosimeter has been constructed and employed to measure the gamma-ray component of absorbed dose in a cyclotron produced fast neutron field. This instrument is waterproof for measurements in a liquid medium, and read-out is accompanied with any standard scaler. (Auth.)

  9. Fast-neutron and gamma-ray imaging with a capillary liquid xenon converter coupled to a gaseous photomultiplier

    Science.gov (United States)

    Israelashvili, I.; Coimbra, A. E. C.; Vartsky, D.; Arazi, L.; Shchemelinin, S.; Caspi, E. N.; Breskin, A.

    2017-09-01

    Gamma-ray and fast-neutron imaging was performed with a novel liquid xenon (LXe) scintillation detector read out by a Gaseous Photomultiplier (GPM). The 100 mm diameter detector prototype comprised a capillary-filled LXe converter/scintillator, coupled to a triple-THGEM imaging-GPM, with its first electrode coated by a CsI UV-photocathode, operated in Ne/5%CH4 at cryogenic temperatures. Radiation localization in 2D was derived from scintillation-induced photoelectron avalanches, measured on the GPM's segmented anode. The localization properties of 60Co gamma-rays and a mixed fast-neutron/gamma-ray field from an AmBe neutron source were derived from irradiation of a Pb edge absorber. Spatial resolutions of 12± 2 mm and 10± 2 mm (FWHM) were reached with 60Co and AmBe sources, respectively. The experimental results are in good agreement with GEANT4 simulations. The calculated ultimate expected resolutions for our application-relevant 4.4 and 15.1 MeV gamma-rays and 1-15 MeV neutrons are 2-4 mm and ~ 2 mm (FWHM), respectively. These results indicate the potential applicability of the new detector concept to Fast-Neutron Resonance Radiography (FNRR) and Dual-Discrete-Energy Gamma Radiography (DDEGR) of large objects.

  10. Possibility of semiconductor counters application for internal contamination measurement of whole human body

    International Nuclear Information System (INIS)

    Cunic, O.; Orlic, M.; Bek-Uzarov, Dj.; Pavlovic, S.; Pavlovic, R.

    1997-01-01

    The possibility of high resolution semiconductor counters application in 'Vinca' Whole Body Counter for direct beta-gamma internal contamination measurement are discussed, assuming the following relevant characteristics: efficiency, resolution and counter price. A comparison with appropriate characteristics of NaI(Tl) crystal used in 'Vinca' WBC is treated. It is evident that the scintillation counters have the higher detection efficiency, but HPGe counters having much better resolution and recently lowest prices are also acceptable to join the existing NaI(Tl) counters with the HPGe counters in the same time, allow better spectral analyses of the human body activity and additionally more precise estimation of the equivalent doses rate which is generally a essential problem in WBC measurements. (author)

  11. Optimum filter-based discrimination of neutrons and gamma rays

    International Nuclear Information System (INIS)

    Amiri, Moslem; Prenosil, Vaclav; Cvachovec, Frantisek

    2015-01-01

    An optimum filter-based method for discrimination of neutrons and gamma-rays in a mixed radiation field is presented. The existing filter-based implementations of discriminators require sample pulse responses in advance of the experiment run to build the filter coefficients, which makes them less practical. Our novel technique creates the coefficients during the experiment and improves their quality gradually. Applied to several sets of mixed neutron and photon signals obtained through different digitizers using stilbene scintillator, this approach is analyzed and its discrimination quality is measured. (authors)

  12. Measurement of prompt fission gamma-ray spectra in fast neutron-induced fission

    International Nuclear Information System (INIS)

    Laborie, J.M.; Belier, G.; Taieb, J.

    2012-01-01

    Knowledge of prompt fission gamma-ray emission has been of major interest in reactor physics for a few years. Since very few experimental spectra were ever published until now, new measurements would be also valuable to improve our understanding of the fission process. An experimental method is currently being developed to measure the prompt fission gamma-ray spectrum from some tens keV up to 10 MeV at least. The mean multiplicity and total energy could be deduced. In this method, the gamma-rays are measured with a bismuth germanate (BGO) detector which has the advantage to present a high P/T ratio and a high efficiency compared to other gamma-ray detectors. The prompt fission neutrons are rejected by the time of flight technique between the BGO detector and a fission trigger given by a fission chamber or a scintillating active target. Energy and efficiency calibration of the BGO detector were carried out up to 10.76 MeV by means of the Al-27(p, gamma) reaction. First prompt fission gamma-ray spectrum measurements performed for the spontaneous fission of Cf-252 and for 1.7 and 15.6 MeV neutron-induced fission of U-238 at the CEA, DAM, DIF Van de Graaff accelerator, will be presented. (authors)

  13. Development of automatic gamma and neutron monitoring system for PFBR fuel subassemblies at IFSB

    International Nuclear Information System (INIS)

    Krishnakumar, D.N.; Dhanasekaran, A.; Ajoy, K.C.; Jose, M.T.; Baskaran, R.; Sureshkumar, K.V.

    2018-01-01

    Health physics surveillance during PFBR fuel pin assembling operation at Interim Fuel Storage Building (IFSB) mandates scanning of the fuel assembly using Telector and Rem counter to find out the maximum gamma and neutron dose rates respectively. Throughout the process health physicist involved in the operation must hold the survey meter at a constant distance from the subassembly and simultaneously should make a note of dose rate values displayed. This practice might lead to the occupational exposures and also might induce human errors during measurements. To make this process more simple, faultless and effortless, an automatic Gamma Neutron Monitoring System (AGNMS) is designed and developed at RSD to measure, store and visualize instantaneous gamma and neutron dose rates of PFBR fuel subassembly. Development of the system, calibration and deployment of the system at IFSB and preliminary results obtained using the system is depicted in this paper

  14. Characteristic Investigation of Unfolded Neutron Spectra with Different Priori Information and Gamma Radiation Interference

    International Nuclear Information System (INIS)

    Kim, Bong Hwan

    2006-01-01

    Neutron field spectrometry using multi spheres such as Bonner Spheres (BS) has been almost essential in radiation protection dosimetry for a long time at workplace in spite of poor energy resolution because it is not asking the fine energy resolution but requiring easy operation and measurement performance over a wide range of energy interested. KAERI has developed and used extended BS system based on a LiI(Eu) scintillator as the representative neutron spectrometry system for workplace monitoring as well as for the quantification of neutron calibration fields such as those recommended by ISO 8529. Major topics in using BS are how close the unfolded spectra is the real one and to minimize the interference of gamma radiation in neutron/gamma mixed fields in case of active instrument such as a BS with a LiI(Eu) scintillator. The former is related with choosing a priori information when unfolding the measured data and the latter is depend on how to discriminate it in intense gamma radiation fields. Influence of a priori information in unfolding and effect of counting loss due to pile-up of signals for the KAERI BS system were investigated analyzing the spectral measurement results of Scattered Neutron Calibration Fields (SNCF)

  15. Value of whole body 123I scan for detection of metastasis in patients with well-differentiated thyroid carcinoma

    International Nuclear Information System (INIS)

    Takahashi, Naoya; Odano, Ikuo; Sugita, Tadashi; Sato, Yoko; Sakai, Kunio

    1995-01-01

    To evaluate the utility of 123 I whole body scan for detection of metastasis in patients with well-differentiated thyroid carcinoma, post-therapy whole body 131 I images in 55 cases were compared with pre-therapy 123 I images using diagnostic dose (74 MBq). The post-therapy studies were performed 7 days after administration of therapeutic doses (3.33-7.77 GBq) of 131 I. The pre-therapy scans showed 30 lesions (71.4%) of 42 lesions which were shown by 131 I post-therapy scans. The diagnostic accuracy of 123 I whole body scans was considered to be nearly the same as the images obtained by 131 I using diagnostic dose. 123 I has short-life and an optimum gamma ray energy for scintigraphy. It makes radiation dose to patients lower than that of 131 I. Therefore, we recommend pre-therapy 131 I image using diagnostic dose is replaced by 123 I image. (author)

  16. Evaluation of the total gamma-ray production cross-sections for nonelastic interaction of fast neutrons with iron nuclei

    International Nuclear Information System (INIS)

    Savin, M.V.; Nefedov, Yu.Ya; Livke, A.V.; Zvenigorodskij, A.G.

    2001-01-01

    Experimental data on the total gamma-ray production cross-sections for inelastic interaction of fast neutrons with iron nuclei were analysed. The total gamma-ray production cross-sections, grouped according to E γ , were evaluated in the neutron energy range 0.5-19 MeV. The statistical spline approximation method was used to evaluate the experimental data. Evaluated data stored in the ENDF, JENDL, BROND, and other libraries on gamma-ray production spectra and cross-sections for inelastic interaction of fast neutrons with iron nuclei, were analysed. (author)

  17. 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

  18. Radio-prophylactic treatment with imidazole and/or Serotonin for Modulation of Tissue Catecholamines in whole body gamma irradiated Rats

    International Nuclear Information System (INIS)

    Hassan, S.H.M.; Roushdy, H.M.; Maklaad, Y.A.; El-Sayed, M.E.

    1995-01-01

    The present study has been conducted to evaluate the radioprotective effects of imidazole, serotonin and their combination on radiation induced reduction in catecholamine contents of the heart and adrenal glands in albino rat. The contribution of catecholamines in the radioprotective role of these agents has been evaluated. Whole-body gamma-irradiation (6 Gy) induced a significant reduction in heart and adrenal glands contents of catecholamine (epinephrine, norepinephrine and dopamine) one day post irradiation. Such reduction in catecholamine contents was more pronounced on the seventh day post exposure. Administration of imidazole (350 mg kg-1) or serotonin. (15 mg. kg-1) controlled the radiation induced reduction in catecholamine contents of heart as well as adrenal glands. Whereas, combination of imidazole (17 mg kg-1) serotonin (15 mg. kg-1) afforded a better protection than either agent given alone, in view that all the measured parameters could be fully restored to the values pre-irradiation. This study appreciate the usage of such combination as a prophylactic treatment for controlling the stress-state induced by irradiation which is associated with disturbed level of endogenous catecholamine contents in those sensitive patients undergoing radiotherapy. 2 tabs

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

    Science.gov (United States)

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

    1984-08-16

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

  20. Quantitative comparison between experimental and simulated gamma-ray spectra induced by 14 MeV tagged neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Perot, B., E-mail: bertrand.perot@cea.fr [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); El Kanawati, W.; Carasco, C.; Eleon, C. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Valkovic, V. [A.C.T.d.o.o., Prilesje 4, 10000 Zagreb (Croatia); Sudac, D.; Obhodas, J. [Ruder Boskovic Institute, Bijenicka c. 54, 10000 Zagreb (Croatia); Sannie, G. [CEA, LIST, Saclay, F-91191 Gif-sur-Yvette (France)

    2012-07-15

    Fast neutron interrogation with the associated particle technique can be used to identify explosives in cargo containers (EURITRACK FP6 project) and unexploded ordnance on the seabed (UNCOSS FP7 project), by detecting gamma radiations induced by 14 MeV neutrons produced in the {sup 2}H({sup 3}H,{alpha})n reaction. The origin of the gamma rays can be determined in 3D by the detection of the alpha particle, which provides the direction of the opposite neutron and its time-of-flight. Gamma spectroscopy provides the relative counts of carbon, nitrogen, and oxygen, which are converted to chemical fractions to differentiate explosives from other organic substances. To this aim, Monte Carlo calculations are used to take into account neutron moderation and gamma attenuation in cargo materials or seawater. This paper presents an experimental verification that C, N, and O counts are correctly reproduced by numerical simulation. A quantitative comparison is also reported for silicon, iron, lead, and aluminium. - Highlights: Black-Right-Pointing-Pointer Gamma-ray spectra produced by 14 MeV neutrons in C, N, O, Si, Al, Fe, and Pb elements. Black-Right-Pointing-Pointer Quantitative comparison with MCNPX simulations using the ENDF/B-VII.0 library. Black-Right-Pointing-Pointer C, N, and O counts correctly reproduced and chemical proportions recovered using calculation. Black-Right-Pointing-Pointer Application to the detection of explosives or illicit drugs in cargo containers.

  1. Development of a new deuterium-deuterium (D-D) neutron generator for prompt gamma-ray neutron activation analysis.

    Science.gov (United States)

    Bergaoui, K; Reguigui, N; Gary, C K; Brown, C; Cremer, J T; Vainionpaa, J H; Piestrup, M A

    2014-12-01

    A new deuterium-deuterium (D-D) neutron generator has been developed by Adelphi Technology for prompt gamma neutron activation analysis (PGNAA), neutron activation analysis (NAA), and fast neutron radiography. The generator makes an excellent fast, intermediate, and thermal neutron source for laboratories and industrial applications that require the safe production of neutrons, a small footprint, low cost, and small regulatory burden. The generator has three major components: a Radio Frequency Induction Ion Source, a Secondary Electron Shroud, and a Diode Accelerator Structure and Target. Monoenergetic neutrons (2.5MeV) are produced with a yield of 10(10)n/s using 25-50mA of deuterium ion beam current and 125kV of acceleration voltage. The present study characterizes the performance of the neutron generator with respect to neutron yield, neutron production efficiency, and the ionic current as a function of the acceleration voltage at various RF powers. In addition the Monte Carlo N-Particle Transport (MCNP) simulation code was used to optimize the setup with respect to thermal flux and radiation protection. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Gamma-ray production cross-sections for the interactions of 14.9 MeV neutrons with Si, Cu, Nb and Pb

    International Nuclear Information System (INIS)

    Fan Guoying

    1991-12-01

    Gamma rays produced in the interactions of 14.9 MeV neutrons with Si, Cu, Nb and Pb targets were studied. The neutron beam was produced with the T(d,n)He reaction using 300 KeV Cockroft-Walton accelerator. Absolute neutron flux was determined by the associated particle technique. The time-of-flight technique was used to reduce the background. The FWHM of neutron pulses was 1.5 ns. A Ge(Li) detector was used for gamma-ray detection. 39 gamma lines for Si, 39 gamma lines for Cu, 79 for Nb and 39 for Pb were detected. Most of these gamma rays were emitted in (n,γ), (n,n') and (n,2n) reactions. The measurements were made at 40 deg. C, 55 deg. C, 125 deg. C and 140 deg. C relative to the incident neutron beam. The results are presented in the form of the data tables. 9 refs, 11 figs, 19 tabs

  3. Angular Distribution of Gamma Rays from the Fission of {sup 235}U Induced by 14-Mev Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Jeki, L.; Kluge, Gy.; Lajtai, A. [Central Research Institute for Physics, Hungarian Academy of Sciences (Hungary)

    1969-12-15

    Experiments are reported which were performed to study the angular distribution of the gamma radiation following fast-neutron-induced nuclear fission. The investigations were, in particular, focussed on the influence which the angular momentum imparted to the compound nucleus by the fast neutrons has on the angular distribution of the {gamma}-rays. The fission of {sup 235}U is induced by 14-MeV-energy neutrons from the T(d, n) {alpha} reaction. The fission fragments are detected by a gas-scintillation counter filled with a mixture of Ar and Ni gases, the {gamma}-rays by 5 cm x 5 cm Nal(Tl) crystal with an energy threshold of 120 keV. The intensity of the {gamma}-rays is measured at 90 Degree-Sign and 174 Degree-Sign to the direction of fragment motion. The flight times of fission neutrons and {gamma}-rays are measured with a 20-ns overlap-type time-to-pulse height converter while the background was covered simultaneously with another converter delayed with respect to the former. The signals from both converters are analysed by a multichannel analyser with divisible memory. The flight path, which is chosen to be about 70 cm, makes it possible to separate the neutron from the gamma counts. The geometry is designed to keep the direction of the outflying fission fragments nearly the same as that of the incident fast neutrons. In this way the angular momenta of the fast neutrons are normal to the flight path of the fragments. The measured gamma intensities are extrapolated to 180 Degree-Sign on a computer using Strutinski's formula n( Greek-Theta-Symbol ) {approx}1 + B sin Greek-Theta-Symbol . On transformation of the measured data from the laboratory system to the system of fragments the anisotropy is found to be A = 1(180 Degree-Sign )/l (90 Degree-Sign ) = 1.33 {+-} 0.05. The main angular momentum of fission fragments is calculated from the anisotropy as 15 h units. As compared with the thermal-neutron-induced fission the present results indicate an additional

  4. Use of integral experiments to improve neutron propagation and gamma heating calculations

    International Nuclear Information System (INIS)

    Oceraies, Y.; Caumette, P.; Devillers, C.; Bussac, J.

    1979-01-01

    1) The studies to define and improve the accuracies of neutron propagation and gamma heating calculations from integral experiments are encompassed in the field of the fast reactor physics program at CEA. 2) A systematic analysis of neutron propagation in Fe-Na clean media, with variable volumic composition between 0 and 100% in sodium, has been performed on the HARMONIE source reactor. Gamma heating traverses in the core, the blankets and several control rods, have been measured in the R Z core program at MASURCA. The experimental techniques, the accuracies and the results obtained are given. The approximations of the calculational methods used to analyse these experiments and to predict the corresponding design parameters are also described. 3) Particular emphasis is given to the methods planned to improve fundamental data used in neutron propagation calculations, using the discrepancies observed between measured and calculated results in clean integral experiments. One of these approaches, similar to the techniques used in core physics, relies upon sensitivity studies and eventually on adjustment techniques applied to neutron propagation. (author)

  5. Sample design and gamma-ray counting strategy of neutron activation system for triton burnup measurements in KSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Jungmin [Department of Energy System Engineering, Seoul National University, Seoul (Korea, Republic of); Cheon, Mun Seong [ITER Korea, National Fusion Research Institute, Daejeon (Korea, Republic of); Chung, Kyoung-Jae, E-mail: jkjlsh1@snu.ac.kr [Department of Energy System Engineering, Seoul National University, Seoul (Korea, Republic of); Hwang, Y.S. [Department of Energy System Engineering, Seoul National University, Seoul (Korea, Republic of)

    2016-11-01

    Highlights: • Sample design for triton burnup ratio measurement is carried out. • Samples for 14.1 MeV neutron measurements are selected for KSTAR. • Si and Cu are the most suitable materials for d-t neutron measurements. • Appropriate γ-ray counting strategies for each selected sample are established. - Abstract: On the purpose of triton burnup measurements in Korea Superconducting Tokamak Advanced Research (KSTAR) deuterium plasmas, appropriate neutron activation system (NAS) samples for 14.1 MeV d-t neutron measurements have been designed and gamma-ray counting strategy is established. Neutronics calculations are performed with the MCNP5 neutron transport code for the KSTAR neutral beam heated deuterium plasma discharges. Based on those calculations and the assumed d-t neutron yield, the activities induced by d-t neutrons are estimated with the inventory code FISPACT-2007 for candidate sample materials: Si, Cu, Al, Fe, Nb, Co, Ti, and Ni. It is found that Si, Cu, Al, and Fe are suitable for the KSATR NAS in terms of the minimum detectable activity (MDA) calculated based on the standard deviation of blank measurements. Considering background gamma-rays radiated from surrounding structures activated by thermalized fusion neutrons, appropriate gamma-ray counting strategy for each selected sample is established.

  6. Prompt gamma neutron activation analysis facility at the RA-6 research reactor

    International Nuclear Information System (INIS)

    Sanchez, F. A.; Calzetta, O

    2004-01-01

    A prompt gamma neutron activation activation analysis facility was developed at the 500 kw thermal power RA-6 research reactor of the Bariloche Atomic Center, Argentina.This facility consist of a radial beam port with external positioning of the sample.The gamma radiation is reduced by a bismuth filter placed inside the extraction tube and the beam diameter is limited by a set of two collimators up to 5 cm.The neutron flux at the sample position is 7 10 6 n/cm 2 s with a Cadmium ratio of 20/1.The gamma detector is a 50 % efficiency type p HPGe rounded by a NaI(Tl) for Compton suppressioning.The gamma spectra is measured through 0 to 8.5 MeV.The background have counting rate of 350 cps without sample. In this work is shown the efficiency curve, the calculed sensibilities and the lower detection limits for B, Cd, Sm, Gd, H, Cl, Hg, Eu, Ti, Ag, Au, Mo. The RA-6's PGNAA facility is fully working, although the analytic capacity is under improvement [es

  7. Analysis of the propagation of neutrons and gamma-rays from the fast neutron source reactor YAYOI

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Shigeo, E-mail: neutron@keyaki.cc.u-tokai.ac.jp [Department of Energy Science and Engineering, School of Engineering, Tokai University, Hiratsuka, Kanagawa 259-1292 (Japan); Murata, Isao [Division of Electrical, Electronic and Information Engineering, Osaka University, Suita, Osaka 565-0871 (Japan); Nakagawa, Tsutomu; Saito, Isao [Nuclear Professional School, School of Engineering, The University of Tokyo, Tokai-mura, Naka-gun, Ibaraki 319-1188 (Japan)

    2011-10-01

    The skyshine effect is crucial for designing appropriate shielding. To investigate the skyshine effect, the propagation of neutrons was measured and analyzed at the fast neutron source reactor YAYOI. Pulse height spectra and dose distributions of neutron and secondary gamma-ray were measured outside YAYOI, and analyzed with MCNP-5 and JENDL-3.3. Comparison with the experimental results showed good agreement. Also, a semi-empirical formula was successfully derived to describe the dose distribution. The formulae can be used to predict the skyshine effect at YAYOI, and will be useful for estimating the skyshine effect and designing the shield structure for fusion facilities.

  8. Determination of dose components in mixed gamma neutron fields by use of high pressure ionization chambers

    International Nuclear Information System (INIS)

    Golnik, N.; Pliszczynski, T.; Wysocka, A.; Zielczynski, M.

    1985-01-01

    The two ionization chamber method for determination of dose components in mixed γ-neutron field has been improved by increasing gas pressure in the chambers up to some milions pascals. Advantages of high pressure gas filling are the followings: 1) significant reduction of the ratio of neutron-to gamma sensitivity for the hydrogen-free chamber, 2) possibility of sensitivity correction for both chambers by application of appropriate voltage, 3) high sensitivity for small detectors. High-pressure, pen-like ionization chambers have been examined in fields of different neutron sources: a TE-chamber, filled with 0.2 MPa of quasi-TE-gas and a conductive PTFE chamber, filled with 3.1 MPa of CO 2 . The ratio of neutron-to-gamma sensitivity for the PTFE chamber, operated at electrical field strength below 100 V/cm, has not exceeded 0.01 for neutrons with energy below 8 MeV. Formula is presented for calculation of this ratio for any high-pressure, CO 2 -filled ionization chamber. Contribution of gamma component to total tissue dose in the field of typical neutron sources has been found to be 3 to 70%

  9. The determination of the thermal neutron and gamma fluxes at the Maryland University Training Reactor using thermoluminescent dosimetry

    International Nuclear Information System (INIS)

    Karceski, Jeffrey David; Ebert, David D.; Munno, Frank J.

    1988-01-01

    Determination of the dose received by a material in a mixed gamma and neutron field is of paramount concern to any research reactor owner. This dose can be separated into three distinguishable parts using standard thermoluminescent dosimetry (TLD) responses: 1) thermal neutron dose, 2) fission gamma dose, and 3) fission product gamma dose. For the Maryland University Training Reactor (MUTR), these respective fluences were determined for each of the associated experimental facilities. Quantifying the magnitude of the gamma and thermal neutron exposures at various reactor power levels was accomplished using Li-6F and Li-7F TLDs, respectively. These two types of dosimetry were chosen given the following considerations: 1) there is no existing standard established for fluence determination in a mixed field, 2) the LiF TLDs have a wide range of sensitivity to radiation, from 0.01 mR to 10,000 R, and 3) LiF TLDs are easy to read given the proper equipment. Standardization of the gamma/neutron doses was accomplished using the 500,000 Rad/hr Co-60 gamma source also located at the University of Maryland. (author)

  10. Fast neutron and gamma-ray transmission technique in mixed samples. MCNP calculations

    International Nuclear Information System (INIS)

    Perez, N.; Padron, I.

    2001-01-01

    In this paper the moisture in sand and also the sulfur content in toluene have been described by using the simultaneous fast neutron/gamma transmission technique (FNGT). Monte Carlo calculations show that it is possible to apply this technique with accelerator-based and isotopic neutron sources in the on-line analysis to perform the product quality control, specifically in the building materials industry and the petroleum one. It has been used particles from a 14MeV neutron generator and also from an Am-Be neutron source. The estimation of optimal system parameters like the efficiency, detection time, hazards and costs were performed in order to compare both neutron sources

  11. Investigation of a whole-body DOI-PET system

    International Nuclear Information System (INIS)

    Ohi, Junichi; Tonami, Hiromichi

    2007-01-01

    In this study, we were conducting basic research on a whole-body depth of gamma-ray interaction (DOI) positron emission tomography system which provides spatial resolution that is both high and uniform, and also minimizes costs. The detectors consist of double-layer 9x10 GSO/GSO phoswich crystal blocks, a light guide and two rectangular PMTs. Individual crystal sizes are 2.45x5.1x15 mm 3 , and each layer of crystal blocks has a different decay time. Many of the circuit boards used in our current conventional PET system (SET-3000G SHIMADZU Japan) have been optimized for DOI acquisition. The detectors are arranged to form a 332.5 mm radius detection ring, and spatial resolution is obtained from the center to the edge of the 250 mm radius field of view. The effect of DOI was confirmed using a comparison with the non-DOI systems

  12. The response of some health physics instruments to sodium-24 and chlorine-38 activities in polythene man-phantoms and the human body

    International Nuclear Information System (INIS)

    Peabody, C.O.

    1963-12-01

    Measurements have been made of the response of five commonly used Health Physics instruments when held near polythene man-phantoms filled with aqueous solutions containing sodium-24 and chlorine-38 activities. The instruments discussed are the Type 1413A, 1597A and 1368A ratemeters, the E.M.I. PCM1 contamination monitor and the Type 1021C beta-gamma probe. The ratios of the whole-body chlorine-38 and sodium-24 activities are calculated for various periods of accidental human irradiation by neutrons. These ratios and the phantom results are used to estimate the response of the five instruments when held near the human body at various times after irradiation. The relative contributions of the chlorine-38 and sodium-24 to the instrument indications are listed. The tabulated data enable the instrument readings to be converted to whole-body sodium-24 activity at the time of irradiation. This may be used as a quick estimate of the degree of neutron irradiation. (author)

  13. The effects of gamma irradiation on neutron displacement sensitivity of lateral PNP bipolar transistors

    International Nuclear Information System (INIS)

    Wang, Chenhui; Chen, Wei; Liu, Yan; Jin, Xiaoming; Yang, Shanchao; Qi, Chao

    2016-01-01

    The effects of gamma irradiation on neutron displacement sensitivity of four types of lateral PNP bipolar transistors (LPNPs) with different neutral base widths, emitter widths and the doping concentrations of the epitaxial base region are studied. The physical mechanisms of the effects are explored by defect analysis using deep level transient spectroscopy (DLTS) techniques and numerical simulations of recombination process in the base region of the lateral PNP bipolar transistors, and are verified by the experiments on gate-controlled lateral PNP bipolar transistors (GCLPNPs) manufactured in the identical commercial bipolar process with different gate bias voltage. The results indicate that gamma irradiation increases neutron displacement damage sensitivity of lateral PNP bipolar transistors and the mechanism of this phenomenon is that positive charge induced by gamma irradiation enhances the recombination process in the defects induced by neutrons in the base region, leading to larger recombination component of base current and greater gain degradation.

  14. The effects of gamma irradiation on neutron displacement sensitivity of lateral PNP bipolar transistors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chenhui, E-mail: wangchenhui@nint.ac.cn; Chen, Wei; Liu, Yan; Jin, Xiaoming; Yang, Shanchao; Qi, Chao

    2016-09-21

    The effects of gamma irradiation on neutron displacement sensitivity of four types of lateral PNP bipolar transistors (LPNPs) with different neutral base widths, emitter widths and the doping concentrations of the epitaxial base region are studied. The physical mechanisms of the effects are explored by defect analysis using deep level transient spectroscopy (DLTS) techniques and numerical simulations of recombination process in the base region of the lateral PNP bipolar transistors, and are verified by the experiments on gate-controlled lateral PNP bipolar transistors (GCLPNPs) manufactured in the identical commercial bipolar process with different gate bias voltage. The results indicate that gamma irradiation increases neutron displacement damage sensitivity of lateral PNP bipolar transistors and the mechanism of this phenomenon is that positive charge induced by gamma irradiation enhances the recombination process in the defects induced by neutrons in the base region, leading to larger recombination component of base current and greater gain degradation.

  15. Measurement of 235U content and flow of UF6 using delayed neutrons or gamma rays following induced fission

    International Nuclear Information System (INIS)

    Stromswold, D.C.; Peurrung, A.J.; Reeder, P.L.; Perkins, R.W.

    1996-06-01

    Feasibility experiments conducted at Pacific Northwest National Laboratory demonstrate that either delayed neutrons or energetic gamma rays from short-lived fission products can be used to monitor the blending of UF 6 gas streams. A 252 Cf neutron source was used to induce 235 U fission in a sample, and delayed neutrons and gamma rays were measured after the sample moved open-quotes down-stream.close quotes The experiments used a UO 2 powder that was transported down the pipe to simulate the flowing UF 6 gas. Computer modeling and analytic calculation extended the test results to a flowing UF 6 gas system. Neutron or gamma-ray measurements made at two downstream positions can be used to indicate both the 235 U content and UF 6 flow rate. Both the neutron and gamma-ray techniques have the benefits of simplicity and long-term reliability, combined with adequate sensitivity for low-intrusion monitoring of the blending process. Alternatively, measuring the neutron emission rate from (a, n) reactions in the UF 6 provides an approximate measure of the 235 U content without using a neutron source to induce fission

  16. Sample dependent response of a LaCl{sub 3}:Ce detector in prompt gamma neutron activation analysis of bulk hydrocarbon samples

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A., E-mail: aanaqvi@kfupm.edu.sa [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Al-Matouq, Faris A.; Khiari, F.Z. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Isab, A.A. [Department of Chemistry, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Khateeb-ur-Rehman,; Raashid, M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2013-08-11

    The response of a LaCl{sub 3}:Ce detector has been found to depend upon the hydrogen content of bulk samples in prompt gamma analysis using 14 MeV neutron inelastic scattering. The moderation of 14 MeV neutrons from hydrogen in the bulk sample produces thermal neutrons around the sample which ultimately excite chlorine capture gamma rays in the LaCl{sub 3}:Ce detector material. Interference of 6.11 MeV chlorine gamma rays from the detector itself with 6.13 MeV oxygen gamma rays from the bulk samples makes the intensity of the 6.13 MeV oxygen gamma ray peak relatively insensitive to variations in oxygen concentration. The strong dependence of the 1.95 MeV doublet chlorine gamma ray yield on hydrogen content of the bulk samples confirms fast neutron moderation from hydrogen in the bulk samples as a major source of production of thermal neutrons and chlorine gamma rays in the LaCl{sub 3}:Ce detector material. Despite their poor oxygen detection capabilities, these detectors have nonetheless excellent detection capabilities for hydrogen and carbon in benzene, butyl alcohol, propanol, propanic acid, and formic acid bulk samples using 14 MeV neutron inelastic scattering.

  17. Pulsed neutron generator system for astrobiological and geochemical exploration of planetary bodies

    International Nuclear Information System (INIS)

    Akkurt, Hatice; Groves, Joel L.; Trombka, Jacob; Starr, Richard; Evans, Larry; Floyd, Samuel; Hoover, Richard; Lim, Lucy; McClanahan, Timothy; James, Ralph; McCoy, Timothy; Schweitzer, Jeffrey

    2005-01-01

    A pulsed neutron/gamma-ray detection system for use on rovers to survey the elemental concentrations of Martian and Lunar surface and subsurface materials is evaluated. A robotic survey system combining a pulsed neutron generator (PNG) and detectors (gamma ray and neutron) can measure the major constituents to a depth of about 30 cm. Scanning mode measurements can give the major elemental concentrations while the rover is moving; analyzing mode measurements can give a detailed elemental analysis of the adjacent material when the rover is stationary. A detailed map of the subsurface elemental concentrations will provide invaluable information relevant to some of the most fundamental astrobiological questions including the presence of water, biogenic activity, life habitability and deposition processes

  18. Neutron and gamma ray streaming experiments at the fast neutron source reactor 'YAYOI'

    International Nuclear Information System (INIS)

    Oka, Yoshiaki; Yanagisawa, Ichiro; Akiyama, Masatsugu; An, Shigehiro

    1979-07-01

    Neutron and gamma ray streaming experiments were performed in the ducts and cavities that were located in the heavy concrete shields of the fast neutron source reactor YAYOI of University of Tokyo. The configurations have the feature that the streaming through the ducts are occurred following the scattering in the cavity. The axes of the ducts are perpendicular to the source radiation from the core. The spectrum of the source was modified by putting a plug in the beam hole of the core. An aluminum plug and the plug which contains paraffin were used. The decay in the ducts, however, hardly depends on the source spectrum. The decay in the ducts is nearly exponential. (author)

  19. Thyroxine clearance in rats within the first month after the single whole-body {gamma} - irradiation at a dose of 10Gy

    Energy Technology Data Exchange (ETDEWEB)

    Pryadko, Kirill A. [Institute of Radiobiology, National Academy of Sciences, Minsk (Belarus)

    2002-07-01

    The effects of acute whole-body {gamma} -irradiation at a dose of 10 Gy on thyroxine (T{sub 4}) plasma clearance rate (PCR) and thyroidal and blood T4 concentration ([T{sub 4}]) were examined within one month after exposure. The PCR values were measured using the bolus injection, single-compartmental approach. To eliminate the influence of radiation-induced anorexia animals were fasting for two days before the pharmacokinetic experiments. Hormone concentrations in blood and in thyroid tissue were measured by RIA. Throughout the observation period, PCR was elevated in irradiated rats with maximum at day 4 after exposure (0.56{+-}0.04 vs. 0.36{+-}0.03 ml/h100 gbw, P<0.001). [T{sub 4}] in blood was not significantly different from that in control animals. Thyroidal [T{sub 4}] was significantly decreased in irradiated animals 4 days after exposure (151.8{+-}21.7 vs. 258.8{+-}29.9 pmol/mg protein, P<0.01) and gradually increased after day 9. 10 Gy {gamma} -irradiation causes the intensification of T{sub 4} metabolism without the pronounced changes in concentration. Presumably, at early terms the rising local demand in O{sub 4} can not be compensated with the existing level of production. Alterations in the intensity of T{sub 4} metabolism are evident at least one month after exposure but they may not be detected without taking into account kinetic data.

  20. The establishment of bed type germanium-based whole body counters

    International Nuclear Information System (INIS)

    Chen, M.C.; Sun, C.L.; Yeh, W.W.

    1996-01-01

    A coaxial germanium detector was installed in a shadow-shield counter for the in-vivo measurement of γ emitters in the body. It is divided into two subparts, automatic liquid nitrogen transfer system and the Ge-based counting system. The automatic liquid nitrogen transfer system and a complete gamma spectroscopy software package were manufactured by EG and G ORTEC company. Some experiments were finished to get the optimum three setting parameters for how to operate the auto liquid nitrogen transfer system in good conditions. The filling interval should be setting at eight hours, the filling time should be setting at ten minutes, and the pressure of dewar should operate in a range from 14 to 26 PSI. The RMC-II phantom that is designed by Canberra company is used as standard man for all kinds of calibrations. The detector has resolutions that are less than 2.5 keV with an average of 1.87 keV for the 60 Co 1.33-MeV γ-ray peak. The efficiency value of thyroid geometry for four different organs is highest in the phantom. The resolution of the Germanium detector for measuring radioactivity in the body that is better than the sodium iodide detector is used to measure the internal depositions of radionuclide mixtures. So, the advantage of the germanium counter can just compensate the disadvantage of the NaI(TI) detector. The qualitative and quantitative analysis for whole body counting can keep in the best conditions if both whole body counters are operated at the same time for routine measurement purpose in the laboratory

  1. Use of pulsed neutron-neutron logging, thermal neutron-neutron logging, and gamma logging methods in classification for sand-clay sediments of Lower Cretaceous in Prikumsk oil-and-gas region according to filtration-capacitance characteristics

    International Nuclear Information System (INIS)

    Maksimenko, A.N.; Basin, Ya.N.; Novgorodov, V.A.

    1974-01-01

    To isolate reservoirs, the formation and deformation penetration zone parameters are used. They are estimated according to the false oil saturation factor and the time of the penetration zone deformation which are determined from the complex exploration of cased wells using the pulse neutron logging, thermal neutron-neutron logging and gamma logging techniques

  2. Total body neutron activation analysis of calcium: calibration and normalisation

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, N S.J.; Eastell, R; Ferrington, C M; Simpson, J D; Strong, J A [Western General Hospital, Edinburgh (UK); Smith, M A; Tothill, P [Royal Infirmary, Edinburgh (UK)

    1982-05-01

    An irradiation system has been designed, using a neutron beam from a cyclotron, which optimises the uniformity of activation of calcium. Induced activity is measured in a scanning, shadow-shield whole-body counter. Calibration has been effected and reproducibility assessed with three different types of phantom. Corrections were derived for variations in body height, depth and fat thickness. The coefficient of variation for repeated measurements of an anthropomorphic phantom was 1.8% for an absorbed dose equivalent of 13 mSv (1.3 rem). Measurements of total body calcium in 40 normal adults were used to derive normalisation factors which predict the normal calcium in a subject of given size and age. The coefficient of variation of normalised calcium was 6.2% in men and 6.6% in women, with the demonstration of an annual loss of 1.5% after the menopause. The narrow range should make single measurements useful for diagnostic purposes.

  3. Design of a {gamma}-ray analysis system for determination of boron in a patient`s head, during neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Verbakel, W.F.A.R.

    1997-12-01

    Boron Neutron Capture Therapy (BNCT) is a new radiation therapy in which thermal neutron capture by {sup 10}B is used for the selective destruction of a cancer tumour. At the High Flux Reactor (HFR) in Petten, Netherlands, a therapy facility is built for the neutron irradiations. In first instance, patients with a brain tumour will be treated. The doses delivered to the tumour and to the healthy tissue depend on the thermal neutron fluence and on the boron concentrations in these regions. Yet, both concentrations change in time after the administration of the tumour-seeking boron compound. An accurate determination of the patient`s dose requires the knowledge of these time dependent concentrations during the therapy. For this reason, a {gamma}-ray telescope system, together with a reconstruction tool, are developed. Two HPGe-detectors measure the 478 keV prompt {gamma}-rays which are emitted at the boron neutron capture reaction, in a large background of {gamma}-rays and neutrons. By using the detectors in a telescope configuration, only {gamma}-rays emitted by a small specific region are detected. The best shielding of the detectors is obtained by performing the measurements through a small hole in the iron roof. A reconstruction tool is developed to calculate absolute boron concentrations using the measured boron {gamma}-ray detection rates. Besides the boron {gamma}-rays, a large component of 2.2 MeV {gamma}-rays emitted at thermal neutron capture in hydrogen is measured. Since the hydrogen distribution is almost homogeneous over the head, this component can serve as a measure of the total number of thermal neutrons in the observed volume. By using the hydrogen {gamma}-line for normalisation of the boron concentration, the reconstruction tool eliminates the greater part of the influence of the inhomogeneity of the thermal neutron distribution. MCNP calculations are used as a tool for the optimisation of the detector configuration. Experiments on a head phantom

  4. A novel detector assembly for detecting thermal neutrons, fast neutrons and gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Cester, D., E-mail: davide.cester@gmail.com [Dipartimento di Fisica ed Astronomia dell' Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); Lunardon, M.; Moretto, S. [Dipartimento di Fisica ed Astronomia dell' Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Nebbia, G. [INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Pino, F. [Dipartimento di Fisica ed Astronomia dell' Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); Sajo-Bohus, L. [Dipartimento di Fisica ed Astronomia dell' Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); Laboratorio de Fisica Nuclear, Universidad Simon Bolivar, Apartado 89000, 1080 A Caracas (Venezuela, Bolivarian Republic of); Stevanato, L.; Bonesso, I.; Turato, F. [Dipartimento di Fisica ed Astronomia dell' Università di Padova, Via Marzolo 8, I-35131 Padova (Italy)

    2016-09-11

    A new composite detector has been developed by combining two different commercial scintillators. The device has the capability to detect gamma rays as well as thermal and fast neutrons; the signal discrimination between the three types is performed on-line by means of waveform digitizers and PSD algorithms. This work describes the assembled detector and its discrimination performance to be employed in the applied field.

  5. A novel detector assembly for detecting thermal neutrons, fast neutrons and gamma rays

    International Nuclear Information System (INIS)

    Cester, D.; Lunardon, M.; Moretto, S.; Nebbia, G.; Pino, F.; Sajo-Bohus, L.; Stevanato, L.; Bonesso, I.; Turato, F.

    2016-01-01

    A new composite detector has been developed by combining two different commercial scintillators. The device has the capability to detect gamma rays as well as thermal and fast neutrons; the signal discrimination between the three types is performed on-line by means of waveform digitizers and PSD algorithms. This work describes the assembled detector and its discrimination performance to be employed in the applied field.

  6. Results on Neutron and Gamma Irradiation of Electrolytic Tilmeters

    International Nuclear Information System (INIS)

    Calderon, A.; Calvo, E.; Figueroa, C. F.; Martinez-Rivero, C.; Matorras, F.; Rodrigo, T.; Vila, I.; Virto, A. L.; Alberdi, J.; Arce, P.; Barcala, J. M.; Fernando, A.; Fuentes, J.; Josa, M. I.; Luque, J. M.; Molinero, A.; Navarrate, J.; 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, an neutrons, up to a maximum fluence 1.5x10''14 cm''2. The effect of the irradiation on their performance is discussed. (Author) 19 refs

  7. The A.R.L. whole body monitor

    International Nuclear Information System (INIS)

    Kotler, L.H.

    1990-02-01

    This report describes a Whole Body Monitor based on four uncollimated NaI(Tl) detectors in a static geometry in use at the Australian Radiation Laboratory. A detailed discussion is presented on the methodology used to estimate the detector efficiency for any arbitrary source whose shape can be described analytically. This procedure is valid for photon emitters in the range 120 keV to 2.6 MeV. By the use of simple geometric models, this approach is applied to the whole body as well as for certain internal organs. For lower photon energies, a discussion of methods using NaI(Tl) detectors to detect in-vivo sources by analysis of pulse-height spectra, is presented. In addition, the application of the Whole Body Monitor in the study of human calcium metabolism, using the tracer 47 Ca is described. Results of measurments on the natural activity of possible candidates for components of the concrete base of the Whole Body Monitor are presented. 74 refs., 22 tabs., 40 figs

  8. Spatial and energy distributions of skyshine neutron and gamma radiation from nuclear reactors on the ground-air boundary

    Energy Technology Data Exchange (ETDEWEB)

    Orlov, Y.; Netecha, M.E.; Vasiliev, A.P.; Avaev, V.N.; Vasiliev, G.A. [Research and Development Institute of Power Engineering, Moscow (Russian Federation); Zelensky, D.I.; Istomin, Y.L.; Cherepnin, Y.S. [Institute of Atomic Energy of the National Nuclear Center of the Republic of Kazakhstan, Semipalatinsk-21 (Kazakhstan); Nomura, Y. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2000-03-01

    A set of measurements on skyshine radiation was conducted at two special research reactors. A broad range of detectors was used in the measurements to record neutron and gamma radiations. Dosimetric and radiometric field measurements of the neutrons and gamma quanta of the radiation scattered in the air were performed at distances of 50 to 1000 m from the reactor during different weather conditions. The neutron spectra in the energy range of 1 eV to 10 MeV and the gamma quanta spectra in the range of 0.1-10 MeV were measured. (author)

  9. Tidal heating and mass loss in neutron star binaries - Implications for gamma-ray burst models

    Science.gov (United States)

    Meszaros, P.; Rees, M. J.

    1992-01-01

    A neutron star in a close binary orbit around another neutron star (or stellar-mass black hole) spirals inward owing to gravitational radiation. We discuss the effects of tidal dissipation during this process. Tidal energy dissipated in the neutron star's core escapes mainly as neutrinos, but heating of the crust, and outward diffusion of photons, blows off the outer layers of the star. This photon-driven mass loss precedes the final coalescence. The presence of this eject material impedes the escape of gamma-rays created via neutrino interactions. If an e(+) - e(-) fireball, created in the late stages of coalescence, were loaded with (or surrounded by) material with the mean column density of the ejecta, it could not be an efficient source of gamma-rays. Models for cosmologically distant gamma-rays burst that involve neutron stars must therefore be anisotropic, so that the fireball expands preferentially in directions where the column density of previously blown-off material is far below the spherically averaged value which we have calculated. Some possible 'scenarios' along these lines are briefly discussed.

  10. Nuclear structure studies on 178Hf by means of neutron induced gamma and electron spectroscopy

    International Nuclear Information System (INIS)

    Al Mamun Imtiazul Haque.

    1985-01-01

    By means of thermal and epithermal neutron captures the nucleus 178 Hf was studied. With high-resolution spectrometers the gamma transitions and conversion electrons were measured. By the found energies, intensities, and multipolarities the level scheme of 178 Hf could be essentially improved and extended. Totally 270 secondary (from 600 gamma lines) and 39 primary gamma transitions were used in order to establish the level scheme with 66 levels in 18 rotational bands. For this 92% of all gamma intensities were used. Several new rotational bands were established. By improved gamma energies the level scheme below 2 MeV for spins between 0 and 6 is well confirmed. Moreover by the resolution of several multiplets the decay structure of the levels could be explained. The thermal neutron capture state results from the primary gamma transitions to Q n =7626.34 (23) keV. Electrical monopole transitions from several states were studied in order to determine the X(E0/E2) values. (orig./HSI) [de

  11. Whole-body monitoring: Goiania case, Brazil

    International Nuclear Information System (INIS)

    Oliveira, C.A.N. de; Lourenco, M.C.; Dantas, B.M.; Lucena, E.A. de; Becker, P.H.B.

    1988-01-01

    Due to the radiological Cs accident in Goiania, Goias in September 1987, it became necessary to evaluate internal contamination levels of: individuals from the general public that for any reason had direct or indirect involvement with the radioactive source (group 1); occupationally involved persons (group 2). For each of these groups, procedures of whole body monitoring were developped. In order to attend group 1 individuals, the IRD/CNEN installed a whole body unit in the INAMPS General Hospital of Goiania in 11.08.87, which was later transferred to 121, 57 street, Central Sector in Goiania in 2.06.88. In this unit 547 people were monitored, 356 from group 1 and 241 from group 2, until 04.13.88. In the IRD whole body counter installation, 194 individuals were counted, 185 from group 2 and 9 from group 1. The frequency of monitoring of each individual was stablished according to the Cs activity present in the body or to the job that will be done. Some body burden activity curves for Cs 137 as a function of the time elapsed from the first measurement, are presented. There people from group 1 were measured in both counters, the IRD and the Goiania ones. The values obtained in both installations are compatible with the body activity X time curve. (author) [pt

  12. Effect of superlarge dose of gamma radiation on the rat cerebral cortex (ultrastructural aspects)

    International Nuclear Information System (INIS)

    Abdrakhmanov, A.A.; AN Kazakhskoj SSR, Alma-Ata

    1988-01-01

    Puberal Wistar line mall rats (180-210 g) were subjected to single whole-body gamma irradiation with 150 Gy dose and 75 Gy/min dose rate. Electron-microscopic investigation into dynamics of sensory-motor cortex ultrastructural changes during 24 hours after irradiation is conducted. Along with destructive changes compensator-reduction processes are developed in brain tissue at this period. Already during the first hours after irradiation the neutron ultrastructure change dynamics has been determined, alongside with direct radiation effect, by indirect effects juries of neuroglia and microcirculatory channel

  13. Effect of superlarge dose of gamma radiation on the rat cerebral cortex (ultrastructural aspects)

    Energy Technology Data Exchange (ETDEWEB)

    Abdrakhmanov, A A

    1988-06-01

    Puberal Wistar line mall rats (180-210 g) were subjected to single whole-body gamma irradiation with 150 Gy dose and 75 Gy/min dose rate. Electron-microscopic investigation into dynamics of sensory-motor cortex ultrastructural changes during 24 hours after irradiation is conducted. Along with destructive changes compensator-reduction processes are developed in brain tissue at this period. Already during the first hours after irradiation the neutron ultrastructure change dynamics has been determined, alongside with direct radiation effect, by indirect effects juries of neuroglia and microcirculatory channel.

  14. Simulation of e-{gamma}-n targets by FLUKA and measurement of neutron flux at various angles for accelerator based neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Patil, B.J., E-mail: bjp@physics.unipune.ernet.i [Department of Physics, University of Pune, Pune 411 007 (India); Chavan, S.T.; Pethe, S.N.; Krishnan, R. [SAMEER, IIT Powai Campus, Mumbai 400 076 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411 007 (India); Dhole, S.D., E-mail: sanjay@physics.unipune.ernet.i [Department of Physics, University of Pune, Pune 411 007 (India)

    2010-10-15

    A 6 MeV Race track Microtron (an electron accelerator) based pulsed neutron source has been designed specifically for the elemental analysis of short lived activation products where the low neutron flux requirement is desirable. The bremsstrahlung radiation emitted by impinging 6 MeV electron on the e-{gamma} primary target, was made to fall on the {gamma}-n secondary target to produce neutrons. The optimisation of bremsstrahlung and neutron producing target along with their spectra were estimated using FLUKA code. The measurement of neutron flux was carried out by activation of vanadium and the measured fluxes were 1.1878 x 10{sup 5}, 0.9403 x 10{sup 5}, 0.7428 x 10{sup 5}, 0.6274 x 10{sup 5}, 0.5659 x 10{sup 5}, 0.5210 x 10{sup 5} n/cm{sup 2}/s at 0{sup o}, 30{sup o}, 60{sup o}, 90{sup o}, 115{sup o}, 140{sup o} respectively. The results indicate that the neutron flux was found to be decreased as increase in the angle and in good agreement with the FLUKA simulation.

  15. Fast neutron and gamma-ray spectra measurements with a NE-213 spectrometer in the FNG Copper Benchmark Experiment

    International Nuclear Information System (INIS)

    Klix, Axel; Angelone, Maurizio; Fischer, Ulrich; Pillon, Mario

    2016-01-01

    Highlights: • Fast neutron and gamma-ray spectra were measured in a copper assembly irradiated with DT neutrons. • The results were compared with MCNP calculations. • Primary aim was to provide experimental data for checking and validation of nuclear data evaluations of copper. - Abstract: A neutronics benchmark experiment on a pure Copper assembly was performed at the Frascati Neutron Generator. The work aimed at testing of recent nuclear data libraries. This paper focuses on the measurement of fast neutron and gamma-ray flux spectra in the Copper assembly under DT neutron irradiation in two selected positions with a spectrometer based on the organic liquid scintillator NE-213. The measurement results were compared with Monte Carlo radiation transport calculations using MCNP and nuclear data from the JEFF-3.1.1 library. Calculations have been done with Cu data from JEFF-3.1.1, JEFF-3.2, FENDL-3 and ENDF/B-7.0. Discrepancies appear in the intermediate neutron energy range between experiment and calculation. Large discrepancies were observed in the gamma-ray spectra calculated with JEFF-3.2.

  16. Fast neutron and gamma-ray spectra measurements with a NE-213 spectrometer in the FNG Copper Benchmark Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Klix, Axel, E-mail: axel.klix@kit.edu [Karlsruhe Institute of Technology, Institute for Neutron Physics and Reactor Technology Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Angelone, Maurizio [ENEA Dipartimento Fusione e Tecnologie per la Sicurezza Nucleare, C.R. Frascati, via E. Fermi 45, 00044 Frascati (Italy); Fischer, Ulrich [Karlsruhe Institute of Technology, Institute for Neutron Physics and Reactor Technology Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Pillon, Mario [ENEA Dipartimento Fusione e Tecnologie per la Sicurezza Nucleare, C.R. Frascati, via E. Fermi 45, 00044 Frascati (Italy)

    2016-11-01

    Highlights: • Fast neutron and gamma-ray spectra were measured in a copper assembly irradiated with DT neutrons. • The results were compared with MCNP calculations. • Primary aim was to provide experimental data for checking and validation of nuclear data evaluations of copper. - Abstract: A neutronics benchmark experiment on a pure Copper assembly was performed at the Frascati Neutron Generator. The work aimed at testing of recent nuclear data libraries. This paper focuses on the measurement of fast neutron and gamma-ray flux spectra in the Copper assembly under DT neutron irradiation in two selected positions with a spectrometer based on the organic liquid scintillator NE-213. The measurement results were compared with Monte Carlo radiation transport calculations using MCNP and nuclear data from the JEFF-3.1.1 library. Calculations have been done with Cu data from JEFF-3.1.1, JEFF-3.2, FENDL-3 and ENDF/B-7.0. Discrepancies appear in the intermediate neutron energy range between experiment and calculation. Large discrepancies were observed in the gamma-ray spectra calculated with JEFF-3.2.

  17. Evaluation of safe use of 188Re-HEDP comparing urine data and whole body counting in gamma camera

    International Nuclear Information System (INIS)

    Paolino, Andrea; Teran, Mariella; Savio, Eduardo; Coppe, Fatima; Lopez, Andrea; Hermida, Juan C.; Gaudiano, Javier

    2008-01-01

    Cancer is the second more frequent cause of death, after cardiovascular disease, in developing countries. Most of adult patients with neoplasms will develop skeletal metastases that can lead to progressive pain. 188 Re emits both beta particles suitable for therapy and a gamma ray (155 keV), adequate for diagnostic imaging in order to verify localization in the pain areas associated to metastatic process. The aim of this work was to correlate 188 Re-HEDP dose estimations using biological samples and direct measures. All the patients had breast or prostate cancer, with bone metastases. Each patient received a tracer dose of 185 MBq of radiopharmaceutical. Urine samples were collected at 0-1, 1-2, 2-4 and, 4-6 hours post administration, and measured in dose calibrator. Whole body counts were acquired using a camera without collimator, window centered at 155 KeV, matrix 256 x 256, during 60 seconds. Data were obtained at 1 and 6 hours post administration with the patient in sitting position at 2 meter from the detector. Percentage of injected dose was calculated both for urine samples and image for each patient. The number of disintegrations was determined for organs in which higher concentration of activity was observed: those involved in the excretion, red marrow and the reminder of the body. Total doses were estimated using OLINDA/EXM software. Conclusions: Data showed that the organs chosen as more compromised during the tracer dose procedure received very low effective doses. A good correlation between calculations performed both for image and urine samples was obtained. Safety of the radiopharmaceutical was also verified using this method. (author)

  18. Energies and Yields of Prompt Gamma Rays from Fragments in Slow-Neutron Induced Fission of 235U

    Energy Technology Data Exchange (ETDEWEB)

    Albinsson, H [Chalmers Univ. of Technology, Goeteborg (SE)

    1971-04-15

    Measurements were made on the gamma radiation emitted from fission fragments in slow-neutron induced fission of 235U. The fragments were detected with solid state detectors of the surface barrier type and the gamma radiation with a Nal(Tl) scintillator. Mass selection was used so that the gamma radiation could be measured as a function of fragment mass. Time discrimination between the fission gammas and the prompt neutrons released in the fission process was employed to reduce the background. The gamma radiation emitted during different time intervals after the fission event was studied with the help of a collimator, the position of which was changed along the path of the fission fragments. In this way it was possible to select various collimator settings and let gamma radiation of different half-lives be enhanced. Gamma-ray energy spectra from these time components were then recorded as function of mass. The spectrum shape differed greatly depending on the half-life of the radiation and the fragment from which it was emitted. The results of the present measurements were discussed in the light of existing fission models, and comparisons were made with prompt gamma-ray and neutron data from other fission experiments

  19. Energies and Yields of Prompt Gamma Rays from Fragments in Slow-Neutron Induced Fission of 235U

    International Nuclear Information System (INIS)

    Albinsson, H.

    1971-04-01

    Measurements were made on the gamma radiation emitted from fission fragments in slow-neutron induced fission of 235 U. The fragments were detected with solid state detectors of the surface barrier type and the gamma radiation with a Nal(Tl) scintillator. Mass selection was used so that the gamma radiation could be measured as a function of fragment mass. Time discrimination between the fission gammas and the prompt neutrons released in the fission process was employed to reduce the background. The gamma radiation emitted during different time intervals after the fission event was studied with the help of a collimator, the position of which was changed along the path of the fission fragments. In this way it was possible to select various collimator settings and let gamma radiation of different half-lives be enhanced. Gamma-ray energy spectra from these time components were then recorded as function of mass. The spectrum shape differed greatly depending on the half-life of the radiation and the fragment from which it was emitted. The results of the present measurements were discussed in the light of existing fission models, and comparisons were made with prompt gamma-ray and neutron data from other fission experiments

  20. Improvement of measuring techniques with whole-body and partial-body counters

    International Nuclear Information System (INIS)

    Anon

    1998-01-01

    Mathematical simulation methods have been applied for optimizing and standardizing the calibration of whole-body and partial-body counters for any nuclide accumulation in the human body. (orig./CB) [de

  1. Comparison of neutron and gamma irradiation effects on KU1 fused silica monitored by electron paramagnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Bravo, D. [Department Fisica de Materiales, Universidad Autonoma de Madrid, E-28049 Madrid (Spain)], E-mail: david.bravo@uam.es; Lagomacini, J.C. [Department Fisica de Materiales, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Leon, M.; Martin, P. [Materiales para Fusion, CIEMAT, Avda. Complutense 22, E-28040 Madrid (Spain); Martin, A. [Department Fisica e Instalaciones, ETS Arquitectura UPM, E-28040 Madrid (Spain); Lopez, F.J. [Department Fisica de Materiales, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Ibarra, A. [Materiales para Fusion, CIEMAT, Avda. Complutense 22, E-28040 Madrid (Spain)

    2009-06-15

    Electron paramagnetic resonance (EPR) studies have been carried out on KU1 fused silica irradiated with neutrons at fluences 10{sup 21} and 10{sup 22} n/m{sup 2}, and gamma-ray doses up to 12 MGy. The effects of post-irradiation thermal annealing treatments, up to 850 deg. C, have also been investigated. Paramagnetic oxygen-related defects (POR and NBOHC) and E'-type defects have been identified and their concentration has been measured as a function of neutron fluence, gamma dose and post-irradiation annealing temperature. It is found that neutrons at the highest fluence generate a much higher concentration of defects (mainly E' and POR, both at concentrations about 5 x 10{sup 18} spins/cm{sup 3}) than gamma irradiations at the highest dose (mainly E' at a concentration about 4 x 10{sup 17} spins/cm{sup 3}). Moreover, for gamma-irradiated samples a lower treatment temperature (about 400 deg. C) is required to annihilate most of the observed defects than for neutron-irradiated ones (about 600 deg. C)

  2. A shielding chamber for the Rossendorf whole-body counter; Eine Abschirmkammer fuer den Rossendorfer Ganzkoerperzaehler

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, Stephan; Loehnert, Daniela [VKTA - Strahlenschutz, Analytik und Entsorgung Rossendorf e.V., Dresden (Germany).; Schreiber, Wolfgang [Ingenieurbedarf G. Schoene und W. Schreiber GmbH, Radeberg (Germany)

    2017-08-01

    A large part of radionuclides to be evaluated in the frame of incorporation monitoring are gamma emitter that can be directly measured (in vivo). In order to reach the required detection limits for the relevant radionuclides in the short measuring time high effort is necessary for the shielding of natural radioactivity. The contribution describes planning, construction and installation of the shielding chamber for the new in vivo whole body counter in Rossendorf. First experiences and preliminary results are discussed.

  3. Dependence of the neutron-gamma log on the porosity of Malmian limestones from the central part of the Nida Trough

    International Nuclear Information System (INIS)

    Szczerba, A.

    1974-01-01

    Results of correlation-regression analysis of the relationship of the prosity Kp to the relative intensity of neutron-induced gamma radiation dIng are reviewed. The geophysical results and laboratory tests of Malmian carbonate rocks from 10 boreholes from the central part of the Nida trough have been utilized to study this relationship. The regression equation dIng=∫(Kp) and the nomogram to determine the porosity Kp on the basis of neutron-gamma log or neutron-gamma and gamma logs, when the correction for the content is to be considered, have been also presented. (author)

  4. The assessment of whole body bone SPECT in oncology

    International Nuclear Information System (INIS)

    Scortechini, Shonika

    2009-01-01

    Full text: Objectives: To assess the significance and practicability of oncology whole body bone SPECT as part of the standard skeletal survey and its impact on the traditional planar whole body bone imaging protocol. Method: Three consenting oncology patients were injected with a standard adult dose of Tc-99m MOP. Delayed Imaging of whole body sweep and SPECT acquisitions were performed on a Siemens Symbia T6. The patient was positioned supine with arms down with a SPECT scan length covering vortex to thighs. SPECT data was reconstructed and a single whole body zipped file created. Normal SPECT slices along with a cine/MIP of the zipped data were created for review. Results: Both image data sets were reviewed to assess if SPECT provided any further diagnostic clinical information not apparent in planer imaging. In our limited review, whole body SPECT did not add extra value to the planar whole body scans performed; it did however demonstrate vertebral involvement with greater resolution. The processing software and system limitations in seamlessly knitting data sets (creating image artefacts) was a major limiting factor in not pursuing further studies. Conclusion: Both imaging techniques offer differing advantages and limitations, however due to image artefact in the triple knitted SPECT approach with current software technology, it cannot be substituted for whole body imaging at this time.

  5. EPR dosimetry in a mixed neutron and gamma radiation field.

    Science.gov (United States)

    Trompier, F; Fattibene, P; Tikunov, D; Bartolotta, A; Carosi, A; Doca, M C

    2004-01-01

    Suitability of Electron Paramagnetic Resonance (EPR) spectroscopy for criticality dosimetry was evaluated for tooth enamel, mannose and alanine pellets during the 'international intercomparison of criticality dosimetry techniques' at the SILENE reactor held in Valduc in June 2002, France. These three materials were irradiated in neutron and gamma-ray fields of various relative intensities and spectral distributions in order to evaluate their neutron sensitivity. The neutron response was found to be around 10% for tooth enamel, 45% for mannose and between 40 and 90% for alanine pellets according their type. According to the IAEA recommendations on the early estimate of criticality accident absorbed dose, analyzed results show the EPR potentiality and complementarity with regular criticality techniques.

  6. Distributions of neutron and gamma doses in phantom under a mixed field

    International Nuclear Information System (INIS)

    Beraud-Sudreau, E.

    1982-06-01

    A calculation program, based on Monte Carlo method, allowed to estimate the absorbed doses relatives to the reactor primary radiation, in a water cubic phantom and in cylindrical phantoms modelized from tissue compositions. This calculation is a theoretical approach of gamma and neutron dose gradient study in an animal phantom. PIN junction dosimetric characteristics have been studied experimentally. Air and water phantom radiation doses measured by PIN junction and lithium 7 fluoride, in reactor field have been compared to doses given by dosimetry classical techniques as tissue equivalent plastic and aluminium ionization chambers. Dosimeter responses have been employed to evaluate neutron and gamma doses in plastinaut (tissue equivalent plastic) and animal (piglet). Dose repartition in the piglet bone medulla has been also determined. This work has been completed by comparisons with Doerschell, Dousset and Brown results and by neutron dose calculations; the dose distribution related to lineic energy transfer in Auxier phantom has been also calculated [fr

  7. Synergistic interaction between the neutron and gamma radiation on LACA mice hemopoietic stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Xu, H

    1982-02-01

    Based on the radiation action dual theory of DNA single and double strand breaks, a hypothetical RBE mathematical model for the effect of the mixed radiation of neutron and gamma rays on LACA mice hemopoietic stem cells was formulated. In comparison of the RBE values of different ratio of neutron and gamma-ray mixed radiation with their theoretical additive RBE values, the preliminary impression is that the mixed radiation is more effective than that of the theoretical additive effect. It seems that the existence of synergist in the mixed radiation might be valid.

  8. Neutron-gamma discrimination based on bipolar trapezoidal pulse shaping using FPGAs in NE213

    Energy Technology Data Exchange (ETDEWEB)

    Esmaeili-sani, Vahid, E-mail: vaheed_esmaeely80@yahoo.com [Department of Nuclear Engineering and Physics, Amirkabir University of Technology, P.O. Box 4155-4494, Tehran (Iran, Islamic Republic of); Moussavi-zarandi, Ali; Akbar-ashrafi, Nafiseh; Boghrati, Behzad; Afarideh, Hossein [Department of Nuclear Engineering and Physics, Amirkabir University of Technology, P.O. Box 4155-4494, Tehran (Iran, Islamic Republic of)

    2012-12-01

    A technique employing neutron-gamma pulse shape discrimination (PSD) system that overcomes pile up limitations of previous methods to distinguish neutrons from gammas in scintillation detectors is described. The output signals of detectors were digitized and processed with a data acquisition system based on bipolar trapezoidal pulse shaping using Field programmable gate arrays (FPGA). FPGAs are capable of doing complex discrete signal processing algorithms with clock rates above 100 MHz. Their low cost, ease of use and selected dedicated hardware make them an ideal option for spectrometer systems.

  9. Clinical evaluation of exercise thallium-201 whole body scintigraphy in ischemic heart disease

    International Nuclear Information System (INIS)

    Kaneko, Kenzo; Watanabe, Yoshihiko; Kondo, Takeshi

    1985-01-01

    To evaluate whole body distribution and kinetics of Thallium-201 at exercise and redistribution, whole body scintigraphy (WB-S) was performed on 12 normal subjects (N), 19 patients with angina pectoris (AP) and 18 patients with old myocardial infarction (MI). WB-S was obtained using a gamma camera OMEGA 500 and analized by ADAC System IV. We estimated the following parameters from WB-S; 1) %Distribution (%D): the ratio of whole body counts to organ counts 2) washout rate (WR) in each organ. %D of the heart in N, AP and MI was similar at rest and exercise. At exercise, %D of the lung and the liver decreased and %D of thighs increased remarkably than at rest. At supine exercise, the lung indicated high %D and thinghs indicated low %D compared with at upright exercise. WR of the heart in AP and MI was significantly lower than in N (p<0.005, p<0.01) and further decreased proportionally to the number of stenotic coronary arteries and related to the ischemic ST depression of exercise ECG. WR of the heart was not correlation with pressure rate product and this finding suggested that WR of the heart was not prescribed by the tolerance of exercise but related to coronary flow at exercise a certain degree. WR of the lung in MI was significantly higher (p<0.025) and WR of thighs in AP and MI was significantly lower (p<0.025, p<0.05) compared with N. (author)

  10. The application of factor analysis for whole body gamma spectra work up

    Energy Technology Data Exchange (ETDEWEB)

    Ragan, P; Fueloep, M [Inst. of Preventive and Clinical Medicine, 83301 Bratislava (Slovakia). Dept. of Radiation Hygiene; Krnac, S [Slovak Technical Univ., 81219 Bratislava (Slovakia). Dept. of Nuclear Physics and Technology

    1996-12-31

    The results of whole body (WB) counting with small high purity germanium detector were presented. The scaling confirmation factor analysis (SCFA) method based on factorization of the response operator is very sensitive and for this application suitable method how to decrease limits of detection. The minimal detectable activity (MDA, for counting time of person 7200 s, background 58600 s and 99% confidence level) of detector usually used in our laboratory for WB counting (relative efficiency 61.8%) 18.5 Bq and MDA for the SCFA method for small detector 17.9 are very close. The use of SCFA method improves the sensitivity (MDA) by factor of 4.1 and the small detector is comparable in sensitivity with the larger one (J.K). 4 tabs., 5 figs., 3 refs.

  11. Angular distribution of gamma rays from the fission of {sup 235}U induced by 14-MeV neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Jeki, L; Kluge, G; Lajtai, A [Central Research Institute for Physics, Hungarian Academy of Sciences (Hungary)

    1969-12-15

    Experiments are reported which were performed to study the angular distribution of the gamma radiation following fast-neutron-induced nuclear fission. The investigations were, in particular, focussed on the influence which the angular momentum imparted to the compound nucleus by the fast neutrons has on the angular distribution of the {gamma}-rays. The fission of {sup 235}U is induced by 14-MeV-energy neutrons from the T(d, n) {alpha} reaction. The fission fragments are detected by a gas-scintillation counter filled with a mixture of Ar and Ni gases, the {gamma}-rays by 5 cm x 5 cm Nal(Tl) crystal with an energy threshold of 120 keV. The intensity of the {gamma}-rays is measured at 90 deg. and 174 deg. to the direction of fragment motion. The flight times of fission neutrons and {gamma}-rays are measured with a 20-ns overlap-type time-to-pulse height converter while the background was covered simultaneously with another converter delayed with respect to the former. The signals from both converters are analysed by a multichannel analyser with divisible memory. The flight path, which is chosen to be about 70 cm, makes it possible to separate the neutron from the gamma counts. The geometry is designed to keep the direction of the outflying fission fragments nearly the same as that of the incident fast neutrons. In this way the angular momenta of the fast neutrons are normal to the flight path of the fragments. The measured gamma intensities are extrapolated to 180 deg on a computer using Strutinski's formula n({theta}) {approx} 1 + B sin {theta}. On transformation of the measured data from the laboratory system to the system of fragments the anisotropy is found to be A = I(180 deg.)/I (90 deg.) = 1.33 {+-} 0.05. The main angular momentum of fission fragments is calculated from the anisotropy as 15 (h/2{pi}) units. As compared with the thermal-neutron-induced fission the present results indicate an additional contribution from the angular momentum of the compound

  12. Advanced CUBIC protocols for whole-brain and whole-body clearing and imaging.

    Science.gov (United States)

    Susaki, Etsuo A; Tainaka, Kazuki; Perrin, Dimitri; Yukinaga, Hiroko; Kuno, Akihiro; Ueda, Hiroki R

    2015-11-01

    Here we describe a protocol for advanced CUBIC (Clear, Unobstructed Brain/Body Imaging Cocktails and Computational analysis). The CUBIC protocol enables simple and efficient organ clearing, rapid imaging by light-sheet microscopy and quantitative imaging analysis of multiple samples. The organ or body is cleared by immersion for 1-14 d, with the exact time required dependent on the sample type and the experimental purposes. A single imaging set can be completed in 30-60 min. Image processing and analysis can take whole-brain neural activities at single-cell resolution using Arc-dVenus transgenic (Tg) mice. CUBIC informatics calculated the Venus signal subtraction, comparing different brains at a whole-organ scale. These protocols provide a platform for organism-level systems biology by comprehensively detecting cells in a whole organ or body.

  13. Results on Neutron and Gamma Irradiation of Electrolytic Tilmeters

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-01

    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, an neutrons, up to a maximum fluence 1.5x10''14 cm''2. The effect of the irradiation on their performance is discussed. (Author) 19 refs.

  14. Application of Nonnegative Tensor Factorization for neutron-gamma discrimination of Monte Carlo simulated fission chamber’s output signals

    Directory of Open Access Journals (Sweden)

    Mounia Laassiri

    Full Text Available For efficient exploitation of research reactors, it is important to discern neutron flux distribution inside the reactor with the best possible precision. For this reason, fission and ionization chambers are used to measure the neutron field. In these arrays, the sequences of the neutron interaction points in the fission chamber can correctly be identified in order to obtain true neutron energies emitted by nuclei of interest. However, together with the neutrons, gamma-rays are also emitted from nuclei and thereby affect neutron spectra. The originality of this study consists in the application of tensor based blind source separation methods to extract independent components from signals recorded at the fission chamber preamplifier’s output. The objective is to achieve software neutron-gamma discrimination using Nonnegative Tensor Factorization tools. For reasons of nuclear safety, we first simulate the neutron flux inside the TRIGA Mark II Reactor using Monte Carlo methods under Geant4 platform linked to Garfield++. Geant4 simulations allow the fission chamber construction whereas linking the model to Garfield++ permits to simulate drift parameters from the ionization of the filling gas, which is not possible otherwise. Keywords: Fission chamber (FC, Geant4, Garfield++, Neutron-gamma discrimination, Nonnegative Tensor Factorization (NTF

  15. Device for characterization of fissile materials comprising at least a neutron detector embedded inside a scintillator for gamma radiation detection

    International Nuclear Information System (INIS)

    Bernard, P.; Dherbey, J.R.; Bosser, R.; Berne, R.

    1989-01-01

    Fissile materials, for instance in radioactive wastes, are characterized by measurement of prompt and delayed neutrons and gamma radiation from induced fission by a neutron source. Gamma radiation is detected with a scintillation detector associated to a photomultiplier, the scintillation material is at the same time a moderator for thermalization of fast neutrons emitted by the neutron source and also of neutrons from spontaneous fission, (α, n) reactions and neutrons from induced fission in the fissile material. Preferentially the moderator is made of Altustipe (Plexiglas with anthracene as additive) [fr

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

    Science.gov (United States)

    Yastrebinskii, R. N.

    2018-04-01

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

  17. Pulse-shape discrimination of high-energy neutrons and gamma rays in NaI(Tl)

    International Nuclear Information System (INIS)

    Share, G.H.; Kurfess, J.D.; Theus, R.B.

    1978-01-01

    Pulse-shape discrimination can be used to separate neutron and gamma-ray interactions depositing energies up to in excess of 50 MeV in NaI(Tl) crystals. The secondary alpha particles, deuterons and protons produced in the neutron interactions are also resolvable. (Auth.)

  18. Effect of neutron and gamma irradiation on magnetic bubble memories

    International Nuclear Information System (INIS)

    Cambou, B.

    1981-06-01

    Many years of research preceeded the introduction of magnetic bubble memories (M.B.M.) into the memory components market. They are used as bulk storage memories principally for their non volatile characteristics under irradiation. A physical and technological description of MBM is given in the first part of the text together with the results of work on their vulnerability when subjected to irradiation. Permanent damage caused by neutrons and gamma radiation on thin magnetic layers is then studied. A theoretical analysis on the stability of bubbles based on the results of pulsed laser experiments is given. The stability of the information stored in a commercially available MBM subjected to neutron and gamma irradiation (MBM - TIB 203 of 92 kBits, Texas) is described in the last part of the text. The vulnerability thresholds determined for the MBM are too high for them to be used in a radioactive environment with an improved electronic control system [fr

  19. Influence of immunization on serum γ-globulin levels of calves following whole-body X irradiation

    International Nuclear Information System (INIS)

    Koch, F.; Mehlhorn, G.; Neumeister, K.; Johannsen, U.; Panndorf, H.

    1980-01-01

    Calves aged 2.5 to 4 months were whole-body X irradiated with mean lethal doses between 1.2 and 1.7 Gy. The effect of different immunization procedures on the irradiation-induced reaction of the serum gamma globulin levels was studied. Immunization 14 and 21 days before irradiation resulted in obvious stimulation gamma globulin production. After parenteral antigen administration the nearly 2 weeks lasting increase of the gamma globulin level rose in the irradiated animals but declined in the sham-irradiated calves. After a lethal dosis of 1.7 Gy there was a decrease of the gamma globulins 3 weeks post irradiation, at the climax of the radiation syndrome. When 1.5 Gy were used the increase of the gamma globulin concentration was observed also after oral administration of the antigen. The response of the irradiated animals in the secondary reaction of the antibody production was most lear after boosting with homologous bacteria. The stimulating effect of the irradiation on the serum globulin levels after immunization prior to irradiation has been attributed to the reaction of the immunoglobulin-producing system to the release of tissue proteins and antigens, respectively

  20. Calculation of neutron and gamma transport at the FOA:type of problems and calculation methods

    International Nuclear Information System (INIS)

    Lefvert, T.

    1975-11-01

    Protection against the effects of nuclear warfare involves the analysis of the forms of results of a nuclear charge explosion producing neutron and gamma radiation. It brings out problems leading to the calculation of criticality, leakage, and deep transmission. Methods have been developed for various kinds of particle transport problems. Applications to radiation therapy, storage of fissile materials, and fast reactors are discussed. A list (with brief description) of all neutron and gamma transport programmes of the FOA is given. (J.S.)

  1. Response of plasma and urinary uric acid, creatine and creatinine to dietary protein deficiency and/or whole body gamma-irradiation in desert rodent and albino rats

    Energy Technology Data Exchange (ETDEWEB)

    Roushdy, H M; El-Husseini, M; Saleh, F [National Centre for Radiation Research and Technology, Cairo (Egypt)

    1985-01-01

    The effect of whole body gamma-irradiation on the levels of plasma and urinary uric acid, creatine and creatinine was studied in the desert rodent, Psammomys obesus and albino rats subjected to dietary protein deficiency. In albino rats, the levels of uric acid in plasma and urine were higher in the animals kept on high protein diets than in those maintained on non-protein ones. Radiation exposure caused a significant increase in uric acid concentration both in plasma and urine of albino rats, whereas in Psammomys obesus obesus, it exerted a significant drop in uric acid concentration in blood paralleling a marked rise in the daily uric acid excretion in the urine, especially with the high radiation level of 1170 r. Creatinine concentrations in plasma and urine of albino rats were higher than the corresponding values in Psammomys obesus obesus. Radiation exposure in general caused an increase in the creatinine concentration in blood and a decrease in its concentration in urine. Plasma creatine was shown to increase due to the effect of radiation exposure. This runs in parallel with the increase in the excretion of creatine in urine. Creatinuria observed in whole body irradiation is obviously caused by a defect in the ability of skeletal muscle to take up creatine from blood. Such abnormality could be the result of direct damage to the muscle caused by incident radiation.

  2. Response of plasma and urinary uric acid, creatine and creatinine to dietary protein deficiency and/or whole body gamma-irradiation in desert rodent and albino rats

    International Nuclear Information System (INIS)

    Roushdy, H.M.; El-Husseini, M.; Saleh, F.

    1985-01-01

    The effect of whole body gamma-irradiation on the levels of plasma and urinary uric acid, creatine and creatinine was studied in the desert rodent, Psammomys obesus and albino rats subjected to dietary protein deficiency. In albino rats, the levels of uric acid in plasma and urine were higher in the animals kept on high protein diets than in those maintained on non-protein ones. Radiation exposure caused a significant increase in uric acid concentration both in plasma and urine of albino rats, whereas in Psammomys obesus obesus, it exerted a significant drop in uric acid concentration in blood paralleling a marked rise in the daily uric acid excretion in the urine, especially with the high radiation level of 1170 r. Creatinine concentrations in plasma and urine of albino rats were higher than the corresponding values in Psammomys obesus obesus. Radiation exposure in general caused an increase in the creatinine concentration in blood and a decrease in its concentration in urine. Plasma creatine was shown to increase due to the effect of radiation exposure. This runs in parallel with the increase in the excretion of creatine in urine. Creatinuria observed in whole body irradiation is obviously caused by a defect in the ability of skeletal muscle to take up creatine from blood. Such abnormality could be the result of direct damage to the muscle caused by incident radiation

  3. Implementation of neutron-induced gamma-ray spectroscopy in industrial applications

    International Nuclear Information System (INIS)

    Abernethy, D. A.; Lim, C. S.

    2006-01-01

    Full text: Neutron based analytical techniques are commonly used in a wide variety of industrial applications, with new applications continually being found. As a result, despite popular concerns about the harmful health effects of radiation the number of these analysers is increasing. This is because neutron-induced gamma-ray techniques have the capability of combining elemental sensitivity with significant penetrating power, enabling non-intrusive and non-destructive bulk elemental measurements to be averaged over a large volume of material. Neutron induced gamma ray spectroscopy has been developed by several groups, including CSIRO Minerals, for on-line measurement of elemental composition in a range of industrial applications in vessels, pipes and on conveyor belts. Compared to those typically found in a scientific laboratory, conditions in industrial plants differ substantially in a number of ways, such as environmental variability, operator skill and training, and shielding requirements. As a result of these differences, equipment and techniques which are used as a matter of course in a laboratory often have to undergo major modification to render them suitable for use in an industrial context. This paper will discuss some of the factors that have to be considered when deciding such matters with particular emphasis on the implications of radiation safety requirements

  4. Radioactive waste package assay facility. Volume 2. Investigation of active neutron and active gamma interrogation

    International Nuclear Information System (INIS)

    Bailey, M.; Bunce, L.J.; Findlay, D.J.S.; Jolly, J.E.; Parsons, T.V.; Sene, M.R.; Swinhoe, M.T.

    1992-01-01

    Volume 2 of this report describes the theoretical and experimental work carried out at Harwell on active neutron and active gamma interrogation of 500 litre cemented intermediate level waste drums. The design of a suitable neutron generating target in conjunction with a LINAC was established. Following theoretical predictions of likely neutron responses, an experimental assay assembly was built. Responses were measured for simulated drums of ILW, based on CAGR, Magnox and PCM wastes. Good correlations were established between quantities of 235 -U, nat -U and D 2 O contained in the drums, and the neutron signals. Expected sensitivities are -1g of fissile actinide and -100g of total actinide. A measure of spatial distribution is obtainable. The neutron time spectra obtained during neutron interrogation were more complex than expected, and more analysis is needed. Another area of discrepancy is the difference between predicted and measured thermal neutron flux in the drum. Clusters of small 3 He proportional counters were found to be much superior for fast neutron detection than larger diameter counters. It is necessary to ensure constancy of electron beam position relative to target(s) and drum, and prudent to measure the target neutron or gamma output as appropriate. 59 refs., 77 figs., 11 tabs

  5. Presence of neutrons in the low-level background environment estimated by the analysis of the 595.8 keV gamma peak

    Energy Technology Data Exchange (ETDEWEB)

    Anđelić, Brankica; Knežević, David; Jovančević, Nikola; Krmar, Miodrag; Petrović, Jovana; Toth, Arpad; Medić, Žarko; Hansman, Jan

    2017-04-21

    In order to explore possible improvements of the existing techniques developed to estimate the neutron fluence in low-background Ge-spectroscopy systems, gamma spectra were collected by a HPGe detector in the presence of the {sup 252}Cf spontaneous fission neutron source. The spectra were taken with and without a Cd envelope on the detector dipstick, with different thicknesses of plastic used to slow down neutrons. We have analyzed the complex 595.8 keV gamma peak, as well as several more gamma peaks following the neutron interactions in the detector itself and surroundings materials. The investigation shows that some changes of the initial neutron spectra can be monitored by the analysis of the 595.8 keV gamma peak. We have found good agreement in the intensity changes between the long-tail component of the 595.8 keV and the 691 keV gamma peak ({sup 72}Ge(n,n′){sup 72}Ge reaction), usually used for the estimation of the fast neutron fluence. Results also suggest that the thermal neutrons can have a stronger influence on creation of the Gaussian-like part of 595.8 keV peak, than on the 139 keV one following {sup 74}Ge(n,γ){sup 75m}Ge reaction and used in the standard methods (Škoro et al., 1992) [8] for determination of the thermal neutron flux.

  6. Accuracy and borehole influences in pulsed neutron gamma density logging while drilling

    Energy Technology Data Exchange (ETDEWEB)

    Yu Huawei [College of Geo-Resources and Information, China University of Petroleum, Qingdao, Shandong 266555 (China); Center for Engineering Applications of Radioisotopes (CEAR), Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Sun Jianmeng [College of Geo-Resources and Information, China University of Petroleum, Qingdao, Shandong 266555 (China); Wang Jiaxin [Center for Engineering Applications of Radioisotopes (CEAR), Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Gardner, Robin P., E-mail: gardner@ncsu.edu [Center for Engineering Applications of Radioisotopes (CEAR), Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 (United States)

    2011-09-15

    A new pulsed neutron gamma density (NGD) logging has been developed to replace radioactive chemical sources in oil logging tools. The present paper describes studies of near and far density measurement accuracy of NGD logging at two spacings and the borehole influences using Monte-Carlo simulation. The results show that the accuracy of near density is not as good as far density. It is difficult to correct this for borehole effects by using conventional methods because both near and far density measurement is significantly sensitive to standoffs and mud properties. - Highlights: > Monte Carlo evaluation of pulsed neutron gamma-ray density tools. > Results indicate sensitivity of the tool to standoff and mudcake properties. > Accuracy of far spaced detector is better than near spaced.

  7. Accuracy and borehole influences in pulsed neutron gamma density logging while drilling

    International Nuclear Information System (INIS)

    Yu Huawei; Sun Jianmeng; Wang Jiaxin; Gardner, Robin P.

    2011-01-01

    A new pulsed neutron gamma density (NGD) logging has been developed to replace radioactive chemical sources in oil logging tools. The present paper describes studies of near and far density measurement accuracy of NGD logging at two spacings and the borehole influences using Monte-Carlo simulation. The results show that the accuracy of near density is not as good as far density. It is difficult to correct this for borehole effects by using conventional methods because both near and far density measurement is significantly sensitive to standoffs and mud properties. - Highlights: → Monte Carlo evaluation of pulsed neutron gamma-ray density tools. → Results indicate sensitivity of the tool to standoff and mudcake properties. → Accuracy of far spaced detector is better than near spaced.

  8. Whole body scan system based on γ camera

    International Nuclear Information System (INIS)

    Ma Tianyu; Jin Yongjie

    2001-01-01

    Most existing domestic γ cameras can not perform whole body scan protocol, which is of important use in clinic. The authors designed a set of whole body scan system, which is made up of a scan bed, an ISA interface card controlling the scan bed and the data acquisition software based on a data acquisition and image processing system for γ cameras. The image was obtained in clinical experiment, and the authors think it meets the need of clinical diagnosis. Application of this system in γ cameras can provide whole body scan function at low cost

  9. Interaction effect of gamma rays and thermal neutrons on the inactivation of odontoglossum ringspot virus isolated from orchid

    International Nuclear Information System (INIS)

    Mori, Itsuhiko; Inouye, Narinobu.

    1977-01-01

    The effect of gamma rays or thermal neutrons and their interaction effects on the inactivation of the infectivity of Odontoglossum ringspot virus (ORSV) in buffered crude sap of the plant tissue were studied. The inactivation effect of gamma ray on ORSV varied in different ionic strength of the phosphate buffer solutions. Borax enhanced this effect. In interaction effect of gamma and neutron irradiation, irradiation orders, that is, n → γ and γ → n, gave different inactivation pattern. (author)

  10. Neutron and gamma ray calculation for Hiroshima-type atomic bomb

    Energy Technology Data Exchange (ETDEWEB)

    Hoshi, Masaharu; Endo, Satoru; Takada, Jun [Hiroshima Univ. (Japan). Research Inst. for Radiation Biology and Medicine; Iwatani, Kazuo; Oka, Takamitsu; Shizuma, Kiyoshi; Fujita, Shoichiro; Hasai, Hiromi

    1998-03-01

    We looked at the radiation dose of Hiroshima and Nagasaki atomic bomb again in 1986. We gave it the name of ``Dosimetry System 1986`` (DS86). We and other groups have measured the expose dose since 1986. Now, the difference between data of {sup 152}Eu and the calculation result on the basis of DS86 was found. To investigate the reason, we carried out the calculations of neutron transport and neutron absorption gamma ray for Hiroshima atomic bomb by MCNP3A and MCNP4A code. The problems caused by fast neutron {sup 32}P from sulfur in insulator of pole. To correct the difference, we investigated many models and found agreement of all data within 1 km. (S.Y.)

  11. Ionizing/displacement synergistic effects induced by gamma and neutron irradiation in gate-controlled lateral PNP bipolar transistors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chenhui, E-mail: wangchenhui@nint.ac.cn [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O. Box 69-10, Xi’an 710024 (China); Chen, Wei; Yao, Zhibin; Jin, Xiaoming; Liu, Yan; Yang, Shanchao [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O. Box 69-10, Xi’an 710024 (China); Wang, Zhikuan [State Key Laboratory of Analog Integrated Circuit, Chongqing 400060 (China)

    2016-09-21

    A kind of gate-controlled lateral PNP bipolar transistor has been specially designed to do experimental validations and studies on the ionizing/displacement synergistic effects in the lateral PNP bipolar transistor. The individual and mixed irradiation experiments of gamma rays and neutrons are accomplished on the transistors. The common emitter current gain, gate sweep characteristics and sub-threshold sweep characteristics are measured after each exposure. The results indicate that under the sequential irradiation of gamma rays and neutrons, the response of the gate-controlled lateral PNP bipolar transistor does exhibit ionizing/displacement synergistic effects and base current degradation is more severe than the simple artificial sum of those under the individual gamma and neutron irradiation. Enough attention should be paid to this phenomenon in radiation damage evaluation. - Highlights: • A kind of gate-controlled lateral PNP bipolar transistor has been specially designed to facilitate the analysis of ionizing/displacement synergistic effects induced by the mixed irradiation of gamma and neutron. • The difference between ionizing/displacement synergistic effects and the simple sum of TID and displacement effects is analyzed. • The physical mechanisms of synergistic effects are explained.

  12. Investigation of gamma-ray sensitivity of neutron detectors based on thin converter films

    Energy Technology Data Exchange (ETDEWEB)

    Khaplanov, A; Hall-Wilton, R [European Spallation Source, P.O Box 176, SE-22100 Lund (Sweden); Piscitelli, F; Buffet, J-C; Clergeau, J-F; Correa, J; Esch, P van; Ferraton, M; Guerard, B [Institute Laue Langevin, Rue Jules Horowitz, FR-38042 Grenoble (France)

    2013-10-15

    Currently, many detector technologies for thermal neutron detection are in development in order to lower the demand for the rare {sup 3}He gas. Gas detectors with solid thin film neutron converters readout by gas proportional counter method have been proposed as an appropriate choice for applications where large area coverage is necessary. In this paper, we investigate the probability for {gamma}-rays to generate a false count in a neutron measurement. Simulated results are compared to measurement with {sup 10}B thin film prototypes and a {sup 3}He detector. It is demonstrated that equal {gamma}-ray rejection to that of {sup 3}He tubes is achieved with the new technology. The arguments and results presented here are also applicable to gas detectors with converters other than solid {sup 10}B layers, such as {sup 6}Li layers and {sup 10}BF{sub 3} gas.

  13. Guideline of Monte Carlo calculation. Neutron/gamma ray transport simulation by Monte Carlo method

    CERN Document Server

    2002-01-01

    This report condenses basic theories and advanced applications of neutron/gamma ray transport calculations in many fields of nuclear energy research. Chapters 1 through 5 treat historical progress of Monte Carlo methods, general issues of variance reduction technique, cross section libraries used in continuous energy Monte Carlo codes. In chapter 6, the following issues are discussed: fusion benchmark experiments, design of ITER, experiment analyses of fast critical assembly, core analyses of JMTR, simulation of pulsed neutron experiment, core analyses of HTTR, duct streaming calculations, bulk shielding calculations, neutron/gamma ray transport calculations of the Hiroshima atomic bomb. Chapters 8 and 9 treat function enhancements of MCNP and MVP codes, and a parallel processing of Monte Carlo calculation, respectively. An important references are attached at the end of this report.

  14. Assessment of the neutron component in a neutron-gamma field of a californium-252 source

    International Nuclear Information System (INIS)

    Tetteh, G.K.

    1978-12-01

    Experiments have been performed to determine the percentages of the different components in the radiation field of californium-252 which has now some clinical applications. Using Rossi Chambers in conjunction with absorption investigations involving lead and aluminium thimbles, it is observed that the dose rates due to the different components are: neutrons 54%; gammas 30%; betas 16%

  15. Dosimetry of the Embalse nuclear power plant neutron/gamma mixed fields

    International Nuclear Information System (INIS)

    Salas, C.A.

    1990-01-01

    The aim of this work is to describe the method used at the Embalse nuclear power plant for carrying out personal dosimetry of the agents affected to the tasks on the Embalse nuclear power plant neutron-gamma mixed fields. (Author) [es

  16. Improved models for determination of body fat by in vivo neutron activation

    International Nuclear Information System (INIS)

    Cohn, S.; Vaswani, A.; Yasumura, S.; Yuen, K.; Ellis, K.

    1984-01-01

    In the present study, two different models of body composition, based on data obtained by nuclear techniques are used. Total body nitrogen, calcium, and chlorine were obtained by total body neutron activation. Total body chlorine was used to estimate extracellular water, and total body calcium to determine bone mineral and extracellular solids. Total body potassium was measured by whole body counting to obtain the body cell mass. In addition, total body water was measured by the tritium dilution technique. It was found that either model can be used equally well to measure total body fat in normal subjects. Estimation of body fat as the difference between body weight and the sum of total body nitrogen (protein), total body water, and bone ash (model 1) appears to have an advantage over model 2, which uses body cell mass, extracellular water, and extracellular solids, particularly for patients with metabolic disorders. This advantage is partly due to the fact that the parameter protein (total body nitrogen) is less affected in metabolic disorders than the more labile total body potassium. The closely correlated results obtained with the two models based on nuclear measurements support the conclusion that these techniques provide reliable measurements of total body fat

  17. A silicon photomultiplier readout for time of flight neutron spectroscopy with {gamma}-ray detectors

    Energy Technology Data Exchange (ETDEWEB)

    Pietropaolo, A.; Gorini, G. [Dipartimento di Fisica ' ' G. Occhialini' ' and CNISM, Universita Degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano (Italy); Festa, G.; Andreani, C.; De Pascale, M. P.; Reali, E. [Dipartimento di Fisica and Centro NAST, Universita degli Studi di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133, Roma (Italy); Grazzi, F. [Istituto dei Sistemi Complessi-Consiglio Nazionale delle Ricerche, Via Madonna del Piano n.10, I-50019 Sesto Fiorentino, Firenze (Italy); Schooneveld, E. M. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX (United Kingdom)

    2009-09-15

    The silicon photomultiplier (SiPM) is a recently developed photosensor used in particle physics, e.g., for detection of minimum ionizing particles and/or Cherenkov radiation. Its performance is comparable to that of photomultiplier tubes, but with advantages in terms of reduced volume and magnetic field insensitivity. In the present study, the performance of a gamma ray detector made of an yttrium aluminum perovskite scintillation crystal and a SiPM-based readout is assessed for use in time of flight neutron spectroscopy. Measurements performed at the ISIS pulsed neutron source demonstrate the feasibility of {gamma}-detection based on the new device.

  18. Design of hyper-thermal neutron irradiation fields for neutron capture therapy in KUR-heavy water neutron irradiation facility. Mounting of hyper-thermal neutron converter in therapeutic collimator

    International Nuclear Information System (INIS)

    Sakurai, Y.; Kobayashi, T.

    2001-01-01

    Neutron capture therapy (NCP) using thermal neutron needs to improve of depth dose distribution in a living body. Epi-thermal neutron following moderation of fast neutron is usually used for improving of the depth dose distribution. The moderation method of fast neutron, however, gets mixed some of high energy neutron which give some of serious effects to a living body, and involves the difficulty for collimation of thermal neutron to the diseased part. Hyper-thermal neutrons, which are in an energy range of 0.1-3 eV at high temperature side of thermal neutron, are under consideration for application to the NCP. The hyper-thermal neutrons can be produced by up-scattering of thermal neutron in a high temperature material. Fast neutron components in collimator for the NCP reduce on application of the up-scattering method. Graphite at high temperature (>1000k) is used as a hyper-thermal neutron converter. The hyper-thermal neutron converter is planted to mount on therapeutic collimator which is located at the nearest side of patient for the NCP. Total neutron flux, ratio of hyper-thermal neutron to total neutron, and ratio of gamma-ray dose to neutron flux are calculated as a function of thickness of the graphite converter using monte carlo code MCNP-V4B. (M. Suetake)

  19. 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

  20. Portable neutron and gamma-radiation instruments

    International Nuclear Information System (INIS)

    Murray, W.S.; Butterfield, K.B.

    1990-01-01

    This paper reports on the design and building of a smart neutron and gamma-radiation detection systems with embedded microprocessors programmed in the FORTH language. These portable instruments can be battery-powered and can provide many analysis functions not available in most radiation detectors. Local operation of the instruments is menu-driven through a graphics liquid crystal display and hex keypad; remote operation is through a serial communications link. While some instruments simply count particles, others determine the energy of the radiation as well as the intensity. The functions the authors have provided include absolute source-strength determination. Feynmann variance analysis, sequential-probability ratio test, and time-history recording