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1

Gamma and alpha radiation levels in a Basalt High-Level Waste Repository: Potential impact on container corrosion and packing properties  

Microsoft Academic Search

Gamma radiation levels during the containment period and alpha radiation levels in the packing material during the controlled release period were calculated based on the conceptual design of the waste package for a high-level nuclear waste repository in basalt. The maximum gamma dose rate was 250 rad\\/h and the maximum absorbed dose during the containment period was 66 Mrad. The

D. T. Reed; S. D. Bonar; M. F. Weiner

1985-01-01

2

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

PubMed

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

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

2010-01-01

3

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

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

4

Correlation between gamma radiation levels and soil radium concentrations at the Edgemont uranium mill site  

SciTech Connect

The Tennessee Valley Authority's uranium mill in Edgemont, South Dakota, is being decommissioned. Approximately 4 million tons of contaminated tailings, building equipment, and contaminated soil and debris on the mill site will be removed to the disposal site located approximately 3 kilometers to the southeast. To minimize recontamination of cleaned areas, tailings removal will progress from the northwest corner to the southeast corner of the mill site. As specific areas are cleaned, surveys will be conducted to determine if the concentrations of radium-226 in soil are within the limits outlined in 40 CFR, Part 192. Conformance with the criteria will be demonstrated by a gamma survey of the area employing the differential, or delta-measurement, technique. This technique involves fitting the detector with a base and a receptacle for a removable high-density filter. By making measurements with and without the filter in place, a gamma radiation level proportional to the radium-226 concentration in soil can be determined. This paper describes the results obtained in the development of the correlation between the gamma survey measurements and the soil radium concentrations.

Wallace, R.G.; Reed, R.P.; Polehn, J.L.; Wilson, G.T.

1985-01-01

5

gamma-Radiation influences browning, antioxidant activity, and malondialdehyde level of apple juice.  

PubMed

Apple juice was gamma-irradiated at 5 degrees C at doses ranging from 0 to 8.9 kGy and then stored at 5 degrees C for 15 days. Ionizing radiation reduced the browning of apple juice and increased antioxidant activity measured by the ferric-reducing antioxidant power (FRAP) assay. The magnitude of changes increased with radiation dose. The level of malondialdehyde (MDA) measured using the thiobarbituric acid reactive substrates assay increased at radiation doses above 2.67 kGy. The browning of irradiated juices increased during storage at 5 degrees C, but the irradiated juices were still lighter than controls at the end of storage. Differences in FRAP values disappeared during early periods of storage while higher MDA levels were observed in irradiated samples during most of the storage period. Elimination of suspended matter from apple juice did not alter irradiation-induced changes in browning, FRAP, or MDA formation. As compared to irradiation conducted at 5 and 20 degrees C, treatment at -15 degrees C was less effective in reducing browning and in increasing MDA formation but elevated FRAP values. The exclusion of oxygen from juices did not affect the reduction in browning due to irradiation but promoted the increase in FRAP values and decreased the irradiation-induced MDA formation. PMID:11829633

Fan, Xuetong; Thayer, Donald W

2002-02-13

6

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

PubMed

Previously we have shown that growth of melanized fungi is stimulated by low levels of gamma radiation. The goal of this study was to examine the effects of visible light, UV light, and gamma radiation on the energy level (ATP concentration) in melanized Cryptococcus neoformans cells. Melanized C. neoformans cells as well as non-melanized controls were subjected to visible, UV or gamma radiation, and ATP was quantified by measuring the amount of light emitted by the ATP-dependent reaction of luciferase with luciferin. We found that all three forms of radiation led to a reduction in the ATP levels in melanized C. neoformans cells. This points to a universal melanin-related mechanism underlying observation of ATP decrease in irradiated melanized cells. In contrast, in non-melanized cells visible light led to increase in ATP levels; gamma radiation did not cause any changes while UV exposure resulted in some ATP decrease, however, much less pronounced than in melanized cells. PMID:21944206

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

2011-05-07

7

Radiation Exposure of the Population and Indoor Radiation Levels in The Netherlands Caused by Natural gamma Sources.  

National Technical Information Service (NTIS)

An estimate has been made of gamma doses to the population in the Netherlands, caused by natural radiation sources encountered in the environment. Data are given, derived from two independent types of measurements: 1. Exposure/dose rate measurements in th...

H. W. Julius R. Dongen

1985-01-01

8

Assessment of radon concentration and external gamma radiation level in the environs of Narwapahar uranium mine, India and its radiological significance  

Microsoft Academic Search

In the environs of uranium mining, milling and processing facilities and in the uranium mineralized terrain, a little higher\\u000a ambient radon concentration and gamma radiation level may be expected in comparison with natural background. The present study\\u000a gives a brief account of atmospheric radon concentration, gamma absorbed dose rate and radiation dose received by the members\\u000a of public in the

B. K. Rana; R. M. Tripathi; J. S. Meena; S. K. Sahoo; R. Topno; A. K. Shukla; V. D. Puranik

9

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

PubMed Central

This study assesses the level of terrestrial gamma radiation and associated dose rates from the naturally occurring radionuclides 232Th, 238U and 40K in 10 soil samples collected from Thanjavur (Tamil Nadu, India) using ?-ray spectrometry. The activity profile of radionuclides has clearly showed the existence of low level activity in Thanjavur. The geometric mean activity concentrations of 232Th, 238U and 40K is 42.99.4 Bq.kg?1, 14.71.7 Bq.kg?1 and 149.53.1 Bq.kg?1 respectively are derived from all the soil samples studied. The activity concentration of 232Th, 238U and 40K in soil is due to the presence of metamorphic rocks like shale, hornblende-biotite gneiss and quartzofeldspathic gneiss in these areas. Gamma absorbed dose rates in air outdoors were calculated to be in the range between 32 nGy.h?1 and 59.1 nGy.h?1 with an arithmetic mean of 43.3 9 nGy.h?1. This value is lesser than the population weighted world-averaged of 60 nGy.h?1. Inhabitants of Thanjavur are subjected to external gamma radiation exposure (effective dose) ranging between 39.2 and 72.6 ?Sv.y?1 with an arithmetic mean of 53.111 ?Sv.y?1. The values of the external hazard index determined from the soil radioactivity of the study area are less than the recommended safe levels.

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

2010-01-01

10

Gamma radiation field intensity meter  

DOEpatents

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

Thacker, L.H.

1995-10-17

11

GammaRadiation from Granite  

Microsoft Academic Search

It has been reported that measurements of the ionization produced by the gamma-rays from Quincy granite are in excess of the ionization computed from the measured uranium, thorium, and potassium content of the rock by a factor of over two. It was concluded that either the measured radioactive contents were much too low or that a hitherto unknown penetrating radiation

William D. Urry

1948-01-01

12

Radioprotective effect of Haberlea rhodopensis (Friv.) leaf extract on gamma-radiation-induced DNA damage, lipid peroxidation and antioxidant levels in rabbit blood.  

PubMed

Different concentrations of H. rhodopensis total extract (HRE; 0.03, 0.06 and 0.12 g/kg body weight) were injected im, into rabbits 2 h before collecting the blood samples. The whole blood samples were exposed in vitro to 2.0 Gy 60Co gamma-radiation. The radiation-induced changes were estimated by using the chromosome aberration test (CA) and cytokinesis blocked micronucleus assay (CBMN) in peripheral lymphocytes, and by determining the malondialdehyde levels (MDA) in blood plasma and the superoxide dismutase (SOD) and catalase (CAT) activity in erythrocytes. Radiation significantly increased the chromosome aberration and micronuclei frequencies as well as MDA levels and decreased the antioxidant enzyme activity. On the other hand, the HRE pretreatment significantly decreased the CA, MN frequencies and MDA levels and increased the SOD and CAT activity in a concentration dependent manner. The most effective was the highest concentration of HRE (0.12 g/kg body weight). The results suggest that HRE as a natural product with a nantioxidant capacity could play a modulatory role against the cellular damage induced by gamma-irradiation. The possible mechanism involved in the radioprotective potential of HRE is discussed. PMID:23441477

Georgieva, Svetlana; Popov, Borislav; Bonev, Georgi

2013-01-01

13

Portable gamma and neutron radiation dosimeter reader  

Microsoft Academic Search

During the operation of linear accelerators, gamma and neutron radiation is produced. Gamma radiation causes semiconductor degradation. Therefore, it is necessary to replace electronic devices when the maximum allowed dose is reached to ensure reliable operation of the accelerator. Neutron radiation causes soft errors in memories and registers because of Single Event Upsets (SEUs). This may disturb the whole accelerator

Piotr Krasinski; Dariusz Makowski; Bhaskar Mukherjee

2008-01-01

14

Virtual Gamma Ray Radiation Sources through Neutron Radiative Capture  

SciTech Connect

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.

Scott Wilde, Raymond Keegan

2008-07-01

15

Pocket dual Neutron\\/Gamma radiation detector  

Microsoft Academic Search

A pocket radiation detection system has been developed at the INEEL for homeland security applications. It can detect both neutrons and gamma rays instantaneously. This sensor has been designed with an emphasis on compactness' recognizing the widespread need for a radiation detection instrument that could provide both neutron and gamma ray detection in a single, portable unit. It is very

Rahmat Aryaeinejad; David F. Spencer

2003-01-01

16

Pocket dual neutron\\/gamma radiation detector  

Microsoft Academic Search

A pocket radiation detection system has been developed at the Idaho National Engineering and Environmental Laboratory for homeland security applications. It can detect both neutrons and gamma rays instantaneously. This sensor has been designed with an emphasis on compactness, recognizing the widespread need for a radiation detection instrument that could provide both neutron and gamma-ray detection in a single, portable

Rahmat Aryaeinejad; David F. Spencer

2004-01-01

17

Gamma radiation exposure of MCT diode arrays  

Microsoft Academic Search

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

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

2006-01-01

18

Radiation Sterilization and Food Irradiation Using Gamma Radiation  

NASA Astrophysics Data System (ADS)

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

O'Hara, Kevin

2003-03-01

19

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

Microsoft Academic Search

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

Sebastian Fleischer; Rainer Hampel

2006-01-01

20

Leukemogenesis by low-level radiation  

SciTech Connect

Intermittent x-radiation administered in three R doses for ten successive weeks to RAP mice did not increase the incidence of leukemia. A total dose of 100 R (10 R weekly) significantly increased the level. A total dose of 300 R (30 R weekly) increased the incidence of leukemia only slightly but not significantly over that induced by the 100 R total dose. The two leukemogenic doses of x-radiation (100 and 300 R) yielded incidences of leukemia comparable to those following mean doses of perinatal gamma exposure at 200 and 1000 rads. However, continuous lifetime exposure of five successive generations to 30 rads was by far more effective than the higher doses of gamma or x-radiation. In these wide discrepancies between leukemogenic effects of equal low doses of gamma and x-radiation, there are two disparate factors; chronic versus intermittent exposure and the populations at risk; young adult mice versus mice exposed from conception to death. (auth)

Warren, S.; Gates, O.

1975-01-01

21

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

PubMed

Supernovae and gamma ray bursts are exceptionally powerful cosmic events that occur randomly in space and time in our galaxy. Their potential to produce very high radiation levels has been discussed, along with speculation that they may have caused mass extinctions noted from the fossil record. It is far more likely that they have produced radiation levels that, while not lethal, are genetically significant, and these events may have influenced the course of evolution and the manner in which organisms respond to radiation insult. Finally, intense gamma radiation exposure from these events may influence the ability of living organisms to travel through space. Calculations presented in this paper suggest that supernovae and gamma ray bursts are likely to produce sea-level radiation exposures of about I Gy with a mean interval of about five million years and sea-level radiation exposures of about 0.2 Gy every million years. Comets and meteors traveling through space would receive doses in excess of 10 Gy at a depth of 0.02 m at mean intervals of 4 and 156 million years, respectively. This may place some constraints on the ability of life to travel through space either between planets or between planetary systems. Calculations of radiation dose from neutrino radiation are presented and indicate that this is not a significant source of radiation exposure for even extremely close events for the expected neutrino spectrum from these events. PMID:11906138

Karam, P Andrew

2002-04-01

22

Dibasic calcium phosphate dihydrate, USP material compatibility with gamma radiation  

NASA Astrophysics Data System (ADS)

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

Betancourt Quiles, Maritza

23

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

Microsoft Academic Search

Thermal neutron activation analyses were carried out for various space systems components to determine gamma radiation dose rates and food radiation contamination levels. The space systems components selected were those for which previous radiation studies existed. These include manned space vehicle radiation shielding, liquid hydrogen propellant tanks for a Mars mission, and a food supply used as space vehicle radiation

Heriberto Plaza-Rosado

1991-01-01

24

Low-level gamma-ray spectrometry  

Microsoft Academic Search

Low-level gamma-ray spectrometry generally equates to high-sensitivity gamma-ray spectrometry that can be attained by background reduction, selective signal identification, or some combination of both. Various methods for selectively identifying gamma-ray events and for reducing the background in gamma ray spectrometers are given. The relative magnitude of each effect on overall sensitivity and the relative 'cost' for implementing them are given

R L Brodzinski

1991-01-01

25

High range gamma radiation meter  

SciTech Connect

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

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

1986-02-01

26

High range gamma radiation meter  

SciTech Connect

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

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

1985-01-01

27

High range gamma radiation meter  

NASA Astrophysics Data System (ADS)

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

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

1985-10-01

28

Antioxidant power, lipid oxidation, color, and viability of Listeria monocytogenes in beef bologna treated with gamma radiation and containing various levels of glucose.  

PubMed

Ionizing radiation can be used to pasteurize ready-to-eat (RTE) meat products. Thermal processing of RTE meats that contain dextrose results in the production of antioxidants that may interfere with ionizing radiation pasteurization of RTE meat products. Beef bologna was manufactured with dextrose concentrations of 0, 2, 4, 6, and 8%. Antioxidant activity, as measured by the Ferric Reducing Antioxidant Power assay, increased with dextrose concentration but was unaffected by ionizing radiation. Lipid oxidation increased significantly in irradiated bologna (4 kGy) that contained dextrose. Hunter color analysis indicated that the addition of dextrose reduced the ionizing radiation-induced loss of redness (a-value) but promoted the loss of brightness (L-value). The radiation resistance, D10-value, of Listeria monocytogenes that was surface-inoculated onto bologna slices was not affected by dextrose concentration. L. monocytogenes strains isolated from RTE meats after listeriosis outbreaks were utilized. Increased antioxidant activity generated by thermal processing of dextrose in fine emulsion sausages does not present a barrier to radiation pasteurization of RTE meats. However, a high dextrose concentration in combination with gamma irradiation increases lipid oxidation significantly. PMID:12430697

Sommers, Christopher H; Fan, Xuetong

2002-11-01

29

Fluid metabolism changes in the presence of various forms of acute radiation sickness. [Rats, gamma radiation  

Microsoft Academic Search

Acute radiation sickness was induced in rats by 700 to 1000 R doses of gamma radiation. Fluid metabolism was examined 24, 48 and 72 h later. A table is presented to show changes in total extracellular, intracellular, and intravascular fluid levels. One day after irradiation there was a decrease in total fluid content, intracellular, and intravascular fluid, and an increase

N. I. Tsyran; A. A. Sveshnikov; V. S. Nesterenko

1977-01-01

30

Balloon-borne telescope for cosmic gamma radiation  

Microsoft Academic Search

The primary gamma radiation could possibly provide information concerning the origin of the cosmic radiation, because gamma rays are not affected by magnetic fields, which have a very pronounced effect on the nucleonic component of the cosmic radiation. In connection with disturbing effects, mainly due to secondary gamma radiation, a minimum altitude of 45 km is required to observe the

H. Rothermel

1976-01-01

31

Gamma Radiation Doses In Sweden  

SciTech Connect

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

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

2008-08-07

32

Gamma Radiation Doses In Sweden  

NASA Astrophysics Data System (ADS)

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

Almgren, Sara; Barrega?Rd, Lars; Isaksson, Mats

2008-08-01

33

Inspection of cargo containers using gamma radiation  

NASA Astrophysics Data System (ADS)

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

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

1997-02-01

34

Low-level gamma-ray spectrometry  

SciTech Connect

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

Brodzinski, R.L.

1990-10-01

35

Gamma Radiation Tolerance of Magnetic Tunnel Junctions  

NASA Astrophysics Data System (ADS)

Determining the radiation tolerance of magnetic tunnel junctions (MTJ), which are the storage elements of non-volatile magnetoresistive random access memories (MRAM), is important for investigating their potential application in space. In this effort, the effect of gamma radiation on MTJs with MgO tunnel barriers was studied. Experimental and control groups of samples were characterized by ex situ measurements of the magnetoresistive hysteresis loops and I-V curves. The experimental group was exposed to gamma rays from a ^60Co source. The samples initially received a dose of 5.9 Mrad (Si) after which they were again characterized electrically and magnetically. Irradiation was then continued for a cumulative dose of 10 Mrad and the devices re-measured. The result shows no change in magnetic properties such as coercivity or exchange coupling due to irradiation. After correcting for differences in temperature at the time of testing, the tunneling magnetoresistance was also found to be unchanged. Thus, it has been determined that MgO-based MTJs are highly tolerant of gamma radiation, particularly in comparison to silicon field-effect transistors which have been shown to degrade with gamma ray exposure even as low as 100 Krad [Zhiyuan Hu. et al., IEEE trans. on Nucl. Sci., vol. 58, 2011].

Ren, Fanghui; Jander, Albrecht; Dhagat, Pallavi; Nordman, Cathy

2011-10-01

36

Sterilization of teeth by gamma radiation.  

PubMed

Clinical simulations and restorative materials research and development conducted in vitro require the use of large numbers of extracted teeth. The simultaneous need for infection control procedures and minimal alterations of structure and properties of the tissue prompted this study of gamma irradiation as a method to eliminate microbes associated with extracted teeth and their storage solutions. Evaluations of potential change in structure of dentin were conducted in terms of permeability, Fourier transform infrared spectroscopy (FTIR), and optical properties. The dose required for sterilization by gamma irradiation was established by means of a tooth model inoculated with Bacillus subtilis (10(8) organisms/mL). Sterilization occurred at a dose above 173 krad with use of a Cesium (Cs137) radiation source. Gamma irradiation did not affect permeability of crown segments of dentin. A comparative evaluation of the effects of four sterilization methods on dentin disks was based on FTIR and ultraviolet-visible-near infrared (UV/VIS/NIR) spectra before and after sterilization by (1) gamma irradiation; (2) ethylene oxide; (3) dry heat; and (4) autoclaving. No detectable changes were found with gamma irradiation, but all other methods introduced some detectable change in the spectra. This suggests that common methods of sterilization alter the structure of the dentin, but gamma irradiation shows promise as a method which both is effective and introduces no detectable changes as measured by FTIR, UV/VIS/NIR, or permeability. PMID:7929992

White, J M; Goodis, H E; Marshall, S J; Marshall, G W

1994-09-01

37

Radiation Hard Fiber Optic Data Link for in situ gamma dot testing of TTL logic level I/O digital components and systems  

NASA Astrophysics Data System (ADS)

A radiation Hardened Fiber Optic Data Link which allows Automatic Test Equipment (ATE) to communicate with a device or system under test in a flash X-ray environment was designed, built, installed and tested. The data link uses TTL (Transistor to Transistor Logic) logic. The fiber optic data link has a Total Integrated Dose (TID) hardness greater than 250 krads and a gamma dose rate survivability greater than 1E12 rad (Si)/sec. Test data obtained by interfacing a Tektronix S-3295 with a DUT (which may be either a simple device or a full system) during gamma dose rate irradiation of 1E12 rad(Si)/sec is included. Except for the time delay the data link is transparent to the ATE. The link has a data rate greater than 60Mb/s NRZ (Non Return to Zero). AlGaAs 830nM LEDs and Si PIN diodes are used. The hardness of this link allows it to be used in a variety of applications.

Krinsky, Jeffrey A.; Majoch, Tim R.; Reynolds, Richard A.

38

30 CFR 57.5047 - Gamma radiation surveys.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Gamma radiation surveys. 57.5047 Section 57...METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter Radiation-Underground Only § 57.5047...

2013-07-01

39

GammaCam{trademark} radiation imaging system  

SciTech Connect

GammaCam{trademark}, a gamma-ray imaging system manufactured by AIL System, Inc., would benefit a site that needs to locate radiation sources. It is capable of producing a two-dimensional image of a radiation field superimposed on a black and white visual image. Because the system can be positioned outside the radiologically controlled area, the radiation exposure to personnel is significantly reduced and extensive shielding is not required. This report covers the following topics: technology description; performance; technology applicability and alternatives; cost; regulatory and policy issues; and lessons learned. The demonstration of GammaCam{trademark} in December 1996 was part of the Large-Scale Demonstration Project (LSDP) whose objective is to select and demonstrate potentially beneficial technologies at the Argonne National Laboratory-East (ANL) Chicago Pile-5 Research Reactor (CP-5). The purpose of the LSDP is to demonstrate that by using innovative and improved decontamination and decommissioning (D and D) technologies from various sources, significant benefits can be achieved when compared to baseline D and D technologies.

NONE

1998-02-01

40

[The effects of low doses of low-level gamma-radiation and phenozan injection on structural characteristics of mice spleen DNA].  

PubMed

It is well known that AKR mice with spontaneous leucosis are more sensitive to ionizing irradiation as compared to normal F1 (CBA x C57BL) mice. A study on changes of the structural characteristics of spleen DNA and level of protein p53 in the blood serum under the action of low-level gamma-irradiation in a dose of 1.2 cGy and injections of 10(-14) or 10(-4) mol/kg phenozan was performed. The changes in the structural characteristics of DNA (the adsorption on nitrocellulose filters and number of double-strand breaks) and p53 content were observed for each line of mice under gamma-irradiation and each phenozan concentration. Both factors showed long-time post-effects, and structural changes in AKR DNA were consistent with the life span of these mice. Phenozan in the above doses has abolished the induction of double-strand breaks in case of irradiation of F1 mice in a dose of 1.2 cGy and showed long-time post-irradiation effect. These facts suggest a radioprotection property of phenozan. PMID:17953428

Zhizhina, G P; Zavarykina, T M; Mil', E M; Burlakova, E B

41

Afterglow Radiation from Gamma Ray Bursts  

SciTech Connect

Gamma-ray bursts (GRB) are huge fluxes of gamma rays that appear randomly in the sky about once a day. It is now commonly accepted that GRBs are caused by a stellar object shooting off a powerful plasma jet along its rotation axis. After the initial outburst of gamma rays, a lower intensity radiation remains, called the afterglow. Using the data from a hydrodynamical numerical simulation that models the dynamics of the jet, we calculated the expected light curve of the afterglow radiation that would be observed on earth. We calculated the light curve and spectrum and compared them to the light curves and spectra predicted by two analytical models of the expansion of the jet (which are based on the Blandford and McKee solution of a relativistic isotropic expansion; see Sari's model [1] and Granot's model [2]). We found that the light curve did not decay as fast as predicted by Sari; the predictions by Granot were largely corroborated. Some results, however, did not match Granot's predictions, and more research is needed to explain these discrepancies.

Desmond, Hugh; /Leuven U. /SLAC

2006-08-28

42

Gamma radiation from the reaction ¹05Pd(p,n. gamma. )¹05Ag  

Microsoft Academic Search

The ..gamma.. radiation from the reaction ¹05Pd(p,n..gamma..)¹05Ag has been studied. To exclude impurity ..gamma.. rays we investigated also the ..gamma.. radiation from the reaction ¹06Pd(p,n..gamma..)¹06Ag. The ..gamma..-ray measurements were made with a Ge(Li) spectrometer with a sensitive volume of 30 cm³ and an energy resolution of 2.8 KeV for a ..gamma..-ray energy 1.3 MeV. As a result of the measurements

R. Mihu; Y. A. Aleksandrov; M. V. Aprelev; P. P. Zarubin

1977-01-01

43

Gamma radiation and gamma protection factors onboard ships during radioactive fallout  

Microsoft Academic Search

Methods of evaluating Gamma Ray Protection Factors (GRPF) for ships in various situations of radioactive fallout are discussed. These factors determine, in connection with a measured gamma radiation dose at a given detector point, the gamma radiation in different compartments of the ship. A computer program GASUFA was developed to calculate the GRPF. GASUFA performs calculations, considering energy, place, and

E. H. Brehm; T. Holst

1975-01-01

44

Fracture resistance of gamma radiation sterilized cortical bone allografts  

Microsoft Academic Search

Gamma radiation is widely used for sterilization of human cortical bone allografts. Previous studies have reported that cortical bone becomes brittle due to gamma radiation sterilization. This embrittlement raises concern about the performance of a radiation sterilized allograft in the presence of a stress concentration that might be surgically introduced or biologically induced. The purpose of this study was to

Ozan Akkus; Clare M. Rimnac

2001-01-01

45

Ultrarelativistic electrons and solar flare gamma-radiation  

NASA Astrophysics Data System (ADS)

Ten solar flares with gamma radiation in excess of 10 MeV were observed. Almost all took place within a heliolatitude greater than 60 deg, close to the solar limb, an indication of the essential anistropy of high-energy gamma radiation. This high-energy solar flare gamma radiation can be explained by the specific features of the bremsstrahlung of ultrarelativistic electrons trapped within the magnetic arc of the solar atmosphere, even if the acceleration of the electrons is anisotropic.

Semukhin, P. E.; Kovaltsov, G. A.

1985-08-01

46

Effect of gamma Radiation on Chlorophylls Content, Net Photosynthesis and Respiration of Chlorella Pyrenoidosa.  

National Technical Information Service (NTIS)

The effect of five doses of gamma radiation: 10, 100, 500, 1000 and 5000 Gy on chlorophylls content, net photosynthesis and respiration of Chlorella pyrenoidosa was studied. A decrease in chlorophylls levels is produced after irradiation at 500, 1000 and ...

C. Martin J. Fernandez

1983-01-01

47

RADIATION DETECTION AT BATTALION LEVEL  

Microsoft Academic Search

The purpose and scope of radiation detection is outlined, illustrating ; how and by whom such detection should be carried out at battalion level. judging ; by the results of radiation detection, the battalion commander decides how his ; troops will cross through the contamirated area and works out plans for ; eliminating the after-effects of radioactive contamination. When an

Manets

1960-01-01

48

Near ground gamma radiation associated with lightning  

NASA Astrophysics Data System (ADS)

Increases in the atmospheric gamma radiation of 22 to 82above normal background have been observed after the onset of lightning fifteen times since March 2001[1]. Gamma rays have been observed with up to four 12.9 cm3 NaI detectors and recently with a high resolution Ge detector positioned 6-21 m and 15 m above ground, respectively. The tail of the observed background subtracted gamma ray rates GRR were fitted with exponential decay curves yielding typical correlation coefficients of 0.95 to 0.99 and half-lives of 52.7 +/-4.81 min and 52.8+/-10.95 min, without and with precipitation, respectively. The GRR above 300 KeV from radon progeny due to precipitation were subtracted [2]. The 3x3 Ge detector with 2 KeV resolution positioned about 2 m from one of the NaI detectors observed increases in GRR minutes after the onset of lightning with a delayed 50 min exponential decay which was concurrently observed in the NaI detector. [1] M. B. Greenfield et al., Journal of Applied Physics 93 no. 3 (2003) pp 1839-1844. [2] M. B. Greenfield et al., Journal of Applied Physics 93 no. 9 (2003) pp 5733-5741.

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

2004-03-01

49

Gamma Radiation of Textile Waste-Water to Reduce Pollution.  

National Technical Information Service (NTIS)

A two-phase laboratory study of textile waste treatment by gamma radiation from a Cobalt-60 source was conducted. Laboratory prepared dye samples, starch sols, starch desize solutions, and PVA desize solutions were exposed to various dosages of radiation ...

1972-01-01

50

Gamma-ray laser based on storage level as the lasing level  

NASA Astrophysics Data System (ADS)

The possibility of using the isomeric level as the storage and lasing level in a gamma-ray laser is investigated. Experiments on Ag-109 and B-12 are used to illustrate the effect of homogeneous broadening on the coupling to the radiation field and the enhancement of relaxation under the influence of a 'resonant' magnetic field. An analysis is presented which shows the essential role of relaxation. The experimental results show the possibility of tuning relaxation times.

S'heeren, G.; van den Bergh, M.; Coussement, R.; Enzweiler, R. N.; Harris, R.; Wu, Y.; Boolchand, P.; Taylor, R. D.; Cyamukungu, M.; Lehmann, J.

51

Effect of gamma radiation on honey quality control  

Microsoft Academic Search

Honey is one of the most complex substances produced by bees, mainly from the nectar of flowers. Gamma radiation is a technique that can be used to decrease the number of microbiological problems associated with food and increase the shelf life of certain products. The objective of this study was to verify the effect of gamma radiation with source of

A. Bera; L. B. Almeida-Muradian; S. F. Sabato

2009-01-01

52

Radioimmunological study of regulation of insulin secrtion in the presence of acute radiation sickness. [Rats, gamma radiation  

Microsoft Academic Search

Rats were exposed to 750 R of gamma radiation and one group was given insulin subcutaneously during the period of hypercorticoidism and hyperglycemia. Rats were killed at intervals up to 10 days after irradiation and insulin was determined by radioimmunoassay. A table is presented to show effects of radiation on levels of corticosterone, glucose, and insulin at daily intervals. Results

Barkalaya

1977-01-01

53

Gamma radiation dose rate in indoor, outdoor and underground atmosphere around Tehri dam project, Uttarakhand, India  

Microsoft Academic Search

The natural pollution level due to gamma radiation was measured in about 22 residential houses around the Tehri Dam Project\\u000a in Uttarakhand state by using Environmental Radiation Dosimeter. Both urban and rural houses were selected for the measurements.\\u000a The recorded gamma dose rate in indoor atmosphere was found to vary from 25.1 ?R\\/h to 67 ?R\\/h with a mean value

M. S. Negi; Yogesh Prasad; Ganesh Prasad; G. S. Gusain; Manjari Badoni; R. C. Ramola

2009-01-01

54

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

Microsoft Academic Search

Deinococcus radiodurans is extremely resistant to ionizing radiation. How this bacterium can grow under chronic gamma-radiation (50 Gy\\/hour) or recover from acute doses greater than 10 kGy is unknown. We show that D. radiodurans accumulates very high intracellular manganese and low iron levels compared to radiation sensitive bacteria, and resistance exhibits a concentration-dependent response to Mn(II). Among the most radiation-resistant

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

2004-01-01

55

Effect of. gamma. radiation on sorption properties of polymethylphenylsiloxane films  

SciTech Connect

The effect of ..gamma.. radiation in the 0.01-1 MGy dose range on the capacity of polymethylphenylsiloxane films to sorb water vapors was studied. It was shown that the character of the change in the sorption capacity of the polymer films is a function of the dose of radiation. The results of measurements of the IR spectra were used in discussing the causes of the change in the sorption properties of the films on exposure to ..gamma.. radiation.

Eremina, N.S.; Minakova, T.S.; Komissarova, V.N.

1988-11-01

56

Prompt gamma radiation as a new tool to measure reactor power  

NASA Astrophysics Data System (ADS)

A new method, based on reactor prompt gamma radiation detection, for reactor power measurement is introduced and validated. To verify, the ex-core gamma radiation spectrum from the Iranian Heavy Water Zero Power Reactor (HWZPR) were measured by HPGe and NaI detectors each suitably positioned. The collective prompt gamma count rates for all or for a portion of each of 2?2? NaI detector spectra were obtained for seven power level readings from calibrated reactor power monitors. A good linear behavior was found between gamma count rate and reactor power. The method of calibrated prompt gamma reactor power determination is a stable and reliable tool, on-line, sensitive to sudden variation of power, working in pulse mode, increasing redundancy and diversity and so improving the reactor safety. The prompt gamma counting system can be adopted and installed in other nuclear reactors to measure power.

jalali, Majid; Abdi, Mohammad Reza; davati, Mojtaba Mostajabod

2013-10-01

57

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

NASA Astrophysics Data System (ADS)

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

Garcia, Tristan; Anton, Mathias; Sharpe, Peter

2012-01-01

58

Protective effects of melatonin and vitamin E in brain damage due to gamma radiation  

Microsoft Academic Search

Gamma radiation is known to cause serious damage in the brain, and many agents have been used for neuroprotection. In this study, lipid peroxidation levels and histopathological changes in brain tissues of whole-body irradiated rats with likely radiation injury were compared to those with melatonin and vitamin E protection. Forty rats in four equal groups were used. The control group

Fatih S. Erol; Cahide Topsakal; M. Faik Ozveren; Metin Kaplan; Nevin Ilhan; I. Hanifi Ozercan; Oguz G. Yildiz

2004-01-01

59

A Device for Search of Gamma-Radiation Intensive Sources at the Radiation Accident Condition  

SciTech Connect

The procedure designed for measuring angular distributions of gamma radiation and for search of gamma radiation intensive sources is described. It is based on application of the original multidetector device ShD-1, for measuring an angular distribution in a complete solid angle (4 pi). The calibration results and data on the angular distributions of intensity of gamma radiation at the roof of Chornobyl NPP ''Shelter'' are presented.

Batiy, Valeriy; Klyuchnykov, A; Kochnev, N; Rudko, Vladimir; shcherbin, vladimir; Yegorov, V; Schmieman, Eric A.

2005-08-08

60

Understanding radiation energy and its use in the preservation of seafoods. [X and gamma radiation  

Microsoft Academic Search

Some topics discussed are: the nature of radiation; radiation in the daily routine; penetration of radiation; radiation dosimetry; preservation of food; use of x and gamma radiation for preservation of seafood; and advantages of radiopreservation over heat-processing, freezing, and other methods of preserving seafoods. (HLW)

Ronsivalli

1976-01-01

61

Decontamination of black pepper and red pepper by gamma radiation  

NASA Astrophysics Data System (ADS)

The present study was conducted in order to evaluate the efficacy of gamma radiation to decontaminate imported black pepper and red pepper, which are commonly consumed in Algeria. Initial microbial load of the order of 107-108 microorganisms per gram of spices were found. It was established that a radiation dose of 6 kGy is sufficient to reduce the microbial contamination to below a level of 103 microorganisms per gram for both spices. Integrating irradiation with polyethylene packaging material afforded good protection against recontamination during 4 months of storage. The biological properties including sugars and essential oils were not affected by the irradiation treatment. Furthermore, at the dose of 8 kGy no sensory changes of spices were detected.

Oularbi, S.; Mansouri, B.

1996-09-01

62

Gamma radiation effects in Yb-doped optical fiber  

NASA Astrophysics Data System (ADS)

Determination of the radiation response of doped-fiber laser materials, systems and components to relevant ionizing radiation fluxes is central to the prediction of long-term fiber-based laser performance/survivability in adverse and/or space-based environments. It is well known that optical elements that are placed into orbit around the Earth experience harsh radiation environments that originate from trapped-particle belts, cosmic rays, and solar events. Of particular interest to optical materials is the continuous flux of gamma photons that the materials encounter. Such radiation exposure commonly leads to the formation of color centers in a broad range of optical materials. Such color center formation gives rise to changes in optical transmission, loss and luminescent band structure, and, thus, impacts long-term optical device performance. In this paper we will present the results of our investigation of gamma-radiation-induced photodarkening on the passive optical transmittance of a number of ytterbium- (Yb-) doped optical fibers. We will discuss the evolution of the optical response of the fiber across the 1.0 to 1.6 micron wavelength window with increasing gamma exposure. Results indicate that these fibers exhibit reasonable radiation resistance to gamma exposures typical of a 5-year, low-earth-orbit environment. Maximum transmittance losses of less than 10% were observed for total gamma exposures of 2-5 krad (Si). In this paper we will present the results of our investigation of gamma-radiation-induced photodarkening on the optical transmittance of a number of ytterbium- (Yb-) doped optical fibers. We will discuss the evolution of the optical response of the fiber across the 1.0 to 1.6 micron wavelength window with increasing gamma exposure. Results indicate that these fibers exhibit reasonable radiation resistance to gamma exposures typical of a 5-year, low-earth orbit environment. Maximum transmittance losses of less than 10% were observed for total gamma exposures of 2-5 krad (Si).

Fox, B. P.; Schneider, Z. V.; Simmons-Potter, K.; Thomes, W. J., Jr.; Meister, D. C.; Bambha, R. P.; Kliner, D. A. V.; Sderlund, M. J.

2007-02-01

63

Radiation Hard Fiber Optic Data Link for in situ gamma dot testing of TTL logic level I\\/O digital components and systems  

Microsoft Academic Search

A radiation Hardened Fiber Optic Data Link which allows Automatic Test Equipment (ATE) to communicate with a device or system under test in a flash X-ray environment was designed, built, installed and tested. The data link uses TTL (Transistor to Transistor Logic) logic. The fiber optic data link has a Total Integrated Dose (TID) hardness greater than 250 krads and

Jeffrey A. Krinsky; Tim R. Majoch; Richard A. Reynolds

1989-01-01

64

Modification in dielectric properties: Effect of gamma radiation  

NASA Astrophysics Data System (ADS)

The present paper reports the influence in dielectric properties caused by gamma radiation. The dielectric parameters have been measured for both unirradiated and gamma irradiated 5CB nematic liquid crystal with temperature variation in the frequency range 100 Hz to 10 MHz. Dielectric permittivity with variation in temperature has also been observed. The dielectric permittivity is found to increase for gamma irradiated sample as compared to the unirradiated sample with variation in temperature and frequency and well explained in this paper.

Dixit, Sudhaker; Tripathi, Prachi; Manohar, Rajiv; Arora, A. K.

2013-06-01

65

Inactivation of rabies diagnostic reagents by gamma radiation.  

PubMed Central

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

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

1980-01-01

66

Titanium-Water Thermosyphon Gamma Radiation Exposure and Results.  

National Technical Information Service (NTIS)

Titanium-water thermosyphons are being considered for use in heat rejection systems for fission power systems. Their proximity to the nuclear reactor will result in some gamma irradiation. Noncondensable gas formation from radiation-induced breakdown of w...

D. A. Goodenow D. A. Jaworske J. L. A. Sanzi

2012-01-01

67

Design, Construction and Calibration of a Polarimeter for gamma Radiation.  

National Technical Information Service (NTIS)

Information on different nuclear states can be obtained from the analysis of the angular distribution of the emitted gamma radiation. When the information is not sufficient to determine certain relevant parameters, or is ambiguous, a measurement of the li...

A. O. Macchiavelli G. V. Marti C. R. Gimeniz J. A. Laffranchi M. Behar

1980-01-01

68

Tables of Capacitor Discharge in Transient gamma Radiation Environments.  

National Technical Information Service (NTIS)

The tables in this report give the response of various types of capacitors to various transient gamma radiation environments. The tables were generated on the Burroughs B5500 digital computer at Stanford University. The parameters used to characterize the...

D. Landis

1965-01-01

69

Inactivation of rabies diagnostic reagents by gamma radiation  

SciTech Connect

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

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

1980-11-01

70

Impact of spectral smoothing on gamma radiation portal alarm probabilities  

Microsoft Academic Search

Gamma detector counts are included in radiation portal monitors (RPM) to screen for illicit nuclear material. Gamma counts are sometimes smoothed to reduce variance in the estimated underlying true mean count rate, which is the signal in our context. Smoothing reduces total error variance in the estimated signal if the bias that smoothing introduces is more than offset by the

T. Burr; M. Hamada; N. Hengartner

71

An investigation of gamma background radiation in Hamadan province, Iran.  

PubMed

The general population, everywhere in the world is exposed to a small dose of ionising radiation from natural sources. Stochastic effects such as cancer and genetic disorders are caused when living creatures are exposed to low doses. In Iran, it is measured in some cities, especially in high-background areas such as Ramsar, but so far there is no measurement in the Hamadan province. Hamadan is located in the west of Iran. Measurements were performed using a RDS-110 survey meter, CaSO(4):Dy thermoluminecense dosimetries (TLDs) and a Harshaw 4000 TLD reader. To estimate the dose rate outdoors, four stations along the main directions (north, south, west and east) and one in the town centre were selected. Mean annual X and gamma equivalent dose in Hamadan province are 1.120.22 and 1.660.07 mSv, which related to RDS-110 survey meter and TLDs measurements, respectively. The TLDs and RDS-110 results are representative of the external photon radiation doses for the selected monitoring locations and for those locations for the hours during which the measurements were taken, respectively. Maximum and minimum of external photon radiation doses are related to Hamadan and Kaboudar-Ahang towns, respectively. According to the results of the study, it seems that the annual X and gamma equivalent dose in Hamadan province exceeded the global mean external exposure amounts by the UNSCEAR, and further studies are needed to measure internal exposures to determine the total environmental radiation level in Hamadan province. PMID:22570508

Rostampour, Nima; Almasi, Tinoosh; Rostampour, Masoumeh; Mohammadi, Mohammad; Ghazikhanlou Sani, Karim; Khosravi, Hamid R; Pooya, S Mehdi Hosseini; Golzar, Bahman; Jabari Vesal, Naghi

2012-05-07

72

Effect of. gamma. radiation on sorption properties of polymethylphenylsiloxane films  

Microsoft Academic Search

The effect of ..gamma.. radiation in the 0.01-1 MGy dose range on the capacity of polymethylphenylsiloxane films to sorb water vapors was studied. It was shown that the character of the change in the sorption capacity of the polymer films is a function of the dose of radiation. The results of measurements of the IR spectra were used in discussing

N. S. Eremina; T. S. Minakova; V. N. Komissarova

1988-01-01

73

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

SciTech Connect

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

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

1998-05-01

74

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

NASA Astrophysics Data System (ADS)

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

Wang, Yan-Ping; Luo, Yin-Hong; Wang, Wei; Zhang, Ke-Ying; Guo, Hong-Xia; Guo, Xiao-Qiang; Wang, Yuan-Ming

2013-05-01

75

Effects of alpha, gamma, and alpha-Recoil Radiation on Borosilicate Glass Containing Savannah River Plant Defense High-Level Nuclear Waste.  

National Technical Information Service (NTIS)

At the Savannah River Plant, the reference process for the immobilization of defense high-level waste (DHLW) for geologic storage is vitrification into borosilicate glass. During geologic storage for 10 exp 6 y, the glass would be exposed to approx. 3 x 1...

N. E. Bibler

1981-01-01

76

INVESTIGATION OF EFFECTS OF RADIATION APPLICABLE AS GAMMA RADIATION DOSIMETERS. Period covered February 1957 through February 1958  

Microsoft Academic Search

This project was initiated to survey the field of radiation effects to ; determine which effects mmight be useful for high-level gamma dosimetry. ; Accordingly, the approach has been to survey the literature in broad areas and ; then to initiate experimental studies in those cases where additional information ; was required for evaluation of certain systems. It was not

J. F. Kircher; B. W. King; M. J. Oestmann; W. A. Hedden; J. H. Cahn; J. Moody; P. Schall; G. D. Calkins

1958-01-01

77

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

PubMed

The effect of gamma radiation on moisture content, total mold counts, Aspergillus counts, and aflatoxins of three hot pepper hybrids (Sky Red, Maha, and Wonder King) was investigated. Whole dried peppers packed in polyethylene bags were gamma irradiated at 0 (control), 2, 4, and 6 kGy and stored at 25C for 90 days. Gamma radiation proved to be effective in reducing total mold and Aspergillus counts in a dose-dependent relationship. Total mold counts in irradiated peppers immediately after treatments were significantly lowered compared with those in nonirradiated samples, achieving 90 and 99% reduction at 2- and 4-kGy doses, respectively. Aspergillus counts were significantly reduced, by 93 and 97%, immediately after irradiation at doses of 2 and 4 kGy, respectively. A radiation dose of 6 kGy completely eliminated the population of total molds and Aspergillus fungi. The evolution of total molds in control and irradiated samples indicated no further fungal proliferation during 3 months of storage at 25C. Aflatoxin levels were slightly affected by radiation doses of 2 and 4 kGy and showed a nonsignificant reduction of 6% at the highest radiation dose of 6 kGy. The distinct effectiveness of gamma radiation in molds and aflatoxins can be explained by the target theory of food irradiation, which states that the likelihood of a microorganism or a molecule being inactivated by gamma rays increases as its size increases. PMID:22856582

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

2012-08-01

78

Induction of p53 protein by gamma radiation in lymphocyte lines from breast cancer and ataxia telangiectasia patients  

Microsoft Academic Search

Exposure of human cells to gamma-radiation causes levels of the tumour-suppressor nuclear protein p53 to increase in temporal association with the decrease in replicative DNA synthesis. Cells from patients with the radiosensitive and cancer-prone disease ataxia telangiectasia (AT) exhibit radioresistant DNA synthesis and show a reduced or delayed gamma-radiation-induced increase in p53 protein levels. We have used Western immunoblotting with

GW Birrell; JR Ramsay

1995-01-01

79

Effect of gamma radiation on honey quality control  

NASA Astrophysics Data System (ADS)

Honey is one of the most complex substances produced by bees, mainly from the nectar of flowers. Gamma radiation is a technique that can be used to decrease the number of microbiological problems associated with food and increase the shelf life of certain products. The objective of this study was to verify the effect of gamma radiation with source of cobalto-60 (10 kGy) on some parameters used in honey quality control. Seven samples of pure honey were obtained from local markets in Sao Paulo, Brazil, in 2007. The methods used are in accordance with Brazilian Regulations. The physicochemical parameters analyzed were: moisture, HMF, free acidity, pH, sugars and ash. The results showed that gamma radiation, in the dose mentioned above, did not cause significant physicochemical alterations.

Bera, A.; Almeida-Muradian, L. B.; Sabato, S. F.

2009-07-01

80

Impact of spectral smoothing on gamma radiation portal alarm probabilities.  

PubMed

Gamma detector counts are included in radiation portal monitors (RPM) to screen for illicit nuclear material. Gamma counts are sometimes smoothed to reduce variance in the estimated underlying true mean count rate, which is the "signal" in our context. Smoothing reduces total error variance in the estimated signal if the bias that smoothing introduces is more than offset by the variance reduction. An empirical RPM study for vehicle screening applications is presented for unsmoothed and smoothed gamma counts in low-resolution plastic scintillator detectors and in medium-resolution NaI detectors. PMID:21612936

Burr, T; Hamada, M; Hengartner, N

2011-05-17

81

Features of the flux of gamma-radiation in the lower atmosphere during precipitation  

NASA Astrophysics Data System (ADS)

We are carrying out observations and studies of increases of gamma radiation intensity in a ground atmosphere layer during precipitations. Measurements have been carried out in two high-altitude points: Apatity (Murmansk) and Barentsburg (Spitsbergen). Scintillation detectors on the basis of NaI(Tl) crystals are used. Continuous radiation detection is made as the count rate in integral channels with threshold values >20 keV, >100 keV. There are more than 500 events of increase in gamma-ray background during precipitation. Average profiles of X-ray radiation increases in a ground level and the related with them increases of intensity of precipitations for stations in Apatity and Barentsburg have been built up. In Apatity the average increase profile in the gamma-ray flux and accompanying with profile of precipitations rate have been obtained. A time gap between peaks of precipitation and increase one is 30-40 minutes. A barometric coefficient of each component of radiation has been calculated. The barometric coefficient has a zero value on gamma-ray. The charged component of the secondary cosmic rays has a typical value ~0.18 %/mB. The lack of the barometric effect on gamma-ray indicates on the local origin of this radiation.

Germanenko, A. V.; Balabin, Yu V.; Gvozdevsky, B. B.; Vashenyuk, E. V.

2013-02-01

82

Radiation Levels Governing Nuclear Roce Ground Instrumentation  

Microsoft Academic Search

A rocket vehicle with a nuclear propulsion system assumes the environment of the reactor: specifically, the high intensity neutron and gamma radiation fields. The rocket system considered here is a booster-type vehicle of approximately 1.25 million pounds. Reactor power requirements for the specified mission and the necessity of minimum shielding result in a neutron flux in excess of 6 ??

W. E. Ivie; W. E. Jr

1962-01-01

83

Nano-Sensitization under gamma rays and fast ion radiation  

NASA Astrophysics Data System (ADS)

The use of heavy compounds to enhance radiation induced damage is a promising approach to improve the therapeutic index of radiotherapy. In order to quantify and control the effects of these radiosensitizers, it is of fundamental interest to describe the elementary processes which take place at the molecular level. Using DNA as a probe, we present a comparison of the damage induced in the presence of platinum compounds exposed to different types of ionizing radiation. We present the results obtained with gamma rays (Linear Energy Transfer (LET) = 0.2 keV.?m-1), fast helium ions He2+ (LET = 2.3 keV.?m-1) and fast carbon ions C6+ (LET = 13 keV.?m-1 and LET = 110 keV.?m-1). The efficiency of two different sensitizers was measured: platinum based molecules (the chloroterpyridine platinum - PtTC) and platinum nanoparticles (PtNP). These experiments show that the two sensitizers are efficiently amplifying molecular damage under photon or ion irradiation. Experiments with a radical scavenger confirmed that these damages are mediated by free radicals for more than 90%. More interestingly, the induction of complex damage, the most lethal for the cells, is amplified by a factor of 1.5 on average if platinum (PtTC and PtNP) is present. As already known, the induction of complex damages increases also with the radiation LET. So, finally, the most significant enhancement of complex damage is observed when ion radiation is combined with platinum induced sensitization.

Porcel, E.; Li, S.; Usami, N.; Remita, H.; Furusawa, Y.; Kobayashi, K.; Le Sech, C.; Lacombe, S.

2012-07-01

84

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

SciTech Connect

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

Patel, U.D.; Govindarajan, P.; Dave, P.J. (M.S. Univ. of Baroda (India))

1989-02-01

85

ACUTE EFFECTS OF GAMMA RADIATION IN PRIMATES  

Microsoft Academic Search

One hundred seven Macaca mulatta monkeys were exposed in 16 groups to ; rapid delivery of Co⁶° gamma rays at doses of 400 to 40,000 r. Statistical ; evaluation of the survival time determination of the LD 50\\/30 dose, clinical ; observations for a 30-day postirradiation period, and immediate postmortem ; examinations were performed. These three approaches to the investigation

R. G. Jr. Allen; F. A. Brown; L. C. Logie; D. R. Rovner; S. G. Jr. Wilson; R. W. Zellmer

1959-01-01

86

Environmental gamma radiation and fallout measurements in Finland, 1986-87. Supplement 2 to annual report STUK-A-74.  

National Technical Information Service (NTIS)

Results from a survey of environmental gamma radiation levels in Finland after the Chernobyl accident 1986 are presented. The measurements were made in 1986-87 by means of sensitive Geiger-counters and a gamma-spectrometer placed in cars. The results show...

H. Arvela H. Lemmelae L. Blomqvist M. Markkanen

1989-01-01

87

Effects of gamma Radiation on Peanut Plants.  

National Technical Information Service (NTIS)

The effects of radiation on the time of flowering, time of harvesting, quantity of pods, number of seeds, number of branches, plant height, number of chlorophyl, number of mutated plants, and morphological deformations in Arachis hypospea of Macan variety...

Kumala Dewi H. Muryono

1976-01-01

88

ACUTE EFFECTS OF GAMMA RADIATION IN PRIMATES  

Microsoft Academic Search

One hundred seven small primates were exposed in 16 groups to rapid ; delivery of Co⁶° gamma -rays at doses of 400 to 40,000 r. Statistical ; evaluation of survival times, determination of the LD\\/sub 50(30)\\/ dose, clinical ; observations for a 30day postirradiation period, and immediate postmortem ; examinations were performed. These three approaches to the investigntion of the

R. G. Allen; F. A. Brown; L. C. Logie; D. R. Rovner; S. G. Jr. Wilson; R. W. Zellmer

1960-01-01

89

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

SciTech Connect

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

Parra, S.A.

1994-11-30

90

KINETICS OF HYDROGEN PEROXIDE DECOMPOSITION BY $gamma$ RADIATION  

Microsoft Academic Search

Kinetics of the HO decomposition reaction in a wide range ; of aqueous concentrations (2 to 92 mole% HO) under the action of ; gamma radiation were investigated, and comparisons were made of some kinetic ; regularities of thermal and photo-reactions in the same range of concentrations. ; (R.V.J.);

V. Ya. Chernykh; S. Ya. Pshezhetskii; G. S. Tyurikov

1957-01-01

91

GAMMA RADIATION TREATMENT OF WATERS FROM LIGNITE MINES  

EPA Science Inventory

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

92

Observation of D(1285) -> phi gamma Radiative Decay.  

National Technical Information Service (NTIS)

The D(1285) radiative decay has been observed, 19+- events of this type have been detected. The branching ratio BR(D(1285) -> phi gamma )=(23+-5+-10) keV have been determined. The conclusion has been made that, most probably, the E(1420) meson does not be...

S. I. Bityukov G. V. Borisov V. A. Dorofeev

1987-01-01

93

POLYMERIZATION OF VINYL CHLORIDE UNDER EFFECT OF $gamma$RADIATION  

Microsoft Academic Search

Experiments were conducted on the polymerization of technical vinyl ; chloride under the effect of gamma radiation at with an activity of 18,000 g-; equiv Ra was used as the source. Ths polymerization kinetics was shown to obey ; the general laws governing free radical polymerization. There is a considerable ; induction period, because the initial radicals react with inhibiting

L. D. Bubis; V. L. Karpov; Yu. M. Malinskii; D. M. Yanovskii

1962-01-01

94

THE RESISTANCE TO $gamma$ RADIATION OF THE WORKER BEE  

Microsoft Academic Search

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

G. Courtois; J. Lecomte

1959-01-01

95

Biological and electron microscopic changes in gamma radiated Cryptococcus neoformans  

Microsoft Academic Search

Samples ofCryptococcus neoformans were irradiated with various doses of gamma radiation. The relatively low doses, 15 104 rads, resulted in no obvious effect on the fine structure of the cells but did seriously prevent a large proportion of the organisms from reproducing on agar. When subjected to doses of 1 106 rads virtually all the organisms lost their

H. M. Dembitzer; I. Buza; F. Reiss

1972-01-01

96

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

SciTech Connect

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

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

2012-12-15

97

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

SciTech Connect

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

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

2006-04-19

98

Bioburden assessment and gamma radiation inactivation patterns in parchment documents  

NASA Astrophysics Data System (ADS)

Parchment documents are part of our cultural heritage and, as historical artifacts that they are, should be preserved. The aim of this study was to validate an appropriate methodology to characterize the bioburden of parchment documents, and to assess the growth and gamma radiation inactivation patterns of the microbiota present in that material. Another goal was to estimate the minimum gamma radiation dose (Dmin) to be applied for the decontamination of parchment as an alternative treatment to the current toxic chemical and non-chemical decontamination methods. Two bioburden assessment methodologies were evaluated: the Swab Method (SM) and the Destructive Method (DM). The recovery efficiency of each method was estimated by artificial contamination, using a Cladosporium cladosporioides spore suspension. The parchment samples' microbiota was typified using morphological methods and the fungal isolates were identified by ITS-DNA sequencing. The inactivation pattern was assessed using the DM after exposure to different gamma radiation doses, and using C. cladosporioides as reference. Based on the applied methodology, parchment samples presented bioburden values lower than 5103 CFU/cm2 for total microbiota, and lower than 10 CFU/cm2 for fungal propagules. The results suggest no evident inactivation trend for the natural parchment microbiota, especially regarding the fungal community. A minimum gamma radiation dose (Dmin) of 5 kGy is proposed for the decontamination treatment of parchment. Determining the minimal decontamination dose in parchment is essential for a correct application of gamma radiation as an alternative decontamination treatment for this type of documents avoiding the toxicity and the degradation promoted by the traditional chemical and non-chemical treatments.

Nunes, Ins; Mesquita, Nuno; Cabo Verde, Sandra; Carolino, Maria Manuela; Portugal, Antnio; Botelho, Maria Lusa

2013-07-01

99

Fracture resistance of gamma radiation sterilized cortical bone allografts.  

PubMed

Gamma radiation is widely used for sterilization of human cortical bone allografts. Previous studies have reported that cortical bone becomes brittle due to gamma radiation sterilization. This embrittlement raises concern about the performance of a radiation sterilized allograft in the presence of a stress concentration that might be surgically introduced or biologically induced. The purpose of this study was to investigate the effect of gamma radiation sterilization on the fracture resistance of human femoral cortical bone in the presence of a stress concentration. Fracture toughness tests of specimens sterilized at a dose of 27.5 kGy and control specimens were conducted transverse and longitudinal to the osteonal orientation of the bone tissue. The formation of damage was monitored with acoustic emission (AE) during testing and was histologically observed following testing. There was a significant decrease in fracture toughness due to irradiation in both crack growth directions. The work-to-fracture was also significantly reduced. It was observed that the ability of bone tissue to undergo damage in the form of microcracks and diffuse damage was significantly impaired due to radiation sterilization as evidenced by decreased AE activity and histological observations. The results of this study suggest that, for cortical bone irradiated at 27.5 kGy, it is easier to initiate and propagate a macrocrack from a stress concentration due to the inhibition of damage formation at and near the crack tip. PMID:11562143

Akkus, O; Rimnac, C M

2001-09-01

100

Effect of glucocorticoids and gamma radiation on epidermal Langerhans cells  

SciTech Connect

The effect of 750 rads of gamma radiation on the rate of return of epidermal Langerhans cells (LC) following suppressive doses of topical glucorticoids was studied in guinea pigs. Gamma radiation alone had no effect on the LC as assessed by staining for cell membrane ATPase activity and Ia antigen. It did, however, delay the expected return of Ia but not ATPase surface markers on the LC after perturbation with glucocorticoids. The delayed return of surface Ia antigen is possibly related to a radiation-induced defect in the production of a required lymphokine and/or in intracellular Ia transport. Although our data do not rule out a cytolytic effect of steroids on the LC, they do strongly suggest that, at least in part, glucocorticoids act on the LC by altering cell surface characteristics.

Belsito, D.V.; Baer, R.L.; Thorbecke, G.J.; Gigli, I.

1984-02-01

101

Sublethal effects in Atlantic salmon (Salmo salar) exposed to mixtures of copper, aluminium and gamma radiation.  

PubMed

The present study was designed to investigate the effects in presmolt of Atlantic salmon (Salmo salar) exposed to copper (Cu), aluminium (Al) and gamma radiation, individually or in combination. Fish were exposed for 48 h to metals added to lake water; 10, 40 and 80 ?g Cu/L, 250 ?g Al/L and a combination of 40 ?g Cu/L and 250 ?g Al/L. In addition, gamma radiation (4-70 mGy delivered over 48 h) was added as an additional exposure stressor. Selected endpoints were chosen to reveal different toxic mechanisms and included Cu and Al accumulation on gills, blood chemistry and haematological variables (plasma sodium and chloride, haematocrit, glucose), hepatic levels of reduced and oxidised glutathione (GSH and GSSG) and hepatic transcriptional response of glutathione peroxidase (GPx), gamma-glutamylcysteine synthetase (GCS), metallothionein (MT) and ubiquitin. Exposure to Cu alone resulted in gill accumulation of Cu, reduction of plasma ions and increased transcriptional response of GPx, MT and ubiquitin. Exposure to Al alone reduced plasma ion levels but did not affect any of the hepatic biomarkers except for ubiquitin. The combined metal exposure (Cu + Al) altered the GSH levels, however GPx and MT were not affected suggesting a different mode of detoxification in the combined exposure. Gamma radiation appeared to influence GSH and ubiquitin levels. The observed effects seemed to be both stressor and concentration dependent. PMID:22583837

Heier, Lene Srlie; Teien, Hans Christian; Oughton, Deborah; Tollefsen, Knut-Erik; Olsvik, Pl A; Rosseland, Bjrn Olav; Lind, Ole Christian; Farmen, Eivind; Skipperud, Lindis; Salbu, Brit

2012-05-13

102

THERMAL RADIATION FROM GAMMA-RAY BURST JETS  

SciTech Connect

In this study, the light curves and spectrum of the photospheric thermal radiation from ultrarelativistic gamma-ray burst (GRB) jets are calculated using two-dimensional relativistic hydrodynamic simulations of jets from a collapsar. As the jet advances, the density around the head of the jet decreases, and its Lorentz factor reaches as high as 200 at the photosphere and 400 inside the photosphere. For an on-axis observer, the photosphere appears concave due to the low density and high beaming factor of the jet. The luminosity varies because of the abrupt change in the position of the photosphere due to the internal structure of the jet. Comparing our results with GRB 090902B, the flux level of the thermal-like component is similar to our model, although the peak energy appears slightly higher (but still within a factor of two). From the comparison, we estimate that the bulk Lorentz factor of GRB 090902B is {Gamma} {approx} 2.4 x 10{sup 2}(r/10{sup 12} cm), where r is the radius of the photosphere. The spectrum for an on-axis observer is harder than that for an off-axis observer. There is a time lag of a few seconds for high energy bands in the light curve. This may be the reason for the delayed onset of GeV emission seen in GRB 080916C. The spectrum below the peak energy is a power law and the index is 2.3-2.6, which is softer than that of a single temperature Planck distribution but still harder than that of the typical value of the observed spectrum.

Mizuta, Akira [Theory Center, Institute of Particle and Nuclear Studies, KEK (High Energy Accelerator Research Organization), 1-1 Oho, Tsukuba 305-0801 (Japan); Nagataki, Shigehiro; Aoi, Junichi, E-mail: mizuta@post.kek.jp [Yukawa Institute for Theoretical Physics, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan)

2011-05-01

103

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

NASA Astrophysics Data System (ADS)

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

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

104

GRABGAM Analysis of Ultra-Low-Level HPGe Gamma Spectra  

SciTech Connect

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

Winn, W.G.

1999-07-28

105

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

Microsoft Academic Search

As a continuation of a series of the studies on the flame and ..gamma..-radiation resistant modification of ethylene-propylene-diene rubber (EPDM), condensed bromoacenaphthylene (con-BACN) as a newly developed flame retardant was synthesized and its effects on the radiation resistance of EPDM were investigated. The radiation resistance evaluated by measuring tensile properties of irradiated sheets of 2 mm thick was found improved

Y. Morita; M. Hagiwara; N. Kasai

1982-01-01

106

Quality assurance of environmental gamma radiation monitoring in Slovenia.  

PubMed

Environmental gamma radiation monitoring established in Slovenia consists of a network of multifunctional gamma monitors (MFMs) based on pairs of Geiger-Mller counters and a network of measuring sites with high-sensitive thermoluminiscence dosemeters. The measuring points are evenly spread across Slovenia, located at the meteorological stations and more densely on additional locations around the Krsko NPP. The MFM network has a 2-fold function with one sensor used for the purpose of early warning system in near surroundings of the NPP and the other, more sensitive, for natural radiation monitoring. The paper summarises activities to establish quality assurance of the environmental gamma radiation measurements in Slovenia, with a critical view of the results in comparison with the international standards and recommendations. While the results of linearity and energy dependence tests were satisfying, on-field intercomparison showed that the inherent signal of one of the monitors (MFM) has to be taken into account in the range of environmental background radiation. PMID:16410289

Stuhec, M; Zorko, B; Miti?, D; Miljani?, S; Ranogajec-Komor, M

2006-01-12

107

Development of a qualitative dose indicator for gamma radiation using lyophilized Deinococcus.  

PubMed

The feasibility of using Deinococcus showing strong resistance to both desiccation and ionizing radiation as a dose indicator of gamma radiation exposure was evaluated. Three Deinococcus strains having different levels of radiation resistance, Deinococcus radiodurans (DRD), Deinococcus radiopugnans (DRP), and the DRD pprI mutant (DRM), were selected to develop an appropriate dose indicator for a broad range of exposures. DRD, DRP, and DRM cultures with different numbers of cells [~10(7) to 10(3) colony forming units (CFU)/100 microliter] were lyophilized and subjected to various doses of gamma radiation to determine a critical dose that inhibited bacterial growth completely. Finally, a combination of DRD at ~10(7) and ~10(6) CFU, DRP at ~10(5) CFU, and DRM at ~10(4) CFU successfully indicated exposure to 5, 10, 20, and 30 kGy of gamma radiation, respectively. This study shows the possibility of developing a qualitative indicator of radiation exposure using Deinococcus. PMID:22814506

Lim, Sangyong; Song, Dusup; Joe, Minho; Kim, Dongho

2012-09-01

108

Decay Curves and Half-lives of Gamma-Emitting States from a Study of Prompt Fission Gamma Radiation  

Microsoft Academic Search

Measurements were made on the time distributions of the prompt gamma radiation emitted from fragments in the thermal-neutron induced fission of 235U. 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 fragments. In this way decay curves were

H. Albinsson

1971-01-01

109

Anomalous primary radiation from the Leksell Gamma Knife Unit  

SciTech Connect

The Leksell Gamma Knife Unit, Type U, utilizes 201 separate {sup 60}Co sources intersecting at a common focus for radiosurgical treatment of the brain. It has been generally understood that all primary unattenuated radiation beams are confined with the protective housing during all phases of Gamma Knife operations. The authors have found that when the unit`s shielding door is lowered for treatment, twelve primary beams exit the unit`s door opening. Furthermore, in the original Gamma Knife unit design, two of the twelve primary beams failed to be attenuated by either the unit base or the unit wings. This has implications for the design of structural shielding and the protection of personnel during emergency procedures. Engineering modifications to eliminate the problem are discussed. 1 ref., 2 figs.

Shearer, D.R. [Rhode Island Hospital, Providence, RI (United States); Roventine, W.A. [Radiation Physics Services, Harrisville, RI (United States); Coy, S.R. [Neural Science Center, Coral Gables, FL (United States)

1994-12-01

110

Gamma heating measurements in a mixed radiation field  

SciTech Connect

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

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

1990-09-01

111

The Gamma-ray galactic diffuse radiation and Cerenkov telescopes  

SciTech Connect

By using the PYTHIA version of the Lund Monte Carlo program, we study the photon yield of proton-proton collisions in the energy range between 10 GeV and 1 TeV. The resulting photon spectrum turns out to scale roughly with incident energy. Then, by folding the energy spectrum of cosmic-ray protons with the distribution of HI and CO, the Galactic diffuse emission of {gamma}-rays above 100 GeV is mapped. Prospects for observing that diffuse radiation with atmospheric Cerenkov telescopes are discussed. Present instruments are able to detect the {gamma}-ray glow of the Galactic center. The latter will be mapped by the next generation of telescopes if their energy threshold is decreased. However, a detailed survey of the Galactic ridge will be a real challenge, even in the long term. The MILAGRO project seems more appropriate. Finally, we investigate the {gamma}-ray emission from weakly interacting massive particles clustering at the Galactic center. It has been speculated that those species are a major component of the halo dark matter. We show that their {gamma}-ray signal is swamped in the Galactic diffuse radiation and cannot be observed at TeV energies. {copyright} {ital 1995 The American Astronomical Society.}

Chardonnet, P. [Theoretical Physics Group ENSLAPP, BP110, F-74941 Annecy-le-Vieux Cedex (France)]|[Universite de Savoie, BP1104, 73011 Chambery Cedex (France); Salati, P. [Theoretical Physics Group ENSLAPP, BP110, F-74941 Annecy-le-Vieux Cedex (France)]|[Universite de Savoie, BP1104, 73011 Chambery Cedex (France)]|[Institut Universitaire de France; Silk, J. [545 Campbell Hall, Astronomy Department, University of California at Berkeley, Berkeley, California 94720 (United States); Grenier, I. [Departement dAstrophysique, Centre dEtudes Nucleaires de Saclay, F-91191 Gif-sur-Yvette Cedex (France); Smoot, G. [Building 50, Room 205, Lawrence Berkeley Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States)

1995-12-01

112

Modeling the radiation doses from terrestrial gamma-ray flashes  

NASA Astrophysics Data System (ADS)

Terrestrial gamma-ray flashes (TGFs) are intense bursts of gamma-rays that originate from thunderclouds, from altitudes that commercial aircraft fly. Based upon the fluence of gamma-rays measured by the RHESSI spacecraft, Dwyer et al. [2010] inferred radiation doses to individuals inside aircraft in the 0.001 - 0.1 Sv range, depending upon the assumed size of the TGF source region. The largest doses occur when an aircraft is directly struck by the energetic electron beam that produces the TGF. The relativistic feedback discharge model is a self-consistent model that includes the generation of runaway electrons via the positron and x-ray feedback mechanisms and the electric field changes due to the resulting ionization and low-energy electron and ion currents. This model has successfully explained many properties of TGFs, including the gamma-ray intensities, durations, multi-pulsed structures as well as discharge currents and radio emissions. In this presentation we discuss new radiation dose calculations based upon the relativistic feedback discharge model and compare these calculations to previous work.

Dwyer, Joseph; Liu, Ningyu; Rassoul, Hamid

2013-04-01

113

Production of light photinos in radiative decays of the form (. pi. /sup 0/. -->. gamma-tildegamma-tilde. gamma. )  

SciTech Connect

The probability of creation of light photinos in the radiative decay of the neutral pion, (..pi../sup 0/..-->..gamma-tildegamma-tilde..gamma..), is determined. Experimental limits on the mass and mass splitting of scalar quarks are used to determine the upper limit for the branching ratio in this process. The result is BR(..pi../sup 0/..-->..gamma-tildegamma-tilde..gamma..)approx. <10/sup -16/.

Dobrolyubov, M.I.; Ignat'ev, A.Y.

1988-06-01

114

Corrosion of copper-based materials in gamma radiation  

Microsoft Academic Search

The corrosion behaviors of pure copper (CDA 101), 7% aluminum-copper bronze (CDA 613) and 30% nickel-copper (CDA 715) are being studied in a gamma radiation field of 1 x 10⁵ R\\/h. These studies are in support of the Nevada Nuclear Waste Storage Investigations (NNWSI) Project, by Lawrence Livermore National Laboratory (LLNL), of copper-based materials for possible use in container systems

Yunker

1986-01-01

115

Observations of gamma radiation from the galactic center region  

Microsoft Academic Search

High resolution measurements of gamma-radiation, greater than 15 MeV, emitted from the galactic center were made during balloon flights in 1971 and 1975. The prominent feature observed in 1971 is a 29 deg wide enhancement lying along and just below the galactic equator. It is primarily confined and has an energy spectrum which appears to be dominated by pi deg-decay

G. H. Share; R. L. Kinzer; J. Samimi; A. Jabbari-Azad

1977-01-01

116

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

NASA Astrophysics Data System (ADS)

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

Plaza-Rosado, Heriberto

1991-09-01

117

Influence of gamma radiation onto polymeric matrix with papain  

NASA Astrophysics Data System (ADS)

Papain is a proteolytic enzyme that has been widely used as debridement agent for scars and wound healing treatment. However, papain presents low stability, which limits its use to extemporaneous or short shelf-life formulations. The purpose of this study was to entrap papain into a polymeric matrix in order to obtain a drug delivery system that could be used as medical device. Since these systems must be sterile, gamma radiation is an interesting option and presents advantages in relation to conventional agents: no radioactive residues are formed; the product can be sterilized inside the final packaging and has an excellent reliability. The normative reference for the establishment of the sterilizing dose determines 25 kGy as the inactivation dose for viable microorganisms. A silicone dispersion was selected to prepare membranes containing 2% (w/w) papain. Irradiated and non-irradiated membranes were simultaneously assessed in order to verify whether gamma radiation interferes with the drug-releasing profile. Results showed that irradiation does not affect significantly papain release and its activity. Therefore papain shows radioresistance in the irradiation conditions applied. In conclusion, gamma radiation can be easily used as sterilizing agent without affecting the papain release profile and its activity onto the biocompatible device is studied.

Zulli, Gislaine; Lopes, Patrcia Santos; Velasco, Maria Valria Robles; Alcntara, Mara Tnia Silva; Rogero, Sizue Ota; Lugao, Ademar Benvolo; Mathor, Monica Beatriz

2010-03-01

118

Low-level gamma-ray spectrometry for environmental samples  

Microsoft Academic Search

Low-level gamma-ray spectrometry with large volume HPGe detectors has been widely used in analysis of environmental radionuclides.\\u000a The reasons are excellent energy resolution and high efficiency that permits selective and non-destructive analyses of several\\u000a radionuclides in composite samples. Although the most effective way of increasing the sensitivity of a gamma-ray spectrometer\\u000a is to increase counting efficiency and the amount of

P. P. Povinec

2008-01-01

119

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

PubMed

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

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

2008-07-01

120

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

PubMed

Abstract This study evaluated liver from C57BL/6 mice irradiated with low-dose/low-dose-rate (LDR) ?-rays (0.01 Gy, 0.03 cGy/h), with and without subsequent exposure to acute 2 Gy gamma or proton radiation. Analyses were performed on day 56 post-exposure. Expression patterns of apoptosis-related genes were strikingly different among irradiated groups compared with 0 Gy (p < 0.05). Two genes were affected in the Gamma group, whereas 10 were modified in the LDR + Gamma group. In Proton and LDR + Proton groups, there were six and 12 affected genes, respectively. Expression of genes in the Gamma (Traf3) and Proton (Bak1, Birc2, Birc3, Mcl1) groups was no longer different from 0 Gy control group when mice were pre-exposed to LDR ?-rays. When each combined regimen was compared with the corresponding group that received acute radiation alone, two genes in the LDR + Gamma group and 17 genes in the LDR + Proton group were modified; greatest effect was on Birc2 and Nol3 (> 5-fold up-regulated by LDR + Protons). Oxygen radical production in livers from the LDR + Proton group was higher in LDR, Gamma, and LDR + Gamma groups (p < 0.05 vs. 0 Gy), but there were no differences in phagocytosis of E. coli. Sections stained with hematoxylin and eosin (H&E) suggested more inflammation, with and without necrosis, in some irradiated groups. The data demonstrate that response to acute radiation is dependent on radiation quality and regimen and that some LDR ?-ray-induced modifications in liver response were still evident nearly 2 months after exposure. PMID:23869974

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

2013-08-14

121

Repression of PTEN phosphatase by Snail1 transcriptional factor during gamma radiation-induced apoptosis  

Microsoft Academic Search

The product of the Snail1 gene is a transcriptional repressor required for triggering the epithelial-to-mesenchymal transition. Furthermore, ectopic expression of Snail1 in epithelial cells promotes resistance to apoptosis. In this study, we demonstrate that this resistance to gamma radiation-induced apoptosis caused by Snail1 is associated with the inhibition of PTEN phosphatase. In MDCK cells, mRNA levels of the p53 target

Sandra Peiro; Nicolas Herranz; Patricia Villagrasa; Natalia Dave; Sentis B Montserrat; Stephen A. Murray; C. Franci; Thomas Gridley; Ismo Virtanen; de Herreros Garcia

2008-01-01

122

Induction of transpositions of MGE Dm412 by {gamma}-radiation in an isogenic line of Drosophila melanogaster  

SciTech Connect

In an isogenic line of Drosophila, transpositions of mobile genetic elements (MGE) Dm412 were induced by {gamma}-radiation at doses of 300, 800, and 1300 R. The rates of induced transpositions were (for each dose, respectively) 3.9 x 10{sup {minus}3}, 1.0 x 10{sup {minus}2}, and 1.87 x 10{sup {minus}2} events per occupied site per haploid genome of the isogenic line per generation. Thus, the transposition rate increased linearly with the radiation dose. The specific rate of {gamma}-radiation-induced transpositions was (1.3 {+-} 0.6) x 10{sup {minus}5} per occupied site per haploid genome of the isogenic line per Roentgen per generation. {gamma}-Radiation-induced hot transposition sites and haplotypes, very similar to those induced by heat shock, were found. It was suggested that the mechanism of induction by {gamma}-radiation involves the heat shock system. Thus, it is more similar to the mechanism of temperature induction than to the direct mutational effect of {gamma}-radiation. Estimates of induced transposition rates per genome for each dose were calculated as 1.1, 3.0, and 5.6 events, respectively, per genome per generation. This level probably corresponds to the subthreshold level of genomes near the {open_quotes}catastrophic border of transpositional losses.{close_quotes} 21 refs., 1 fig., 4 tabs.

Zabanov, S.A. [Institute of Cytology and Genetics, Novosibirsk (Russian Federation); Vasil`eva, L.A.; Ratner, V.A. [Institute of Cytology and Genetics, Novosibirsk (Russian Federation)]|[Novosibirsk State Univ. (Russian Federation)

1995-06-01

123

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

NASA Astrophysics Data System (ADS)

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

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

124

A practical method for measuring angular distribution of radiation from multiple gamma sources  

SciTech Connect

Radiation survey data are a necessary prerequisite for planning D and D activities at a nuclear facility. For an individual room with a small number of high level radiation sources whose locations are known a priori, the survey process, shielding calculations, and work planning process are straightforward. However, when the space is large and complex, or when an accident has left process equipment and the space in disarray, gathering survey data while minimizing dose to the surveyor may require specialized equipment and analytical methods. The Object Shelter (OS) that encloses the destroyed Unit 4 at the Chernobyl Nuclear Power Plant (ChNPP) contains many intensive radiation sources such as fuel containing material (solidified melted fuel, fragment spent fuel, and fragmented fresh fuel), destroyed/contaminated piping and mechanical equipment, and contaminated dust and debris from accident recovery. These high intensity radiation sources are scattered throughout the facility in unknown configurations, so it is essential to know the angular distribution of gamma radiation in order to plan work and to design shielding. As previously reported, a prototype tool for measuring angular distribution of gamma radiation was developed, constructed and tested at ChNPP OS. The prototype device, designated ShD-1, consisted primarily of a lead (Pb) sphere containing recessed thermoluminescent detectors (TLDs). ShD-1 was successfully used to collect radiation survey data for planning the largest construction project yet performed at ChNPP OS, the stabilization project. From this application we gained insight into some limitations of the prototype design and report here advancements in the design. The multidetector device for measurement of angular distributions of intensity of gamma - radiation is described. Results of tests of experimental model of device are presented and prospects of use of such device are shown. (authors)

Batiy, V.; Pravdivyj, O.; Stoyanov, O. [Institute for Safety Problems of Nuclear Power Plants, National Academy of Sciences of Ukraine (Ukraine); Kochnev, N.; Selukova, V. [National Science Center -Kharkiv Institute of Physics and Technology (Ukraine); Schmieman, E. [Battelle Memorial Institute (United States)

2007-07-01

125

Current Trends in Gamma Radiation Detection for Radiological Emergency Response  

SciTech Connect

Passive and active detection of gamma rays from shielded radioactive materials, including special nuclear materials, is an important task for any radiological emergency response organization. This article reports on the current trends and status of gamma radiation detection objectives and measurement techniques as applied to nonproliferation and radiological emergencies. In recent years, since the establishment of the Domestic Nuclear Detection Office by the Department of Homeland Security, a tremendous amount of progress has been made in detection materials (scintillators, semiconductors), imaging techniques (Compton imaging, use of active masking and hybrid imaging), data acquisition systems with digital signal processing, field programmable gate arrays and embedded isotopic analysis software (viz. gamma detector response and analysis software [GADRAS]1), fast template matching, and data fusion (merging radiological data with geo-referenced maps, digital imagery to provide better situational awareness). In this stride to progress, a significant amount of interdisciplinary research and development has taken placetechniques and spin-offs from medical science (such as x-ray radiography and tomography), materials engineering (systematic planned studies on scintillators to optimize several qualities of a good scintillator, nanoparticle applications, quantum dots, and photonic crystals, just to name a few). No trend analysis of radiation detection systems would be complete without mentioning the unprecedented strategic position taken by the National Nuclear Security Administration (NNSA) to deter, detect, and interdict illicit trafficking in nuclear and other radioactive materials across international borders and through the global maritime transportationthe so-called second line of defense.

Mukhopadhyay, S., Guss, P., Maurer, R.

2011-09-01

126

Super-Eddington radiation transfer in soft gamma repeaters  

NASA Astrophysics Data System (ADS)

Bursts from soft gamma repeaters (SGRs) have been shown to be super-Eddington by a factor of 1000 and have been persuasively associated with compact objects. Super-Eddington radiation transfer on the surface of a strongly magnetic (greater than or equal to 1013 G) neutron star is studied and related to the observational constraints on SGRs. In strong magnetic fields, Thompson scattering is suppressed in one polarization state, so super-Eddington fluxes can be radiated while the plasma remains in hydrostatic equilibrium. We discuss a model which offers a somewhat natural explanation for the observation that the energy spectra of bursts with varying intensity are similar. The radiation produced is found to be linearly polarized to one part in 1000 in a direction determined by the local magnetic field, and intensity variations between bursts are understood as a change in the radiating area on the source. The net polarization is inversely correlated with burst intensity. Further, it is shown that for radiation transfer calculations in limit of superstrong magnetic fields, it is sufficient to solve the radiation transfer for the low opacity state rather than the coupled equations for both. With this approximation, standard stellar atmosphere techniques are utilized to calculate the model energy spectrum.

Ulmer, Andrew

1994-12-01

127

Radiation Field in Air Due to Distributed Gamma-Ray Sources in the Ground.  

National Technical Information Service (NTIS)

A much more complete and detailed picture of the external environmental gamma-ray radiation field has been obtained through gamma-ray transport calculations of exposure rates, differential energy spectra, integral exposure rate spectra, and angular exposu...

H. Beck G. de Planque

1968-01-01

128

Thermal Radiation from Gamma-ray Burst Jets  

NASA Astrophysics Data System (ADS)

In this study, the light curves and spectrum of the photospheric thermal radiation from ultrarelativistic gamma-ray burst (GRB) jets are calculated using two-dimensional relativistic hydrodynamic simulations of jets from a collapsar. As the jet advances, the density around the head of the jet decreases, and its Lorentz factor reaches as high as 200 at the photosphere and 400 inside the photosphere. For an on-axis observer, the photosphere appears concave due to the low density and high beaming factor of the jet. The luminosity varies because of the abrupt change in the position of the photosphere due to the internal structure of the jet. Comparing our results with GRB 090902B, the flux level of the thermal-like component is similar to our model, although the peak energy appears slightly higher (but still within a factor of two). From the comparison, we estimate that the bulk Lorentz factor of GRB 090902B is ? ~ 2.4 102(r/1012 cm), where r is the radius of the photosphere. The spectrum for an on-axis observer is harder than that for an off-axis observer. There is a time lag of a few seconds for high energy bands in the light curve. This may be the reason for the delayed onset of GeV emission seen in GRB 080916C. The spectrum below the peak energy is a power law and the index is 2.3-2.6, which is softer than that of a single temperature Planck distribution but still harder than that of the typical value of the observed spectrum.

Mizuta, Akira; Nagataki, Shigehiro; Aoi, Junichi

2011-05-01

129

EFFECTS OF GAMMA RADIATION ON ELECTROCHEMICAL PROPERTIES OF IONIC LIQUIDS  

SciTech Connect

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

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

2009-04-21

130

Can low-level radiation cause cancer?  

Microsoft Academic Search

Health in a multicellular organism is maintained by homeostatic processes. Disruption of these homeostatic controls at the molecular, biochemical, cellular, and organ systems levels can be brought about by irreversible changes in the genetic material (mutagenesis), cell death (cytotoxicity), or reversible changes in the expression of genes at the transcriptional, translational, or posttranslational levels (epigenesis). While radiation is known to

Trosko

1995-01-01

131

Role of ruvAB genes in UV- and gamma-radiation and chemical mutagenesis in Escherichia coli.  

PubMed

Escherichia coli umuC122::Tn 5 was mutagenized with N-methyl-N'-nitro-N-nitrosoguanidine to isolate mutations that block the residual gamma-radiation mutagenesis observed in umuC strains. Two of these mutations were shown by transductional mapping and plasmid complementation to map in the ruvA and ruvB genes (i.e., ruvA200 and ruvB201). Whereas ruvA200 was complemented by ruvA+ plasmids, the only other known ruvA mutation, ruvA59::Tn10 required both the ruvA+ and ruvB+ genes to show complementation. The ruvA200, ruvB201, ruvA59::Tn10 and ruvB60::Tn10 mutations all reduced gamma-radiation-induced ochre reversion [argE3(Oc)----Arg+] to about 30% of the wild-type level, and they all reduced UV-radiation-induced ochre reversion to about 15% of the wild-type level. The ruvA200 and ruvB201 mutants also showed reduced gamma- and UV-radiation mutagenesis with two other assays [hisG4(Oc)----His+ and Rifs----Rifr]. Streptozotocin mutagenesis (Rifr) was reduced to about half of the wild-type level in ruv strains, but ethyl methanesulfonate mutagenesis was normal. While the umuC strain did not show the oxygen enhancement of gamma-radiation mutagenesis, the ruvA200 strain showed an oxygen effect that was similar to that shown by the wild-type strain. When the ruvA200 mutation was combined with the umuC mutation, gamma-radiation mutagenesis was further reduced to 5% of the wild-type level and cells showed a synergistic sensitization to UV- and gamma-radiation-induced killing. A mutational spectrum analysis indicates a general depression of both umuC-dependent and umuC-independent gamma-radiation mutagenesis in the ruvA strain, which is in contrast with the site-specific reduction in gamma-radiation mutagenesis that is observed in the umuC mutant. The reduced radiation mutagenesis in the ruvA strain could not be correlated with a reduction in transcription of the recA or umuC genes. PMID:2554134

Sargentini, N J; Smith, K C

1989-11-01

132

Natural Radiation from Soil using Gamma-Ray Spectrometry  

SciTech Connect

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

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

2009-06-03

133

Heavy ion radiative capture: 12C(12C,{gamma})  

SciTech Connect

The heavy ion radiative capture reaction 12C(12C,{gamma}) has been investigated around a beam energy of 16 MeV. The total cross-section has been measured with the Fragment Mass Analyser at Argonne National Laboratory and found to be somewhat larger than has previously been measured. A subsequent measurement with the Gammasphere array has shown that a considerable proportion of this extra cross-section relates to a highly non-statistical decay through high-lying states in 24Mg.

Jenkins, D.G.; Fulton, B.R.; Pearson, J. [Department of Physics, University of York, York, YO10 5DD (United Kingdom); Lister, C.J.; Carpenter, M.P.; Freeman, S.; Hammond, N.; Janssens, R.V.F.; Khoo, T.L.; Lauritsen, T.; Moore, E.F.; Wuosmaa, A.H. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Fallon, P.; Goergen, A.; Macchiavelli, A.O.; McMahan, M. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720 (United States); Freer, M. [School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom); Haas, F. [IReS, Centre National de la Recherche Scientifique, F-67037 Strasbourg Cedex 2 (France)

2004-02-27

134

Population doses from environmental gamma radiation in Iraq  

Microsoft Academic Search

The exposure rates due to external gamma radiation were measured in 11 Iraqi governerates. Measurements were performed with an Environmental Monitoring System (RSS-111) in open air 1 m above the ground. The average absorbed dose rate in each governerate was as follows (number x 10(-2) microGy h-1): Babylon (6.0), Kerbala (5.3), Al-Najaf (5.4), Al-Kadysia (6.5), Wasit (6.5), Diala (6.5), Al-Anbar

B. A. Marouf; A. S. Mohamad; J. S. Taha; I. K. al-Haddad

1992-01-01

135

Radiomodifying and anticlastogenic effect of Zingerone on Swiss albino mice exposed to whole body gamma radiation.  

PubMed

The radioprotective effect and antigenotoxic potential of phenolic alkanone, Zingerone (ZO) were investigated in Swiss albino mice exposed to gamma radiation. To study the optimum dose for radiation protection, mice were administered with ZO (10-100mg/kgb.wt.), once daily for five consecutive days. One hour after the last administration of ZO on the fifth day, animals were whole body exposed to 10 Gy gamma radiations. The radioprotective potential was assessed using animal survival at an optimal ZO dose of 20mg/kgb.wt., administered prior to 7-11 Gy. Further, the radioprotective potential of ZO was also analyzed by haemopoietic stem cell survival (CFU) assay, mouse bone marrow micronucleus test and histological observations of intestinal and bone marrow damage. Effect of ZO pretreatment on radiation-induced changes in glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT) and lipid peroxidation (LPx) levels was also analyzed. ZO treatment resulted increase in the LD(50/30) by 1.8 Gy (dose reduction factor = 1.2). The number of spleen colonies after whole body irradiation of mice (4.5 or 7.5 Gy) was increased when ZO was administered 1h prior to irradiation. The histological observations indicated a decline in the villus height and crypt number with an increase in goblet and dead cell population in the irradiated group, which was normalized by pretreatment with ZO. A significant (p < 0.001) reduction in micronucleated polychromatic, normochromatic erythrocytes, increased PCE/NCE ratio, increase in the GSH, GST, SOD, CAT and decreased LPx levels were observed in ZO pretreated group when compared to the irradiated animals. Our findings demonstrate the potential of ZO in mitigating radiation-induced mortality and cytogenetic damage, which may be attributed to inhibition radiation-induced decline in the endogenous antioxidant levels and scavenging of radiation-induced free radicals. PMID:19463966

Rao, B Nageshwar; Rao, B S Satish; Aithal, B Kiran; Kumar, M R Sunil

2009-05-20

136

Low-level single and coincidence gamma-ray spectrometry  

Microsoft Academic Search

Analyses of anthropogenic and natural gamma-ray emitters in the environment require high sensitive detector systems operating\\u000a in coincidence-anticoincidence modes. Thanks to an excellent energy resolution and a high efficiency, large volume HPGe detectors\\u000a have been widely used in low-level gamma-ray spectrometry. In the present paper we discuss the characteristics of single and\\u000a coincidence (HPGe-NaI(Tl)) arrangements suitable for analysis of environmental

I. Skora; M. Jekovsk; R. Janik; K. Hol; M. Chud; P. P. Povinec

2008-01-01

137

Level densities and {gamma}-strength functions in Sm isotopes  

SciTech Connect

The level density and radiative strength functions (RSF) for {sup 146,147}Sm have been extracted. As one approaches the closed N = 82 neutron shell we see that the structures in the level density become more pronounced due to shell effects. The experimental level densities can be used to explore thermodynamical properties of the nucleus within the microcanonical ensemble.

Siem, S.; Guttormsen, M.; Larsen, A. C.; Nyhus, H. T.; Rekstad, J.; Syed, N. U. H.; Oedegaard, S. W. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Chankova, R. [North Carolina State University, Raleigh, NC 27695 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Schiller, A. [Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701 (United States); Voinov, A. [Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701 (United States); Frank Laboratory of Neutron Physics, Joint Institute of Nuclear Research, 141980 Dubna, Moscow region (Russian Federation)

2008-05-12

138

An experimental search for gamma radiation associated with thunderstorm activity  

SciTech Connect

This experiment is a repeat of an earlier experiment, but with more sensitive apparatus and in a location with a higher incidence of thunderstorm activity. The earlier experiment was undertaken by Ashby and Whitehead to investigate the theory that ball lightning might be associated with the annihilation of small amounts of antimatter, and it yielded some very interesting but inconclusive results. In the course of about 12 months of data taking, four high rate bursts of gamma radiation were detected. These events lasted a few seconds and had many thousands of counts (16500, 5000, 3700, and [gt] 7700. Unfortunately, the association of these gamma ray bursts with thunderstorms or ball lightning was not clearly established, although one of the bursts did occur during a local thunderstorm in rough coincidence with a lightning bolt striking a flagpole about 100 yards from the gamma ray detection crystals. A pulse height spectrum taken for this burst (no spectrum was taken for the other three) exhibited a significant peak, well above background, the energy of which appeared to be compatible with the 511 keV positron annihilation line. While the peak could not be unambiguously attributed to positron annihilation, this certainly appeared to be the most likely source.

Fryberger, D.

1992-11-01

139

An experimental search for gamma radiation associated with thunderstorm activity  

SciTech Connect

This experiment is a repeat of an earlier experiment, but with more sensitive apparatus and in a location with a higher incidence of thunderstorm activity. The earlier experiment was undertaken by Ashby and Whitehead to investigate the theory that ball lightning might be associated with the annihilation of small amounts of antimatter, and it yielded some very interesting but inconclusive results. In the course of about 12 months of data taking, four high rate bursts of gamma radiation were detected. These events lasted a few seconds and had many thousands of counts (16500, 5000, 3700, and {gt} 7700. Unfortunately, the association of these gamma ray bursts with thunderstorms or ball lightning was not clearly established, although one of the bursts did occur during a local thunderstorm in rough coincidence with a lightning bolt striking a flagpole about 100 yards from the gamma ray detection crystals. A pulse height spectrum taken for this burst (no spectrum was taken for the other three) exhibited a significant peak, well above background, the energy of which appeared to be compatible with the 511 keV positron annihilation line. While the peak could not be unambiguously attributed to positron annihilation, this certainly appeared to be the most likely source.

Fryberger, D.

1992-11-01

140

Gamma radiation effects on commercial Mexican bread making wheat flour  

NASA Astrophysics Data System (ADS)

Gamma irradiation is considered to be an alternative method for food preservation to prevent food spoilage, insect infestation and capable of reducing the microbial load. In the present investigation, commercial Mexican bread making wheat flour was irradiated at 1.0 kGy using a 60C Gammabeam 651 PT irradiator facility. No changes were detected in moisture, protein and ashes in gamma irradiated samples as compared to those of non-irradiated samples. Slight radiation effects were observed in the alveogram values and farinograph properties; the falling number decreased 11%, the absorption as well as the mixing tolerance were practically unchanged by irradiation. An increase of 15% in the stability value and a 29% in the dough development time were observed. Also the deformation energy decreased 7% with no change at all in the tenacity/extensibility factor. Total aerobic, yeast and mold counts were reduced 96%, 25% and 75%; respectively by the irradiation process. The obtained results confirm that gamma irradiation is effective in reducing the microbial load in bread making wheat flour without a significant change in the physicochemical and baking properties.

Agndez-Arvizu, Z.; Fernndez-Ramrez, M. V.; Arce-Corrales, M. E.; Cruz-Zaragoza, E.; Melndrez, R.; Chernov, V.; Barboza-Flores, M.

2006-04-01

141

Gamma thermometer based reactor core liquid level detector  

SciTech Connect

A system is provided which employs a modified gamma thermometer for determining the liquid coolant level within a nuclear reactor core. The gamma thermometer which normally is employed to monitor local core heat generation rate (reactor power), is midified by thermocouple junctions and leads to obtain an unambiguous indication of the presence or absence of coolant liquid at the gamma thermometer location. A signal processor generates a signal based on the thermometer surface heat transfer coefficient by comparing the signals from the thermocouples at the thermometer location. The generated signal is a direct indication of loss of coolant due to the change in surface heat transfer when coolant liquid drops below the thermometer location. The loss of coolant indication is independent of reactor power at the thermometer location. Further, the same thermometer may still be used for the normal power monitoring function.

Burns, T.J.

1983-09-20

142

Effects of gamma radiation on chondrogenic development in vitro  

SciTech Connect

Gamma radiation (0.9-8.0 Gy) was used as a perturbing agent to study factors influencing in vitro chondrogenesis of embryonic chick limb bud cell culture. Chondrogenesis was measured using a number of criteria, including (1) cartilage nodule production, (2) spectrophotometric determination of the amount of bound Alcian blue dye, and (3) computer-assisted analysis of the spatial distribution (area) and density of Alcian blue present in individual micromass colonies. Gamma radiation inhibited both cell proliferation and chondrogenesis in a dose- and time-dependent fashion. Administration of benzamide caused a significant increase in cell proliferation at 0.9 and 2.7 Gy, and in chondrogenesis at all doses. Cartilage nodule production was affected during the first 2 days (prior to 48 h) of culture only, suggesting that chondrocytic commitment occurs during this period. Cultures irradiated at 48 and 72 h produced the same number of nodules as controls, but bound significantly less dye, presumably because of decreased cell numbers and/or cell synthesis products. Computer analysis of micromass colonies provided data similar to those collected spectrophotometrically, but displayed the advantages of (1) increased sensitivity to individual variations, (2) the ability to collect data sets without having to pool three or more colonies, and (3) long-term storage of raw images for later analysis.

Garrison, J.C.; Uyeki, E.M.

1988-11-01

143

Effect of Gamma radiation on microbial population of natural casings  

NASA Astrophysics Data System (ADS)

The high microbial load of fresh and dry natural casings increases the risk of meat product contamination with pathogenic microorganims, agents of foodborn diseases. The aim of this work is to evaluate the killing effect of gamma radiation on the resident microbial population of pork and beef casings, to improve their hygiene and safety. Portions of fresh pork (small intestine and colon) and dry beef casings were irradiated in a Cobalt 60 source with absorbed doses of 1, 2, 5 and 10 kGy. The D10 values of total aerobic microorganisms in the pork casings were 1.65 kGy for colon and 1.54 kGy for small intestine. The D10 value found in beef dry casings (small intestine) was 10.17 kGy. Radurization with 5 kGy was able to reduce, at least, 6 logs the coliform bacteria in pork casings. The killing effect over faecal Streptococci was 4 logs for pork fresh casings and 2 logs for beef dry casings. Gamma radiation with 5 kGy proved to be a convenient method to reduce substantially the microbial population of pork fresh casings. Otherwise, the microbial population of beef dry casings still resisted to 10 kGy.

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

1998-06-01

144

Background compensation for a radiation level monitor  

DOEpatents

Background compensation in a device such as a hand and foot monitor is provided by digital means using a scaler. With no radiation level test initiated, a scaler is down-counted from zero according to the background measured. With a radiation level test initiated, the scaler is up-counted from the previous down-count position according to the radiation emitted from the monitored object and an alarm is generated if, with the scaler having crossed zero in the positive going direction, a particular number is exceeded in a specific time period after initiation of the test. If the test is initiated while the scale is down-counting, the background count from the previous down- count stored in a memory is used as the initial starting point for the up-count.

Keefe, D.J.

1975-12-01

145

Protection by S-2-(3-aminopropylamino)ethylphosphorothioic acid against radiation-induced leg contractures in mice. [Gamma Radiation  

SciTech Connect

S-2-(3-Aminopropylamino)ethylphosphorothioic acid (WR-2721) was shown to provide marked protection against development of radiation-induced leg contractures in C3Hf/Kam mice whose legs were exposed to single doses of gamma-radiation. The radiation doses ranged from 3300 to 6200 rads delivered to the right hind thighs from two parallelly opposed 137Cs sources. WR-2721 was given i.p. 30 min before irradiation. The severity of radiation-induced leg contractures in untreated and WR-2721-treated mice was followed for 342 days after irradiation. The degree of leg contractures in both control and WR-2721-treated mice increased up to 100 days after radiation, when the change stabilized, remaining more or less at the same level to the end of the observation period. During this entire period, the severity of contractures was less in WR-2721-treated mice. The dose-modifying factor for the level of 5 mm reduction in leg extension was 1.5 at 182 days after irradiation. Since WR-2721 did not prevent the radiocurability of 8-mm fibrosarcomas growing in the same legs, these data imply that WR-2721 has a high potential for increasing therapeutic gain when combined with irradiation in the treatment of tumors of an appreciable size.

Hunter, N.; Milas, L.

1983-04-01

146

Vital parameters related low level laser radiation  

NASA Astrophysics Data System (ADS)

The first work hypotesis is that biosensors on the patient detecting heart, breath rate and skin parameters, modulate laser radiation to enhance the therapeutic outcome; in the second work hypotesis: biofeedback could be effective, when integrated in the low level laser energy release.

Palmieri, Beniamino; Capone, Stefania

2011-08-01

147

Closed-Form E1 Radiative Strength Functions for Gamma-Decay and Photoabsorption  

SciTech Connect

Photoabsorption cross sections and {gamma}-decay strength functions are calculated and compared with experimental data to test simple phenomenological models of E1 gamma-strength description in the middle-weight and heavy atomic nuclei. Radiative strength functions with energy asymmetric shape are recommended for overall estimation of averaged gamma-strengths. Systematics for giant dipole resonance (GDR) parameters are given.

Plujko, Vladimir A.; Kadenko, Igor M.; Kulich, Elizaveta V.; Gorbachenko, Oleksandr M. [Nuclear Physics Department, Taras Shevchenko National University, Pr. Acad. Glushkova, 2, bldg. 11, 03022 Kyiv (Ukraine)

2009-01-28

148

Gamma Radiation Effects on Time-Dependent Iodine Partitioning.  

NASA Astrophysics Data System (ADS)

A need for characterization of the iodine source -term used in safety calculations for hypothesized fission reactor core disruptive accidents has motivated this study in iodine volatility. Previous experimental studies have been directed at evaluating volatility of iodine at a single time shortly (1-12 h) after introduction into the aqueous -phase. This work has explored the very important variables of time in solution and gamma radiation dose rate for a range of iodine concentrations (10('-8) - 10('-5) gI/ml) and pH's (5, 9 and 11). All experiments were performed at (TURN)25(DEGREES)C, first in the absence of a significant radiation field and later with a gamma radiation dose rate ranging from .003 MRad/hr to .06 MRad/hr. Iodine was introduced either as molecular I(,2) or NaI with I-131 (8.04 day half -life) as a tracer. Conditions present during the course of the experiment governed iodine solution chemistry thus determining whether volatile forms (I(,2) and HOI) would predominate. Results of experiments with nonirradiated systems indicated very little volatility with NaI initiated studies. I(,2) initiated systems at pH 5 were the most volatile whereas pH 9 and 11 I(,2) systems showed decreasing volatility with time. This has been explained by analysis of iodine aqueous chemistry. Total iodine concentration dependence has also been addressed. A pronounced radiation-induced reduction in iodine volatility in pH 5 iodide solutions has been demonstrated as well as a dose rate dependence in the transient phase. This effect is more pronounced in higher concentration solutions. As with nonirradiated systems, irradiated alkaline solutions exhibit low volatility. Explanations for the behavior of irradiated systems based on iodine radiolytic chemistry are provided. A computer based model incorporating water radiolysis and iodine radiolytic chemical reactions has been formulated and tested. The model successfully predicts radiation induced volatility changes in pH 5 iodide systems. The experimentally observed dose rate dependence is also verified; however, insufficient knowledge of alkaline system iodine radiolytic interactions prevented success under those conditions.

Marshall, Paul Watson

149

INVESTIGATIONS OF MOLTEN METALS WITH THE AID OF GAMMA-RADIATIONS  

Microsoft Academic Search

Gamma radiation was employed to investigate some molten metals and ; binary metallic systems. By measuring the number of pulses per minute (n) the ; attenuation (absorbtion) of gamma radiations during passage through a layer of ; molten metal was determined. The following technically pure metals and alloys ; studied were: Mg, Al, Cu, Zn, Sn, Pb, Al-Zn, Al-Cu, Al-Sn,

Belyaev

1961-01-01

150

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

DOEpatents

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

Hondorp, H.L.

1981-07-06

151

In situ determination of radon concentration and total gamma radiation in Kastel Gomilica, Croatia  

NASA Astrophysics Data System (ADS)

To determine current radiation background of the environment at the Giricic location in Kastel Gomilica, Croatia, in situ measurement of radon concentration (222Rn and 220Rn) in an open atmosphere on a ground level and at the height of 1.5 m has been made as well as total gamma radiation at the height of 1 m in an energy range of 15 keV to 2 MeV. The researched location was divided in three specific parts: (i) regulated area with the bottom ash and flying ash in the basis (old depot), (ii) unregulated area with waste materials, including bottom ash and flying ash, in the basis (new depot), (iii) uncontaminated area with no waste materials deposited on. Average radon concentration on a ground level was 213 Bq/m3 for the old depot, 214 Bq/m3 for the new depot and 59 Bq/m3 for the uncontaminated area and at the height of 1.5 m 20 Bq/m3 for the old depot, 34 Bq/m3 for the new depot and 26 Bq/m3 for the uncontaminated area. Average total gamma radiation values in selected energy range were 109.92 cps (counts per second) for the old depot, 357.76 cps for the new depot and 65.97 cps for the uncontaminated area. For selected radionuclides (214Pb, 137Cs, 228Ac, 234mPa, 40K and 214Bi) average gamma radiation values at characteristic energies have been determined as well.

Lovrencic, Ivanka; Barisic, Delko; Orescanin, Visnja; Lulic, Stipe

2007-10-01

152

Gamma-ray spectroscopy of high-spin levels in 67Ga  

Microsoft Academic Search

Reactions 64Zn( alpha ,p gamma )67Ga and 53Cr(16O, pn gamma )67Ga populated the levels in 67Ga. Gamma-gamma coincidence experiments were carried out at Ealpha =13 and 15 MeV with the ( alpha ,p gamma ) reaction and E(16)O=42 MeV with the heavy-ion reaction. The Doppler-shift attenuation method was used with the ( alpha ,p gamma ) reaction to deduce mean

A. M. Al-Naser; A. H. Behbehani; L. L. Green; A. N. James; C. J. Lister; P. J. Nolan; N. Rammo; J. F. Sharpey-Schafer; L. Zybert; R. Zybert

1978-01-01

153

Implication and hazard of radiation level in the building materials  

NASA Astrophysics Data System (ADS)

The natural radioactivity due to radium, thorium, and potassium in building material samples contribute to the radiation dose received by human beings significantly. It is essential to evaluate the activity levels of these nuclides for the assessment of natural radiation dose. Activity concentrations of the gamma emitting primordial radionuclides 232Th, 226Ra, and 40K were measured using high resolution gamma spectrometry technique with high purity germanium (HPGe) detector in building materials: sand, brick, granite, cement and rock, collected from various areas of Gulbarga and Koppal districts. The standard ASTM procedure was followed for the sample preparation. The distribution of radionuclides and variation in activity concentration depend upon the rock formation and the geological properties of the region. The activity of the three radionuclides, 232Th, 226Ra, and 40K, were found to be in the range of 3.1-227.1, 1.6-111, and 23.2-1505 Bq/kg, respectively. The dose related radiological parameters were also calculated for all the samples and the observations show that the activity concentrations of the radionuclides are well within the UNSCEAR limits.

Kerur, Basavaraj R.; Rajeshwari, Tanakanti; Siddanna, Rajesh; Kumar, Anil S.

2013-03-01

154

Search for Charmonium States Decaying to J/\\psi\\gamma \\gamma $ Using Initial-State Radiation Events  

SciTech Connect

We study the processes e{sup +}e{sup -} {yields} (J/{psi}{gamma}{gamma}){gamma} and e{sup +}e{sup -} {yields} (J/{psi}{pi}{sup -}{pi}{sup +}){gamma} where the hard photon radiated from an initial e{sup +}e{sup -} collision with center-of-mass (CM) energy near 10.58 GeV is detected. In the final state J/{psi}{gamma}{gamma} we consider J/{psi}{pi}{sup 0}, J/{psi}{eta}, {chi}{sub c1}{gamma}, and {chi}c{sub 2}{gamma} candidates. The invariant mass of the hadronic final state defines the effective e{sup +}e{sup -} CM energy in each event, so these data can be compared with direct e{sup +}e{sup -} measurements. We report 90% CL upper limits for the integrated cross section times branching fractions of the J/{psi}{gamma}{gamma} channels in the Y (4260) mass region.

Aubert, B.; Barate, R.; Bona, M.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Tisserand, V.; Zghiche, A.; Grauges, E.; /Barcelona U., ECM; Palano, A.; /Bari U. /INFN, Bari; Chen, J.C.; Qi, N.D.; Rong, G.; Wang, P.; Zhu, Y.S.; /Beijing, Inst. High Energy Phys.; Eigen, G.; Ofte, I.; Stugu, B.; /Bergen U.; Abrams, G.S.; /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /Ferrara U. /INFN, Ferrara /Frascati /Genoa U. /INFN, Genoa /Harvard U. /Heidelberg U. /Imperial Coll., London /Iowa U. /Iowa State U. /Johns Hopkins U. /Karlsruhe U., EKP /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT, LNS /McGill U. /Milan U. /INFN, Milan /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /Naples U. /INFN, Naples /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /Padua U. /INFN, Padua /Pennsylvania U. /Perugia U. /INFN, Perugia /Pisa U. /INFN, Pisa /Prairie View A-M /Princeton U. /Rome U. /INFN, Rome /Rostock U. /Rutherford /DAPNIA, Saclay /South Carolina U. /SLAC /Stanford U., Phys. Dept. /SUNY, Stony Brook /Tennessee U. /Texas U. /Texas U., Dallas /Turin U. /INFN, Turin /Trieste U. /INFN, Trieste /Valencia U., IFIC /Victoria U. /Warwick U. /Wisconsin U., Madison /Yale U.

2006-11-30

155

Phoswich scintillator for proton and gamma radiation of high energy  

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

156

Phoswich scintillator for proton and gamma radiation of high energy  

SciTech Connect

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

Tengblad, O.; Borge, M. J. G.; Briz, J. A.; Carmona-Gallardo, M.; Cruz, C.; Gugliermina, V.; Nacher, E.; Perea, A.; Sanchez del Rio, J.; Nieves, M. Turrion [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Nilsson, T.; Johansson, H. T.; Bergstroem, J.; Blomberg, E.; Buelling, A.; Gallneby, E.; Hagdahl, J.; Jansson, L.; Jareteg, K.; Masgren, R. [Department of fundamental Physics, Chalmers Univ. of Technology, S-41296 Goeteborg (Sweden); and others

2011-11-30

157

Investigation of discrete {gamma} radiation in interactions of 14.9-MeV neutrons with natural silicon by a total {gamma}-radiation measurement technique  

SciTech Connect

The discrete {gamma} radiation in the interaction of 14.9-MeV neutrons and a natural silicon sample is investigated with a total {gamma}-radiation measurement (TGRM) technique. Fifty prompt {gamma} lines, one delayed {gamma} line, and seven final nuclei are identified. Forty-one possible transitions are designated. Differential production cross sections of 40 {gamma} lines at 40 deg., 55 deg., 90 deg., 125 deg., and 140 deg. are determined. Using relative differential production cross sections, accurate integral isotopic cross sections of the {sup 28}Si(n,p){sup 28}Al reaction are determined, and partial integral isotopic cross sections of the {sup 28}Si(n,n'){sup 28}Si, {sup 28}Si(n,{alpha}){sup 25}Mg, {sup 29}Si(n,n'){sup 29}Si, and {sup 30}Si(n,n'){sup 30}Si reaction channels are also estimated. The present results are in good agreement with some recent experimental and evaluated results.

Zhou Hongyu; Su Jun; Zhao Baokui; Dong Liming; Fan Guoying; Zhang Fengshou [Key Laboratory of Beam Technology and Material Modification of Ministry of Education, Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China); Deng Fuguo [Department of Physics, Beijing Normal University, Beijing 100875 (China); Zhao Qiang [School of Nuclear Science and Engineering, North China Electric Power University, Beijing 102206 (China)

2010-10-15

158

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

PubMed

The effect of gamma radiation from (60)Co source and 2MeV electron beam was studied on two fluoroquinolone antibiotics viz norfloxacin and gatifloxacin in the solid state. The changes in reflectance spectrum, yellowness index, vibrational characteristics, thermal behavior, UV spectrum, chemical potency (HPLC) and microbiological potency were investigated. ESR measurement gave the number of free radical species formed and their population. The nature of final radiolytic impurities was assessed by studying the HPLC impurity profile. Both norfloxacin and gatifloxacin were observed to be radiation resistant, and did not show significant changes in their physico-chemical properties. They could be radiation sterilized at a dose of 25kGy. PMID:20444612

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

2010-04-20

159

International comparisons of air kerma standards in 137Cs gamma radiation  

Microsoft Academic Search

Comparisons of the air kerma standards of six national laboratories, carried out in 137Cs gamma radiation, show an overall agreement of 0,8 % between the standards. This result is not quite as good as that of comparisons in 60Co gamma radiation, mainly because the evaluation of the ionization-chamber wall correction is less accurate for 137Cs radiation. However, this agreement is

A. Leitner; J. Witzani; M. Boutillon; P. Allisy-Roberts; F. Delaunay; E. Leroy; P. Lamperti; C. Strachotinsky; I. Csete

1997-01-01

160

Mediate gamma radiation effects on some packaged food items  

NASA Astrophysics Data System (ADS)

For most of prepackaged foods a 10 kGy radiation dose is considered the maximum dose needed; however, the commercially available and practically accepted packaging materials must be suitable for such application. This work describes the application of ionizing radiation on several packaged food items, using 5 dehydrated food items, 5 ready-to-eat meals and 5 ready-to-eat food items irradiated in a 60Co gamma source with a 3 kGy dose. The quality evaluation of the irradiated samples was performed 2 and 8 months after irradiation. Microbiological analysis (bacteria, fungus and yeast load) was performed. The sensory characteristics were established for appearance, aroma, texture and flavor attributes were also established. From these data, the acceptability of all irradiated items was obtained. All ready-to-eat food items assayed like manioc flour, some pts and blocks of raw brown sugar and most of ready-to-eat meals like sausages and chicken with legumes were considered acceptable for microbial and sensory characteristics. On the other hand, the dehydrated food items chosen for this study, such as dehydrated bacon potatoes or pea soups were not accepted by the sensory analysis. A careful dose choice and special irradiation conditions must be used in order to achieve sensory acceptability needed for the commercialization of specific irradiated food items.

Inamura, Patricia Y.; Uehara, Vanessa B.; Teixeira, Christian A. H. M.; del Mastro, Nelida L.

2012-08-01

161

Radiation effects on silver and zinc battery electrodes. I. Interim report, April-July 1965. [. gamma. radiation  

Microsoft Academic Search

During the initial characterization of silver-zinc cell electrodes, and the study of effects of gamma radiation on them, excessive growth of dendrites from the zinc electrode occurred. Therefore, cadmium electrodes were substituted for zinc in this phase of the work. A silver electrode which had a capacity of 0.8 Ah lost 54 mg of material after a gamma dosage of

G. R. Argue; H. L. Recht; W. A. McCollum

1965-01-01

162

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

SciTech Connect

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

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

1987-05-01

163

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

Microsoft Academic Search

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

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

1991-01-01

164

Antistress effect of low-level radiation  

SciTech Connect

One of the well-known examples of radiation hormesis is the phenomenon called the adaptive response. Irradiation with low doses induces resistance against the detrimental effects of higher radiation dose applied after the low dose. The adaptive response can be well explained in terms of {open_quotes}stress responses{close_quotes} made by the cell or the organism. Various physical and chemical agents, when brought into contact with mammalian cells at low levels or doses, can induce a wide variety of specific biochemical and physiological changes. The authors have an example of cytogenic adaptive response of cultured fish cells to low doses of X rays. The micronucleus, an expression of the chromosome damage, induced by higher dose X-ray irradiation could be significantly reduced by the lower dose X rays applied prior to high-dose irradiation.

Yamada, Takeshi; Miyachi, Yukihisa [Toho Univ. School of Medicine, Tokyo (Japan); Ohyama, Harumi

1996-12-31

165

Airborne gamma-radiation survey of the Jabel Ishmas Quadrangle, Kingdom of Saudi Arabia  

USGS Publications Warehouse

An airborne gamma-radiation survey system, which includes digital recording and automatic data processing procedures developed by the U. S. Geological Survey Saudi Arabian Project, is used to collect spectral gamma-radiation data as an aid to regional geologic mapping of pediment areas on the Arabian Shield. The areal extent of rock units can generally be distinguished by the intensity of their radiation pattern. Rocks of ultramafic composition have low radiation response, whereas more felsic rocks reflect higher radiation response. Interpretations based on radiometric data enable the geologist to gain some understanding about the geologic setting of an area before he begins field mapping.

Flanigan, Vincent J.

1975-01-01

166

Gamma-ray Burst Prompt Emission: Jitter Radiation in Stochastic Magnetic Field Revisited  

Microsoft Academic Search

We revisit the radiation mechanism of relativistic electrons in the stochastic magnetic field and apply it to the high-energy emissions of gamma-ray bursts (GRBs). We confirm that jitter radiation is a possible explanation for GRB prompt emission in the condition of a large electron deflection angle. In the turbulent scenario, the radiative spectral property of GRB prompt emission is decided

Jirong Mao; Jiancheng Wang

2011-01-01

167

Latitude measurements of cosmic radiation intensity in stratosphere and at sea level on marine antarctic expeditions  

NASA Astrophysics Data System (ADS)

The correlation coefficients (W9R,x, t) for the activity minimum 1975 to 1976 were determined on the basis of: stratospheric latitude measurement; measurement of the flux of soft charged radiation and gamma radiation at sea level as a function of cutoff rigidity Rc and determination of the latitude effect for the charged and gamma radiations; checking of the geomagnetic cutoff thresholds Rc, computed using the IGRF magnetic field model; clarification of the role of the radioactive background for determining the latitude effect for low-energy particles. The design of the instrument used in cosmic ray measurements at sea level the processing of measurement data are described the results of latitude measurements of ionizing and gamma radiations at sea level are presented, latitude stratospheric measurements at the solar activity minimum 1975 to 1976 are outlined. The sea-level latitude measurements gave the flux of charged cosmic radiation and the distribution of cosmic ray intensity as a function of Rc. Comparison of the measurements made in the Northern and Southern Hemispheres in the Atlantic reveals a systematic difference in the Rc values which requires introduction of a correction.

Svirzhevskiy, N. S.

1985-11-01

168

Search for Radiative Penguin Decays B+-->rho+gamma, B0-->rho0gamma, and B0-->omegagamma  

Microsoft Academic Search

A search for the decays B-->rho(770)gamma and B0-->omega(782)gamma is performed on a sample of 211106 Upsilon(4S)-->BB events collected by the BABAR detector at the SLAC PEP-II asymmetric-energy e+e- storage ring. No evidence for the decays is seen. We set the following limits on the individual branching fractions: B(B+-->rho+gamma)<1.810-6, B(B0-->rho0gamma)<0.410-6, and B(B0-->omegagamma)<1.010-6 at the 90% confidence level. We use the quark

B. Aubert; R. Barate; D. Boutigny; F. Couderc; J.-M. Gaillard; A. Hicheur; Y. Karyotakis; J. P. Lees; V. Tisserand; A. Zghiche; A. Palano; A. Pompili; J. C. Chen; N. D. Qi; G. Rong; P. Wang; Y. S. Zhu; G. Eigen; I. Ofte; B. Stugu; G. S. Abrams; A. W. Borgland; A. B. Breon; D. N. Brown; J. Button-Shafer; R. N. Cahn; E. Charles; C. T. Day; M. S. Gill; A. V. Gritsan; Y. Groysman; R. G. Jacobsen; R. W. Kadel; J. Kadyk; L. T. Kerth; Yu. G. Kolomensky; G. Kukartsev; G. Lynch; L. M. Mir; P. J. Oddone; T. J. Orimoto; M. Pripstein; N. A. Roe; M. T. Ronan; V. G. Shelkov; W. A. Wenzel; M. Barrett; K. E. Ford; T. J. Harrison; A. J. Hart; C. M. Hawkes; S. E. Morgan; A. T. Watson; M. Fritsch; K. Goetzen; T. Held; H. Koch; B. Lewandowski; M. Pelizaeus; M. Steinke; J. T. Boyd; N. Chevalier; W. N. Cottingham; M. P. Kelly; T. E. Latham; F. F. Wilson; T. Cuhadar-Donszelmann; C. Hearty; N. S. Knecht; T. S. Mattison; J. A. McKenna; D. Thiessen; A. Khan; P. Kyberd; L. Teodorescu; A. E. Blinov; V. E. Blinov; V. P. Druzhinin; V. B. Golubev; V. N. Ivanchenko; E. A. Kravchenko; A. P. Onuchin; S. I. Serednyakov; Yu. I. Skovpen; E. P. Solodov; A. N. Yushkov; D. Best; M. Bruinsma; M. Chao; I. Eschrich; D. Kirkby; A. J. Lankford; M. Mandelkern; R. K. Mommsen; W. Roethel; D. P. Stoker; C. Buchanan; B. L. Hartfiel; S. D. Foulkes; J. W. Gary; B. C. Shen; K. Wang; D. del Re; H. K. Hadavand; E. J. Hill; D. B. Macfarlane; H. P. Paar; Sh. Rahatlou; V. Sharma; J. W. Berryhill; C. Campagnari; B. Dahmes; O. Long; A. Lu; M. A. Mazur; J. D. Richman; W. Verkerke; T. W. Beck; A. M. Eisner; C. A. Heusch; J. Kroseberg; W. S. Lockman; G. Nesom; T. Schalk; B. A. Schumm; A. Seiden; P. Spradlin; D. C. Williams; M. G. Wilson; J. Albert; E. Chen; G. P. Dubois-Felsmann; A. Dvoretskii; D. G. Hitlin; I. Narsky; T. Piatenko; F. C. Porter; A. Ryd; A. Samuel; S. Yang; S. Jayatilleke; G. Mancinelli; B. T. Meadows; M. D. Sokoloff; T. Abe; F. Blanc; P. Bloom; S. Chen; W. T. Ford; U. Nauenberg; A. Olivas; P. Rankin; J. G. Smith; J. Zhang; L. Zhang; A. Chen; J. L. Harton; A. Soffer; W. H. Toki; R. J. Wilson; Q. L. Zeng; D. Altenburg; T. Brandt; J. Brose; M. Dickopp; E. Feltresi; A. Hauke; H. M. Lacker; R. Mller-Pfefferkorn; R. Nogowski; S. Otto; A. Petzold; J. Schubert; K. R. Schubert; R. Schwierz; B. Spaan; J. E. Sundermann; D. Bernard; G. R. Bonneaud; F. Brochard; P. Grenier; S. Schrenk; Ch. Thiebaux; G. Vasileiadis; M. Verderi; D. J. Bard; P. J. Clark; D. Lavin; F. Muheim; S. Playfer; Y. Xie; M. Andreotti; V. Azzolini; D. Bettoni; C. Bozzi; R. Calabrese; G. Cibinetto; E. Luppi; M. Negrini; L. Piemontese; A. Sarti; E. Treadwell; F. Anulli; R. Baldini-Ferroli; A. Calcaterra; R. de Sangro; G. Finocchiaro; P. Patteri; I. M. Peruzzi; M. Piccolo; A. Zallo; A. Buzzo; R. Capra; R. Contri; G. Crosetti; M. Lo Vetere; M. Macri; M. R. Monge; S. Passaggio; C. Patrignani; E. Robutti; A. Santroni; S. Tosi; S. Bailey; G. Brandenburg; K. S. Chaisanguanthum; M. Morii; E. Won; R. S. Dubitzky; U. Langenegger; W. Bhimji; D. A. Bowerman; P. D. Dauncey; U. Egede; J. R. Gaillard; G. W. Morton; J. A. Nash; M. B. Nikolich; G. P. Taylor; M. J. Charles; G. J. Grenier; U. Mallik; J. Cochran; H. B. Crawley; J. Lamsa; W. T. Meyer; S. Prell; E. I. Rosenberg; A. E. Rubin; J. Yi; M. Biasini; R. Covarelli; M. Pioppi; M. Davier; X. Giroux; G. Grosdidier; A. Hcker; S. Laplace; F. Le Diberder; V. Lepeltier; A. M. Lutz; T. C. Petersen; S. Plaszczynski; M. H. Schune; L. Tantot; G. Wormser; C. H. Cheng; D. J. Lange; M. C. Simani; D. M. Wright; A. J. Bevan; C. A. Chavez; J. P. Coleman; I. J. Forster; J. R. Fry; E. Gabathuler; R. Gamet; D. E. Hutchcroft; R. J. Parry; D. J. Payne; R. J. Sloane; C. Touramanis; J. J. Back; C. M. Cormack; P. F. Harrison; F. Di Lodovico; G. B. Mohanty; C. L. Brown; G. Cowan; R. L. Flack; H. U. Flaecher; M. G. Green; P. D. Jackson; T. R. McMahon; S. Ricciardi; F. Salvatore; M. A. Winter; C. L. Davis; J. Allison; N. R. Barlow; R. J. Barlow; P. A. Hart; M. C. Hodgkinson; G. D. Lafferty; A. J. Lyon; J. C. Williams; A. Farbin; W. D. Hulsbergen; A. Jawahery; D. Kovalskyi; C. K. Lae; V. Lillard; D. A. Roberts; G. Blaylock; C. Dallapiccola; K. T. Flood; S. S. Hertzbach; R. Kofler; V. B. Koptchev; T. B. Moore; S. Saremi; H. Staengle; S. Willocq; R. Cowan; G. Sciolla; S. J. Sekula; F. Taylor; R. K. Yamamoto; D. J. Mangeol; P. M. Patel; S. H. Robertson; A. Lazzaro; V. Lombardo; F. Palombo; J. M. Bauer; L. Cremaldi; V. Eschenburg; R. Godang; R. Kroeger; J. Reidy; D. A. Sanders; D. J. Summers; H. W. Zhao; S. Brunet; D. Ct; P. Taras; H. Nicholson; N. Cavallo; F. Fabozzi; C. Gatto; L. Lista; D. Monorchio; P. Paolucci; D. Piccolo; C. Sciacca; M. Baak; H. Bulten; G. Raven; H. L. Snoek; L. Wilden; C. P. Jessop; J. M. Losecco; T. Allmendinger; K. K. Gan; K. Honscheid; D. Hufnagel; H. Kagan; R. Kass; T. Pulliam; A. M. Rahimi

2005-01-01

169

Gamma Ray Telescope Senses High-Energy Radiation  

NSDL National Science Digital Library

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

Wnet

2011-11-02

170

Gamma radiation effect on gas production in anion exchange resins  

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

171

Application of Jitter Radiation: Gamma-Ray Burst Prompt Polarization  

NASA Astrophysics Data System (ADS)

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

Mao, Jirong; Wang, Jiancheng

2013-10-01

172

Hydrogel membranes of PVAl/ clay by gamma radiation  

NASA Astrophysics Data System (ADS)

In the last decades several studies concerning the new methods for drug delivery system have been investigated. A new field known as "smart therapy" involves devices and drug delivery systems to detect, identify and treat the site affected by the disease, not interfering with the biological system. Cutaneous Leishmaniasis is an endemic disease that is characterized by the development of single or multiple localized lesions on exposed areas of skin and one coetaneous treatment could be a potential solution. The aim of this study was to obtain polymeric hydrogel matrices of poly(vinylalcohol)(PVAl) and chitosan with inorganic nanoparticles, which can release a drug according to the need of the treatment of injury caused by leishmania on the skin. The hydrogels matrices were obtained with PVAl/ chitosan and PVAl/ chitosan 0.5; 1.0 and 1.5% laponite RD clay, crosslinked by ionizing gamma radiation with dose of 25 kGy. The techniques used for characterization were swelling, gel fraction, Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TGA). After synthesis, the samples were immersed in distilled water and weighed in periods of time until 60 h for the swelling determination. The obtained results have indicated that the swelling of the membranes increases with clay concentration, in consequence of ionic groups present in the clay.

de Oliveira, M. J. A.; Parra, D. F.; Amato, V. S.; Lugo, A. B.

2013-03-01

173

Corrosion of copper-based materials in gamma radiation  

SciTech Connect

The corrosion behaviors of pure copper (CDA 101), 7% aluminum-copper bronze (CDA 613) and 30% nickel-copper (CDA 715) are being studied in a gamma radiation field of 1 x 10{sup 5} R/h. These studies are in support of the Nevada Nuclear Waste Storage Investigations (NNWSI) Project, by Lawrence Livermore National Laboratory (LLNL), of copper-based materials for possible use in container systems for the permanent geologic burial of nuclear waste. Weight loss, tear drop (stressed), and crevice specimens of the three materials were exposed to water vapor-air atmospheres at 95{sup 0}C and 150{sup 0}C and to liquid water at 95{sup 0}C for periods of one, three, and six months. Longer exposures are in progress. Measurements include: changes in the chemical composition of the gas and water, specimen weight changes, oxide film weights, evidence of microcracking and crevice corrosion, and chemical composition of the oxide films by Auger electron spectroscopy and x-ray diffraction. Interim results show considerable pit and under-film corrosion of alloys CDA 613 and CDA 715. Uniform corrosion rates range from 0.012 mil/yr (0.30 {mu}m/yr) to 0.22 mil/yr (5.6 {mu}m/yr), based on specimen weight losses during six- and seven-month exposures. The time dependencies will be determined as more data become available.

Yunker, W.H.

1986-06-01

174

Comparison of environmental radiation dosimetry and. gamma. -ray spectroscopy  

SciTech Connect

During the period 1975-1980, direct radiation dose rates were measured at 16 fixed locations in the vicinity of the Joseph M. Farley Nuclear Plant, Houston County, AL, by exposure of TLDs which were read quarterly. The average quarterly dose rates using LiF chips varied widely over the 6-yr period and were divided into 2 distinct population groups of 4 and 2 yr each, corresponding to the vendor labs supplying and reading the TLDs. The simultaneous exposure of CaSO/sub 4/:Dy TLDs for 2 yr gave a third set of values which fell between the 2 LiF groups. During the period December 1976-November 1980, simultaneous pressurized ion chamber (PIC) and in situ Ge(Li) ..gamma..-ray spectroscopy measurements were made at the same locations at approximately 6-month intervals. The average PIC dose rate values were in good agreement with the average 2-yr LiF TLD values. Also, good agreement resulted from converting the in situ radioactivity values to dose rates using conversion values previously published. The natural radioactivity and fallout /sup 137/Cs in the soil showed little variation for a specific site, but varied widely between some sites. With the event of rain at the end of a long dry period, there was a large increase in /sup 214/Pb activity detected. Short half-life manmade radionuclides were seen for a few months following several atmospheric nuclear tests by the People's Republic of China.

Jackson, W.M.; Spaulding, J.D.; Noakes, J.E.; Murphy, G.L.

1985-06-01

175

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

PubMed

For radiation monitoring at the site of nuclear power plant accidents such as Fukushima Daiichi, radiation detectors not only for gamma photons but also for alpha and beta particles are needed because some nuclear fission products emit beta particles and gamma photons and some nuclear fuels contain plutonium that emits alpha particles. We developed a radiation detector that can simultaneously monitor alpha and beta particles and gamma photons for radiation monitoring. The detector consists of three-layered scintillators optically coupled to each other and coupled to a photomultiplier tube. The first layer, which is made of a thin plastic scintillator (decay time: 2.4 ns), detects alpha particles. The second layer, which is made of a thin Gd(2)SiO(5) (GSO) scintillator with 1.5 mol.% Ce (decay time: 35 ns), detects beta particles. The third layer made of a thin GSO scintillator with 0.4 mol.% Ce (decay time: 70 ns) detects gamma photons. By using pulse shape discrimination, the count rates of these layers can be separated. With individual irradiation of alpha and beta particles and gamma photons, the count rate of the first layer represented the alpha particles, the second layer represented the beta particles, and the third layer represented the gamma photons. Even with simultaneous irradiation of the alpha and beta particles and the gamma photons, these three types of radiation can be individually monitored using correction for the gamma detection efficiency of the second and third layers. Our developed alpha, beta, and gamma detector is simple and will be useful for radiation monitoring, especially at nuclear power plant accident sites or other applications where the simultaneous measurements of alpha and beta particles and gamma photons are required. PMID:22128972

Yamamoto, Seiichi; Hatazawa, Jun

2011-11-01

176

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

NASA Astrophysics Data System (ADS)

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

Yamamoto, Seiichi; Hatazawa, Jun

2011-11-01

177

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

SciTech Connect

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

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

2011-11-15

178

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

SciTech Connect

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

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

2011-07-15

179

Determination of Canine Dose Conversion Factors in Mixed Neutron and Gamma Radiation Fields.  

National Technical Information Service (NTIS)

The primary objective of mixed-field neutron/gamma radiation dosimetry in canine irradiation experiments conducted at the Armed Forces Radiobiology Research Institute (AFRRI) is to determine the absorbed midline tissue dose (MLT) at the region of interest...

B. A. Torres R. C. Bhatt J. C. Myska B. K. Holland

1996-01-01

180

Effects of gamma Radiation on Lichens and Lichen-Forming Fungi and Algae.  

National Technical Information Service (NTIS)

Initial literature reports indicated that lichens were highly resistant to gamma radiation. A series of experiments were undertaken to determine why lichens were so resistant. In experiments with Cladonia mitis, C. sylvatica, C. verticillata, Parmelia sul...

F. H. Erbisch

1977-01-01

181

Effetti delle radiazioni (gamma) in film sottili di silicio amorfo idrogenato. (Effects of gamma radiations in hydrogenated amorphous silicon layers).  

National Technical Information Service (NTIS)

The behavior of hydrogenated amorphous silicon layers irradiated with a gamma ray source has been studied. The total dose was in the range 5 + 100k Gy. The dark current was used to investigate the time evolution. The recovery effect of radiation damage at...

S. Baccaro P. D'Atanasio G. Maiello M. Petti L. Schirone

1994-01-01

182

Standoff Performance of HPGe Detectors in Identification of Gamma-Ray Radiation Sources  

Microsoft Academic Search

The detection and identification of radiation sources at distances in the range of 15 meters or more is becoming increasingly important for illicit materials interdiction and the location of lost or orphan sources. In most locations, there is a considerable gamma-ray flux from natural background (NORM) and cosmic- induced nuclides. This gamma-ray flux varies with time, weather conditions, location, and

Ronald M. Keyser; Timothy R. Twomey; Sam Hitch

183

REVIEW ARTICLE: Semiconductor devices for gamma ray, X ray and nuclear radiation detection  

Microsoft Academic Search

The application of semiconductor devices to the detection and analysis of gamma ray, X-ray and nuclear radiations is outlined. After a brief discussion on semiconductor detector principles, including mode of operation, choice of material and energy resolution various types of semiconductor detector are described. The uses of semiconductor devices in the fields of nuclear particle counting and spectrometry, gamma spectrometry,

A. H. F. Muggleton

1972-01-01

184

Biological effect of gamma radiation on in vitro culture in rice.  

National Technical Information Service (NTIS)

Radiobiological effects of gamma radiation on different types of rice before or during in vitro culture, combined treatments of (sup 137)Cs (gamma)-rays and NaN(sub 3) on mature embryo culture, and irradiation on growth of calli derived from anther in ric...

Wang Cailian Xu Gang Shen Mei Chen Qiufang

1994-01-01

185

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

PubMed Central

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

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

2008-01-01

186

External gamma radiation and mortality from cardiovascular diseases in the German WISMUT uranium miners cohort study, 1946-2008.  

PubMed

It is currently unclear whether exposure of the heart and vascular system, at lifetime accumulated dose levels relevant to the general public (<500mGy), is associated with an increased risk of cardiovascular disease. Therefore, data from the German WISMUT cohort of uranium miners were investigated for evidence of a relationship between external gamma radiation and death from cardiovascular diseases. The cohort comprises 58,982 former employees of the Wismut company. There were 9,039 recorded deaths from cardiovascular diseases during the follow-up period from 1946 to 2008. Exposures to external gamma radiation were estimated using a detailed job-exposure matrix. The exposures were based on expert ratings for the period 1946-1954 and measurements thereafter. The excess relative risk (ERR) per unit of cumulative gamma dose was obtained with internal Poisson regression using a linear ERR model with baseline stratification by age and calendar year. The mean cumulative gamma dose was 47mSv for exposed miners (86%), with a maximum of 909mSv. No evidence for an increase in risk with increasing cumulative dose was found for mortality from all cardiovascular diseases (ERR/Sv=-0.13; 95% confidence interval (CI): -0.38; 0.12) and ischemic heart diseases (n=4,613; ERR/Sv=-0.03; 95% CI: -0.38, 0.32). However, a statistically insignificant increase (n=2,073; ERR/Sv=0.44; 95% CI: -0.16, 1.04) for mortality from cerebrovascular diseases was observed. Data on smoking, diabetes, and overweight are available for subgroups of the cohort, indicating no major correlation with cumulative gamma radiation. Confounding by these factors or other risk factors, however, cannot be excluded. In conclusion, the results provide weak evidence for an increased risk of death due to gamma radiation only for cerebrovascular diseases. PMID:23192731

Kreuzer, M; Dufey, F; Sogl, M; Schnelzer, M; Walsh, L

2012-11-29

187

Health effects of low-level radiation  

Microsoft Academic Search

This book presents papers on the uses and biological effects of radiation. Topics considered include low dose irradiation, radiation sources, radiation measurements, dosimetry, epidemiology, cancer risk, dose-response relationships, x-ray radiography, genetic consequences, radiation protection, legal aspects, plutonium release from the Rocky Flats Plant, and radioactive waste management.

Hendee

1984-01-01

188

Experimental Level Densities and {gamma}-Strength Functions in rare earth nuclei  

SciTech Connect

The level density and radiative strength function for {sup 146,147}Sm and {sup 163,164}Dy have been extracted from primary {gamma} spectra using the Oslo method. As one approaches the closed N = 82 neutron shell, the structures in the level density become more pronounced due to shell effects. The experimental level densities can be used to explore thermodynamic properties of the nucleus within the microcanonical ensemble. Pygmy resonances, which are based on the scissors mode and seen in deformed rare-earth nuclei, are not observed in near-spherical {sup 146,147}Sm, as expected. Pygmy resonances in {sup 163,164}Dy were studied after {sup 3}He-induced reactions and their width was found to be twice as wide as compared to results reported after neutron-capture reactions.

Siem, S.; Guttormsen, M.; Larsen, A. C.; Nyhus, H. T.; Ingebretsen, F.; Messelt, S.; Rekstad, J.; Syed, N. U. H. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Chankova, R. [North Carolina State University Raleigh, NC 27695 (United States); Triangle Universities Nuclear Laboratory Durham, NC 27708 (United States); Schiller, A. [Department of Physics and Astronomy Ohio University, Athens, Ohio 45701 (United States); Voinov, A. [Department of Physics and Astronomy Ohio University, Athens, Ohio 45701 (United States); Frank Laboratory of Neutron Physics, Joint Institute of Nuclear Research, 141980 Dubna, Moscow region (Russian Federation); Oedegaard, S. W. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Norwegian Defence Research Establishment, P.O. Box 25, N-2027 Kjeller (Norway)

2008-04-17

189

Radiation background in a LaBr3(Ce) gamma-ray scintillation detector.  

PubMed

Gamma-ray spectral analyses with a 5-cm 5-cm LaBr3(Ce) detector and a NaI(Tl) detector of the same size show that the LaBr3(Ce) has much better gamma-ray peak resolution and full-energy peak counting efficiency but worse detection sensitivity. The LaBr3(Ce) detector has relatively high intrinsic radiation background due to the naturally occurring La radioisotope in lanthanum. Although this La background is entirely below the energy of 1,500 keV, additional background is in the energy region between 1,500 keV and 2,750 keV. The manufacturer attributes this radiation to alpha particles emitted by the five short-lived progeny of an Ac impurity. Comparative values for peak resolution, full-energy peak counting efficiency, and detection sensitivity are reported for Am, Co, and Cs. Results of counting Cs sources at two activity levels demonstrate the impact of background on detection sensitivity. PMID:22048488

Rosson, Robert; Lahr, Jeffrey; Kahn, Bernd

2011-12-01

190

Geraniin down regulates gamma radiation-induced apoptosis by suppressing DNA damage.  

PubMed

Gamma ray irradiation triggers DNA damage and apoptosis of proliferating stem cells and peripheral immune cells, resulting in the destruction of intestinal crypts and lymphoid system. Geraniin is a natural compound extracts from an aquatic plant Nymphaea tetragona and possesses good antioxidant property. In this study, we demonstrate that geraniin rescues radiosensitive splenocytes and jejunal crypt cells from radiation-induced DNA damage and apoptosis. Isolated splenocytes from C57BL/6 mice treated with geraniin were protected against radiation injury of 2 Gy irradiation through the enhancement of the proliferation and attenuation of DNA damage. Also, geraniin inhibited apoptosis in radiosensitive splenocytes by reducing the expression level and immunoreactivity of proapoptotic p53 and Bax and increasing those of anti-apoptotic Bcl-2. In mice exposed to radiation, geraniin treatment protected splenocytes and intestinal crypt cells from radiation-induced cell death. Our results suggest that geraniin presents radioprotective effects by regulating DNA damage on splenocytes, exerting immunostimulatory capacities and inhibiting apoptosis of radiosensitive immune cells and jejunal crypt cells. Therefore, geraniin can be a radioprotective agent against ?-irradiation exposure. PMID:23541438

Bing, So Jin; Ha, Danbee; Kim, Min Ju; Park, Eunjin; Ahn, Ginnae; Kim, Dae Seung; Ko, Ryeo Kyeong; Park, Jae Woo; Lee, Nam Ho; Jee, Youngheun

2013-03-26

191

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

SciTech Connect

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

Tan, Ping; /Wisconsin U., Madison

2006-03-08

192

Search for radiative penguin decays B(+)-->rho(+)gamma, B(0)-->rho(0)gamma, and B(0)-->omegagamma.  

PubMed

A search for the decays B-->rho(770)gamma and B0-->omega(782)gamma is performed on a sample of 211 x 10(6) Upsilon(4S)-->BB events collected by the BABAR detector at the SLAC PEP-II asymmetric-energy e(+)e(-) storage ring. No evidence for the decays is seen. We set the following limits on the individual branching fractions: B(B+-->rho(+)gamma)<1.8 x 10(-6), B(B0-->rho(0)gamma)<0.4 x 10(-6), and B(B0-->omegagamma)<1.0 x 10(-6) at the 90% confidence level. We use the quark model to limit the combined branching fraction B [B-->(rho/omega)gamma]<1.2 x 10(-6), from which we determine a constraint on the ratio of Cabibbo-Kobayashi-Maskawa matrix elements |V(td)|/|V(ts)|. PMID:15698065

Aubert, B; Barate, R; Boutigny, D; Couderc, F; Gaillard, J-M; Hicheur, A; Karyotakis, Y; Lees, J P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Shelkov, V G; Wenzel, W A; Barrett, M; Ford, K E; Harrison, T J; Hart, A J; Hawkes, C M; Morgan, S E; Watson, A T; Fritsch, M; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Steinke, M; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; Wilson, F F; Cuhadar-Donszelmann, T; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Thiessen, D; Khan, A; Kyberd, P; Teodorescu, L; Blinov, A E; Blinov, V E; Druzhinin, V P; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bruinsma, M; Chao, M; Eschrich, I; Kirkby, D; Lankford, A J; Mandelkern, M; Mommsen, R K; Roethel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Foulkes, S D; Gary, J W; Shen, B C; Wang, K; Del Re, D; Hadavand, H K; Hill, E J; Macfarlane, D B; Paar, H P; Rahatlou, Sh; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Long, O; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Eisner, A M; Heusch, C A; Kroseberg, J; Lockman, W S; Nesom, G; Schalk, T; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S; Mancinelli, G; Meadows, B T; Sokoloff, M D; Abe, T; Blanc, F; Bloom, P; Chen, S; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Smith, J G; Zhang, J; Zhang, L; Chen, A; Harton, J L; Soffer, A; Toki, W H; Wilson, R J; Zeng, Q L; Altenburg, D; Brandt, T; Brose, J; Dickopp, M; Feltresi, E; Hauke, A; Lacker, H M; Mller-Pfefferkorn, R; Nogowski, R; Otto, S; Petzold, A; Schubert, J; Schubert, K R; Schwierz, R; Spaan, B; Sundermann, J E; Bernard, D; Bonneaud, G R; Brochard, F; Grenier, P; Schrenk, S; Thiebaux, Ch; Vasileiadis, G; Verderi, M; Bard, D J; Clark, P J; Lavin, D; Muheim, F; Playfer, S; Xie, Y; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Treadwell, E; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Patteri, P; Peruzzi, I M; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Crosetti, G; Vetere, M Lo; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Brandenburg, G; Chaisanguanthum, K S; Morii, M; Won, E; Dubitzky, R S; Langenegger, U; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Gaillard, J R; Morton, G W; Nash, J A; Nikolich, M B; Taylor, G P; Charles, M J; Grenier, G J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Yi, J; Biasini, M; Covarelli, R; Pioppi, M; Davier, M; Giroux, X; Grosdidier, G; Hcker, A; Laplace, S; Diberder, F Le; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Tantot, L; Wormser, G; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Chavez, C A; Coleman, J P; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; Hutchcroft, D E; Parry, R J; Payne, D J; Sloane, R J; Touramanis, C; Back, J J; Cormack, C M; Harrison, P F; Lodovico, F Di; Mohanty, G B; Brown, C L; Cowan, G; Flack, R L; Flaecher, H U; Green, M G; Jackson, P S; McMahon, T R; Ricciardi, S; Salvatore, F; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hart, P A; Hodgkinson, M C; Lafferty, G D; Lyon, A J; Williams, J C; Farbin, A; Hulsbergen, W D; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Flood, K T; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Staengle, H; Willocq, S; Cowan, R; Sciolla, G; Sekula, S J; Taylor, F; Yamamoto, R K; Mangeol, D J J; Patel, P M; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Ct, D; Taras, P; Nicholson, H; Cavallo, N; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M; Bulten, H; Raven, G; Snoek, H L; Wilden, L; Jessop, C P; Losecco, J M; Allmendinger, T; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pulliam, T; Rahimi, A M; Ter-Antonyan, R; Wong, Q K; Brau, J; Frey, R; Igonkina, O; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M

2005-01-03

193

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

SciTech Connect

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

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

1982-09-01

194

Health Aspects of Low-Level Radiation.  

National Technical Information Service (NTIS)

A brief description of natural background radiation is given. To understand the relationship between doses and effects the magnitude and distribution over time are stressed. The derivation of radiation protection standards and corresponding risks are disc...

A. M. Marko

1979-01-01

195

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

SciTech Connect

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

Pati, Jogesh C

2002-08-08

196

Improvement of bacteriological quality of frozen chicken by gamma radiation.  

National Technical Information Service (NTIS)

The possible use of gamma irradiation at doses of 1.6 to 4.0 kGy to improve bacteriological quality of frozen chicken was investigated. The effects of gamma irradiation on salmonella viability in frozen chicken and on sensory quality of frozen chicken wer...

K. Nouchpramool Y. Prachasitthisak S. Charoen S. Kanarat K. Kanignunta

1986-01-01

197

MORPHOLOGICAL CHANGES PRODUCED BY GAMMA RADIATION ON THE SPOROGONOUS CYCLE OF PLASMODIUM GALLINACEUM  

Microsoft Academic Search

It has been shown that gamma radiation administered to the sporogonous ; cycle of the malarial parasite Plasmodium gallinaceum inhibits its normal ; development within the host mosquito Aedes aegypti. The morphological changes ; which occur in the parasite in vivo, as a consequence of the exposure to ; radiation, have been described in some detail, and are demonstrated in

Levon A. Terzian

1961-01-01

198

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

SciTech Connect

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

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

2012-09-06

199

[Control of the main radiation parameters of a gamma teletherapy apparatus].  

PubMed

In radiotherapy a dosimetric method is used nowadays to control the magnitude of the radiation axis deviation from the isocenter (RL) of a gamma-beam therapeutic apparatus (gamma BTA). However, the use of the method requires special costly equipment. Besides, it is fairly laborious. The dosimetric method does not permit the measurement of the distance between the isocentre and the virtual source (DISvirt) A gamma-metric method of the RL and DISvirt control in the gamma BTA is described. It is based on the photogammametric treatment of a gamma-picture of a special test object. The method is marked by high accuracy and safety. In addition, the gamma BTA can also be used in operation of accelerating therapeutic units. PMID:2038255

Cherni?, A N; Va?nberg, M Sh

200

GAMMA RADIATION INTERACTS WITH MELANIN TO ALTER ITS OXIDATION-REDUCTION POTENTIAL AND RESULTS IN ELECTRIC CURRENT PRODUCTION  

SciTech Connect

The presence of melanin pigments in organisms is implicated in radioprotection and in some cases, enhanced growth in the presence of high levels of ionizing radiation. An understanding of this phenomenon will be useful in the design of radioprotective materials. However, the protective mechanism of microbial melanin in ionizing radiation fields has not yet been elucidated. Here we demonstrate through the electrochemical techniques of chronoamperometry, chronopotentiometry and cyclic voltammetry that microbial melanin is continuously oxidized in the presence of gamma radiation. Our findings establish that ionizing radiation interacts with melanin to alter its oxidation-reduction potential. Sustained oxidation resulted in electric current production and was most pronounced in the presence of a reductant, which extended the redox cycling capacity of melanin. This work is the first to establish that gamma radiation alters the oxidation-reduction behavior of melanin, resulting in electric current production. The significance of the work is that it provides the first step in understanding the initial interactions between melanin and ionizing radiation taking place and offers some insight for production of biomimetic radioprotective materials.

Turick, C.; Ekechukwu, A.; Milliken, C.

2011-05-17

201

Short term effects of gamma radiation on endothelial barrier function: uncoupling of PECAM-1.  

PubMed

A limiting factor in the treatment of cancer with radiotherapy is the damage to surrounding normal tissue, particularly the vasculature. Vessel pathologies are a major feature of the side effects of radiotherapy and little is known about early events that could initiate subsequent diseases. We tested the hypothesis that gamma radiation has early damaging effects on the human endothelial barrier. Two models were used; Human Brain Microcapillary Endothelial Cells (HBMEC), and Human Umbilical Vein Endothelial Cells (HUVEC). Endpoints included Trans-Endothelial Electrical Resistance (TEER), barrier permeability to 10 kDa and 70 kDa tracer molecules, and the localization of F-actin, and junction proteins and the Platelet Endothelial Cell Adhesion Molecule (PECAM-1). Radiation induced a rapid and transient decrease in TEER at 3 h, with effects also seen at the radiotherapy doses. This dip in resistance correlated to the transient loss of PECAM-1 in discrete areas where cells often detached from the monolayer leaving gaps. Redistribution of PECAM-1 was also seen in 3-D human tissue models. By 6 h, the remaining cells had migrated to reseal the barrier, coincident with TEER returning to control levels. Resealed monolayers contained fewer cells per unit area and their barrier function was weakened as evidenced by an increased permeability over 24 h. This is the first demonstration of a transient and rapid effect of gamma radiation on human endothelial barriers that involves cell detachment and the loss of PECAM-1. Considering the association of cell adhesion molecules with vasculopathies, such an effect has the potential to be clinically relevant to the longer-term effects of radiotherapy. PMID:23220351

Sharma, Preety; Templin, Thomas; Grabham, Peter

2012-12-05

202

What is the radiative process of the prompt phase of Gamma Ray Bursts?  

SciTech Connect

Despite the dramatic improvement of our knowledge of the phenomenology of Gamma Ray Bursts, we still do not know several fundamental aspects of their physics. One of the puzzles concerns the nature of the radiative process originating the prompt phase radiation. Although the synchrotron process qualifies itself as a natural candidate, it faces severe problems, and many efforts have been done looking for alternatives. These, however, suffer from other problems, and there is no general consensus yet on a specific radiation mechanism.

Ghisellini, G. [INAF-Osservatorio Astronomico di Brera, Via Bianchi 46 I-23807 Merate (Italy)

2010-07-15

203

Dual Purpose Gamma Thermometer for Use as a Reactor Power Level and Core Coolant Level Detector for Pressurized Water Reactors.  

National Technical Information Service (NTIS)

This citation summarizes a one-page announcement of technology available for utilization. A modified gamma thermometer has been studied for use in a pressurized water reactor as a local power level detector and core coolant level detector. Utilization of ...

1982-01-01

204

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

SciTech Connect

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

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

1981-07-01

205

Effects of gamma Radiation on Polymer Matrix Waste Forms.  

National Technical Information Service (NTIS)

A study has been made of the volume and weight changes, mechanical properties, and radiolytic gas production of polymer matrix waste forms during gamma irradiation in open containers. The work has been commissioned by the Department of the Environment as ...

D. I. Johnson S. G. Burnay D. C. Phillips

1986-01-01

206

Gamma radiation-induced proteome of Deinococcus radiodurans primarily targets DNA repair and oxidative stress alleviation.  

PubMed

The extraordinary radioresistance of Deinococcus radiodurans primarily originates from its efficient DNA repair ability. The kinetics of proteomic changes induced by a 6-kGy dose of gamma irradiation was mapped during the post-irradiation growth arrest phase by two-dimensional protein electrophoresis coupled with mass spectrometry. The results revealed that at least 37 proteins displayed either enhanced or de novo expression in the first 1 h of post-irradiation recovery. All of the radiation-responsive proteins were identified, and they belonged to the major functional categories of DNA repair, oxidative stress alleviation, and protein translation/folding. The dynamics of radiation-responsive protein levels throughout the growth arrest phase demonstrated (i) sequential up-regulation and processing of DNA repair proteins such as single-stranded DNA-binding protein (Ssb), DNA damage response protein A (DdrA), DNA damage response protein B (DdrB), pleiotropic protein promoting DNA repair (PprA), and recombinase A (RecA) substantiating stepwise genome restitution by different DNA repair pathways and (ii) concurrent early up-regulation of proteins involved in both DNA repair and oxidative stress alleviation. Among DNA repair proteins, Ssb was found to be the first and most abundant radiation-induced protein only to be followed by alternate Ssb, DdrB, indicating aggressive protection of single strand DNA fragments as the first line of defense by D. radiodurans, thereby preserving genetic information following radiation stress. The implications of both qualitative or quantitative and sequential or co-induction of radiation-responsive proteins for envisaged DNA repair mechanism in D. radiodurans are discussed. PMID:21989019

Basu, Bhakti; Apte, Shree Kumar

2011-10-11

207

METHOD AND APPARATUS FOR PRODUCING AND ANALYZING POLARIZED GAMMA RADIATION  

DOEpatents

A method of polarizing and resolving the plane of polarization of gamma rays is described. Polarization is produced by positioning a thin disc of ferromagnetic metal, cortaining /sup 57/Co, in a magnetic field. Resolution is accomplished by rotating a thin disc of iron enriched in /sup 57/Fe relative to a second magnetic field and noting the change of gamma absorption at each rotational position. (AEC)

Hamermesh, M.; Hanna, S.S.; Perlow, G.J.

1964-04-21

208

Health effects of low level radiation  

Microsoft Academic Search

Radiation is of many different types, almost all of which have been held to affect health in one way or another. However, it is the effects of ionizing radiation that have given rise to the most controversy and for which the need for assessment is most urgent. That there has been - and continues to be - much controversy about

R. Doll; S. Darby

1990-01-01

209

RADIATION EFFECTS AT THE MACROMOLECULAR LEVEL  

Microsoft Academic Search

Reaction mechanisms involved in the direct effects of radiation on ; proteins are discussed. Selected papers are cited to obtain an outline of the ; properties of those processes whereby energy absorbed in proteins or protein ; complexes might move from the initial point of absorption. to a critical site. ; In considering the changes induced by radiation which destroy

L. G. Augenstine; J. G. Carter; D. R. Nelson; H. P. Yockey

1960-01-01

210

High total dose gamma radiation assessment of commercially available SiGe heterojunction bipolar transistors  

NASA Astrophysics Data System (ADS)

Maintenance tasks of the future International Experimental Thermonuclear fusion Reactor (ITER) will require communication links between the remotely operated equipment in the reactor vessel and the control room, some of which need to be radiation tolerant up to MGy dose levels. As a key element of opto-electronic transceivers, we therefore assessed the DC behavior of a commercial-off-the-shelf (COTS) SiGe heterojunction bipolar transistor (HBT) under gamma radiation up to 15 MGy, with dose rates from 160 Gy/h to 27 kGy/h. Our in-situ measurements of the forward DC current gain (hfe) present a limited loss of about 30 % for a base current of 100 ?A, with a dependence on the biasing conditions and a thermally activated recovery. These first ever reported results up to MGy levels allow us to design circuit-hardened driving electronics for both photonic transmitters and receivers, enabling high bandwidth communications applied in a fusion reactor environment.

Van Uffelen, Marco; Geboers, Sam; Leroux, Paul; Berghmans, Francis

2005-09-01

211

A radiation transport model as a design tool for gamma densitometers  

Microsoft Academic Search

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

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

1999-01-01

212

Effect of gamma radiation on microbial safety and nutritional quality of kachri ( Cucumis callosus )  

Microsoft Academic Search

Fresh dried and old (612months) dried kachri (Cucumis callosus) were treated with 0, 2.5, 5 and 7kGy of gamma radiation in a cobalt 60 gamma cell (GC-1200). The irradiated samples of\\u000a kachri were stored at room temperature (28??2C). Total bacterial count and nutrient composition were evaluated immediately after\\u000a irradiation and at regular intervals of 1month during 3months of storage. Results

N. S. Nathawat; Priyanka Joshi; Brij Gopal Chhipa; Sachin Hajare; Madhu Goyal; M. P. Sahu; Govind Singh

213

Enhancement of natural background gamma-radiation dose around uranium microparticles in the human body  

Microsoft Academic Search

Ongoing controversy surrounds the adverse health effects of the use of depleted uranium (DU) munitions. The biological effects of gamma-radiation arise from the direct or indirect interaction between secondary electrons and the DNA of living cells. The probability of the absorption of X-rays and gamma-rays with energies below about 200 keV by particles of high atomic number is proportional to

John E. Pattison; Richard P. Hugtenburg; Stuart Green

2010-01-01

214

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

SciTech Connect

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

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

1985-11-01

215

Measurement of outdoor terrestrial gamma radiation in the Sultanate of Oman.  

PubMed

The terrestrial gamma radiation level was determined throughout the Sultanate of Oman over a 3-y period. The dose rate at 1 m above the ground was measured at 512 locations using a compensated Geiger-Miller detector. The activity concentration of soil/rock samples, collected from 112 locations, was determined by gamma spectrometry. Dose rates calculated from the activity concentrations compared well with the measured values corrected for the cosmic ray contribution. Some of the highest terrestrial dose rates, up to 110 nGy h(-1), were measured in shales (Wadi Bani Awf, Saih Hatat, and the Huqf) and exposed basement granites (Jebal Jalan and the Mirbat peninsula). Two small hot spots were found where the maximum dose rate was 1,024 nGy h(-1). The average dose rate in the main population area of the Batinah is 38.5 nGy h(-1) (0.29 mSv y(-1)) and Muscat 44.9 nGy h(-1) (0.34 mSv y(-1)). The mean population weighted dose rate is 39.8 nGy h(-1) (0.30 mSv y(-1)). Most of Oman's surface rock is limestone, which is low in concentrations of radionuclides from the uranium and thorium series. Hence, the average dose rate is well below the world average of 0.45 mSv y(-1). PMID:12046760

Goddard, C C

2002-06-01

216

X- and gamma-ray N+PP+ silicon detectors with high radiation resistance  

NASA Astrophysics Data System (ADS)

The paper describes some results concerning technology and behavior of x and gamma-ray N(superscript +)PP(superscript +) silicon detectors used in physics research, industrial and medical radiography and non-destructive testing. These detectors work at the room-temperature and can be used individually to detect x- and soft gamma-rays, or coupled with scintillators for higher incoming energies. Electrical characteristics of these photodiodes, their modification after exposure to radiation and results of spectroscopic x- and gamma-ray measurements are discussed. Devices manufactured under this technology proved to be stable after an exposure in high intensity gamma field with the dose range of 10 krad - 5 Mrad. Nuclear radiation resistance was studied by irradiation with (superscript 60)Co gamma source (1.17, 1.33 MeV) at dose rates of 59 krad/hour and 570 krad/hour. Results indicate that proposed structures enable the development of reliable silicon detectors to be used in high gamma-radiation environments encountered in a lot of applications.

Cimpoca, Valerica; Petris, Mariana; Ruscu, Radu; Breten, Madalina; Moraru, Rodica

1997-07-01

217

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

DOEpatents

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

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

2013-02-12

218

Gamma radiation induced degradation in PE-PP block copolymer  

SciTech Connect

In the present investigation, effect of gamma irradiation on the PP-PE block copolymer has been studied. The polymer has been subjected to gamma irradiation from 100 to 500 Mrad dosages. Characterization of the polymer using XRD and FTIR was done both before irradiation and after irradiation in each step. Effect of irradiation on the electrical properties of the material has also been studied. FTIR study shows that the sample loses C - C stretching mode of vibration but gains C=C stretching mode of vibration after irradiation. Present investigation clearly indicates that though the electrical conductivity increases in the material, it undergoes degradation and shows brittleness due to irradiation.

Ravi, H. R.; Sreepad, H. R.; Ahmed, Khaleel; Govindaiah, T. N. [P.G. Department of Physics, Government College (Autonomous), Mandya - 571401, Karnataka State (India)

2012-06-05

219

Calibration of the maize yg2 assay using gamma radiation and ethylmethanesulfonate  

SciTech Connect

A standard protocol for the yellow-green-2 (yg2) forward mutation assay in Zea mays is proposed. A detailed calibration of the assay using /sup 137/Cs gamma rays and ethylmethanesulfonate (EMS) was conducted. Gamma ray-induced mutant sectors in leaves 4 and 5 exhibited one-hit kinetics. The radiation doses ranged from 25 to 500 rads. The mean induced mutation rate per rad of gamma radiation was 4.54 X 10/sup -6/. The induction of forward mutation by EMS also exhibited one-hit kinetics in the concentration range 0.25-20 mM. The mean induced mutation rate per mM EMS was 1.79 X 10/sup -4/, and the mean induced mutation rate per ..mu..mol of EMS per kernel was 1.52 X 10/sup -4/. Using the induced mutation rates for gamma radiation and EMS, the rad equivalent was calculated. One rad of gamma radiation is equivalent to the exposure of a 2.53 X 10/sup -5/ M EMS solution or to 2.99 X 10/sup -8/ mol of EMS per kernel.

Plewa, M.J.; Dowd, P.A.; Wagner, E.D.

1984-01-01

220

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

221

Patient doses in {gamma}-intracoronary radiotherapy: The Radiation Burden Assessment Study  

SciTech Connect

Purpose: To determine accurately the radiation burden of both patients and staff from intracoronary radiotherapy (IRT) with {sup 192}Ir and to investigate the importance of IRT in the patient dose compared with interventional X-rays. Methods and materials: The Radiation Burden Assessment Study (RABAS) population consisted of 9 patients undergoing {gamma}-IRT after percutaneous transluminal coronary angioplasty and 14 patients undergoing percutaneous transluminal coronary angioplasty only as the control group. For each patient, the dose to the organs and tissues from the internal and external exposure was determined in detail by Monte Carlo N-particle simulations. Patient skin dose measurements with thermoluminescence dosimeters served as verification. Staff dosimetry was performed with electronic dosimeters, thermoluminescence dosimeters, and double film badge dosimetry. Results: With respect to the patient dose from IRT, the critical organs are the thymus (58 mGy), lungs (31 mGy), and esophagus (27 mGy). The mean effective dose from IRT was 8 mSv. The effective dose values from interventional X-rays showed a broad range (2-28 mSv), with mean values of 8 mSv for the IRT patients and 13 mSv for the control group. The mean dose received by the radiotherapist from IRT was 4 {mu}Sv/treatment. The doses to the other staff members were completely negligible. Conclusion: Our results have shown that the patient and personnel doses in {gamma}-IRT remain at an acceptable level. The patient dose from IRT was within the variations in dose from the accompanying interventional X-rays.

Thierens, Hubert [Department of Medical Physics and Radiation Protection, Ghent University, Ghent (Belgium)]. E-mail: hubert.thierens@Ughent.be; Reynaert, Nick [Department of Medical Physics and Radiation Protection, Ghent University, Ghent (Belgium); Bacher, Klaus [Department of Medical Physics and Radiation Protection, Ghent University, Ghent (Belgium); Eijkeren, Marc van [Department of Radiotherapy, Ghent University Hospital, Ghent (Belgium); Taeymans, Yves [Department of Cardiology, Ghent University Hospital, Ghent (Belgium)

2004-10-01

222

Radiative higgs boson decays H {yields} f{anti f}{gamma}  

SciTech Connect

Higgs boson radiative decays of the form H {r_arrow} f{ovr f}{gamma} are calculated in the Standard Model using the complete one-loop expressions for the decay amplitudes. Contributions to the radiative width from leptons and light quarks are given. We also present e{ovr e} invariant mass distributions for H {r_arrow} e{ovr e}{gamma}, which illustrate the importance of the photon pole contribution and the effects of the box diagrams. 4 refs., 6 figs.

Abbasabadi, A. [Department of Physical Science, Ferris State Univ., Big Rapids, MI (United States). Coll. of Technology; Bowser-Chao, D.; Repko, W.W. [Michigan State Univ., East Lansing, MI (United States); Dicus, D.A. [Texas Univ., Austin, TX (United States). Center for Particle Physics

1996-10-10

223

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

SciTech Connect

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

Silveira, M. A. G.; Moreira, R. H.; Bellini, B. S. [Centro Universitario da FEI, Sao Bernardo do Campo, Sao Paulo (Brazil); Medina, N. H.; Aguiar, V. A. P. [Instituto de Fisica da Universidade de Sao Paulo, Sao Paulo (Brazil)

2010-08-04

224

Gamma Radiation Effects on Tritium Permeation Through Stainless Steel.  

National Technical Information Service (NTIS)

It was found that in the presence of excess H sub 2 , the higher gamma-irradiation intensity exhibited slightly higher permeation rates of tritium. When the walls of the permeation tube and the HT were highly oxidized, the permeation rates were much more ...

G. R. Longhurst G. A. Deis P. Y. Hsu L. G. Miller R. A. Causey

1983-01-01

225

Radiation-Induced Edema after Gamma Knife Treatment for Meningiomas  

Microsoft Academic Search

A retrospective study was performed to analyze some parameters in a consecutive series of 35 Gamma Knife treatments in 34 patients with benign meningiomas. The minimum dose to the tumors was never less than 12 Gy. The follow-up period was from 1 to 3 years. A semiquantitative method of tumor volume assessment was used to measure the tumor response to

J. C. Ganz; O. Schrttner; G. Pendl

1996-01-01

226

Neutron and gamma radiation effects in proton exchanged optical waveguides.  

PubMed

The effect of neutron and gamma ray irradiations on the optical properties of proton exchanged Z-cut lithium niobate optical planar waveguides were investigated. The damage thresholds were found by optical characterization for waveguides exchanged either in pure or diluted proton source. PMID:19451950

Passaro, Vittorio; Armenise, Mario

2002-09-01

227

Production of hydrogel wound dressings using gamma radiation  

Microsoft Academic Search

Hydrogel wound dressings have been prepared using the gamma rays irradiation technique. The dressings are composed of poly(vinyl pyrrolidone) (PVP), poly(ethylene glycol) (PEG) and agar. The influence of some process parameters on the properties of the dressings has been investigated as: the gel fraction, maximum swelling, swelling kinetics, and mechanical properties. The gel fraction increases with increasing PVP concentration due

Z. Ajji; I. Othman; J. M. Rosiak

2005-01-01

228

Cosmic gamma Radiation of Ultra High Energy of Primordial Origin.  

National Technical Information Service (NTIS)

The quantum mechanical effects near a collapsing black hole as shown by Stephen W. Hawking in 1974 to produce streaming particles through tunneling effect was explored in the context of cosmic gamma ray production. In this thesis, we show the possible pro...

1984-01-01

229

Application of Gamma-Ray Diffusion Theory to Radiation Dosimetry.  

National Technical Information Service (NTIS)

The diffusion equation governing gamma-ray transport has been evaluated in this study by means of random sampling and records of photon trajectories in tissue-like materials obtained for photon sources ranging in energy from 20 to 2750 keV. The records of...

W. H. Ellett

1969-01-01

230

Responses to the low-level-radiation controversy  

SciTech Connect

Some data sets dealing with the hazards of low-level radiation are discussed. It is concluded that none of these reports, individually or collectively, changes appreciably or even significantly the evaluations of possible low-level radiation effects that have been made by several authoritative national and international groups. (ACR)

Bond, V.P.

1981-10-07

231

Stability of a salicylate-based poly(anhydride-ester) to electron beam and gamma radiation  

PubMed Central

The effect of electron beam and gamma radiation on the physicochemical properties of a salicylate-based poly(anhydride-ester) was studied by exposing polymers to 0 (control), 25 and 50 kGy. After radiation exposure, salicylic acid release in vitro was monitored to assess any changes in drug release profiles. Molecular weight, glass transition temperature and decomposition temperature were evaluated for polymer chain scission and/or crosslinking as well as changes in thermal properties. Proton nuclear magnetic resonance and infrared spectroscopies were also used to determine polymer degradation and/or chain scission. In vitro cell studies were performed to identify cytocompatibility following radiation exposure. These studies demonstrate that the physicochemical properties of the polymer are not substantially affected by exposure to electron beam and gamma radiation.

Rosario-Melendez, Roselin; Lavelle, Linda; Bodnar, Stanko; Halperin, Frederick; Harper, Ike; Griffin, Jeremy; Uhrich, Kathryn E.

2011-01-01

232

Ionizing radiation induced changes in phenotype, photosynthetic pigments and free polyamine levels in Vigna radiata (L.) Wilczek.  

PubMed

Effects of gamma rays on the free polyamine (PA) levels were studied in Vigna radiata (L.) Wilczek. Seeds exposed to different doses of gamma rays were checked for damage on phenotype, germination frequency and alteration in photosynthetic pigments. Free polyamine levels were estimated from seeds irradiated in dry and water imbibed conditions. Polyamine levels of seedlings grown from irradiated seeds, and irradiated seedlings from unexposed seeds were also measured. Damage caused by gamma irradiation resulted in decrease in final germination percentage and seedling height. Photosynthetic pigments decreased in a dose dependent manner as marker of stress. Polyamines decreased in irradiated dry seeds and in seedlings grown from irradiated seeds. Radiation stress induced increase in free polyamines was seen in irradiated imbibed seeds and irradiated seedlings. Response of polyamines towards gamma rays is dependent on the stage of the life cycle of the plant. PMID:23454839

Sengupta, Mandar; Chakraborty, Anindita; Raychaudhuri, Sarmistha Sen

2013-02-06

233

Quercetin ameliorates gamma radiation-induced DNA damage and biochemical changes in human peripheral blood lymphocytes  

Microsoft Academic Search

We investigated the radioprotective efficacy of quercetin (QN), a naturally occurring flavonoid against gamma radiation-induced damage in human peripheral blood lymphocytes and plasmid DNA. In plasmid study, QN at different concentrations (3, 6, 12, 24 and 48?M) were pre-incubated with plasmid DNA for 1h followed by exposure of 6Gy radiation. Among all concentrations of QN used, 24?M showed optimum radioprotective

Nagarajan Devipriya; Adluri Ram Sudheer; Marimuthu Srinivasan; Venugopal P. Menon

2008-01-01

234

Effect of gamma radiation on the characteristics of gallium nitride HEMT heterostructures  

Microsoft Academic Search

The influence of gamma radiation from a Co60 source on some characteristics of AlGaN\\/GaN HEMT heterostructures has been studied. The dose dependence of the total source\\u000a and drain resistances is determined using a modified graphical-analytical method for calculation of the characteristic resistances\\u000a of HEMTs. The contacts exhibit a significant radiation-stimulated degradation, which detrimentally affects the transistor\\u000a operation and may account

A. M. Kurakin

2003-01-01

235

Gamma radiation-induced heritable mutations at repetitive DNA loci in out-bred mice  

Microsoft Academic Search

Recent studies have shown that expanded-simple-tandem-repeat (ESTR) DNA loci are efficient genetic markers for detecting radiation-induced germline mutations in mice. Dose responses following irradiation, however, have only been characterized in a small number of inbred mouse strains, and no studies have applied ESTRs to examine potential modifiers of radiation risk, such as adaptive response. We gamma-irradiated groups of male out-bred

C. M. Somers; R. Sharma; J. S. Quinn; D. R. Boreham

2004-01-01

236

Radiation detection system for portable gamma-ray spectroscopy  

DOEpatents

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

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

2006-06-20

237

Multilayer optics for x-ray and gamma radiation  

Microsoft Academic Search

We report the experimental results on production of multilayer soft x-ray and EUV mirrors and their application in x-ray spectroscopy and fluorescence analysis, as well as for development of EUV lithographic and x-ray microscopic devices and soft x-ray point sources. The problem of the production and the investigation of short-period x-ray multilayers and multilayer (gamma) -filters is discussed.

S. S. Andreev; Sergey V. Gaponov; Nikolai N. Salashchenko; E. A. Shamov; Leonid A. Shmaenok; S. V. Bobashev; D. M. Simanovskii; Eugene N. Ragozin

1998-01-01

238

Papain incorporated chitin dressings for wound debridement sterilized by gamma radiation  

NASA Astrophysics Data System (ADS)

Wound debridement is essential for the removal of necrotic or nonviable tissue from the wound surface to create an environment conducive to healing. Nonsurgical enzymatic debridement is an attractive method due to its effectiveness and ease of use. Papain is a proteolytic enzyme derived from the fruit of Carica papaya and is capable of breaking down a variety of necrotic tissue substrates. The present study was focused on the use of gamma radiation for sterilization of papain dressing with wound debriding activity. Membranes with papain were prepared using 0.5% chitin in lithium chloride/dimethylacetamide solvent and sterilized by gamma radiation. Fluid absorption capacity of chitin-papain membranes without glycerol was 14.306.57% in 6 h. Incorporation of glycerol resulted in significant (p<0.001) increase in the absorption capacity. Moisture vapour transmission rate of the membranes was 4285.77455.61 g/m2/24 h at 24 h. Gamma irradiation at 25 kGy was found suitable for sterilization of the dressings. Infrared (IR) spectral scanning has shown that papain was stable on gamma irradiation at 25-35 kGy. The irradiated chitin-papain membranes were impermeable to different bacterial strains and also exhibited strong bactericidal action against both Gram-positive and Gram-negative bacteria. The fluid handling characteristics and the antimicrobial properties of chitin-papain membranes sterilized by gamma radiation were found suitable for use as wound dressing with debriding activity.

Singh, Durgeshwer; Singh, Rita

2012-11-01

239

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

PubMed

In the present study, we investigated the physicochemical and functional properties of lotus seed flour exposed to low and high doses of gamma-radiation (0-30 kGy; the dose recommended for quarantine and hygienic purposes). The results indicated raw seed flour to be rich in nutrients with minimal quantities of antinutritional factors. Irradiation resulted in a dose-dependent increase in some of the proximal constituents. The raw and gamma-irradiated seeds meet the Food and Agricultural Organization-World Health Organization recommended pattern of essential amino acids. Some of the antinutritional factors (phytic acid, total phenolics, and tannins) were lowered with gamma-irradiation, while the seed flours were devoid of lectins, L-3,4-dihydroxyphenylalanine, and polonium-210. The functional properties of the seed flour were significantly improved with gamma-radiation. gamma-radiation selectively preserved or improved the desired nutritional and functional traits of lotus seeds, thus ensuring a safe production of appropriate nutraceutically valued products. PMID:19778060

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

2009-10-28

240

Results of Calculations of External gamma Radiation Exposure Rates from Local Fallout and the Related Radionuclide Compositions of Selected US Pacific Events.  

National Technical Information Service (NTIS)

This report presents data on calculated gamma radiation exposure rates and local surface deposition of related radionuclides resulting from selected US Pacific events. Results of the calculations of relative external gamma radiation exposure rate and rela...

H. G. Hicks

1984-01-01

241

Californium252 ( 252 Cf) versus Conventional Gamma Radiation in the Brachytherapy of Advanced Cervical Carcinoma  

Microsoft Academic Search

Background: When photon radiotherapy is applied to cervical carcinoma, it has been observed that, despite important progress in radiotherapy technique and quality assurance, no significant increase in curative rates has resulted. Among the reasons for this is the varying radiosensitivity of different tumor subpopulations. Treatment with californium-252 (252Cf), as a source of gamma\\/neutron radiation in brachytherapy, provides properties and new

Ta?o Ta?ev; Blanka Pt?kov; Vratislav Strnad

2003-01-01

242

CALIBRATION AND USE OF A SYSTEM OF FILM BADGES FOR PERSONAL DOSIMETRY FOR GAMMA RADIATION  

Microsoft Academic Search

A method of calibration of a film-badge system for gamma radiations from ; radioisotopes is described. The criteria for the choice of emulsion and the ; system adopted for correcting the response from the energy dependence are shown. ; The energy dependence is corrected by a metallic filter, made by 1 mm of tin and ; 0.5 mm of lead

P. Amadesi; N. Grimellini; G. Guenzi; O. Rimondi

1959-01-01

243

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

PubMed Central

Purpose The aim of this work was to use metabolomics to evaluate sebum as a source of biomarkers for gamma-radiation exposure in the rat, and potentially in man. Proof of concept of radiation metabolomics was previously demonstrated in both mouse and rat urine, from the radiation dose- and time-dependent excretion of a set of urinary biomarkers. Materials and methods Rats were gamma-irradiated (3 Gy) or sham irradiated and groups of rats were euthanised at 1 h or 24 h post-irradiation. Sebum was collected by multiple washings of the carcasses with acetone. Nonpolar lipids were extracted, methylated, separated and quantitated using gas chromatography-mass spectrometry (GCMS). Metabolomic analysis of the GCMS data was performed using both orthogonal projection to latent structures-discriminant analysis and random forests machine learning algorithm. Results Irradiation did not alter sebum production. A total of 35 lipids were identified in rat sebum, 29 fatty acids, five fatty aldehydes, and cholesterol. Metabolomics showed that three fatty acids, palmitic, 2-hydroxypalmitic, and stearic acids were potential biomarkers. Sebaceous palmitic acid was marginally statistically significantly elevated (7.58.4%) at 24 h post-irradiation. Conclusions Rat sebaceous gland appears refractory to 3 Gy gamma-irradiation. Unfortunately, collection of sebum shortly after gamma-irradiation is unlikely to form the basis of high-throughput non-invasive radiation biodosimetry in man.

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

2013-01-01

244

Effect of Gamma and UV Radiation on Properties of EPDM\\/GTR\\/HDPE Blends  

Microsoft Academic Search

Ethylene propylene dine monomer (EPDM) was blended with both ground tire rubber (GTR) and high-density polyethylene (HDPE) prepared at different ratios and then exposed to gamma and ultraviolet radiations. The mechanical, physical, and thermal properties were investigated with respect to the kind of irradiation and blend compositions. A scanning electron microscope was also used to examine the morphology of the

M. M. Abou Zeid; S. T. Rabie; A. A. Nada; A. M. Khalil; R. H. Hilal

2008-01-01

245

An integrated systems approach for understanding cellular responses to gamma radiation  

Microsoft Academic Search

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

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

2006-01-01

246

Stimulation Effects of gamma Radiation on Mung Bean (Vigna Radiata (L) Wilzcek).  

National Technical Information Service (NTIS)

Mung bean seeds of U-Thong 1 variety were treated with gamma radiation at different doses 0, 5, 10, 15, 20, 25, 30, 50, 75, 100, 200 and 400 gray respectively. Their germination, growth and yield were observed in a greenhouse and in a field. Their chromos...

V. Phadvibulya N. Vanichvattanaramlug S. Pichitporn

1983-01-01

247

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

NASA Astrophysics Data System (ADS)

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

Nunes, Ins; Mesquita, Nuno; Cabo Verde, Sandra; Joo Trigo, Maria; Ferreira, Armando; Manuela Carolino, Maria; Portugal, Antnio; Lusa Botelho, Maria

2012-12-01

248

Caffeic acid protects human peripheral blood lymphocytes against gamma radiation-induced cellular damage.  

PubMed

In the present study, we investigated in vitro radioprotective potential of caffeic acid (CA), a naturally occurring catecholic acid against gamma radiation-induced cellular changes. Different concentrations of CA (5.5, 11, 22, 44, 66, and 88 microM) were incubated with lymphocytes for 30 min prior to gamma-irradiation, and micronuclei (MN) scoring and comet assay were performed to fix the effective concentration of CA against gamma-irradiation. Among all concentrations, 66 microM of CA showed the optimum protection by effectively decreasing the MN frequencies and comet attributes. From the above-mentioned results, 66 microM of CA was selected as the effective concentration and was further used to investigate its radioprotective efficacy. For that purpose, a separate experiment was carried out on the lymphocytes in which lymphocytes were preincubated with CA (66 microM) and were exposed to different doses of radiation (1, 2, 3, and 4 Gy). Genetic damage (MN, dicentric aberration, and comet attributes) and biochemical changes were measured. Gamma-irradiated lymphocytes showed a dose-dependent increase in the genetic damage and thiobarbituric acid reactive substances, accompanied by the significant decrease in the antioxidant status, whereas CA pretreatment positively modulated all the radiation-induced changes through its antioxidant potential. The current study demonstrates that CA is effective in protecting lymphocytes against radiation-induced toxicity and encourages further in vivo study to evaluate radioprotective efficacy of CA. PMID:18561333

Devipriya, Nagarajan; Sudheer, Adluri Ram; Menon, Venugopal P

249

Study on the effect of low doses gamma radiation on mushroom spawn.  

National Technical Information Service (NTIS)

Mushroom spawn (Hybrid-521) was irradiated at room temperature using low doses of gamma radiation (50-600 rad). The spawn was then planted at two stages; first, after 24 hours of irradiation, and second after storage for three weeks at refrigeration tempe...

S. Ajlouni

1993-01-01

250

Split-sting trait in Apis mellifera induced by cobalt 60 gamma radiation.  

National Technical Information Service (NTIS)

The Split-Sting (SS) trait in honey bees, induced by gamma radiation, was discovered by Soares (1975). Bees with this trait are unable to sting, because the parts that compose the sting are separated. Many studies have been done in order to understand thi...

V. L. M. Silva

1993-01-01

251

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

Microsoft Academic Search

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

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

2008-01-01

252

Effects of gamma radiation on a plastic material based on bean protein  

Microsoft Academic Search

The effect of gamma radiation applied to a system used for the preparation of biodegradable plastics was studied. The system was composed of the proteins and glucopolysaccharides previously isolated from Phaseolus vulgaris beans, mixed with glycerol and water as plasticizers. The irradiation of mixtures with doses of 25, 50 and 100 kGy was carried out in two conditions: (a) before

M. E. Gonzalez; E. M. Salmoral; K. Traverso; M. E. Floccari

2002-01-01

253

Death of a classified worker probably caused by overexposure to gamma radiation  

Microsoft Academic Search

This paper describes the case of an industrial radiographer who was seriously overexposed to gamma radiation. The exact circumstances of this exposure were not established but it was concluded that he was repeatedly irradiated probably to a total average whole body dose of at least 10 Gy over several years. Also, a much larger dose to a hand required its

D C Lloyd; A A Edwards; E J Fitzsimons; C D Evans; R Railton; P Jeffrey; T G Williams; A D White; M Ikeya; H Sumitomo

1994-01-01

254

Inactivation and stability of viral diagnostic reagents treated by gamma radiation.  

PubMed

The objective of this study was to apply the pertinent findings from gamma inactivation of virus infectivity to the production of high quality diagnostic reagents. A Gammacell 220 (Atomic Energy of Canada, Ltd., Ottawa, Canada) was used to subject 38 viruses grown in either susceptible tissue cultures or embryonated chicken eggs to various doses of gamma radiation from a cobalt-60 source. The radiation required to reduce viral infectivity was 0.42 to 3.7 megarads (Mrad). The effect of gamma treatment on the antigenic reactivity of reagents for the complement fixation (CF), hemagglutination (HA) and neuraminadase assays was determined. Influenza antigens inactivated with 1.7 Mrad displayed comparable potency, sensitivity, specificity and stability to those inactivated by standard procedures with beta-propiolactone (BPL). Significant inactivation of influenza N1 and B neuraminidase occurred with greater than 2.4 Mrad radiation at temperatures above 4 degrees C. All 38 viruses were inactivated, and CF or HA antigens were prepared successfully. Antigenic potency remained stable with all antigens for 3 years and with 83% after 5 years storage. Influenza HA antigens evaluated after 9 years of storage demonstrated 86% stability. Gamma radiation is safer than chemical inactivation procedures and is reliable and effective replacement for BPL in preparing diagnostic reagents. PMID:2126734

White, L A; Freeman, C Y; Hall, H E; Forrester, B D

1990-10-01

255

Molecular weights and molecular weight distributions of irradiated cellulose fibers by gel permeation chromatography. [. gamma. radiation  

Microsoft Academic Search

Radiation degradation of cellulose fibers was investigated by gel permeation chromatography (GPC). Scoured cotton of Mexican variety (cellulose I), Polynosic rayon (cellulose II), and their microcrystalline celluloses obtained by hydrolysis of the original fibers were irradiated by Co-60 ..gamma..-rays under vacuum or humid conditions. The irradiated samples were then nitrated under nondegradative conditions. The molecular weights and molecular weight distributions

Y. Kusama; E. Kageyama; M. Shimada; Y. Nakamura

1976-01-01

256

Gamma scintillation probe for field use and measurements of radiation background in Puget Sound  

Microsoft Academic Search

A probe containing a 5 x 4-in. NaI( TI) crystal was built for field survey work with a small ship and portable counting equipment. The gamma radiation background was mcas- ured to a depth of 80 m at 3 locations in the lower part of Puget Sound. The count rate dccreascd very rapidly and nonlinearly in the first few meters

CHARLES M. PROCTOR; EMANUEL PAPADOPULOS; RALPH H. FIRMINHAC

1962-01-01

257

Principal Component Analysis of Gamma-Ray Spectra for Radiation Portal Monitors  

Microsoft Academic Search

The scanning of cargo for radiological and nuclear material is vital in detecting the illicit trafficking of such materials. The deployment of technologies such as Radiation Portal Monitors (RPMs) has enabled screening for the presence of gamma and neutron emitting radionuclides.

David Boardman; Mark Reinhard; Alison Flynn

2012-01-01

258

THE BEHAVIOR OF EXPLOSIVES UNDER THE IMPACT OF $gamma$RADIATION. PART I  

Microsoft Academic Search

Smokeless powder (nitrocellulose with various gelatinizing and ; plasticizing agents) was exposed to Co⁶° gamma radiation at dosages ; ranging from 0 to 15 x 10⁶ r and pressures from 0 to 300 mm Hg. The ; stability of the powder under varying doses and pressures was examined. The 4 ; samples studied consisted of powders of (a) gelatinized smokeless

E. Piantanida; M. Piazzi

1960-01-01

259

THE EFFECTS OF GAMMA RADIATION ON JPN PROPELLANT. Memorandum Report No. 122  

Microsoft Academic Search

Strips of JPN propellart were subjected to the gamma radiation of cobalt-; 60 sources at Brooknaven National Laboratory. These strips were chemically ; analyzed and physically tested. Significant changes were observed in the ; viscosity of the nitrocellulose, the available centralites and the stability of ; the propellant. The main transformation product of the ethyl centralitc ; stabilizer was 4-nitrocentralite.

A. Owyang; H. Rosenwasser

1956-01-01

260

77 FR 62267 - Proposed Extension of Existing Information Collection; Gamma Radiation Surveys  

Federal Register 2010, 2011, 2012, 2013

...or solids. Gamma rays penetrate the body and can kill or damage cells in their path which can affect many of the body's organs. The adverse health effects...radiation can vary depending upon the type of cell affected and the extent of...

2012-10-12

261

Can gamma radiation be produced in the electrical environment above thunderstorms?  

Microsoft Academic Search

Calculations indicate that regions above large mesocsale convective systems may be favorable electrical environments for the production of gamma radiation by runaway electrons in bremsstrahlung collisions. It is well known (Gurevich, 1961) that an electric field however small can accelerate an electron continuously until the electric field is larger than the oppposing force of friction. Since the force of friction

Britton Chang; Colin Price

1995-01-01

262

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

263

Effects of low level radiation-what's new?  

PubMed

A comprehensive review of the effects of exposure to low levels of ionizing radiation, BEIR VII-Phase 2: Health Risks From Exposure to Low Levels of Ionizing Radiation, was published in 2006. The BEIR (Biological Effects of Ionizing Radiation) reports are a series of publications by the National Academy of Sciences. The last BEIR report on the effects of low level radiation, BEIR V, was published in 1990. To update the risk estimates for exposure to low levels of ionizing radiation, the BEIR committee reviewed recent epidemiologic studies of the atomic bomb survivors, as well as recent studies of populations exposed to radiation from diagnostic and therapeutic medical studies, from occupational exposures and from exposure due to releases of radioactive materials into the environment. Additional increasingly sophisticated epidemiologic studies continue to be published. BEIR VII reconfirmed that the linear no threshold model is the most practical model to estimate radiation risks, especially for radiation protection purposes. The updated risk estimates have not changed significantly from the BEIR V estimates, but the confidence intervals have narrowed as the result of the availability of additional data. The effects of low doses of radiation should be of particular interest to medical professionals because radiation exposure from diagnostic medical studies is, by far, the largest source of radiation exposure from human activity. One recommendation of the BEIR VII report is to perform epidemiologic studies of patients, especially children, who have been exposed to radiation as part of their care. A large, sophisticated epidemiologic study will likely be able to detect an increase in cancer risk. The purpose of this article is to highlight the contents of this important publication with particular emphasis on what is new. PMID:18662560

Royal, Henry D

2008-09-01

264

Production of hydrogel wound dressings using gamma radiation  

NASA Astrophysics Data System (ADS)

Hydrogel wound dressings have been prepared using the gamma rays irradiation technique. The dressings are composed of poly(vinyl pyrrolidone) (PVP), poly(ethylene glycol) (PEG) and agar. The influence of some process parameters on the properties of the dressings has been investigated as: the gel fraction, maximum swelling, swelling kinetics, and mechanical properties. The gel fraction increases with increasing PVP concentration due to increased crosslink density, and decreases with increasing the PEG concentration. PEG seems to act not only as plasticizer but also to modify the gel properties as gelation% and maximum swelling. The prepared hydrogels dressings could be considered as a good barrier against microbes.

Ajji, Z.; Othman, I.; Rosiak, J. M.

2005-04-01

265

Gamma-irradiated onions as a biological indicator of radiation dose.  

PubMed

Post-irradiation identification and dose estimation are required to assess the radiation-induced effects on living things in any nuclear emergency. In this study, radiation-induced morphological/cytological changes i.e., number of root formation and its length, shooting length, reduction in mitotic index, micronuclei formation and chromosomal aberrations in the root tip cells of gamma-irradiated onions at lower doses (50-2000 cGy) are reported. The capabilities of this biological species to store the radiation-induced information are also studied. PMID:11762393

Vaijapurkar, S G; Agarwal, D; Chaudhuri, S K; Senwar, K R; Bhatnagar, P K

2001-10-01

266

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

NASA Astrophysics Data System (ADS)

As insects increase in radiotolerance as they develop and usually several developmental stages of the pest may be present in the fresh shipped commodity, it is important to know the radiation susceptibility of the stages of the target insect before the establishment of ionizing radiation quarantine treatments. This study was performed to determine the radiotolerance of eggs of the oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), to gamma radiation. This species is considered as one of the most serious worldwide pests for temperate fruits, especially peaches. Eggs (12 h old) were exposed to 0 (control), 25, 35, 50, 75, 100, 125 and 150 Gy of gamma radiation. Surviving larvae were allowed to feed on an artificial diet. Three days after irradiation, it was verified that larvaes cephalic capsules were significantly affected by gamma radiation, and the estimated mean LD90 and LD99 were 66.3 Gy and 125.8 Gy, respectively. Oriental fruit moth eggs revealed to be quite radiosensitive and very low doses as 50 Gy were sufficient to disrupt G. molesta embryogenesis. At 25 Gy, only male adults originated from the surviving larvae and, after mating with untreated fertile females, shown to be sterile.

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

2010-10-01

267

Issues in the control of low?level radiation exposure  

Microsoft Academic Search

The carcinogenic risks of exposure to low level ionizing radiation used by the International Commission on Radiation Protection (ICRP) have been challenged as being, at the same time, both too high and too low. This paper explains that the epidemiological evidence will always be limited at low doses, so that understanding the cellular mechanisms of carcinogenesis is increasingly important to

Roger H Clarke

2000-01-01

268

Solid state polymerization of acrylamide initiated by gamma radiation  

Microsoft Academic Search

The solid-state polymerization of acrylamide, both in a radiation field ; and after removal from the field, is shown to proceed by an unusual kinetic ; mechanism. The usual steady state assumption is found to be inadequate because ; there seems to be no free radical termination (in the normal sense) involved. ; These results are consistent with the view

B. Baysal; G. Adler; D. Ballantine; P. Colombo

1960-01-01

269

Gamma radiation sensitivity of foodborne pathogens on meat and poultry  

SciTech Connect

Several factors have been identified that may affect the responses of foodborne pathogens to ionizing radiation. Among these are the temperature and atmosphere during the process of irradiation; the medium in which the pathogen is suspended; and the genus, species, serovar, and physiological state of the organism. In addition to these factors, variations in {open_quotes}apparent{close_quotes} radiation sensitivity of bacteria may occur because of the incubation conditions and media used to estimate the number of surviving colony-forming units. Both incubation temperature and culture media frequently affect the ability of injured bacteria to recover. Because there are so many possible variables, it is often difficult to compare data on the radiation sensitivity of foodborne pathogens from different studies. The objectives of the studies reported here were to compare the radiation sensitivities of Bacillus cereus on beef, beef gravy, chicken, pork, and turkey; and of Escherichia coli 0157:H7, Listeria monocytogenes, Salmonella, and Staphylococcus aureus on beef, pork, lamb, turkey breast, and turkey leg meats. Examples of the effects of serovar, irradiation temperature, growth phase, and atmosphere during irradiation were also examined.

Thayer, D.W.; Boyd, G. [USDA, Philadelphia, PA (United States)

1994-12-31

270

Inactivation of foodborne pathogens on seafood by gamma radiation  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ionizing radiation is used on a global basis to improve the phytosanitary and microbial safety and shelf-life of foods. In recent years progress has been made in the commercial application of irradiation to sterilize destructive invasive insects and to irradiate produce to improve its microbiologica...

271

Gamma radiation in the reduction of Salmonella spp. inoculated on minimally processed watercress (Nasturtium officinalis)  

NASA Astrophysics Data System (ADS)

Consumer attitudes towards foods have changed in the last two decades increasing requirements for freshlike products. Consequently, less extreme treatments or additives are being required. Minimally processed foods have freshlike characteristics and satisfy this new consumer demand. Besides freshness, the minimally processing also provide convenience required by the market. Salad vegetables can be source of pathogen such as Salmonella, Escherichia coli O157:H7, Shigella spp. The minimal processing does not reduce the levels of pathogenic microorganisms to safe levels. Therefore, this study was carried out in order to improve the microbiological safety and the shelf-life of minimally processed vegetables using gamma radiation. Minimally processed watercress inoculated with a cocktail of Salmonella spp was exposed to 0.0, 0.2, 0.5, 0.7, 1.0, 1.2 and 1.5kGy. Irradiated samples were diluted 1:10 in saline peptone water and plated onto tryptic soy agar that were incubated at 37C/24h. D10 values for Salmonella spp. inoculated in watercress varied from 0.29 to 0.43kGy. Therefore, a dose of 1.7kGy will reduce Salmonella population in watercress by 4log10. The shelf-life was increased by 11/2 day when the product was exposed to 1kGy.

Martins, C. G.; Behrens, J. H.; Destro, M. T.; Franco, B. D. G. M.; Vizeu, D. M.; Hutzler, B.; Landgraf, M.

2004-09-01

272

Evaluation of phenolic compounds in mat (Ilex paraguariensis) processed by gamma radiation  

NASA Astrophysics Data System (ADS)

The radiation food processing has been demonstrating great effectiveness in the attack of pathogenic agents, while little compromising nutritional value and sensorial properties of foods. The mat (Ilex paraguariensis), widely consumed product in South America, generally in the form of infusions with hot or cold water, calls of chimarro or terer, it is cited in literature as one of the best sources phenolic compounds. The antioxidants action of these constituent has been related to the protection of the organism against the free radicals, generated in alive, currently responsible for the sprouting of some degenerative illness as cancer, arteriosclerosis, rheumatic arthritis and cardiovascular clutters among others. The objective of that work was to evaluate the action of the processing for gamma radiation in phenolic compounds of terer beverage in the doses of 0, 3, 5, 7 and 10 kGy. The observed results do not demonstrate significant alterations in phenolic compounds of terer beverage processed by gamma radiation.

Furgeri, C.; Nunes, T. C. F.; Fanaro, G. B.; Souza, M. F. F.; Bastos, D. H. M.; Villavicencio, A. L. C. H.

2009-07-01

273

High-total-dose gamma and neutron radiation tolerance of VCSEL assemblies  

NASA Astrophysics Data System (ADS)

Optical fiber technology is seriously considered for communication and monitoring applications during the operation and maintenance of future thermonuclear fusion reactors. Their environment is characterized, in particular, by possibly high gamma dose-rates and total doses in excess of 10 MGy. In addition, the maintenance equipment might be stored in close vicinity of the reactor during its operation and therefore the communication devices might also be exposed to a substantial neutron fluence. The feasibility of applying photonic technology in these radiation fields therefore needs to be assessed. Whereas many reports deal with the radiation behavior of a variety of fiber-optic devices, only little information is available on the radiation tolerance at high total dose (e.g. > 1 MGy). We describe our recent results obtained on vertical-cavity surface-emitting laser (VCSEL) assemblies. We have conducted high total dose (up to 20 MGy) irradiation experiments on such devices, which confirmed their excellent gamma radiation hardness. The optical power loss at nominal forward current was less than 2 dB and the threshold current remained unaltered. We have also irradiated these devices with neutrons inside the BR1 reactor (SCKCEN, Mol, Belgium) up to a total fluence on the order of 1015 ncm-2. The response of VCSELs to neutrons is, as expected, different from that to gamma radiation. VCSELs previously exposed to gamma rays exhibited an accelerated degradation under neutron radiation compared to not pre-irradiated devices. The beneficial effect of applying a continuous forward bias to the VCSELs is also evidenced.

Berghmans, Francis; Van Uffelen, Marco; Decrton, Marc C.

2002-09-01

274

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

PubMed

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

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

2010-05-01

275

Development of Detectors for Measurement of Neutron and Gamma-radiation from Laser-Produced Plasma  

NASA Astrophysics Data System (ADS)

The paper describes the development of the detectors widely used in the nuclear physics for measurement of neutron and gamma-radiation in laser-produced plasma. Under investigation is plasmas generated by action on solid-state target by radiation from picosecond terawatt Nd-glass laser having intensity of 10 to the power 16 10 to the power 18 Watt per centimeter squared. Peculiarities of such plasmas have called for modernization of conventional methods and detectors for measurement of neutron and gamma-radiation. Diagnostic methods imply use of scintillation counters based on stilbene crystal, scintillation gamma-spectrometer based on NaI(Tl) crystal and proportional counters based on He III. The paper as well presents results of the experimental investigation on generation of gamma-quanta and neutrons in laser-produced plasma. The experimental methods and detectors described in the paper provide a basis for studies on a wide spectrum of atomic and nuclear processes going in the laser-produced dense plasmas. The present work was supported by International Science and Technology Center under Project number 856.

Matafonov, Anatoly

2000-03-01

276

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

SciTech Connect

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

Not Available

1989-01-01

277

Network-level fallout radiation effects assessment. Final report  

SciTech Connect

National Security calls for the ability to maintain communication capabilities in times of national disaster, which could include a nuclear attack. Nuclear detonation has two basic by-products for which telecommunication equipments are susceptible to damage. These are electromagnetic pulse (EMP) and fallout radiation. The purposes of the EMP Mitigation Program are to analyze and to lessen the effects of EMP and fallout radiation on national telecommunications resources. Fallout radiation occurs after the initial intense high-frequency EMP, and is the subject of this analysis. Fallout radiation is the residual radiation that remains in the atmosphere after a nuclear blast, and which can be carried by weather conditions to locations far from the detonation point. This analysis focuses on the effects of fallout radiation on the telecommunications network of the American Telephone and Telegraph Co. (AT and T). This assessment of AT and T-network's communications-capabilities uses a network-level approach to assess fallout-radiation effects on the network's performance. The approach used was developed for assessing network-level EMP effects on Public Switched Network communication capabilities. Details are given on how EMP assessments utilize this method. Equipment-level fallout-radiation survivability data is also required.

Not Available

1991-05-01

278

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

PubMed

We reviewed the calibration procedures of gamma-ray spectrometry with particular emphasis to factors that affect accuracy, detection limits and background radiation in field measurements for dosimetric and radon potential mapping. Gamma-ray spectra were acquired in western Liguria (Italy). The energy windows investigated are centred on the photopeaks of (214)Bi (1.76 MeV), (208)Tl (2.62 MeV) and (40)K (1.46 MeV). The inferred absorbed dose rate and the radon flux are estimated to be lower than 60 nGy h(-1) and 22 Bq m(-2)h(-1), respectively. PMID:19249218

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

2009-01-24

279

Assessment of external gamma exposure and radon levels in a dwelling constructed with phosphogypsum plates.  

PubMed

Phosphogypsum, a fertilizer industry by-product, is being worldwide stockpiled, posing environmental concerns. Since this material contains natural radionuclides in significant concentrations, its use as a building material has radiological implications. In order to confirm the feasibility of the use of a new material mainly composed by phosphogypsum, an experimental house was built, having some of its rooms entirely lined with this material. Measurements of samples of phosphogypsum plates from different origins resulted in values of 0.2 to 2.6 for the external radiation index, thus justifying a more detailed investigation. In this paper, the application of a previously developed computational model to forecast external doses indoors is described. A comprehensive radiological evaluation is being performed, including measurement of the external gamma exposure and radon concentrations in one of the rooms of the house. The results show that the annual increment in the effective dose to an inhabitant of the house will remain below the 1 mSv limit for every reasonable scenario. The radon measurements were carried out over a period of 18 months, in order to determine the long-term average levels of the indoor radon concentrations. The results obtained are below 200 Bq m(-3), the recommended investigation level for radon. PMID:21458158

Mduar, M F; Campos, M P; Mazzilli, B P; Villaverde, F L

2011-03-12

280

Dose quantities and instrumentation for measuring environmental gamma radiation during emergencies  

SciTech Connect

The dosimetry for exposure to gamma radiation in the environment is reviewed, including the factors used to convert measurements of traceable quantities to effective dose equivalent. A value of 0.70 Sv Gy-1 is widely used to convert air kerma or absorbed dose-to-air to effective dose equivalent, but recent work shows that a value of 0.86 Sv Gy-1 is more appropriate for deposited radionuclides. The arguments are reviewed and the implications of using operational dose equivalent quantities defined by the International Commission on Radiation Units and Measurements are considered. For planar deposited sources in the environment, it is shown that the use of ambient dose equivalent quantities without applying conversion factors, could significantly overestimate effective dose equivalent. In contrast, the adoption of the new effective dose quantity defined by the International Commission on Radiological Protection in Publication 60 will have a small impact on conversion factors for gamma radiation in the environment. Practical aspects of measurement are also considered, and five instruments suitable for measuring environmental gamma radiation have been evaluated in the laboratory and in field tests. The instruments include models with scintillation detectors, a Geiger-Mueller detector, and a high-pressure ionization chamber, the choice being influenced by those commonly used in European Community countries for routine and emergency monitoring. The main disadvantage of all the instruments is the lack of spectral information, so a straightforward emergency instrument capable of discriminating between natural and artificial radionuclides has also been evaluated.

Clark, M.J.; Burgess, P.H.; McClure, D.R. (National Radiological Protection Board, Oxfordshire (United Kingdom))

1993-05-01

281

Dose quantities and instrumentation for measuring environmental gamma radiation during emergencies.  

PubMed

The dosimetry for exposure to gamma radiation in the environment is reviewed, including the factors used to convert measurements of traceable quantities to effective dose equivalent. A value of 0.70 Sv Gy-1 is widely used to convert air kerma or absorbed dose-to-air to effective dose equivalent, but recent work shows that a value of 0.86 Sv Gy-1 is more appropriate for deposited radionuclides. The arguments are reviewed and the implications of using operational dose equivalent quantities defined by the International Commission on Radiation Units and Measurements are considered. For planar deposited sources in the environment, it is shown that the use of ambient dose equivalent quantities without applying conversion factors, could significantly overestimate effective dose equivalent. In contrast, the adoption of the new effective dose quantity defined by the International Commission on Radiological Protection in Publication 60 will have a small impact on conversion factors for gamma radiation in the environment. Practical aspects of measurement are also considered, and five instruments suitable for measuring environmental gamma radiation have been evaluated in the laboratory and in field tests. The instruments include models with scintillation detectors, a Geiger-Mller detector, and a high-pressure ionization chamber, the choice being influenced by those commonly used in European Community countries for routine and emergency monitoring. The main disadvantage of all the instruments is the lack of spectral information, so a straightforward emergency instrument capable of discriminating between natural and artificial radionuclides has also been evaluated. PMID:8491600

Clark, M J; Burgess, P H; McClure, D R

1993-05-01

282

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

DOEpatents

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

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

1987-02-27

283

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

DOEpatents

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

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

1989-01-01

284

Radiation-induced reductions in transporter mRNA levels parallel reductions in intestinal sugar transport  

PubMed Central

More than a century ago, ionizing radiation was observed to damage the radiosensitive small intestine. Although a large number of studies has since shown that radiation reduces rates of intestinal digestion and absorption of nutrients, no study has determined whether radiation affects mRNA expression and dietary regulation of nutrient transporters. Since radiation generates free radicals and disrupts DNA replication, we tested the hypotheses that at doses known to reduce sugar absorption, radiation decreases the mRNA abundance of sugar transporters SGLT1 and GLUT5, prevents substrate regulation of sugar transporter expression, and causes reductions in sugar absorption that can be prevented by consumption of the antioxidant vitamin A, previously shown by us to radioprotect the testes. Mice were acutely irradiated with 137Cs gamma rays at doses of 0, 7, 8.5, or 10 Gy over the whole body. Mice were fed with vitamin A-supplemented diet (100 the control diet) for 5 days prior to irradiation after which the diet was continued until death. Intestinal sugar transport was studied at days 2, 5, 8, and 14 postirradiation. By day 8, d-glucose uptake decreased by ?1020% and d-fructose uptake by 2585%. With increasing radiation dose, the quantity of heterogeneous nuclear RNA increased for both transporters, whereas mRNA levels decreased, paralleling reductions in transport. Enterocytes of mice fed the vitamin A supplement had ? 6-fold retinol concentrations than those of mice fed control diets, confirming considerable intestinal vitamin A uptake. However, vitamin A supplementation had no effect on clinical or transport parameters and afforded no protection against radiation-induced changes in intestinal sugar transport. Radiation markedly reduced GLUT5 activity and mRNA abundance, but high-d-fructose diets enhanced GLUT5 activity and mRNA expression in both unirradiated and irradiated mice. In conclusion, the effect of radiation may be posttranscriptional, and radiation-damaged intestines can still respond to dietary stimuli.

Roche, Marjolaine; Neti, Prasad V. S. V.; Kemp, Francis W.; Agrawal, Amit; Attanasio, Alicia; Douard, Veronique; Muduli, Anjali; Azzam, Edouard I.; Norkus, Edward; Brimacombe, Michael; Howell, Roger W.

2010-01-01

285

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

SciTech Connect

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

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

1989-11-01

286

Effects of gamma radiation on Clostridium botulinum type E under various parameters  

SciTech Connect

Spores of Clostridium botulinum type E strain Eklund (Eklund) was irradiated with gamma radiation and its recovery was tested on the tryptone-peptone-glucose-yeast extract-agar (TPGYA) containing various levels of NaCl and Na-thioglycollate. The presence of 0.5% or more NaCl in the media decreased the viable counts, while Na-thioglycollate of up to 0.15% did not affect the recovery of both irradiated and non-irradiated spores. Eklund spores were also irradiated under air (21% O/sub 2/), N/sub 2/O and N/sub 2/, with or without the additive of one of the following agents (additive/concentration): disodium ethylenediaminetetraacetate (EDTA), 0.01 M; t-butanol, 0.1 M; NaCl, 0.01 M; catalyze, 10 mg/ml and DL-cysteine, 0.1 mM. Radiation process was most effective in destroying the spores when carried out under air (21% O/sub 2/), followed by N/sub 2/O and N/sub 2/. Among the additives tested, EDTA was the most efficient protector followed by t-butanol when irradiation process was carried under N/sub 2/O and N/sub 2/ gas environment. Catalase and DL-cysteine sensitized the spores when irradiated under N/sub 2/O and N/sub 2/, while NaCl only sensitized under N/sub 2/. Spores kept frozen at -75/sup 0/C for 30 days but thawed prior to irradiation were more sensitive to radiation damage than freshly prepared spores. Radiation resistance of the spores increased when 15% glycerol was added to the phosphate bugger (0.06 M, pH 7.0) and used as suspending media. When the concentration of the spore increased from 10/sup 6//ml to 10/sup 11//ml, the radiosensitivities also increased. Seven strains of C. botulinum type E were screened for plasmids by agarose gel electrophoresis.

Lim, Y.H.

1986-01-01

287

Low-level radiation effects: a fact book  

SciTech Connect

Low Level Raidation Effects: A Fact Book, prepared by the Society of Nuclear Medicine Subcommittee on the Risks of Low-Level Ionizing Radiation, attempts to examine the health effects of small doses of radiation. For immediate questions, this work provides a well-organized brief summary of recent radiologic data from refereed scientific literature and from the publications of advisory groups such as the National Council of Radiation Protection and Measurement (NCRP), the International Commission on Radiological Protection (ICRP), the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), and the National Academy of Sciences (NAS). Since it consists almost entirely of tables and graphs from the above-mentioned sources along with summary paragraphs, the Fact Book is very useful in the preparation of lectures. The book is divided into seven sections. Chapter One, Glossary, Units and Conversion Factors, is useful because nearly all data given in the rest of the book is in conventional units and should be converted to SI units for future technical audiences. Chapter 2, Radiobiology, covers the fundamental principles of the field. Chapter 3, Radiation Doses, can be used to help an audience appreciate the relative magnitudes of radiation exposures they may read about or encounter. Chapter 4, Late Somatic Effects of Low Doses of Ionizing Radiation, gives data concerning cancer induction and embryonic effects, and Chapter 5 provides data on genetic effects Chapter 6, Risks, Statistical Facts and Public Perception can be used to compare the risks of radiation exposure with more commonly encountered risks.

Brill, A.B.; Adelstein, S.J.; Saenger, E.L.; Webster, E.W.

1982-01-01

288

Zener diodes for gamma-ray radiation dosimetry  

SciTech Connect

The fundamental properties of Zener diodes and junction field-effect transistors have been studied to use them as a relative dose monitor or a radiation-damage monitor. The response observed at liquid nitrogen temperature, i.e., radiation-induced change in the breakdown voltage of the Zener diode, or change in the breakdown voltage of the pn junction between the gate and the channel (or between the substrate gate and the channel) of the junction field-effect transistor as a function of dose, has shown good linearity. The diode of Toshiba 05Z18 has been found to be useful for doses between 1 and 100 MGy with the fading of response less than 10% for 100 h after irradiation. On the other hand, the junction field-effect transistors of Mitsubishi 2SK33 has proved useful in the region between 0.1 and 10 MGy with the build-up of responses less than 5% for 100 h. The response of both the junction field-effect transistor and the Zener diode has shown a reproducibility within {+-}5. For fast readout, a simple system consisting essentially of a constant-current source together with a digital voltmeter has been constructed. For practical application, the devices from which soldered leads are taken off can be used simply to measure relative doses in various materials.

Nakamura, Shigeki; Okamoto, Shinichi [Univ. of Osaka Prefecture, Sakai (Japan). Research Institute for Advanced Science and Technology

1995-04-01

289

Current response of a TlBr detector to {sup 137}Cs {gamma}-ray radiation  

SciTech Connect

The current response of a TlBr detector to {sup 137}Cs {gamma}-ray radiation has been studied in the dose-rate range 0.033-3.84 Gy/min and within the voltage range 1-300 V; the detectors are based on pure and doped TlBr crystals grown from the melt by the Bridgman-Stockbarger method. The mass fraction of Pb or Ca introduced into the TlBr crystals was 1-10 ppm for Pb and 150 ppm for Ca. The current response of nominally undoped TlBr samples was nearly linear over two decades of studied dose rates. Deep hole levels associated with cationic vacancies V{sub c}{sup -} determine the dependence of the current response on the voltage in the high electric fields. The parameters of the carriers' transport {mu}{tau} are determined. The TlBr crystals grown in vacuum and in the bromine vapor exhibit a large mobility-lifetime product of 4.3 Multiplication-Sign 10{sup -4} and 6.4 Multiplication-Sign 10{sup -5} cm{sup 2}V{sup -1}, respectively. The value of {mu}{tau} is in the range (4-9) Multiplication-Sign 10{sup -5} cm{sup 2}V{sup -1} for crystals doped with a divalent cation.

Gazizov, I. M., E-mail: gazizov@isotop.dubna.ru [Institute for Physico-Technical Problems (Russian Federation); Zaletin, V. M. [Dubna University (Russian Federation); Kukushkin, V. M.; Khrunov, V. S. [Institute for Physico-Technical Problems (Russian Federation)

2011-05-15

290

Search for Dimuon Decays of a Light Scalar Boson in Radiative Transitions Y -> gamma A^0  

SciTech Connect

We search for evidence of a light scalar boson in the radiative decays of the {Upsilon}(2S) and {Upsilon}(3S) resonances: {Upsilon}(2S, 3S) {yields} {gamma}A{sup 0}, A{sup 0} {yields} {mu}{sup +}{mu}{sup -}. Such a particle appears in extensions of the Standaard Model, where a light CP-odd Higgs boson naturally couples strongly to b-quarks. We find no evidence for such processes in the mass range 0.212 {<=} m{sub A{sup 0}} {<=} 9.3 GeV in the samples of 99 x 10{sup 6} {Upsilon}(2S) and 122 x 10{sup 6} {Upsilon}(3S) decays collected by the BABAR detector at the PEP-II B-factory and set stringent upper limits on the effective coupling of the b quark to the A{sup 0}. We also limit the dimuon branching fraction of the {eta}{sub b} meson: {Beta}({eta}{sub b} {yields} {mu}{sup +}{mu}{sup -}) < 0.9% at 90% confidence level.

Aubert, B.

2009-06-02

291

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

SciTech Connect

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

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

1989-03-01

292

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

NASA Astrophysics Data System (ADS)

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

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

1989-03-01

293

Search for ultra-high-energy radiation from {gamma}-ray bursts  

SciTech Connect

Using data from the CYGNUS extensive air shower array, we have searched for evidence of emission of ultra-high-energy radiation coincident with {gamma}-ray bursts observed by the BATSE instrument on the Compton Gamma-Ray Observatory. No statistically significant excess was found for any point in the sky within 4{sigma} of BATSE`s best location coordinates for any of the 56 bursts examined. Furthermore, no events were seen in the 2.2{degree} radius circular bin surrounding {gamma}-ray burst GRB 920720, whose location was determined accurately by the Compton/Ulysses/PVO Interplanetary Network of satellites. Flux upper limits depend greatly on the actual zenith angle of the burst. Typical fluence upper limits above 100 TeV are {approximately}10{sup {minus}6} erg cm{sup {minus}2}. The fluence upper limits for GRB 920720 is 2 {times} 10{sup {minus}6} erg cm{sup {minus}2}.

Schnee, R.W.; The CYGNUS Collaboration

1993-05-01

294

Search for ultra-high-energy radiation from [gamma]-ray bursts  

SciTech Connect

Using data from the CYGNUS extensive air shower array, we have searched for evidence of emission of ultra-high-energy radiation coincident with [gamma]-ray bursts observed by the BATSE instrument on the Compton Gamma-Ray Observatory. No statistically significant excess was found for any point in the sky within 4[sigma] of BATSE's best location coordinates for any of the 56 bursts examined. Furthermore, no events were seen in the 2.2[degree] radius circular bin surrounding [gamma]-ray burst GRB 920720, whose location was determined accurately by the Compton/Ulysses/PVO Interplanetary Network of satellites. Flux upper limits depend greatly on the actual zenith angle of the burst. Typical fluence upper limits above 100 TeV are [approximately]10[sup [minus]6] erg cm[sup [minus]2]. The fluence upper limits for GRB 920720 is 2 [times] 10[sup [minus]6] erg cm[sup [minus]2].

Schnee, R.W.

1993-01-01

295

Search for Ultra-High-Energy Radiation from gamma -ray Bursts  

NASA Astrophysics Data System (ADS)

Using data from the CYGNUS extensive air shower array, we have searched for evidence of emission of ultra-high-energy radiation coincident with gamma -ray bursts observed by the BATSE instrument on the Compton Gamma-Ray Observatory. No statistically significant excess was found for any point in the sky within 4sigma of BATSE's best location coordinates for any of the 56 bursts examined. Furthermore, no events were seen in the 1.5(deg) radius circular bin surrounding gamma -ray burst GRB 920720, whose location was determined accurately by the Compton/Ulysses/PVO Interplanetary Network of satellites. Flux upper limits depend greatly on the actual zenith angle of the burst. Typical fluence upper limits above 100 TeV are ~ 10(-6) erg cm(-2) . The fluence upper limit for GRB 920720 is 2 times 10(-6) erg cm(-2) .

Williams, D. A.; Cavalli-Sforza, M.; Coyne, D.; Dorfan, D.; Kelley, L.; Klein, S.; Schnee, R.; Yang, T.; Biller, S.; Chumney, P.; Harmon, M.; Shoup, A.; Yodh, G. B.; Alexandreas, D. E.; Allen, G. E.; Chang, C. Y.; Chen, M. L.; Dion, C.; Goodman, J. A.; Haines, T. J.; Stark, M. J.; Dion, G. M.; Berley, D.; Burman, R. L.; Hoffman, C. M.; Nagle, D. E.; Schmidt, D. M.; Sinnis, C.; Weeks, D. D.; Zhang, W. P.; Ellsworth, R. W.; Wu, J.-P.

1993-05-01

296

Gamma radiation effects on phenolics, antioxidants activity and in vitro digestion of pistachio (Pistachia vera) hull  

NASA Astrophysics Data System (ADS)

The effect of gamma radiation (10, 20, 30, 40, 50 and 60 kGy) on tannin, total phenolics, antioxidants activity and in vitro digestion of pistachio hulls has been investigated in this study. The possibility of using the radial diffusion method based on software measurement of the rings area has also been investigated in this study. The software based method in radial diffusion method showed a higher r2 (0.995) value when compared to the traditional method. Irradiation reduced the tannin content (P<0.01) and activity of antioxidants (P<0.05) of pistachio hull extracts but increased the total phenolic content (P<0.05). There was no effect of gamma irradiation on the in vitro digestion of the pistachio hull. Irradiation decreased the digestion rate of the pistachio hull at the dose of 40 kGy when compared to the control. This study showed that gamma irradiation decreased tannin and antioxidants activity of pistachio hull.

Behgar, M.; Ghasemi, S.; Naserian, A.; Borzoie, A.; Fatollahi, H.

2011-09-01

297

Performance of neutron and gamma personnel dosimetry in mixed radiation fields  

SciTech Connect

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.

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

1981-01-01

298

Factors affecting the gamma response of TLD-700 chips in mixed-radiation fields  

SciTech Connect

To determine the causes of gamma dose equivalent overestimates observed during mixed-radiation field personnel dosimetry intercomparisons at Oak Ridge National Laboratory, a study was performed to evaluate the effects of phosphor neutron sensitivity, badge materials, and phantoms on the response of TLD-700 chips. The results of the study presented in this paper indicate that even if a phosphor with relatively low neutron sensitivity is used, significant gamma overestimates can occur in mixed fields due to the interaction of the phosphor and badge materials with neutrons. Low energy photons can also contribute to gamma dose equivalent overestimates due to the increased sensitivity of the TLD-700 phosphor to photons with energies below about 100 keV.

Swaja, R.E. (Health and Safety Research Div., Oak Ridge National Lab., Oak Ridge, TN (US)); Scofield, P.A. (Radiological and Occupational Health Dept., Univ. of Michigan, Ann Arbor, MI (US))

1986-10-01

299

Gamma Radiation Induces Micronucleated Reticulocytes in 3-D Bone Marrow Bioreactors in Vitro  

PubMed Central

Radiation injury to the bone marrow is potentially lethal due to the potent DNA-damaging effects on cells of the hematopoietic system, including bone marrow stem cell, progenitor, and the precursor cell populations. Investigation of radiation genotoxic effects on bone marrow progenitor/precursor cells has been challenged by the lack of optimal in vitro surrogate organ culture systems, and the overall difficulty to sustain lineage-specific proliferation and differentiation of hematopoiesis in vitro. We report the investigation of radiation genotoxic effects in bone marrow cultures of C57Bl/6 mice established in 3-D bioreactors, which sustain long-term bone marrow cultures. For these studies, genotoxicity is measured by the induction of micronucleated reticulocytes (MN-RET). The kinetics and dose-response relationship of MN-RET induction in response to gamma-radiation of bioreactor-maintained bone marrow cultures are presented. Our data showed that 3-D long-term bone marrow cultures had sustained erythropoiesis capable of generating reticulocytes up to 8 weeks. The peak time-interval of viable cell output and percentage of reticulocytes increased steadily and reached the initial peak between the 14th to 21st days after inoculations. This was followed by a rebound or staying relatively constant until week 8. The percentage of MN-RET reached the maximum between 24 and 32 hours post 1 Gy gamma-ray. There was a near linear MN-RET induction by gamma radiation from 0 Gy to 1.0 Gy, followed by an attenuated increase to 1.5 2.0 Gy. The MN-RET response showed a downtrend beyond 2 Gy. Our data suggest that bone marrow culture in the 3-D bioreactor may be a useful organ culture system for the investigation of radiation genotoxic effect in vitro.

Sun, Hongliang; Dertinger, Stephen D.; Hyrien, Ollivier; David Wu, J. H.; Chen, Yuhchyau

2009-01-01

300

Quercetin ameliorates gamma radiation-induced DNA damage and biochemical changes in human peripheral blood lymphocytes.  

PubMed

We investigated the radioprotective efficacy of quercetin (QN), a naturally occurring flavonoid against gamma radiation-induced damage in human peripheral blood lymphocytes and plasmid DNA. In plasmid study, QN at different concentrations (3, 6, 12, 24 and 48 microM) were pre-incubated with plasmid DNA for 1h followed by exposure of 6 Gy radiation. Among all concentrations of QN used, 24 microM showed optimum radioprotective potential. To establish the most effective protective concentration of QN in lymphocytes, the cells were pre-incubated with 3, 6, 12, 24 and 48 microM of QN for 30 min and then exposed to 4 Gy gamma-radiation. The concentration-dependent effects of QN were evaluated by scoring micronuclei (MN) frequencies. The results showed that QN decreased the MN frequencies dose dependently, but the effect was more pronounced at 24 microM. Thus, 24 microM of QN was selected as the optimum concentration and was further used to evaluate its radioprotective effect in lymphocytes. For that a separate experiment was carried out, in which lymphocytes were incubated with QN (24 microM) for 30 min and exposed to different doses of radiation (1, 2, 3 and 4 Gy). Genetic damage (MN, dicentric aberration and comet attributes) and biochemical changes were measured to evaluate the effect of QN on gamma-radiations (1-4 Gy). Radiation exposed showed significant increases in the genetic damage and thiobarbituric acid reactive substances (TBARS) accompanied by a significant decrease in the antioxidant status. QN pretreatment significantly decreased the genetic damage and TBARS and improved antioxidant status through its antioxidant potential. Altogether, our findings encourage further mechanistic and in vivo studies to investigate radioprotective efficacy of QN. PMID:18436471

Devipriya, Nagarajan; Sudheer, Adluri Ram; Srinivasan, Marimuthu; Menon, Venugopal P

2008-03-15

301

Somatic aberration induction in Tradescantia occidentalis by neutrons, x- and gamma-radiations. I. Dosimetry.  

PubMed

The dosimetry is described for an investigation of the induction of somatic aberrations in Tradescantia occidentalis by substantially mono-energetic neutrons in the energy range 100 keV to 15 MeV, by 200 keV X-rays and cobalt-60 gamma-radiation. Spectrometry was carried out for both neutrons and X-rays. Neutron fluence was measured by uranium fission chambers. Two types of ionization chamber were employed for dose measurement. One chamber was manufactured of CH-plastic and filled with acetylene and the other of graphite and filled with carbon dioxide. Dosimetry for X- and gamma-radiation was by means of lithium fluoride thermoluminescent dosemeters calibrated against a Victoreen ionization chamber. PMID:1084865

Dennis, J A; Delafield, H J; Peaple, L H; Boot, S J

1976-04-01

302

Three-dimensional radiation dosimetry for gamma knife using a gel dosimeter  

NASA Astrophysics Data System (ADS)

The use of three-dimensional radiation dosimetry has been limited. With the use of water phantoms and ionization chambers, it has been possible to determine three dimensional dose distributions on a gross scale for cobalt 60 and linear accelerator sources. This method has been somewhat useful for traditional radiotherapy. There is, however, a need for more precise dosimetry, particularly with stereotactic radiosurgery. Most gamma knife facilities use either thermoluminescant dosimetry or film, neither of which provides three dimensional dose distributions. To overcome this limitation, we have developed a gel dosimetry system that relies on the production of a ferric ion-xylenol orange colored complex. This work demonstrates the use of laser light and a detector to quantify radiation-induced colorimetric changes in absorbance for the gel dosimeter. The absorbance has been reconstructed by the back projection technique to demonstrate the applicability of the gel dosimeter to gamma knife 3D-dose distributions.

Hussain, Kazi Muazzam

303

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

304

Development and characterization of starch nanoparticles by gamma radiation: potential application as starch matrix filler.  

PubMed

Gamma radiation arises as an advantageous alternative to obtain starch nanoparticles given its low cost, simple methodology and scalability. Starch nanoparticles (SNP) with sizes around 20 and 30 nm were obtained applying a dose of 20 kGy from cassava (CNP-?) and waxy maize (WNP-?) starch, respectively. They showed the same thermal degradation behavior and their maximum mass loss zone was similar to those nanoparticles obtained from acid hydrolysis (WNP-h). Additionally, CNP-? and WNP-? were used as nanofillers in a cassava matrix. Increments of 102% in storage modulus were obtained with the addition of only 2.5 wt.% of WNP-?, showing that gamma radiation is a successful methodology to obtain SNP able to be used as starch reinforcement. PMID:23769521

Lamanna, Melisa; Morales, No J; Garca, Nancy Lis; Goyanes, Silvia

2013-05-03

305

Gamma radiation effects on erbium-doped fiber in superfluorescent fiber source  

NASA Astrophysics Data System (ADS)

The radiation effects of two erbium-doped superfluorescent fiber sources (SFSs) are studied in gamma ray environment. Two types of output spectrum profile (twin-peaked spectrum and single-peaked spectrum) of SFSs are constructed by different configuration and parameters. The dependence of radiation-induced power loss and spectra evolution on the dosage is revealed. The results show that the amplitudes of radiation-induced power decrease are quite similar in two SFSs. But the mean wavelength variation of the single-peaked spectrum SFS is approximately 25 times smaller than that of the twin-peaked spectrum SFS. Compared to the twin-peaked spectrum SFS, the single-peaked spectrum SFS presents better radiation tolerance, which should have potential advantages in space applications.

Liu, Chengxiang; Zhang, Li; Wu, Xu; Ruan, Shuangchen

2013-10-01

306

Health Effects of Low-Level Ionizing Radiation.  

National Technical Information Service (NTIS)

It is now assumed that any exposure to radiation at low levels of dose carries some risk of deleterious effects. How low this level may be, or the probability or magnitude of the risk, still are not known. Our best scientific knowledge and advice are esse...

J. I. Fabrikant

1979-01-01

307

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

SciTech Connect

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

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

2003-12-01

308

Gamma-radiation-induced wood-plastic composites from Syrian tree species  

NASA Astrophysics Data System (ADS)

Wood-plastic composites (WPC) have been prepared with five low-grade woods, native to Syria, using three monomer systems; acrylamide, butylmethacrylate, and styrene, with methanol as the swelling solvent. Polymerization was induced at various radiation doses (10, 20, and 30kGy) at a dose rate of 3.5kGy/h using a 60Co gamma radiation source. Some physical properties of WPC, namely polymer loading and compression strength have been measured. The polymer loading decreases approximately with increasing density of the wood species used.

Bakraji, E. H.; Salman, N.; Al-kassiri, H.

2001-05-01

309

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

DOEpatents

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

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

1997-01-01

310

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

DOEpatents

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

Condreva, K.J.

1997-01-14

311

Comparison of proton microbeam and gamma irradiation for the radiation hardness testing of silicon PIN diodes  

NASA Astrophysics Data System (ADS)

Simple and cost-effective solutions using Si PIN diodes as detectors are presently utilized in various radiation-related applications in which excessive exposure to radiation degrades their charge transport properties. One of the conventional methods for the radiation hardness testing of such devices is time-consuming irradiation with electron beam or gamma-ray irradiation facilities, high-energy proton accelerators, or with neutrons from research reactors. Recently, for the purpose of radiation hardness testing, a much faster nuclear microprobe based approach utilizing proton irradiation has been developed. To compare the two different irradiation techniques, silicon PIN diodes have been irradiated with a Co-60 gamma radiation source and with a 6 MeV proton microbeam. The signal degradation in the silicon PIN diodes for both irradiation conditions has been probed by the IBIC (ion beam induced charge) technique, which can precisely monitor changes in charge collection efficiency. The results presented are reviewed on the basis of displacement damage calculations and NIEL (non-ionizing energy loss) concept.

Jaki?, M.; Grilj, V.; Skukan, N.; Majer, M.; Jung, H. K.; Kim, J. Y.; Lee, N. H.

2013-09-01

312

Effect of gamma radiation on membrane fluidity of MOLT-4 nuclei  

SciTech Connect

These experiments measured the effect of gamma radiation on the nuclear envelope using doxyl-fatty acid spin-label probes. Nuclei were isolated from cultured MOLT-4 cells, a radiation-sensitive human T-cell lymphocyte. Membrane fluidity was measured from the electron paramagnetic resonance spectra of the probes. MOLT-4 cells were grown under standard conditions, and suspensions were exposed to 60Co gamma radiation at room temperature. The spectra of 5-doxylstearic acid in the nuclei were those of a strongly immobilized label. A difference in the membrane fluidity was detected in a series of experiments comparing labeled irradiated and nonirradiated nuclei. The change in fluidity was measured by comparing the changes in the order parameter, S, of the spin label in irradiated nuclei with those in control nuclei. The change in the S ratio is dependent on radiation dose, increasing with doses up to 15 Gy. The maximum change of the order parameter with time after irradiation occurs 16-20 h after radiation exposure. These observations are correlated with changes in cell viabilities.

McClain, D.E.; Trypus, C.A.; May, L. (Armed Forces Radiobiology Research Institute, Bethesda, MD (USA))

1990-09-01

313

EFFECT OF Co⁶°$gamma$ RADIATION ON VITAMIN B-GROUP SUBSTANCES  

Microsoft Academic Search

When aqueous solutions of 0.030 mg\\/ml pyridoxine hydrochloride, ; pyridoxal hydrochloride, and pyridoxamine dihydrochloride, the pH of which had ; been adjusted to approximates 2 with 0.01N hydrochloric acid, were irradiated ; with Co⁶° gamma radiation at a dose of 10⁵ rep, the loss of the ; vitamin was 94, 77, and 70%, respectively. Losses of less than 10% were

Shiroishi

1961-01-01

314

Circular polarization of gamma-radiation after capture of polarized thermal neutrons  

Microsoft Academic Search

With a Ge(Li) spectrometer, the circular polarization of gamma-radiation due to capture of polarized thermal neutrons in K, Ca, Ti, Co, Cd and Pb was determined from transmission measurements through magnetized iron cobalt alloy. The following unambiguous spin assignments result from these measurements (Ex in keV); J(2290) = 2 in 40K; J(3174) = 1\\/2 in 49Ti; J(785) = 5 in

K. Abrahams; W. Ratynski

1969-01-01

315

Calicivirus Inactivation by Nonionizing (253.7-Nanometer-Wavelength [UV]) and Ionizing (Gamma) Radiation  

Microsoft Academic Search

Noroviruses (previously Norwalk-like viruses) are the most common viral agents associated with food- and waterborne outbreaks of gastroenteritis. In the absence of culture methods for noroviruses, animal calicivi- ruses were used as model viruses to study inactivation by nonionizing (253.7-nm-wavelength (UV)) and ionizing (gamma) radiation. Here, we studied the respiratory feline calicivirus (FeCV) and the presumed enteric canine calicivirus (CaCV)

A. M. de Roda Husman; Paul Bijkerk; Willemijn Lodder; Harold van den Berg; Walter Pribil; Alexander Cabaj; Peter Gehringer; Regina Sommer; Erwin Duizer

2004-01-01

316

Dose quantities and instrumentation for measuring environmental gamma radiation during emergencies  

Microsoft Academic Search

The dosimetry for exposure to gamma radiation in the environment is reviewed, including the factors used to convert measurements of traceable quantities to effective dose equivalent. A value of 0.70 Sv Gy-1 is widely used to convert air kerma or absorbed dose-to-air to effective dose equivalent, but recent work shows that a value of 0.86 Sv Gy-1 is more appropriate

M. J. Clark; P. H. Burgess; D. R. McClure

1993-01-01

317

Observation of the radiative decay J/psi. -->. gamma. eta. pi pi  

SciTech Connect

The radiative decay J/psi ..-->.. ..gamma.. eta ..pi pi.. has been observed in data taken with the Crystal Ball detector at the SPEAR e/sup +/e/sup -/ storage ring. In addition to the well-known eta', the eta ..pi pi.. mass spectrum shows a broad enhancement centered at approx. 1700 MeV. There is no explicit evidence for the l(1440) in the eta ..pi pi.. mass spectrum.

Newman-Holmes, C.

1982-09-01

318

Immobilization of Urease on (HEMA\\/IA) Hydrogel Prepared by Gamma Radiation  

Microsoft Academic Search

In the present study, the copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were synthesized by gamma radiation induced radical polymerization, in order to examine the potential use of these hydrogels in immobilization of Citrullus vulgaris urease. Gelation and Swelling properties of PHEMA and copolymeric P (HEMA\\/IA) hydrogels with different IA contents (96.5\\/3.5, 94.4\\/5.6 and 92.5\\/7.5 mol)

Soha M. Hamdy; Samia El-Sigeny; Manal F. Abou Taleb

2008-01-01

319

Observation of a gamma-ray flash at ground level in association with a cloud-to-ground lightning return stroke  

NASA Astrophysics Data System (ADS)

Terrestrial gamma-ray flashes (TGFs) are bright, sub-millisecond bursts of gamma-rays, originating within the Earth's atmosphere. Most TGFs have been detected by spacecraft in low-Earth orbit. Only two TGFs have previously been observed from within our atmosphere: one at ground level and one from an aircraft at 14.1 km. We report on a new TGF-like gamma-ray flash observed at ground level, detected by the 19-station Thunderstorm Energetic Radiation Array (TERA) at the University of Florida/Florida Tech International Center for Lightning Research and Testing (ICLRT). The gamma-ray flash, which had a duration of 52.7 ?s, occurred on June 30, 2009 during a natural negative cloud-to-ground lightning return stroke, 191 ?s after the start of the stroke. This event is the first definitive association of a gamma-ray flash with natural CG lightning and is among the most direct links to a specific lightning process so far. For this event, 19 gamma-rays were recorded, with the highest energy exceeding 20 MeV. The high-energy radiation exhibited very different behavior from the typical x-ray emission from lightning. Specifically, the gamma-ray flash had a much harder energy spectrum, consistent with relativistic runaway electron avalanche (RREA) multiplication; it did not arrive in sub-microsecond bursts, typical of leader emission from lightning, and it occurred well after the start of the return stroke, which has not been previously observed for the x-ray emission from lightning. Nevertheless, we present evidence that the source region for the gamma ray flash was the same as that for the preceding leader x-ray bursts.

Dwyer, J. R.; Schaal, M. M.; Cramer, E.; Arabshahi, S.; Liu, N.; Rassoul, H. K.; Hill, J. D.; Jordan, D. M.; Uman, M. A.

2012-10-01

320

Ground level radiation from cosmic ray shower secondaries  

NASA Astrophysics Data System (ADS)

Most cosmic ray secondaries never reach ground level, however high energy cosmic rays produce muons and neutrons which do. These particles are known to cause increased radiation and cancer rates under current day cosmic ray flux. Episodic increases in the high energy cosmic ray flux increase this radiation, and thus the risk to biological life. Our work models the flux of neutrons and muons produced by high energy cosmic rays, exploring the possibility of biological impact due to extended periods of increase high energy cosmic ray muon flux. Our results find secondary muon radiation to be significant in cosmic ray flux increasing events.

Overholt, Andrew

2013-04-01

321

Interaction of gamma Radiation and Temperature on the Determination of the Sterilizing Dose of Some Stored Products Pests.  

National Technical Information Service (NTIS)

The influence of temperature on sterilizing dosages of gamma radiation was studied for Sitophilus zeamais Mots. in corn, Sitophilus oryzae (L.) in rice, Araecerus fasciculatus (DeGeer) in coffee, and Zabrotes subfasciatus (Boh.) in beans. It was found tha...

A. P. Barbosa

1976-01-01

322

Results of calculations of external gamma radiation exposure rates from fallout and related radionuclide compositions. Operation Teapot, 1955  

SciTech Connect

This report presents data on calculated gamma radiation exposure rates and ground deposition of related radionuclides resulting from events that deposited detectable radioactivity outside the Nevada Test Site complex.

Hicks, H.G.

1981-07-01

323

Incidence of fruit flies on coffee and citrus and quarantine treatment of citrus fruits by gamma radiation.  

National Technical Information Service (NTIS)

The objective of this study was to evaluate the fruit fly infestation on coffee and citrus, and also to determine gamma radiation doses for immature stages of Ceratitis capitata and Anastrepha fraterculus, in order to satisfy quarantine regulations. Coffe...

A. Raga

1996-01-01

324

Enhancement of natural background gamma-radiation dose around uranium microparticles in the human body.  

PubMed

Ongoing controversy surrounds the adverse health effects of the use of depleted uranium (DU) munitions. The biological effects of gamma-radiation arise from the direct or indirect interaction between secondary electrons and the DNA of living cells. The probability of the absorption of X-rays and gamma-rays with energies below about 200 keV by particles of high atomic number is proportional to the third to fourth power of the atomic number. In such a case, the more heavily ionizing low-energy recoil electrons are preferentially produced; these cause dose enhancement in the immediate vicinity of the particles. It has been claimed that upon exposure to naturally occurring background gamma-radiation, particles of DU in the human body would produce dose enhancement by a factor of 500-1000, thereby contributing a significant radiation dose in addition to the dose received from the inherent radioactivity of the DU. In this study, we used the Monte Carlo code EGSnrc to accurately estimate the likely maximum dose enhancement arising from the presence of micrometre-sized uranium particles in the body. We found that although the dose enhancement is significant, of the order of 1-10, it is considerably smaller than that suggested previously. PMID:19776147

Pattison, John E; Hugtenburg, Richard P; Green, Stuart

2009-09-23

325

Enhancement of natural background gamma-radiation dose around uranium microparticles in the human body  

PubMed Central

Ongoing controversy surrounds the adverse health effects of the use of depleted uranium (DU) munitions. The biological effects of gamma-radiation arise from the direct or indirect interaction between secondary electrons and the DNA of living cells. The probability of the absorption of X-rays and gamma-rays with energies below about 200 keV by particles of high atomic number is proportional to the third to fourth power of the atomic number. In such a case, the more heavily ionizing low-energy recoil electrons are preferentially produced; these cause dose enhancement in the immediate vicinity of the particles. It has been claimed that upon exposure to naturally occurring background gamma-radiation, particles of DU in the human body would produce dose enhancement by a factor of 5001000, thereby contributing a significant radiation dose in addition to the dose received from the inherent radioactivity of the DU. In this study, we used the Monte Carlo code EGSnrc to accurately estimate the likely maximum dose enhancement arising from the presence of micrometre-sized uranium particles in the body. We found that although the dose enhancement is significant, of the order of 110, it is considerably smaller than that suggested previously.

Pattison, John E.; Hugtenburg, Richard P.; Green, Stuart

2010-01-01

326

[Mechanism of injury of air-dry pea seeds under the influence of low doses of gamma-radiation].  

PubMed

The aim of this work was to determine which processes in air-dry seeds result in bimodal changes of the pea seed quality under the influence of low doses of gamma-radiation. Pea seeds (cv. "Nemchinovsky-85", harvest 2006, 82% germination persentage) were exposed to gamma-radiation at doses of 3, 10 and 100 Gy The germination percentage decreased to 45% four days after irradiation at the dose of 3 Gy, rised up to 87% at doses of 10 Gy, while the dose of 100 Gy killed the most part of seeds. Seed fractions differing in quality were selected using the metod of Room temperature phosphorecsence (RTP): strong seed frasction I from non-irradiated seeds; weak seed fraction II from the seeds irradiated at a dose of 3 Gy; dead seeds from the seeds irradiated at a dose of 100 Gy. ThermoChemiLuminecnsece (TCL) of seed powders and cotyledons was used. It was shown that the increase of the TCL level in the temperature range from 50 to 110 degreesC was associated with the lipid peroxidation products. The TCL level of seeds subjected to gamma-irradiation at a dose of 3 Gy was similar to that of non-irradiated seeds in the temperature range 50 to 100 degreesC. Therefore, lipid peroxidation was not the cause of the abnormal seedling appearance. The TCL level within this temperature range was increased only in seeds subjected to y-irradiation at a dose of 100 Gy. The TCL level at 150 degreesC was in proportion with the exogenous glucose amount. The increased TCL level of seeds subjected to y-irradiation at a dose of 3 Gy at 150 degreesC resulted from the increase of the glucose content. This means that the transition from the fraction of strong seeds into the fraction of weak ones was the result of the activation of hydrolysis processes. Decrease in the water content of seeds testified to utilization of bound water in this process. The decrease of the glucose content in the "improved" seeds subjected to gamma-irradiation at a dose of 10 Gy most probably indicates the participation of glucose in the amino carbonyl reaction. The latter could be the reason for the increased water content in the "improved" seeds and a decreased water permeability of cell membranes. PMID:22568014

Veselova, T V; Veselovski?, V A

327

Is Exposure to Low Radiation Levels Good For You?  

NASA Astrophysics Data System (ADS)

Little is known about the biological effects of very low levels of ionizing radiation. We propose an experiment to compare cell response to such low radiation levels, using fast replicating yeast cells. Saccharomyces Cerevisae (SC), a type of yeast, is an eukariotic unicellular microorganism with a mean cell generation time of 90 min. Its genetic organization is similar to that of superior organisms, but at the same time is very easy to handle, with special reference to its genetic analysis. Certain CS strains are widely employed for mutagenesis studies. We propose to expose simultaneously three indentical CS cultures for a period of up to a few weeks (100s of cell generations): to natural backgroung (NB) ionizing radiation (at a ground level lab), to sub-NB level (underground) and to supra-NB level (at a high altitude). At the end of the exposure we will chemically challenge the cultured cells with methyl-methane-sulphonate (MMS), a standard chemical mutagen. Mitotic recombination frequency in the MMS exposed cultures is an index of early DNA damage induction at high survival levels (ie at very low radiation levels). This experiment can be handsomely and inexpensively accomodated in one of the existing underground laboratories.

Dimitroyannis, Dimitri

1996-05-01

328

Branching fractions and CP-violating asymmetries in radiative B decays to {eta}K{gamma}  

SciTech Connect

We present measurements of the CP-violation parameters S and C for the radiative decay B{sup 0}{yields}{eta}K{sub S}{sup 0}{gamma}; for B{yields}{eta}K{gamma} we also measure the branching fractions and for B{sup +}{yields}{eta}K{sup +}{gamma} the time-integrated charge asymmetry A{sub ch}. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 465x10{sup 6} BB pairs produced in e{sup +}e{sup -} annihilation. The results are S=-0.18{sub -0.46}{sup +0.49}{+-}0.12, C=-0.32{sub -0.39}{sup +0.40}{+-}0.07, B(B{sup 0}{yields}{eta}K{sup 0}{gamma})=(7.1{sub -2.0}{sup +2.1}{+-}0.4)x10{sup -6}, B(B{sup +}{yields}{eta}K{sup +}{gamma})=(7.7{+-}1.0{+-}0.4)x10{sup -6}, and A{sub ch}=(-9.0{sub -9.8}{sup +10.4}{+-}1.4)x10{sup -2}. The first error quoted is statistical and the second systematic.

Aubert, B.; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E.; Prudent, X.; Tisserand, V. [Laboratoire de Physique des Particules, IN2P3/CNRS et Universite de Savoie, F-74941 Annecy-Le-Vieux (France); Tico, J. Garra; Grauges, E. [Facultat de Fisica, Departament ECM, Universitat de Barcelona, E-08028 Barcelona (Spain); Eigen, G.; Stugu, B.; Sun, L. [University of Bergen, Institute of Physics, N-5007 Bergen (Norway); Abrams, G. S.; Battaglia, M.; Brown, D. N.; Cahn, R. N.; Jacobsen, R. G.; Kerth, L. T.; Kolomensky, Yu. G. [Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA and University of California, Berkeley, California 94720 (United States)] (and others)

2009-01-01

329

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

SciTech Connect

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

Aubert, B.

2008-05-14

330

umuC-dependent and umuC-independent gamma- and UV-radiation mutagenesis in Escherichia coli.  

PubMed

The effects of the umuC36 and umuC122::Tn 5 mutations on gamma- and UV radiation mutagenesis (nonsense, missense, and frameshift mutation assays) in Escherichia coli K12 were studied. Although both mutations reduced radiation mutagenesis, the umuC36 mutation appeared to be leaky since considerably more UV radiation mutagenesis could be detected in the umuC36 strain than in the umuC122::Tn 5 strain. In general, the umuC strain showed much larger deficiencies in UV radiation mutagenesis than they did for gamma-radiation mutagenesis. The mutability of the umuC122:: Tn 5 strain varied depending on the radiation dose, and the mutation assay used. For gamma-radiation mutagenesis, the deficiency varied from no deficiency to a 50-fold deficiency; for UV radiation mutagenesis, the deficiency varied from 100-fold to at least 5000-fold. We concluded that both umuC-dependent and umuC-independent modes function for gamma-radiation mutagenesis, while UV radiation mutagenesis seems to depend almost exclusively on the umuC-dependent mode. PMID:6088973

Sargentini, N J; Smith, K C

1984-08-01

331

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

SciTech Connect

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

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

1983-03-01

332

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

PubMed

After N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis of Escherichia coli K-12 (xthA14), and X-ray-sensitive mutant was isolated. This sensitivity is due to a mutation, radB101, which is located at 56.5 min on the E. coli K-12 linkage map. The radB101 mutation sensitized wildtype cells to gamma and uv radiation, and to methyl methanesulfonate. When known DNA repair-deficient mutants were ranked for their gamma-radiation sensitivity relative to their uv-radiation sensitivity, their order was (starting with the most selectively gamma-radiation-sensitive strain): recB21, radB101, wild type, polA1, recF143, lexA101, recA56, uvrD3, and uvrA6. The radB mutant was normal for gamma- and uv-radiation mutagenesis, it showed only a slight enhancement of gamma- and uv-radiation-induced DNA degradation, and it was approximately 60% deficient in recombination ability. The radB gene is suggested to play a role in the recA gene-dependent (Type III) repair of DNA single-strand breaks after gamma irradiation and in postreplication repair after uv irradiation for the following reasons; the radB strain was normal for the host-cell reactivation of gamma- and uv-irradiated bacteriophage lambda; the radB mutation did not sensitize a recA strain, but did sensitize a polA strain to gamma and uv radiation; the radB mutation sensitized a uvrB strain to uv radiation. PMID:6344125

Sargentini, N J; Smith, K C

1983-03-01

333

Effects of gamma irradiation on the radiation-resistant bacteria and polyphenol oxidase activity in fresh kale juice  

Microsoft Academic Search

Gamma radiation was performed to prolong the shelf life of natural kale juice. The total aerobic bacteria in fresh kale juice, prepared by a general kitchen process, was detected in the range of 106cfu\\/ml, and about 102cfu\\/ml of the bacteria survived in the juice in spite of gamma irradiation treatment with a dose of 5kGy. Two typical radiation-resistant bacteria, Bacillus

Dongho Kim; Hyunpa Song; Sangyong Lim; Hyejeong Yun; Jinwoo Chung

2007-01-01

334

RADIATION SENSITIVITY AND QUALITY OF FRESH-CUT VEGETABLES EXPOSED TO GAMMA RADIATION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Thirteen fresh-cut (minimally processed) vegetables (broccoli, cilantro, red cabbage, endive, parsley, green and red leaf lettuce, Iceberg and Romaine lettuce, spinach, carrots, green onions, and celery) plus alfalfa sprouts were gamma irradiated at doses up to 3 kGy at 0.5 kGy intervals. The sample...

335

Possible low-lying levels in /sup 165/Dy deduced from neutron capture. gamma. rays  

SciTech Connect

The high-energy thermal neutron capture ..gamma.. rays in /sup 165/Dy have been studied. Analysis has revealed 15 new levels below an excitation energy of 1650 keV in addition to 14 that were previously reported. The spins of the newly observed levels are most likely (1/2) or (3/2).

Islam, M.A.; Prestwich, W.V.; Kennett, T.J.

1983-05-01

336

Effects of gamma radiation and temperature on the biological assimilation and retention of 137Cs by Acheta domesticus (L.).  

PubMed

Cesium-137 retention was determined for brown crickets, Acheta domesticus, which had been irradiated with 0, 1000, 2500 and 5000 rad gamma radiation and maintained at 20, 25 and 30 degrees C. Parameters examined for temperature and dose effects were (1) per cent 137Cs assimilated into body tissues (p2), (2) rate of isotope passage through the gut (k1) and (3) rate of elimination of assimilated 137Cs (ks). Increases in temperature and gamma dose resulted in a general decrease in per cent 137Cs assimilated pe day (p2). The first-component elimination coefficient (k1) was not significantly affected (P less than or equal to 0.05) by either temperature or dose changes. Biological elimination coefficients for assimilated 137Cs (k2) increased with increasing temperature between doses of 0 and 2500 rad. Above 2500 rads however, increases in temperature had no noticeable effects on the rate of assimilated 137Cs excretion. At higher dose levels, radiation was the dominant factor influencing the parameter k2. PMID:5212283

Van Hook, R I; Herbert, E T

1971-12-01

337

Interferon-gamma levels in peritoneal dialysis effluents: Relation to peritonitis  

Microsoft Academic Search

Interferon-gamma levels in peritoneal dialysis effluents: Relation to peritonitis. As peritoneal macrophages require Interferon-? (IFN-?) for bacterial lysis, IFN-? levels were measured in peritoneal dialysis effluents (PDE) by a specific radioimmunoassay. High IFN-? levels were found in patients with peritonitis compared to low levels in patients without peritonitis ([xmacr ] 9.73 2.63 SE U\\/ml, N = 39 vs. 0.25

Mrinal K Dasgupta; Marlene Larabie; Philip F Halloran

1994-01-01

338

Size effects on gamma radiation response of magnetic properties of barium hexaferrite powders  

SciTech Connect

Little is currently known about the effects of gamma-ray irradiation on oxide magnet materials. In particular, the effect of particle size on radiation susceptibility was investigated. Two commercial powders of BaFe{sub 12}O{sub 19} were thoroughly characterized, then exposed to 1 MGy of gamma radiation from a {sup 60}Co source. AC susceptibility and DC magnetometry and Moessbauer spectroscopy were performed after irradiation and compared to pre-irradiated measurements. DC magnetization and AC susceptibility decreased for both samples with the relative change of DC magnetization being larger for the micrometer-sized particles and the relative change of the AC susceptibility being larger for the nanometer-sized particles. Moessbauer spectroscopy indicated a decrease in both the hyperfine fields and in their distribution for each Fe site, particularly in the larger particle sample. Decreases in susceptibility are believed to be due to radiation-induced amorphization at the particle surfaces as well as amorphization and nucleation of new crystallites at internal crystallite boundaries, resulting in overall reduction in the particle magnetic moment. This radiation damage mechanism is different than that seen in previous studies of neutron and heavy ion irradiation of BaFe{sub 12}O{sub 19}.

McCloy, John; Kukkadapu, Ravi; Crum, Jarrod; Johnson, Brad; Droubay, Tim [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

2011-12-01

339

Disinfection of domestic effluents by gamma radiation: effects on the inactivation of Ascaris lumbricoides eggs.  

PubMed

This work investigated the inactivation of Ascaris lumbricoides eggs in domestic effluents by gamma radiation from a (60)Co source. Domestic wastewater was treated in a compact demo-scale system consisting of a UASB reactor and a trickling filter; treatment was carried out at the Center for Research and Training on Sanitation (CePTS), Federal University of Minas Gerais, in Belo Horizonte-MG, Brazil. One-liter of treated wastewater samples was artificially contaminated with an average of 1000 non-embryonated Ascaris lumbricoides eggs from human feces; samples were then irradiated in a multiple-purpose irradiator at different doses (0.5-5 kGy). Eggs were recovered from the wastewater and the viability of these irradiated eggs was evaluated; the description of the egg developmental phases with each dose of gamma radiation was recorded. Radiation doses of 3.5 kGy effectively disinfected effluents with lower concentrations of A. lumbricoides eggs; higher radiation doses of 5 kGy were necessary to disinfect effluents with higher eggs concentrations. PMID:21911240

de Souza, Gloria S M B; Rodrigues, Ludmila A; de Oliveira, Warllem J; Chernicharo, Carlos A L; Guimares, Marcos P; Massara, Cristiano L; Grossi, Pablo A

2011-08-23

340

Proteomic analysis of global changes in protein expression during exposure of gamma radiation in Bacillus sp. HKG 112 isolated from saline soil.  

PubMed

A Gram-positive bacterium was isolated from the saline soils of Jangpura (U.P.), India, and showed high-level of radiation-resistant property and survived upto 12.5 kGy dose of gamma radiation. The 16S rDNA sequence of this strain was examined, identified as Bacillus sp. strain HKG 112, and was submitted to the NCBI GenBank (Accession No. GQ925432). The mechanism of radiation resistance and gene level expression were examined by proteomic analysis of whole-cell extract. Two proteins, 38 kDa and 86.5 kDa excised from SDS-PAGE, which showed more significant changes after radiation exposure, were identified by MALDI-TOF as being flagellin and S-layer protein, respectively. Twenty selected 2-DE protein spots from the crude extracts of Bacillus sp. HKG 112, excised from 2- DE, were identified by liquid chromatography mass spectrometry (LC-MS) out of which 16 spots showed significant changes after radiation exposure and might be responsible for the radiation resistance property. Our results suggest that the different responses of some genes under radiation for the expression of radiation-dependent proteins could contribute to a physiological advantage and would be a significant initial step towards a full-system understanding of the radiation stress protection mechanisms of bacteria in different environments. PMID:21715963

Gupta, Anil Kumar; Pathak, Rajiv; Singh, Bharat; Gautam, Hemlata; Kumar, Ram; Kumar, Raj; Arora, Rajesh; Gautam, Hemant

2011-06-01

341

Low-level internal radionuclide contamination: use of gamma camera for detection  

SciTech Connect

The uncollimated gamma camera was evaluated as a screening tool for the detection of low levels of internal radionuclide contamination. The minimum detectable activity (MDA) is on the order of 1-4 nCi (37-148 Bq) for a 3-min sample and background counting time. Identification of unknown radionuclides at these low levels involves a systematic search and hence requires a more careful peaking method than organ imaging. Most gamma cameras are capable both of detecting a wide range (35 keV to 1.332 MeV) of gamma-ray energies in the presence of three to four radionuclides and also of distinguishing principal gamma-ray energies from Compton scatter. The differences in MDAs among gamma cameras are small, and vary primarily with the background activity. The actual contaminant activities lie between the calculated values based on measurements when the source is 10 cm away from the uncollimated detector head and using point sources both in air and with the tissue-equivalent scatter medium. The widely available gamma camera is capable of screening a large population, either suspected or actually contaminated, in the event of an emergency.

Nishiyama, H.; Lukes, S.J.; Saenger, E.L.

1984-01-01

342

Low-level internal radionuclide contamination: use of gamma camera for detection  

SciTech Connect

The uncollimated gamma camera was evaluated as a screening tool for the detection of low levels of internal radionuclide contamination. The minimum detectable activity (MDA) is on the order of I-4 nCi (37-148 Bq) for a 3-min sample and background counting time. Identification of unknown radionuclides at these low levels involves a systematic search and hence requires a more careful peaking method than organ imaging. Most gamma cameras are capable both of detecting a wide range (35 keV to 1.332 MeV) of gamma-ray energies in the presence of three to four radionuclides and also of distinguishing principal gamma-ray energies from compton scatter. The differences in MDAs among gamma cameras are small, and vary primarily with the background activity. The actual contaminant activities lie between the calculated values based on measurements when the source is 10 cm away from the uncollimated detector head and using point sources both in air and with the tissue-equivalent scatter medium. The widely available gamma camera is capable of screening a large population, either suspected or actually contaminated, in the event of an emergency.

Nishiyama, H.; Ldes, S.J.; Saenger, E.L.

1984-01-01

343

Effect of gamma radiation on enzymatic activity and sulphydryl groups of human erythrocyte membrane.  

PubMed

The effect of ionizing radiation on human erythrocyte ghost membranes was studied by following changes in membrane -SH groups and activities of four membrane bound enzymes: Na+K+Mg2+ ATP-ase, Mg2+Ca2+ ATP-ase, Na+K+ATP-ase, and AChE. Irradiation up to 100 Gy gamma X-rays produced a significant decrease in the activity of ATP-ase and an increase in AChE activity. At higher radiation doses a marked decrease in the activities of all the enzymes was observed. A correlation between radiation-induced perturbations in enzyme activities and changes in membrane -SH groups was found. PMID:6137463

Pa?ecz, D; Leyko, W

1983-09-01

344

GAMMA-RAY BURST PROMPT EMISSION: JITTER RADIATION IN STOCHASTIC MAGNETIC FIELD REVISITED  

SciTech Connect

We revisit the radiation mechanism of relativistic electrons in the stochastic magnetic field and apply it to the high-energy emissions of gamma-ray bursts (GRBs). We confirm that jitter radiation is a possible explanation for GRB prompt emission in the condition of a large electron deflection angle. In the turbulent scenario, the radiative spectral property of GRB prompt emission is decided by the kinetic energy spectrum of turbulence. The intensity of the random and small-scale magnetic field is determined by the viscous scale of the turbulent eddy. The microphysical parameters {epsilon}{sub e} and {epsilon}{sub B} can be obtained. The acceleration and cooling timescales are estimated as well. Due to particle acceleration in magnetized filamentary turbulence, the maximum energy released from the relativistic electrons can reach a value of about 10{sup 14} eV. The GeV GRBs are possible sources of high-energy cosmic-ray.

Mao, Jirong [International Center for Astrophysics, Korea Astronomy and Space Science Institute, 776, Daedeokdae-ro, Yuseong-gu, Daejeon 305-348 (Korea, Republic of); Wang Jiancheng, E-mail: jirong.mao@brera.inaf.it [Yunnan Observatory, Chinese Academy of Sciences, Kunming, Yunnan Province 650011 (China)

2011-04-10

345

Gamma-ray Burst Prompt Emission: Jitter Radiation in Stochastic Magnetic Field Revisited  

NASA Astrophysics Data System (ADS)

We revisit the radiation mechanism of relativistic electrons in the stochastic magnetic field and apply it to the high-energy emissions of gamma-ray bursts (GRBs). We confirm that jitter radiation is a possible explanation for GRB prompt emission in the condition of a large electron deflection angle. In the turbulent scenario, the radiative spectral property of GRB prompt emission is decided by the kinetic energy spectrum of turbulence. The intensity of the random and small-scale magnetic field is determined by the viscous scale of the turbulent eddy. The microphysical parameters epsilon e and epsilon B can be obtained. The acceleration and cooling timescales are estimated as well. Due to particle acceleration in magnetized filamentary turbulence, the maximum energy released from the relativistic electrons can reach a value of about 1014 eV. The GeV GRBs are possible sources of high-energy cosmic-ray.

Mao, Jirong; Wang, Jiancheng

2011-04-01

346

Effect of gamma radiation on membrane fluidity of MOLT-4 nuclei  

SciTech Connect

These experiments measured the effect of gamma radiation on the nuclear envelope using doxyl-fatty acid spin-label probes. Nuclei were isolated from cultured MOLT-4 cells, a radiation-sensitive human T-cell lymphocyte. Membrane fluidity was measured from the electron paramagnetic resonance spectra of the probes. MOLT-4 cells were grown under standard conditions, and suspension were exposed to CO radiation at room temperature. The spectra of 5-doxylstearic acid in the nuclei were those of a strongly immobilized label. A difference in the membrane fluidity was detected in a series of experiments comparing labeled irradiated and nonirradiated nuclei. The change in fluidity was measured by comparing the changes in the order parameter, S, of the spin label in irradiated nuclei with those in control nuclei.

McClain, D.E.; Trypus, C.A.; May, L.

1990-01-01

347

DNA damage caused by chronic transgenerational exposure to low dose gamma radiation in Medaka fish ( Oryzias latipes ).  

PubMed

The effect of transgenerational exposure to low dose rate (2.4 and 21 mGy/day) gamma irradiation on the yield of DNA double-strand breaks and oxidized guanine (8-hydroxyguanine) has been studied in the muscle and liver tissue of a model organism, the Japanese medaka fish. We found the level of unrepaired 8-hydroxyguanine in muscle tissue increased nonlinearly over four generations and the pattern of this change depended on the radiation dose rate, suggesting that our treatment protocols initiated genomic instability and an adaptive response as the generations progressed. The yield of unrepaired double-strand breaks did not vary significantly among successive generations in muscle tissue in contrast to liver tissue in which it varied in a nonlinear manner. The 8-hydroxyguanine and DSB radiation yields were significantly higher at 2.4 mGy/day than at 21 mGy/day in both muscle and liver tissue in all generations. These data are consistent with the hypothesis of a threshold for radiation-induced activation of DNA repair systems below which tissue levels of DNA repair enzymes remain unchanged, leading to the accumulation of unrepaired damage at very low doses and dose rates. PMID:23919310

Grygoryev, D; Moskalenko, O; Hinton, T G; Zimbrick, J D

2013-08-06

348

Assessment of natural radioactivity levels and radiation hazards due to cement industry.  

PubMed

The cement industry is considered as one of the basic industries that plays an important role in the national economy of developing countries. Activity concentrations of (226)Ra, (232)Th and (40)K in Assiut cement and other local cement types from different Egyptian factories has been measured by using gamma-ray spectrometry. From the measured gamma-ray spectra, specific activities were determined. The measured activity concentrations for these natural radionuclides were compared with the reported data for other countries. The average values obtained for (226)Ra, (232)Th and (40)K activity concentration in different types of cement are lower than the corresponding global values reported in UNSCEAR publications. The obtained results show that the averages of radiation hazard parameters for Assiut cement factory are lower than the acceptable level of 370Bqkg(-1) for radium equivalent Ra(eq), 1 for level index Igammar, the external hazard index Hex radiation hazard parameters. Cement does not pose a significant radiological hazard when used for construction of buildings. PMID:19818635

El-Taher, A; Makhluf, S; Nossair, A; Abdel Halim, A S

2009-09-09

349

Complete suppression of reverse annealing of neutron radiation damage during active gamma irradiation in MCZ Si detectors  

NASA Astrophysics Data System (ADS)

For the development of radiation-hard Si detectors for the SiD BeamCal (Si Detector Beam Calorimeter) program for International Linear Collider (ILC), n-type Magnetic Czochralski Si detectors have been irradiated first by fast neutrons to fluences of 1.51014 and 31014 neq/cm2, and then by gamma up to 500 Mrad. The motivation of this mixed radiation project is to test the radiation hardness of MCZ detectors that may utilize the gamma/electron radiation to compensate the negative effects caused by neutron irradiation, all of which exists in the ILC radiation environment. By using the positive space charge created by gamma radiation in MCZ Si detectors, one can cancel the negative space charge created by neutrons, thus reducing the overall net space charge density and therefore the full depletion voltage of the detector. It has been found that gamma radiation has suppressed the room temperature reverse annealing in neutron-irradiated detectors during the 5.5 month of time needed to reach a radiation dose of 500 Mrad. The room temperature annealing (RTA) was verified in control samples (irradiated to the same neutron fluences, but going through this 5.5 month RTA without gamma radiation). This suppression is in agreement with our previous predictions, since negative space charge generated during the reverse annealing was suppressed by positive space charge induced by gamma radiation. The effect is that regardless of the received neutron fluence the reverse annealing is totally suppressed by the same dose of gamma rays (500 Mrad). It has been found that the full depletion voltage for the two detectors irradiated to two different neutron fluences stays the same before and after gamma radiation. Meanwhile, for the control samples also irradiated to two different neutron fluences, full depletion voltages have gone up during this period. The increase in full depletion voltage in the control samples corresponds to the generation of negative space charge, and this increase in concentration of negative space charge goes up with the neutron fluence. If we assume the reverse annealing is also taking place for the two gamma-irradiated samples with similarly different concentrations of negative space charge generated, the observed effect of no changes in space charge (no changes in Vfd) in these two gamma-irradiated samples would imply that concentrations of positive space charge created in these two control samples are different at the same gamma dose, and gamma irradiation effectively "switched off", the RT (room temperature) reverse annealing of neutron irradiation. It has also been found that as soon as the gamma irradiation stops, the RT reverse annealing of neutron irradiation-induced defects resumes with same rate as that of the control detectors. This behavior in mixed radiation samples (neutron plus gamma) would suggest some nonlinear effect (defects induced by mixed-radiations are not additive of those by individual radiation alone), or interaction of radiation induced acceptor-type and donor-type defects.

Li, Z.; Verbitskaya, E.; Chen, W.; Eremin, V.; Gul, R.; Hrknen, J.; Hoeferkamp, M.; Kierstead, J.; Metcalfe, J.; Seidel, S.

2013-01-01

350

Gamma-radiation-induced changes in structure and properties of tetracalcium phosphate and its derived calcium phosphate cement.  

PubMed

The purpose of the present study was to investigate the gamma-radiation effect on the structure and properties of the single-phase tetracalcium phosphate (TTCP) powder and its derived calcium phosphate cement (CPC). Experimental results show that low-dosed (0-30 kGy) CPC has a setting time of 10-12 min, while high-dosed (40-120 kGy) CPC has a setting time of 8-10 min. The low dose gamma-radiation does not significantly change porosity volume fraction or compressive strength of the CPC. The pH values of all CPC samples fell in a relatively narrow band, with a band width of 8.5-9.1 (in terms of pH value). With a dose of 10 or 20 kGy gamma-radiation, the TTCP-apatite conversion ratio does not change much. With 30 kGy the conversion ratio significantly increases and reaches a maximum value. With further increases in dose, the conversion ratio quickly declines. With increasing gamma-ray dose, the CPC morphology becomes more porous/loose and apatite particles become larger in size. When exposed to a high dose (120 kGy) of gamma-radiation, TTCP structure is radiation-damaged, and gamma-ray-induced formation of apatite is confirmed by transmission electron microscopic/selected-area diffraction/lattice imaging analyses. PMID:16850475

Tsai, Chih-Hung; Lin, Jiin-Huey Chern; Ju, Chien-Ping

2007-01-01

351

Kinetics of the radiation-induced radicals in gamma irradiated solid cefazolin sodium  

NASA Astrophysics Data System (ADS)

Room and high temperature kinetic and spectroscopic features of the radical species produced in gamma irradiated cefazolin sodium (here after CS) were investigated in detail using electron spin resonance (ESR) spectroscopy to determine the feasibility of its sterilization by radiation and to explore the dosimetric properties of this semi-synthetic representative of cephalosporins. Irradiated CS exhibits an unresolved ESR doublet as other cephalosporins reported up to date. Signal intensity data derived from microwave saturation, dose-response, decays at room and at high temperature studies were analysed assuming a model of two radical species giving rise to doublet and singlet ESR signals. Spectroscopic parameters of these species were determined through spectrum simulation calculations. Decay parameters calculated from annealing studies at seven different temperatures were used to calculate the activation energies of the contributing species. Radiosensitivity of CS to gamma rays was found to be relatively low in the dose range of 0-25 kGy. This conclusion was considered as an indication of the feasibility of radiosterilization of CS by gamma radiation. Five different functions were tried to explore dose-response data of CS in the dose range of 0-25 kGy and it was concluded that a function comprising a linear and a quadratic terms of applied dose describes best experimental results.

Yurus, S.; Korkmaz, M.

2005-01-01

352

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

NASA Astrophysics Data System (ADS)

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

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

2008-07-01

353

New study sees greater low-level radiation threat  

Microsoft Academic Search

A new analysis of Energy Department medical records has found higher than expected cancer rates among workers at DOE's Hanford nuclear weapons plant, suggesting occupational exposure to low-level radiation may be more dangerous than previously thought. The study, released Tuesday by the Philadelphia-based Three Mile Island Public Health Fund, is important not only because of its controversial conclusions, but also

Lobsenz

1992-01-01

354

Health Effects of Exposure to Low-Level Ionizing Radiation  

Microsoft Academic Search

This book comprises chapters contributed, with one exception, by American scientists and physicians and inevitably it is very much biased towards the American scene. Even so, the rest of us can draw parallel with our own societies. The book is aimed towards a medical audience and those in the radiation protection business, whose professional lives revolve around low level exposures,

David Lloyd

1997-01-01

355

10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.  

Code of Federal Regulations, 2010 CFR

...Limits on external radiation levels from storage containers and source changers. 34...INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS...Limits on external radiation levels from storage containers and source changers....

2009-01-01

356

10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.  

Code of Federal Regulations, 2010 CFR

...Limits on external radiation levels from storage containers and source changers. 34...INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS...Limits on external radiation levels from storage containers and source changers....

2010-01-01

357

41 CFR 50-204.35 - Application for variations from radiation levels.  

Code of Federal Regulations, 2013 CFR

...false Application for variations from radiation levels. 50-204.35 Section...STANDARDS FOR FEDERAL SUPPLY CONTRACTS Radiation Standards § 50-204.35 Application for variations from radiation levels. (a) In accordance...

2013-07-01

358

49 CFR 173.441 - Radiation level limitations and exclusive use provisions.  

Code of Federal Regulations, 2010 CFR

...or unnecessarily result in increased radiation levels or radiation exposures to transport workers or members of the general public...package exceeding the maximum surface radiation level or maximum transport index prescribed in paragraph...

2009-10-01

359

49 CFR 173.441 - Radiation level limitations and exclusive use provisions.  

Code of Federal Regulations, 2010 CFR

...or unnecessarily result in increased radiation levels or radiation exposures to transport workers or members of the general public...package exceeding the maximum surface radiation level or maximum transport index prescribed in paragraph...

2010-10-01

360

Features of the action of low-energy gamma radiation on the hydrogen permeability of certain materials  

SciTech Connect

This paper determines the diffusion coefficients, the constants of permeability, and solubility of hydrogen in palladium, nickel, and Armco iron under the action of low-energy gamma radiation. It was established that without radiation all of the kinetic diffusion curves of hydrogen in palladium and nickel straighten well in a functional scale. In armco iron, some deviations are observed.

Tazhibaeva, I.L.; Bekman, I.N.; Rudenko, N.V.; Shestakov, V.P.

1985-07-01

361

Recurrent tumor vs radiation effects after Gamma Knife radiosurgery of intracerebral metastases: Diagnosis with PET-FDG  

Microsoft Academic Search

Our objective was to differentiate radiation effects from tumor progression in metastases stereotaxically irradiated with the multicobalt unit (Gamma Knife). Eleven patients with stereotaxically irradiated cerebral metastases were examined with PET using [¹⁸F]fluorodeoxyglucose (FDG) to differentiate recurrent tumor from radiation effects. Six patients had increased uptake of FDG, and clinical, radiological, and pathological findings confirmed the diagnosis of recurrent metastases.

Jan Mogard; L. Kihlstroem; Kaj Ericson; Bengt Karlsson; Wan-Yuo Guo; Sharon Stone-Elander

1994-01-01

362

Overview of low-level radiation exposure assessment: biodosimetry.  

PubMed

The capability to make diagnostic assessments of radiation exposure is needed to support triage of radiation casualties and medical treatment decisions in military operations. At the International Conference on Low-Level Radiation Injury and Medical Countermeasures session on biodosimetry in the military, participants reviewed the field of biomarkers, covering a wide range of biological endpoints. Participants evaluated early changes associated with exposure to ionizing radiation, including chromosomal and DNA damage, gene expression and associated proteins, and DNA mutations. The use and development of advanced monitoring and diagnostic technologies compatible with military operations was emphasized. Conventional radiation bioassays require a substantial amount of time between when the sample is taken and when the data can be provided for decision making. These "reach back" bioassays are evaluated in laboratories that are not in the field; these laboratories routinely measure exposures of 25 cGy (photon equivalent levels). Detection thresholds can be reduced approximately fivefold by the addition of significant and tiresome scoring efforts. Alternative real-time biomarkers that can be measured in field laboratories or with handheld detection devices show promise as screening and clinical diagnostic tools, but they require further development and validation studies. PMID:11873504

Blakely, William F; Brooks, Antone L; Lofts, Richard S; van der Schans, Govert P; Voisin, Philippe

2002-02-01

363

Effect of gamma cobalt ($gamma$ ⁶°Co) radiation on the growth and alkaloidal contents of medicinal plants. Part I. Hyoscyamus niger L. (Solanaceae)  

Microsoft Academic Search

Henbane (Hyoscyamus niger) is cultivated for the biosynthesis of ; alkaloids, especially hyoscyamine, used by the pharmaceutical industry that are ; present in most plant parts, particularly in the leaves and flowering tops. ; Seeds of henbane were irradiated with doses of 1, 1.5, 2, 2.5, or 3 Krads gamma ; radiation, and plants grown from the irradiated seeds were

S. Malik; M. Akram; N. A. Malik

1972-01-01

364

Decontamination du poivre noir et du poivre rouge par irradiation gamma. (Decontamination of black pepper and red pepper by gamma radiation).  

National Technical Information Service (NTIS)

In the present work, it has been studied the decontamination of two types of spices (black pepper and red pepper) by gamma radiation. The initial microbial population of spices not treated is about 10 (7) to 10 (8) per gram. The population decrease expone...

S. Oularbi B. Mansouri

1993-01-01

365

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

USGS Publications Warehouse

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

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

1972-01-01

366

Reduction of Quark Mass Scheme Dependence in B bar -> Xs gamma at the NNLL Level  

SciTech Connect

The uncertainty of the theoretical prediction of the B {yields} X{sub s}{gamma} branching ratio at NLL level is dominated by the charm mass renormalization scheme ambiguity. In this paper we calculate those NNLL terms which are related to the renormalization of m{sub c}, in order to get an estimate of the corresponding uncertainty at the NNLL level. We find that these terms significantly reduce (by typically a factor of two) the error on BR(B {yields} X{sub s}{gamma}) induced by the definition of m{sub c}. Taking into account the experimental accuracy of around 10% and the future prospects of the B factories, we conclude that a NNLL calculation would increase the sensitivity of the observable B {yields} X{sub s}{gamma} to possible new degrees of freedom beyond the SM significantly.

Asatrian, H.M.; /Yerevan Phys. Inst.; Greub, C.; /Bern U.; Hovhannisyan, A.; /Yerevan Phys. Inst.; Hurth, T.; /CERN /SLAC; Poghosyan, V.; /Yerevan Phys. Inst.

2005-06-20

367

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

SciTech Connect

The effects of low-dose (1 kGy) gamma radiation and selected phosphates on the microbiology of refrigerated, vacuum-packaged ground pork were studied. Low-dose gamma radiation reduced the numbers of naturally occurring mesophiles, psychrotrophs, and anaerobes. The effect of low-dose radiation on the populations of lactic acid bacteria was minimal. On storage of the irradiated vacuum-packaged ground pork at 5/sup 0/C, there was a partial bacterial recovery, suggesting sublethal bacterial injury due to irradiation. When 10/sup 7/ CFU/g of meat is taken to be the level beyond which the meat would be considered spoiled, uninoculated, vacuum-packaged ground pork treated with 1 kGy (100 krad) of gamma radiation had 3.5 more days of shelf-life in terms of psychrotrophic total counts. In relation to anaerobic bacterial numbers, meat shelf-life was extended 2.5 days, while the shelf-life of meat was extended 1 day in terms of aerobic mesophilic bacteria. Irradiation prolonged shelf-life in inoculated (10/sup 5/CFU/g) meat for 1.0-1.5 days. Addition of 0.4% sodium acid pyrophosphate (SAPP) contributed 2 additional days to inoculated, irradiated vacuum-packaged ground pork shelf-life. However, SAPP had no added effect on naturally occurring microflora. Irradiation greatly decreased the numbers of gram-negative microorganisms, resulting in predominance of the gram-positive, nonsporeforming Lactobacillus and coryneform bacteria.

Ehioba, R.M.

1987-01-01

368

Size Effects on Gamma Radiation Response of Magnetic Properties of Barium Hexaferrite Powders  

SciTech Connect

Little is currently known about the effects of gamma-ray irradiation on oxide magnet materials. In particular, the effect of particle size on radiation susceptibility was investigated. Two commercial powders of BaFe12O19 were thoroughly characterized, then exposed to 1 MGy of gamma radiation from a 60Co source. AC susceptibility and DC magnetometry and Moessbauer spectroscopy were performed after irradiation and compared to pre-irradiated measurements. DC magnetization and AC susceptibility decreased for both samples with the relative change of DC magnetization being larger for the micrometer-sized particles and the relative change of the AC susceptibility being larger for the nanometer-sized particles. Moessbauer spectroscopy indicated a decrease in both the hyperfine fieldsand in the distribution of hyperfine fields for each Fe site, particularly in the larger particle sample. Decreases in susceptibility are believed to be due to recrystallization of the particles and redistribution of an amorphous component, in the bulk or on the surface, and consequent reduction in the particle magnetic moment. This radiation damage mechanism is different than that seen in previous studies of neutron and heavy ion irradiation of BaFe12O19.

McCloy, John S.; Kukkadapu, Ravi K.; Crum, Jarrod V.; Johnson, Bradley R.; Droubay, Timothy

2011-12-08

369

Gamma radiation dosimetry using transmission and reflection spectroscopy of KClxBr1-x as TL crystals  

NASA Astrophysics Data System (ADS)

In this article we have shown that it is possible to use transmission, absorption and reflection spectroscopic data of KClxBr1-x single crystals for the TL (Thermo Luminescence) dosimetry purposes in the spectral range of 250-750 nm. The effects of gamma radiation on KClxBr1-x single crystals were investigated by radiating the samples with a 60Co source and studying the reflection and absorption spectra. Six doses of gamma radiation of 145, 300, 450, 600, 750 and 900 Gy were examined. The absorption peak height in the spectral region of 560-580 nm is in a direct relationship with the gamma radiation doses up to about 800 Gy, in which saturation starts to occur. The intensities of the color centers in mixed crystals are different by their combination ratios of the components contents. According to the reflection and transmission data, the absorption spectra can be calculated and a calibration curve sketched.

Ahad Bagheri, S.; Malekfar, R.

2010-03-01

370

Effect of solvents on radiation-induced ionic graft polymerization. [Gamma radiation  

SciTech Connect

The influence of various solvents on radiation-induced cationic (grafting of vinyl-n-butyl ether onto polyethylene) and anionic (grafting of 2-methyl-5-vinylpyridine onto polyethylene) graft polymerization was studied. This ionic grafting was performed in thoroughly dried systems at room temperature. It was established that electron-acceptor solvents promote cationic grafting but that electron-donor solvents promote the anionic. A clear correlation between the donor number of solvents and grafting value by the anionic mechanism was shown. There was no correlation between dielectric constants and grafting values. The reaction orders, according to monomer concentraton by 2-methyl-5-vinylpyridine grafting in various solvents, were equal to approximately 1.5 and 2 for the radical and anionic mechanisms, respectively. The effect of solvents on radiation-induced ionic graft polymerization is discussed. The results of this study indicate the correct choice of solvents for radiation-induced ionic grafting.

Kabanov, V.Ya.; Aliev, R.E.; Sidorova, L.P.

1980-03-01

371

Alterations in damage processes in dense cancellous bone following gamma-radiation sterilization.  

PubMed

Structurally intact cancellous bone allograft is an attractive tissue form because its high porosity can provide space for delivery of osteogenic factors and also allows for more rapid and complete in-growth of host tissues. Gamma radiation sterilization is commonly used in cancellous bone allograft to prevent disease transmission. Commonly used doses of gamma radiation sterilization (25-35 kGy) have been shown to modify cortical bone post-yield properties and crack propagation but have not been associated with changes in cancellous bone material properties. The purpose of this study was to determine the effects of irradiation on the elastic and yield properties and microscopic tissue damage processes in dense cancellous bone. Cancellous bone specimens (13 control, 14 irradiated to 30 kGy) from bovine proximal tibiae were tested in compression to 1.3% apparent strain and examined for microscopic tissue damage. The yield strain in irradiated specimens (0.93+/-0.11%, mean+/-SD) did not differ from that in control specimens (0.90+/-0.11%, p=0.44). No differences in elastic modulus were observed between groups after accounting for differences in bone volume fraction. However, irradiated specimens showed greater residual strain (p=0.01), increased number of microfractures (p=0.02), and reduced amounts of cross-hatching type damage (p<0.01). Although gamma radiation sterilization at commonly used dosing (30 kGy) does not modify elastic or yield properties of dense cancellous bone, it does cause modifications in damage processes, resulting in increased permanent deformation following isolated overloading. PMID:20172526

Dux, S J; Ramsey, D; Chu, E H; Rimnac, C M; Hernandez, C J

2010-02-20

372

Thin films of In2O3/SiO as optical gamma radiation sensors  

NASA Astrophysics Data System (ADS)

This paper explores the use of mixed oxide materials such as In2O3 and SiO with various compositions in the form of thermally deposited thin films for gamma radiation dosimetry application. 137Cs radiation source with an activity of 370 kBq was used for exposing the samples to ?-radiation. The absorption spectra for as-deposited and ?-irradiated films were recorded using CARY 1E UV-Visible Spectrophotometer. The values of the optical band gap Eopt were obtained in the view of the Mott and Davis" theory. It was found that the optical properties of thin films were highly affected by composition and manufacturing conditions. For comparison, Eopt of as-deposited thin film with composition 75 wt.% of In2O3 and 25 wt.% of SiO was found to be 0.9 eV, whereas films with 50 wt.% of In2O3 and 50 wt.% of SiO have Eopt=1.15 eV, in all cases assuming indirect allowed transition. It was noted that Eopt decreased with the increase in radiation dose, i.e. the overall disorder of the system has increased. Thin films of In2O3 and SiO mixtures might be regarded as a cost-effective alternative to the existing commercially available radiation detectors.

Arshak, Khalil; Korostynska, Olga; Henry, John

2004-01-01

373

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

PubMed Central

The use of a gamma radiation process for the elimination of Salmonella from frozen meat is considered with particular reference to the treatment of boned-out horsemeat and kangaroo meat imported into the UK and intended for use as pet meat. Examination of dose/survival curves produced for several serotypes of Salmonella in frozen meat shows that a radiation dose of 06 Mrad. will reduce a population by at least a factor of 105. The influence on the radiation resistance of salmonellas of such factors as preirradiation growth in the meat and temperature during irradiation have been examined and considered. It is also demonstrated with both preinoculated and naturally contaminated meat that postirradiation storage in the frozen state does not lead to the revival of irradiated salmonellas. The properties of Salmonella survivors deliberately produced in meat using conditions of irradiation designed to simulate a commercial process are studied after six recycling treatments through the process. There were no important changes in characteristics normally used for identification of Salmonella but radiation resistance was lowered. Survivors grown in situ in meat after irradiation showed an abnormally long lag phase, and removal of competitive microflora in meat by the radiation treatment can influence the growth of salmonellas.

Ley, F. J.; Kennedy, T. S.; Kawashima, K.; Roberts, Diane; Hobbs, Betty C.

1970-01-01

374

Gamma radiation damage study of 0.18 m process CMOS image sensors  

NASA Astrophysics Data System (ADS)

A 0.18 ?m process CMOS image sensor has recently been developed by e2v technologies plc. with a 0.5 megapixel imaging area consisting of 6 6 ?m 5T pixels. The sensor is able to provide high performance in a diverse range of applications including machine vision and medical imaging, offering good low-light performance at a video rate of up to 60 fps. The CMOS sensor has desirable characteristics which make it appealing for a number of space applications. Following on from previous tests of the radiation hardness of the image sensors to proton radiation, in which the increase in dark-current and appearance of bright and RTS pixels was quantified, the sensors have now been subjected to a dose of gamma radiation. Knowledge of the performance after irradiation is important to judge suitability for space applications and radiation sensitive medical imaging applications. This knowledge will also enable image correction to mitigate the effects and allow for future CMOS devices to be designed to improve upon the findings in this paper. One device was irradiated to destruction after 120 krad(Si) while biased, and four other devices were irradiated between 5 and 20 krad(Si) while biased. This paper explores the resulting radiation damage effects on the CMOS image sensor such as increased dark current, and a central brightening effect, and discusses the implications for use of the sensor in space applications.

Dryer, Ben; Holland, Andrew; Murray, N. J.; Jerram, Paul; Robbins, Mark; Burt, David

2010-07-01

375

Serum levels of interleukin-13 and interferon-gamma from adult patients with asthma in Mysore.  

PubMed

Serum protein analysis for noninvasive quantification of airway inflammation in asthma is a promising research tool in the field of lung diseases. Cytokines are believed to have major role in inflammatory process of the airways of the lung. There is an imbalance between T-helper (Th)-2 cells, which secrete interleukin (IL)-4 and interleukin (IL)-13, and Th1 cells, which secrete interferon (IFN)-gamma in asthma. To test the hypothesis that serum IL-13 and IL-4 levels may be elevated whereas IFN-gamma would be decreased in this cohort of patients, a property that could make them possible candidate biomarkers in determining asthma occurrence and severity, we measured concentrations of IL-4, IL-13 and IFN-gamma in serum samples of 88 subjects (44 normal, 12 with mild asthma, 16 with moderate asthma, and 16 with severe asthma). Serum Levels of IL-4, IL-13, and IFN-gamma were determined by an enzyme-linked immune-sorbent assay (ELISA). Median serum level of IFN-gamma in asthmatic patients was 8.0 pg/ml, while it was 11.4 pg/ml in healthy controls. However, the difference was not significant. Among the different age groups in whom IFN-gamma was assessed, the highest median value in both cases and controls was observed in the age group of 31-40 years. The median serum level of IL-13 was 40.0 pg/ml in asthmatic patients and 58.25 pg/ml in healthy controls. The difference was not significant. On subgroup analysis, no significant difference of IFN-gamma and IL-13 between asthma of different severities was observed. The study also revealed nonsignificant difference of serum cytokines with the duration of asthma, number of allergens, and severity of sensitization. Normal serum levels of IFN-gamma and IL-13 in asthmatic patients suggest their neutral role in the inflammatory process; however, more studies are required to establish the effect of these cytokines in adulthood asthma in different ethnic populations. PMID:22698804

Davoodi, Parisa; Mahesh, P A; Holla, Amrutha D; Vijayakumar, G S; Jayaraj, B S; Chandrashekara, S; Ramachandra, Nallur B

2012-06-12

376

A new technique for processing airborne gamma ray spectrometry data for mapping low level contaminations  

Microsoft Academic Search

A new technique for processing airborne gamma ray spectrometry data has been developed. It is based on the noise adjusted singular value decomposition method introduced by Hovgaard in 1997. The new technique opens for mapping of very low contamination levels. It is tested with data from Latvia where the remaining contamination from the 1986 Chernobyl accident together with fallout from

H. K Aage; U Korsbech; K Bargholz; J Hovgaard

1999-01-01

377

Hyperfine structure of Gamma6 electronic level in cubic Yb compound from Mssbauer spectroscopy  

Microsoft Academic Search

The hyperfine structure of the Gamma6 electronic level in the cubic compound Cs2NaYbCl6 has been observed from the Mssbauer studies of 170Yb. The effective hyperfine coupling constant is found to be -10.9+\\/-0.1 mm\\/sec.

G. K. Shenoy; R. Poinsot; L. Asch; J. M. Friedt; B. D. Dunlap

1974-01-01

378

Effects of alpha and gamma radiation on glass reaction in an unsaturated environment  

SciTech Connect

Radiation may effect the long-term performance of glass in an unsaturated repository site by interacting with air, water vapor, or liquid water. The present study examines (1) the effects of alpha or gamma irradiation in a water vapor environment, and (2) the influence of radiolytic products on glass reaction. Results indicate that nitric and organic acids form in an irradiated water vapor environment and are dissolved in thin films of condensed water. Glass samples exposed to these conditions react faster and have a different assemblage of secondary phases than glasses exposed to nonirradiated water vapor environments. 23 refs., 4 figs., 2 tabs.

Wronkiewicz, D.J.; Young, J.E.; Bates, J.K.

1990-12-31

379

Determination of canine dose conversion factors in mixed neutron and gamma radiation fields. Technical report  

SciTech Connect

The primary objective of mixed-field neutron/gamma radiation dosimetry in canine irradiation experiments conducted at the Armed Forces Radiobiology Research Institute (AFRRI) is to determine the absorbed midline tissue dose (MLT) at the region of interest in the canine. A dose conversion factor (DCF) can be applied to free-in-air (FIA) dose measurements to estimate the MLT doses to canines. This report is a summary of the measured DCFs that were used to determine the MLT doses in canines at AFRRI from 1979 to 1992.

Torres, B.A.; Bhatt, R.C.; Myska, J.C.; Holland, B.K.

1996-07-01

380

Effect of gamma radiation on low density polyethylene (LDPE) films: Optical, dielectric and FTIR studies  

NASA Astrophysics Data System (ADS)

The low density polyethylene (LDPE) films were irradiated with gamma radiation in the dose range varied from 20 to 400 kGy. The induced changes in the chemical structure and dielectric properties for the irradiated films were investigated. The structure modifications: crystallinity as well as possible molecular changes of the polymer were recognized using Fourier Transform Infrared Spectroscopy (FTIR). The optical results were determined from transmission, reflection and absorption spectra for these films. The dielectric properties of these films were calculated using optical methods. Result indicates small variation in crystallinity which could be increased or decreased depending on the relative importance of the structural and chemical changes.

Moez, A. Abdel; Aly, S. S.; Elshaer, Y. H.

381

Effect of gamma radiation on low density polyethylene (LDPE) films: optical, dielectric and FTIR studies.  

PubMed

The low density polyethylene (LDPE) films were irradiated with gamma radiation in the dose range varied from 20 to 400 kGy. The induced changes in the chemical structure and dielectric properties for the irradiated films were investigated. The structure modifications: crystallinity as well as possible molecular changes of the polymer were recognized using Fourier Transform Infrared Spectroscopy (FTIR). The optical results were determined from transmission, reflection and absorption spectra for these films. The dielectric properties of these films were calculated using optical methods. Result indicates small variation in crystallinity which could be increased or decreased depending on the relative importance of the structural and chemical changes. PMID:22481176

Moez, A Abdel; Aly, S S; Elshaer, Y H

2012-02-18

382

Inheritance of induction radiation sensitivity of space flight environments and gamma-radiation on rice  

Microsoft Academic Search

There are many factors affecting living things during space flight, such as microgravity, cosmic radiation, etc. A large number of plant mutants have been obtained after space flight on satellite in China in the last decade and some commercial crop varieties were released. However, little consideration has so far been given to the genetic mechanisms underlying sensitivity of plant seeds

J. Xu; J. Wang; L. Wei; Z. Li; Y. Sun

2004-01-01

383

Prediction of ozone levels using a Hidden Markov Model (HMM) with Gamma distribution  

NASA Astrophysics Data System (ADS)

Ground level ozone, generated by the photochemical reaction between nitrogen oxides and volatile hydrocarbons, is harmful to humans and the environment. Prediction and forecasting play an important role in the regulatory policies aimed at the control and reduction of surface ozone. Belonging to the family of model-driven statistical models, Hidden Markov Models (HMMs) provide a rich mathematical structure and perform well in many applications. While conventional HMM applications assume Gaussian distribution for the observation statistics, several key meteorological factors and most ozone precursors exhibit a non-Gaussian distribution, which would weaken the performance of a conventional HMM in modeling ozone exceedances. We propose a method based on a HMM with a Gamma distribution (HMM-Gamma) where each monitoring day is pre-labeled according to its maximum 8-h average ozone concentration and monitoring days are further grouped into zones with different ozone levels. Then, HMMs associated with each zone are trained using air quality monitoring data where the model parameters are estimated by a modified Expectation-Maximization (EM) algorithm. We derive a new re-estimation formula for the model parameters for observation sequences that exhibit a Gamma distribution. The trained HMM-Gamma models are used to predict ozone exceedances in two geographic areas, Livermore Valley near San Francisco, CA and Houston Metropolitan Area, TX. Compared to the conventional HMM (HMM-Gaussian), HMM-Gamma for the ground level ozone in Livermore Valley can reduce false alarms by 77% and HMM-Gamma for that in Houston Metropolitan Area can reduce false alarms by 32%.

Zhang, Hao; Zhang, Weidong; Palazoglu, Ahmet; Sun, Wei

2012-12-01

384

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

SciTech Connect

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

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

2011-07-01

385

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

PubMed

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

Heisel, M; Kaether, F; Simgen, H

2009-01-23

386

Radiation-induced oxidative degradation of poly(vinyl chloride). [Gamma radiation  

SciTech Connect

Gas evolution and oxygen consumption in the ..gamma..-irradiation of PVC were studied. The gas evolution and the oxidative degradation are retarded by the presence of plasticizers and stabilizers. The G(HCl) and G(H/sub 2/) are 8 and 0.24 for the irradiation of pure PVC under vacuum and 0.02 and 0.14 for that of plasticized PVC, respectively. Gas evolution increases in the presence of oxygen, specially for the pure PVC. The G(-O/sub 2/) values for the pure and plasticized PVC are 30 and 12, respectively. The dependence of gas evolution and oxygen consumption on the oxygen pressure is more pronounced for the plasticized PVC than pure PVC because the oxygen diffusion is controlled.

Hegazy, E.S.A.; Seguchi, T.; Machi, S.

1981-09-01

387

A New Chemical Dosimetry for measuring Higher Level gamma-Rays using a Titanium Sulphate Solution  

Microsoft Academic Search

THE Fricke dosimeter1 using a ferrous sulphate solution and the ceric dosimeter have been used successfully for the estimation of dose of medium-level gamma-rays, namely, those between 103 and 105 r. But these dosimeters have some limitations which are unavoidable when used to measure higher-level doses. An attempt has been made by us to develop a new chemical dosimeter for

Takanobu Shiokawa; K. Hasegawa

1962-01-01

388

The effect of high dose rate transient gamma radiation on high-energy optical fibers  

NASA Astrophysics Data System (ADS)

High power laser systems have a number of uses in a variety of scientific and defense applications, for example laser induced breakdown spectroscopy (LIBS) or laser-triggered switches. In general, high power optical fibers are used to deliver the laser energy from the source to the target in preference to free space beams. In certain cases, such as nuclear reactors, these optical systems are expected to operate in ionizing radiation environments. In this paper, a variety of modern, currently available commercial off-the-shelf (COTS) optical fiber designs have been assessed for successful operation in the transient gamma radiation environment produced by the HERMES III accelerator at Sandia National Laboratories, USA. The performance of these fibers was evaluated for high (~1 MW) and low (<1 W) optical power transmission during high dose rate, high total dose gamma irradiation. A significant reduction in low optical power transmission to 32% of maximum was observed for low OH- content fibers, and 35% of maximum for high OH- fibers. The high OH- fibers were observed to recover to 80% transmission within 1 ?s and 100% transmission within 1 ms. High optical power transmission losses followed generally similar trends to the low optical power transmission losses, though evidence for an optical power dependent recovery was observed. For 10-20 mJ, 15 ns laser pulses, around 46% was transmitted coincident with the radiation pulse, recovering to 70% transmission within 40 ns of the radiation pulse. All fibers were observed to completely recover within a few minutes for high optical powers. High optical power densities in excess of 1 GW/cm2 were successfully transmitted during the period of highest loss without any observed damage to the optical fibers.

Akinci, A.; Bowden, M. D.; Cheeseman, M. C.; Knowles, S. L.; Meister, D. C.; Pecak, S. N.; Simmons Potter, K.

2009-08-01

389

Radiation grafting of methyl methacrylate monomer on natural rubber latex. [Gamma radiation  

SciTech Connect

A method of radiation grafting of methyl methacrylate (MMA) monomer on natural rubber (NR) latex has been studied. The irradiation dose in radiation emulsion polymerization of MMA monomer was lower compared to the irradiation dose for grafting of MMA monomer on NR latex, in order to obtain the same degree of conversion. This is due to the size of the rubber particles which are quite large and, hence, not sufficient to ensure an ideal emulsion polymerization. The irradiation dose for radiation grafting of MMA monomer on latex was around 300 krad to obtain a 75% degree of conversion. However, this irradiation dose was lower compared to the irradiation dose for bulk polymerization of MMA momomer, in order to obtain the same degree of conversion. This is due to the gel effect in the viscous media. Radiation grafting of MMA monomer on NR latex does not influence the pH of the latex, but influences the viscosity significantly. The viscosity of the NR latex increased with an increase in irradiation dose, due to the increase of the total solid content in the latex. The MMA monomer converted to P-MMA in NR latex was largely grafted on the NR, or at least insoluble in a solvent for P-MMA, such as acetone or toluene. The hardness of the pure gum vulcanizate increased with an increase in the degree of grafting or P-MMA content, but the other physical properties, such as tensile strength, modulus, elongation at break, and thermal stability, were not greatly influenced by the degree of grafting. 9 references, 3 figures, 5 tables.

Sundardi, F.; Kadariah, S.

1984-05-01

390

Gamma-thermometer-based reactor-core liquid-level detector. [PWR  

SciTech Connect

A system is provided which employs a modified gamma thermometer for determining the liquid coolant level within a nuclear reactor core. The gamma thermometer which normally is employed to monitor local core heat generation rate (reactor power), is modified by thermocouple junctions and leads to obtain an unambiguous indication of the presence or absence of coolant liquid at the gamma thermometer location. A signal processor generates a signal based on the thermometer surface heat transfer coefficient by comparing the signals from the thermocouples at the thermometer location. The generated signal is a direct indication of loss of coolant due to the change in surface heat transfer when coolant liquid drops below the thermometer location. The loss of coolant indication is independent of reactor power at the thermometer location. Further, the same thermometer may still be used for the normal power monitoring function.

Burns, T.J.

1981-06-16

391

Gamma-magnetic normalization - new effect to reduce flux-gate magnetometer noise level  

NASA Astrophysics Data System (ADS)

It is the author's opinion confirmed by numerous experiments, that the FGM noise level (NL) is determined not by Barkhausen jumps during the core remagnetization from positive to negative state as the majority of designers believe, but by non-repeatability of the magnetic domains transition from negative to positive states and back. This shows the way how to reduce the magnetic noise: to manufacture the magnetic material with a structure which will create conditions for magnetic domain walls to glide easily and uniformly when changing their orientation leading to minimal efforts at cyclic remagnetization. Ideally, such a material may be represented as a solid "liquid" with freely floating uniform magnetic domains without walls friction. To reduce the specific NL of the materials, several post-melting processing technologies were developed. A set of experiments made by many investigators has shown that the best results gives the magnetic materials annealing in vacuum or in any inert gas applying by this during all annealing time the alternative magnetic field, imitating core excitation field during FGM operation. If to accept the "solid liquid" model, this mechanism of NL decreasing has clear physical explanation: permanent re-magnetization of domains leads to the structural improvements favorable namely for the homogenization of transitions, rise of temperature gives necessary energy for the impurities liquidation. Probably, M. Acuna was the first who reported that during FGM operation in space its NL is decreasing with time and attributed this to the relaxation of mechanical stresses in the core material in weightlessness conditions [1]. We studied in details the conditions in which the core material is in space: weightlessness, vacuum and radiation. Mechanical stresses relaxation hypothesis was rejected because the internal forces in any solid body are much stronger as those to which a gravity force might have influence. Also the tests of FGM sensor in vacuum chamber both in operation and switched off conditions showed any influence of this parameter on NL. And radiation influence, the dose of which was selected approximately equal to yearly dose at near-Earth orbit (~10 krad), revealed interesting facts: the magnetic material itself and the FGM sensor in non-operation state showed any dependence on radiation, whereas this dose applied to the operating FGM sensor lead to the marked NL reducing. This new effect was named "gamma-magnetic normalization" and also can be explained by the accepted model: the mechanism is the same as above, but, because ?-quantum have much greater energy as thermal one, more "rigid" impurities are eliminated at ?-radiation action. The experimental results confirming this hypothesis are presented in the report. This work was partially supported by NASU Contract 1-71/11/1531. [1] Acuna M M, 2002. Space based magnetometers. Rev. Sci. Instr. 73(11) pp. 3717-36.

Korepanov, V.

2012-04-01

392

Degradation of chitosan and sodium alginate by gamma radiation, sonochemical and ultraviolet methods  

NASA Astrophysics Data System (ADS)

Three degradation methods: ultrasonic, ultraviolet and gamma irradiation were applied to sodium alginate and chitosan in aqueous solutions. The changes in molecular weight were monitored by GPC measurements. It has been found that from the energetic point of view the most effective method for both polymers is gamma radiation method with a yield of scission G=0.5510mol/J for 1% alginate and G=3.5310mol/J for 1% chitosan. However, considering the reaction time, the ultraviolet method is the most effective, with reaction rate constant k=0.52h for alginate and 1.6 h-1 for chitosan. Based on FTIR spectra, taken before and after degradation it was revealed, that degradation undergoes by the breakage of the glycosidic bonds of polymers. UV spectroscopy showed absorption peak at 265 nm for alginate, and two peaks at the range of 250 280 nm for chitosan. UV spectroscopy for ultrasonic is not revealed and any peak suggesting ultrasonic degradation undergoes different mechanism than ultraviolet and gamma degradations, probably mechanical one.

Wasikiewicz, Jaroslaw M.; Yoshii, Fumio; Nagasawa, Naotsugu; Wach, Radoslaw A.; Mitomo, Hiroshi

2005-08-01

393

Search for ultra-high energy radiation from gamma-ray bursts  

NASA Astrophysics Data System (ADS)

A recent class of models suggests that some gamma-ray bursters may produce ultra-high-energy (greater than or equal to 100 TeV) photons. Using data from the CYGNUS array, we have searched for evidence of emission of ultra-high-energy radiation coincident with gamma-ray bursts observed either by the third Interplanetary Network of satellites or by the Burst and Transient Source Experiment (BATSE) instrument on the Compton Gamma-Ray Observatory. No statistically significant excess was found for six bursts whose locations were accurately determined by the Network, or for any point in the sky within 2 sigma of the BATSE location coordinates of 52 additional bursts. Flux upper limits depend greatly on the zenith angles of the bursts, but typical limits above 100 TeV are approximately 4 x 10-10/sq cm(s). The flux upper limits for three of the bursts imply that the observed spectrum softens between 2 MeV and approximately 100 TeV. If the production spectrum does not soften between these energies, the bursts must have a cosmological origin.

Alexandreas, D. E.; Allen, G. E.; Berley, D.; Biller, S.; Burman, R. L.; Cavalli-Sforza, M.; Chang, C. Y.; Chen, M. L.; Chumney, P.; Coyne, D.; Dion, C.; Dion, G. M.; Dorfan, D.; Ellsworth, R. W.; Goodman, J. A.; Haines, T. J.; Harmon, M.; Hoffman, C. M.; Kelley, L.; Klein, S.; Nagle, D. E.; Schaller, S. C.; Schmidt, D. M.; Schnee, R.; Shoup, A.; Sinnis, C.; Stark, M. J.; Weeks, D. D.; Williams, D. A.; Wu, J.-P.; Yang, T.; Yodh, G. B.; Zhang, W.

1994-05-01

394

THE EFFECT OF IONIZING RADIATION UPON $gamma$-AlO AS A CATALYST FOR H-D EXCHANGE  

Microsoft Academic Search

Relatively small doses of gamma rays at -78 deg C have been found to ; enhance the H--D exchange activity of gamma AlO. ; The enhancement by radiation depends upon the presence of a catalyst poison, H\\/; sub 2\\/O, H or CH and in the case of HO is a function ; of the extent of poisoning, being greatest for

H. W. Kohn; E. H. Taylor

1959-01-01

395

The Appearance of Primeval Galaxies in X- and gamma-Ray Regions and Their Contributions to the Background Radiation  

Microsoft Academic Search

By studying the chemical evolution of a galaxy, its optical, infra-red, X- and gamma-ray luminosities and the integrated background radiation due to these galaxies in their early flashing era are calculated. We conclude that these primeval galaxies are more detectable in X- and gamma-ray regions than in the infra-red region. In 1 keV and 100 MeV regions, much part of

Y. Tanaka; S. Ikeuchi

1979-01-01

396

EFFECT OF $gamma$RADIATION ON THE SHAPE OF MOSSBAUER RESONANCE ABSORPTION SPECTRA IN TIN-ORGANIC COMPOUNDS  

Microsoft Academic Search

The effect of gamma radiation on the shape of the spectra of Mossbauer ; resonance absorption of 23.8-kev gamma quanta in tin-organic compounds is ; investigated. The change in the spectrum for the compound (CH)\\/sub ; 2\\/ SnSO corresponds to splitting of the compound and formation of the ; compounds SnSO and possibly (CH) SnSO (upon ; irra diation in

A. Yu. Aleksandrov; N. N. Delyagin; K. P. Mitrofanov; L. S. Polak; V. S. Shpinel

1962-01-01

397

EGRET detection of high-energy gamma radiation from the OVV quasar 3C 454.3  

Microsoft Academic Search

High-energy gamma radiation has been observed from the optically violent variable quasar 3C 454.3 (PKS 2251 + 158) by the Energetic Gamma-Ray Experiment Telescope on the Compton Observatory. During the 1992 January-February observation, the emission showed a power-law photon spectrum with an exponent of -2.18 +\\/- 0.08. The flux density (greater than 100 MeV) was observed to vary within the

R. C. Hartman; D. L. Bertsch; B. L. Dingus; C. E. Fichtel; S. D. Hunter; G. Kanbach; D. A. Kniffen; Y. C. Lin; J. R. Mattox; H. A. Mayer-Hasselwander; P. F. Michelson; C. von Montigny; P. L. Nolan; B. G. Piner; E. Schneid; P. Sreekumar; D. J. Thompson

1993-01-01

398

Gamma radiation consequences on desert locust Schistocerca gregaria (Forsk.) digestive system.  

PubMed

Schistocera gregaria (Forsk.) (Orthoptera, Acrididae) remains a major insect pest in Africa, more particularly in the Sahelian zone. Present control methods are only partially efficient. In a previous study, we tested the potentiality of a sterile insect technique (SIT). Males of S. gregaria appeared to be much radiosensitive as already a dose of 3 Gy limited their survival. Gamma-radiations are known to damages the epithelial tissue of midgut, which affects the alimentation in insects. In this work, we show how digestive system of S. gregaria males is affected when submitted to a dose of 4 gamma rays. Nutrition is affected as males stop feeding soon after irradiation and progressively lose weight. Histological analyses on the midgut showed important epithelium damages. The regenerative cells by which the epithelial cells are replaced were damaged on the first days following irradiation. Consequently, regenerative cells are unable to divide and replace the normal loss of midgut cell. After nine days, the entire midgut epithelium was destroyed and only longitudinal muscles layer remained intact. This indicates that low radiation doses should be used if SIT will be applied. PMID:21539264

Dushimirimana, S; Muratori, F; Damiens, D; Hance, T

2010-01-01

399

Improvement of microbiological safety of sous-vide meals by gamma radiation  

NASA Astrophysics Data System (ADS)

Experimental batches of smoked-cured pork in stewed beans sauce were inoculated with spores of psychrotrophic Bacillus cereus, more heat and radiation resistant than spores of non-proteolytic C. botulinum. After vacuum packaging, the meals were treated with combinations of pasteurizing heat treatments and gamma irradiation of 5kGy. Prior and after treatments, and periodically during storage at 10C, total aerobic and total anerobic viable cell counts, and selectively, the viable cell counts of B. cereus and sulphite-reducing clostridia have been determined. The effects of the treatment order as well as addition of nisin to enhance the preservative efficiency of the physical treatments were also studied. Heat-sensitization of bacterial spores surviving irradiation occurred. The quality-friendly sous-vide cooking in combination with this medium dose gamma irradiation and/or nisin addition increased considerably the microbiological safety and the keeping quality of the meals studied. However, approx. 40% loss of thiamin content occurred as an effect of combination treatments, and adverse sensorial effects may also limit the feasible radiation doses or the usable concentrations of nisin.

Farkas, J.; Polyk-Fehr, K.; Andrssy, .; Mszros, L.

2002-03-01

400

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

SciTech Connect

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

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

1988-10-01

401

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

SciTech Connect

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

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

1998-08-01

402

Advances in commercial application of gamma radiation in tropical fruits at Brazil  

NASA Astrophysics Data System (ADS)

All regions of Brazil are potential areas for growing tropical fruits. As this country is already a great producer and exporter of tropical fruits, ionizing radiation has been the subject of studies in many commodities. An important project has been carried out to increase the commercial use of gamma radiation in our country. Instituto de Pesquisas Energeticas e Nucleares (IPEN)-CNEN/SP together with field producers in northeast region and partners like International Atomic Energy Agency (IAEA), CIC, Empresa Brasileira Pesquisa na Agricultura (EMBRAPA) joined to demonstrate this technology, its application and commercial feasibility. The objective of this study is to show advances in feasibility demonstrate the quality of the irradiated fruits in an international consignment from Brazil to Canada. In this work, Tommy Atkins mangoes harvested in northeast region of Brazil were sent to Canada. The fruits were treated in a gamma irradiation facility at doses 0.4 and 1.0 kGy. The control group was submitted to hydrothermal treatment (46 C for 110 min). The fruits were stored at 11 C for 10 days until the international transportation and kept at an environmental condition (22 C) for 12 days, where their physical-chemical and sensorial properties were evaluated. The financial part of the feasibility study covers the scope of the investment, including the net working capital and production costs.

Sabato, S. F.; Silva, J. M.; Cruz, J. N.; Broisler, P. O.; Rela, P. R.; Salmieri, S.; Lacroix, M.

2009-07-01

403

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

SciTech Connect

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

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

1985-05-01

404

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

SciTech Connect

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

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

1989-08-01

405

Occupational exposure to radon and natural gamma radiation in the La Carolina, a former gold mine in San Luis Province, Argentina.  

PubMed

Radon and gamma radiation level measurements were carried out inside the La Carolina mine, one of the oldest gold mining camps of southern South America, which is open for touristic visits nowadays. CR-39 track-etch detectors and thermoluminescent dosimeters of natural CaF(2) and LiF TLD-100 were exposed at 14 points along the mine tunnels in order to estimate the mean (222)Rn concentration and the ambient dose equivalent during the summer season (November 2008 to February 2009). The values for the (222)Rn concentration at each monitoring site ranged from 1.8+/-0.1 kBqm(-3) to 6.0+/-0.5 kBqm(-3), with a mean value of 4.8 kBqm(-3), indicating that these measurements exceed in about three times the upper action level recommended by ICRP for workplaces. The correlations between radon and gamma radiation levels inside the mine were also investigated. Effective doses due to (222)Rn and gamma rays inside the mine were determined, resulting in negligible values to tourists. Considering the effective dose to the mine tourist guides, values exceeding 20mSv of internal contribution to the effective doses can be reached, depending on the number of working hours inside the mine. PMID:19945773

Anjos, R M; Umisedo, N; da Silva, A A R; Estellita, L; Rizzotto, M; Yoshimura, E M; Velasco, H; Santos, A M A

2009-11-28

406

SOLIDIFICATION TESTING FOR A HIGH ACTIVITY WASTESTREAM FROM THE SAVANNAH RIVER SITE USING GROUT AND GAMMA RADIATION SHEILDING MATERIALS - 10017  

SciTech Connect

The U.S. Department of Energy (DOE) tasked MSE Technology Applications, Inc. (MSE) with evaluating grouts that include gamma radiation shielding materials to solidify surrogates of liquid aqueous radioactive wastes from across the DOE Complex. The Savannah River Site (SRS) identified a High Activity Waste (HAW) that will be treated and solidified at the Waste Solidification Building (WSB) for surrogate grout testing. The HAW, which is produced at the Mixed Oxide Fuel Fabrication Facility (MFFF), is an acidic aqueous wastestream generated by the alkaline treatment process and the aqueous purification process. The HAW surrogate was solidified using Portland cement with and without the inclusion of different gamma radiation shielding materials to determine the shielding material that is the most effective to attenuate gamma radiation for this application.

Burns, H.

2009-11-10

407

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

NASA Astrophysics Data System (ADS)

This study is aimed of producing pilot batches of hydrogel wound dressings by gamma radiation and evaluating their shelf stability. Six batches of 3L capacity were prepared based on poly(vinyl pyrrolidone), agar and polyethylene glycol and they were dispensed in polyester trays, covered with polyester films and sealed in two types of materials: polyethylene bags and vacuum polyethylene bags. Dressings were formed in a single step process for the hydrogel formation and sterilization at 25-30 kGy gamma radiation dose in a JS-9500 Gamma Irradiator (Nordion, Canada). The six batches were initially physicochemical characterized in terms of dimensions and appearance, gel fraction, morphology analysis, hydrogel strength, moisture retention capability and swelling capacity. They were kept under two storage conditions: room temperature (T: 302 C/RH: 70 5%) and refrigerated temperature (T: 53 C) during 24 months and sterility test was performed. The appearance of membranes was transparent, clear, uncut and flexible; the gel fraction of batches was higher than 75% and the hydrogel surface showed a porous structure. There was a slow decrease of the compression rate 20% until 7 h and about 70% at 24 h. Moisture retention capability in 5 h was similar for all the batches, about 40% and 60% at 37 C and at room temperature respectively. The swelling of hydrogels in acidic media was strong and in alkaline media the weight variation remains almost stable until 24 h and then there is a loss of weight. The six batches remained sterile during the stability study in the conditions tested. The pilot batches were consistent from batch to batch and remained stable during 24 months.

Soler, Dulce Mara; Rodrguez, Yanet; Correa, Hector; Moreno, Ailed; Carrizales, Lila

2012-08-01

408

GaAs semi-insulator detector for gamma and charged-particle radiation  

NASA Astrophysics Data System (ADS)

Silicon positive-intrinsic-negative (p-i-n) diodes have been used in plasma diagnostics by the Los Alamos and Lawrence Livermore National Laboratories (LANL and LLNL) since the early seventies. Since the response bandwidth of these detectors is relatively poor (typically, approximately 5 ns FWHM for 1 cm(superscript 2) sensitive area and 250 micrometers depletion depth), they are too slow for high-speed applications. GaAs photoconductive detectors (PCD) have been developed since the early eighties at LANL and later at LLNL, and can be tailored by judicious neutron damage to provide the required high-speed bandwidth. Unfortunately, for surface absorbed or non-penetrating radiation, we have discovered that the PCD sensitivity is not flat across its gap, where the incident radiation is perpendicular to the bias electric field. This response non-uniformity can lead to erroneous measurements in cases where the radiation is spatially varying. To overcome this problem, we reoriented the GaAs chip to allow the radiation to be incident through the electrode and parallel to the bias electric field. Then to increase bandwidth, we doped the GaAs crystal with chromium to create trapping sites and provide large resistivity (approximately 10(superscript 9) (Omega) cm), thus creating a semi-insulator detector (SID). We present and discuss the merits of the SID versus PCD and p-i-n diode by showing pulse response data of each detector characterized with 16 MeV endpoint gamma and electron radiation created by the EG&G/EM linear accelerator (Linac) and 5 to 16.5 MeV proton radiation produced by the LLNL Tandem Van de Graaff (TVDG). Application of the SID in Compton electron spectrometry also is discussed.

Moy, Kenneth J.; Wang, Ching L.; Flatley, John E.; Pocha, Michael D.; Davis, Brent A.; Wagner, Ronald S.

1992-12-01

409

Response of a gamma-ray telescope dosimeter to the (n + (GAMMA)) radiation from a (239)Pu-Be source  

Microsoft Academic Search

The design, construction, and investigation of a gamma-ray telescope that can tell the direction of incident photons is reported. The dosimeter is based on LiF thermoluminescence. The gamma-ray telescope dosimeter was tested with a (239)Pu-Be source and found to perform satisfactorily. For a high-energy neutron field the gamma-ray telescope dosimeter contributes very little to the total dose equivalent.

F. H. Attix; D. W. Pearson; P. M. Deluca Jr.

1985-01-01

410

Response of a. gamma. -ray ''telescope'' dosimeter to the (n +. gamma. ) radiation from a /sup 239/Pu-Be source  

SciTech Connect

The design, construction, and investigation of a gamma-ray telescope that can tell the direction of incident photons is reported. The dosimeter is based on LiF thermoluminescence. The gamma-ray telescope dosimeter was tested with a /sup 239/Pu-Be source and found to perform satisfactorily. For a high-energy neutron field the gamma-ray telescope dosimeter contributes very little to the total dose equivalent. (LEW)

Attix, F.H.; Pearson, D.W.; DeLuca, P.M. Jr.

1985-01-01

411

Precise Measurement of the e+e--->pi+pi-(gamma) Cross Section with the Initial State Radiation Method at BABAR  

Microsoft Academic Search

A precise measurement of the cross section of the process e+e--->pi+pi-(gamma) from threshold to an energy of 3 GeV is obtained with the initial state radiation (ISR) method using 232fb-1 of data collected with the BABAR detector at e+e- center-of-mass energies near 10.6 GeV. The ISR luminosity is determined from a study of the leptonic process e+e--->mu+mu-gamma(gamma). The leading-order hadronic

B. Aubert; Y. Karyotakis; J. P. Lees; V. Poireau; E. Prencipe; X. Prudent; V. Tisserand; J. Garra Tico; E. Grauges; M. Martinelli; A. Palano; M. Pappagallo; G. Eigen; B. Stugu; L. Sun; M. Battaglia; D. N. Brown; B. Hooberman; L. T. Kerth; Yu. G. Kolomensky; G. Lynch; I. L. Osipenkov; K. Tackmann; T. Tanabe; C. M. Hawkes; N. Soni; A. T. Watson; H. Koch; T. Schroeder; D. J. Asgeirsson; C. Hearty; T. S. Mattison; J. A. McKenna; M. Barrett; A. Khan; A. Randle-Conde; V. E. Blinov; A. D. Bukin; A. R. Buzykaev; V. P. Druzhinin; V. B. Golubev; A. P. Onuchin; S. I. Serednyakov; Yu. I. Skovpen; E. P. Solodov; K. Yu. Todyshev; M. Bondioli; S. Curry; I. Eschrich; D. Kirkby; A. J. Lankford; P. Lund; M. Mandelkern; E. C. Martin; D. P. Stoker; H. Atmacan; J. W. Gary; F. Liu; O. Long; G. M. Vitug; Z. Yasin; V. Sharma; C. Campagnari; T. M. Hong; D. Kovalskyi; M. A. Mazur; J. D. Richman; T. W. Beck; A. M. Eisner; C. A. Heusch; J. Kroseberg; W. S. Lockman; A. J. Martinez; T. Schalk; B. A. Schumm; A. Seiden; L. Wang; L. O. Winstrom; C. H. Cheng; D. A. Doll; B. Echenard; F. Fang; D. G. Hitlin; I. Narsky; P. Ongmongkolkul; T. Piatenko; F. C. Porter; R. Andreassen; G. Mancinelli; B. T. Meadows; K. Mishra; M. D. Sokoloff; P. C. Bloom; W. T. Ford; A. Gaz; J. F. Hirschauer; M. Nagel; U. Nauenberg; J. G. Smith; S. R. Wagner; R. Ayad; W. H. Toki; E. Feltresi; A. Hauke; H. Jasper; T. M. Karbach; J. Merkel; A. Petzold; B. Spaan; K. Wacker; M. J. Kobel; R. Nogowski; K. R. Schubert; R. Schwierz; D. Bernard; E. Latour; M. Verderi; P. J. Clark; S. Playfer; J. E. Watson; M. Andreotti; D. Bettoni; C. Bozzi; R. Calabrese; A. Cecchi; G. Cibinetto; E. Fioravanti; P. Franchini; E. Luppi; M. Munerato; M. Negrini; A. Petrella; L. Piemontese; V. Santoro; R. Baldini-Ferroli; A. Calcaterra; R. de Sangro; G. Finocchiaro; S. Pacetti; P. Patteri; I. M. Peruzzi; M. Piccolo; M. Rama; A. Zallo; R. Contri; E. Guido; M. Lo Vetere; M. R. Monge; S. Passaggio; C. Patrignani; E. Robutti; S. Tosi; M. Morii; A. Adametz; J. Marks; S. Schenk; U. Uwer; F. U. Bernlochner; H. M. Lacker; T. Lueck; A. Volk; P. D. Dauncey; M. Tibbetts; P. K. Behera; M. J. Charles; U. Mallik; J. Cochran; H. B. Crawley; L. Dong; V. Eyges; W. T. Meyer; S. Prell; E. I. Rosenberg; A. E. Rubin; Y. Y. Gao; A. V. Gritsan; Z. J. Guo; N. Arnaud; A. D'Orazio; M. Davier; D. Derkach; J. Firmino da Costa; G. Grosdidier; F. Le Diberder; V. Lepeltier; A. M. Lutz; B. Malaescu; P. Roudeau; M. H. Schune; J. Serrano; V. Sordini; A. Stocchi; G. Wormser; D. J. Lange; D. M. Wright; I. Bingham; J. P. Burke; C. A. Chavez; J. R. Fry; E. Gabathuler; R. Gamet; D. E. Hutchcroft; D. J. Payne; C. Touramanis; A. J. Bevan; C. K. Clarke; F. di Lodovico; R. Sacco; M. Sigamani; G. Cowan; S. Paramesvaran; A. C. Wren; C. L. Davis; M. Fritsch; W. Gradl; A. Hafner; K. E. Alwyn; D. Bailey; R. J. Barlow; G. Jackson; G. D. Lafferty; T. J. West; J. I. Yi; J. Anderson; C. Chen; A. Jawahery; D. A. Roberts; G. Simi; J. M. Tuggle; C. Dallapiccola; E. Salvati; R. Cowan; D. Dujmic; P. H. Fisher; S. W. Henderson; G. Sciolla; M. Spitznagel; R. K. Yamamoto; M. Zhao; P. M. Patel; S. H. Robertson; M. Schram; P. Biassoni; A. Lazzaro; V. Lombardo; F. Palombo; S. Stracka; L. Cremaldi; R. Godang; R. Kroeger; P. Sonnek; D. J. Summers; H. W. Zhao; X. Nguyen; M. Simard; P. Taras; H. Nicholson; G. de Nardo; L. Lista; D. Monorchio; G. Onorato; C. Sciacca; G. Raven; H. L. Snoek; C. P. Jessop; K. J. Knoepfel; J. M. Losecco; W. F. Wang; L. A. Corwin; K. Honscheid; H. Kagan; R. Kass; J. P. Morris; A. M. Rahimi; S. J. Sekula; N. L. Blount; J. Brau; R. Frey; O. Igonkina; J. A. Kolb; M. Lu; R. Rahmat; N. B. Sinev; D. Strom; J. Strube; E. Torrence; G. Castelli; N. Gagliardi; M. Margoni; M. Morandin; M. Posocco; M. Rotondo; F. Simonetto; R. Stroili; C. Voci; P. Del Amo Sanchez; E. Ben-Haim; G. R. Bonneaud; H. Briand; J. Chauveau; O. Hamon; Ph. Leruste; G. Marchiori; J. Ocariz; A. Perez; J. Prendki; S. Sitt; L. Gladney; M. Biasini; E. Manoni; C. Angelini; G. Batignani; S. Bettarini; G. Calderini; M. Carpinelli; A. Cervelli; F. Forti; M. A. Giorgi; A. Lusiani; M. Morganti; N. Neri; E. Paoloni; G. Rizzo; J. J. Walsh; D. Lopes Pegna; C. Lu; J. Olsen; A. J. S. Smith; A. V. Telnov; F. Anulli; E. Baracchini; G. Cavoto; R. Faccini; F. Ferrarotto; F. Ferroni; M. Gaspero; P. D. Jackson; L. Li Gioi; M. A. Mazzoni; S. Morganti; G. Piredda; F. Renga; C. Voena; M. Ebert; T. Hartmann; H. Schrder; R. Waldi; T. Adye; B. Franek; E. O. Olaiya; F. F. Wilson; S. Emery; L. Esteve; G. Hamel de Monchenault; W. Kozanecki; G. Vasseur; Ch. Yche; M. Zito; M. T. Allen; D. Aston; D. J. Bard; R. Bartoldus; J. F. Benitez; R. Cenci; J. P. Coleman; M. R. Convery; J. C. Dingfelder; J. Dorfan; G. P. Dubois-Felsmann; W. Dunwoodie; R. C. Field; M. Franco Sevilla; B. G. Fulsom; A. M. Gabareen; M. T. Graham; P. Grenier; C. Hast; W. R. Innes

2009-01-01

412

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

SciTech Connect

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

Al-Ghorabie, Fayez H.H. [Department of Physics, Faculty of Applied Sciences, Umm Al-Qura University, P.O. Box 10130, Makkah 21955 (Saudi Arabia)]. E-mail: alghorabie_f@hotmail.com

2005-06-01

413

Gamma  

NSDL National Science Digital Library

The Geometric Algorithms for Modeling, Motion, and Animation (GAMMA) research group is part of the Department of Computer Science at the University of North Carolina. Some of the topics of research include haptics, "robot motion planning," collision detection, and "real-time interaction with virtual environments." There are several projects that are described in detail for each of the main areas of investigation. Many recent papers are offered that describe the progress and findings of the group's research. Additionally, there is a large collection of videos demonstrating computer animation, simulation, and interactive applications. Some software can also be downloaded for the GAMMA Web site; however, access to a few of the titles must first be approved by the system administrator.

2007-07-28

414

Coffee-mediated protective effects against directly acting genotoxins and gamma-radiation in mouse lymphoma cells.  

PubMed

The cytokinesis-block micronucleus test was performed using L5178Y mouse lymphoma cells to ascertain whether or not standard (caffeinated) instant coffee, the commonly consumed polyphenolic beverage with antioxidant activity can protect against chromosomal damage induced by the directly acting agents N-methyl-N-nitro-N-nitrosoguanidine (MNNG), mitomycin C (MMC), methyl methanesulfonate (MMS) and gamma radiation. Our results demonstrated significant reductions in the in vitro genotoxic effects of MNNG, MMC, and MMS following co-treatment of mouse lymphoma cells with standard instant coffee. Subsequently, the comet assay was carried out to assess the effect of coffee co-treatment on the level of DNA damage induced by MMS in mouse lymphoma cells. The results demonstrated a significant reduction in MMS-induced DNA damage following co-treatment with standard instant coffee. Protective effects were observed in mouse lymphoma cells which were treated with coffee immediately after exposure to gamma radiation (1 and 2 Gy). Another experiment showed protection when the mammalian cells were irradiated (0.5 and 1 Gy) midway (at 2 h) during a 4 h coffee treatment. However, the protective effect against the lower dose (0.5 Gy) was not significant. In addition we assessed the modulatory effect of coffee on MNNG-induced apoptotic frequency by flow cytometry. The results revealed only a minor influence of coffee on the frequency of apoptotic cells induced by the test compounds, rendering an increase in sensitivity for apoptosis as a reason for the reduced genomic damage an unlikely or at least incomplete explanation. PMID:15242187

Abraham, S K; Vukicevic, V; Stopper, H

2004-03-01

415

Determination of radiative neutron capture cross sections for unstable nuclei by the {gamma}-ray strength function method  

SciTech Connect

An indirect method referred to as the {gamma}-ray strength function method has been devised to determine radiative neutron capture cross sections for unstable nuclei along the valley of {beta}-stability. This method is based on the {gamma}-ray strength function which interconnects radiative neutron capture and photoneutron emission within the statistical model. The method was applied to several unstable nuclei such as {sup 93,95}Zr, {sup 107}Pd, and 121,123Sn. This method offers a versatile application extended to unstable nuclei far from the stability when combined with Coulomb dissociation experiments at RIKEN-RIBF and GSI.

Utsunomiya, H.; Goriely, S. [Department of Physics, Konan University, Okamoto 8-9-1, Higashinada, Kobe 658-8501 (Japan); Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, Campus de la Plaine, CP-226, 1050 Brussels (Belgium)

2012-11-12

416

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

PubMed

The radon (Rn)-daughter level (track film, 3 months) was lower in 129 urban than in 197 rural houses (geometric means, (GM) 18 versus 40 Bq/m3; P < 0.001; range 3-416). In rural dwellings higher levels were found in those built over deposits of alum shale occurrences (P = 0.04; 12 on porous glaciofluvial cover 94 Bq/m3; 127 others 43 Bq/m3; significant interaction, P = 0.01), than in 158 others (37 Bq/m3). There was no systematic effect of the type of water supply, neither of indoor smoking. One hundred twenty three homes with a complete cellar were lower than 200 with no or part cellar (18 versus 40 Bq/m3; P < 0.001). There was only a weak association between log-transformed gamma radiation (GM 10, range 33-50 microR/h) and Rn-daughter levels (r = 0.18; 95% confidence interval 0.07-0.28). Our results show the importance for indoor Rn-daughter levels of the bedrock and cover beneath the house, and the need for Rn-daughter measurements in epidemiological studies. PMID:8424158

Tell, I; Jnsson, G; Bensryd, I; Attewell, R; Skerfving, S; Strmberg, U

1993-01-29

417

Radiation exposure levels within timber industries in Calabar, Nigeria  

PubMed Central

The UNSCEAR (2000) observed that there could be some exposure at work which would require regulatory control but is not really considered. This study was, therefore, set up to evaluate the effective dose in timber industries in Calabar, Nigeria to determine if the evaluated dose levels could lead to any radiological health effect in the workers, and also determine if the industries require regulatory control. The gamma ray exposure at four timber industries measured using an exposure meter were converted to effective dose and compared with the public and occupational values. The evaluated effective dose values in the timber industries were below public and occupational exposure limits and may not necessarily result in any radiological health hazard. Therefore, they may not require regulatory control.

Inyang, S. O.; Inyang, I. S.; Egbe, N. O.

2009-01-01

418

3D position of radiation sources using an automated gamma camera and ML algorithm with energy-dependent response functions  

NASA Astrophysics Data System (ADS)

Portable ?-ray imaging systems operating from 100keV to 3MeV are used in nuclear medicine, astrophysics and industrial applications. 2D images of ?-rays are common in many fields using radiation-detection systems (Appl. Opt. 17 (3) (1978) 337; IEEE Trans. Nucl. Sci. Ns- 31 (1984) 771; IEEE Trans. Nucl. Sci. NS- 44 (3) (1997) 911). In this work, the 3D position of a radiation source is determined by a portable gamma-ray imaging system. 2D gamma-ray images were obtained from different positions of the gamma camera and the third dimension, the distance between the detector and the radiation source, was calculated using triangulation. The imaging system consists of a 44 array of CsI(Tl) detectors coupled to photodiode detectors that are mounted on an automated table which can precisely position the angular axis of the camera. Lead shields the detector array from the background radiation. Additionally, a CCD camera is attached to the top of the gamma camera and provides coincident 2D visual information. The inferred distances from the center of the two measurement points and a radiation source had less than a 3% error within a range of 3m. The radiation image from the gamma camera and the visual image from CCD camera are superimposed into one combined image using a maximum-likelihood (ML) algorithm to make the image more precise. The response functions for the ML algorithm depend on the energy of incident radiation, and are obtained from both experiments and simulations. The energy-dependent response functions are shown to yield better imaging performance compared with the fixed energy response function commonly used previously.

Lee, Wonho; Wehe, David

2004-09-01

419

Study of biological effects of varying mixtures of Cf252 and gamma radiation on the acute radiation syndromes: Relevance to clinical radiotherapy of radioresistant cancer  

Microsoft Academic Search

Data for the 30 day bone marrow syndrome (BM-50) and the 6-10 day gastrointestinal (GI-50) syndrome for a one and two fraction schedule and acute and low dose rate irradiation using pure and mixed Cf-252 and photon radiation are presented. The radiation of Cf-252 is a mixture of neutrons and gamma rays. Balb\\/c mice of both sexes were total body

Yosh Maruyama; J. Wierzbicki; J. M. Feola

1993-01-01

420

Issues in the control of low-level radiation exposure.  

PubMed

The carcinogenic risks of exposure to low level ionizing radiation used by the International Commission on Radiation Protection (ICRP) have been challenged as being, at the same time, both too high and too low. This paper explains that the epidemiological evidence will always be limited at low doses, so that understanding the cellular mechanisms of carcinogenesis is increasingly important to assess the biological risks. An analysis is then given of the reasons why the challenges to ICRP, especially about the linear non-threshold response model, have arisen. As a result of considering the issues, the Main Commission of ICRP is now consulting on a revised, simpler, approach based on an individual oriented philosophy. This represents a potential shift by the Commission from the past emphasis on societal-oriented criteria. These proposals have been promulgated through the International Radiation Protection Association (IRPA) and an open literature publication was published in the Journal of Radiological Protection' in June 1999. On the basis of comments received and the observations presented at the IRPA 10 Conference, the Commission will begin to develop the outline of the next Recommendations. It is now more than ten years since ICRP distributed, for comment, a draft of what was to become the publication of the 1990 Recommendations. The Commission plans to develop its new Recommendations on a time scale of the next four or five years. In this paper, many of the issues that will need to be addressed in the development of the recommendations will be identified. These issues will cover biological effects, dosimetric quantities and the establishment of those levels of dose at which different protection requirements will be put into place. Concepts of exclusion and exemption will need to be clarified as well as the meaning of how to achieve what the proposal identifies as 'As Low as Reasonably Practicable' (ALARP). Finally, the Commission has decided to develop an environmental radiation protection philosophy that will need to be developed as part of the new Recommendations. PMID:11130633

Clarke, R H

421

Measurement of Branching Fractions in Radiative BDecays to eta K gamma and Search for B Decays to eta' K gamma  

SciTech Connect

The authors present measurements of the B {yields} {eta}K{gamma} branching fractions and upper limits for the B {yields} {eta}'K{gamma} branching fractions. For B{sup +} {yields} {eta}K{sup +}{gamma} they also measure the time-integrated charge asymmetry. The data sample, collected with the BABAR detector at the Stanford Linear Accelerator Center, represents 232 x 10{sup 6} produced B{bar B} pairs. The results for branching fractions and upper limits at 90% C.L. in units of 10{sup -6} are: {Beta}(B{sup 0} {yields} {eta}K{sup 0}{gamma}) = 11.3{sub -2.6}{sup +2.8} {+-} 0.6, {Beta}(B{sup +} {yields} {eta}K{sup +}{gamma}) = 10.0 {+-} 1.3 {+-} 0.5, {Beta}(B{sup 0} {yields} {eta}'K{sup 0}{gamma}) < 6.6, {Beta}(B{sup +} {yields} {eta}'K{sup +}{gamma}) < 4.2. The charge asymmetry in the decay B{sup +} {yields} {eta}K{sup +}{gamma} is {Alpha}{sub ch} = -0.09 {+-} 0.12 {+-} 0.01. The first errors are statistical and the second systematic.

Aubert, B.

2006-03-31

422

Energy levels and radiative rates for transitions in Ti VI  

NASA Astrophysics Data System (ADS)

Energies for 568 levels among the n=3+3p^64l+3s3p^54l configurations of Ti VI are calculated using the GRASP (General-purpose Relativistic Atomic Structure Program) code, which is based on the multi-configuration Dirac-Fock (MCDF) method. Additionally, radiative rates are calculated for all types of transitions, namely electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2). Lifetimes are also calculated for all the levels and extensive comparisons are made with the earlier available data as well as with other parallel calculations from the FAC (Flexible Atomic Code). Discrepancies for several levels with the earlier calculations of Mohan et al, (ADNDT 93 105 (2007)) are highlighted.

Aggarwal, Kanti; Keenan, Francis; Msezane, Alfred Z.

2012-06-01

423

Low-level gamma-ray spectrometry for analysing fusion plasma conditions  

NASA Astrophysics Data System (ADS)

A new method, combining activation by neutrons and charged particles with ultra low-level gamma-ray spectrometry, aimed at obtaining a better understanding and more adequate measurements of MeV particle leaks in magnetic fusion devices was studied here. A total of 36 samples containing Ti, LiF, B4C and W were placed in a boron-nitride holder mounted on the ceiling of the JET Tokamak. The samples were activated by 63 pulses from a D 3He plasma and were later measured using underground gamma-ray spectrometry. The radionuclides 7Be, 46Sc, 54Mn, 56Co, 57Co, 58Co, 124Sb, 181Hf, 182Ta, 181W and 185W were detected in several of the samples, with very low levels of activity of 47Sc and 48V found in a few of the samples. The various production channels for the radionuclides in question are discussed.

Wieslander, J. S. Elisabeth; Hult, Mikael; Bonheure, Georges; Arnold, Dirk; Dombrowski, Harald; Gasparro, Jol; Laubenstein, Matthias; Marissens, Gerd; Vermaercke, Peter

2008-06-01

424

Elimination of radiation-induced {gamma}-H2AX foci in mammalian nucleus can occur by histone exchange  

SciTech Connect

Double-strand breaks in mammalian DNA lead to rapid phosphorylation of C-terminal serines in histone H2AX ({gamma}-H2AX) and formation of large nuclear {gamma}-H2AX foci. After DNA repair these foci disappear, but molecular mechanism of elimination of {gamma}-H2AX foci remains unclear. H2AX protein can be phosphorylated and dephosphorylated in vitro in the absence of chromatin. Here, we compared global exchange of GFP-H2AX with kinetics of formation and elimination of radiation-induced {gamma}-H2AX foci. Maximal number of {gamma}-H2AX foci is observed one hour after irradiation, when {approx}20% of GFP-H2AX is exchanged suggesting that formation of the foci mostly occurs by in situ H2AX phosphorylation. However, slow elimination of {gamma}-H2AX foci is weakly affected by an inhibitor of protein phosphatases calyculin A which is known as an agent suppressing dephosphorylation of {gamma}-H2AX. This indicates that elimination of {gamma}-H2AX foci may be independent of dephosphorylation of H2AX which can occur after its removal from the foci by exchange.

Svetlova, Maria [Institute of Cytology RAS, 194064 St. Petersburg (Russian Federation); Solovjeva, Liudmila [Institute of Cytology RAS, 194064 St. Petersburg (Russian Federation); Nishi, Kayoko [Department of Biochemistry and Molecular Medicine, University of California Medical School, Davis, CA 95616 (United States); Nazarov, Igor [Department of Biochemistry and Molecular Medicine, University of California Medical School, Davis, CA 95616 (United States); Siino, Joseph [Department of Microbiology, University of California, Davis, CA 95616 (United States); Tomilin, Nikolai [Institute of Cytology RAS, 194064 St. Petersburg (Russian Federation)]. E-mail: nvtom@mail.ru

2007-06-29

425

Measuring Neutrons and Gamma Rays on Mars - The Mars Science Laboratory Radiation Assessment Detector MSL/RAD  

NASA Astrophysics Data System (ADS)

The Mars Science Laboratory (MSL) missions Radiation Assessment Detector (RAD) will measure the radiation environment on the Martian surface. One of the difficult measurements is that of the neutral radiation component consisting of neutrons and gamma rays. Different from Earth, this neutral component contributes substantially to the total dose on the planetary surface, principally because the Martian atmosphere is so thin. We will present methods to invert neutral particle data acquired with MSL's RAD instrument and compare them with calibration data. While the agreement is good for neutrons from a calibration beam in a forward model, more work is required for omnidirectional neutrons with unknown spectral properties using other inversion techniques. We expect an asymmetry in fluxes from soil and sky for neutrons. Preliminary simulation results show a different behavior for gamma rays. Therefore, models of the IRF are likely to require additional inputs about the radiation environement.

Martin, Cesar; Kortmann, Onno; Boehm, Eckart; Boettcher, Stephan; Kharytonov, Alexander; Ehresmann, Bent; Wimmer-Schweingruber, Robert F.; Hassler, Donald M.; Zeitlin, Cary

2010-05-01

426

MODELING SPECTRAL VARIABILITY OF PROMPT GAMMA-RAY BURST EMISSION WITHIN THE JITTER RADIATION PARADIGM  

SciTech Connect

The origin of rapid spectral variability and certain spectral correlations of prompt gamma-ray burst emission remains an intriguing question. The recently proposed theoretical model of the prompt emission is built upon unique spectral properties of jitter radiation-the radiation from small-scale magnetic fields generated at a site of strong energy release (e.g., a relativistic collisionless shock in baryonic or pair-dominated ejecta, or a reconnection site in a magnetically dominated outflow). Here we present the results of implementation of the model. We show that anisotropy of the jitter radiation pattern and relativistic shell kinematics altogether produce effects commonly observed in time-resolved spectra of the prompt emission, e.g., the softening of the spectrum below the peak energy within individual pulses in the prompt light curve, the so-called 'tracking' behavior (correlation of the observed flux with other spectral parameters), the emergence of hard, synchrotron-violating spectra at the beginning of individual spikes. Several observational predictions of the model are discussed.

Medvedev, Mikhail V.; Pothapragada, Sriharsha S.; Reynolds, Sarah J. [Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045 (United States)

2009-09-01

427

Relation among alcohol dehydrogenase 2 polymorphism, alcohol consumption, and levels of gamma-glutamyltransferase  

Microsoft Academic Search

In human beings, alcohol is metabolized primarily by alcohol dehydrogenase 2 (ADH2) and acetaldehyde dehydrogenase 2 (ALDH2). Whereas polymorphisms of the ALDH2 are common in Asian persons, polymorphisms of the ADH2 seem to be more important in Caucasian individuals. The aim of this study was to assess the relation among ADH2 polymorphism, alcohol consumption, and levels of gamma-glutamyltransferase (GGT). The

Michael Loew; Heiner Boeing; Til Strmer; Hermann Brenner

2003-01-01

428

Low-level gamma-ray spectrometry using Ge-detectors  

Microsoft Academic Search

The technological advances that have taken place during the past 45 years in the fabrication of high purity germanium crystals have had a significant impact on low-level gamma-ray spectrometry. Today, Ge-detectors with high purity Ge-crystals of 2 kg are readily available and detectors with crystals up to 5 kg can be produced. Use of large area crystals results in high

Mikael Hult

2007-01-01

429

Low-level gamma-ray spectrometry for analysing fusion plasma conditions  

Microsoft Academic Search

A new method, combining activation by neutrons and charged particles with ultra low-level gamma-ray spectrometry, aimed at obtaining a better understanding and more adequate measurements of MeV particle leaks in magnetic fusion devices was studied here. A total of 36 samples containing Ti, LiF, B4C and W were placed in a boron-nitride holder mounted on the ceiling of the JET

J. S. Elisabeth Wieslander; Mikael Hult; Georges Bonheure; Dirk Arnold; Harald Dombrowski; Jol Gasparro; Matthias Laubenstein; Gerd Marissens; Peter Vermaercke

2008-01-01

430

Determination of 137Cs in Soil Samples by Low-Level Compton Suppression Gamma-Counting  

Microsoft Academic Search

We have used Compton suppression gamma ray counting to effectively measure 137Cs in undisturbed environmental samples weighing only one hundred grams of material. Our results have shown that Compton suppression is ideal in determining low levels (13 Bq\\/kg) of 137Cs in soil samples, while the Compton advantage is negligible for higher concentrations. Quality assurance and quality control experiments show that

F. Y. Iskander; S. Landsberger; S. D. Warren

2000-01-01

431

Numerical study of Gamma-Ray Bursts: Relativistic radiation hydrodynamics simulation  

NASA Astrophysics Data System (ADS)

Special relativistic physics plays an important role in many celestial phenomena such as Gamma-Ray Bursts (GRBs) and Active Galactic Nuclei (AGNs). During the past decade, many efforts have been made to simulate these phenomena by developing relativistic hydrodynamics codes with various algorithms. A realistic simulation needs to include magnetic field and radiation which makes the computational code more complicated. For my thesis res