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Sample records for radiation environment nre

  1. Organization and operation of the Sixth International Symposium on the Natural Radiation Environment (NRE VI)

    Energy Technology Data Exchange (ETDEWEB)

    Hopke, P.K.

    1996-10-01

    An important source of human exposure to radiation is the natural world including cosmic rays, cosmogenic radionuclides, natural terrestrial radionuclides, and radon isotopes and its decay products. Considerable effort is being expended on a worldwide basis to characterize the exposure to the natural radiation environment and determine the important pathways for the exposure to result in the dose to tissue that leads to injury and disease. The problem of background exposure to naturally occurring radioactivity has been the subject of research since the initial discovery of the radioactivity of uranium and thorium. However, with the advent of artificial sources of radiation with both benefits and harm the nature and magnitude of the natural radiation environment and the effects on various populations are important in the development of overall public health strategies as ALARA principles are applied to the situation.

  2. Organization and operation of the sixth international symposium on the natural radiation environment (NRE VI). Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hopke, P.K.

    1995-12-31

    An important source of human exposure to radiation is the natural world including cosmic rays, cosmogonic radionuclides, natural terrestrial radionuclides, and radon isotopes and its decay products. Considerable effort is being expended on a worldwide basis to characterize the exposure to the natural radiation environment and determine the important pathways for the exposure to result in dose to tissue that leads to injury and disease. The problem of background exposure to naturally occurring radioactivity has been the subject of research since the initial discovery of the radioactivity of uranium and thorium. However, with the advent of artificial sources of radiation with both benefits (medical x-rays and nuclear medicine), and harm (Chernobyl fallout), the nature and magnitude of the natural radiation environment and the effects on various populations are important in the development of overall public health strategies as ALARA principles are applied. To facilitate the exchange of information and the review of uncertainties and scientific research priorities, a series of 5 international meetings on Natural Radiation Environment, 1963, 1987, 1991. This conference (Montreal, 1995) covers the range of natural radiation environments that give rise to human exposure and dose. This document is a program summary.

  3. Genesis Radiation Environment

    Science.gov (United States)

    Minow, Joseph I.; Altstatt, Richard L.; Skipworth, William C.

    2007-01-01

    The Genesis spacecraft launched on 8 August 2001 sampled solar wind environments at L1 from 2001 to 2004. After the Science Capsule door was opened, numerous foils and samples were exposed to the various solar wind environments during periods including slow solar wind from the streamer belts, fast solar wind flows from coronal holes, and coronal mass ejections. The Survey and Examination of Eroded Returned Surfaces (SEERS) program led by NASA's Space Environments and Effects program had initiated access for the space materials community to the remaining Science Capsule hardware after the science samples had been removed for evaluation of materials exposure to the space environment. This presentation will describe the process used to generate a reference radiation Genesis Radiation Environment developed for the SEERS program for use by the materials science community in their analyses of the Genesis hardware.

  4. Lunar radiation environment

    Science.gov (United States)

    Schwadron, Nathan; Spence, Harlan; Wilson, Jody

    One of the goals of the CRaTER investigation is to characterize the radiation environment near the Moon in order to enable exploration. The state-of-the-art understanding developed thus far during the LRO mission is documented in a special issue of the Spaceweather Journal entitled “Space Weather: Building the observational foundation to deduce biological effects of space radiation” (Schwadron et al., 2013a). This recently published CRaTER work probes deeper into the physics of the radiation environment at the Moon. It motivates and provides the scientific basis for new investigations in the next phase of the LRO mission. The effects of Galactic Cosmic Rays (GCRs) and Solar Energetic Particles (SEPs) range from chemical modification of the regolith, the generation of a radiation albedo that is increasingly illuminating chemical properties of the regolith, causing charging of the regolith and hazards to human explorers and robotic missions. Low-lunar orbit provides a platform for measuring SEP anisotropy over timescales of 2 hours both parallel and perpendicular to the ecliptic plane, and so far we have observed more than 18 SEP events with time-variable anisotropies during the LRO mission. Albedo proton maps of the Moon from CRaTER indicate that the flux of lunar albedo protons is correlated with elemental abundances at the lunar surface. The yield of albedo protons from the maria is 1% higher than the yield from the highlands, and there are localized peaks with even higher contrast (that may be co-located with peaks in trace elemental abundances as measured by the Lunar Prospector Gamma Ray Spectrometer). The Moon’s radiation environment both charges and affects the chemistry in the Moon’s polar regions, particularly in PSRs. This makes these regions a prime target for new CRaTER observations, since CRaTER measures GCRs and SEPs that penetrate the regolith down to 10s of cm. Thus, we review emerging discoveries from LRO/CRaTER’s remarkable exploration of

  5. Space Flight Ionizing Radiation Environments

    Science.gov (United States)

    Koontz, Steve

    2017-01-01

    The space-flight ionizing radiation (IR) environment is dominated by very high-kinetic energy-charged particles with relatively smaller contributions from X-rays and gamma rays. The Earth's surface IR environment is not dominated by the natural radioisotope decay processes. Dr. Steven Koontz's lecture will provide a solid foundation in the basic engineering physics of space radiation environments, beginning with the space radiation environment on the International Space Station and moving outward through the Van Allen belts to cislunar space. The benefits and limitations of radiation shielding materials will also be summarized.

  6. The space radiation environment

    Energy Technology Data Exchange (ETDEWEB)

    Robbins, D.E.

    1997-04-30

    There are three primary sources of space radiation: galactic cosmic rays (GCR), trapped belt radiation, and solar particle events (SPE). All are composed of ions, the nuclei of atoms. Their energies range from a few MeV u{sup -1} to over a GeV u{sup -1}. These ions can fragment when they interact with spacecraft materials and produce energetic neutrons and ions of lower atomic mass. Absorbed dose rates inside a typical spacecraft (like the Space Shuttle) in a low inclination (28.5 degrees) orbit range between 0.05 and 2 mGy d{sup -1} depending on the altitude and flight inclination (angle of orbit with the equator). The quality factor of radiation in orbit depends on the relative contributions of trapped belt radiation and GCR, and the dose rate varies both with orbital altitude and inclination. The corresponding equivalent dose rate ranges between 0.1 and 4 mSv d{sup -1}. In high inclination orbits, like that of the Mir Space Station and as is planned for the International Space Station, blood-forming organ (BFO) equivalent dose rates as high as 1.5 mSv d{sup -1}. Thus, on a 1 y mission, a crew member could obtain a total dose of 0.55 Sv. Maximum equivalent dose rates measured in high altitude passes through the South Atlantic Anomaly (SAA) were 10 mSv h{sup -1}. For an interplanetary space mission (e.g., to Mars) annual doses from GCR alone range between 150 mSv y{sup -1} at solar maximum and 580 mSv y{sup -1} at solar minimum. Large SPE, like the October 1989 series, are more apt to occur in the years around solar maximum. In free space, such an event could contribute another 300 mSv, assuming that a warning system and safe haven can be effectively used with operational procedures to minimize crew exposures. Thus, the total dose for a 3 y mission to Mars could exceed 2 Sv.

  7. PABLM. Accumulated Environment Radiation Dose

    Energy Technology Data Exchange (ETDEWEB)

    Napier, B.A.; Kennedy, W.E.Jr.; Soldat, J.K. [Pacific Northwest Lab., Richland, WA (United States)

    1981-04-01

    PABLM calculates internal radiation doses to man from radionuclides in food products and external radiation doses from radionuclides in the environment. Radiation doses from radionuclides in the environment may be calculated from deposition on the soil or plants during an atmospheric or liquid release, or from exposure to residual radionuclides after the releases have ended. Radioactive decay is considered during the release, after deposition, and during holdup of food after harvest. The radiation dose models consider exposure to radionuclides deposited on the ground or crops from contaminated air or irrigation water, radionuclides in contaminated drinking water, aquatic foods raised in contaminated water, and radionuclides in bodies of water and sediments where people might fish, boat, or swim. For vegetation, the radiation dose model considers both direct deposition and uptake through roots. Doses may be calculated for either a maximum-exposed individual or for a population group. The program is designed to calculate accumulated radiation doses from the chronic ingestion of food products that contain radionuclides and doses from the external exposure to radionuclides in the environment. A first-year committed dose is calculated as well as an integrated dose for a selected number of years.

  8. Radiation effects in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Begay, F.; Rosen, L.; Petersen, D.F.; Mason, C.; Travis, B. [Los Alamos National Lab., NM (United States); Yazzie, A. [Navajo Nation, Window Rock, AZ (United States). Dept. of History; Isaac, M.C.P.; Seaborg, G.T. [Lawrence Berkeley National Lab., CA (United States); Leavitt, C.P. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Physics and Astronomy

    1999-04-01

    Although the Navajo possess substantial resource wealth-coal, gas, uranium, water-this potential wealth has been translated into limited permanent economic or political power. In fact, wealth or potential for wealth has often made the Navajo the victims of more powerful interests greedy for the assets under limited Navajo control. The primary focus for this education workshop on the radiation effects in the environment is to provide a forum where scientists from the nuclear science and technology community can share their knowledge toward the advancement and diffusion of nuclear science and technology issues for the Navajo public. The scientists will make an attempt to consider the following basic questions; what is science; what is mathematics; what is nuclear radiation? Seven papers are included in this report: Navajo view of radiation; Nuclear energy, national security and international stability; ABC`s of nuclear science; Nuclear medicine: 100 years in the making; Radon in the environment; Bicarbonate leaching of uranium; and Computational methods for subsurface flow and transport. The proceedings of this workshop will be used as a valuable reference materials in future workshops and K-14 classrooms in Navajo communities that need to improve basic understanding of nuclear science and technology issues. Results of the Begay-Stevens research has revealed the existence of strange and mysterious concepts in the Navajo Language of nature. With these research results Begay and Stevens prepared a lecture entitled The Physics of Laser Fusion in the Navajo language. This lecture has been delivered in numerous Navajo schools, and in universities and colleges in the US, Canada, and Alaska.

  9. Galactic cosmic radiation environment models

    Science.gov (United States)

    Badhwar, G. D.; O'Neill, P. M.; Troung, A. G.

    2001-02-01

    Models of the radiation environment in free space and in near earth orbits are required to estimate the radiation dose to the astronauts for Mars, Space Shuttle, and the International Space Station missions, and to estimate the rate of single event upsets and latch-ups in electronic devices. Accurate knowledge of the environment is critical for the design of optimal shielding during both the cruise phase and for a habitat on Mars or the Moon. Measurements of the energy spectra of galactic cosmic rays (GCR) have been made for nearly four decades. In the last decade, models have been constructed that can predict the energy spectra of any GCR nuclei to an accuracy of better than 25%. Fresh and more accurate measurements have been made in the last year. These measurements can lead to more accurate models. Improvements in these models can be made in determining the local interstellar spectra and in predicting the level of solar modulation. It is the coupling of the two that defines a GCR model. This paper reviews of two of the more widely used models, and a comparison of their predictions with new proton and helium data from the Alpha Magnetic Spectrometer (AMS), and spectra of beryllium to iron in the ~40 to 500 MeV/n acquired by the Advanced Composition Explorer (ACE) during the 1997-98 solar minimum. Regressions equations relating the IMP-8 helium count rate to the solar modulation deceleration parameter calculated using the Climax neutron monitor rate have been developed and may lead to improvements in the predictive capacity of the models. .

  10. Overview of the Martian radiation environment experiment

    Energy Technology Data Exchange (ETDEWEB)

    Zeitlin, C.; Cleghorn, T.F.; Cucinotta, F.A.; Saganti, P.; Andersen, V.; Lee, K.T.; Pinsky, L.S.; Atwell, W.; Turner, R.; Badhwar, G.

    2004-12-01

    Space radiation presents a hazard to astronauts, particularly those journeying outside the protective influence of the geomagnetosphere. Crews on future missions to Mars will be exposed to the harsh radiation environment of deep space during the transit between Earth and Mars. Once on Mars, they will encounter radiation that is only slightly reduced, compared to free space, by the thin Martian atmosphere. NASA is obliged to minimize, where possible, the radiation exposures received by astronauts. Thus, as a precursor to eventual human exploration, it is necessary to measure the Martian radiation environment in detail. The MARIE experiment, aboard the 2001 Mars Odyssey spacecraft, is returning the first data that bear directly on this problem. Here we provide an overview of the experiment, including introductory material on space radiation and radiation dosimetry, a description of the detector, model predictions of the radiation environment at Mars, and preliminary dose-rate data obtained at Mars.

  11. Radiation Environment for the Jupiter Europa Orbiter

    Science.gov (United States)

    Jun, Insoo

    2008-09-01

    One of the major challenges for the Jupiter Europa Orbiter (JEO) mission would be that the spacecraft should be designed to survive an intense radiation environment expected at Jupiter and Europa. The proper definition of the radiation environments is the important first step, because it could affect almost every aspects of mission and spacecraft design. These include optimizing the trajectory to minimize radiation exposure, determining mission lifetime, selecting parts, materials, detectors and sensors, shielding design, etc. The radiation environments generated for the 2008 JEO study will be covered, emphasizing the radiation environment mainly responsible for the total ionizing dose (TID) and displacement damage dose (DDD). The latest models developed at JPL will be used to generate the TID and DDD environments. Finally, the major radiation issues will be summarized, and a mitigation plan will be discussed.

  12. Radiation Hardened Electronics for Extreme Environments

    Science.gov (United States)

    Keys, Andrew S.; Watson, Michael D.

    2007-01-01

    The Radiation Hardened Electronics for Space Environments (RHESE) project consists of a series of tasks designed to develop and mature a broad spectrum of radiation hardened and low temperature electronics technologies. Three approaches are being taken to address radiation hardening: improved material hardness, design techniques to improve radiation tolerance, and software methods to improve radiation tolerance. Within these approaches various technology products are being addressed including Field Programmable Gate Arrays (FPGA), Field Programmable Analog Arrays (FPAA), MEMS Serial Processors, Reconfigurable Processors, and Parallel Processors. In addition to radiation hardening, low temperature extremes are addressed with a focus on material and design approaches.

  13. Behaviour of organic materials in radiation environment

    CERN Document Server

    Tavlet, M

    2000-01-01

    Radiation effects in polymers are reminded together with the ageing factors. Radiation-ageing results are mainly discussed about thermosetting insulators, structural composites and cable-insulating materials. Some hints are given about high-voltage insulations, cooling fluids, organic scintillators and light-guides. Some parameters to be taken into account for the estimate of the lifetime of components in radiation environment are also shown. (23 refs).

  14. Natural radiation environment III. [Lead Abstract

    Energy Technology Data Exchange (ETDEWEB)

    Gesell, T.F.; Lowder, W.M. (eds.)

    1980-01-01

    Separate abstracts were prepared for the 52 research papers presented at this symposium in April 1978. The major topics in this volume deal with penetrating radiation measurements, radiation surveys and population exposure, radioactivity in the indoor environment, and technologically enhanced natural radioactivity. (KRM)

  15. The dynamic radiation environment assimilation model (DREAM)

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, Geoffrey D [Los Alamos National Laboratory; Koller, Josef [Los Alamos National Laboratory; Tokar, Robert L [Los Alamos National Laboratory; Chen, Yue [Los Alamos National Laboratory; Henderson, Michael G [Los Alamos National Laboratory; Friedel, Reiner H [Los Alamos National Laboratory

    2010-01-01

    The Dynamic Radiation Environment Assimilation Model (DREAM) is a 3-year effort sponsored by the US Department of Energy to provide global, retrospective, or real-time specification of the natural and potential nuclear radiation environments. The DREAM model uses Kalman filtering techniques that combine the strengths of new physical models of the radiation belts with electron observations from long-term satellite systems such as GPS and geosynchronous systems. DREAM includes a physics model for the production and long-term evolution of artificial radiation belts from high altitude nuclear explosions. DREAM has been validated against satellites in arbitrary orbits and consistently produces more accurate results than existing models. Tools for user-specific applications and graphical displays are in beta testing and a real-time version of DREAM has been in continuous operation since November 2009.

  16. The Radiation Environment of Exoplanet Atmospheres

    Directory of Open Access Journals (Sweden)

    Jeffrey L. Linsky

    2014-10-01

    Full Text Available Exoplanets are born and evolve in the radiation and particle environment created by their host star. The host star’s optical and infrared radiation heats the exoplanet’s lower atmosphere and surface, while the ultraviolet, extreme ultraviolet and X-radiation control the photochemistry and mass loss from the exoplanet’s upper atmosphere. Stellar radiation, especially at the shorter wavelengths, changes dramatically as a host star evolves leading to changes in the planet’s atmosphere and habitability. This paper reviews the present state of our knowledge concerning the time-dependent radiation emitted by stars with convective zones, that is stars with spectral types F, G, K, and M, which comprise nearly all of the host stars of detected exoplanets.

  17. NPS-SCAT CONOPS and Radiation Environment

    Science.gov (United States)

    2012-06-01

    interference with communication and other electronic hardware due to scintillation and wave refraction. The LEO plasma environment is at lower energy...effects include measurable changes in properties of semiconductors and a deterioration of the thermal radiation properties of materials due to the

  18. Radiation exposure in the moon environment

    Science.gov (United States)

    Reitz, Guenther; Berger, Thomas; Matthiae, Daniel

    2012-12-01

    During a stay on the moon humans are exposed to elevated radiation levels due to the lack of substantial atmospheric and magnetic shielding compared to the Earth's surface. The absence of magnetic and atmospheric shielding allows cosmic rays of all energies to impinge on the lunar surface. Beside the continuous exposure to galactic cosmic rays (GCR), which increases the risk of cancer mortality, exposure through particles emitted in sudden nonpredictable solar particle events (SPE) may occur. SPEs show an enormous variability in particle flux and energy spectra and have the potential to expose space crew to life threatening doses. On Earth, the contribution to the annual terrestrial dose of natural ionizing radiation of 2.4 mSv by cosmic radiation is about 1/6, whereas the annual exposure caused by GCR on the lunar surface is roughly 380 mSv (solar minimum) and 110 mSv (solar maximum). The analysis of worst case scenarios has indicated that SPE may lead to an exposure of about 1 Sv. The only efficient measure to reduce radiation exposure is the provision of radiation shelters. Measurements on the lunar surface performed during the Apollo missions cover only a small energy band for thermal neutrons and are not sufficient to estimate the exposure. Very recently some data were added by the Radiation Dose Monitoring (RADOM) instrument operated during the Indian Chandrayaan Mission and the Cosmic Ray Telescope (CRaTER) instrument of the NASA LRO (Lunar Reconnaisance Orbiter) mission. These measurements need to be complemented by surface measurements. Models and simulations that exist describe the approximate radiation exposure in space and on the lunar surface. The knowledge on the radiation exposure at the lunar surface is exclusively based on calculations applying radiation transport codes in combination with environmental models. Own calculations are presented using Monte-Carlo simulations to calculate the radiation environment on the moon and organ doses on the

  19. Radiation resistence of microorganisms from radiation sterilization processing environments

    Science.gov (United States)

    Sabovljev, Svetlana A.; Žunić, Zora S.

    The radiation resistance of microorganisms was examined on the samples of dust collected from the radiation sterilization processing environments including assembly, storage, and sterilization plant areas. The isolation of radiation resistant strains was performed by irradiation with screening doses ranging from 10 to 35 kGy and test pieces containing 10 6 to 10 8 CFU in dried serum-broth, representing 100 to 5000 colonies of primary cultures of microorganisms from 7 different sites. In an examination of 16900 colonies of aerobic microorganisms from 3 hygienically controlled production sites and 4 uncontrolled ones, 30 strains of bacteria were isolated. Of those 15 were classified as genus Bacillus, 9 as Micrococcus and 6 as Sarcina. All of the 15 strains of Gram positive sporeforming aerobic rods exhibited an exponential decrease in the surviving fraction as a function of dose, indicating that the inactivation of spores of aerobic rods is a consequence of a single energy deposition into the target. All strains were found to be moderately resistant to radiation with D-6 values (dose required to reduce survival to 6 log cycles) between 18 and 26 kGy. All of the isolated Gram positive cocci showed inactivation curves having a shoulder, indicating that different processes are involved in the inactivation of these cells, e.g. accumulation of sublethal lesions, or final repair capacity of potential lethal lesions. Moderate radiation resistance was observed in 13 strains with D-6 values between 16 to 30 kGy. Two slow-growing, red pigmented strains tentatively classified as genus Micrococcus isolated from uncontrolled sites (human dwellings) were exceptionally resistant with D-6 more than 45 kGy. For hygienically controlled sites, Gram positive spereforming rods composed two thirds of the resistant microflora, while Gram positive cocci comprised one third. For hygienically uncontrolled sites this ratio was reversed. An assumption is made that one isolated strain has grown

  20. Ionizing Radiation Environments and Exposure Risks

    Science.gov (United States)

    Kim, M. H. Y.

    2015-12-01

    Space radiation environments for historically large solar particle events (SPE) and galactic cosmic rays (GCR) are simulated to characterize exposures to radio-sensitive organs for missions to low-Earth orbit (LEO), moon, near-Earth asteroid, and Mars. Primary and secondary particles for SPE and GCR are transported through the respective atmospheres of Earth or Mars, space vehicle, and astronaut's body tissues using NASA's HZETRN/QMSFRG computer code. Space radiation protection methods, which are derived largely from ground-based methods recommended by the National Council on Radiation Protection and Measurements (NCRP) or International Commission on Radiological Protections (ICRP), are built on the principles of risk justification, limitation, and ALARA (as low as reasonably achievable). However, because of the large uncertainties in high charge and energy (HZE) particle radiobiology and the small population of space crews, NASA develops distinct methods to implement a space radiation protection program. For the fatal cancer risks, which have been considered the dominant risk for GCR, the NASA Space Cancer Risk (NSCR) model has been developed from recommendations by NCRP; and undergone external review by the National Research Council (NRC), NCRP, and through peer-review publications. The NSCR model uses GCR environmental models, particle transport codes describing the GCR modification by atomic and nuclear interactions in atmospheric shielding coupled with spacecraft and tissue shielding, and NASA-defined quality factors for solid cancer and leukemia risk estimates for HZE particles. By implementing the NSCR model, the exposure risks from various heliospheric conditions are assessed for the radiation environments for various-class mission types to understand architectures and strategies of human exploration missions and ultimately to contribute to the optimization of radiation safety and well-being of space crewmembers participating in long-term space missions.

  1. Radiation Effects in the Space Telecommunications Environment

    Energy Technology Data Exchange (ETDEWEB)

    Fleetwood, Daniel M.; Winokur, Peter S.

    1999-05-17

    Trapped protons and electrons in the Earth's radiation belts and cosmic rays present significant challenges for electronics that must operate reliably in the natural space environment. Single event effects (SEE) can lead to sudden device or system failure, and total dose effects can reduce the lifetime of a telecommmiications system with significant space assets. One of the greatest sources of uncertainty in developing radiation requirements for a space system is accounting for the small but finite probability that the system will be exposed to a massive solar particle event. Once specifications are decided, standard laboratory tests are available to predict the total dose response of MOS and bipolar components in space, but SEE testing of components can be more challenging. Prospects are discussed for device modeling and for the use of standard commercial electronics in space.

  2. CSIR eNews: Natural resources and environment

    CSIR Research Space (South Africa)

    CSIR

    2008-03-01

    Full Text Available The CSIR conducts core research and develops competencies in various strategically critical areas of the natural resources and the environment (NRE) fields of study. Through relevant and focused research, CSIR Natural Resources and the Environment...

  3. CSIR eNews: Natural resources and environment

    CSIR Research Space (South Africa)

    CSIR

    2007-12-01

    Full Text Available The CSIR conducts core research and develops competencies in various strategically critical areas of the natural resources and the environment (NRE) fields of study. Through relevant and focused research, CSIR Natural Resources and the Environment...

  4. High Radiation Environment Nuclear Fragment Separator Magnet

    Energy Technology Data Exchange (ETDEWEB)

    Kahn, Stephen [Muons, Inc., Batavia, IL (United States); Gupta, Ramesh [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-01-31

    Superconducting coils wound with HTS conductor can be used in magnets located in a high radiation environment. NbTi and Nb3Sn superconductors must operate at 4.5 K or below where removal of heat is less efficient. The HTS conductor can carry significant current at higher temperatures where the Carnot efficiency is significantly more favorable and where the coolant heat capacity is much larger. Using the HTS conductor the magnet can be operated at 40 K. This project examines the use of HTS conductor for the Michigan State University Facility For Rare Isotope Beams (FRIB) fragment separator dipole magnet which bends the beam by 30° and is located in a high radiation region that will not be easily accessible. Two of these magnets are needed to select the chosen isotope. There are a number of technical challenges to be addressed in the design of this magnet. The separator dipole is 2 m long and subtends a large angle. The magnet should keep a constant transverse field profile along its beam reference path. Winding coils with a curved inner segment is difficult as the conductor will tend to unwind during the process. In the Phase I project two approaches to winding the conductor were examined. The first was to wind the coils with curved sections on the inner and outer segments with the inner segment wound with negative curvature. The alternate approach was to use a straight segment on the inner segment to avoid negative curvature. In Phase I coils with a limited number of turns were successfully wound and tested at 77 K for both coil configurations. The Phase II program concentrated on the design, coil winding procedures, structural analysis, prototyping and testing of an HTS curved dipole coil at 40 K with a heat load representative of the radiation environment. One of the key criteria of the design of this magnet is to avoid the use of organic materials that would degrade rapidly in radiation. The Lorentz forces expected from the coils interacting with the

  5. Reliability of computer memories in radiation environment

    Directory of Open Access Journals (Sweden)

    Fetahović Irfan S.

    2016-01-01

    Full Text Available The aim of this paper is examining a radiation hardness of the magnetic (Toshiba MK4007 GAL and semiconductor (AT 27C010 EPROM and AT 28C010 EEPROM computer memories in the field of radiation. Magnetic memories have been examined in the field of neutron radiation, and semiconductor memories in the field of gamma radiation. The obtained results have shown a high radiation hardness of magnetic memories. On the other side, it has been shown that semiconductor memories are significantly more sensitive and a radiation can lead to an important damage of their functionality. [Projekat Ministarstva nauke Republike Srbije, br. 171007

  6. Geant4 models for space radiation environment.

    Science.gov (United States)

    Ivantchenko, Anton; Nieminen, Petteri; Incerti, Sebastien; Santin, Giovanni; Ivantchenko, Vladimir; Grichine, Vladimir; Allison, John

    The space radiation environment includes wide varieties of particles from electrons to heavy ions. In order to correctly predict the dose received by astronauts and devices the simulation models must have good applicability and produce accurate results from 10 MeV/u up to 10 GeV/u, where the most radioactive hazardous particles are present in the spectra. Appropriate models should also provide a good description of electromagnetic interactions down to very low energies (10 eV/u - 10 MeV/u) for understanding the damage mechanisms due to long-term low doses. Predictions of biological dose during long interplanetary journeys also need models for hadronic interactions of energetic heavy ions extending higher energies (10 GeV/u - 100 GeV/u, but possibly up to 1 TeV/u). Geant4 is a powerful toolkit, which in some areas well surpasses the needs from space radiation studies, while in other areas is being developed and/or validated to properly cover the modelling requirements outlined above. Our activities in ESA projects deal with the research and development of both Geant4 hadronic and electromagnetic physics. Recently the scope of verification tests and benchmarks has been extended. Hadronic tests and benchmarks run proton, pion, and ion interactions with matter at various energies. In the Geant4 hadronic sub-libraries, the most accurate cross sections have been identified and selected as a default for all particle types relevant to space applications. Significant developments were carried out for ion/ion interaction models. These now allow one to perform Geant4 simulations for all particle types and energies relevant to space applications. For the validation of ion models the hadronic testing suite for ion interactions was significantly extended. In this work the results of benchmarking versus data in a wide energy range for projectile protons and ions will be shown and discussed. Here we show results of the tests runs and their precision. Recommendations for Geant4

  7. Evaluation of the Radiation Environment of the LHCb Experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00341385; Corti, Gloria

    The unprecedented radiation levels of the Large Hadron Collider (LHC) during high-energy proton-proton collisions will have an impact on the operation of its experiments’ detectors and electronics. LHCb, one of the 4 major LHC experiments, has started operation in 2009 and from 2011 onward it has been collecting data at and above its design luminosity. Detectors and associated detector electronics are prone to damage if the radiation levels exceed the expected values. It is essential to monitor the radiation environment of the experimental area and compare it with predictions obtained from simulation studies in order to assess the situation and take corrective action in case of need. Understanding the existing radiation environment will also provide important input to the planning of maintenance and for operation at upgrade luminosity. A set of radiation detectors has been installed in the LHCb experimental area to measure different aspects of its radiation environment. Passive dosimeters including Thermo-L...

  8. A Comparative Study of Proteolytic Mechanisms during Leaf Senescence of Four Genotypes of Winter Oilseed Rape Highlighted Relevant Physiological and Molecular Traits for NRE Improvement

    Directory of Open Access Journals (Sweden)

    Alexandra Girondé

    2015-12-01

    Full Text Available Winter oilseed rape is characterized by a low N use efficiency related to a weak leaf N remobilization efficiency (NRE at vegetative stages. By investigating the natural genotypic variability of leaf NRE, our goal was to characterize the relevant physiological traits and the main protease classes associated with an efficient proteolysis and high leaf NRE in response to ample or restricted nitrate supply. The degradation rate of soluble proteins and D1 protein (a thylakoid-bound protein were correlated to N remobilization, except for the genotype Samouraï which showed a low NRE despite high levels of proteolysis. Under restricted nitrate conditions, high levels of soluble protein degradation were associated with serine, cysteine and aspartic proteases at acidic pH. Low leaf NRE was related to a weak proteolysis of both soluble and thylakoid-bound proteins. The results obtained on the genotype Samouraï suggest that the timing between the onset of proteolysis and abscission could be a determinant. The specific involvement of acidic proteases suggests that autophagy and/or senescence-associated vacuoles are implicated in N remobilization under low N conditions. The data revealed that the rate of D1 degradation could be a relevant indicator of leaf NRE and might be used as a tool for plant breeding.

  9. Emergency Medical Rescue in a Radiation Environment

    Energy Technology Data Exchange (ETDEWEB)

    Briesmeister, L.; Ellington, Y.; Hollis, R.; Kunzman, J.; McNaughton, M.; Ramsey, G.; Somers, B.; Turner, A.; Finn, J.

    1999-09-14

    Previous experience with emergency medical rescues in the presence of radiation or contamination indicates that the training provided to emergency responders is not always appropriate. A new course developed at Los Alamos includes specific procedures for emergency response in a variety of radiological conditions.

  10. Radiation Environments and their Impact at the CERN's Injector Chain

    CERN Document Server

    De Carvalho Saraiva, Joao Pedro; CERN. Geneva. ATS Department

    2015-01-01

    Mixed particle and energy radiation fields present at the Large Hadron Collider (LHC) and its Injector Chain are responsible for failures on electronic devices located in the vicinity of the accelerator beam lines. These radiation effects on electronics and, more generally, the overall radiation damage issues have a direct impact on component and system lifetimes, as well as on maintenance requirements and radiation exposure to personnel who have to intervene and fix the faults. This note describes the different radiation environments present along the CERN’s Injector Chain and the expected evolution over the next years with the ongoing LHC Injectors Upgrade (LIU) project. The available dosimetry and beam monitoring systems used to assess radiation levels are presented, outlining their respective pros and cons. The interplay between Monte Carlo simulations and the available radiation monitoring in the Injectors is also presented.

  11. Evaluations of Risks from the Lunar and Mars Radiation Environments

    Science.gov (United States)

    Kim, Myung-Hee; Hayat, Matthew J.; Feiveson, Alan H.; Cucinotta, Francis A.

    2008-01-01

    Protecting astronauts from the space radiation environments requires accurate projections of radiation in future space missions. Characterization of the ionizing radiation environment is challenging because the interplanetary plasma and radiation fields are modulated by solar disturbances and the radiation doses received by astronauts in interplanetary space are likewise influenced. The galactic cosmic radiation (GCR) flux for the next solar cycle was estimated as a function of interplanetary deceleration potential, which has been derived from GCR flux and Climax neutron monitor rate measurements over the last 4 decades. For the chaotic nature of solar particle event (SPE) occurrence, the mean frequency of SPE at any given proton fluence threshold during a defined mission duration was obtained from a Poisson process model using proton fluence measurements of SPEs during the past 5 solar cycles (19-23). Analytic energy spectra of 34 historically large SPEs were constructed over broad energy ranges extending to GeV. Using an integrated space radiation model (which includes the transport codes HZETRN [1] and BRYNTRN [2], and the quantum nuclear interaction model QMSFRG[3]), the propagation and interaction properties of the energetic nucleons through various media were predicted. Risk assessment from GCR and SPE was evaluated at the specific organs inside a typical spacecraft using CAM [4] model. The representative risk level at each event size and their standard deviation were obtained from the analysis of 34 SPEs. Risks from different event sizes and their frequency of occurrences in a specified mission period were evaluated for the concern of acute health effects especially during extra-vehicular activities (EVA). The results will be useful for the development of an integrated strategy of optimizing radiation protection on the lunar and Mars missions. Keywords: Space Radiation Environments; Galactic Cosmic Radiation; Solar Particle Event; Radiation Risk; Risk

  12. Designing Equipment for Use in Gamma Radiation Environments

    Energy Technology Data Exchange (ETDEWEB)

    Vandergriff, K.U.

    1990-01-01

    High levels of gamma radiation are known to cause degradation in a variety of materials and components. When designing systems to operate in a high radiation environment, special precautions and procedures should be followed. This report (1) outlines steps that should be followed in designing equipment and (2) explains the general effects of radiation on various engineering materials and components. Much information exists in the literature on radiation effects upon materials. However, very little information is available to give the designer a step-by-step process for designing systems that will be subject to high levels of gamma radiation, such as those found in a nuclear fuel reprocessing facility. In this report, many radiation effect references are relied upon to aid in the design of components and systems.

  13. Research on environment monitoring of radiation emergency

    CERN Document Server

    Ito, Y; Otani, N

    2003-01-01

    In a case of a nuclear accident at nuclear facilities, strong radiation such as g-rays and neutrons might radiate at a burst in the initial stage. For the establishment of dose estimation system for such accidents, the experiments were done using the He sup + sup 2 beam accelerated by Tandem in the W-MAST. The following results were obtained. 1) Neutron measurements using a rem counter yielded that dose equivalent was about 9.4 mSv/h at a position 100 cm from the Be target when the beam current of 15 MeV He sup 2 sup + was 0.8 mu A. Neutron measurement by means of Au and In foil activation method and by use of TLD element revealed that dose equivalents were to be 16-27 mu Sv/h for thermal neutron, and 30-41 mu Sv/h for sub-fast neutron (20 keV). Therefore, it was concluded that neutron field was mainly composed by fast neutron. 2) Linearity of the rem-counter out put vs neutron flux was valid under the condition that the count rate of the rem-counter was less than 10 kcps. 3) Computer simulation using NRESP c...

  14. Research on environment monitoring of radiation emergency

    CERN Document Server

    Ito, Y

    2002-01-01

    In a case of a nuclear accident at nuclear facilities, radiation such as gamma-rays and neutrons might radiate at a burst in the initial stage. For the establishment of dose estimation system for such accidents, the experiments were carried out using the Tandem/Synchrotron accelerator. The following results were obtained: (1) Measurements of the gamma-ray emission using the NaI detector together with pile up rejection system revealed that the good signals without the pile up phenomena could be obtained in case of count rate less than 7 kc/s. On assumption that energy distribution function of the gamma-rays was proportional to be E exp(- E/T sub e sub f sub f), the effective temperature T sub e sub f sub f was estimated to be 0.8 - 0.9 MeV by use of non-linear least squares. (2) Doses of gamma-rays were measured using the TLD elements shielded by Pb sheets with various widths. The effective temperature T sub e sub f sub f estimated under the same experimental conditions described in (1) was 0.6-3 MeV. In an ac...

  15. The development of advanced robotics technology in high radiation environment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Bum; Cho, Jaiwan; Lee, Nam Ho; Choi, Young Soo; Park, Soon Yong; Lee, Jong Min; Park, Jin Suk; Kim, Seung Ho; Kim, Byung Soo; Moon, Byung Soo

    1997-07-01

    In the tele-operation technology using tele-presence in high radiation environment, stereo vision target tracking by centroid method, vergence control of stereo camera by moving vector method, stereo observing system by correlation method, horizontal moving axis stereo camera, and 3 dimensional information acquisition by stereo image is developed. Also, gesture image acquisition by computer vision and construction of virtual environment for remote work in nuclear power plant. In the development of intelligent control and monitoring technology for tele-robot in hazardous environment, the characteristics and principle of robot operation. And, robot end-effector tracking algorithm by centroid method and neural network method are developed for the observation and survey in hazardous environment. 3-dimensional information acquisition algorithm by structured light is developed. In the development of radiation hardened sensor technology, radiation-hardened camera module is designed and tested. And radiation characteristics of electric components is robot system is evaluated. Also 2-dimensional radiation monitoring system is developed. These advanced critical robot technology and telepresence techniques developed in this project can be applied to nozzle-dam installation /removal robot system, can be used to realize unmanned remotelization of nozzle-dam installation / removal task in steam generator of nuclear power plant, which can be contributed for people involved in extremely hazardous high radioactivity area to eliminate their exposure to radiation, enhance their task safety, and raise their working efficiency. (author). 75 refs., 21 tabs., 15 figs.

  16. On the Radiation Protection of the Environment

    Energy Technology Data Exchange (ETDEWEB)

    Soberhart, L. J.; Clausse, A.; D' Amato, E.

    2004-07-01

    Over the last decade, substantial advances in what is know as legal protection of the environment, -as a different matter from human being protection- have been made. Some national legislations include serious penalties against environmental damage. It is becoming customary to consider a serious offence any excess in the prescribed limits of radioactive materials release to the environment. What these limits mean, however, is not completely clear nowadays. According to the International Commission on Radiological Protection (ICRP) the standards of environmental control needed to protect man to the degree currently thought desirable will ensure that other species are not put at risk, although, occasionally, individual members of non human species might be harmed. However the use of limits of radioactive releases resulting from the direct application of ICRP recommend limits as legal references for the applicable offences in environmental protection is certainly a misconception. In this paper a conceptual framework for the calculation of legal limits for environmental radioprotection are presented. The approach is based on an ecosystem perspective, assessing the impact of radioactive releases on the ecosystem dynamics and equilibrium. The method is based on functional groups models -i.e. groups of species that are selected from a number of criteria such as play similar rules in the chain of nutrients or have the same radiosensitivity- providing the basis for prescribed limits of the radioactive material release to the environment. The methodology is applied to a system of three functional groups in equilibrium, with is affected by radioactive intrusion. Different impacts on the equilibrium can be identified, depending on the amount of radioactive material released to the environment. It is shown how the concept of equilibrium breakdown can be applied in order to assess the radiological impact. (Author) 8 refs.

  17. Predictive aging results in radiation environments

    Science.gov (United States)

    Gillen, Kenneth T.; Clough, Roger L.

    1993-06-01

    We have previously derived a time-temperature-dose rate superposition methodology, which, when applicable, can be used to predict polymer degradation versus dose rate, temperature and exposure time. This methodology results in predictive capabilities at the low dose rates and long time periods appropriate, for instance, to ambient nuclear power plant environments. The methodology was successfully applied to several polymeric cable materials and then verified for two of the materials by comparisons of the model predictions with 12 year, low-dose-rate aging data on these materials from a nuclear environment. In this paper, we provide a more detailed discussion of the methodology and apply it to data obtained on a number of additional nuclear power plant cable insulation (a hypalon, a silicone rubber and two ethylene-tetrafluoroethylenes) and jacket (a hypalon) materials. We then show that the predicted, low-dose-rate results for our materials are in excellent agreement with long-term (7-9 year) low-dose-rate results recently obtained for the same material types actually aged under bnuclear power plant conditions. Based on a combination of the modelling and long-term results, we find indications of reasonably similar degradation responses among several different commercial formulations for each of the following "generic" materials: hypalon, ethylene-tetrafluoroethylene, silicone rubber and PVC. If such "generic" behavior can be further substantiated through modelling and long-term results on additional formulations, predictions of cable life for other commercial materials of the same generic types would be greatly facilitated.

  18. PABLM; accumulated environment radiation dose. [UNIVAC1100; FORTRAN

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, T.B.; Tobias, M.L.; Fox, J.N.; Lawler, B.E.; Koppel, J.U.; Triplett, J.R.; Lynn, L.L.; Waldman, L.A.; Goldberg, I.; Greebler, P.; Kelley, M.D.; Davis, R.A.; Keck, C.E.; Redfield, J.A.; Murphy,; Soldat, J.K.

    PABLM calculates internal radiation doses to man from radionuclides in food products and external radiation doses from radionuclides in the environment. Radiation doses from radionuclides in the environment may be calculated from deposition on the soil or plants during an atmospheric or liquid release, or from exposure to residual radionuclides after the releases have ended. Radioactive decay is considered during the release, after deposition, and during holdup of food after harvest. The radiation dose models consider exposure to radionuclides deposited on the ground or crops from contaminated air or irrigation water, radionuclides in contaminated drinking water, aquatic foods raised in contaminated water, and radionuclides in bodies of water and sediments where people might fish, boat, or swim. For vegetation, the radiation dose model considers both direct deposition and uptake through roots. Doses may be calculated for either a maximum-exposed individual or for a population group. The program is designed to calculate accumulated radiation doses from the chronic ingestion of food products that contain radionuclides and doses from the external exposure to radionuclides in the environment. A first-year committed dose is calculated as well as an integrated dose for a selected number of years.UNIVAC1100; FORTRAN; EXEC8; 80,000 words of memory are required to execute the PABLM program.

  19. Status Report of Simulated Space Radiation Environment Facility

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Phil Hyun; Nho, Young Chang; Jeun, Joon Pyo; Choi, Jae Hak; Lim, Youn Mook; Jung, Chan Hee; Jeon, Young Kyu

    2007-11-15

    The technology for performance testing and improvement of materials which are durable at space environment is a military related technology and veiled and securely regulated in advanced countries such as US and Russia. This core technology cannot be easily transferred to other country too. Therefore, this technology is the most fundamental and necessary research area for the successful establishment of space environment system. Since the task for evaluating the effects of space materials and components by space radiation plays important role in satellite lifetime extension and running failure percentage decrease, it is necessary to establish simulated space radiation facility and systematic testing procedure. This report has dealt with the status of the technology to enable the simulation of space environment effects, including the effect of space radiation on space materials. This information such as the fundamental knowledge of space environment and research status of various countries as to the simulation of space environment effects of space materials will be useful for the research on radiation hardiness of the materials. Furthermore, it will be helpful for developer of space material on deriving a better choice of materials, reducing the design cycle time, and improving safety.

  20. Contribution to developing the environment radiation protection methodology

    Energy Technology Data Exchange (ETDEWEB)

    Oudalova, A. [Institute of Atomic Power Engineering NRNU MEPhI (Russian Federation); Alexakhin, R.; Dubynina, M. [Russian Institute of Agricultural Radiology and Agroecology (Russian Federation)

    2014-07-01

    The environment sustainable development and biota protection, including the environment radiation protection are issues of nowadays interest in the society. An activity is ongoing on the development of a system of radiation protection for non-human biota. Anthropocentric and eco-centric principles are widely discussed. ICRP Publications 103, 108, 114 and many other reports and articles refer to the topic of environmental protection, reference animals and plants set, corresponding transfer parameters, dose models and derived consideration reference levels. There is still an open field for discussion of methods and approaches to get well-established procedure to assess environmental risks of radiation impacts to different organisms, populations and ecosystems. A huge work has been done by the ICRP and other organizations and research groups to develop and systematize approaches for this difficult subject. This activity, however, is not everywhere well-known and perceived, and more efforts are needed to bring ideas of eco-centric strategy in the environment radiation protection not only to public but to specialists in many countries as well. One of the main points of interest is an assessment of critical doses and doses rates for flora and fauna species. Some aspects of a possible procedure to find their estimates are studied in this work, including criteria for datasets of good quality, models of dose dependence, sensitivity of different umbrella endpoints and methods of original massive datasets treatment. Estimates are done based on information gathered in a database on radiation-induced effects in plants. Data on biological effects in plants (umbrella endpoints of reproductive potential, survival, morbidity, morphological, biochemical, and genetic effects) in dependence on dose and dose rates of ionizing radiation have been collected from reviewed publications and maintained in MS Access format. The database now contains about 7000 datasets and 25000 records

  1. Assessment of radiation awareness training in immersive virtual environments

    Science.gov (United States)

    Whisker, Vaughn E., III

    The prospect of new nuclear power plant orders in the near future and the graying of the current workforce create a need to train new personnel faster and better. Immersive virtual reality (VR) may offer a solution to the training challenge. VR technology presented in a CAVE Automatic Virtual Environment (CAVE) provides a high-fidelity, one-to-one scale environment where areas of the power plant can be recreated and virtual radiation environments can be simulated, making it possible to safely expose workers to virtual radiation in the context of the actual work environment. The use of virtual reality for training is supported by many educational theories; constructivism and discovery learning, in particular. Educational theory describes the importance of matching the training to the task. Plant access training and radiation worker training, common forms of training in the nuclear industry, rely on computer-based training methods in most cases, which effectively transfer declarative knowledge, but are poor at transferring skills. If an activity were to be added, the training would provide personnel with the opportunity to develop skills and apply their knowledge so they could be more effective when working in the radiation environment. An experiment was developed to test immersive virtual reality's suitability for training radiation awareness. Using a mixed methodology of quantitative and qualitative measures, the subjects' performances before and after training were assessed. First, subjects completed a pre-test to measure their knowledge prior to completing any training. Next they completed unsupervised computer-based training, which consisted of a PowerPoint presentation and a PDF document. After completing a brief orientation activity in the virtual environment, one group of participants received supplemental radiation awareness training in a simulated radiation environment presented in the CAVE, while a second group, the control group, moved directly to the

  2. ISS Radiation Shielding and Acoustic Simulation Using an Immersive Environment

    Science.gov (United States)

    Verhage, Joshua E.; Sandridge, Chris A.; Qualls, Garry D.; Rizzi, Stephen A.

    2002-01-01

    The International Space Station Environment Simulator (ISSES) is a virtual reality application that uses high-performance computing, graphics, and audio rendering to simulate the radiation and acoustic environments of the International Space Station (ISS). This CAVE application allows the user to maneuver to different locations inside or outside of the ISS and interactively compute and display the radiation dose at a point. The directional dose data is displayed as a color-mapped sphere that indicates the relative levels of radiation from all directions about the center of the sphere. The noise environment is rendered in real time over headphones or speakers and includes non-spatial background noise, such as air-handling equipment, and spatial sounds associated with specific equipment racks, such as compressors or fans. Changes can be made to equipment rack locations that produce changes in both the radiation shielding and system noise. The ISSES application allows for interactive investigation and collaborative trade studies between radiation shielding and noise for crew safety and comfort.

  3. Wireless Communication Enhancement Methods for Mobile Robots in Radiation Environments

    CERN Document Server

    Nattanmai Parasuraman, Ramviyas; Ferre, Manuel

    In hostile environments such as in scientific facilities where ionising radiation is a dominant hazard, reducing human interventions by increasing robotic operations are desirable. CERN, the European Organization for Nuclear Research, has around 50 km of underground scientific facilities, where wireless mobile robots could help in the operation of the accelerator complex, e.g. in conducting remote inspections and radiation surveys in different areas. The main challenges to be considered here are not only that the robots should be able to go over long distances and operate for relatively long periods, but also the underground tunnel environment, the possible presence of electromagnetic fields, radiation effects, and the fact that the robots shall in no way interrupt the operation of the accelerators. Having a reliable and robust wireless communication system is essential for successful execution of such robotic missions and to avoid situations of manual recovery of the robots in the event that the robot runs ...

  4. Travel for the 2004 American Statistical Association Biannual Radiation Meeting: "Radiation in Realistic Environments: Interactions Between Radiation and Other Factors

    Energy Technology Data Exchange (ETDEWEB)

    Brenner, David J.

    2009-07-21

    The 16th ASA Conference on Radiation and Health, held June 27-30, 2004 in Beaver Creek, CO, offered a unique forum for discussing research related to the effects of radiation exposures on human health in a multidisciplinary setting. The Conference furnishes investigators in health related disciplines the opportunity to learn about new quantitative approaches to their problems and furnishes statisticians the opportunity to learn about new applications for their discipline. The Conference was attended by about 60 scientists including statisticians, epidemiologists, biologists and physicists interested in radiation research. For the first time, ten recipients of Young Investigator Awards participated in the conference. The Conference began with a debate on the question: “Do radiation doses below 1 cGy increase cancer risks?” The keynote speaker was Dr. Martin Lavin, who gave a banquet presentation on the timely topic “How important is ATM?” The focus of the 2004 Conference on Radiation and Health was Radiation in Realistic Environments: Interactions Between Radiation and Other Risk Modifiers. The sessions of the conference included: Radiation, Smoking, and Lung Cancer Interactions of Radiation with Genetic Factors: ATM Radiation, Genetics, and Epigenetics Radiotherapeutic Interactions The Conference on Radiation and Health is held bi-annually, and participants are looking forward to the 17th conference to be held in 2006.

  5. Recent Developments in the Radiation Belt Environment Model

    Science.gov (United States)

    Fok, M.-C.; Glocer, A.; Zheng, Q.; Horne, R. B.; Meredith, N. P.; Albert, J. M.; Nagai, T.

    2010-01-01

    The fluxes of energetic particles in the radiation belts are found to be strongly controlled by the solar wind conditions. In order to understand and predict the radiation particle intensities, we have developed a physics-based Radiation Belt Environment (RBE) model that considers the influences from the solar wind, ring current and plasmasphere. Recently, an improved calculation of wave-particle interactions has been incorporated. In particular, the model now includes cross diffusion in energy and pitch-angle. We find that the exclusion of cross diffusion could cause significant overestimation of electron flux enhancement during storm recovery. The RBE model is also connected to MHD fields so that the response of the radiation belts to fast variations in the global magnetosphere can be studied.Weare able to reproduce the rapid flux increase during a substorm dipolarization on 4 September 2008. The timing is much shorter than the time scale of wave associated acceleration.

  6. Radiation Belt Environment Model: Application to Space Weather and Beyond

    Science.gov (United States)

    Fok, Mei-Ching H.

    2011-01-01

    Understanding the dynamics and variability of the radiation belts are of great scientific and space weather significance. A physics-based Radiation Belt Environment (RBE) model has been developed to simulate and predict the radiation particle intensities. The RBE model considers the influences from the solar wind, ring current and plasmasphere. It takes into account the particle drift in realistic, time-varying magnetic and electric field, and includes diffusive effects of wave-particle interactions with various wave modes in the magnetosphere. The RBE model has been used to perform event studies and real-time prediction of energetic electron fluxes. In this talk, we will describe the RBE model equation, inputs and capabilities. Recent advancement in space weather application and artificial radiation belt study will be discussed as well.

  7. Adaptation of radiation shielding code to space environment

    Energy Technology Data Exchange (ETDEWEB)

    Okuno, Koichi; Hara, Akihisa (Hazama Corp., Tokyo (Japan))

    1992-12-01

    Recently, the trend to the development of space has heightened. To the development of space, many problems are related, and as one of them, there is the protection from cosmic ray. The cosmic ray is the radiation having ultrahigh energy, and there was not the radiation shielding design code that copes with cosmic ray so far. Therefore, the high energy radiation shielding design code for accelerators was improved so as to cope with the peculiarity that cosmic ray possesses. Moreover, the calculation of the radiation dose equivalent rate in the moon base to which the countermeasures against cosmic ray were taken was simulated by using the improved code. As the important countermeasures for the safety protection from radiation, the covering with regolith is carried out, and the effect of regolith was confirmed by using the improved code. Galactic cosmic ray, solar flare particles, radiation belt, the adaptation of the radiation shielding code HERMES to space environment, the improvement of the three-dimensional hadron cascade code HETCKFA-2 and the electromagnetic cascade code EGS 4-KFA, and the cosmic ray simulation are reported. (K.I.).

  8. High-Performance, Radiation-Hardened Electronics for Space Environments

    Science.gov (United States)

    Keys, Andrew S.; Watson, Michael D.; Frazier, Donald O.; Adams, James H.; Johnson, Michael A.; Kolawa, Elizabeth A.

    2007-01-01

    The Radiation Hardened Electronics for Space Environments (RHESE) project endeavors to advance the current state-of-the-art in high-performance, radiation-hardened electronics and processors, ensuring successful performance of space systems required to operate within extreme radiation and temperature environments. Because RHESE is a project within the Exploration Technology Development Program (ETDP), RHESE's primary customers will be the human and robotic missions being developed by NASA's Exploration Systems Mission Directorate (ESMD) in partial fulfillment of the Vision for Space Exploration. Benefits are also anticipated for NASA's science missions to planetary and deep-space destinations. As a technology development effort, RHESE provides a broad-scoped, full spectrum of approaches to environmentally harden space electronics, including new materials, advanced design processes, reconfigurable hardware techniques, and software modeling of the radiation environment. The RHESE sub-project tasks are: SelfReconfigurable Electronics for Extreme Environments, Radiation Effects Predictive Modeling, Radiation Hardened Memory, Single Event Effects (SEE) Immune Reconfigurable Field Programmable Gate Array (FPGA) (SIRF), Radiation Hardening by Software, Radiation Hardened High Performance Processors (HPP), Reconfigurable Computing, Low Temperature Tolerant MEMS by Design, and Silicon-Germanium (SiGe) Integrated Electronics for Extreme Environments. These nine sub-project tasks are managed by technical leads as located across five different NASA field centers, including Ames Research Center, Goddard Space Flight Center, the Jet Propulsion Laboratory, Langley Research Center, and Marshall Space Flight Center. The overall RHESE integrated project management responsibility resides with NASA's Marshall Space Flight Center (MSFC). Initial technology development emphasis within RHESE focuses on the hardening of Field Programmable Gate Arrays (FPGA)s and Field Programmable Analog

  9. Basic mechanisms of radiation effects in the natural space radiation environment

    Energy Technology Data Exchange (ETDEWEB)

    Schwank, J.R.

    1994-06-01

    Four general topics are covered in respect to the natural space radiation environment: (1) particles trapped by the earth`s magnetic field, (2) cosmic rays, (3) radiation environment inside a spacecraft, (4) laboratory radiation sources. The interaction of radiation with materials is described by ionization effects and displacement effects. Total-dose effects on MOS devices is discussed with respect to: measurement techniques, electron-hole yield, hole transport, oxide traps, interface traps, border traps, device properties, case studies and special concerns for commercial devices. Other device types considered for total-dose effects are SOI devices and nitrided oxide devices. Lastly, single event phenomena are discussed with respect to charge collection mechanisms and hard errors. (GHH)

  10. The radiation environment in Sweden; Straalmiljoen i Sverige

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Paal; Carlsson, Monica; Falk, Rolf; Hubbard, Lynn; Leitz, Wolfram; Mjoenes, Lars; Moere, Hans; Nyblom, Leif; Soederman, Ann-Louise; Yuen Lasson, Katarina; Aakerblom, Gustav; Oehlen, Elisabeth

    2007-01-15

    The report describes, and reports data from, the monitoring of the radiation environment which has been conducted in Sweden since the 1950s. Average doses to the general public as well as to special groups of the public are also reported. Environmental monitoring concerning radiation has to a great extent focused on deposition and occurrence of radioactive elements originating from the atmospheric nuclear weapon tests and the Chernobyl accident. The average dose from {sup 137}Cs is very low, although it is somewhat higher in the group 'reindeer herders'. Surveys of naturally occurring radioactive elements in soil, drinking water and indoor air show that radiation from soil and building materials constitutes, besides medical use of radiation, the main part of the average total dose to the population. The dose from drinking water from drilled wells or from radon in indoor air may dominate the total dose in certain cases. Smoking increases the risk of radon considerably. UV-radiation has increased with 10 percent over the last 22 years at the location of the monitoring station. This is mainly explained by a decreased cloudiness. The exposure for UV is however more dependent on behaviour, and approximately 25 percent of the total exposure takes place abroad. Presently there are no time series concerning electromagnetic fields in the outdoor environment. However, measurements indicate levels well below the reference values.

  11. Radiation Belt Storm Probes—Observatory and Environments

    Science.gov (United States)

    Kirby, Karen; Artis, David; Bushman, Stewart; Butler, Michael; Conde, Rich; Cooper, Stan; Fretz, Kristen; Herrmann, Carl; Hill, Adrian; Kelley, Jeff; Maurer, Richard; Nichols, Richard; Ottman, Geffrey; Reid, Mark; Rogers, Gabe; Srinivasan, Dipak; Troll, John; Williams, Bruce

    2013-11-01

    The National Aeronautics and Space Administration's (NASA's) Radiation Belt Storm Probe (RBSP) is an Earth-orbiting mission that launched August 30, 2012, and is the latest science mission in NASA's Living with a Star Program. The RBSP mission will investigate, characterize and understand the physical dynamics of the radiation belts, as well as the influence of the Sun on the Earth's environment, by measuring particles, electric and magnetic fields and waves that comprise geospace. The mission is composed of two identically instrumented spinning observatories in an elliptical orbit around earth with 600 km perigee, 30,000 km apogee and 10∘ inclination to provide full sampling of the Van Allen radiation belts. The twin RBSP observatories (recently renamed the Van Allen Probes) will follow slightly different orbits and will lap each other four times per year, offering simultaneous measurements over a range of observatory separation distances. A description of the observatory environment is provided along with protection for sensitive electronics to support operations in the harsh radiation belt environment. Spacecraft and subsystem key characteristics and instrument accommodations are included that allow the RBSP science objectives to be met.

  12. A space radiation shielding model of the Martian radiation environment experiment (MARIE)

    Science.gov (United States)

    Atwell, W.; Saganti, P.; Cucinotta, F. A.; Zeitlin, C. J.

    2004-01-01

    The 2001 Mars Odyssey spacecraft was launched towards Mars on April 7, 2001. Onboard the spacecraft is the Martian radiation environment experiment (MARIE), which is designed to measure the background radiation environment due to galactic cosmic rays (GCR) and solar protons in the 20-500 MeV/n energy range. We present an approach for developing a space radiation-shielding model of the spacecraft that includes the MARIE instrument in the current mapping phase orientation. A discussion is presented describing the development and methodology used to construct the shielding model. For a given GCR model environment, using the current MARIE shielding model and the high-energy particle transport codes, dose rate values are compared with MARIE measurements during the early mapping phase in Mars orbit. The results show good agreement between the model calculations and the MARIE measurements as presented for the March 2002 dataset. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

  13. Radiation environment at LEO orbits: MC simulation and experimental data.

    Science.gov (United States)

    Zanini, Alba; Borla, Oscar; Damasso, Mario; Falzetta, Giuseppe

    The evaluations of the different components of the radiation environment in spacecraft, both in LEO orbits and in deep space is of great importance because the biological effect on humans and the risk for instrumentation strongly depends on the kind of radiation (high or low LET). That is important especially in view of long term manned or unmanned space missions, (mission to Mars, solar system exploration). The study of space radiation field is extremely complex and not completely solved till today. Given the complexity of the radiation field, an accurate dose evaluation should be considered an indispensable part of any space mission. Two simulation codes (MCNPX and GEANT4) have been used to assess the secondary radiation inside FO-TON M3 satellite and ISS. The energy spectra of primary radiation at LEO orbits have been modelled by using various tools (SPENVIS, OMERE, CREME96) considering separately Van Allen protons, the GCR protons and the GCR alpha particles. This data are used as input for the two MC codes and transported inside the spacecraft. The results of two calculation meth-ods have been compared. Moreover some experimental results previously obtained on FOTON M3 satellite by using TLD, Bubble dosimeter and LIULIN detector are considered to check the performances of the two codes. Finally the same experimental device are at present collecting data on the ISS (ASI experiment BIOKIS -nDOSE) and at the end of the mission the results will be compared with the calculation.

  14. Combined injury syndrome in space-related radiation environments

    Science.gov (United States)

    Dons, R. F.; Fohlmeister, U.

    The risk of combined injury (CI) to space travelers is a function of exposure to anomalously large surges of a broad spectrum of particulate and photon radiations, conventional trauma (T), and effects of weightlessness including decreased intravascular fluid volume, and myocardial deconditioning. CI may occur even at relatively low doses of radiation which can synergistically enhance morbidity and mortality from T. Without effective countermeasures, prolonged residence in space is expected to predispose most individuals to bone fractures as a result of calcium loss in the microgravity environment. Immune dysfunction may occur from residence in space independent of radiation exposure. Thus, wound healing would be compromised if infection were to occur. Survival of the space traveler with CI would be significantly compromised if there were delays in wound closure or in the application of simple supportive medical or surgical therapies. Particulate radiation has the potential for causing greater gastrointestinal injury than photon radiation, but bone healing should not be compromised at the expected doses of either type of radiation in space.

  15. RADIATION ENVIRONMENT, ORGANIZATION AND PROVIDING OF POPULATION RADIATION PROTECTION CONTROL IN ST. PETBURG

    Directory of Open Access Journals (Sweden)

    I. A. Rakitin

    2008-01-01

    Full Text Available The article presents the analysis of radiation environment and work experience of Rospotrebnadzor Administration in St. Petersburg in the field of organizing of population radiation protection control and interaction with the local government executive bodies. It shows the level and structure of the city population collective doses from the main dose forming ionizing irradiation sources. It emphasizes the integrated method of solving the population exposure limitation issues based on the results of radiation-hygienic passport system and on the data from Uniform State System for Doses Control and Registration. The evaluation of the work being carried out is given.

  16. Saturn Ring Radiation Environment for the Cassini Grand Finale Orbits

    Science.gov (United States)

    Cooper, John F.; Kollmann, Peter; Johnson, Robert E.; Roussos, Elias; Sittler, Edward C.; Sturner, Steven J.

    2016-10-01

    Grand Finale (proximal) orbits of Cassini from April to September 2017 will provide an unprecedented opportunity for further in-situ exploration of the energetic radiation environment primarily arising from galactic cosmic ray interactions with the main rings. Improved modeling of these interactions contributes to ring mass properties, radiation chemistry, and source modeling for trapped radiation within and beyond the rings. Our new GEANT simulations show that these interactions produce very substantial fluxes of secondary gamma rays, neutrons, electrons, protons, and more short-lived particles. Cosmic ray albedo neutron decay from ring neutron emissions provides the primary source of trapped protons near and above 10 MeV in the radiation belts extending from beyond the F ring to the orbit of Tethys. Fluxes of these high-energy trapped protons increased as expected with declining solar activity from 2004 through 2009, consistent with decreasing modulation of the galactic cosmic ray protons and heavier ions by the solar wind. In 2017 solar activity and modulation will again be declining from earlier maximum levels in 2012 - 2014, while solar illumination of the rings will be near solstice levels. There may then be similarities in the ring radiation and plasma environment to conditions in 2004. In comparison, the 1979 traversal of the main rings by Pioneer 11 occurred during peak solar activity but declining cosmic ray flux. The questions are then what radiation environment we might expect to find during the Grand Finale orbits, how would the Cassini MIMI LEMMS sensor respond to this environment, and how might these new measurements change our understanding of the rings? During SOI flyover of the rings, LEMMS nominal data showed intensities higher than those from Pioneer 11 to an extent that cannot be explained by the updated interaction model. LEMMS more likely responded to penetrating high-energy radiation at energies outside its nominal ranges for electrons and

  17. A virtual environment for medical radiation collaborative learning.

    Science.gov (United States)

    Bridge, Pete; Trapp, Jamie V; Kastanis, Lazaros; Pack, Darren; Parker, Jacqui C

    2015-06-01

    A software-based environment was developed to provide practical training in medical radiation principles and safety. The Virtual Radiation Laboratory application allowed students to conduct virtual experiments using simulated diagnostic and radiotherapy X-ray generators. The experiments were designed to teach students about the inverse square law, half value layer and radiation protection measures and utilised genuine clinical and experimental data. Evaluation of the application was conducted in order to ascertain the impact of the software on students' understanding, satisfaction and collaborative learning skills and also to determine potential further improvements to the software and guidelines for its continued use. Feedback was gathered via an anonymous online survey consisting of a mixture of Likert-style questions and short answer open questions. Student feedback was highly positive with 80 % of students reporting increased understanding of radiation protection principles. Furthermore 72 % enjoyed using the software and 87 % of students felt that the project facilitated collaboration within small groups. The main themes arising in the qualitative feedback comments related to efficiency and effectiveness of teaching, safety of environment, collaboration and realism. Staff and students both report gains in efficiency and effectiveness associated with the virtual experiments. In addition students particularly value the visualisation of "invisible" physical principles and increased opportunity for experimentation and collaborative problem-based learning. Similar ventures will benefit from adopting an approach that allows for individual experimentation while visualizing challenging concepts.

  18. The radiation environment in underground workplaces of the LHC

    CERN Document Server

    Theis, C; Kindl, Peter

    2007-01-01

    Active dose-monitoring of workplaces is crucial in order to operate a high-energy particle accelerator safely. As the mixed radiation fields that are expected in the environment of the Large Hadron Collider (LHC) are very different from standard use-cases like in nuclear power plants, it is of highest importance to characterize and calibrate radiation monitoring equipment appropriately for their use in high energy mixed radiation fields. Due to their sensitivity to different particle types over a larger energy range high-pressure ionization chambers have already been used at CERN and they are foreseen to be included within the radiation monitoring system of the LHC. In the framework of this thesis a new method was developed which allows for appropriate field-specific calibration of these detectors using Monte Carlo simulations. Therefore, the application of common 238Pu-Be source based calibration in mixed radiation fields was studied and compared to more accurate field specific calibration based on FLUKA Mon...

  19. Radiation effects on materials in high-radiation environments: A workshop summary

    Science.gov (United States)

    Weber, W. J.; Mansur, L. K.; Clinard, F. W.; Parkin, D. M.

    1991-08-01

    A workshop on Radiation Effects on Materials in High-Radiation Environments was held in Salt Lake City, Utah (USA) from August 13 to 15, 1990 under the auspices of the Division of Materials Sciences, Office of Basic Energy Sciences, US Department of Energy. The workshop focused on ceramics, alloys, and intermetallics and covered research needs and capabilities, recent experimental data, theory, and computer simulations. It was concluded that there is clearly a continuing scientific and technological need for fundamental knowledge on the underlying causes of radiation-induced property changes in materials. Furthermore, the success of many current and emerging nuclear-related technologies critically depend on renewed support for basic radiation-effects research, irradiation facilities, and training of scientists. The highlights of the workshop are reviewed and specific recommendations are made regarding research needs.

  20. The Martian Radiation Environment Experiment -- Results and Status

    Science.gov (United States)

    Zeitlin, C.; Cleghorn, T. F.; Cucinotta, F. A.; Saganti, P.; Andersen, V.; Lee, K. T.; Pinsky, L. S.; Atwell, W.; Turner, R.

    2004-05-01

    Ionizing radiation in space presents a potentially serious health hazard to astronauts on long-duration missions. Missions that take humans outside the geomagnetosphere (which provides significant shielding for crews in low-Earth orbit) are of particular concern. A mission to Mars would expose a crew to a substantial radiation dose from high-energy heavy ions in the Galactic Cosmic Radiation (GCR). Though not expected to cause acute effects, such exposures might endanger the long-term health of crewmembers, leading to increased risk of late effects such as cancer and cataract. Since the biological effects of these ions are not well understood, NASA cannot yet specify career limits for deep-space missions. While ground-based research in radiobiology continues, it is necessary to characterize the radiation field on the Martian surface. This is determined by the radiation incident on the top of the Martian atmosphere, the transmission properties of the atmosphere, and the production of secondary particles (neutrons in particular) in the upper part of the surface. The Martian Radiation Environment Experiment (MARIE), aboard the 2001 Mars Odyssey spacecraft, has returned the first detailed measurements of the radiation field incident on the atmosphere. MARIE consists of a stack of silicon charged-particle detectors, designed to measure the nearly-constant flux of energetic Galactic Cosmic Rays (GCR) and intermittent Solar Particle Events (SPE). The detector is optimized for the detection of solar protons and helium in the energy range from 30 to 75 MeV/nucleon, though higher energies and heavier ions are also detected. Despite considerable uncertainties in data normalization, the measured dose agrees with model calculations, to an accuracy well within the (conservatively) estimated errors. As of this writing (Feb. 2004), MARIE is off, having sustained damage during the large Solar Particle Event of Oct. 29, 2003. Attempts to recover the instrument will resume in the

  1. GEM detectors development for radiation environment: neutron tests and simulations

    Science.gov (United States)

    Chernyshova, Maryna; Jednoróg, Sławomir; Malinowski, Karol; Czarski, Tomasz; Ziółkowski, Adam; Bieńkowska, Barbara; Prokopowicz, Rafał; Łaszyńska, Ewa; Kowalska-Strzeciwilk, Ewa; Poźniak, Krzysztof T.; Kasprowicz, Grzegorz; Zabołotny, Wojciech; Wojeński, Andrzej; Krawczyk, Rafał D.; Linczuk, Paweł; Potrykus, Paweł; Bajdel, Barcel

    2016-09-01

    One of the requests from the ongoing ITER-Like Wall Project is to have diagnostics for Soft X-Ray (SXR) monitoring in tokamak. Such diagnostics should be focused on tungsten emission measurements, as an increased attention is currently paid to tungsten due to a fact that it became a main candidate for the plasma facing material in ITER and future fusion reactor. In addition, such diagnostics should be able to withstand harsh radiation environment at tokamak during its operation. The presented work is related to the development of such diagnostics based on Gas Electron Multiplier (GEM) technology. More specifically, an influence of neutron radiation on performance of the GEM detectors is studied both experimentally and through computer simulations. The neutron induced radioactivity (after neutron source exposure) was found to be not pronounced comparing to an impact of other secondary neutron reaction products (during the exposure).

  2. Internal Charging Design Environments for the Earths Radiation Belts

    Science.gov (United States)

    Minow, Joseph I.; Edwards, David L.

    2009-01-01

    Relativistic electrons in the Earth's radiation belts are a widely recognized threat to spacecraft because they penetrate lightly shielded vehicle hulls and deep into insulating materials where they accumulate to sufficient levels to produce electrostatic discharges. Strategies for evaluating the magnitude of the relativistic electron flux environment and its potential for producing ESD events are varied. Simple "rule of thumb" estimates such as the widely used 10(exp 10) e-/sq cm fluence within 10 hour threshold for the onset of pulsing in dielectric materials provide a quick estimate of when to expect charging issues. More sophisticated strategies based on models of the trapped electron flux within the Earth s magnetic field provide time dependent estimates of electron flux along spacecraft orbits and orbit integrate electron flux. Finally, measurements of electron flux can be used to demonstrate mean and extreme relativistic electron environments. This presentation will evaluate strategies used to specify energetic electron flux and fluence environments along spacecraft trajectories in the Earth s radiation belts.

  3. Buckling analysis of a cylindrical shell, under neutron radiation environment

    Energy Technology Data Exchange (ETDEWEB)

    Arani, A. Ghorbanpour [Department of Mechanical Engineering, School of Engineering, University of Kashan, Kashan (Iran, Islamic Republic of); Ahmadi, M. [School of Research and Development of Nuclear Reactors and Accelerators, Nuclear Science and Technology (Iran, Islamic Republic of); Ahmadi, A. [Department of Management, University of Tehran, Tehran (Iran, Islamic Republic of); Rastgoo, A. [Department of Mechanical Engineering, School of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Sepyani, H.A., E-mail: hosepiani@yahoo.com [Department of Mechanical Engineering, School of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer The work investigates the buckling of a shell in the neutron radiation environment. Black-Right-Pointing-Pointer Radiation induced porosity in elastic materials affects the material's properties. Black-Right-Pointing-Pointer The data based technique was used to determine the volume fraction porosity. Black-Right-Pointing-Pointer The theoretical formulations are presented based on the classical shell theory (CST). Black-Right-Pointing-Pointer It was concluded that both T and neutron induced swelling have significant effects. - Abstract: This research investigates the buckling of a cylindrical shell in the neutron radiation environment, subjected to combined static and periodic axial forces. Radiation induced porosity in elastic materials affects the thermal, electrical and mechanical properties of the materials. In this study, the data based technique was used to determine the volume fraction porosity, P, of shell material. A least-squares fit of the Young's module data yielded the estimated Young's modulus. The shell assumed made of iron irradiated in the range of 2-15e-7 dPa/s at 345-650 Degree-Sign C and theoretical formulations are presented based on the classical shell theory (CST). The research deals with the problem theoretically; keeping in mind that one means of generating relevant design data is to investigate prototype structures. A parametric study is followed and the stability of shell is discussed. It is concluded that both temperature and neutron induced swelling have significant effects on the buckling load.

  4. Radiation Hardened Electronics Destined For Severe Nuclear Reactor Environments

    Energy Technology Data Exchange (ETDEWEB)

    Holbert, Keith E. [Arizona State Univ., Tempe, AZ (United States); Clark, Lawrence T. [Arizona State Univ., Tempe, AZ (United States)

    2016-02-19

    Post nuclear accident conditions represent a harsh environment for electronics. The full station blackout experience at Fukushima shows the necessity for emergency sensing capabilities in a radiation-enhanced environment. This NEET (Nuclear Energy Enabling Technologies) research project developed radiation hardened by design (RHBD) electronics using commercially available technology that employs commercial off-the-shelf (COTS) devices and present generation circuit fabrication techniques to improve the total ionizing dose (TID) hardness of electronics. Such technology not only has applicability to severe accident conditions but also to facilities throughout the nuclear fuel cycle in which radiation tolerance is required. For example, with TID tolerance to megarads of dose, electronics could be deployed for long-term monitoring, inspection and decontamination missions. The present work has taken a two-pronged approach, specifically, development of both board and application-specific integrated circuit (ASIC) level RHBD techniques. The former path has focused on TID testing of representative microcontroller ICs with embedded flash (eFlash) memory, as well as standalone flash devices that utilize the same fabrication technologies. The standalone flash devices are less complicated, allowing better understanding of the TID response of the crucial circuits. Our TID experiments utilize biased components that are in-situ tested, and in full operation during irradiation. A potential pitfall in the qualification of memory circuits is the lack of rigorous testing of the possible memory states. For this reason, we employ test patterns that include all ones, all zeros, a checkerboard of zeros and ones, an inverse checkerboard, and random data. With experimental evidence of improved radiation response for unbiased versus biased conditions, a demonstration-level board using the COTS devices was constructed. Through a combination of redundancy and power gating, the demonstration

  5. Effect of ionizing radiation on the waste package environment

    Energy Technology Data Exchange (ETDEWEB)

    Reed, D.T. [Argonne National Lab., IL (USA); Van Konynenburg, R.A. [Lawrence Livermore National Lab., CA (USA)

    1991-05-01

    The radiolytic production of nitrogen oxides, nitrogen acids and ammonia are discussed in relation to the expected environment in a high-level waste repository that may be constructed at the Yucca Mountain site if it is found to be suitable. Both literature data and repository-relevant data are summarized for air-water vapor systems. The limiting cases of a dry air and a pure water vapor gas phase are also discussed. Design guidelines and recommendations, based solely on the potential consequence of radiation enhancement of corrosion, are given. 13 refs., 5 figs., 1 tab.

  6. Polymer materials and component evaluation in acidic-radiation environments

    Science.gov (United States)

    Celina, M.; Gillen, K. T.; Malone, G. M.; Clough, R. L.; Nelson, W. H.

    2001-07-01

    Polymeric materials used for cable/wire insulation, electrical connectors, O-rings, seals, and in critical components such as motors, level switches and resistive thermo-devices were evaluated under accelerated degradation conditions in combined radiation-oxidative elevated-temperature acidic-vapor (nitric/oxalic) environments relevant to conditions in isotope processing facilities. Experiments included the assessment of individual materials such as PEEK, polyimides, polyolefin based cable insulation, EPDM rubbers, various epoxy systems, commercial caulking materials as well as some functional testing of components. We discuss how to conduct laboratory experiments to simulate such complex hostile environments, describe some degradation effects encountered, and evaluate the impact on appropriate material and component selection.

  7. The ST environment: Expected charged particle radiation levels

    Science.gov (United States)

    Stassinopoulos, E. G.

    1978-01-01

    The external (surface incident) charged particle radiation, predicted for the ST satellite at the three different mission altitudes, was determined in two ways: (1) by orbital flux-integration and (2) by geographical instantaneous flux-mapping. The latest standard models of the environment were used in this effort. Magnetic field definitions for three nominal circular trajectories and for the geographic mapping positions were obtained from a current field model. Spatial and temporal variations or conditions affecting the static environment models were considered and accounted for, wherever possible. Limited shielding and dose evaluations were performed for a simple geometry. Results, given in tabular and graphical form, are analyzed, explained, and discussed. Conclusions are included.

  8. A New Vertical JFET Power Device for Harsh Radiation Environments

    Directory of Open Access Journals (Sweden)

    Pablo Fernández-Martínez

    2017-02-01

    Full Text Available An increasing demand for power electronic devices able to be operative in harsh radiation environments is now taking place. Specifically, in High Energy Physics experiments the required power devices are expected to withstand very high radiation levels which are normally too hard for most of the available commercial solutions. In this context, a new vertical junction field effect transistor (JFET has been designed and fabricated at the Instituto de Microelectrónica de Barcelona, Centro Nacional de Microelectrónica (IMB-CNM, CSIC. The new silicon V-JFET devices draw upon a deep-trenched technology to achieve volume conduction and low switch-off voltage, together with a moderately high voltage capability. The first batches of V-JFET prototypes have been already fabricated at the IMB-CNM clean room, and several aspects of their design, fabrication and the outcome of their characterization are summarized and discussed in this paper. Radiation hardness of the fabricated transistors have been tested both with gamma and neutron irradiations, and the results are also included in the contribution.

  9. Radiative shocks create environments for dust formation in novae

    CERN Document Server

    Derdzinski, Andrea M; Lazzati, Davide

    2016-01-01

    Classical novae commonly show evidence of rapid dust formation within months of the outburst. However, it is unclear how molecules and grains are able to condense within the ejecta given the potentially harsh environment created by ionizing radiation from the white dwarf. Motivated by the evidence for powerful radiative shocks within nova outflows, we propose that dust formation occurs within the cool, dense shell behind these shocks. We incorporate a simple molecular chemistry network and classical nucleation theory with a model for the thermodynamic evolution of the post-shock gas to demonstrate the formation of both carbon and forsterite ($\\rm Mg_2SiO_4$) grains. The high densities due to radiative shock compression ($n \\sim 10^{14}$ cm$^{-3}$) result in CO saturation and rapid dust nucleation. Grains grow efficiently to large sizes $\\gtrsim 0.1\\mu$m, in agreement with IR observations of dust-producing novae, and with total dust masses sufficient to explain massive extinction events such as V705 Cas. As in...

  10. Diamond based detectors for high temperature, high radiation environments

    Science.gov (United States)

    Metcalfe, A.; Fern, G. R.; Hobson, P. R.; Smith, D. R.; Lefeuvre, G.; Saenger, R.

    2017-01-01

    Single crystal CVD diamond has many desirable properties as a radiation detector; exceptional radiation hardness and physical hardness, chemical inertness, low Z (close to human tissue, good for dosimetry and transmission mode applications), wide bandgap (high temperature operation with low noise and solar blind), an intrinsic pathway to fast neutron detection through the 12C(n,α)9Be reaction. This combination of radiation hardness, temperature tolerance and ability to detect mixed radiation types with a single sensor makes diamond particularly attractive as a detector material for harsh environments such as nuclear power station monitoring (fission and fusion) and oil well logging. Effective exploitation of these properties requires the development of a metallisation scheme to give contacts that remain stable over extended periods at elevated temperatures (up to 250°C in this instance). Due to the cost of the primary detector material, computational modelling is essential to best utilise the available processing methods for optimising sensor response through geometry and conversion media configurations and to fully interpret experimental data. Monte Carlo simulations of our diamond based sensor have been developed, using MCNP6 and FLUKA2011, assessing the sensor performance in terms of spectral response and overall efficiency as a function of the detector and converter geometry. Sensors with varying metallisation schemes for high temperature operation have been fabricated at Brunel University London and by Micron Semiconductor Limited. These sensors have been tested under a varied set of conditions including irradiation with fast neutrons and alpha particles at high temperatures. The presented study indicates that viable metallisation schemes for high temperature contacts have been successfully developed and the modelling results, supported by preliminary experimental data from partners, indicate that the simulations provide a reasonable representation of

  11. Atmospheric, Ionospheric, and Energetic Radiation Environments of Saturn's Rings

    Science.gov (United States)

    Cooper, J. F.; Kollmann, P.; Sittler, E. C., Jr.; Johnson, R. E.; Sturner, S. J.

    2015-12-01

    Planetary magnetospheric and high-energy cosmic ray interactions with Saturn's rings were first explored in-situ during the Pioneer 11 flyby in 1979. The following Voyager flybys produced a wealth of new information on ring structure and mass, and on spatial structure of the radiation belts beyond the main rings. Next came the Cassini Orbiter flyover of the rings during Saturn Orbital Insertion in 2004 with the first in-situ measurements of the ring atmosphere and plasma ionosphere. Cassini has since fully explored the radiation belt and magnetospheric plasma region beyond the main rings, discovering how Enceladus acts as a source of water group neutrals and water ions for the ion plasma. But do the main rings also substantially contribute by UV photolysis to water group plasma (H+, O+, OH+, H2O+, H3O+, O2+) and neutrals inwards from Enceladus? More massive rings, than earlier inferred from Pioneer 11 and Voyager observations, would further contribute by bulk ring ice radiolysis from interactions of galactic cosmic ray particles. Products of these interactions include neutron-decay proton and electron injection into the radiation belts beyond the main rings. How does radiolysis from moon and ring sweeping of the radiation belt particles compare with direct gas and plasma sources from the main rings and Enceladus? Can the magnetospheric ion and electron populations reasonably be accounted for by the sum of the ring-neutron-decay and outer magnetospheric inputs? Pioneer 11 made the deepest radial penetration into the C-ring, next followed by Cassini SOI. What might Cassini's higher-inclination proximal orbits reveal about the atmospheric, ionospheric, and energetic radiation environments in the D-ring and the proximal gap region? Recent modeling predicts a lower-intensity innermost radiation belt extending from the gap to the inner D-ring. Other remaining questions include the lifetimes of narrow and diffuse dust rings with respect to plasma and energetic particle

  12. Radiative shocks create environments for dust formation in classical novae

    Science.gov (United States)

    Derdzinski, Andrea M.; Metzger, Brian D.; Lazzati, Davide

    2017-08-01

    Classical novae commonly show evidence of rapid dust formation within months of the outburst. However, it is unclear how molecules and grains are able to condense within the ejecta, given the potentially harsh environment created by ionizing radiation from the white dwarf. Motivated by the evidence for powerful radiative shocks within nova outflows, we propose that dust formation occurs within the cool, dense shell behind these shocks. We incorporate a simple molecular chemistry network and classical nucleation theory with a model for the thermodynamic evolution of the post-shock gas, in order to demonstrate the formation of both carbon and forsterite (Mg2SiO4) grains. The high densities due to radiative shock compression (n ∼ 1014 cm-3) result in CO saturation and rapid dust nucleation. Grains grow efficiently to large sizes ≳ 0.1 μm, in agreement with IR observations of dust-producing novae, and with total dust masses sufficient to explain massive extinction events such as V705 Cas. As in dense stellar winds, dust formation is CO-regulated, with carbon-rich flows producing carbon-rich grains and oxygen-rich flows primarily forming silicates. CO is destroyed by non-thermal particles accelerated at the shock, allowing additional grain formation at late times, but the efficiency of this process appears to be low. Given observations showing that individual novae produce both carbonaceous and silicate grains, we concur with previous works attributing this bimodality to chemical heterogeneity of the ejecta. Nova outflows are diverse and inhomogeneous, and the observed variety of dust formation events can be reconciled by different abundances, the range of shock properties, and the observer viewing angle. The latter may govern the magnitude of extinction, with the deepest extinction events occurring for observers within the binary equatorial plane.

  13. BNCT-RTPE: BNCT radiation treatment planning environment

    Energy Technology Data Exchange (ETDEWEB)

    Wessol, D.E.; Wheeler, F.J. [Idaho National Engineering Lab., Idaho Fall, ID (United States); Babcock, R.S. [and others

    1995-11-01

    Several improvements have been developed for the BNCT radiation treatment planning environment (BNCT-Rtpe) during 1994. These improvements have been incorporated into Version 1.0 of BNCT-Rtpe which is currently installed at the INEL, BNL, Japanese Research Center (JRC), and Finland`s Technical Research Center. Platforms supported by this software include Hewlett-Packard (HP), SUN, International Business Machines (IBM), and Silicon Graphics Incorporated (SGI). A draft version of the BNCT-Rtpe user manual is available. Version 1.1 of BNCT-Rtpe is scheduled for release in March 1995. It is anticipated that Version 2.x of BNCT-Rtpe, which includes the nonproprietary NURBS library and data structures, will be released in September 1995.

  14. The radiation environment near the lunar surface: CRaTER observations and Geant4 simulations

    National Research Council Canada - National Science Library

    M D Looper; J E Mazur; J B Blake; H E Spence; N A Schwadron; M J Golightly; A W Case; J C Kasper; L W Townsend

    2013-01-01

      At the start of the Lunar Reconnaissance Orbiter mission in 2009, its Cosmic Ray Telescope for the Effects of Radiation instrument measured the radiation environment near the Moon during the recent...

  15. Modeling of the Martian Environment for Radiation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    De Angelis, G. [Istituto Superiore di Sanit, Rome, I-00161 (Italy); Badavi, F.F. [Christopher Newport University, Newport News, VA 23606 (United States); Blattnig, S.R.; Clowdsley, M.S. [NASA Langley Research Center, Hampton, VA 23681 (United States); Nealy, J.E. [Old Dominion University, Norfolk, VA 23508 (United States); Qualls, G.D.; Singleterry, R.C.; Tripathi, R.K.; Wilson, J.W. [NASA Langley Research Center, Hampton, VA 23681 (United States)

    2007-04-15

    Results for the radiation environment to be found on the planet Mars due to Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE) has been obtained. Primary particle environments computed for Martian conditions are transported within the Mars atmosphere, modeled in a time-dependent way in terms of density, pressure, and temperature vs. altitude, down to the surface, with topography and backscattering patterns taken into account. The atmospheric chemical and isotopic composition has been modeled over results from the in-situ Viking Lander measurements for both major and minor components. The surface topography has been determined by using a model based on the data provided by the Mars Orbiter Laser Altimeter (MOLA) instrument on board the Mars Global Surveyor (MGS) spacecraft. The surface itself has been modeled in both the dry ('regolith') and volatile components. Mars regolith composition has been modeled based on the measurements obtained with orbiter and lander spacecraft from which an average composition has been derived. The volatile inventory properties, both in the regolith and in the seasonal and perennial polar caps, has been taken into account by modeling the deposition of volatiles and its variations with geography and time all throughout the Martian year, from results from imaging data of orbiter spacecraft. Results are given in terms of fluxes, doses and LET, for most kinds of particles, namely protons, neutrons, alpha particles, heavy ions, pions, and muons for various soil compositions.

  16. Three keys to the radiation of angiosperms into freezing environments.

    Science.gov (United States)

    Zanne, Amy E; Tank, David C; Cornwell, William K; Eastman, Jonathan M; Smith, Stephen A; FitzJohn, Richard G; McGlinn, Daniel J; O'Meara, Brian C; Moles, Angela T; Reich, Peter B; Royer, Dana L; Soltis, Douglas E; Stevens, Peter F; Westoby, Mark; Wright, Ian J; Aarssen, Lonnie; Bertin, Robert I; Calaminus, Andre; Govaerts, Rafaël; Hemmings, Frank; Leishman, Michelle R; Oleksyn, Jacek; Soltis, Pamela S; Swenson, Nathan G; Warman, Laura; Beaulieu, Jeremy M

    2014-02-06

    Early flowering plants are thought to have been woody species restricted to warm habitats. This lineage has since radiated into almost every climate, with manifold growth forms. As angiosperms spread and climate changed, they evolved mechanisms to cope with episodic freezing. To explore the evolution of traits underpinning the ability to persist in freezing conditions, we assembled a large species-level database of growth habit (woody or herbaceous; 49,064 species), as well as leaf phenology (evergreen or deciduous), diameter of hydraulic conduits (that is, xylem vessels and tracheids) and climate occupancies (exposure to freezing). To model the evolution of species' traits and climate occupancies, we combined these data with an unparalleled dated molecular phylogeny (32,223 species) for land plants. Here we show that woody clades successfully moved into freezing-prone environments by either possessing transport networks of small safe conduits and/or shutting down hydraulic function by dropping leaves during freezing. Herbaceous species largely avoided freezing periods by senescing cheaply constructed aboveground tissue. Growth habit has long been considered labile, but we find that growth habit was less labile than climate occupancy. Additionally, freezing environments were largely filled by lineages that had already become herbs or, when remaining woody, already had small conduits (that is, the trait evolved before the climate occupancy). By contrast, most deciduous woody lineages had an evolutionary shift to seasonally shedding their leaves only after exposure to freezing (that is, the climate occupancy evolved before the trait). For angiosperms to inhabit novel cold environments they had to gain new structural and functional trait solutions; our results suggest that many of these solutions were probably acquired before their foray into the cold.

  17. Local Heliospheric and Interstellar Radiation Environment of Planet X

    Science.gov (United States)

    Cooper, John

    2017-01-01

    The orbit and aphelion direction of the putative Planet X at mass 10 ME has been inferred earlier from orbital modeling of Sedna and other distant Kuiper Belt Objects. The centroid of possible aphelion locations at 103 AU lies within the heliotail potentially extending thousands of AU downstream from the direction of interstellar neutral flow into the heliosphere. The only spacecraft now heading in that general direction is Pioneer 10, long silent since last contact in January 2003 at 82 AU from the Sun. The Interstellar Background Explorer (IBEX) has from Earth orbit, however, been mapping energetic neutral atom (ENA) emissions from the outer heliosphere, including in the heliotail direction. Angular resolutions of the IBEX ENA maps are too coarse to resolve Planet X itself but could inform on larger-scale particle flux environments of distant objects within the heliotail. Present Voyager 1 energetic particle measurements in the outer heliosheath will eventually be joined by Voyager 2 bulk plasma measurements at ion energies below 10 keV for more complete characterization of particle flux distributions. These distributions can then be used to model external radiation interactions with the more distant objects of our solar system, potentially including Planet X.

  18. Synchrotron radiation lithography system in an atmospheric environment (invited)

    Science.gov (United States)

    Okada, K.; Kouno, E.; Nomura, E.; Suzuki, K.; Fujii, K.; Tanaka, Y.; Iwata, J.; Kawase, Y.

    1989-07-01

    The atmospheric environmental exposure system for synchrotron radiation (SR) lithography has been integrated using the Photon Factory storage ring (2.5 GeV). The system, composed of a highly reliable beamline, an SR extracting chamber and a prototype SR stepper, aims at attaining higher accuracy and throughput. Based on a fail-safe mechanism notion, a double-vacuum protection system, in which two sets of a fast closing valve and acoustic delay line are installed in the main beamline and branch beamline, respectively, has been organized. Vacuum breakdown tests indicated that any vacuum breakdown, a beryllium (Be) window rupture in the worst case, exerts little influence on the storage ring ultrahigh vacuum. The SR extracting chamber, equipped with a Be window and an extraction window, is filled with helium at atmospheric pressure. Particularly, the 50-μm-thick, 35-mm-diam Be window, vacuum-sealed by a Viton O-ring, was preliminarily employed and, so far, has operated successfully, giving a 25-mm square exposure area. In terms of practical availability and simplicity, the SR stepper in an atmospheric environment has been constructed. A novel differential mode linear Fresnel zone plate alignment method, which can detect an alignment error between a mask and a wafer during exposure, was developed.

  19. Effects of Polarization-Maintaining Fibre Degrading on Precision of Fibre Optic Gyroscopes in Radiation Environment

    Institute of Scientific and Technical Information of China (English)

    XIAO Wen; LIU De-Wen; LIU Yang; YI Xiao-Su; CONG Lin

    2008-01-01

    @@ In the space environment, the precision of fibre optic gyroscopes (FOGs) degrades because of space radiation.Photonic components of FOGs axe affected by radiation, especially the polaxization-maintaining (PM) fibre coil.In relation to the space radiation environment characteristic, we have carried out a series of radiation experiments on a PM fibre coil with 60Co radiation source at different dose rates. Based on the experimental results, the formula between the PM-fibre loss and radiation dose rata is built, and the relation between the precision of FOG and radiation dose is obtained accordingly. The results strongly show that the precision of our FOG degrades owing to the attenuation of the polarization-maintaining fibre, which provides theoretical foundation for the radiation-resistant design of the FOG.

  20. Simulation and analysis of antennas radiating in a complex environment

    Science.gov (United States)

    Kim, J. J.; Burnside, W. D.

    1986-01-01

    A numerical procedure for computing the high-frequency radiation patterns of antennas mounted on curved surfaces is described. The procedure utilizes the uniform geometrical theory of diffraction to examine the antenna system's performance, which is dependent on antenna radiation patterns. Composite ellipsoid models of fuselage shapes are developed and the formation of geodesic paths on the models is studied; the shape of the fuselage affects the radiation patterns. The actual field radiated by the source and scattered by the structure is calculated using the ray field technique. The numerical solution is applied to the analysis of the antenna radiation patterns of a military aircraft, private aircraft, and the Space Shuttle orbiter. Good correlation between the calculated and measured radiation patterns is noted verifying the usefulness and accuracy of the numerical procedure.

  1. Activation and radiation damage in the environment of hadron accelerators

    CERN Document Server

    Kiselev, Daniela

    2013-01-01

    A component which suffers radiation damage usually also becomes radioactive, since the source of activation and radiation damage is the interaction of the material with particles from an accelerator or with reaction products. However, the underlying mechanisms of the two phenomena are different. These mechanisms are described here. Activation and radiation damage can have far-reaching consequences. Components such as targets, collimators, and beam dumps are the first candidates for failure as a result of radiation damage. This means that they have to be replaced or repaired. This takes time, during which personnel accumulate dose. If the dose to personnel at work would exceed permitted limits, remote handling becomes necessary. The remaining material has to be disposed of as radioactive waste, for which an elaborate procedure acceptable to the authorities is required. One of the requirements of the authorities is a complete nuclide inventory. The methods used for calculation of such inventories are presented,...

  2. Evaluation of the effects of solar radiation on glass. [space environment simulation

    Science.gov (United States)

    Firestone, R. F.; Harada, Y.

    1979-01-01

    The degradation of glass used on space structures due to electromagnetic and particulate radiation in a space environment was evaluated. The space environment was defined and a simulated space exposure apparatus was constructed. Four optical materials were exposed to simulated solar and particulate radiation in a space environment. Sapphire and fused silica experienced little change in transmittance, while optical crown glass and ultra low expansion glass darkened appreciably. Specimen selection and preparation, exposure conditions, and the effect of simulated exposure are discussed. A selective bibliography of the effect of radiation on glass is included.

  3. Qualification of the radiation environment in the TCC2 experimental test area.

    CERN Document Server

    Fynbo, C A

    2000-01-01

    This report qualifies the radiation environment to be found in the area behind the beam dump in the TCC2 experimental hall where tests are being performed on the radiation hardness and sensitivity to Single Event Upsets of electronics to be installed near the LHC machine. A comparison is made with the radiation environment expected for the LHC, and we conclude that the environment found in the test area matches that of LHC such that tests performed here will provide a valid simulation of electronics performance under LHC running conditions.

  4. Cryogenic Si detectors for ultra radiation hardness in SLHC environment

    Science.gov (United States)

    Li, Zheng; Abreu, M.; Anbinderis, P.; Anbinderis, T.; Ambrosio, N. D.'.; de Boer, W.; Borchi, E.; Borer, K.; Bruzzi, M.; Buontempo, S.; Chen, W.; Cindro, V.; Dierlamm, A.; Eremin, V.; Gaubas, E.; Gorbatenko, V.; Grigoriev, E.; Hauler, F.; Heijne, E.; Heising, S.; Hempel, O.; Herzog, R.; Härkönen, J.; Ilyashenko, I.; Janos, S.; Jungermann, L.; Kalesinskas, V.; Kapturauskas, J.; Laiho, R.; Luukka, P.; Mandic, I.; De Masi, Rita; Menichelli, D.; Mikuz, M.; Militaru, O.; Niinikosky, T. O.; Shea, V. O.'.; Pagano, S.; Paul, S.; Piotrzkowski, K.; Pretzl, K.; Rato Mendes, P.; Rouby, X.; Ruggiero, G.; Smith, K.; Sonderegger, P.; Sousa, P.; Tuominen, E.; Tuovinen, E.; Verbitskaya, E.; Vaitkus, J.; Wobst, E.; Zavrtanik, M.

    2007-09-01

    Radiation hardness up to 10 16 neq/cm 2 is required in the future HEP experiments for most inner detectors. However, 10 16 neq/cm 2 fluence is well beyond the radiation tolerance of even the most advanced semiconductor detectors fabricated by commonly adopted technologies: the carrier trapping will limit the charge collection depth to an effective range of 20-30 μm regardless of depletion depth. Significant improvement of the radiation hardness of silicon sensors has been taken place within RD39. Fortunately the cryogenic tool we have been using provides us a convenient way to solve the detector charge collection efficiency (CCE) problem at SLHC radiation level (10 16 neq/cm 2). There are two key approaches in our efforts: (1) use of the charge/current injection to manipulate the detector internal electric field in such a way that it can be depleted at a modest bias voltage at cryogenic temperature range (⩽230 K); and (2) freezing out of the trapping centers that affects the CCE at cryogenic temperatures lower than that of the LN 2 temperature. In our first approach, we have developed the advanced radiation hard detectors using charge or current injection, the current injected diodes (CID). In a CID, the electric field is controlled by injected current, which is limited by the space charge, yielding a nearly uniform electric field in the detector, independent of the radiation fluence. In our second approach, we have developed models of radiation-induced trapping levels and the physics of their freezing out at cryogenic temperatures. In this approach, we intend to study the trapping effect at temperatures below LN 2 temperature. A freeze-out of trapping can certainly help in the development of ultra-radiation hard Si detectors for SLHC. A detector CCE measurement system using ultra-fast picosecond laser with a He cryostat has been built at CERN. This system can be used to find out the practical cryogenic temperature range that can be used to freeze out the

  5. Cryogenic Si detectors for ultra radiation hardness in SLHC environment

    Energy Technology Data Exchange (ETDEWEB)

    Li Zheng [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Abreu, M. [LIP, Av. E. Garcia, P-1000 Lisbon (Portugal); Anbinderis, P.; Anbinderis, T. [University of Vilnius, Institute of Materials Science and Applied Research, 2040 Vilnius (Lithuania); Ambrosio, N.D' . [Instiuto di Cibernetica ' E. Caianiello' , 80078 Pozzuoli (Italy); Boer, W. de [IEKP University of Karlsruhe, D-76128 Karlsruhe (Germany); Borchi, E. [Dipartimento di Energetica, Universita di Firenze, I-50139 Florence (Italy); Borer, K. [Laboratorium fuer Hochenergiephysik der Universitaet Bern, Sidlerstarsse 5, CH-3012 Bern (Switzerland); Bruzzi, M. [Dipartimento di Energetica, Universita di Firenze, I-50139 Firenze (Italy); Buontempo, S. [Instiuto di Cibernetica ' E. Caianiello' , 80078 Pozzuoli (Italy); Chen, W. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Cindro, V. [Jozef Stefan Institute, Exp. Particle Physics Department, PO. Box 3000, 1001 Ljubljana (Slovenia); Dierlamm, A. [IEKP University of Karlsruhe, D-76128 Karlsruhe (Germany); Eremin, V. [Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation); Gaubas, E.; Gorbatenko, V. [University of Vilnius, Institute of Materials Science and Applied Research, 2040 Vilnius (Lithuania); Grigoriev, E. [IEKP University of Karlsruhe, D-76128 Karlsruhe (Germany); Department de Radiologie, Universite de Geneve, CH-1211 Geneva (Switzerland); Hauler, F. [IEKP University of Karlsruhe, D-76128 Karlsruhe (Germany); Heijne, E. [CERN, CH-1211 Geneva (Switzerland); Heising, S. [IEKP University of Karlsruhe, D-76128 Karlsruhe (Germany)] (and others)

    2007-09-01

    Radiation hardness up to 10{sup 16} n{sub eq}/cm{sup 2} is required in the future HEP experiments for most inner detectors. However, 10{sup 16} n{sub eq}/cm{sup 2} fluence is well beyond the radiation tolerance of even the most advanced semiconductor detectors fabricated by commonly adopted technologies: the carrier trapping will limit the charge collection depth to an effective range of 20-30 {mu}m regardless of depletion depth. Significant improvement of the radiation hardness of silicon sensors has been taken place within RD39. Fortunately the cryogenic tool we have been using provides us a convenient way to solve the detector charge collection efficiency (CCE) problem at SLHC radiation level (10{sup 16} n{sub eq}/cm{sup 2}). There are two key approaches in our efforts: (1) use of the charge/current injection to manipulate the detector internal electric field in such a way that it can be depleted at a modest bias voltage at cryogenic temperature range ({<=}230 K); and (2) freezing out of the trapping centers that affects the CCE at cryogenic temperatures lower than that of the LN{sub 2} temperature. In our first approach, we have developed the advanced radiation hard detectors using charge or current injection, the current injected diodes (CID). In a CID, the electric field is controlled by injected current, which is limited by the space charge, yielding a nearly uniform electric field in the detector, independent of the radiation fluence. In our second approach, we have developed models of radiation-induced trapping levels and the physics of their freezing out at cryogenic temperatures. In this approach, we intend to study the trapping effect at temperatures below LN{sub 2} temperature. A freeze-out of trapping can certainly help in the development of ultra-radiation hard Si detectors for SLHC. A detector CCE measurement system using ultra-fast picosecond laser with a He cryostat has been built at CERN. This system can be used to find out the practical

  6. Simulating protostellar evolution and radiative feedback in the cluster environment

    CERN Document Server

    Klassen, Mikhail; Peters, Thomas

    2011-01-01

    Radiative feedback is among the most important consequences of clustered star formation inside molecular clouds. At the onset of star formation, radiation from massive stars heats the surrounding gas, which suppresses the formation of many low-mass stars. When simulating pre-main-sequence stars, their stellar properties must be defined by a prestellar model. Different approaches to prestellar modeling may yield quantitatively different results. In this paper, we compare two existing prestellar models under identical initial conditions to gauge whether the choice of model has any significant effects on the final population of stars. The first model treats stellar radii and luminosities with a ZAMS model, while separately estimating the accretion luminosity by interpolating to published prestellar tracks. The second, more accurate prestellar model self-consistently evolves the radius and luminosity of each star under highly variable accretion conditions. Each is coupled to a raytracing-based radiative feedback ...

  7. LHCb: Evaluation of the Radiation Environment of the LHCb Experiment

    CERN Multimedia

    Karacson, M

    2011-01-01

    The characterization of all aspects of the radiation field of the LHCb experiment is needed to understand the impact of the unprecedented radiation levels to which its detector and electronics are exposed to. The methodology on how this is done is described. Analysis of the measurements of active and passive sensors of various types which are distributed in and around the detector will be carried out. Appropriate cross calibrations will be applied and comparisons between them will be performed. Critical comparisons with simulation results obtained with the FLUKA Monte Carlo code are also an essential element of the study.

  8. Exploration Technology Developments Program's Radiation Hardened Electronics for Space Environments (RHESE) Project Overview

    Science.gov (United States)

    Keys, Andrew S.; Adams, James H.; Darty, Ronald C.; Patrick, Marshall C.; Johnson, Michael A.; Cressler, John D.

    2008-01-01

    Primary Objective: 1) A computational tool to accurately predict electronics performance in the presence of space radiation in support of spacecraft design: a) Total dose; b) Single Event Effects; and c) Mean Time Between Failure. (Developed as successor to CR ME96.) Secondary Objectives: 2) To provide a detailed description of the natural radiation environment in support of radiation health and instrument design: a) In deep space; b) Inside the magnetosphere; and c) Behind shielding.

  9. Spacecraft Environments Interactive: Space Radiation and Its Effects on Electronic System

    Science.gov (United States)

    Howard, J. W., Jr.; Hardage, D. M.

    1999-01-01

    The natural space environment is characterized by complex and subtle phenomena hostile to spacecraft. Effects of these phenomena impact spacecraft design, development, and operation. Space systems become increasingly susceptible to the space environment as use of composite materials and smaller, faster electronics increases. This trend makes an understanding of space radiation and its effects on electronic systems essential to accomplish overall mission objectives, especially in the current climate of smaller/better/cheaper faster. This primer outlines the radiation environments encountered in space, discusses regions and types of radiation, applies the information to effects that these environments have on electronic systems, addresses design guidelines and system reliability, and stresses the importance of early involvement of radiation specialists in mission planning, system design, and design review (part-by-part verification).

  10. Mars' surface radiation environment measured with the Mars science laboratory's curiosity rover

    NARCIS (Netherlands)

    Hassler, D.M.; Zeitlin, C.; Wimmer-Schweingruber, R.F.; Ehresmann, B.; Rafkin, S.; Eigenbrode, J.L.; Brinza, D.E.; Weigle, G.; Böttcher, S.; Böhm, E.; Burmeister, S.; Guo, J.; Köhler, J.; Martin, C.; Reitz, G.; Cucinotta, F.A.; Kim, M.-H.; Grinspoon, D.; Bullock, M.A.; Posner, A.; Gómez-Elvira, J.; Vasavada, A.; Grotzinger, J.P.; MSL Science Team, the

    2014-01-01

    The Radiation Assessment Detector (RAD) on the Mars Science Laboratory’s Curiosity rover began making detailed measurements of the cosmic ray and energetic particle radiation environment on the surface of Mars on 7 August 2012. We report and discuss measurements of the absorbed dose and dose equival

  11. Mars' surface radiation environment measured with the Mars science laboratory's curiosity rover

    NARCIS (Netherlands)

    Hassler, D.M.; Zeitlin, C.; Wimmer-Schweingruber, R.F.; Ehresmann, B.; Rafkin, S.; Eigenbrode, J.L.; Brinza, D.E.; Weigle, G.; Böttcher, S.; Böhm, E.; Burmeister, S.; Guo, J.; Köhler, J.; Martin, C.; Reitz, G.; Cucinotta, F.A.; Kim, M.-H.; Grinspoon, D.; Bullock, M.A.; Posner, A.; Gómez-Elvira, J.; Vasavada, A.; Grotzinger, J.P.; MSL Science Team, the

    2014-01-01

    The Radiation Assessment Detector (RAD) on the Mars Science Laboratory’s Curiosity rover began making detailed measurements of the cosmic ray and energetic particle radiation environment on the surface of Mars on 7 August 2012. We report and discuss measurements of the absorbed dose and dose equival

  12. Sample Environment in Experiments using X-Ray Synchrotron Radiation

    DEFF Research Database (Denmark)

    Buras, B

    1984-01-01

    Modern electron (positron) storage rings are able to emit very intense X-ray radiation with a continuous spectrum extending to 0.1 A, from bending magnets and insertion devices (wavelength shifters and multipole wigglers). It can be used directly for white beam experiments and/or for monochromati...

  13. Diamond and silicon pixel detectors in high radiation environments

    Energy Technology Data Exchange (ETDEWEB)

    Tsung, Jieh-Wen

    2012-10-15

    Diamond pixel detector is a promising candidate for tracking of collider experiments because of the good radiation tolerance of diamond. The diamond pixel detector must withstand the radiation damage from 10{sup 16} particles per cm{sup 2}, which is the expected total fluence in High Luminosity Large Hadron Collider. The performance of diamond and silicon pixel detectors are evaluated in this research in terms of the signal-to-noise ratio (SNR). Single-crystal diamond pixel detectors with the most recent readout chip ATLAS FE-I4 are produced and characterized. Based on the results of the measurement, the SNR of diamond pixel detector is evaluated as a function of radiation fluence, and compared to that of planar-silicon ones. The deterioration of signal due to radiation damage is formulated using the mean free path of charge carriers in the sensor. The noise from the pixel readout circuit is simulated and calculated with leakage current and input capacitance to the amplifier as important parameters. The measured SNR shows good agreement with the calculated and simulated results, proving that the performance of diamond pixel detectors can exceed the silicon ones if the particle fluence is more than 10{sup 15} particles per cm{sup 2}.

  14. Performances of Kevlar and Polyethylene as radiation shielding on-board the International Space Station in high latitude radiation environment.

    Science.gov (United States)

    Narici, Livio; Casolino, Marco; Di Fino, Luca; Larosa, Marianna; Picozza, Piergiorgio; Rizzo, Alessandro; Zaconte, Veronica

    2017-05-10

    Passive radiation shielding is a mandatory element in the design of an integrated solution to mitigate the effects of radiation during long deep space voyages for human exploration. Understanding and exploiting the characteristics of materials suitable for radiation shielding in space flights is, therefore, of primary importance. We present here the results of the first space-test on Kevlar and Polyethylene radiation shielding capabilities including direct measurements of the background baseline (no shield). Measurements are performed on-board of the International Space Station (Columbus modulus) during the ALTEA-shield ESA sponsored program. For the first time the shielding capability of such materials has been tested in a radiation environment similar to the deep-space one, thanks to the feature of the ALTEA system, which allows to select only high latitude orbital tracts of the International Space Station. Polyethylene is widely used for radiation shielding in space and therefore it is an excellent benchmark material to be used in comparative investigations. In this work we show that Kevlar has radiation shielding performances comparable to the Polyethylene ones, reaching a dose rate reduction of 32 ± 2% and a dose equivalent rate reduction of 55 ± 4% (for a shield of 10 g/cm(2)).

  15. VCHP Radiators for Lunar and Martian Environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Long-term Lunar and Martian systems present challenges to thermal control systems, including changes in thermal load, and large changes in the thermal environment...

  16. VCHP Radiators for Lunar and Martian Environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Long-term Lunar and Martian systems present challenges to thermal systems, including changes in thermal load, and large changes in the thermal environment between...

  17. Atmospheric radiation environment analyses based-on CCD camera at various mountain altitudes and underground sites

    Directory of Open Access Journals (Sweden)

    Li Cavoli Pierre

    2016-01-01

    Full Text Available The purpose of this paper is to discriminate secondary atmospheric particles and identify muons by measuring the natural radiative environment in atmospheric and underground locations. A CCD camera has been used as a cosmic ray sensor. The Low Noise Underground Laboratory of Rustrel (LSBB, France gives the access to a unique low-noise scientific environment deep enough to ensure the screening from the neutron and proton radiative components. Analyses of the charge levels in pixels of the CCD camera induced by radiation events and cartographies of the charge events versus the hit pixel are proposed.

  18. MARS15 Simulation of Radiation Environment at the ESS Linac

    Energy Technology Data Exchange (ETDEWEB)

    Mokhov, N. V. [Fermilab; Eidelman, Yu. I. [Euclid Techlabs, Solon; Rakhno, I. L. [Fermilab; Tchelidze, L. [ESS, Lund; Tropin, I. S. [Fermilab

    2016-12-01

    Comprehensive studies with the MARS15(2016) Monte-Carlo code are described on evaluation of prompt and residual radiation levels induced by nominal and accidental beam losses in the 5-MW, 2-GeV European Spallation Source (ESS) Linac. These are to provide a basis for radiation shielding design verification through the accelerator complex. The calculation model is based on the latest engineering design and includes a sophisticated algorithm for particle tracking in the machine RF cavities as well as a well-established model of the beam loss. Substantial efforts were put in solving the deep-penetration problem for the thick shielding around the tunnel with numerous complex penetrations. It allowed us to study in detail not only the prompt dose, but also component and air activation, radiation loads on the soil outside the tunnel, and skyshine studies for the complicated 3-D surface above the machine. Among the other things, the newest features in MARS15 (2016), such as a ROOT-based beamline builder and a TENDL-based event generator for nuclear interactions below 100 MeV, were very useful in this challenging application

  19. Monte Carlo simulations of the radiation environment for the CMS Experiment

    CERN Document Server

    Mallows, Sophie

    2015-01-01

    Monte Carlo radiation transport codes are used by the CMS Beam Radiation Instrumentation and Luminosity (BRIL) project to estimate the radiation levels due to proton-proton collisions and machine induced background. Results are used by the CMS collaboration for various applications: comparison with detector hit rates, pile-up studies, predictions of radiation damage based on various models (Dose, NIEL, DPA), shielding design, estimations of residual dose environment. Simulation parameters, and the maintenance of the input files are summarised, and key results are presented. Furthermore, an overview of additional programs developed by the BRIL project to meet the specific needs of CMS community is given.

  20. Monte Carlo simulations of the radiation environment for the CMS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mallows, S., E-mail: sophie.mallows@cern.ch [KIT, Karlsruhe (Germany); Azhgirey, I.; Bayshev, I. [IHEP, Protvino (Russian Federation); Bergstrom, I.; Cooijmans, T.; Dabrowski, A.; Glöggler, L.; Guthoff, M. [CERN, Geneva (Switzerland); Kurochkin, I. [IHEP, Protvino (Russian Federation); Vincke, H.; Tajeda, S. [CERN, Geneva (Switzerland)

    2016-07-11

    Monte Carlo radiation transport codes are used by the CMS Beam Radiation Instrumentation and Luminosity (BRIL) project to estimate the radiation levels due to proton–proton collisions and machine induced background. Results are used by the CMS collaboration for various applications: comparison with detector hit rates, pile-up studies, predictions of radiation damage based on various models (Dose, NIEL, DPA), shielding design, estimations of residual dose environment. Simulation parameters, and the maintenance of the input files are summarized, and key results are presented. Furthermore, an overview of additional programs developed by the BRIL project to meet the specific needs of CMS community is given.

  1. Mars' surface radiation environment measured with the Mars Science Laboratory's Curiosity rover.

    Science.gov (United States)

    Hassler, Donald M; Zeitlin, Cary; Wimmer-Schweingruber, Robert F; Ehresmann, Bent; Rafkin, Scot; Eigenbrode, Jennifer L; Brinza, David E; Weigle, Gerald; Böttcher, Stephan; Böhm, Eckart; Burmeister, Soenke; Guo, Jingnan; Köhler, Jan; Martin, Cesar; Reitz, Guenther; Cucinotta, Francis A; Kim, Myung-Hee; Grinspoon, David; Bullock, Mark A; Posner, Arik; Gómez-Elvira, Javier; Vasavada, Ashwin; Grotzinger, John P

    2014-01-24

    The Radiation Assessment Detector (RAD) on the Mars Science Laboratory's Curiosity rover began making detailed measurements of the cosmic ray and energetic particle radiation environment on the surface of Mars on 7 August 2012. We report and discuss measurements of the absorbed dose and dose equivalent from galactic cosmic rays and solar energetic particles on the martian surface for ~300 days of observations during the current solar maximum. These measurements provide insight into the radiation hazards associated with a human mission to the surface of Mars and provide an anchor point with which to model the subsurface radiation environment, with implications for microbial survival times of any possible extant or past life, as well as for the preservation of potential organic biosignatures of the ancient martian environment.

  2. Bullying among radiation therapists: effects on job performance and work environment.

    Science.gov (United States)

    Trad, Megan; Johnson, Jordan

    2014-01-01

    To identify the effects of workplace bullying in the radiation therapy department on job performance and explore the environment and morale of individuals who work with a bully. A quantitative research study was designed to assess the prevalence and effects of bullying in the radiation therapy workplace. A total of 308 radiation therapists participated in the study for a return rate of 46%. Of those, 194 indicated that workplace bullying was present either in their current workplace or in a previous radiation therapy environment and that it negatively affected job performance and satisfaction. Findings of this study indicate a need for evaluation of the radiation therapy workplace, education on how to identify and prevent bullying behavior, and better communication among members of the radiation therapy environment. Participants indicated that working in a hostile environment led to forgetfulness, ineffective communication, and perceived discrepancies in promotion and treatment by management. Any bullying behavior contributes to an overall toxic work environment, which is unhealthy and unsafe for patients and therapists. Those who manage therapists should promote a culture of safety and embrace their staff's independence.

  3. Analysis of the solar radiation data for Beer Sheva, Israel, and its environs

    Energy Technology Data Exchange (ETDEWEB)

    Kudish, A.I. (Ben-Gurion Univ. of the Negev, Beer Sheva (Israel)); Ianetz, A. (Israel Meteorological Service, Bet-Dagan (Israel))

    1992-01-01

    The solar radiation climate of Beer Sheva, Israel, is reported upon in detail. The database utilized in this analysis consisted of global radiation on a horizontal surface, normal incidence beam radiation, and global radiation on a south-facing surface tilted at 40{degree}. Monthly-average hourly and daily values are reported for each of these three types of measured radiations, together with the calculated monthly-average daily values for the components of the global radiation, viz. the horizontal beam and diffuse radiations. The monthly-average hourly and daily clearness index values have also been calculated and analyzed. Monthly-average daily frequency distributions of the clearness index values are reported for each month. The solar radiation climate of Beer Sheva has also been compared to those reported for a number of countries in this region. The annual-average daily global radiation incident on a horizontal surface is 18.91 MG/m{sup 2} and that for normal incidence beam radiation is 21.17 MG/m{sup 2}. The annual-average daily fraction of the horizontal global radiation that is beam is 0.72. The annual-average daily value for the clearness index is 0.587 and the average frequency of clear days annually is 58.6%. The authors conclude, based upon the above analysis, that Beer Sheva and its environs are characterized by relatively high, average-daily irradiation rates, both global and beam, and a relatively high frequency of clear days.

  4. Radiation Safety Management Guidelines for PET-CT: Focus on Behavior and Environment

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jin Wook [Cancer Imaging Center, National University Cancer Hospital, Seoul (Korea, Republic of); Han, Eun Ok [Dept. of Radiological Technology, Daegu Health College, Seoul (Korea, Republic of)

    2011-09-15

    Our purpose is to specify behavior and environmental factors aimed at reducing the exposed dosage caused by PET-CT and to develop radiation safety management guidelines adequate for domestic circumstances. We have used a multistep-multimethod as the methodological approach to design and to carry out the research both in quality and quantity, including an analysis on previous studies, professional consultations and a survey. The survey includes responses from 139 practitioners in charged of 109 PET-CTs installed throughout Korea(reported by the Korean Society of Nuclear Medicine, 2010). The research use 156 questions using Cronbach's {alpha} (alpha) coefficients which were: 0.818 for 'the necessity of setting and installing the radiation protective environment'; 0.916 for 'the necessity of radiation protection', 'setting and installing the radiation protective environment'; and 0.885 for 'radiation protection'. The check list, derived from the radiation safety management guidelines focused on behavior and environment, was composed of 20 items for the radiation protective environment: including 5 items for the patient; 4 items for the guardian; 3 items for the radiologist; and 8 items applied to everyone involved; for a total of 26 items for the radiation protective behavior including: 12 items for the patient; 1 item for the guardian, 7 items for the radiologist; and 6 items applied to everyone involved. The specific check list is shown in (Table 5-6). Since our country has no safety management guidelines of its own to reduce the exposed dosage caused by PET-CTs, we believe the guidelines developed through this study means great deal to the field as it is not only appropriate for domestic circumstances, but also contains specific check lists for each target who may be exposed to radiation in regards to behavior and environment.

  5. On-site radiated emissions measurements in Semi-reverberant environments

    NARCIS (Netherlands)

    Vogt-Ardatjew, Robert; Lundgren, Urban; Fernandez-Romero, Sergio; Leferink, Frank

    2016-01-01

    Radiated emission tests are generally performed in either free space, reflection-free environments, such as an open area test site or semi- or full-anechoic chambers, or in reverberation chambers. This paper describes measurements in semireflecting environments such as an office, a workshop of a lar

  6. Inclusion of Radiation Environment Variability in Total Dose Hardness Assurance Methodology

    Science.gov (United States)

    Xapsos, M. A.; Stauffer, C.; Phan, A.; McClure, S. S.; Ladbury, R. L.; Pellish, J. A.; Campola, M. J.; LaBel, K. A.

    2015-01-01

    Variability of the space radiation environment is investigated with regard to parts categorization for total dose hardness assurance methods. It is shown that it can have a significant impact. A modified approach is developed that uses current environment models more consistently and replaces the design margin concept with one of failure probability.

  7. Using Space Weather Variability in Evaluating the Radiation Environment Design Specifications for NASA's Constellation Program

    Science.gov (United States)

    Coffey, Victoria N.; Blackwell, William C.; Minow, Joseph I.; Bruce, Margaret B.; Howard, James W.

    2007-01-01

    NASA's Constellation program, initiated to fulfill the Vision for Space Exploration, will create a new generation of vehicles for servicing low Earth orbit, the Moon, and beyond. Space radiation specifications for space system hardware are necessarily conservative to assure system robustness for a wide range of space environments. Spectral models of solar particle events and trapped radiation belt environments are used to develop the design requirements for estimating total ionizing radiation dose, displacement damage, and single event effects for Constellation hardware. We first describe the rationale using the spectra chosen to establish the total dose and single event design environmental specifications for Constellation systems. We then compare variability of the space environment to the spectral design models to evaluate their applicability as conservative design environments and potential vulnerabilities to extreme space weather events

  8. Radiation therapists' and radiation oncology medical physicists' perceptions of work and the working environment in Australia: a qualitative study.

    Science.gov (United States)

    Halkett, G K B; McKay, J; Hegney, D G; Breen, Lauren J; Berg, M; Ebert, M A; Davis, M; Kearvell, R

    2016-05-05

    Workforce recruitment and retention are issues in radiation oncology. The working environment is likely to have an impact on retention; however, there is a lack of research in this area. The objectives of this study were to: investigate radiation therapists' (RTs) and radiation oncology medical physicists' (ROMPs) perceptions of work and the working environment; and determine the factors that influence the ability of RTs and ROMPs to undertake their work and how these factors affect recruitment and retention. Semi-structured interviews were conducted and thematic analysis was used. Twenty-eight RTs and 21 ROMPs participated. The overarching themes were delivering care, support in work, working conditions and lifestyle. The overarching themes were mostly consistent across both groups; however, the exemplars reflected the different roles and perspectives of RTs and ROMPs. Participants described the importance they placed on treating patients and improving their lives. Working conditions were sometimes difficult with participants reporting pressure at work, large workloads and longer hours and overtime. Insufficient staff numbers impacted on the effectiveness of staff, the working environment and intentions to stay. Staff satisfaction is likely to be improved if changes are made to the working environment. We make recommendations that may assist departments to support RTs and ROMPs.

  9. Low-radiation environment affects the development of protection mechanisms in V79 cells.

    Science.gov (United States)

    Fratini, E; Carbone, C; Capece, D; Esposito, G; Simone, G; Tabocchini, M A; Tomasi, M; Belli, M; Satta, L

    2015-05-01

    Very little is known about the influence of environmental radiation on living matter. In principle, important information can be acquired by analysing possible differences between parallel biological systems, one in a reference-radiation environment (RRE) and the other in a low-radiation environment (LRE). We took advantage of the unique opportunity represented by the cell culture facilities at the Gran Sasso National Laboratories of the Istituto Nazionale di Fisica Nucleare, where environment dose rate reduction factors in the underground (LRE), with respect to the external laboratory (RRE), are as follows: 10(3) for neutrons, 10(7) for directly ionizing cosmic rays and 10 for total γ-rays. Chinese hamster V79 cells were cultured for 10 months in both RRE and LRE. At the end of this period, all the cultures were kept in RRE for another 6 months. Changes in the activities of antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPX) and spontaneous mutation frequency at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus were investigated. The results obtained suggest that environmental radiation might act as a trigger of defence mechanisms in V79 cells, specifically those in reference conditions, showing a higher degree of defence against endogenous damage as compared to cells grown in a very low-radiation environment. Our findings corroborate the hypothesis that environmental radiation contributes to the development of defence mechanisms in today living organisms/systems.

  10. Hardening electronic devices against very high total dose radiation environments

    Science.gov (United States)

    Buchanan, B.; Shedd, W.; Roosild, S.; Dolan, R.

    1972-01-01

    The possibilities and limitations of hardening silicon semiconductor devices to the high neutron and gamma radiation levels and greater than 10 to the eighth power rads required for the NERVA nuclear engine development are discussed. A comparison is made of the high dose neutron and gamma hardening potential of bipolar, metal insulator semiconductors and junction field effect transistors. Experimental data is presented on device degradation for the high neutron and gamma doses. Previous data and comparisons indicate that the JFET is much more immune to the combined neutron displacement and gamma ionizing effects than other transistor types. Experimental evidence is also presented which indicates that p channel MOS devices may be able to meet the requirements.

  11. The Los Alamos dynamic radiation environment assimilation model (DREAM) for space weather specification and forecasting

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, Geoffrey D [Los Alamos National Laboratory; Friedel, Reiner H W [Los Alamos National Laboratory; Chen, Yue [Los Alamos National Laboratory; Koller, Josef [Los Alamos National Laboratory; Henderson, Michael G [Los Alamos National Laboratory

    2008-01-01

    The Dynamic Radiation Environment Assimilation Model (DREAM) was developed at Los Alamos National Laboratory to assess, quantify, and predict the hazards from the natural space environment and the anthropogenic environment produced by high altitude nuclear explosions (HANE). DREAM was initially developed as a basic research activity to understand and predict the dynamics of the Earth's Van Allen radiation belts. It uses Kalman filter techniques to assimilate data from space environment instruments with a physics-based model of the radiation belts. DREAM can assimilate data from a variety of types of instruments and data with various levels of resolution and fidelity by assigning appropriate uncertainties to the observations. Data from any spacecraft orbit can be assimilated but DREAM was designed to function with as few as two spacecraft inputs: one from geosynchronous orbit and one from GPS orbit. With those inputs, DREAM can be used to predict the environment at any satellite in any orbit whether space environment data are available in those orbits or not. Even with very limited data input and relatively simple physics models, DREAM specifies the space environment in the radiation belts to a high level of accuracy. DREAM has been extensively tested and evaluated as we transition from research to operations. We report here on one set of test results in which we predict the environment in a highly-elliptical polar orbit. We also discuss long-duration reanalysis for spacecraft design, using DREAM for real-time operations, and prospects for 1-week forecasts of the radiation belt environment.

  12. Methodology for estimating radiation dose rates to freshwater biota exposed to radionuclides in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Blaylock, B.G.; Frank, M.L.; O`Neal, B.R.

    1993-08-01

    The purpose of this report is to present a methodology for evaluating the potential for aquatic biota to incur effects from exposure to chronic low-level radiation in the environment. Aquatic organisms inhabiting an environment contaminated with radioactivity receive external radiation from radionuclides in water, sediment, and from other biota such as vegetation. Aquatic organisms receive internal radiation from radionuclides ingested via food and water and, in some cases, from radionuclides absorbed through the skin and respiratory organs. Dose rate equations, which have been developed previously, are presented for estimating the radiation dose rate to representative aquatic organisms from alpha, beta, and gamma irradiation from external and internal sources. Tables containing parameter values for calculating radiation doses from selected alpha, beta, and gamma emitters are presented in the appendix to facilitate dose rate calculations. The risk of detrimental effects to aquatic biota from radiation exposure is evaluated by comparing the calculated radiation dose rate to biota to the U.S. Department of Energy`s (DOE`s) recommended dose rate limit of 0.4 mGy h{sup {minus}1} (1 rad d{sup {minus}1}). A dose rate no greater than 0.4 mGy h{sup {minus}1} to the most sensitive organisms should ensure the protection of populations of aquatic organisms. DOE`s recommended dose rate is based on a number of published reviews on the effects of radiation on aquatic organisms that are summarized in the National Council on Radiation Protection and Measurements Report No. 109 (NCRP 1991). DOE recommends that if the results of radiological models or dosimetric measurements indicate that a radiation dose rate of 0. 1 mGy h{sup {minus}1} will be exceeded, then a more detailed evaluation of the potential ecological consequences of radiation exposure to endemic populations should be conducted.

  13. Methodology for estimating radiation dose rates to freshwater biota exposed to radionuclides in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Blaylock, B.G.; Frank, M.L.; O`Neal, B.R.

    1993-08-01

    The purpose of this report is to present a methodology for evaluating the potential for aquatic biota to incur effects from exposure to chronic low-level radiation in the environment. Aquatic organisms inhabiting an environment contaminated with radioactivity receive external radiation from radionuclides in water, sediment, and from other biota such as vegetation. Aquatic organisms receive internal radiation from radionuclides ingested via food and water and, in some cases, from radionuclides absorbed through the skin and respiratory organs. Dose rate equations, which have been developed previously, are presented for estimating the radiation dose rate to representative aquatic organisms from alpha, beta, and gamma irradiation from external and internal sources. Tables containing parameter values for calculating radiation doses from selected alpha, beta, and gamma emitters are presented in the appendix to facilitate dose rate calculations. The risk of detrimental effects to aquatic biota from radiation exposure is evaluated by comparing the calculated radiation dose rate to biota to the U.S. Department of Energy`s (DOE`s) recommended dose rate limit of 0.4 mGy h{sup {minus}1} (1 rad d{sup {minus}1}). A dose rate no greater than 0.4 mGy h{sup {minus}1} to the most sensitive organisms should ensure the protection of populations of aquatic organisms. DOE`s recommended dose rate is based on a number of published reviews on the effects of radiation on aquatic organisms that are summarized in the National Council on Radiation Protection and Measurements Report No. 109 (NCRP 1991). DOE recommends that if the results of radiological models or dosimetric measurements indicate that a radiation dose rate of 0. 1 mGy h{sup {minus}1} will be exceeded, then a more detailed evaluation of the potential ecological consequences of radiation exposure to endemic populations should be conducted.

  14. Radiation Protection of Environment under the Light of the New Concept of Radiation Protection of Non-Human Species

    Energy Technology Data Exchange (ETDEWEB)

    Hansruedi Voelkle [Swiss Federal Office of Public Health, Environmental Radioactivity Section, c/o Physics Department, University of Fribourg Chemin du Musee 3, 1700 Fribourg (Switzerland)

    2006-07-01

    The purpose of this presentation is to discuss the question of whether radiation protection should be extended to plants and animals. Until now the recommendations of ICRP have been focused exclusively on the protection of man from ionizing radiation. It was assumed that, if man is protected, the quality of the living environment is not impaired. In recent years adequate principles, recommendations and laws have become necessary in order to protect the environment from man made toxins. These recommendations aimed to conserve plants and animals, to maintain the diversity of species, the health and status of natural habitats and the natural resources of our planet, to warrant natural evolution and selection processes in order to transmit a healthy world to future generations. Reflections have been made as to whether particular protection of fauna and flora from ionizing radiation should be included. This article presents some considerations from the point of view of operational radiation protection and some comments to the work already done by ICRP committee 5. The final purpose is to invite the audience to make its own reflections and to communicate any criticisms, comments or suggestions to committee 5 of ICRP. (author)

  15. A Monte Carlo transport code study of the space radiation environment using FLUKA and ROOT

    CERN Document Server

    Wilson, T; Carminati, F; Brun, R; Ferrari, A; Sala, P; Empl, A; MacGibbon, J

    2001-01-01

    We report on the progress of a current study aimed at developing a state-of-the-art Monte-Carlo computer simulation of the space radiation environment using advanced computer software techniques recently available at CERN, the European Laboratory for Particle Physics in Geneva, Switzerland. By taking the next-generation computer software appearing at CERN and adapting it to known problems in the implementation of space exploration strategies, this research is identifying changes necessary to bring these two advanced technologies together. The radiation transport tool being developed is tailored to the problem of taking measured space radiation fluxes impinging on the geometry of any particular spacecraft or planetary habitat and simulating the evolution of that flux through an accurate model of the spacecraft material. The simulation uses the latest known results in low-energy and high-energy physics. The output is a prediction of the detailed nature of the radiation environment experienced in space as well a...

  16. Using Space Weather Variability in Evaluation the Radiation Environment Specifications for NASA's Constellation Program

    Science.gov (United States)

    Coffey, Victoria N.; Minow, Joseph I.; Bruce, Margaret; Howard, James W.

    2008-01-01

    Hardware design environments for NASA's Constellation Program-the Vision for Space Exploration program to design and build new vehicles for servicing low Earth orbit and the Moon and beyond-have been developed that are necessarily conservative in nature to assure robust hardware design and development required to build space systems which will meet operational goals in a wide range of space environments, This presentation will describe the rationale used to establish the space radiation and plasma design environments specified for a variety of applications including total ionizing radiation dose, dose rate effects, and spacecraft charging and will compare the design environments with "space weather" variability to evaluate the applicability of the design environments and potential vulnerabilities of the system to extreme space weather events.

  17. The Ultraviolet Radiation Environment Around M dwarf Exoplanet Host Stars

    CERN Document Server

    France, Kevin; Linsky, Jeffrey L; Roberge, Aki; Stocke, John T; Tian, Feng; Bushinsky, Rachel; Desert, Jean-Michel; Mauas, Pablo; Vieytes, Mariela; Walkowicz, Lucianne M

    2012-01-01

    The spectral and temporal behavior of exoplanet host stars is a critical input to models of the chemistry and evolution of planetary atmospheres. At present, little observational or theoretical basis exists for understanding the ultraviolet spectra of M dwarfs, despite their critical importance to predicting and interpreting the spectra of potentially habitable planets as they are obtained in the coming decades. Using observations from the Hubble Space Telescope, we present a study of the UV radiation fields around nearby M dwarf planet hosts that covers both FUV and NUV wavelengths. The combined FUV+NUV spectra are publically available in machine-readable format. We find that all six exoplanet host stars in our sample (GJ 581, GJ 876, GJ 436, GJ 832, GJ 667C, and GJ 1214) exhibit some level of chromospheric and transition region UV emission. No "UV quiet" M dwarfs are observed. The bright stellar Ly-alpha emission lines are reconstructed, and we find that the Ly-alpha line fluxes comprise ~37-75% of the tota...

  18. Modeling Background Radiation in our Environment Using Geochemical Data

    Energy Technology Data Exchange (ETDEWEB)

    Malchow, Russell L.; Marsac, Kara [University of Nevada, Las Vegas; Burnley, Pamela [University of Nevada, Las Vegas; Hausrath, Elisabeth [Uniiversity of Nevada, Las Vegas; Haber, Daniel [University of Nevada, Las Vegas; Adcock, Christopher [University of Nevada, Las Vegas

    2015-02-01

    Radiation occurs naturally in bedrock and soil. Gamma rays are released from the decay of the radioactive isotopes K, U, and Th. Gamma rays observed at the surface come from the first 30 cm of rock and soil. The energy of gamma rays is specific to each isotope, allowing identification. For this research, data was collected from national databases, private companies, scientific literature, and field work. Data points were then evaluated for self-consistency. A model was created by converting concentrations of U, K, and Th for each rock and soil unit into a ground exposure rate using the following equation: D=1.32 K+ 0.548 U+ 0.272 Th. The first objective of this research was to compare the original Aerial Measurement System gamma ray survey to results produced by the model. The second objective was to improve the method and learn the constraints of the model. Future work will include sample data analysis from field work with a goal of improving the geochemical model.

  19. A study on the life extension of polymer materials under radiation environment

    Energy Technology Data Exchange (ETDEWEB)

    Park, K. J.; Park, S. W.; Cho, S. H.; Hong, S. S

    2000-12-01

    The object of this study is to improve the stability and the economic profit by reducing the radiation-induced degradation rate of polymer material used under the radiation environment. So far, the resistance to radiation-induced oxidation of a polymer has been improved by the stabilizers. They can play an important role in the anti-oxidants that interrupt the radical-mediated oxidation chain reaction. The stabilization effect could be larger than that achieved in an inert-atmosphere irradiation. Stabilization is a function of stabilizer concentration up to a certain threshold, but it is not further improved above this concentration. Beyond the threshold, the rate of radiation-induced oxidation goes up to the rate that is characteristic for the unstabilized polymer. To make up for this weakness, a technique depositing a thin layer of diamond-like carbon (DLC) on the polymer surface was developed for protecting the radiation-induced oxidation in the air.

  20. Interactive Visual Intervention Planning: Interactive Visualization for Intervention Planning in Particle Accelerator Environments with Ionizing Radiation

    CERN Document Server

    Fabry, Thomas; Feral, Bruno

    2013-01-01

    Intervention planning is crucial for maintenance operations in particle accelerator environments with ionizing radiation, during which the radiation dose contracted by maintenance workers should be reduced to a minimum. In this context, we discuss the visualization aspects of a new software tool, which integrates interactive exploration of a scene depicting an accelerator facility augmented with residual radiation level simulations, with the visualization of intervention data such as the followed trajectory and maintenance tasks. The visualization of each of these aspects has its effect on the final predicted contracted radiation dose. In this context, we explore the possible benefits of a user study, with the goal of enhancing the visual conditions in which the intervention planner using the software tool is minimizing the radiation dose.

  1. Experimental investigation of the radiation shielding of a MCP detector in the radiation environment near Europa

    Science.gov (United States)

    Tulej, Marek; Wurz, Peter; Meyer, Stefan; Lasi, Davide; Lüthi, Matthias; Galli, André; Piazza, Daniele; Desorgher, Laurent; Hajdas, Wojciech; Reggiani, Davide; Karlsson, Stefan; Kalla, Leif

    2016-04-01

    The Neutral Ion Mass spectrometer (NIM) is one of the six instruments in the Particle Environmental Package (PEP) designed for the JUICE mission of ESA to the Jupiter system. NIM will conduct detailed measurements of chemical composition of Jovian moon exospheres and is equipped with a sensitive MCP ion detector. To maintain high sensitivity of the NIM instrument, background signals arising from the presence of a large background of penetrating radiation (mostly high-energy electrons and protons) in Jupiter's magnetosphere have to be minimised. We investigate the performance of a layered-Z radiation shield, an Al-Ta-Al sandwich, as a potential shielding against high-energy electrons. The experimental investigations were performed at the PiM1 beam line of the High Intensity Proton Accelerator Facilities located at the Paul Scherrer Institute (PSI), Villigen, Switzerland. The facility delivers a particle beam containing e,  and  with an adjustable momentum ranging from 17.5 to 345 MeV/c. The measurements of the induced radiation background generated during the interaction of primary particles with Al-Ta-Al sandwich were conducted by beam diagnostic methods and a MCP detector. Diagnostic methods provided for the characterisation of the beam parameters (beam geometry, flux and intensity) and identification of individual particles in the primary beam and in the flux of secondary particles. The MCP detector measurements provided information on the effects of radiation and the results of these measurements define the performance of the shielding material in reducing the background arising from penetrating radiation. In parallel, we performed modelling studies using GEANT 4 and GRASS methods to identify products of the interaction and predict their fluxes and particle rates at the MCP detector. Combination of the experiment and modelling studies yields detailed characterisation of the radiation effects produced by the interaction of the incident e- in the

  2. THE ULTRAVIOLET RADIATION ENVIRONMENT AROUND M DWARF EXOPLANET HOST STARS

    Energy Technology Data Exchange (ETDEWEB)

    France, Kevin; Froning, Cynthia S.; Stocke, John T.; Bushinsky, Rachel [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Linsky, Jeffrey L. [JILA, University of Colorado and NIST, 440 UCB, Boulder, CO 80309 (United States); Roberge, Aki [Exoplanets and Stellar Astrophysics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Tian, Feng [Center for Earth System Sciences, Tsinghua University, Beijing 100084 (China); Desert, Jean-Michel [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Mauas, Pablo; Vieytes, Mariela [Instituto de Astronomsica del Espacio (CONICET-UBA), C.C. 67 Sucursal 28, 1428 Buenos Aires (Argentina); Walkowicz, Lucianne M., E-mail: kevin.france@colorado.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2013-02-15

    The spectral and temporal behavior of exoplanet host stars is a critical input to models of the chemistry and evolution of planetary atmospheres. Ultraviolet photons influence the atmospheric temperature profiles and production of potential biomarkers on Earth-like planets around these stars. At present, little observational or theoretical basis exists for understanding the ultraviolet spectra of M dwarfs, despite their critical importance to predicting and interpreting the spectra of potentially habitable planets as they are obtained in the coming decades. Using observations from the Hubble Space Telescope, we present a study of the UV radiation fields around nearby M dwarf planet hosts that covers both far-UV (FUV) and near-UV (NUV) wavelengths. The combined FUV+NUV spectra are publicly available in machine-readable format. We find that all six exoplanet host stars in our sample (GJ 581, GJ 876, GJ 436, GJ 832, GJ 667C, and GJ 1214) exhibit some level of chromospheric and transition region UV emission. No 'UV-quiet' M dwarfs are observed. The bright stellar Ly{alpha} emission lines are reconstructed, and we find that the Ly{alpha} line fluxes comprise {approx}37%-75% of the total 1150-3100 A flux from most M dwarfs; {approx}>10{sup 3} times the solar value. We develop an empirical scaling relation between Ly{alpha} and Mg II emission, to be used when interstellar H I attenuation precludes the direct observation of Ly{alpha}. The intrinsic unreddened flux ratio is F(Ly{alpha})/F(Mg II) = 10 {+-} 3. The F(FUV)/F(NUV) flux ratio, a driver for abiotic production of the suggested biomarkers O{sub 2} and O{sub 3}, is shown to be {approx}0.5-3 for all M dwarfs in our sample, >10{sup 3} times the solar ratio. For the four stars with moderate signal-to-noise Cosmic Origins Spectrograph time-resolved spectra, we find UV emission line variability with amplitudes of 50%-500% on 10{sup 2}-10{sup 3} s timescales. This effect should be taken into account in future UV

  3. The Ultraviolet Radiation Environment around M Dwarf Exoplanet Host Stars

    Science.gov (United States)

    France, Kevin; Froning, Cynthia S.; Linsky, Jeffrey L.; Roberge, Aki; Stocke, John T.; Tian, Feng; Bushinsky, Rachel; Desert, Jean-Michel; Mauas, Pablo; Mauas, Pablo; Walkowicz, Lucianne M.

    2013-01-01

    The spectral and temporal behavior of exoplanet host stars is a critical input to models of the chemistry and evolution of planetary atmospheres. Ultraviolet photons influence the atmospheric temperature profiles and production of potential biomarkers on Earth-like planets around these stars. At present, little observational or theoretical basis exists for understanding the ultraviolet spectra of M dwarfs, despite their critical importance to predicting and interpreting the spectra of potentially habitable planets as they are obtained in the coming decades. Using observations from the Hubble Space Telescope, we present a study of the UV radiation fields around nearby M dwarf planet hosts that covers both far-UV (FUV) and near-UV (NUV) wavelengths. The combined FUV+NUV spectra are publicly available in machine-readable format. We find that all six exoplanet host stars in our sample (GJ 581, GJ 876, GJ 436, GJ 832, GJ 667C, and GJ 1214) exhibit some level of chromospheric and transition region UV emission. No "UV-quiet" M dwarfs are observed. The bright stellar Lyman-alpha emission lines are reconstructed, and we find that the Lyman-alpha line fluxes comprise approximately 37%-75% of the total 1150-3100 A flux from most M dwarfs; approximately greater than 10(exp3) times the solar value. We develop an empirical scaling relation between Lyman-alpha and Mg II emission, to be used when interstellar H I attenuation precludes the direct observation of Lyman-alpha. The intrinsic unreddened flux ratio is F(Lyman-alpha)/F(Mg II) = 10(exp3). The F(FUV)/F(NUV) flux ratio, a driver for abiotic production of the suggested biomarkers O2 and O3, is shown to be approximately 0.5-3 for all M dwarfs in our sample, greather than 10(exp3) times the solar ratio. For the four stars with moderate signal-to-noise Cosmic Origins Spectrograph time-resolved spectra, we find UV emission line variability with amplitudes of 50%.500% on 10(exp2)-10(exp3) s timescales. This effect should be taken

  4. Degradation mechanisms of cable insulation materials during radiation-thermal ageing in radiation environment

    Science.gov (United States)

    Seguchi, Tadao; Tamura, Kiyotoshi; Ohshima, Takeshi; Shimada, Akihiko; Kudoh, Hisaaki

    2011-02-01

    Radiation and thermal degradation of ethylene-propylene rubber (EPR) and crosslinked polyethylene (XLPE) as cable insulation materials were investigated by evaluating tensile properties, gel-fraction, and swelling ratio, as well as by the infrared (FTIR) analysis. The activation energy of thermal oxidative degradation changed over the range 100-120 °C for both EPR and XLPE. This may be attributed to the fact that the content of an antioxidant used as the stabilizer for polymers decreases by evaporation during thermal ageing at high temperatures. The analysis of antioxidant content and oxidative products in XLPE as a model sample showed that a small amount of antioxidant significantly reduced the extent of thermal oxidation, but was not effective for radiation induced oxidation. The changes in mechanical properties were well reflected by the degree of oxidation. A new model of polymer degradation mechanisms was proposed where the degradation does not take place by chain reaction via peroxy radical and hydro-peroxide. The role of the antioxidant in the polymer is the reduction of free radical formation in the initiation step in thermal oxidation, and it could not stop radical reactions for either radiation or thermal oxidation.

  5. Degradation mechanisms of cable insulation materials during radiation-thermal ageing in radiation environment

    Energy Technology Data Exchange (ETDEWEB)

    Seguchi, Tadao, E-mail: seguchi@aj.wakwak.co [Japan Atomic Energy Agency, Tokai 319-1195 (Japan); Tamura, Kiyotoshi; Ohshima, Takeshi; Shimada, Akihiko [Japan Atomic Energy Agency, Tokai 319-1195 (Japan); Kudoh, Hisaaki [University of Tokyo, Tokai 319-1195 (Japan)

    2011-02-15

    Radiation and thermal degradation of ethylene-propylene rubber (EPR) and crosslinked polyethylene (XLPE) as cable insulation materials were investigated by evaluating tensile properties, gel-fraction, and swelling ratio, as well as by the infrared (FTIR) analysis. The activation energy of thermal oxidative degradation changed over the range 100-120 {sup o}C for both EPR and XLPE. This may be attributed to the fact that the content of an antioxidant used as the stabilizer for polymers decreases by evaporation during thermal ageing at high temperatures. The analysis of antioxidant content and oxidative products in XLPE as a model sample showed that a small amount of antioxidant significantly reduced the extent of thermal oxidation, but was not effective for radiation induced oxidation. The changes in mechanical properties were well reflected by the degree of oxidation. A new model of polymer degradation mechanisms was proposed where the degradation does not take place by chain reaction via peroxy radical and hydro-peroxide. The role of the antioxidant in the polymer is the reduction of free radical formation in the initiation step in thermal oxidation, and it could not stop radical reactions for either radiation or thermal oxidation.

  6. PABLM: a computer program to calculate accumulated radiation doses from radionuclides in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Napier, B.A.; Kennedy, W.E. Jr.; Soldat, J.K.

    1980-03-01

    A computer program, PABLM, was written to facilitate the calculation of internal radiation doses to man from radionuclides in food products and external radiation doses from radionuclides in the environment. This report contains details of mathematical models used and calculational procedures required to run the computer program. Radiation doses from radionuclides in the environment may be calculated from deposition on the soil or plants during an atmospheric or liquid release, or from exposure to residual radionuclides in the environment after the releases have ended. Radioactive decay is considered during the release of radionuclides, after they are deposited on the plants or ground, and during holdup of food after harvest. The radiation dose models consider several exposure pathways. Doses may be calculated for either a maximum-exposed individual or for a population group. The doses calculated are accumulated doses from continuous chronic exposure. A first-year committed dose is calculated as well as an integrated dose for a selected number of years. The equations for calculating internal radiation doses are derived from those given by the International Commission on Radiological Protection (ICRP) for body burdens and MPC's of each radionuclide. The radiation doses from external exposure to contaminated water and soil are calculated using the basic assumption that the contaminated medium is large enough to be considered an infinite volume or plane relative to the range of the emitted radiations. The equations for calculations of the radiation dose from external exposure to shoreline sediments include a correction for the finite width of the contaminated beach.

  7. Approach to reducing the effect of bone-coal power station on radiation environment

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The effect of two bone-coal power stations (6 MWe) on environment wasinvestigated within the scope of the dose contribution caused by various radionucildes in different ways. It is found that the best measures to reduce the effect of bone-coal power station on radiation environment include to select a fine boiler system and a comprehensive utilization of the bone-coal cinder (BCC), soot and ash in the catchers.

  8. Approach to reducing the effect of bone—coal power station on radiation environment

    Institute of Scientific and Technical Information of China (English)

    NIShi-Ying; GUPei-Long; 等

    2002-01-01

    The effect of two bone-coal power stations(6MWe) on environment was investigated within the scope of the dose contribution caused by various radionucildes in different ways.It is found that the best measures to reduce the effect of bone-coal power station on radiation environment include to select a fine boiler system and a comprehensive utilization of the bone-coal cinder(BCC),soot and ash in the catchers.

  9. Experimental Characterization of a Composite Morphing Radiator Prototype in a Relevant Thermal Environment

    Science.gov (United States)

    Bertagne, Christopher L.; Chong, Jorge B.; Whitcomb, John D.; Hartl, Darren J.; Erickson, Lisa R.

    2017-01-01

    For future long duration space missions, crewed vehicles will require advanced thermal control systems to maintain a desired internal environment temperature in spite of a large range of internal and external heat loads. Current radiators are only able to achieve turndown ratios (i.e. the ratio between the radiator's maximum and minimum heat rejection rates) of approximately 3:1. Upcoming missions will require radiators capable of 12:1 turndown ratios. A radiator with the ability to alter shape could significantly increase turndown capacity. Shape memory alloys (SMAs) offer promising qualities for this endeavor, namely their temperature-dependent phase change and capacity for work. In 2015, the first ever morphing radiator prototype was constructed in which SMA actuators passively altered the radiator shape in response to a thermal load. This work describes a follow-on endeavor to demonstrate a similar concept using highly thermally conductive composite materials. Numerous versions of this new concept were tested in a thermal vacuum environment and successfully demonstrated morphing behavior and variable heat rejection, achieving a turndown ratio of 4.84:1. A summary of these thermal experiments and their results are provided herein.

  10. Radiation protection of the environment: anthropocentric and eco-centric principles

    Energy Technology Data Exchange (ETDEWEB)

    Alexakhin, R.M.; Fesenko, S.V. [Russian Institute of Agricultural Radiology and Agroecology, RAAS, Obninsk (Russian Federation)

    2004-07-01

    The second half of the 20. century was dominated in the field of radiation protection by the anthropocentric concept stated by the International Commission on Radiological Protection (ICRP). According to this concept 'if radiation standards protect man then biota are also adequately protected from ionizing radiation'. At the end of the 20. beginning of the 21. centuries in the area of radiation protection of nature an eco-centric strategy is beginning to develop where emphasis has swung to the protection of biota in their environment. Inadequacy of ICRP's anthropocentric concept is reported. Issues are discussed such as ecological dosimetry, non-equi-dose irradiation of man and biota, criteria for estimating radiation induced changes in biota and man, as well as the need to harmonize permissible exposure doses to man and biota. An urgent need is stressed to develop a single (synthetic) concept of radiation protection which simultaneously ensures protection of human health and biota well-being in their environment. This concept is to be based on the recognition of the integrity of socio-natural ecosystems where man and biota are considered as a unity. (author)

  11. The Martian surface radiation environment – a comparison of models and MSL/RAD measurements

    Directory of Open Access Journals (Sweden)

    Matthiä Daniel

    2016-01-01

    Full Text Available Context: The Radiation Assessment Detector (RAD on the Mars Science Laboratory (MSL has been measuring the radiation environment on the surface of Mars since August 6th 2012. MSL-RAD is the first instrument to provide detailed information about charged and neutral particle spectra and dose rates on the Martian surface, and one of the primary objectives of the RAD investigation is to help improve and validate current radiation transport models. Aims: Applying different numerical transport models with boundary conditions derived from the MSL-RAD environment the goal of this work was to both provide predictions for the particle spectra and the radiation exposure on the Martian surface complementing the RAD sensitive range and, at the same time, validate the results with the experimental data, where applicable. Such validated models can be used to predict dose rates for future manned missions as well as for performing shield optimization studies. Methods: Several particle transport models (GEANT4, PHITS, HZETRN/OLTARIS were used to predict the particle flux and the corresponding radiation environment caused by galactic cosmic radiation on Mars. From the calculated particle spectra the dose rates on the surface are estimated. Results: Calculations of particle spectra and dose rates induced by galactic cosmic radiation on the Martian surface are presented. Although good agreement is found in many cases for the different transport codes, GEANT4, PHITS, and HZETRN/OLTARIS, some models still show large, sometimes order of magnitude discrepancies in certain particle spectra. We have found that RAD data is helping to make better choices of input parameters and physical models. Elements of these validated models can be applied to more detailed studies on how the radiation environment is influenced by solar modulation, Martian atmosphere and soil, and changes due to the Martian seasonal pressure cycle. By extending the range of the calculated particle

  12. Adaptive response in frogs chronically exposed to low doses of ionizing radiation in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Audette-Stuart, M., E-mail: stuartm@aecl.ca [Environmental Technologies Branch, Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, Ontario, K0J 1P0 (Canada); Kim, S.B.; McMullin, D.; Festarini, A.; Yankovich, T.L.; Carr, J.; Mulpuru, S. [Environmental Technologies Branch, Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, Ontario, K0J 1P0 (Canada)

    2011-06-15

    Using the micronucleus assay, decreased levels of DNA damage were found after high dose ionizing radiation exposure of liver cells taken from frogs inhabiting a natural environment with above-background levels of ionizing radiation, compared to cells taken from frogs inhabiting background areas. The data obtained from a small number of animals suggest that stress present in the above-background environment could induce an adaptive response to ionizing radiation. This study did not reveal harmful effects of exposure to low levels of radioactivity. On the contrary, stress present in the above-background area may serve to enhance cellular defense mechanisms. - Highlights: > Frogs were collected from background and higher tritium level habitats. > The micronucleus assay was conducted on liver cells obtained from the frogs. > No detrimental effects were noted in frogs exposed to elevated tritium. > Adaptive responses were observed in frogs exposed to elevated tritium.

  13. Radiation Impact to Environment of Non-nuclear Industry in Hunan,Hubei and Jiangxi Provinces

    Institute of Scientific and Technical Information of China (English)

    SONG; Wei-jie; CHENG; Wei-ya

    2015-01-01

    According to the gas,liquid effluent monitoring and survey results of non nuclear industry in Hunan,Hubei and Jiangxi provinces,the radiation effects of which on the surrounding environment were analysis and evaluation.Evaluation industrials includes three coal-fired power plants,two rare earth ores,two cement factories,one

  14. A Method for Estimating the Probability of Floating Gate Prompt Charge Loss in a Radiation Environment

    Science.gov (United States)

    Edmonds, L. D.

    2016-01-01

    Since advancing technology has been producing smaller structures in electronic circuits, the floating gates in modern flash memories are becoming susceptible to prompt charge loss from ionizing radiation environments found in space. A method for estimating the risk of a charge-loss event is given.

  15. Interactions of Changing Solar Ultraviolet Radiation and Climate with Light Induced Chemical Reactions in Aquatic Environments

    Science.gov (United States)

    Changes in the ozone layer over the past two decades have resulted in increases in solar ultraviolet radiation that reach the surface of North American aquatic environments. Concurrent changes in atmospheric CO2 are resulting in changes in stratification and precipitation that ar...

  16. Methodology for calculation of radiation doses in the environs from nuclear fuel cycle facilities

    Energy Technology Data Exchange (ETDEWEB)

    Soldat, J.K.

    1976-08-01

    Comparison of the impacts of various nuclear fuel cycle alternatives includes the evaluation of the radiological impacts. To evaluate the radiological impacts of fuel cycle alternatives, exposure to man must first be identified. The pathways of consequence by which man can be exposed to radiation from a nuclear facility are listed and are grouped into those associated with gaseous effluents, those associated with liquid effluents, and those involving exposure to direct radiation from the facility or from transportation of radioactive materials to or from the facility. Calculations for each pathway were made for those selected organs which could potentially receive the highest radiation dose. Some of the programs developed for calculating radiation doses from radionuclides in the environment are described. (CH)

  17. Electromagnetic and radiation environments: effects on pacemakers; Environnements electromagnetiques et radiatifs: effets sur les stimulateurs cardiaques

    Energy Technology Data Exchange (ETDEWEB)

    Mouton, J.; Trochet, R.; Vicrey, J.; Sauvage, M. [CEA Bruyeres-le-Chatel, 91 (France); Chauvenet, B.; Ostrovski, A.; Leroy, E. [Bureau National de Metrologie, LPRI, CEA Saclay, 91 - Gif-sur-Yvette (France); Haug, R. [Centre National de la Recherche Scientifique (CNRS), Lab. de Physique des Gaz et des Plasma, SUPELEC, 91 - Orsay (France); Dodinot, B. [Centre de Stimulation Cardiaque, CHU de Brabois, 54 - Vandoeuvre les Nancy (France); Joffre, F. [CEA Saclay, Dept. d' Electronique et d' Instrumentation Nucleaire, LETI, 91 - Gif-sur-Yvette (France)

    1999-07-01

    Nowadays, medical care development allows many people to share the benefits of implanted pacemakers (PM). PM can be perturbed and even fall in complete breakdowns in an electromagnetic and radiation environment. A stimuli-dependent patient can thus be seriously in danger. This article presents the effect of ionizing radiation from either a cobalt-60 source or from a linear accelerator (Saturne 43) on 12 pacemakers. It seems that technological progress make electronic circuits more sensitive to the cumulated dose of radiation. This survey shows that pacemakers have great difficulties to sustain ionizing radiation doses that are commonly delivered to patients during therapies. Usually perturbed functioning appears suddenly and means a strong shift of stimuli that might lead to heart failure.

  18. Systematics in the application of natural radiation environments to allowable launch burden and its distribution

    Science.gov (United States)

    Barengoltz, J.

    A central feature of the advanced planetary protection planning for missions to Europa is the credit for the reduction of the spacecraft microbial burden by the radiation belts of Jupiter. Although the United States National Aeronautics and Space Administration planetary protection program has not yet set requirements for missions to Europa, the Space Studies Board of the National Research Council has published guidelines. Whether the requirements will be the allowable probability of contamination of Europa or the allowable microbial burden at launch, it is reasonable to consider the natural radiation environment in the approach to compliance. The systematics of the analysis for the microbial reduction due to the proton and electron environments of Jupiter's radiation belts include: a "shielding" representation of the spacecraft; the external mission fluence spectra of each of the natural radiation environments for the mission trajectory; a radiation transport analysis in the "shielding" representation for each of the spectra; and established planetary protection specifications of appropriate classes of microbes and the D-values (dose for a one order of magnitude reduction in population) by protons and electrons for each class. The proton dose and the electron dose in discrete regions of the spacecraft, the "nodes" of the "shielding" representation, an intermediate product, is analogous to the design of shielding for the protection of the system electronics. The application of the D-values to determine a lethality factor at each node for each class of microbe is unique to planetary protection. From the outlined procedure, the relationship between the microbial population at launch and at Europa encounter (or after any specific trajectory in the Jupiter radiation environment) may be calculated. Details of this outline will be presented. The precedent of the shielding analysis for Project Galileo and the analogy to the thermal analysis for the Viking lander terminal

  19. Effects of ozone depletion and UV-B radiation on humans and the environment

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, K.R. [Guelph Univ., ON (Canada). Centre for Toxicology

    2008-03-15

    This paper summarized current research related to the effects of ultraviolet (UV-B) radiation on human health and the environment. Effects included direct responses in human as well as effects on biogeochemistry and the environmental cycling of substances. UV radiation has many harmful effects on the skin, eyes, and immune systems of humans. Skin cancer is a leading cause of death among fair-skinned populations exposed to UV radiation. The role of UV radiation in cataract formation was discussed, as well as issues related to the suppression of immune responses. The link between sunlight exposure and vitamin D levels in human populations was examined. The effects of UV radiation on terrestrial and aquatic ecosystems were reviewed. Issues related to biogeochemistry and atmospheric processes were discussed. The review suggested that changes in the intensity of solar UV radiation due to ozone depletion will have important repercussions for all organisms on the planet. It was concluded that the combined effects of UV-B radiation and climate change will not be easy to predict. 201 refs., 4 figs.

  20. Terrain and Radiation Mapping in Post-Disaster Environments Using an Autonomous Helicopter

    Directory of Open Access Journals (Sweden)

    Kevin Kochersberger

    2012-07-01

    Full Text Available Recent events have highlighted the need for unmanned remote sensing in dangerous areas, particularly where structures have collapsed or explosions have occurred, to limit hazards to first responders and increase their efficiency in planning response operations. In the case of the Fukushima nuclear reactor explosion, an unmanned helicopter capable of obtaining overhead images, gathering radiation measurements, and mapping both the structural and radiation content of the environment would have given the response team invaluable data early in the disaster, thereby allowing them to understand the extent of the damage and areas where dangers to personnel existed. With this motivation, the Unmanned Systems Lab at Virginia Tech has developed a remote sensing system for radiation detection and aerial imaging using a 90 kg autonomous helicopter and sensing payloads for the radiation detection and imaging operations. The radiation payload, which is the sensor of focus in this paper, consists of a scintillating type detector with associated software and novel search algorithms to rapidly and effectively map and locate sources of high radiation intensity. By incorporating this sensing technology into an unmanned aerial vehicle system, crucial situational awareness can be gathered about a post-disaster environment and response efforts can be expedited. This paper details the radiation mapping and localization capabilities of this system as well as the testing of the various search algorithms using simulated radiation data. The various components of the system have been flight tested over a several-year period and a new production flight platform has been built to enhance reliability and maintainability. The new system is based on the Aeroscout B1-100 helicopter platform, which has a one-hour flight endurance and uses a COFDM radio system that gives the helicopter an effective range of 7 km.

  1. Methodology for Estimating Radiation Dose Rates to Freshwater Biota Exposed to Radionuclides in the Environment

    Energy Technology Data Exchange (ETDEWEB)

    Blaylock, B.G.

    1993-01-01

    The purpose of this report is to present a methodology for evaluating the potential for aquatic biota to incur effects from exposure to chronic low-level radiation in the environment. Aquatic organisms inhabiting an environment contaminated with radioactivity receive external radiation from radionuclides in water, sediment, and from other biota such as vegetation. Aquatic organisms receive internal radiation from radionuclides ingested via food and water and, in some cases, from radionuclides absorbed through the skin and respiratory organs. Dose rate equations, which have been developed previously, are presented for estimating the radiation dose rate to representative aquatic organisms from alpha, beta, and gamma irradiation from external and internal sources. Tables containing parameter values for calculating radiation doses from selected alpha, beta, and gamma emitters are presented in the appendix to facilitate dose rate calculations. The risk of detrimental effects to aquatic biota from radiation exposure is evaluated by comparing the calculated radiation dose rate to biota to the U.S. Department of Energy's (DOE's) recommended dose rate limit of 0.4 mGy h{sup -1} (1 rad d{sup -1}). A dose rate no greater than 0.4 mGy h{sup -1} to the most sensitive organisms should ensure the protection of populations of aquatic organisms. DOE's recommended dose rate is based on a number of published reviews on the effects of radiation on aquatic organisms that are summarized in the National Council on Radiation Protection and Measurements Report No. 109 (NCRP 1991). The literature identifies the developing eggs and young of some species of teleost fish as the most radiosensitive organisms. DOE recommends that if the results of radiological models or dosimetric measurements indicate that a radiation dose rate of 0.1 mGy h{sup -1} will be exceeded, then a more detailed evaluation of the potential ecological consequences of radiation exposure to endemic

  2. Methodology for Estimating Radiation Dose Rates to Freshwater Biota Exposed to Radionuclides in the Environment

    Energy Technology Data Exchange (ETDEWEB)

    Blaylock, B.G.

    1993-01-01

    The purpose of this report is to present a methodology for evaluating the potential for aquatic biota to incur effects from exposure to chronic low-level radiation in the environment. Aquatic organisms inhabiting an environment contaminated with radioactivity receive external radiation from radionuclides in water, sediment, and from other biota such as vegetation. Aquatic organisms receive internal radiation from radionuclides ingested via food and water and, in some cases, from radionuclides absorbed through the skin and respiratory organs. Dose rate equations, which have been developed previously, are presented for estimating the radiation dose rate to representative aquatic organisms from alpha, beta, and gamma irradiation from external and internal sources. Tables containing parameter values for calculating radiation doses from selected alpha, beta, and gamma emitters are presented in the appendix to facilitate dose rate calculations. The risk of detrimental effects to aquatic biota from radiation exposure is evaluated by comparing the calculated radiation dose rate to biota to the U.S. Department of Energy's (DOE's) recommended dose rate limit of 0.4 mGy h{sup -1} (1 rad d{sup -1}). A dose rate no greater than 0.4 mGy h{sup -1} to the most sensitive organisms should ensure the protection of populations of aquatic organisms. DOE's recommended dose rate is based on a number of published reviews on the effects of radiation on aquatic organisms that are summarized in the National Council on Radiation Protection and Measurements Report No. 109 (NCRP 1991). The literature identifies the developing eggs and young of some species of teleost fish as the most radiosensitive organisms. DOE recommends that if the results of radiological models or dosimetric measurements indicate that a radiation dose rate of 0.1 mGy h{sup -1} will be exceeded, then a more detailed evaluation of the potential ecological consequences of radiation exposure to endemic

  3. [Radiation protection of the environment: anthropocentric and eco-centric principles].

    Science.gov (United States)

    Aleksakhin, R M; Fesenko, S V

    2004-01-01

    The second half of the XX century was dominated in the field of radiation protection of the environment by the anthropocentric concept stated by the International Commission on Radiological Protection (ICRP). According to this concept "if man is adequately protected by radiological standards then biota are also adequately protected". At the end of the XX--beginning of the XXI centuries in the area of area of radiation protection of nature an ecocentric strategy is beginning to develop where emphasis has swung to the protection of biota in their environment. Inadequacy of ICRP's anthroposentric concept is reported. Issues are discussed such as ecological dosimetry, nonequidosal irradiation of man and biota, criteria for estimating radiation induced changes in biota and man, as well as the need to harmonize permissible exposure doses to man and biota. An urgent need is stressed to develop a single (synthetic) concept of radiation protection which simultaneously ensures protection of human health and biota well-being in their environment. This concept is to be based on the recognition of the integrity of socio-natural ecosystems where man and biota are considered as a unity.

  4. Assessing the effects of ultraviolet radiation on the photosynthetic potential in Archean marine environments

    Science.gov (United States)

    Avila-Alonso, Dailé; Baetens, Jan M.; Cardenas, Rolando; de Baets, Bernard

    2017-07-01

    In this work, the photosynthesis model presented by Avila et al. in 2013 is extended and more scenarios inhabited by ancient cyanobacteria are investigated to quantify the effects of ultraviolet (UV) radiation on their photosynthetic potential in marine environments of the Archean eon. We consider ferrous ions as blockers of UV during the Early Archean, while the absorption spectrum of chlorophyll a is used to quantify the fraction of photosynthetically active radiation absorbed by photosynthetic organisms. UV could have induced photoinhibition at the water surface, thereby strongly affecting the species with low light use efficiency. A higher photosynthetic potential in early marine environments was shown than in the Late Archean as a consequence of the attenuation of UVC and UVB by iron ions, which probably played an important role in the protection of ancient free-floating bacteria from high-intensity UV radiation. Photosynthetic organisms in Archean coastal and ocean environments were probably abundant in the first 5 and 25 m of the water column, respectively. However, species with a relatively high efficiency in the use of light could have inhabited ocean waters up to a depth of 200 m and show a Deep Chlorophyll Maximum near 60 m depth. We show that the electromagnetic radiation from the Sun, both UV and visible light, could have determined the vertical distribution of Archean marine photosynthetic organisms.

  5. [Effect of the ISS Russian segment configuration on the service module radiation environment].

    Science.gov (United States)

    Mitrikas, V G

    2011-01-01

    Mathematical modeling of variations in the Service module radiation environment as a function of ISS Russian segment configuration was carried out using models of the RS modules and a spherical humanoid phantom. ISS reconfiguration impacted significantly only the phantom brought into the transfer compartment (ExT). The Radiation Safety Service prohibition for cosmonauts to stay in this compartment during solar flare events remains valid. In all other instances, error of dose estimation is higher as compared to dose value estimation with consideration for ISS RS reconfiguration.

  6. Micro Penning Trap for Continuous Magnetic Field Monitoring in High Radiation Environments

    Science.gov (United States)

    Latorre, Javiera; Bollen, Georg; Gulyuz, Kerim; Ringle, Ryan; Bado, Philippe; Dugan, Mark; Lebit Team; Translume Collaboration

    2016-09-01

    As new facilities for rare isotope beams, like FRIB at MSU, are constructed, there is a need for new instrumentation to monitor magnetic fields in beam magnets that can withstand the higher radiation level. Currently NMR probes, the instruments used extensively to monitor magnetic fields, do not have a long lifespans in radiation-high environments. Therefore, a radiation-hard replacement is needed. We propose to use Penning trap mass spectrometry techniques to make high precision magnetic field measurements. Our Penning microtrap will be radiation resistant as all of the vital electronics will be at a safe distance from the radiation. The trap itself is made from materials not subject to radiation damage. Penning trap mass spectrometers can determine the magnetic field by measuring the cyclotron frequency of an ion with a known mass and charge. This principle is used on the Low Energy Beam Ion Trap (LEBIT) minitrap at NSCL which is the foundation for the microtrap. We have partnered with Translume, who specialize in glass micro-fabrication, to develop a microtrap in fused-silica glass. A microtrap is finished and ready for testing at NSCL with all of the electronic and hardware components setup. DOE Phase II SBIR Award No. DE-SC0011313, NSF Award Number 1062410 REU in Physics, NSF under Grant No. PHY-1102511.

  7. Lunar radiation environment and space weathering from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER)

    Science.gov (United States)

    Schwadron, N. A.; Baker, T.; Blake, B.; Case, A. W.; Cooper, J. F.; Golightly, M.; Jordan, A.; Joyce, C.; Kasper, J.; Kozarev, K.; Mislinski, J.; Mazur, J.; Posner, A.; Rother, O.; Smith, S.; Spence, H. E.; Townsend, L. W.; Wilson, J.; Zeitlin, C.

    2012-03-01

    The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) measures linear energy transfer by Galactic Cosmic Rays (GCRs) and Solar Energetic Particles (SEPs) on the Lunar Reconnaissance Orbiter (LRO) Mission in a circular, polar lunar orbit. GCR fluxes remain at the highest levels ever observed during the space age. One of the largest SEP events observed by CRaTER during the LRO mission occurred on June 7, 2011. We compare model predictions by the Earth-Moon-Mars Radiation Environment Module (EMMREM) for both dose rates from GCRs and SEPs during this event with results from CRaTER. We find agreement between these models and the CRaTER dose rates, which together demonstrate the accuracy of EMMREM, and its suitability for a real-time space weather system. We utilize CRaTER to test forecasts made by the Relativistic Electron Alert System for Exploration (REleASE), which successfully predicts the June 7th event. At the maximum CRaTER-observed GCR dose rate (˜11.7 cGy/yr where Gy is a unit indicating energy deposition per unit mass, 1 Gy = 1 J/kg), GCRs deposit ˜88 eV/molecule in water over 4 billion years, causing significant change in molecular composition and physical structure (e.g., density, color, crystallinity) of water ice, loss of molecular hydrogen, and production of more complex molecules linking carbon and other elements in the irradiated ice. This shows that space weathering by GCRs may be extremely important for chemical evolution of ice on the Moon. Thus, we show comprehensive observations from the CRaTER instrument on the Lunar Reconnaissance Orbiter that characterizes the radiation environment and space weathering on the Moon.

  8. Experimental investigation of the radiation shielding efficiency of a MCP detector in the radiation environment near Jupiter's moon Europa

    Science.gov (United States)

    Tulej, M.; Meyer, S.; Lüthi, M.; Lasi, D.; Galli, A.; Piazza, D.; Desorgher, L.; Reggiani, D.; Hajdas, W.; Karlsson, S.; Kalla, L.; Wurz, P.

    2016-09-01

    Neutral Ion Mass spectrometer (NIM) is one of the instruments in the Particle Environmental Package (PEP) designed for the JUICE mission of ESA to the Jupiter system. NIM, equipped with a sensitive MCP ion detector, will conduct detailed measurements of the chemical composition of Jovian icy moons exospheres. To achieve high sensitivity of the instrument, radiation effects due to the high radiation background (high-energy electrons and protons) around Jupiter have to be minimised. We investigate the performance of an Al-Ta-Al composite stack as a potential shielding against high-energy electrons. Experiments were performed at the PiM1 beam line of the High Intensity Proton Accelerator Facilities located at the Paul Scherrer Institute, Villigen, Switzerland. The facility delivers a particle beam containing e-, μ- and π- with momentum from 17.5 to 345 MeV/c (Hajdas et al., 2014). The measurements of the radiation environment generated during the interaction of primary particles with the Al-Ta-Al material were conducted with dedicated beam diagnostic methods and with the NIM MCP detector. In parallel, modelling studies using GEANT4 and GRAS suites were performed to identify products of the interaction and predict ultimate fluxes and particle rates at the MCP detector. Combination of experiment and modelling studies yields detailed characterisation of the radiation fields produced by the interaction of the incident e- with the shielding material in the range of the beam momentum from 17.5 to 345 MeV/c. We derived the effective MCP detection efficiency to primary and secondary radiation and effective shielding transmission coefficients to incident high-energy electron beam in the range of applied beam momenta. This study shows that the applied shielding attenuates efficiently high-energy electrons. Nevertheless, owing to nearly linear increase of the bremsstrahlung production rate with incident beam energy, above 130 MeV their detection rates measured by the MCP

  9. CONSTRAINING THE RADIATION AND PLASMA ENVIRONMENT OF THE KEPLER CIRCUMBINARY HABITABLE-ZONE PLANETS

    Energy Technology Data Exchange (ETDEWEB)

    Zuluaga, Jorge I. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Mason, Paul A. [New Mexico State University—DACC, Las Cruces, NM 88003 (United States); Cuartas-Restrepo, Pablo A. [FACom—Instituto de Física—FCEN, Universidad de Antioquia, Calle 70 No. 52-21, Medellín (Colombia)

    2016-02-20

    The discovery of many planets using the Kepler telescope includes 10 planets orbiting eight binary stars. Three binaries, Kepler-16, Kepler-47, and Kepler-453, have at least one planet in the circumbinary habitable zone (BHZ). We constrain the level of high-energy radiation and the plasma environment in the BHZ of these systems. With this aim, BHZ limits in these Kepler binaries are calculated as a function of time, and the habitability lifetimes are estimated for hypothetical terrestrial planets and/or moons within the BHZ. With the time-dependent BHZ limits established, a self-consistent model is developed describing the evolution of stellar activity and radiation properties as proxies for stellar aggression toward planetary atmospheres. Modeling binary stellar rotation evolution, including the effect of tidal interaction between stars in binaries, is key to establishing the environment around these systems. We find that Kepler-16 and its binary analogs provide a plasma environment favorable for the survival of atmospheres of putative Mars-sized planets and exomoons. Tides have modified the rotation of the stars in Kepler-47, making its radiation environment less harsh in comparison to the solar system. This is a good example of the mechanism first proposed by Mason et al. Kepler-453 has an environment similar to that of the solar system with slightly better than Earth radiation conditions at the inner edge of the BHZ. These results can be reproduced and even reparameterized as stellar evolution and binary tidal models progress, using our online tool http://bhmcalc.net.

  10. Constraining the Radiation and Plasma Environment of the Kepler Circumbinary Habitable-zone Planets

    Science.gov (United States)

    Zuluaga, Jorge I.; Mason, Paul A.; Cuartas-Restrepo, Pablo A.

    2016-02-01

    The discovery of many planets using the Kepler telescope includes 10 planets orbiting eight binary stars. Three binaries, Kepler-16, Kepler-47, and Kepler-453, have at least one planet in the circumbinary habitable zone (BHZ). We constrain the level of high-energy radiation and the plasma environment in the BHZ of these systems. With this aim, BHZ limits in these Kepler binaries are calculated as a function of time, and the habitability lifetimes are estimated for hypothetical terrestrial planets and/or moons within the BHZ. With the time-dependent BHZ limits established, a self-consistent model is developed describing the evolution of stellar activity and radiation properties as proxies for stellar aggression toward planetary atmospheres. Modeling binary stellar rotation evolution, including the effect of tidal interaction between stars in binaries, is key to establishing the environment around these systems. We find that Kepler-16 and its binary analogs provide a plasma environment favorable for the survival of atmospheres of putative Mars-sized planets and exomoons. Tides have modified the rotation of the stars in Kepler-47, making its radiation environment less harsh in comparison to the solar system. This is a good example of the mechanism first proposed by Mason et al. Kepler-453 has an environment similar to that of the solar system with slightly better than Earth radiation conditions at the inner edge of the BHZ. These results can be reproduced and even reparameterized as stellar evolution and binary tidal models progress, using our online tool http://bhmcalc.net.

  11. Radiation environment of the LHCb Calorimeters in 2010-2013 (under review)

    CERN Document Server

    Corti, Gloria

    2017-01-01

    A set of passive and active radiation detectors has been installed around and in between the LHCb calorimeter subsystems to measure different aspects of the radiation environment. Cross calibrations between various types of measurements are performed and correlated with the evolving run conditions. Measurements are compared to FLUKA simulation estimates and an evaluation of the reliability of the simulation in different running scenarios is provided. The simulation is based on a detailed geometry of the LHCb experiment and reflects the conditions of Run1 with 7 and 8 TeV CM proton-proton collision energies. A carefully characterised simulation of radiation levels in the LHCb experiment is essential in providing input for technical choices in view of the planned upgrade of the experiment for operation at higher luminosity.

  12. Study on the mechanical property of polyimide film in space radiation environments

    Science.gov (United States)

    Shen, Zicai; Mu, Yongqiang; Ding, Yigang; Liu, Yuming; Zhao, Chunqing

    2016-01-01

    Polyimide films are widely used in spacecraft, but their mechanical properties would degrade in space environments, such as electron, proton, near ultraviolet or far ultraviolet, etc. The mechanical property and mechanism of polyimide film in electron, proton, near ultraviolet and far ultraviolet was studied by Φ800 combined space radiation test facility of Beijing Institute of Space Environment Engineering (BISSE. Rupture elongation of Kapton film decrease with the increase of the tensile deformation rate. The tensile strength and the rupture elongation of Kapton film decrease with the increase of electron and proton radiation, while tensile strength and the rupture elongation of Kapton film decrease firstly and then increase with near ultraviolet and far ultraviolet.

  13. Constraining the Radiation and Plasma Environment of the Kepler Circumbinary Habitable Zone Planets

    CERN Document Server

    Zuluaga, Jorge I; Cuartas, Pablo A

    2015-01-01

    The remarkable discovery of many planets and candidates using the Kepler telescope even includes ten planets orbiting eight binaries. Three out of the eight, Kepler 16, Kepler 47, and KIC 9632895, have at least one planet in the circumbinary habitable zone (BHZ). In previous work (Mason et al. 2013), we investigated the potential habitability of Earth-like circumbinary planets. In particular, we highlighted the role of mutual stellar tidal interaction and the resulting impact on terrestrial planet habitability. The Kepler binaries with planets in the BHZ are studied in order to constrain the high energy radiation and plasma environment of potentially habitable circumbinary planets. The limits of the BHZ in these binaries as a function of time are estimated and the habitability lifetime is calculated. A self-consistent model of the evolution of stellar rotation including the effect of tidal interaction is key to establishing the plasma and radiation environment. A comprehensive model of the evolution of stella...

  14. Implications for space radiation environment models from CREAM & CREDO measurements over half a solar cycle.

    Science.gov (United States)

    Dyer, C S; Truscott, P R; Peerless, C L; Watson, C J; Evans, H E; Knight, P; Cosby, M; Underwood, C; Cousins, T; Noulty, R; Maag, C

    1999-10-01

    Flight data obtained between 1990 and 1997 from the Cosmic Radiation Environment Monitors CREAM & CREDO carried on UoSAT-3, Space Shuttle, STRV-1a (Space Technology Research Vehicle) and APEX (Advanced Photovoltaic and Electronics Experiment Spacecraft) provide coverage over half a solar cycle. The modulation of cosmic rays and evolution of the South Atlantic Anomaly are observed, the former comprising a factor of three increase at high latitudes and the latter a general increase accompanied by a north-westward drift. Comparison of particle fluxes and linear energy transfer (LET) spectra is made with improved environment & radiation transport calculations which account for shield distributions and secondary particles. While there is an encouraging convergence between predictions and observations, significant improvements are still required, particularly in the treatment of locally produced secondary particles. Solar-particle events during this time period have LET spectra significantly below the October 1989 event which has been proposed as a worst case model.

  15. Measurements of the radiation environment from CREDO-II on STRV & APEX

    Science.gov (United States)

    Dyer, C. S.; Watson, C. J.; Peerless, C. L.; Sims, A. J.; Barth, J.

    1996-12-01

    The Cosmic Radiation Environment and Dosimetry experiments (CREDO) have now been operational in complementary orbits onboard the Advanced Photovoltaics & Electronics Experiment Spacecraft and Space Technology Research Vehicle since the summer of 1994 enabling extensive comparisons of measured dose and linear energy transfer (LET) spectra with the standard environment models. Measurements have been made at a range of shielding depths and detailed spacecraft models are employed. Significant discrepancies are seen for the outer-belt electron component which shows large time variations. Shielding effects are shown to be highly significant for both dose and LET spectra. Even allowing for this the measured LET spectra are somewhat below the predictions for solar minimum.

  16. The external gamma radiation environment from the Kiwi Phoebus, and Pewee reactors

    Science.gov (United States)

    Malenfant, R. E.

    1972-01-01

    During the past few years, ground tests of high-powered propulsion-prototype reactors have provided several opportunities to observe the external radiation environment. Reactor tests have been conducted in free air and inside of open well shields. Measurements were taken over distances ranging from contact with the pressure vessel out to greater than 5000' both during operation and after shutdown. Some measurements characteristic of each of the systems are presented and compared with results of calculations.

  17. High Performance Processors for Space Environments: A Subproject of the NASA Exploration Missions Systems Directorate "Radiation Hardened Electronics for Space Environments" Technology Development Program

    Science.gov (United States)

    Johnson, M.; Label, K.; McCabe, J.; Powell, W.; Bolotin, G.; Kolawa, E.; Ng, T.; Hyde, D.

    2007-01-01

    Implementation of challenging Exploration Systems Missions Directorate objectives and strategies can be constrained by onboard computing capabilities and power efficiencies. The Radiation Hardened Electronics for Space Environments (RHESE) High Performance Processors for Space Environments project will address this challenge by significantly advancing the sustained throughput and processing efficiency of high-per$ormance radiation-hardened processors, targeting delivery of products by the end of FY12.

  18. Qualification of electronic components and systems in a LHC Tunnel Radiation Environment

    CERN Document Server

    Rausch, R; Wijnands, Thijs

    2002-01-01

    Around 10.200 electronic crates will be installed in the LHC underground areas of which some 4.200 will be connected to the machine control network. Some of the electronic equipment will be housed under the cryostats of the main dipoles inside the tunnel. Other equipment will be placed alongside the tunnel, in the alcoves or in galleries parallel to the machine. In the regular arcs and in the dispersion suppressors areas the expected annual dose is low, i.e. only a few Gy/y. However, preliminary radiation tests showed that electronic equipment fails even at such low dose rates. Since radiation qualification of all tunnel electronics is essential in order to guarantee its reliable operation over the lifetime of the machine, a LHC radiation test facility was commissioned in the North Experimental Area of the SPS accelerator. This paper presents the simulation study concerning the radiation environment of the LHC Radiation Test Facility and gives an overview of the various underground electronic systems as they ...

  19. Degradation of thermal control materials under a simulated radiative space environment

    Science.gov (United States)

    Sharma, A. K.; Sridhara, N.

    2012-11-01

    A spacecraft with a passive thermal control system utilizes various thermal control materials to maintain temperatures within safe operating limits. Materials used for spacecraft applications are exposed to harsh space environments such as ultraviolet (UV) and particle (electron, proton) irradiation and atomic oxygen (AO), undergo physical damage and thermal degradation, which must be considered for spacecraft thermal design optimization and cost effectiveness. This paper describes the effect of synergistic radiation on some of the important thermal control materials to verify the assumptions of beginning-of-life (BOL) and end-of-life (EOL) properties. Studies on the degradation in the optical properties (solar absorptance and infrared emittance) of some important thermal control materials exposed to simulated radiative geostationary space environment are discussed. The current studies are purely related to the influence of radiation on the degradation of the materials; other environmental aspects (e.g., thermal cycling) are not discussed. The thermal control materials investigated herein include different kind of second-surface mirrors, white anodizing, white paints, black paints, multilayer insulation materials, varnish coated aluminized polyimide, germanium coated polyimide, polyether ether ketone (PEEK) and poly tetra fluoro ethylene (PTFE). For this purpose, a test in the constant vacuum was performed reproducing a three year radiative space environment exposure, including ultraviolet and charged particle effects on North/South panels of a geostationary three-axis stabilized spacecraft. Reflectance spectra were measured in situ in the solar range (250-2500 nm) and the corresponding solar absorptance values were calculated. The test methodology and the degradations of the materials are discussed. The most important degradations among the low solar absorptance materials were found in the white paints whereas the rigid optical solar reflectors remained quite

  20. Use of COTS [commercial-off-the-shelf] Microelectronics in Radiation Environments

    Energy Technology Data Exchange (ETDEWEB)

    Winokur, P.S.; Lum, G.K.; Shaneyfelt, M.R.; Sexton, F.W.; Hash, G.L.; Scott, L.

    1999-07-07

    This paper addresses key issues for the cost-effective use of COTS microelectronics in radiation environments that enable circuit or system designers to manage risks and ensure mission success. COTS parts with low radiation tolerance should not be used when they degrade mission critical functions or lead to premature system failure. We review several factors and tradeoffs affecting the successful application of COTS parts including (1) hardness assurance and qualification issues, (2) system hardening techniques, and (3) life-cycle costs. The paper also describes several experimental studies that address trends in total-dose, transient, and single-event radiation hardness as COTS technology scales to smaller feature sizes. As an example, the level at which dose-rate upset occurs in Samsung SRAMS increases from 1.4x10{sup 8} rads(Si)/s for a 256K SRAM to 7.7x10{sup 9} rads(Si)/s for a 4M SRAM, indicating unintentional hardening improvements in the design or process of a commercial technology. Additional experiments were performed to quantify variations in radiation hardness for COTS parts. In one study, only small (10-15%) variations were found in the dose-rate upset and latchup thresholds for Samsung 4M SRAMS from three different date codes. In another study, irradiations of 4M SRAMS from Samsung, Hitachi, and Toshiba indicate large differences in total-dose radiation hardness. The paper attempts to carefully define terms and clear up misunderstandings about the definitions of ''COTS'' and ''radiation-hardened'' technology.

  1. Fiber Bragg gratings in the radiation environment: Change under the influence of radiolytic hydrogen

    Science.gov (United States)

    Butov, Oleg V.; Golant, Konstantin M.; Shevtsov, Igor'A.; Fedorov, Artem N.

    2015-08-01

    The change of the transmission spectra of fiber Bragg gratings written in the optical fibers, whose silica cores are doped with either germanium or nitrogen, is studied experimentally under the influence of gamma-radiation. The transmission spectra in the neighborhood of the resonance (Bragg) wavelengths were regularly recorded "in-situ" in the course of irradiation during 24 days. For this purpose, uncoated gratings were placed in a pool near the spent fuel rods of a nuclear reactor. The fibers with the gratings written in them were in immediate contact with water. The estimated total absorbed radiation dose of the fibers is approximately 5 MGy. Molecular hydrogen, which is produced by radiolysis of water and penetrates into the core of silica fiber, is found to interact with the defects of Ge-doped silica induced by gamma-radiation, thereby causing a strong impact on the parameters of the spectrum of the Bragg gratings. On the contrary, in the case of gratings inscribed in N-doped silica fibers, the hydrogen molecules interact with defects induced in the course of laser UV exposure during the grating writing only. The possible subsequent formation of additional defects in N-doped silica under the influence of gamma-radiation has no substantial impact on the transmission spectra of Bragg gratings, which remained stable. The obtained results suggest that a small amount of molecular hydrogen resided in the fiber core is the main source of radiation instability of Ge-doped fiber Bragg grating sensors in radiation environments. These hydrogen molecules can remain in the Bragg gratings, in particular, after the inscription process in the hydrogen-loaded fibers.

  2. Fiber Bragg gratings in the radiation environment: Change under the influence of radiolytic hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Butov, Oleg V., E-mail: obutov@mail.ru; Golant, Konstantin M. [Kotel' nikov Institute of Radio-Engineering and Electronics of RAS, 11-7 Mokhovaya Str., Moscow 125009 (Russian Federation); Shevtsov, Igor' A.; Fedorov, Artem N. [Prolog LLC, PO Box 3007, Obninsk, the Kaluga Region 249033 (Russian Federation)

    2015-08-21

    The change of the transmission spectra of fiber Bragg gratings written in the optical fibers, whose silica cores are doped with either germanium or nitrogen, is studied experimentally under the influence of gamma-radiation. The transmission spectra in the neighborhood of the resonance (Bragg) wavelengths were regularly recorded “in-situ” in the course of irradiation during 24 days. For this purpose, uncoated gratings were placed in a pool near the spent fuel rods of a nuclear reactor. The fibers with the gratings written in them were in immediate contact with water. The estimated total absorbed radiation dose of the fibers is approximately 5 MGy. Molecular hydrogen, which is produced by radiolysis of water and penetrates into the core of silica fiber, is found to interact with the defects of Ge-doped silica induced by gamma-radiation, thereby causing a strong impact on the parameters of the spectrum of the Bragg gratings. On the contrary, in the case of gratings inscribed in N-doped silica fibers, the hydrogen molecules interact with defects induced in the course of laser UV exposure during the grating writing only. The possible subsequent formation of additional defects in N-doped silica under the influence of gamma-radiation has no substantial impact on the transmission spectra of Bragg gratings, which remained stable. The obtained results suggest that a small amount of molecular hydrogen resided in the fiber core is the main source of radiation instability of Ge-doped fiber Bragg grating sensors in radiation environments. These hydrogen molecules can remain in the Bragg gratings, in particular, after the inscription process in the hydrogen-loaded fibers.

  3. Space Radiation Environment Prediction for VLSI microelectronics devices onboard a LEO Satellite using OMERE-Trad Software

    Science.gov (United States)

    Sajid, Muhammad

    This tutorial/survey paper presents the assessment/determination of level of hazard/threat to emerging microelectronics devices in Low Earth Orbit (LEO) space radiation environment with perigee at 300 Km, apogee at 600Km altitude having different orbital inclinations to predict the reliability of onboard Bulk Built-In Current Sensor (BBICS) fabricated in 350nm technology node at OptMA Lab. UFMG Brazil. In this context, the various parameters for space radiation environment have been analyzed to characterize the ionizing radiation environment effects on proposed BBICS. The Space radiation environment has been modeled in the form of particles trapped in Van-Allen radiation belts(RBs), Energetic Solar Particles Events (ESPE) and Galactic Cosmic Rays (GCR) where as its potential effects on Device- Under-Test (DUT) has been predicted in terms of Total Ionizing Dose (TID), Single-Event Effects (SEE) and Displacement Damage Dose (DDD). Finally, the required mitigation techniques including necessary shielding requirements to avoid undesirable effects of radiation environment at device level has been estimated /determined with assumed standard thickness of Aluminum shielding. In order to evaluate space radiation environment and analyze energetic particles effects on BBICS, OMERE toolkit developed by TRAD was utilized.

  4. The Martian and extraterrestrial UV radiation environment. Part II: further considerations on materials and design criteria for artificial ecosystems.

    Science.gov (United States)

    Cockell, C S

    2001-12-01

    Ultraviolet radiation is an important natural physical influence on organism function and ecosystem interactions. The UV radiation fluxes in extraterrestrial environments are substantially different from those experienced on Earth. On Mars, the moon and in Earth orbit they are more biologically detrimental than on Earth. Based on previously presented fluxes and biologically weighted irradiances, this paper considers in more detail measures to mitigate UV radiation damage and methods to modify extraterrestrial UV radiation environments in artificial ecosystems that use natural sunlight. The transmission characteristics of a Martian material that will mimic the terrestrial UV radiation environment are presented. Transmissivity characteristics of other Martian and lunar materials are described. Manufacturing processes for the production of plastics and glass on the lunar and Martian surface are presented with special emphasis on photobiological requirements. Novel UV absorbing configurations are suggested.

  5. The Chandra X-Ray Observatory's Radiation Environment and the AP-8/AE-8 Model

    CERN Document Server

    Virani, S N; Plucinsky, P P; Butt, Y M; Virani, Shanil N.; Mueller-Mellin, Reinhold; Plucinsky, Paul P.; Butt, Yousaf M.

    2000-01-01

    The Chandra X-ray Observatory (CXO) was launched on July 23, 1999 and reached its final orbit on August 7, 1999. The CXO is in a highly elliptical orbit, approximately 140,000 km x 10,000 km, and has a period of approximately 63.5 hours (~ 2.65 days). It transits the Earth's Van Allen belts once per orbit during which no science observations can be performed due to the high radiation environment. The Chandra X-ray Observatory Center (CXC) currently uses the National Space Science Data Center's ``near Earth'' AP-8/AE-8 radiation belt model to predict the start and end times of passage through the radiation belts. However, our scheduling software uses only a simple dipole model of the Earth's magnetic field. The resulting B, L magnetic coordinates, do not always give sufficiently accurate predictions of the start and end times of transit of the Van Allen belts. We show this by comparing to the data from Chandra's on-board radiation monitor, the EPHIN (Electron, Proton, Helium Instrument particle detector) instr...

  6. High temperature radiator materials for applications in the low Earth orbital environment

    Science.gov (United States)

    Rutledge, Sharon K.; Banks, Bruce A.; Mirtich, Michael J.; Lebed, Richard; Brady, Joyce; Hotes, Deborah; Kussmaul, Michael

    1987-01-01

    Radiators must be constructed of materials which have high emittance in order to efficiently radiate heat from high temperature space power systems. In addition, if these radiators are to be used for applications in the low Earth orbital environment, they must not be detrimentally affected by exposure to atomic oxygen. Four materials selected as candidate radiator materials (304 stainless steel, copper, titanium-6% aluminum-4% vanadium (Ti-6%Al-4%V), and niobium-1% zirconium (Nb-1%Zr)) were surface modified by acid etching, heat treating, abrading, sputter texturing, electrochemical etching, and combinations of the above in order to improve their emittance. Combination treatment techniques with heat treating as the second treatment provided about a factor of two improvement in emittance for 304 stainless steel, Ti-6%Al-4%V, and Nb-1%Zr. A factor of three improvement in emittance occurred for discharge chamber sputter textured copper. Exposure to atomic oxygen in an RF plasma asher did not significantly change the emittance of those samples that had been heat treated as part of their texturing process. An evaluation of oxygen penetration is needed to understand how oxidation affects the mechanical properties of these materials when heat treated.

  7. Real-time fibre optic radiation dosimeters for nuclear environment monitoring around thermonuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A. Fernandez; Brichard, B. [SCK .CEN, Belgian Nuclear Research Centre, Boeretang 200, B-2400 Mol (Belgium); O' Keeffe, S.; Fitzpatrick, C.; Lewis, E. [Electronic and Computer Engineering Department, University of Limerick, Limerick (Ireland); Vaille, J.-R.; Dusseau, L. [CEM2-Universite Montpellier II, cc083 place E. Bataillon, 34095 Montpellier Cedex 05 (France); Jackson, D.A. [School of Physical Sciences, University of Kent, Kent CT2 7NR (United Kingdom); Ravotti, F.; Glaser, M. [European Organization for Nuclear Research CERN, TS-LEA-RAD/PH-DT2-SD, CH-1211 Geneva 23 (Switzerland); El-Rabii, H. [Laboratoire de Combustion et de Detonique, ENSMA/CNRS, 1 av. Clement Ader, 86961 Chasseneuil-Futuroscope (France)], E-mail: afernand@sckcen.be

    2008-01-15

    The ability of fibre optic sensors to operate in hazardous nuclear environments and their intrinsic immunity to electro-magnetic interference make fibre optic sensing a very promising technology for the future ITER thermonuclear fusion reactor. In this paper, we evaluate fibre optic sensing technology for monitoring radiation dose in the vicinity of ITER during its operation and during the maintenance periods. First, the performance of an OSL dosimeter interrogated remotely using radiation tolerant optical fibres is evaluated both for real-time and integrating measurements for doses exceeding 100 Gy. We demonstrate its satisfactory operation in a mixed gamma neutron field. Second, we discuss the successful calibration of a new scintillating fibre optic radiation probe based on CsI(TI) crystals for operation in the dose-rate range 0.3-3000 mGy/h. The CsI(TI) crystal scintillator is mounted at the end of a 10-m long multimode fibre transceiver link to allow for remote deployment. The probes can detect and measure gamma dose rates ranging from 1 to 1000 mGy/h. Finally, we investigate the possible use of commercially available PMMA plastic optical fibres as on-line dosimeters up to 34 kGy. The dose measurement is derived from the radiation-induced attenuation in the optical fibre itself. A novel interrogation scheme based on a ratiometric technique is proposed for real-time dosimetry.

  8. Crustaceous lichens sensitive monitor of caesium-137 radiation level in terrestrial environment

    Institute of Scientific and Technical Information of China (English)

    Du Chunguang; Zhao Ye; Zhang Jing; Xu Cuihua

    2005-01-01

    The activity of caesium-137 (Bq/kg) in the crustaceous lichens and other samples was determined to prove the feasibility that crustaceous lichens work as a sensitive biology monitor to record the caesium-137 (Bq/kg) radiation levels of terrestrial environment. The measurements were performed with GEM series HPGe (high-purity Germanium) coaxial detector system (ADCAM -100) made by EC & GORTEC Company in USA. It was found that the activity of caesium-137 (Bq/kg) in the crustaceous lichens was one order of magnitude higher than that found in surface soil,and was over three orders of magnitude higher than those found in the familiar biological samples. These results proved that crustaceous lichens may be one of the most sensitive biological monitors about the remote transmission and environmental radiation levels of caesium-137.

  9. Computer modeling characterization, and applications of Gallium Arsenide Gunn diodes in radiation environments

    Energy Technology Data Exchange (ETDEWEB)

    El- Basit, Wafaa Abd; El-Ghanam, Safaa Mohamed; Kamh, Sanaa Abd El-Tawab [Electronics Research Laboratory, Physics Department, Faculty of Women for Arts, Science and Education, Ain-Shams University, Cairo (Egypt); Abdel-Maksood, Ashraf Mosleh; Soliman, Fouad Abd El-Moniem Saad [Nuclear Materials Authority, Cairo (Egypt)

    2016-10-15

    The present paper reports on a trial to shed further light on the characterization, applications, and operation of radar speed guns or Gunn diodes on different radiation environments of neutron or γ fields. To this end, theoretical and experimental investigations of microwave oscillating system for outer-space applications were carried out. Radiation effects on the transient parameters and electrical properties of the proposed devices have been studied in detail with the application of computer programming. Also, the oscillation parameters, power characteristics, and bias current were plotted under the influence of different γ and neutron irradiation levels. Finally, shelf or oven annealing processes were shown to be satisfactory techniques to recover the initial characteristics of the irradiated devices.

  10. Moon's Radiation Environment and Expected Performance of Solar Cells during Future Lunar Missions

    CERN Document Server

    Girish, T E

    2010-01-01

    Several lunar missions are planned ahead and there is an increasing demand for efficient photovoltaic power generation in the moon. The knowledge of solar cell operation in the lunar surface obtained during early seventies need to be updated considering current views on solar variability and emerging space solar cell technologies. In this paper some aspects of the solar cell performance expected under variable lunar radiation environment during future space missions to moon are addressed. We have calculated relative power expected from different types of solar cells under extreme solar proton irradiation conditions and high lunar daytime temperature. It is also estimated that 2-3 % of annual solar cell degradation is most probable during the future lunar missions. We have also discussed photovoltaic power generation in long term lunar bases emphasizing technological needs such as sunlight concentration, solar cell cooling and magnetic shielding of radiation for improving the efficiency of solar cells in the l...

  11. Computer Modeling, Characterization, and Applications of Gallium Arsenide Gunn Diodes in Radiation Environments

    Directory of Open Access Journals (Sweden)

    Wafaa Abd El-Basit

    2016-10-01

    Full Text Available The present paper reports on a trial to shed further light on the characterization, applications, and operation of radar speed guns or Gunn diodes on different radiation environments of neutron or γ fields. To this end, theoretical and experimental investigations of microwave oscillating system for outer-space applications were carried out. Radiation effects on the transient parameters and electrical properties of the proposed devices have been studied in detail with the application of computer programming. Also, the oscillation parameters, power characteristics, and bias current were plotted under the influence of different γ and neutron irradiation levels. Finally, shelf or oven annealing processes were shown to be satisfactory techniques to recover the initial characteristics of the irradiated devices.

  12. Real-time 3D radiation risk assessment supporting simulation of work in nuclear environments.

    Science.gov (United States)

    Szőke, I; Louka, M N; Bryntesen, T R; Bratteli, J; Edvardsen, S T; RøEitrheim, K K; Bodor, K

    2014-06-01

    This paper describes the latest developments at the Institute for Energy Technology (IFE) in Norway, in the field of real-time 3D (three-dimensional) radiation risk assessment for the support of work simulation in nuclear environments. 3D computer simulation can greatly facilitate efficient work planning, briefing, and training of workers. It can also support communication within and between work teams, and with advisors, regulators, the media and public, at all the stages of a nuclear installation's lifecycle. Furthermore, it is also a beneficial tool for reviewing current work practices in order to identify possible gaps in procedures, as well as to support the updating of international recommendations, dissemination of experience, and education of the current and future generation of workers.IFE has been involved in research and development into the application of 3D computer simulation and virtual reality (VR) technology to support work in radiological environments in the nuclear sector since the mid 1990s. During this process, two significant software tools have been developed, the VRdose system and the Halden Planner, and a number of publications have been produced to contribute to improving the safety culture in the nuclear industry.This paper describes the radiation risk assessment techniques applied in earlier versions of the VRdose system and the Halden Planner, for visualising radiation fields and calculating dose, and presents new developments towards implementing a flexible and up-to-date dosimetric package in these 3D software tools, based on new developments in the field of radiation protection. The latest versions of these 3D tools are capable of more accurate risk estimation, permit more flexibility via a range of user choices, and are applicable to a wider range of irradiation situations than their predecessors.

  13. Space weather circulation model of plasma clouds as background radiation medium of space environment.

    Science.gov (United States)

    Kalu, A. E.

    A model for Space Weather (SW) Circulation with Plasma Clouds as background radiation medium of Space Environment has been proposed and discussed. Major characteristics of the model are outlined and the model assumes a baroclinic Space Environment in view of observed pronounced horizontal electron temperature gradient with prevailing weak vertical temperature gradient. The primary objective of the study is to be able to monitor and realistically predict on real- or near real-time SW and Space Storms (SWS) affecting human economic systems on Earth as well as the safety and Physiologic comfort of human payload in Space Environment in relation to planned increase in human space flights especially with reference to the ISS Space Shuttle Taxi (ISST) Programme and other prolonged deep Space Missions. Although considerable discussions are now available in the literature on SW issues, routine Meteorological operational applications of SW forecast data and information for Space Environment are still yet to receive adequate attention. The paper attempts to fill this gap in the literature of SW. The paper examines the sensitivity and variability in 3-D continuum of Plasmas in response to solar radiation inputs into the magnetosphere under disturbed Sun condition. Specifically, the presence of plasma clouds in the form of Coronal Mass Ejections (CMEs) is stressed as a major source of danger to Space crews, spacecraft instrumentation and architecture charging problems as well as impacts on numerous radiation - sensitive human economic systems on Earth. Finally, the paper considers the application of model results in the form of effective monitoring of each of the two major phases of manned Spaceflights - take-off and re-entry phases where all-time assessment of spacecraft transient ambient micro-incabin and outside Space Environment is vital for all manned Spaceflights as recently evidenced by the loss of vital information during take-off of the February 1, 2003 US Columbia

  14. A Preliminary Study on the Radiation dose Distribution in the Pyroprocess Hot Cell Environment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chankyu; Kim, Myung Soo; Kim, Giyoon; Lee, Eunjoong; Lee, Jeong Tae; Cho, Gyuseong [KAIST, Daejeon (Korea, Republic of); Ahn, Seongkyu; Park, Sehwan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    Pyroprocessing is the promising technology for treatment of spent fuels. Because it is based on the collective recovery of TRU, it has an advantage in proliferation resistance compared to conventional aqueous processes. Development of pyroprocessing has positive effects to the public through reduction of the high-level radioactive waste and the effective use of energy resources. In Korea, Korea Atomic Energy Research Institute (KAERI) has researched pyroprocessing since 1997. The engineering scale integrated inactive pyroprocess facility (PRIDE) was constructed and test operation has been performed. A study on the preliminary conceptual design and cost estimation for a larger-scale model facility is in progress. The safeguards are essential in the pyroprocessing facility for proliferation resistance. To establish the reliable safeguards, the preliminary studies on radiation resistance requirements, assessment of the safeguards system applicability, and shielding of the safeguards equipment are required. Therefore, first of all, the radiation flux and dose distribution in hot cell environment have to be studied. The previous studies focused on the neutron flux at the pyroprocessing however they are limited to the individual unit process. In this study, the flux and dose distribution of neutron and gamma-ray in the hot cell environment of the pilot pyroprocessing facility are investigated. Based on the simplified material flow of pyroprocess, the material distribution model is established. In this study, the radiation flux and dose distribution in the hot cell environment of the pilot-scale pyroprocessing facility model is investigated preliminarily by the MCNP6 simulation. Based on the established material flow model, the material composition at each stage is calculated and used for the simulation. The simple hot cell structure and process batch size were assumed based on the previous studies.

  15. Multijunction Solar Cell Efficiencies: Effect of Spectral Window, Optical Environment and Radiative Coupling

    Science.gov (United States)

    2014-09-04

    the photon  ux as a function of energy in the 1 sun AM1.5D spectrum, q is the charge of an electron, h is Planck’s constant, c is the speed of light, k...reduced photon  ux will decrease both photocurrent and voltage. This decline is still the most severe for B ¼ 0 because there is no radiative coupling to...optical environment dictate the performance of subcells in a multi- junction cell. As the number of subcells increases, the photon  ux each subcell

  16. Effect of ionizing radiation on the waste package environment; Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Reed, D.T. [Argonne National Lab., IL (USA); Van Konynenburg, R.A. [Lawrence Livermore National Lab., CA (USA)

    1991-05-01

    The radiolytic production of nitrogen oxides, nitrogen acids and ammonia are discussed in relation to the expected environment in a high-level waste repository that may be constructed at the Yucca Mountain site if it is found to be suitable. Both literature data and repository-relevant data are summarized for air-water vapor systems. The limiting cases of a dry air and a pure water vapor gas phase are also discussed. Design guidelines and recommendations, based solely on the potential consequence of radiation enhancement of corrosion, are given. 13 refs., 5 figs., 1 tab.

  17. Radon measurements by etched track detectors applications in radiation protection, earth sciences and the environment

    CERN Document Server

    Durrani, Saeed A

    1997-01-01

    Exposure to radon gas, which is present in the environment naturally, constitutes over half the radiation dose received by the general public annually. At present, the most widely used method of measuring radon concentration levels throughout the world, both in dwellings and in the field, is by etched track detectors - also known as Solid State Nuclear Detectors (SSNTDs). Although this is not only the most widely used method but is also the simplest and the cheapest, yet there is at present no book available on the market globally, devoted exclusively or largely to the methodology of, and deal

  18. Accuracy of Analog Fiber-Optic Links in Pulsed Radiation Environments

    Energy Technology Data Exchange (ETDEWEB)

    E. K. Miller, G. S. Macrum, I. J. McKenna, et al.

    2007-12-01

    Interferometric fiber-optic links used in pulsed-power experiments are evaluated for accuracy in the presence of radiation fields which alter fiber transmission. Amplitude-modulated format (e.g., Mach-Zehnder) and phase-modulated formats are compared. Historically, studies of radiation effects on optical fibers have focused on degradation and recovery of the fibers transmission properties; such work is either in the context of survivability of fibers in catastrophic conditions or suitability of fibers installed for command and control systems within an experimental facility [1], [2]. In this work, we consider links used to transmit realtime diagnostic data, and we analyze the error introduced by radiation effects during the drive pulse. The result is increased uncertainties in key parameters required to unfold the sinusoidal transfer function. Two types of modulation are considered: amplitude modulation typical of a Mach-Zehnder (M-Z) modulator [3], and phase modulation, which offers more flexible demodulation options but relies on the spatiotemporal coherence of the light in the fiber. The M-Z link is shown schematically in Fig. 1, and the phase-modulated link is shown in Fig. 2. We present data from two experimental environments: one with intense, controlled radiation fields to simulate conditions expected at the next generation of pulsed-power facilities, and the second with radiation effects below the noise level of the recording system. In the first case, we intentionally expose three types of single-mode fiber (SMF) to ionizing radiation and study the response by simultaneously monitoring phase and amplitude of the transmitted light. The phase and amplitude effects are evidently dominated by different physical phenomena, as their recovery dynamics are markedly different; both effects, though, show similar short-term behavior during exposure, integrating the dose at the dose levels studied, from 1 to 300 kRad, over the exposure times of 50 ps and 30 ns. In the

  19. Micronuclei as biomarkers of genotoxicity of gamma radiation in aquatic environments

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Luanna R.S.; Silva, Edvane B.; Melo, Ana M.M.A. [Universidade Federal de Pernambuco (GERAR/DEN/UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia; Silva, Ronaldo C. da [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Genetica; Amancio, Francisco F. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Biofisica e Radiobiologia. Lab. de Radiobiologia

    2011-07-01

    Ionizing radiation is a genotoxic agent, inducing gene mutations and cellular death. Several efforts have been defendants in the development of techniques for measurement of radiation damage in biological systems. Among these techniques, micronuclei test has been showing as a great bio marker of DNA damage, being used in environmental monitoring to detect genotoxic agents in the environment. Additionally, organisms as Biomphalaria glabrata, freshwater molluscs, presents itself as an excellent model to assess damage caused by physical and chemical agents, due their biological and environmental characteristics. The snails were divided into groups of 5 individuals exposed to doses of 0 (control), 25, 35, 45 and 55 Gy of {sup 60}Co. After 48 hours of irradiation, the hemo lymph was collected and prepared the slides, which were stained with Giemsa and analyzed the cellular changes in haemocytes Statistical analysis was accomplished through chi-square test, ANOVA and Tukey test (p< 0,05). The results indicated that B. glabrata showed to be sensitive to gamma radiation. The snails irradiated with 35 Gy showed a decrease of haemocytes, while that of 55 Gy increased. Cellular and morphological changes were observed at doses of 35, 45 and 55 Gy and the dose of 55 Gy, the most radiotoxic. (author)

  20. Ethics, genetics and dynamics: an emerging systematic approach to radiation protection of the environment.

    Science.gov (United States)

    Pentreath, R J

    2004-01-01

    There is now a general consensus of opinion that an explicit approach is necessary to demonstrate radiation protection of the environment, and that this approach needs to be developed in a systematic way. The framework that is emerging links ethical and moral issues (anthropocentric, biocentric, and ecocentric) to broad-based principles and objectives of environmental protection (sustainable development, maintaining biological diversity, and habitat protection) and then links these, in turn, to the needs of current environmental management practices, such as environmental exploitation, pollution control, and nature conservation. The relevance of this to radiation is that its effects (such as causing early mortality, morbidity, reduced reproductive success, as well as resulting in observable (scorable) cytogenetic damage) are those that may have a bearing on these same environmental management practices. The devise that would appear to be most useful to bridge the gap between our disparate data on radiation effects and the needs of environmental management, is that of adding to the concept of Reference Man in the shape of a small set of Reference Animals and Plants. This approach has now been adopted by the ICRP, adding new dynamics-the motive forces, both moral and physical-to the subject. The way is now clear for rapid progress to be made on a number of fronts.

  1. Ethics, genetics and dynamics: an emerging systematic approach to radiation protection of the environment

    Energy Technology Data Exchange (ETDEWEB)

    Pentreath, R.J

    2004-07-01

    There is now a general consensus of opinion that an explicit approach is necessary to demonstrate radiation protection of the environment, and that this approach needs to be developed in a systematic way. The framework that is emerging links ethical and moral issues (anthropocentric, biocentric, and ecocentric) to broad-based principles and objectives of environmental protection (sustainable development, maintaining biological diversity, and habitat protection) and then links these, in turn, to the needs of current environmental management practices, such as environmental exploitation, pollution control, and nature conservation. The relevance of this to radiation is that its effects (such as causing early mortality, morbidity, reduced reproductive success, as well as resulting in observable (scorable) cytogenetic damage) are those that may have a bearing on these same environmental management practices. The devise that would appear to be most useful to bridge the gap between our disparate data on radiation effects and the needs of environmental management, is that of adding to the concept of Reference Man in the shape of a small set of Reference Animals and Plants. This approach has now been adopted by the ICRP, adding new dynamics--the motive forces, both moral and physical--to the subject. The way is now clear for rapid progress to be made on a number of fronts.

  2. Transfer of Real-time Dynamic Radiation Environment Assimilation Model; Research to Operation

    Science.gov (United States)

    Cho, K. S. F.; Hwang, J.; Shin, D. K.; Kim, G. J.; Morley, S.; Henderson, M. G.; Friedel, R. H.; Reeves, G. D.

    2015-12-01

    Real-time Dynamic Radiation Environment Assimilation Model (rtDREAM) was developed by LANL for nowcast of energetic electrons' flux at the radiation belt to quantify potential risks from radiation damage at the satellites. Assimilated data are from multiple sources including LANL assets (GEO, GPS). For transfer from research to operation of the rtDREAM code, LANL/KSWC/NOAA makes a Memorandum Of Understanding (MOU) on the collaboration between three parts. By this MOU, KWSC/RRA provides all the support for transitioning the research version of DREAM to operations. KASI is primarily responsible for providing all the interfaces between the current scientific output formats of the code and useful space weather products that can be used and accessed through the web. In the second phase, KASI will be responsible in performing the work needed to transform the Van Allen Probes beacon data into "DREAM ready" inputs. KASI will also provide the "operational" code framework and additional data preparation, model output, display and web page codes back to LANL and SWPC. KASI is already a NASA partnering ground station for the Van Allen Probes' space weather beacon data and can here show use and utility of these data for comparison between rtDREAM and observations by web. NOAA has offered to take on some of the data processing tasks specific to the GOES data.

  3. Markedly enhanced absorption and direct radiative forcing of black carbon under polluted urban environments

    Science.gov (United States)

    Peng, Jianfei; Hu, Min; Guo, Song; Du, Zhuofei; Zheng, Jing; Shang, Dongjie; Levy Zamora, Misti; Zeng, Limin; Shao, Min; Wu, Yu-Sheng; Zheng, Jun; Wang, Yuan; Glen, Crystal R.; Collins, Donald R.; Molina, Mario J.

    2016-04-01

    Black carbon (BC) exerts profound impacts on air quality and climate because of its high absorption cross-section over a broad range of electromagnetic spectra, but the current results on absorption enhancement of BC particles during atmospheric aging remain conflicting. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China, and Houston, United States, using a novel environmental chamber approach. BC aging exhibits two distinct stages, i.e., initial transformation from a fractal to spherical morphology with little absorption variation and subsequent growth of fully compact particles with a large absorption enhancement. The timescales to achieve complete morphology modification and an absorption amplification factor of 2.4 for BC particles are estimated to be 2.3 h and 4.6 h, respectively, in Beijing, compared with 9 h and 18 h, respectively, in Houston. Our findings indicate that BC under polluted urban environments could play an essential role in pollution development and contribute importantly to large positive radiative forcing. The variation in direct radiative forcing is dependent on the rate and timescale of BC aging, with a clear distinction between urban cities in developed and developing countries, i.e., a higher climatic impact in more polluted environments. We suggest that mediation in BC emissions achieves a cobenefit in simultaneously controlling air pollution and protecting climate, especially for developing countries.

  4. Radioactivity in food and the environment: calculations of UK radiation doses using integrated assessment methods

    Energy Technology Data Exchange (ETDEWEB)

    Camplin, W C; Brownless, G P; Round, G D; Winpenny, K; Hunt, G J [Centre for Environment, Fisheries and Aquaculture Science, CEFAS Laboratory, Lowestoft (United Kingdom)

    2002-12-01

    A new method for estimating radiation doses to UK critical groups is proposed for discussion. Amongst others, the Food Standards Agency (FSA) and the Scottish Environment Protection Agency (SEPA) undertake surveillance of UK food and the environment as a check on the effect of discharges of radioactive wastes. Discharges in gaseous and liquid form are made under authorisation by the Environment Agency and SEPA under powers in the Radioactive Substance Act. Results of surveillance by the FSA and SEPA are published in the Radioactivity in Food and the Environment (RIFE) report series. In these reports, doses to critical groups are normally estimated separately for gaseous and liquid discharge pathways. Simple summation of these doses would tend to overestimate doses actually received. Three different methods of combining the effects of both types of discharge in an integrated assessment are considered and ranked according to their ease of application, transparency, scientific rigour and presentational issues. A single integrated assessment method is then chosen for further study. Doses are calculated for surveillance data for the calendar year 2000 and compared with those from the existing RIFE method.

  5. Using ecosystem science to improve protection of the environment from radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bradshaw, C. [Stockholm University (Sweden); Brechignac, F. [IUR / IRSN (France); Barnthouse, L. [LWB Environmental Services Inc. (United States); Brown, J. [Norwegian Radiation Protection Authority - NRPA (Norway); Forbes, V. [University of Lincoln (United Kingdom); Kapustka, L. [LC LK Consultancy (Canada); Kautsky, U. [Svensk Kaernbraenslehantering AB - SKB (Sweden)

    2014-07-01

    The ecosystem approach (EA) involves considering the impacts of an anthropogenic stressor at the ecosystem level because this is usually the ultimate goal of environmental protection. As such, EA includes population, community and ecosystem effects, structural and functional effects, indirect effects due to ecological interactions between species, dynamic interactions, positive or negative feedback loops, and potential synergistic or antagonistic effects of multiple stressors (both anthropogenic and natural). All such effects better reflect the reality of the impact of a contamination scenario than if assessments are restricted to considering effects to individual organisms or species. Such effects may be greater or lesser than expected from studies of individual organisms or species, so not considering them may result in under- or overestimation of risk, respectively. EA is a term that is widely used in environmental assessment, management and legislation in a number of regulatory fields (e.g., radiation protection, chemicals legislation, fisheries policy, international biodiversity conventions). However, although its justification is now well established in a wide range of environment protection contexts, its practical use is still unclear due to poorly defined protection goals and assessment endpoints, making its implementation difficult. This paper presents the initial findings of a newly formed follow-up task group of the International Union of Radioecology whose aims are to identify ways to put the EA into practice when considering protection of the environment from radiation. Drawing on knowledge and experience from a range of fields, we summarise the types of ecosystem processes, goods and services that might be included when using this approach, the science that supports the use of the EA, and the methodological challenges that need to be addressed when implementing the EA in the field of radiation protection. Document available in abstract form only

  6. MagRad: A code to optimize the operation of superconducting magnets in a radiation environment

    Energy Technology Data Exchange (ETDEWEB)

    Yeaw, Christopher T. [Univ. of Wisconsin, Madison, WI (United States)

    1995-01-01

    A powerful computational tool, called MagRad, has been developed which optimizes magnet design for operation in radiation fields. Specifically, MagRad has been used for the analysis and design modification of the cable-in-conduit conductors of the TF magnet systems in fusion reactor designs. Since the TF magnets must operate in a radiation environment which damages the material components of the conductor and degrades their performance, the optimization of conductor design must account not only for start-up magnet performance, but also shut-down performance. The degradation in performance consists primarily of three effects: reduced stability margin of the conductor; a transition out of the well-cooled operating regime; and an increased maximum quench temperature attained in the conductor. Full analysis of the magnet performance over the lifetime of the reactor includes: radiation damage to the conductor, stability, protection, steady state heat removal, shielding effectiveness, optimal annealing schedules, and finally costing of the magnet and reactor. Free variables include primary and secondary conductor geometric and compositional parameters, as well as fusion reactor parameters. A means of dealing with the radiation damage to the conductor, namely high temperature superconductor anneals, is proposed, examined, and demonstrated to be both technically feasible and cost effective. Additionally, two relevant reactor designs (ITER CDA and ARIES-II/IV) have been analyzed. Upon addition of pure copper strands to the cable, the ITER CDA TF magnet design was found to be marginally acceptable, although much room for both performance improvement and cost reduction exists. A cost reduction of 10-15% of the capital cost of the reactor can be achieved by adopting a suitable superconductor annealing schedule. In both of these reactor analyses, the performance predictive capability of MagRad and its associated costing techniques have been demonstrated.

  7. Role of the UV external radiation field on the presence of astrophysical ices in protostellars environments

    Science.gov (United States)

    Robson Monteiro Rocha, Will; Pilling, Sergio

    2016-07-01

    The astrophysical ices survival is directly related with the temperature and ionizing radiation field in protostellars environments such as disks and envelopes. Computational models has shown that pure volatile molecules like CO and CH _{4} should survive only inside densest regions of molecular clouds or protoplanetary disks On the other hand, solid molecules such as H _{2}O and CH _{3}OH can be placed around 5 - 10 AU from the central protostar. Unlike of the previous models, we investigate the role of the UV external radiation field on the presence of ices in disks and envelopes. Once that a star-forming region is composed by the formation of many protostars, the external radiation field should be an important component to understand the real localization of the ices along the sight line. To address this topic it was employed the radiative transfer code RADMC-3D based on the Monte Carlo method. The code was used to model the spectrum and the near-infrared image of Elias 29. The initial parameters of the disk and envelope was taken from our previous paper (Rocha & Pilling (2015), ApJ 803:18). The opacities of the ices were calculated from the complex refractive index obtained at laboratory experiments perfomed at Grand Accélerateur National d'Íons Lourds (GANIL), by using the NKABS code from Rocha & Pilling (2014), SAA 123:436. The partial conclusions that we have obtained shows that pure CO volatile molecule cannot be placed at disk or envelope of Elias 29, unlike shown in our paper about Elias 29. Once it was observed in Elias 29 spectrum obtained with Infrared Space Observatory (ISO) between 2.5 - 190 μm, this molecule should be placed in foreground molecular clouds or trapped in the water ice matrix. The next calculations will be able to show where are placed the ices such as CH _{3}OH and CH _{3}CHO observed in Elias 29 spectrum.

  8. Addressing ecological effects of radiation on populations and ecosystems to improve protection of the environment against radiation: Agreed statements from a Consensus Symposium☆

    Science.gov (United States)

    Bréchignac, François; Oughton, Deborah; Mays, Claire; Barnthouse, Lawrence; Beasley, James C.; Bonisoli-Alquati, Andrea; Bradshaw, Clare; Brown, Justin; Dray, Stéphane; Geras’kin, Stanislav; Glenn, Travis; Higley, Kathy; Ishida, Ken; Kapustka, Lawrence; Kautsky, Ulrik; Kuhne, Wendy; Lynch, Michael; Mappes, Tapio; Mihok, Steve; Møller, Anders P.; Mothersill, Carmel; Mousseau, Timothy A.; Otaki, Joji M.; Pryakhin, Evgeny; Rhodes, Olin E.; Salbu, Brit; Strand, Per; Tsukada, Hirofumi

    2016-01-01

    This paper reports the output of a consensus symposium organized by the International Union of Radioecology in November 2015. The symposium gathered an academically diverse group of 30 scientists to consider the still debated ecological impact of radiation on populations and ecosystems. Stimulated by the Chernobyl and Fukushima disasters’ accidental contamination of the environment, there is increasing interest in developing environmental radiation protection frameworks. Scientific research conducted in a variety of laboratory and field settings has improved our knowledge of the effects of ionizing radiation on the environment. However, the results from such studies sometimes appear contradictory and there is disagreement about the implications for risk assessment. The Symposium discussions therefore focused on issues that might lead to different interpretations of the results, such as laboratory versus field approaches, organism versus population and ecosystemic inference strategies, dose estimation approaches and their significance under chronic exposure conditions. The participating scientists, from across the spectrum of disciplines and research areas, extending also beyond the traditional radioecology community, successfully developed a constructive spirit directed at understanding discrepancies. From the discussions, the group has derived seven consensus statements related to environmental protection against radiation, which are supplemented with some recommendations. Each of these statements is contextualized and discussed in view of contributing to the orientation and integration of future research, the results of which should yield better consensus on the ecological impact of radiation and consolidate suitable approaches for efficient radiological protection of the environment. PMID:27058410

  9. Addressing ecological effects of radiation on populations and ecosystems to improve protection of the environment against radiation: Agreed statements from a Consensus Symposium.

    Science.gov (United States)

    Bréchignac, François; Oughton, Deborah; Mays, Claire; Barnthouse, Lawrence; Beasley, James C; Bonisoli-Alquati, Andrea; Bradshaw, Clare; Brown, Justin; Dray, Stéphane; Geras'kin, Stanislav; Glenn, Travis; Higley, Kathy; Ishida, Ken; Kapustka, Lawrence; Kautsky, Ulrik; Kuhne, Wendy; Lynch, Michael; Mappes, Tapio; Mihok, Steve; Møller, Anders P; Mothersill, Carmel; Mousseau, Timothy A; Otaki, Joji M; Pryakhin, Evgeny; Rhodes, Olin E; Salbu, Brit; Strand, Per; Tsukada, Hirofumi

    2016-07-01

    This paper reports the output of a consensus symposium organized by the International Union of Radioecology in November 2015. The symposium gathered an academically diverse group of 30 scientists to consider the still debated ecological impact of radiation on populations and ecosystems. Stimulated by the Chernobyl and Fukushima disasters' accidental contamination of the environment, there is increasing interest in developing environmental radiation protection frameworks. Scientific research conducted in a variety of laboratory and field settings has improved our knowledge of the effects of ionizing radiation on the environment. However, the results from such studies sometimes appear contradictory and there is disagreement about the implications for risk assessment. The Symposium discussions therefore focused on issues that might lead to different interpretations of the results, such as laboratory versus field approaches, organism versus population and ecosystemic inference strategies, dose estimation approaches and their significance under chronic exposure conditions. The participating scientists, from across the spectrum of disciplines and research areas, extending also beyond the traditional radioecology community, successfully developed a constructive spirit directed at understanding discrepancies. From the discussions, the group has derived seven consensus statements related to environmental protection against radiation, which are supplemented with some recommendations. Each of these statements is contextualized and discussed in view of contributing to the orientation and integration of future research, the results of which should yield better consensus on the ecological impact of radiation and consolidate suitable approaches for efficient radiological protection of the environment.

  10. Short and long term ionizing radiation effects on charge-coupled devices in radiation environment of high-intensity heavy ion accelerators

    Science.gov (United States)

    Belousov, A.; Mustafin, E.; Ensinger, W.

    2012-11-01

    Radiation effects on semiconductor devices is a topical issue for high-intensity accelerator projects. In particular it concerns Charge-Coupled Device (CCD) cameras, which are widely used for beam profile monitoring and surveillance in high radiation environment. One should have a clear idea of short and long term radiation effects on such devices. To study these effects, a CCD camera was placed in positions less than half meter away from beam loss point. Primary heavy ion beam of 0.95GeV/n Uranium was dumped into a thick aluminium target creating high fluences of secondary particles (e.g., gammas, neutrons, protons). Effects of these particles on CCD camera were scored with LabView based acquisition software. Monte Carlo calculations with FLUKA code were performed to obtain fluence distributions for different particles and make relevant comparisons. Long term total ionising dose effects are represented by dark current increase, which was scored throughout experiment. Instant radiation effects are represented by creation of charge in CCD cells by ionising particles. Relation of this charge to beam intensity was obtained for different camera positions and fluences within 5 orders of magnitude ranges. With high intensities this charge is so high that it may dramatically influence data obtained from CCD camera used in high radiation environment. The linearity of described above relation confirms linear response of CCD to ionizing radiation. It gives an opportunity to find a new application to CCD cameras as beam loss monitors (BLM).

  11. Investigation of innovative radiation imaging method and system for radiological environments

    Science.gov (United States)

    Nguyen, H.; Joung, J.; Kim, Y.; Lee, K.

    2017-03-01

    We have developed a novel imaging method that can be applied to most applications in the field of radiological environment imaging. It resolves either two-dimensional (2D) or three-dimensional (3D) distributions of radioactive sources in applications for homeland security, environmental monitoring, radiation contamination monitoring, baggage inspection, nuclear power plant monitoring, and more. The proposed imaging method uses a simple detector configured as a radiation-counting detector with spectroscopic capabilities. The detector module consists of two components: a flat field-of-view (FOV) collimator with a 30° FOV opening and a typical single-channel radiation detector made of a 2 in.×2 in. NaI(Tl) scintillator coupled to a 2 in photomultiplier tube (PMT). This simple detector module makes it possible to develop a cost-effective imaging system and provide design freedom in extending the system configuration to include one-dimensional (1D) or 2D detector-array shapes to meet the needs of various applications. One of most distinctive features of the new imaging method is that it uses only a pair of 2D projections to obtain a 3D reconstruction. The projections are measured by the proposed detector module at two positions orthogonal to one another; the measured projections are manipulated to enhance the resolution of the reconstructed 3D image. The imaging method comprises several steps performed consecutively: projection measurement, energy re-binning, projection separation, resolution and attenuation recovery, image reconstruction, and image consolidation and quantitative analysis. The resolution and attenuation recovery step provides the most distinctive and important processing by which the poor quality of projection data is enhanced. Such poor quality is mainly due to the use of a simple detector with a wide-opening flat FOV collimator. Simulation and experimental studies have been conducted to validate the proposed method. In this investigation, we

  12. Markedly enhanced direct radiative forcing of black carbon particles under polluted urban environments

    Science.gov (United States)

    Peng, Jianfei; Hu, Min; Guo, Song; Du, Zhuofei; Zheng, Jing; Shang, Dongjie; Zamora, Misti; Zeng, Liming; Shao, Min; Wu, Yusheng; Zheng, Jun; Wang, Yuan; Collins, Don; Zhang, Renyi

    2016-04-01

    Black carbon (BC) particles, produced from incomplete fossil fuel combustion and biomass burning, are ubiquitous in the atmosphere and have profound impacts on air quality, human health, weather, and climate. For example, in areas identified as aerosol hotspots, which include many urban centers and megacities worldwide, solar heating by BC particles has been shown to be comparable to warming due to the greenhouse gases2. Although BC represents a key short-lived climate forcer, its direct radiative forcing remains highly uncertain. In particular, the available results of absorption enhancement of BC particles during atmospheric aging are conflicting from the previous studies, leading to a large uncertainty in global radiative transfer calculation. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China and Houston, US, using a novel chamber approach. BC aging exhibits two distinct stages - initial transformation from a fractal to spherical morphology with little absorption variation and the subsequent growth of fully compact particles with a maximum absorption enhancement factor of 2.4. The variation in BC direct radiative forcing is highly dependent of the rate and timescale of aging, with an estimated increase of 0.45 (0.21 - 0.80) W m-2 from fresh to fully aged particles. Our results reveal a high climatic impact in polluted environments due to rapid aging and a clear distinction between urban cities in developed and developing countries for BC particles, highlighting a larger than recognized co-benefit in air quality improvement and climate protection by BC mediation.

  13. Nuclear Radiation Fields on the Mars Surface: Risk Analysis for Long-term Living Environment

    Science.gov (United States)

    Anderson, Brooke M.; Clowdsley, Martha S.; Qualls, Garry D.; Nealy, John E.

    2005-01-01

    Mars, our nearest planet outward from the sun, has been targeted for several decades as a prospective site for expanded human habitation. Background space radiation exposures on Mars are expected to be orders of magnitude higher than on Earth. Recent risk analysis procedures based on detailed dosimetric techniques applicable to sensitive human organs have been developed along with experimental data regarding cell mutation rates resulting from exposures to a broad range of particle types and energy spectra. In this context, simulated exposure and subsequent risk for humans in residence on Mars are examined. A conceptual habitat structure, CAD-modeled with duly considered inherent shielding properties, has been implemented. Body self-shielding is evaluated using NASA standard computerized male and female models. The background environment is taken to consist not only of exposure from incident cosmic ray ions and their secondaries, but also include the contribution from secondary neutron fields produced in the tenuous atmosphere and the underlying regolith.

  14. Radiative Transfer Model of Dust Attenuation Curves in Clumpy, Galactic Environments

    CERN Document Server

    Seon, Kwang-Il

    2016-01-01

    The attenuation of starlight by dust in galactic environments is investigated through models of radiative transfer in a spherical, clumpy ISM. Extinction properties for MW, LMC, and SMC dust types are considered. It is illustrated that the attenuation curves are primarily determined by the wavelength dependence of absorption rather than by the underlying extinction (absorption+scattering) curve. Attenuation curves consistent with the "Calzetti attenuation curve" are found by assuming the silicate-carbonaceous dust model for the MW, but with the 2175A absorption bump suppressed or absent. The discrepancy between our results and previous work that claimed the SMC-type dust to be the most likely origin of the Calzetti curve is ascribed to the difference in adopted albedos; this study uses the theoretically calculated albedos whereas the previous ones adopted empirically derived albedos from observations of reflection nebulae. It is also found that the model attenuation curves calculated with the MW dust are well...

  15. Habitability in High Radiation Environments: The Case for Gaia at Europa

    Science.gov (United States)

    Cooper, J. F.

    2004-12-01

    In the paper of Cooper et al. (2001) we concluded, in relation to our work on magnetospheric irradiation of Europa and the other icy galilean moons of Jupiter, that 'icy satellites with significant heat, irradiation, and subsurface water resources may provide common abodes for life throughout the universe'. This expanded the original proposal of Chyba (2000) and his later works that radiolytic production of oxidants and simple hydrocarbons on Europa's icy surface could support evolution and survival of life within a Europan subsurface ocean. In the general case of icy planets and moons the radiation environment does not have to interact directly with the surface but could also provide energy for life through radiation-induced chemistry in thick atmospheres chemically coupled to icy surfaces with hydrocarbon reservoirs as on Titan. The Gaia model for Earth implies that the entire planet operates with atmospheric, geologic, and geochemical processes conducive to life. Essential requirements for Gaia are an oxidizing atmospheric environment at planetary surfaces, where oxidants like molecular oxygen are produced by radiation processes (mediated by photosynthetic chemistry on Earth but more directly produced by radiolysis on Europa), reservoirs of liquid water and hydrocarbons on or below the surface, other reduced materials in the interior, and geologic processes which drive chemical exchange between the chemically oxidized surface and reduced interior environments. At Europa a thin oxygen atmosphere is observed and arises from magnetospheric interaction, and there is much evidence for active resurfacing likely related to solid-state convection and diapiric processes within a thick crust of soft ice overlying a liquid ocean. These processes on Europa are analogous to that of the tectonic conveyer belt that continually recycles carbon, oxygen, and other essential materials for life between the atmosphere, surface, and interior on Earth. The ice crust at Europa could be

  16. Continuous electromagnetic radiation monitoring in the environment: analysis of the results in Greece.

    Science.gov (United States)

    Manassas, Athanasios; Boursianis, Achilles; Samaras, Theodoros; Sahalos, John N

    2012-09-01

    Non-ionising radiation-monitoring networks were initiated as a result of the public concerns about the potential health effects from telecommunication emissions. In the present study, the data acquired from such networks in Greece are used to assess the changes in the outdoor electromagnetic environment with respect to location and time. The study shows that there is a statistically significant difference between the urban (median electric field: 1.1 V m(-1)) and the rural (median electric field: 0.3 V m(-1)) installations of monitoring units and also shows that there is a median diurnal variation (daily maximum to minimum) of 20.2 and 33.8 % for the broadcasting and mobile telecommunication emissions, respectively. Moreover, there is a difference in the electric field between daytime and night, but not between morning and afternoon. The results are in line with previously published data from spot measurements, monitoring networks and personal exposimeter studies performed in several European countries.

  17. Stimuli responsive deswelling of radiation synthesized collagen hydrogel in simulated physiological environment.

    Science.gov (United States)

    Zhang, Xiangmei; Xu, Ling; Wei, Shicheng; Zhai, Maolin; Li, Jiuqiang

    2013-08-01

    Collagen hydrogels were prepared via radiation crosslinking. The simulated physiological environmental effects related to their biomedical applications on the volume phase transition of collagen hydrogel were studied, that is stimuli response to ions, temperature, and pH. The deswelling behavior of collagen hydrogel depends on the salt concentration, temperature, pH, and the hydrogel preparation procedure. Meanwhile, hydrogel structure related to the volume phase transition was investigated by FTIR, fluorescence spectrum, and HR-MAS NMR. Deswelling in salt solution caused little change on collagen conformation, and a denser network led to more significant tyrosine-derived fluorescence quenching. Hydrogen bonding between hydrated water and collagen polypeptide chain was dissociated and the activity of hydrophobic side chain increased, inducing a higher extent of contraction with the increasing of salt concentration. Moreover, salt solution treatments weakened the electrostatic interactions, side chains interactions, and hydrogen bonding of collagen hydrogel, which reduced the thermal stability of collagen hydrogel. Comparing with cell-free collagen hydrogel contraction, fibroblasts did not aggravate contraction of collagen hydrogel significantly. This study elucidated the deswelling mechanism of radiation crosslinked collagen hydrogel in simulated physiological environment and provides strategies for controlling the stimuli response of collagen hydrogel in biomedical application.

  18. Beam test results of CMS RPCs at high eta region under high-radiation environment

    CERN Document Server

    Park, S; Bahk, S Y; Hong, B; Hong, S J; Kang, D H; Kang, T I; Kim, T J; Kim, Y J; Kim, Y U; Koo, D G; Lee, H W; Lee, K S; Lee, S J; Lim, J K; Moon, D H; Nam, S K; Oh, J K; Park, W J; Rhee, J T; Ryu, M S; Shim, H H; Sim, K S

    2004-01-01

    The Compact Muon Solenoid (CMS) forward resistivity plate chambers (RPCs) at the high eta region must be operated in presence of a radiation-induced rate as high as 1 kHz/cm**2. It is still unknown if the RPCs coated with linseed oil can be operated under such a high- radiation environment over the lifetime of CMS. Non-oiled RPCs may be one of the options since phenolic or melamine-coated bakelite is chemically stabler than linseed oil. We have constructed oiled and non-oiled RPCs at the high eta region of CMS using phenolic bakelite and tested them in the Gamma Irradiation Facility at CERN. While both RPCs show the same characteristics in the efficiency and the strip multiplicity, the non-oiled RPC generates an intrinsic noise rate of 50 Hz/cm**2, compared to only 5 Hz/cm**2 for the oiled RPC, both at 10.0kV which is about 100 V above the 95% knee of the efficiency curve.

  19. Thermal Analysis of a Finite Element Model in a Radiation Dominated Environment

    Science.gov (United States)

    Page, Arthur T.

    2001-07-01

    This paper presents a brief overview of thermal analysis, evaluating the University of Arizona mirror design, for the Next Generation Space Telescope (NGST) Pre-Phase A vehicle concept. Model building begins using Thermal Desktop(TM), by Cullimore and Ring Technologies, to import a NASTRAN bulk data file from the structural model of the mirror assembly. Using AutoCAD(R) capabilities, additional surfaces are added to simulate the thermal aspects of the problem which, for due reason, are not part of the structural model. Surfaces are then available to accept thermophysical and thermo-optical properties. Thermal Desktop(TM) calculates radiation conductors using Monte Carlo simulations. Then Thermal Desktop(TM) generates the SINDA input file having a one-to-one correspondence with the NASTRAN node and element definitions. A model is now available to evaluate the mirror design in the radiation dominated environment, conduct parametric trade studies of the thermal design, and provide temperatures to the finite element structural model.

  20. A temporal forecast of radiation environments for future space exploration missions.

    Science.gov (United States)

    Kim, Myung-Hee Y; Cucinotta, Francis A; Wilson, John W

    2007-06-01

    The understanding of future space radiation environments is an important goal for space mission operations, design, and risk assessment. We have developed a solar cycle statistical model in which sunspot number is coupled to space-related quantities, such as the galactic cosmic radiation (GCR) deceleration potential (phi) and the mean occurrence frequency of solar particle events (SPEs). Future GCR fluxes were derived from a predictive model, in which the temporal dependence represented by phi was derived from GCR flux and ground-based Climax neutron monitor rate measurements over the last four decades. These results showed that the point dose equivalent inside a typical spacecraft in interplanetary space was influenced by solar modulation by up to a factor of three. It also has been shown that a strong relationship exists between large SPE occurrences and phi. For future space exploration missions, cumulative probabilities of SPEs at various integral fluence levels during short-period missions were defined using a database of proton fluences of past SPEs. Analytic energy spectra of SPEs at different ranks of the integral fluences for energies greater than 30 MeV were constructed over broad energy ranges extending out to GeV for the analysis of representative exposure levels at those fluences. Results will guide the design of protection systems for astronauts during future space exploration missions.

  1. Design strength evaluation of RC beams under radiation environments for nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Won-Hee [Institute for Infrastructure Engineering, University of Western Sydney, Penrith, NSW 2751 (Australia); Kwon, Tae-Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Hyeong-Tae [Department of Civil and Environmental Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Park, Kyoungsoo, E-mail: k-park@yonsei.ac.kr [Department of Civil and Environmental Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2016-05-15

    Neutron irradiation changes the behavior of construction materials such as strength and ductility, and thus structural design equations or their safety margins should accordingly be updated for the design of nuclear power plants (NPP) under irradiation. However, current design codes do not account for such changes in material strength. In this study, a framework is proposed to evaluate the change of the safety margins in design equations of reinforced concrete (RC) flexural members under radiation environments. Material strength changes are approximated on the basis of a collected test database, and the design strengths of RC beams are evaluated considering these material strength changes. The evaluation results demonstrate that the design strength of an under-reinforced flexural member can increase while the design strength of an over-reinforced member generally decreases. These results are associated with the material strength changes such that the yield strength of steel increases and the compressive strength of concrete decreases with the fluence of neutron radiation. Current NPP design codes need to further consider this un-conservative design possibility due to the design strength reduction of flexural members under irradiation.

  2. Hollow core and other infrared waveguides for instrumentation in intense radiation environments.

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, Jonathan David

    2007-11-01

    The purpose of this LDRD was to study the effect of steady-state neutron and gamma irradiation on the transmission of waveguides designed to operate well in the near- or mid-IR region of the electromagnetic spectrum. In this context, near-IR refers to the region between 1.3 {mu}m and about 2.4 {mu}m, and mid-IR between 3.0 {mu}m and 4.5 {mu}m. Such radiation environments could exist in nuclear power plants or nuclear weapons. Pulsed and steady-state radiation effects had been extensively studied on silica-based optical fibers because they have been the most readily available, most widely used in communications and sensing, and the least expensive. However, silica-based fibers do not transmit well beyond about 1.8 {mu}m and they are virtually opaque in the mid-IR. The mid-IR, as defined above, and beyond, is where vibrational spectroscopy is carried out. This type of sensing is one important application of infrared optical fibers.

  3. Interactive visual intervention planning in particle accelerator environments with ionizing radiation

    CERN Document Server

    Fabry, Thomas

    Radiation is omnipresent. It has many interesting applications: in medicine, where it allows curing and diagnosing patients; in communication, where modern communication systems make use of electromagnetic radiation; and in science, where it is used to discover the structure of materials; to name a few. Physically, radiation is a process in which particles or waves travel through any kind of material, usually air. Radiation can be very energetic, in which case it can break the atoms of ordinary matter (ionization). If this is the case, radiation is called ionizing. It is known that ionizing radiation can be far more harmful to living beings than non-ionizing radiation. In this dissertation, we are concerned with ionizing radiation. Naturally occurring ionizing radiation in the form of radioactivity is a most natural phenomenon. Almost everything is radioactive: there is radiation emerging from the soil, it is in the air, and the whole planet is constantly undergoing streams of energetic cosmic radiation. Sinc...

  4. Complex composite engineering architectures for nuclear and high-radiation environments

    Energy Technology Data Exchange (ETDEWEB)

    Kornreich, Drew E [Los Alamos National Laboratory; Vaidya, Rajendra U [Los Alamos National Laboratory; Ammerman, Curtt N [Los Alamos National Laboratory

    2010-01-01

    Integrated Computational Materials Engineering (ICME) is a novel overarching approach to bridge length and time scales in computational materials science and engineering. This approach integrates all elements of multi-scale modeling (including various empirical and science-based models) with materials informatics to provide users the opportunity to tailor material selections based on stringent application needs. Typically, materials engineering has focused on structural requirements (stress, strain, modulus, fracture toughness etc.) while multi-scale modeling has been science focused (mechanical threshold strength model, grain-size models, solid-solution strengthening models etc.). Materials informatics (mechanical property inventories) on the other hand, is extensively data focused. All of these elements are combined within the framework of ICME to create architecture for the development, selection and design new composite materials for challenging environments. We propose development of the foundations for applying ICME to composite materials development for nuclear and high-radiation environments (including nuclear-fusion energy reactors, nuclear-fission reactors, and accelerators). We expect to combine all elements of current material models (including thermo-mechanical and finite-element models) into the ICME framework. This will be accomplished through the use of a various mathematical modeling constructs. These constructs will allow the integration of constituent models, which in tum would allow us to use the adaptive strengths of using a combinatorial scheme (fabrication and computational) for creating new composite materials. A sample problem where these concepts are used is provided in this summary.

  5. Integration of the Radiation Belt Environment Model Into the Space Weather Modeling Framework

    Science.gov (United States)

    Glocer, A.; Toth, G.; Fok, M.; Gombosi, T.; Liemohn, M.

    2009-01-01

    We have integrated the Fok radiation belt environment (RBE) model into the space weather modeling framework (SWMF). RBE is coupled to the global magnetohydrodynamics component (represented by the Block-Adaptive-Tree Solar-wind Roe-type Upwind Scheme, BATS-R-US, code) and the Ionosphere Electrodynamics component of the SWMF, following initial results using the Weimer empirical model for the ionospheric potential. The radiation belt (RB) model solves the convection-diffusion equation of the plasma in the energy range of 10 keV to a few MeV. In stand-alone mode RBE uses Tsyganenko's empirical models for the magnetic field, and Weimer's empirical model for the ionospheric potential. In the SWMF the BATS-R-US model provides the time dependent magnetic field by efficiently tracing the closed magnetic field-lines and passing the geometrical and field strength information to RBE at a regular cadence. The ionosphere electrodynamics component uses a two-dimensional vertical potential solver to provide new potential maps to the RBE model at regular intervals. We discuss the coupling algorithm and show some preliminary results with the coupled code. We run our newly coupled model for periods of steady solar wind conditions and compare our results to the RB model using an empirical magnetic field and potential model. We also simulate the RB for an active time period and find that there are substantial differences in the RB model results when changing either the magnetic field or the electric field, including the creation of an outer belt enhancement via rapid inward transport on the time scale of tens of minutes.

  6. Water and radiation use efficiencies of irrigated biomass sorghum in a Mediterranean environment

    Directory of Open Access Journals (Sweden)

    Pasquale Garofalo

    2011-06-01

    Full Text Available Biomass sorghum (Sorghum bicolor L. Moench is a crop that can be used for energy production in the bioethanol chain and a greater knowledge of its potential and response to irrigation water levels could help to assess its potential diffusion in Mediterranean areas. A two-year field experiment was carried out in Southern Italy; two irrigation regimes were compared in biomass sorghum, optimal watered (irrigation supplies greater than actual crop evapotranspiration, ETc and stressed watered (about 65% of the optimal one. Growth analysis, soil water content and aboveground dry biomass (ADM yield at harvest were measured and analyzed. Radiation use efficiency (RUE, irrigation (IWUE and water use efficiencies (WUE were also calculated. Seasonal water use ranged from 830 mm in the optimal treatment to 589 mm in the stressed one. Similarly, ADM proved to be statistically different between the two irrigation treatments (34.6 vs 19.8 t of dry matter ha–1. The RUE, calculated as the slope of the first order equation between dry biomass and intercepted photosynthetically active radiation along a crop cycle, showed an average of 2.84±0.65 g MJ–1. No statistical differences for IWUE and WUE were obtained between irrigation regimes (8.22 and 5.87 kg m–3, on average. The two years of experiment influenced IWUE and WUE (both larger in the rainier growing season, but not the RUE. The high RUE and WUE obtained values confirmed that biomass sorghum is a crop with considerable dry matter production efficiency. The experimental results suggest that the introduction of biomass sorghum in the cropping systems of Mediterranean environments as an alternative crop for energy purposes is feasible, but requires an adequate seasonal irrigation water supply (not less than 500 mm.

  7. Functional Traits in Parallel Evolutionary Radiations and Trait-Environment Associations in the Cape Floristic Region of South Africa.

    Science.gov (United States)

    Mitchell, Nora; Moore, Timothy E; Mollmann, Hayley Kilroy; Carlson, Jane E; Mocko, Kerri; Martinez-Cabrera, Hugo; Adams, Christopher; Silander, John A; Jones, Cynthia S; Schlichting, Carl D; Holsinger, Kent E

    2015-04-01

    Evolutionary radiations with extreme levels of diversity present a unique opportunity to study the role of the environment in plant evolution. If environmental adaptation played an important role in such radiations, we expect to find associations between functional traits and key climatic variables. Similar trait-environment associations across clades may reflect common responses, while contradictory associations may suggest lineage-specific adaptations. Here, we explore trait-environment relationships in two evolutionary radiations in the fynbos biome of the highly biodiverse Cape Floristic Region (CFR) of South Africa. Protea and Pelargonium are morphologically and evolutionarily diverse genera that typify the CFR yet are substantially different in growth form and morphology. Our analytical approach employs a Bayesian multiple-response generalized linear mixed-effects model, taking into account covariation among traits and controlling for phylogenetic relationships. Of the pairwise trait-environment associations tested, 6 out of 24 were in the same direction and 2 out of 24 were in opposite directions, with the latter apparently reflecting alternative life-history strategies. These findings demonstrate that trait diversity within two plant lineages may reflect both parallel and idiosyncratic responses to the environment, rather than all taxa conforming to a global-scale pattern. Such insights are essential for understanding how trait-environment associations arise and how they influence species diversification.

  8. The Effect of Dose Rate on Composite Durability When Exposed to a Simulated Long-Term Lunar Radiation Environment

    Science.gov (United States)

    Rojdev, Kristina; O'Rourke, Mary Jane; Hill, Charles; Nutt, Steven; Atwell, William

    2011-01-01

    Human exploration of space beyond low Earth orbit (LEO) requires a safe living and working environment for crew. Composite materials are one type of material being investigated by NASA as a multi-functional structural approach to habitats for long-term use in space or on planetary surfaces with limited magnetic fields and atmosphere. These materials provide high strength with the potential for decreased weight and increased radiation protection of crew and electronics when compared with conventional aluminum structures. However, these materials have not been evaluated in a harsh radiation environment, as would be experienced outside of LEO or on a planetary surface. Thus, NASA has been investigating the durability of select composite materials in a long-term radiation environment. Previously, NASA exposed composite samples to a simulated, accelerated 30-year radiation treatment and tensile stresses similar to those of a habitat pressure vessel. The results showed evidence of potential surface oxidation and enhanced cross-linking of the matrix. As a follow-on study, we performed the same accelerated exposure alongside an exposure with a decreased dose rate. The slower dose ]rate is comparable to a realistic scenario, although still accelerated. Strain measurements were collected during exposure and showed that with a fastdose rate, the strain decreased with time, but with a slow ]dose rate, the strain increased with time. After the radiation exposures, samples were characterized via tensile tests, flexure tests, Fourier Transform Infrared Spectroscopy (FTIR), and Differential Scanning Calorimetry (DSC). The results of these tests will be discussed.

  9. Space radiation environment prediction for VLSI microelectronics devices onboard a LEO satellite using OMERE-TRAD software

    Science.gov (United States)

    Sajid, Muhammad; Chechenin, N. G.; Torres, Frank Sill; Khan, E. U.; Agha, Shahrukh

    2015-07-01

    Space radiation environment at Low Earth Orbits (LEO) with perigee at 300 km, apogee at 600 km altitude having different orbital inclinations was modeled in the form of electrons and protons trapped in Van Allen Earth Radiation Belts (ERBs), heavy ions and protons in Galactic Cosmic Rays (GCRs), and Energetic Solar Particles (ESP) Events during solar maximum period. The co-relation between various shielding thicknesses and particles transport flux was analyzed for this specific orbit. We observed that there is an optimum shield thickness above which the attenuation of the transmitted flux of incident particles is negligible. To estimate the orbit average differential and integral fluxes to be encountered by onboard devices an appropriate radiation environment models were chosen in OMERE-TRAD toolkit and the impact of various shielding thickness for different orbital inclinations on integral Linear-Energy-Transfer (LET) spectra were determined.

  10. Radiation beamline testbeds for the simulation of planetary and spacecraft environments for human and robotic mission risk assessment

    Science.gov (United States)

    Wilkins, Richard

    The Center for Radiation Engineering and Science for Space Exploration (CRESSE) at Prairie View A&M University, Prairie View, Texas, USA, is establishing an integrated, multi-disciplinary research program on the scientific and engineering challenges faced by NASA and the inter-national space community caused by space radiation. CRESSE focuses on space radiation research directly applicable to astronaut health and safety during future long term, deep space missions, including Martian, lunar, and other planetary body missions beyond low earth orbit. The research approach will consist of experimental and theoretical radiation modeling studies utilizing particle accelerator facilities including: 1. NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory; 2. Proton Synchrotron at Loma Linda University Med-ical Center; and 3. Los Alamos Neutron Science Center (LANSCE) at Los Alamos National Laboratory. Specifically, CRESSE investigators are designing, developing, and building experimental test beds that simulate the lunar and Martian radiation environments for experiments focused on risk assessment for astronauts and instrumentation. The testbeds have been designated the Bioastronautics Experimental Research Testbeds for Environmental Radiation Nostrum Investigations and Education (BERT and ERNIE). The designs of BERT and ERNIE will allow for a high degree of flexibility and adaptability to modify experimental configurations to simulate planetary surface environments, planetary habitats, and spacecraft interiors. In the nominal configuration, BERT and ERIE will consist of a set of experimental zones that will simulate the planetary atmosphere (Solid CO2 in the case of the Martian surface.), the planetary surface, and sub-surface regions. These experimental zones can be used for dosimetry, shielding, biological, and electronic effects radiation studies in support of space exploration missions. BERT and ERNIE are designed to be compatible with the

  11. Radiation Beamline Testbeds for the Simulation of Planetary and Spacecraft Environments for Human and Robotic Mission Risk Assessment

    Science.gov (United States)

    Wilkins, Richard

    2010-01-01

    The Center for Radiation Engineering and Science for Space Exploration (CRESSE) at Prairie View A&M University, Prairie View, Texas, USA, is establishing an integrated, multi-disciplinary research program on the scientific and engineering challenges faced by NASA and the international space community caused by space radiation. CRESSE focuses on space radiation research directly applicable to astronaut health and safety during future long term, deep space missions, including Martian, lunar, and other planetary body missions beyond low earth orbit. The research approach will consist of experimental and theoretical radiation modeling studies utilizing particle accelerator facilities including: 1. NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory; 2. Proton Synchrotron at Loma Linda University Medical Center; and 3. Los Alamos Neutron Science Center (LANSCE) at Los Alamos National Laboratory. Specifically, CRESSE investigators are designing, developing, and building experimental test beds that simulate the lunar and Martian radiation environments for experiments focused on risk assessment for astronauts and instrumentation. The testbeds have been designated the Bioastronautics Experimental Research Testbeds for Environmental Radiation Nostrum Investigations and Education (BERT and ERNIE). The designs of BERT and ERNIE will allow for a high degree of flexibility and adaptability to modify experimental configurations to simulate planetary surface environments, planetary habitats, and spacecraft interiors. In the nominal configuration, BERT and ERIE will consist of a set of experimental zones that will simulate the planetary atmosphere (Solid CO2 in the case of the Martian surface.), the planetary surface, and sub-surface regions. These experimental zones can be used for dosimetry, shielding, biological, and electronic effects radiation studies in support of space exploration missions. BERT and ERNIE are designed to be compatible with the

  12. OPEN RADIATION: a collaborative project for radioactivity measurement in the environment by the public

    Science.gov (United States)

    Bottollier-Depois, Jean-François; Allain, E.; Baumont, G.; Berthelot, N.; Clairand, I.; Couvez, C.; Darley, G.; Henry, B.; Jolivet, T.; Laroche, P.; Lebau-Livé, A.; Lejeune, V.; Miss, J.; Monange, W.; Quéinnec, F.; Richet, Y.; Simon, C.; Trompier, F.; Vayron, F.

    2017-09-01

    After the Fukushima accident, initiatives emerged from the public to carry out themselves measurements of the radioactivity in the environment with various devices, among which smartphones, and to share data and experiences through collaborative tools and social networks. Such measurements have two major interests, on the one hand, to enable each individual of the public to assess his own risk regarding the radioactivity and, on the other hand, to provide "real time" data from the field at various locations, especially in the early phase of an emergency situation, which could be very useful for the emergency management. The objective of the OPENRADIATION project is to offer to the public the opportunity to be an actor for measurements of the radioactivity in the environment using connected dosimetric applications on smartphones. The challenge is to operate such a system on a sustainable basis in peaceful time and be useful in case of emergency. In "peaceful situation", this project is based on a collaborative approach with the aim to get complementary data to the existing ones, to consolidate the radiation background, to generate alerts in case of problem and to provide education & training and enhanced pedagogical approaches for a clear understanding of measures for the public. In case of emergency situation, data will be available "spontaneously" from the field in "real time" providing an opportunity for the emergency management and the communication with the public. … The practical objective is i) to develop a website centralising data from various systems/dosimeters, providing dose maps with raw and filtered data and creating dedicated areas for specific initiatives and exchanges of data and ii) to develop a data acquisition protocol and a dosimetric application using a connected dosimeter with a bluetooth connection. This project is conducted within a partnership between organisms' representative of the scientific community and associations to create links

  13. Dependence of the Martian radiation environment on atmospheric depth: Modeling and measurement

    Science.gov (United States)

    Guo, Jingnan; Slaba, Tony C.; Zeitlin, Cary; Wimmer-Schweingruber, Robert F.; Badavi, Francis F.; Böhm, Eckart; Böttcher, Stephan; Brinza, David E.; Ehresmann, Bent; Hassler, Donald M.; Matthiä, Daniel; Rafkin, Scot

    2017-02-01

    The energetic particle environment on the Martian surface is influenced by solar and heliospheric modulation and changes in the local atmospheric pressure (or column depth). The Radiation Assessment Detector (RAD) on board the Mars Science Laboratory rover Curiosity on the surface of Mars has been measuring this effect for over four Earth years (about two Martian years). The anticorrelation between the recorded surface Galactic Cosmic Ray-induced dose rates and pressure changes has been investigated by Rafkin et al. (2014) and the long-term solar modulation has also been empirically analyzed and modeled by Guo et al. (2015). This paper employs the newly updated HZETRN2015 code to model the Martian atmospheric shielding effect on the accumulated dose rates and the change of this effect under different solar modulation and atmospheric conditions. The modeled results are compared with the most up-to-date (from 14 August 2012 to 29 June 2016) observations of the RAD instrument on the surface of Mars. Both model and measurements agree reasonably well and show the atmospheric shielding effect under weak solar modulation conditions and the decline of this effect as solar modulation becomes stronger. This result is important for better risk estimations of future human explorations to Mars under different heliospheric and Martian atmospheric conditions.

  14. The effect of ionizing radiation on amino acids and bacterial spores in different geo- and cosmochemical environments

    Science.gov (United States)

    Kminek, Gerhard

    In this thesis I have investigated the impact of ionizing radiation from the environment on the stability of bacterial spores and amino acids. I measured the radiolysis constant of amino acids and the inactivation constant of bacterial spores. To put these results in the context of a natural setting, I have selected four different cases and calculated the radiation environment for meteorites, the Martian subsurface, terrestrial halite fluid inclusions, and fossil bones. Bacterial spores exhibit a remarkable resistance to adverse environments and are the best example for the long-term survival of life forms. On a molecular level, amino acids are of particular interest because of their importance in biochemistry and their stability in the environment. The significance of amino acids, however, goes back to a time before life existed. The exogenous delivery of amino acids by meteorites might have been essential to provide the required supply of organic molecules for the origin of life on the Earth. There is one common threat, however, to the preservation of amino acids and bacterial spores in all known terrestrial and extraterrestrial environments: ionizing radiation. Amino acids in meteorites are exposed to radiation from internal radioactivity and space radiation. I show that this radiation decomposes substantial amounts of amino acids over time, indicating a higher exogenous delivery of amino acids to the early Earth. The total radiodecomposition since the synthesis of amino acids is between 23 and 68%. Radiodecomposition induces a certain fractionation in favor of smaller amino acids. Fossil bones show a post-mortem uranium uptake. My results suggest a substantial radiodecomposition of amino acids on a 10 million year time scale. Age determination based on racemization of amino acids will be affected in fossil bones that are older than 1--30 million years. My results on the stability of bacterial spores in halite fluid inclusions and on Mars suggest that radiation

  15. Quantitative measurement of radiation pressure on a microcantilever in ambient environment

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Dakang; Munday, Jeremy N., E-mail: jnmunday@umd.edu [Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742 (United States); Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Garrett, Joseph L. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Department of Physics, University of Maryland, College Park, Maryland 20742 (United States)

    2015-03-02

    Light reflected off a material or absorbed within it exerts radiation pressure through the transfer of momentum. Micro/nano-mechanical transducers have become sensitive enough that radiation pressure can influence these systems. However, photothermal effects often accompany and overwhelm the radiation pressure, complicating its measurement. In this letter, we investigate the radiation force on an uncoated silicon nitride microcantilever in ambient conditions. We identify and separate the radiation pressure and photothermal forces through an analysis of the cantilever's frequency response. Further, by working in a regime where radiation pressure is dominant, we are able to accurately measure the radiation pressure. Experimental results are compared to theory and found to agree within the measured and calculated uncertainties.

  16. Premar-2: a Monte Carlo code for radiative transport simulation in atmospheric environments

    Energy Technology Data Exchange (ETDEWEB)

    Cupini, E. [ENEA, Centro Ricerche Ezio Clementel, Bologna, (Italy). Dipt. Innovazione

    1999-07-01

    The peculiarities of the PREMAR-2 code, aimed at radiation transport Monte Carlo simulation in atmospheric environments in the infrared-ultraviolet frequency range, are described. With respect to the previously developed PREMAR code, besides plane multilayers, spherical multilayers and finite sequences of vertical layers, each one with its own atmospheric behaviour, are foreseen in the new code, together with the refraction phenomenon, so that long range, highly slanted paths can now be more faithfully taken into account. A zenithal angular dependence of the albedo coefficient has moreover been introduced. Lidar systems, with spatially independent source and telescope, are allowed again to be simulated, and, in this latest version of the code, sensitivity analyses to be performed. According to this last feasibility, consequences on radiation transport of small perturbations in physical components of the atmospheric environment may be analyze and the related effects on searched results estimated. The availability of a library of physical data (reaction coefficients, phase functions and refraction indexes) is required by the code, providing the essential features of the environment of interest needed of the Monte Carlo simulation. Variance reducing techniques have been enhanced in the Premar-2 code, by introducing, for instance, a local forced collision technique, especially apt to be used in Lidar system simulations. Encouraging comparisons between code and experimental results carried out at the Brasimone Centre of ENEA, have so far been obtained, even if further checks of the code are to be performed. [Italian] Nel presente rapporto vengono descritte le principali caratteristiche del codice di calcolo PREMAR-2, che esegue la simulazione Montecarlo del trasporto della radiazione elettromagnetica nell'atmosfera, nell'intervallo di frequenza che va dall'infrarosso all'ultravioletto. Rispetto al codice PREMAR precedentemente sviluppato, il codice

  17. Evaluation and prediction of the degradation of space Si solar cells induced by a low-earth-orbit radiation environment

    Institute of Scientific and Technical Information of China (English)

    GAO Xin; YANG Sheng-Sheng; FENG Zhan-Zu; ZHANG Lei

    2012-01-01

    Space-graded silicon solar cells are evaluated by 1 MeV and 2 MeV electron-irradiation.The mean degradation of the maximum power (Pmax) is presented and analyzed.The degradation at both electron energies has been correlated with the displacement damage dose (Dd).A good linearity between the electron Dd and the mean Pmax degradation is obtained.The concept of Dd has also been used to predict the Si solar cell response in a low-earth-orbit (Altitude 799 km,Inclination 99°) radiation environment,considering the shielded effect of a 120 μm-thick silica coverglass on reducing the radiation.Compared with the on-orbit data from a Si solar array of a Chinese satellite (duration from April 2007 to July 2010),a good match can be found between the on-orbit data and the predicted results using Dd methodology,indicating the method is appropriate for evaluating the radiation damage of the solar cells,and also to provide a new technique for studying radiation effects on the optoelectronic detectors used in many high energy physics applications,where harsh radiation environments produce damage in optoelectronic device materials.

  18. Application of the modified Wheeler cap method for radiation efficiency measurement of balanced electrically small antennas in complex environment

    DEFF Research Database (Denmark)

    Zhang, Jiaying; Pivnenko, Sergey; Breinbjerg, Olav

    2010-01-01

    In this paper, application of a modified Wheeler cap method for the radiation efficiency measurement of balanced electrically small antennas is presented. It is shown that the limitations on the cavity dimension can be overcome and thus measurement in a large cavity is possible. The cavity loss...... is investigated, and a modified radiation efficiency formula that includes the cavity loss is introduced. Moreover, a modification of the technique is proposed that involves the antenna working complex environment inside the Wheeler Cap and thus makes possible measurement of an antenna close to a hand or head...

  19. The Diurnal Cycle of the Boundary Layer, Convection, Clouds, and Surface Radiation in a Coastal Monsoon Environment (Darwin Australia)

    Energy Technology Data Exchange (ETDEWEB)

    May, Peter T.; Long, Charles N.; Protat, Alain

    2012-08-01

    The diurnal variation of convection and associated cloud and radiative properties remains a significant issue in global NWP and climate models. This study analyzes observed diurnal variability of convection in a coastal monsoonal environment examining the interaction of convective rain clouds, their associated cloud properties, and the impact on the surface radiation and corresponding boundary layer structure during periods where convection is suppressed or active on the large scale. The analysis uses data from the Tropical Warm Pool International Cloud Experiment (TWP-ICE) as well as routine measurements from the Australian Bureau of Meteorology and the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program. Both active monsoonal and large-scale suppressed (buildup and break) conditions are examined and demonstrate that the diurnal variation of rainfall is much larger during the break periods and the spatial distribution of rainfall is very different between the monsoon and break regimes. During the active monsoon the total net radiative input to the surface is decreased by more than 3 times the amount than during the break regime - this total radiative cloud forcing is found to be dominated by the shortwave (SW) cloud effects because of the much larger optical thicknesses and persistence of long-lasting anvils and cirrus cloud decks associated with the monsoon regime. These differences in monsoon versus break surface radiative energy contribute to low-level air temperature differences in the boundary layer over the land surfaces.

  20. Improvement of the equivalent sphere model for better estimates of skin or eye dose in space radiation environments

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Z.W., E-mail: linz@ecu.ed [Department of Physics, East Carolina University, C-209 Howell Science Complex, Greenville, NC 27858-4353 (United States)

    2011-04-15

    It is often useful to get a quick estimate of the dose or dose equivalent of an organ, such as blood-forming organs, the eye or the skin, in a radiation field. Sometimes an equivalent sphere is used to represent the organ for this purpose. For space radiation environments, recently it has been shown that the equivalent sphere model does not work for the eye or the skin in solar particle event environments. In this study, we improve the representation of the eye and the skin using a two-component equivalent sphere model. Motivated by the two-peak structure of the body organ shielding distribution for the eye and the skin, we use an equivalent sphere with two radius parameters, for example a partial spherical shell of a smaller thickness over a proper fraction of the full solid angle combined with a concentric partial spherical shell of a larger thickness over the rest of the full solid angle, to represent the eye or the skin. We find that using an equivalent sphere with two radius parameters instead of one drastically improves the accuracy of the estimates of dose and dose equivalent in space radiation environments. For example, in solar particle event environments the average error in the estimate of the skin dose equivalent using an equivalent sphere with two radius parameters is about 8%, while the average error of the conventional equivalent sphere model using one radius parameter is around 100%.

  1. A Radiation Hard Multi-Channel Digitizer ASIC for Operation in the Harsh Jovian Environment

    Science.gov (United States)

    Aslam, Shahid; Aslam, S.; Akturk, A.; Quilligan, G.

    2011-01-01

    ultimately impact the surface of Europa after the mission is completed. The current JEO mission concept includes a range of instruments on the payload, to monitor dynamic phenomena (such as Io's volcanoes and Jupiters atmosphere), map the Jovian magnetosphere and its interactions with the Galilean satellites, and characterize water oceans beneath the ice shells of Europa and Ganymede. The payload includes a low mass (3.7 Kg) and low power (< 5 W) Thermal Instrument (TI) concept for measuring possible warm thermal anomalies on Europa s cold surface caused by recent (< 10,000 years) eruptive activity. Regions of anomalously high heat flow will be identified by thermal mapping using a nadir pointing, push-broom filter radiometer that provides far-IR imagery in two broad band spectral wavelength regions, 8-20 m and 20-100 m, for surface temperature measurements with better than a 2 K accuracy and a spatial resolution of 250 m/pixel obtained from a 100 Km orbit. The temperature accuracy permits a search for elevated temperatures when combined with albedo information. The spatial resolution is sufficient to resolve Europa's larger cracks and ridge axial valleys. In order to accomplish the thermal mapping, the TI uses sensitive thermopile arrays that are readout by a custom designed low-noise Multi-Channel Digitizer (MCD) ASIC that resides very close to the thermopile linear array outputs. Both the thermopile array and the MCD ASIC will need to show full functionality within the harsh Jovian radiation environment, operating at cryogenic temperatures, typically 150 K to 170 K. In the following, a radiation mitigation strategy together with a low risk Radiation-Hardened-By-Design (RHBD) methodology using commercial foundry processes is given for the design and manufacture of a MCD ASIC that will meet this challenge.

  2. High-performing simulations of the space radiation environment for the International Space Station and Apollo Missions

    Science.gov (United States)

    Lund, Matthew Lawrence

    The space radiation environment is a significant challenge to future manned and unmanned space travels. Future missions will rely more on accurate simulations of radiation transport in space through spacecraft to predict astronaut dose and energy deposition within spacecraft electronics. The International Space Station provides long-term measurements of the radiation environment in Low Earth Orbit (LEO); however, only the Apollo missions provided dosimetry data beyond LEO. Thus dosimetry analysis for deep space missions is poorly supported with currently available data, and there is a need to develop dosimetry-predicting models for extended deep space missions. GEANT4, a Monte Carlo Method, provides a powerful toolkit in C++ for simulation of radiation transport in arbitrary media, thus including the spacecraft and space travels. The newest version of GEANT4 supports multithreading and MPI, resulting in faster distributive processing of simulations in high-performance computing clusters. This thesis introduces a new application based on GEANT4 that greatly reduces computational time using Kingspeak and Ember computational clusters at the Center for High Performance Computing (CHPC) to simulate radiation transport through full spacecraft geometry, reducing simulation time to hours instead of weeks without post simulation processing. Additionally, this thesis introduces a new set of detectors besides the historically used International Commission of Radiation Units (ICRU) spheres for calculating dose distribution, including a Thermoluminescent Detector (TLD), Tissue Equivalent Proportional Counter (TEPC), and human phantom combined with a series of new primitive scorers in GEANT4 to calculate dose equivalence based on the International Commission of Radiation Protection (ICRP) standards. The developed models in this thesis predict dose depositions in the International Space Station and during the Apollo missions showing good agreement with experimental measurements

  3. Radiation-Hardened Memristor-based Memory for Extreme Environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA space exploration missions require radiation-hardened memory technologies that can survive and operate over a wide temperature range. Memristors...

  4. Composite Materials under Extreme Radiation and Temperature Environments of the Next Generation Nuclear Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Simos, N.

    2011-05-01

    In the nuclear energy renaissance, driven by fission reactor concepts utilizing very high temperatures and fast neutron spectra, materials with enhanced performance that exceeds are expected to play a central role. With the operating temperatures of the Generation III reactors bringing the classical reactor materials close to their performance limits there is an urgent need to develop and qualify new alloys and composites. Efforts have been focused on the intricate relations and the high demands placed on materials at the anticipated extreme states within the next generation fusion and fission reactors which combine high radiation fluxes, elevated temperatures and aggressive environments. While nuclear reactors have been in operation for several decades, the structural materials associated with the next generation options need to endure much higher temperatures (1200 C), higher neutron doses (tens of displacements per atom, dpa), and extremely corrosive environments, which are beyond the experience on materials accumulated to-date. The most important consideration is the performance and reliability of structural materials for both in-core and out-of-core functions. While there exists a great body of nuclear materials research and operating experience/performance from fission reactors where epithermal and thermal neutrons interact with materials and alter their physio-mechanical properties, a process that is well understood by now, there are no operating or even experimental facilities that will facilitate the extreme conditions of flux and temperature anticipated and thus provide insights into the behaviour of these well understood materials. Materials, however, still need to be developed and their interaction and damage potential or lifetime to be quantified for the next generation nuclear energy. Based on material development advances, composites, and in particular ceramic composites, seem to inherently possess properties suitable for key functions within the

  5. Protection of people and environment from radiation risk through good regulatory practice

    Science.gov (United States)

    Jais, Azlina Mohammad; Hassan, Najwa

    2017-01-01

    The term "good regulatory practice" has seen growing frequency of usage worldwide, especially since the 2011 Fukushima nuclear incident. However, the term appears quite ambiguous as it may mean differently to different people. This leads us to the first important question: what does "good regulatory practice" actually mean? When used in conjunction with the Fukushima incident, do we imply that there is an absence of "good regulatory practice" in the Japanese' Nuclear and Industry Safety Agency (NISA)? This is quite troubling. It is clear that the term should be defined formally so that our understanding of "good regulatory practice" can be standardized. There is still another important question beyond agreeing on what "good regulatory practice" is: is "good regulatory practice" specific to a region, or is it global? And is it applicable only to nuclear regulators, or to all types of regulators per se? This paper aims to deliberate on the above mentioned questions. Specifically, we hope to discuss the "good regulatory practice" for atomic energy activities in order to protect the people and the environment from radiation risk of such activities. By understanding what "good regulatory practice" truly means, a newcomer country such as Malaysia can quickly learn and adopt these practices so as to assure a competent national nuclear regulatory authority who will be responsible in ensuring the safety, security and safeguards of peaceful atomic energy activities in the country including nuclear liability. In understanding this concept, a holistic approach will be taken by looking into example of advanced and newcomer countries of various nuclear regulatory authorities all around the world. Then the paper will focus on the challenges that the current nuclear regulatory authority in Malaysia which is Atomic Energy Licensing Board has, its challenges to follow the concept of "good regulatory practice" and its ways to overcome it. This study explore the initiatives could be

  6. Mapping the Space Radiation Environment in LEO Orbit by the SATRAM Timepix Payload On Board the Proba-V Satellite

    Science.gov (United States)

    Granja, Carlos; Polansky, Stepan; Sospisil, Stanislav; Owens, Alan; Mellab, Karim

    2016-08-01

    The compact spacecraft payload SATRAM is operating in LEO orbit since 2013 on board the Proba-V satellite from ESA and provides high-resolution wide-range radiation monitoring of the satellite environment. Equipped with the pixel detector Timepix, the technology demonstration payload determines the composition (particle types) and spectral characterization (stopping power) of the mixed radiation field with quantum imaging sensitivity, charged particle tracking, energy loss and directionality capability. With a polar orbit (sun synchronous, 98° inclination) and altitude of 820 km the space radiation field is continuously sampled over the entire planet every few days. Results are given in the form of spatial- and time- correlated maps of dose rate and particle flux. Comparison is made between quiescent and geomagnetic storm activity periods.

  7. The charged particle radiation environment on Mars measured by MSL/RAD from November 15, 2015 to January 15, 2016

    Science.gov (United States)

    Ehresmann, Bent; Zeitlin, Cary J.; Hassler, Donald M.; Matthiä, Daniel; Guo, Jingnan; Wimmer-Schweingruber, Robert F.; Appel, Jan K.; Brinza, David E.; Rafkin, Scot C. R.; Böttcher, Stephan I.; Burmeister, Sönke; Lohf, Henning; Martin, Cesar; Böhm, Eckart; Reitz, Günther

    2017-08-01

    The Radiation Assessment Detector (RAD) on board the Mars Science Laboratory (MSL) Curiosity rover has been measuring the radiation environment in Gale crater on Mars since August, 2012. These first in-situ measurements provide an important data set for assessing the radiation-associated health risks for future manned missions to Mars. Mainly, the radiation field on the Martian surface stems from Galactic Cosmic Rays (GCRs) and secondary particles created by the GCRs' interactions with the Martian atmosphere and soil. RAD is capable of measuring differential particle fluxes for lower-energy ions and isotopes of hydrogen and helium (up to hundreds of MeV/nuc). Additionally, RAD also measures integral particle fluxes for higher energies of these ions. Besides providing insight on the current Martian radiation environment, these fluxes also present an essential input for particle transport codes that are used to model the radiation to be encountered during future manned missions to Mars. Comparing simulation results with actual ground-truth measurements helps to validate these transport codes and identify potential areas of improvements in the underlying physics of these codes. At the First Mars Radiation Modeling Workshop (June 2016 in Boulder, CO), different groups of modelers were asked to calculate the Martian surface radiation environment for the time of November 15, 2015 to January 15, 2016. These model results can then be compared with in-situ measurements of MSL/RAD conducted during the same time frame. In this publication, we focus on presenting the charged particle fluxes measured by RAD between November 15, 2015 and January 15, 2016, providing the necessary data set for the comparison to model outputs from the modeling workshop. We also compare the fluxes to initial GCR intensities, as well as to RAD measurements from an earlier time period (August 2012 to January 2013). Furthermore, we describe how changes and updates in RAD on board processing and the on

  8. Using the FLUKA Monte Carlo Code to Simulate the Interactions of Ionizing Radiation with Matter to Assist and Aid Our Understanding of Ground Based Accelerator Testing, Space Hardware Design, and Secondary Space Radiation Environments

    Science.gov (United States)

    Reddell, Brandon

    2015-01-01

    Designing hardware to operate in the space radiation environment is a very difficult and costly activity. Ground based particle accelerators can be used to test for exposure to the radiation environment, one species at a time, however, the actual space environment cannot be duplicated because of the range of energies and isotropic nature of space radiation. The FLUKA Monte Carlo code is an integrated physics package based at CERN that has been under development for the last 40+ years and includes the most up-to-date fundamental physics theory and particle physics data. This work presents an overview of FLUKA and how it has been used in conjunction with ground based radiation testing for NASA and improve our understanding of secondary particle environments resulting from the interaction of space radiation with matter.

  9. On the possibility of cosmic ray-induced ionizing radiation-powered life in subsurface environments in the Universe

    CERN Document Server

    Atri, Dimitra

    2015-01-01

    Photosynthesis is a highly efficient mechanism developed by terrestrial life to utilize the energy from photons of solar origin for biological use. Subsurface regions are isolated from the photosphere, and consequently are incapable of utilizing this energy. This opens up the opportunity for life to cultivate alternative mechanisms in order to take advantage of other available energy sources. Studies have shown that in subsurface environments, life can use energy generated from geochemical and geothermal processes to sustain a minimal metabolism. Another mechanism is radiolysis, in which particles emitted by radioactive substances are indirectly utilized for metabolism. One such example is the bacterium fueled by radiation, found 2 miles deep in a South African mine, which consumes hydrogen formed from particles emitted by radioactive U, Th and K present in rock. An additional source of radiation in the subsurface environments is secondary particles, such as muons generated by Galactic Cosmic Rays (GCRs). It ...

  10. Patient exposure and radiation environment of an extracorporeal shock wave lithotriptor system

    Energy Technology Data Exchange (ETDEWEB)

    Lin, P.J.; Hrejsa, A.F.

    1987-10-01

    Radiation exposures to the patient undergoing extracorporeal shock wave lithotripsy were assessed along with the scattered radiation levels around the lithotriptor systems. The data gathered from 2 Dornier lithotriptor systems suggest that the lead shieldings required for this particular make and model are minimal. Owing to the physical size of the lithotriptor system, the treatment room housing it may not require additional lead shielding when the walls are constructed with appropriate materials. Typical radiation exposures to the patient have been assessed from the experimental data. The total amount of radiation exposures a patient is likely to receive has been estimated to be approximately 26 roentgens, for example 21 roentgens from 3 to 4 minutes of fluoroscopic exposure and 5 roentgens from 8 frames of video spot filming. The scattered radiation has been found to be approximately 0.5 mR. per hour at 3 feet or 91 cm. from the center of the lithotriptor water tank.

  11. Scenario of a dirty bomb in an urban environment and acute management of radiation poisoning and injuries.

    Science.gov (United States)

    Chin, F K C

    2007-10-01

    In the new security environment, there is a clear and present danger of terrorists using non-conventional weapons to inflict maximum psychological and economic damage on their targets. This article examines two scenarios of radiation contamination and injury, one accidental in nature leading to environmental contamination, and another of deliberate intent resulting in injury and death. This article also discusses the management of injury from radiological dispersion devices or dirty bombs, with emphasis on the immediate aftermath as well as strategy recommendations.

  12. Design Issues for Using Magnetic Materials in Radiation Environments at Elevated Temperature

    Science.gov (United States)

    Bowman, Cheryl L.

    2013-01-01

    One of the challenges of designing motors and alternators for use in nuclear powered space missions is accounting for the effects of radiation. Terrestrial reactor power plants use distance and shielding to minimize radiation damage but space missions must economize volume and mass. Past studies have shown that sufficiently high radiation levels can affect the magnetic response of hard and soft magnetic materials. Theoretical models explaining the radiation-induced degradation have been proposed but not verified. This paper reviews the literature and explains the cumulative effects of temperature, magnetic-load, and radiation-level on the magnetic properties of component materials. Magnetic property degradation is very specific to alloy choice and processing history, since magnetic properties are very much entwined with specific chemistry and microstructural features. However, there is basic theoretical as well as supportive experimental evidence that the negative impact to magnetic properties will be minimal if the bulk temperature of the material is less than fifty percent of the Curie temperature, the radiation flux is low, and the demagnetization field is small. Keywords: Magnets, Permanent Magnets, Power Converters, Nuclear Electric Power Generation, Radiation Tolerance.

  13. Influence of nonequilibrium radiation and shape change on aerothermal environment of a Jovian entry body

    Science.gov (United States)

    Tiwari, S. N.; Subramanian, S. V.

    1981-01-01

    The influence of nonequilibrium radiative energy transfer and the effect of probe configuration changes on the flow phenomena around a Jovian entry body are investigated. The radiating shock layer flow is assumed to be axisymmetric, viscous, laminar and in chemical equilibrium. The radiative transfer equations are derived under nonequilibrium conditions which include multilevel energy transitions. The equilibrium radiative transfer analysis is performed with an existing nongray radiation model which accounts for molecular band, atomic line, and continuum transitions. The nonequilibrium results are obtained with and without ablation injection in the shock layer. The nonequilibrium results are found to be greatly influenced by the temperature distribution in the shock layer. In the absence of ablative products, the convective and radiative heating to the entry body are reduced under nonequilibrium conditions. The influence of nonequilibrium is found to be greater at higher entry altitudes. With coupled ablation and carbon phenolic injection, 16 chemical species are used in the ablation layer for radiation absorption. Equilibrium and nonequilibrium results are compared under peak heating conditions.

  14. Evaluation of standard radiation atmosphere aerosol models for a coastal environment

    Science.gov (United States)

    Whitlock, C. H.; Suttles, J. T.; Sebacher, D. I.; Fuller, W. H.; Lecroy, S. R.

    1986-01-01

    Calculations are compared with data from an experiment to evaluate the utility of standard radiation atmosphere (SRA) models for defining aerosol properties in atmospheric radiation computations. Initial calculations with only SRA aerosols in a four-layer atmospheric column simulation allowed a sensitivity study and the detection of spectral trends in optical depth, which differed from measurements. Subsequently, a more detailed analysis provided a revision in the stratospheric layer, which brought calculations in line with both optical depth and skylight radiance data. The simulation procedure allows determination of which atmospheric layers influence both downwelling and upwelling radiation spectra.

  15. Noise limitations of multiplier phototubes in the radiation environment of space

    Science.gov (United States)

    Viehmann, W.; Eubanks, A. G.

    1976-01-01

    The contributions of Cerenkov emission, luminescence, secondary electron emission, and bremsstrahlung to radiation-induced data current and noise of multiplier phototubes were analyzed quantitatively. Fluorescence and Cerenkov emission in the tube window are the major contributors and can quantitatively account for dark count levels observed in orbit. Radiation-induced noise can be minimized by shielding, tube selection, and mode of operation. Optical decoupling of windows and cathode (side-window tubes) leads to further reduction of radiation-induced dark counts, as does reducing the window thickness and effective cathode area, and selection of window/cathode combinations of low fluorescence efficiency. In trapped radiation-free regions of near-earth orbits and in free space, Cerenkov emission by relativistic particles contributes predominantly to the photoelectron yield per event. Operating multiplier phototubes in the photon (pulse) counting mode will discriminate against these large pulses and substantially reduce the dark count and noise to levels determined by fluorescence.

  16. A Review of NASA's Radiation-Hardened Electronics for Space Environments Project

    Science.gov (United States)

    Keys, Andrew S.; Adams, James H.; Patrick, Marshall C.; Johnson, Michael A.; Cressler, John D.

    2008-01-01

    NASA's Radiation Hardened Electronics for Space Exploration (RHESE) project develops the advanced technologies required to produce radiation hardened electronics, processors, and devices in support of the requirements of NASA's Constellation program. Over the past year, multiple advancements have been made within each of the RHESE technology development tasks that will facilitate the success of the Constellation program elements. This paper provides a brief review of these advancements, discusses their application to Constellation projects, and addresses the plans for the coming year.

  17. Evaluating a radiation monitor for mixed-field environments based on SRAM technology

    CERN Document Server

    Tsiligiannis, G; Bosio, A; Girard, P; Pravossoudovitch, S; Todri, A; Virazel, A; Mekki, J; Brugger, M; Wrobel, F; Saigne, F

    2014-01-01

    Instruments operating in particle accelerators and colliders are exposed to radiations that are composed of particles of different types and energies. Several of these instruments often embed devices that are not hardened against radiation effects. Thus, there is a strong need for mon- itoring the levels of radiation inside the mixed-field radiation areas, throughout different positions. Different metrics exist for measuring the radiation damage induced to electronic devices, such as the Total Ionizing Dose (TID), the Displacement Damage (DD) and of course the fluence of parti- cles for estimating the error rates of the electronic devices among other applications. In this paper, we propose an SRAM based monitor, that is used to define the fluence of High Energy Hadrons (HEH) by detecting Single Event Upsets in the memory array. We evaluated the device by testing it inside the H4IRRAD area of CERN, a test area that reproduces the radiation conditions inside the Large Hadron Collider (LHC) tunnel and its shield...

  18. Evaluating a radiation monitor for mixed-field environments based on SRAM technology

    Science.gov (United States)

    Tsiligiannis, G.; Dilillo, L.; Bosio, A.; Girard, P.; Pravossoudovitch, S.; Todri, A.; Virazel, A.; Mekki, J.; Brugger, M.; Wrobel, F.; Saigne, F.

    2014-05-01

    Instruments operating in particle accelerators and colliders are exposed to radiations that are composed of particles of different types and energies. Several of these instruments often embed devices that are not hardened against radiation effects. Thus, there is a strong need for monitoring the levels of radiation inside the mixed-field radiation areas, throughout different positions. Different metrics exist for measuring the radiation damage induced to electronic devices, such as the Total Ionizing Dose (TID), the Displacement Damage (DD) and of course the fluence of particles for estimating the error rates of the electronic devices among other applications. In this paper, we propose an SRAM based monitor, that is used to define the fluence of High Energy Hadrons (HEH) by detecting Single Event Upsets in the memory array. We evaluated the device by testing it inside the H4IRRAD area of CERN, a test area that reproduces the radiation conditions inside the Large Hadron Collider (LHC) tunnel and its shielded areas. By using stability estimation methods and presenting experimental data, we prove that this device is proper to be used for such a purpose.

  19. Environment

    DEFF Research Database (Denmark)

    Valentini, Chiara

    2017-01-01

    The term environment refers to the internal and external context in which organizations operate. For some scholars, environment is defined as an arrangement of political, economic, social and cultural factors existing in a given context that have an impact on organizational processes and structures....... For others, environment is a generic term describing a large variety of stakeholders and how these interact and act upon organizations. Organizations and their environment are mutually interdependent and organizational communications are highly affected by the environment. This entry examines the origin...... and development of organization-environment interdependence, the nature of the concept of environment and its relevance for communication scholarships and activities....

  20. Web-based description of the space radiation environment using the Bethe-Bloch model

    Science.gov (United States)

    Cazzola, Emanuele; Calders, Stijn; Lapenta, Giovanni

    2016-01-01

    Space weather is a rapidly growing area of research not only in scientific and engineering applications but also in physics education and in the interest of the public. We focus especially on space radiation and its impact on space exploration. The topic is highly interdisciplinary, bringing together fundamental concepts of nuclear physics with aspects of radiation protection and space science. We give a new approach to presenting the topic by developing a web-based application that combines some of the fundamental concepts from these two fields into a single tool that can be used in the context of advanced secondary or undergraduate university education. We present DREADCode, an outreach or teaching tool to rapidly assess the current conditions of the radiation field in space. DREADCode uses the available data feeds from a number of ongoing space missions (ACE, GOES-13, GOES-15) to produce a first order approximation of the radiation dose an astronaut would receive during a mission of exploration in deep space (i.e. far from the Earth’s shielding magnetic field and from the radiation belts). DREADCode is based on an easy-to-use GUI interface available online from the European Space Weather Portal (www.spaceweather.eu/dreadcode). The core of the radiation transport computation to produce the radiation dose from the observed fluence of radiation observed by the spacecraft fleet considered is based on a relatively simple approximation: the Bethe-Bloch equation. DREADCode also assumes a simplified geometry and material configuration for the shields used to compute the dose. The approach is approximate and sacrifices some important physics on the altar of rapid execution time, which allows a real-time operation scenario. There is no intention here to produce an operational tool for use in space science and engineering. Rather, we present an educational tool at undergraduate level that uses modern web-based and programming methods to learn some of the most important

  1. "BION-M" No.1 spacecraft radiation environment as observed in April-May 2013. Comparison with ISS data

    Science.gov (United States)

    Dachev, Tsvetan; Horneck, Gerda; Reitz, Guenther; Semkova, Jordanka; Schuster, Martin; Lebert, Michael; Malchev, Stefan; Tomov, Borislav; Matviichuk, Yury; Dimitrov, Plamen; Ivanova, Olga; Haeder, Donat-Peter; Bankov, Nikolai; Shurshakov, Vyacheslav; Benghin, Victor; K, Rositza

    Space radiation has been monitored in the period 19 April-13 May 2013 using RD3-B3 spectrometer-dosimeter on board the Russian recoverable satellite "BION-M" No.1. The instrument was mounted inside of the satellite pressurized volume together with biological objects and samples. RD3-B3 instrument is a battery operated version of the spare model of the R3D-B3 instrument developed and successfully worked on the ESA Biopan-6 facility on Foton M3 satellite in September 2007. Cosmic ionizing radiation has been monitored and separated in 256 deposited energy spectra, which were further used for determination of the absorbed dose rate and flux. The obtained history of accumulation and the daily and hourly values for the space radiation are presented in the paper ant they can contribute to a better understanding of the results from the biological experiments. Analogical data were obtained simultaneously on the International Space Station (ISS) using the Liulin-5 charged particle telescope. The paper summarizes the results for the global distribution of the Earth radiation environment at the altitude of the "BION-M" No.1 spacecraft and compares these data with the Liulin-5 data at the ISS and with AP/AE-8 MAX model.

  2. Measurement of Near Earth Radiation Environment in Japan—Overview and Plan—

    Science.gov (United States)

    Goka, Tateo; Matsumoto, Haruhisa

    2009-06-01

    The current status of measuring radiation using JAXA satellites is reviewed. Starting with Engineering Test Satellite-V (ETS-V; KIKU-5 in Japanese) in 1987, efforts to conduct radiation measurements in space have continued using almost all Japan Aerospace Exploration Agency (JAXA formerly NASDA) satellites (ETS-VI, ADEOS, ADEOS-II, MDS-1, DRTS (ongoing), and ALOS (ongoing)), in geostationary orbit (GEO), geostationary -transfer orbit (GTO), and low-Earth orbit (LEO). Electrons, protons, alpha particles, and heavy ions have been the main objects of study. Future plans for radiation monitoring in JAXA, including GOSAT, Jason-2 (in ollaboration with CNES), SmartSat (in collaboration with NICT), and ISS/JEM/Exposure Facility/SEDA-AP, are presented.

  3. Investigating Time and Spectral Dependence in Neutron Radiation Environments for Semiconductor Damage Studies

    Science.gov (United States)

    2014-09-18

    source of beta particles with radius , s, a distance, d, away from a detector with radius , a. The geometric factor, ξ, is dependent on the solid angle...parameters varied in sensitivity study. Units of D are cm2/s, units of E are eV, units of ν are s−1 and units of Radius are Å...as much of the neutron radiation (either cosmic or nuclear weapon induced) remains hard and the radiation pulse short. Also, the gamma flux from

  4. Illumination of the Air Environment Using Radiation of HF Broadcast Stations

    Science.gov (United States)

    Lutsenko, V. I.; Lutsenko, I. V.; Popov, I. V.

    2015-06-01

    We consider the possibility of using illumination of the HF broadcast stations for location of air objects. The relationships for estimation of the detection range are obtained and requirements for the degree of suppression of a direct signal from the broadcast station are determined. Spectral characteristics of the signals from HF broadcast stations are studied experimentally for different polarizations of the received radiation. The possibility of air object detection using the Doppler effect is shown. Theoretical estimates of the radar cross section of air objects for different polarizations of the incident radiation are given. It is found experimentally that the radar cross section is about the same for the vertical and horizontal polarizations.

  5. A Multi-Environment Thermal Control System With Freeze-Tolerant Radiator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future space exploration missions require advanced thermal control systems (TCS) to dissipate heat from spacecraft, rovers, or habitats to external environments. We...

  6. Observation of radiation environment in the International Space Station in 2012–March 2013 by Liulin-5 particle telescope

    Directory of Open Access Journals (Sweden)

    Semkova Jordanka

    2014-01-01

    Full Text Available Since June 2007 the Liulin-5 charged particle telescope, located in the spherical tissue-equivalent phantom of the MATROSHKA-R project onboard the International Space Station (ISS, has been making measurements of the local energetic particle radiation environment. From 27 December 2011 to 09 March 2013 measurements were conducted in and outside the phantom located in the MIM1 module of the ISS. In this paper Liulin-5 dose rates, due to galactic cosmic rays and South Atlantic Anomaly trapped protons, measured during that period are presented. Particularly, dose rates and particle fluxes for the radiation characteristics in the phantom during solar energetic particle (SEP events occurring in March and May 2012 are discussed. Liulin-5 SEP observations are compared with other ISS data, GOES proton fluxes as well as with solar energetic particle measurements obtained onboard the Mir space station during previous solar cycles.

  7. Preliminary design of CERN Future Circular Collider tunnel: first evaluation of the radiation environment in critical areas for electronics

    Science.gov (United States)

    Infantino, Angelo; Alía, Rubén García; Besana, Maria Ilaria; Brugger, Markus; Cerutti, Francesco

    2017-09-01

    As part of its post-LHC high energy physics program, CERN is conducting a study for a new proton-proton collider, called Future Circular Collider (FCC-hh), running at center-of-mass energies of up to 100 TeV in a new 100 km tunnel. The study includes a 90-350 GeV lepton collider (FCC-ee) as well as a lepton-hadron option (FCC-he). In this work, FLUKA Monte Carlo simulation was extensively used to perform a first evaluation of the radiation environment in critical areas for electronics in the FCC-hh tunnel. The model of the tunnel was created based on the original civil engineering studies already performed and further integrated in the existing FLUKA models of the beam line. The radiation levels in critical areas, such as the racks for electronics and cables, power converters, service areas, local tunnel extensions was evaluated.

  8. The practical use of an interactive visualization and planning tool for intervention planning in particle accelerator environments with ionizing radiation

    Science.gov (United States)

    Fabry, Thomas; Blaha, Jan; Vanherpe, Liesbeth; Braesch, Christian; Tabourot, Laurent; Feral, Bruno

    2014-04-01

    A core issue during the planning of a maintenance intervention in a facility with ionizing radiation is the minimization of the integrated equivalent dose contracted by the maintenance workers during the intervention. In this work, we explore the use of a technical-scientific software program facilitating the intervention planning in irradiated environments using sound mathematical concepts. We show how the software can be used in planning future operations using a case studies: the decommissioning of a beam dump for a linear 160 MeV H- accelerator. Interactive visualization of the facilities and radiation levels, as well as tools for interactive trajectory planning are explored, as well as automatic calculation of the expected integrated individual dose contracted during an intervention.

  9. The practical use of an interactive visualization and planning tool for intervention planning in particle accelerator environments with ionizing radiation

    CERN Document Server

    Fabry, Thomas; Vanherpe, Liesbeth; Braesch, Christian; Tabourot, Laurent; Feral, Bruno

    2014-01-01

    A core issue during the planning of a maintenance intervention in a facility with ionizing radiation is the minimization of the integrated equivalent dose contracted by the maintenance workers during the intervention. In this work, we explore the use of a technical-scientific software program facilitating the intervention planning in irradiated environments using sound mathematical concepts. We show how the software can be used in planning future operations using a case studies: the decommissioning of a beam dump for a linear 160 MeV H− accelerator. Interactive visualization of the facilities and radiation levels, as well as tools for interactive trajectory planning are explored, as well as automatic calculation of the expected integrated individual dose contracted during an intervention.

  10. Application of the modified Wheeler cap method for radiation efficiency measurement of balanced electrically small antennas in complex environment

    DEFF Research Database (Denmark)

    Zhang, Jiaying; Pivnenko, Sergey; Breinbjerg, Olav

    2010-01-01

    In this paper, application of a modified Wheeler cap method for the radiation efficiency measurement of balanced electrically small antennas is presented. It is shown that the limitations on the cavity dimension can be overcome and thus measurement in a large cavity is possible. The cavity loss...... is investigated, and a modified radiation efficiency formula that includes the cavity loss is introduced. Moreover, a modification of the technique is proposed that involves the antenna working complex environment inside the Wheeler Cap and thus makes possible measurement of an antenna close to a hand or head...... phantom. The measurement procedures are described and the key features of the technique are discussed. The results of simulations and measurements by the proposed method are presented and compared....

  11. Terrestrial Gamma Radiation Exposure Measurement and Risk Estimates in the Environments of Major Industries In Ota, Nigeria

    Directory of Open Access Journals (Sweden)

    Abodunrin Oluwasayo Peter

    2016-11-01

    Full Text Available When fast estimates are required, the in-situ method is more appropriate as this allows for quick results; preventing further exposure of the public and permitting quick intervention. Measurements of the terrestrial gamma radiation exposure have been carried out in the environments of major industries in Ota using a portable survey meter. The motivation for this study resulted from the uncertainty in the general public opinion on the effect of the presence, and activities of some of these industries in their environment. Measurements were taken twice daily within the vicinity of each industry to determine the dose levels. The mean values obtained range from 0.11 – 1.80 µSv/h. These values are within the results obtained from normal background areas except for site number 10. Annual effective dose values range from 0.25 – 5.21 mSv with a mean value of 1.21 mSv. Routine activities in some of these environments may have contributed significantly to the ambient natural background radiation resulting in high values as obtained in some of these locations. The total risks disparately estimated for cancer and genetic effects resulting from the results obtained range from 0.17 x 10-4 – 3.80 x 10-4 with a mean value of 0.94 x 10-4. These levels are within the range of the average annual risk for accidental death for all industries.

  12. Evaluation of cryogenic insulation materials and composites for use in nuclear radiation environments

    Science.gov (United States)

    Bullock, R. E.

    1972-01-01

    The following subjects are studied: (1) composite materials tests; (2) test of liquid level sensors and fission couples; (3) test of valve-seal materials; (4) boron epoxy composites; (5) radiation analysis of explosive materials and bifuels for RNS applications; and (6) test of thermal insulation.

  13. Star tracker and vision systems performance in a high radiation environment

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Riis, Troels; Betto, Maurizio

    1999-01-01

    A part of the payload of the second Ariane 5 prototype vehicle to be launched by Arianespace, was a small technology demonstration satellite. On October 30th, 1997, this test satellite, dubbed Teamsat, was launched into Geostationary Transfer Orbit and would as such pass the Van Allen radiation b...

  14. Gluon Radiation off Hard Quarks in a Nuclear Environment Opacity Expansion

    CERN Document Server

    Wiedemann, Urs Achim

    2000-01-01

    We study the relation between the Baier-Dokshitzer-Mueller-Peigne-Schiff (BDMPS) and Zakharov formalisms for medium-induced gluon radiation off hard quarks, and the radiation off very few scattering centers. Based on the non-abelian Furry approximation for the motion of hard partons in a spatially extended colour field, we derive a compact diagrammatic and explicitly colour trivial expression for the N-th order term of the kt-differential gluon radiation cross section in an expansion in the opacity of the medium. Resumming this quantity to all orders in opacity, we obtain Zakharov's path-integral expression (supplemented with a regularization prescription). This provides a new proof of the equivalence of the BDMPS and Zakharov formalisms which extends previous arguments to the kt-differential cross section. We give explicit analytical results up to third order in opacity for both the gluon radiation cross section of free incoming and of in-medium produced quarks. The N-th order term in the opacity expansion o...

  15. Influence of nonequilibrium radiation and shape change on aerothermal environment of Jovian entry body

    Science.gov (United States)

    Tiwari, S. N.; Subramanian, S. V.

    1980-01-01

    Radiative transfer equations are derived under nonequilibrium conditions which include multilevel energy transitions. The nonequalibrium results, obtained with and without ablation injection in the shock layer, are found to be greatly influenced by the temperature distribution in the shock layer. In the absence of ablative products, the convective and radiative heating to the entry body are reduced significantly under nonequilibrium conditions. The influence of nonequilibrium is found to be greater at higher entry altitudes. With coupled ablation and carbon phenolic injection, 16 chemical species are used in the ablation layer for radiation absorption. Equilibrium and nonequilibrium results are compared under peak heating conditions. A 45 degree sphere cone, a 35 degree hyperboloid, and a 45 degree ellipsoid were used to study probe shape change. Results indicate that the shock layer flow field and heat transfer to the body are influenced significantly by the probe shape change. The effect of shape change on radiative heating of the afterbodies is found to be considerably larger for the sphere cone and ellipsoid than for the hyperboloid.

  16. THE EFFECT OF SOLAR RADIATION ON AUTOMOBILE ENVIRONMENT THROUGH NATURAL CONVECTION AND MIXED CONVECTION

    Directory of Open Access Journals (Sweden)

    MD. FAISAL KADER

    2012-10-01

    Full Text Available In the present paper, the effect of solar radiation on automobiles has been studied by both experimentally and numerically. The numerical solution is done by an operation friendly and fast CFD code – SC/Tetra with a full scale model of a SM3 car and turbulence is modeled by the standard k-ε equation. Numerical analysis of the three-dimensional model predicts a detailed description of fluid flow and temperature distribution in the passenger compartment during both the natural convection due to the incoming solar radiation and mixed convection due to the flow from defrost nozzle and radiation. It can be seen that solar radiation is an important parameter to raise the compartment temperature above the ambient temperature during summer. During natural convection, the rate of heat transfer is fast at the initial period. In the mixed convection analyses, it is found that the temperature drops down to a comfortable range almost linearly at the initial stage. Experimental investigations are performed to determine the temperature contour on the windshield and the local temperature at a particular point for further validation of the numerical results.

  17. Development of MAAP5.0.3 Dose Model for Radiation Environment Effect Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Mi Ro [KHNP-CRI, Daejeon (Korea, Republic of)

    2015-10-15

    The equipment survivability assessment under the severe accident conditions should be performed. For the environmental conditions such as the pressure and temperature, they can be calculated using MAAP (Modular Accident Analysis Program) code. However, since MAAP itself cannot calculate the radiation DOSE, MAAP5 DOSE model should be developed in order to calculate the DOSE rate during the severe accidents. In this study, we developed the MAAP5 DOSE model for spent fuel pool of OPR1000 type NPP and calculated the DOSE to assess the survivability of the facilities in spent fuel pool and fuel handling region. Until now, there are so many uncertainties in the analysis for radiation effect during the severe accident. However, in terms of the establishment of the severe accident management strategy, quantitative analysis in order to find the general trend for radiation increase during the severe accident is useful. For the radiation environmental effect analysis, the previous studies are mainly focused inside the containment. However, after the Fukushima accident, the severe accident phenomena in the SFP have been the great issues in the nuclear industry including Korea. So, in this study, the dose rate for spent fuel building when the severe accident happens in the SFP is calculated using MAAP5 DOSE. As expected, the dose rate is increased right after the spent fuel is partially uncovered. However, the amount of dose is less significant since the rate of temperature increase is much faster than the rate of dose increase.

  18. Monitoring of radiation in the environment in the Netherlands. Results in 2002

    NARCIS (Netherlands)

    Knetsch GJ; RIZA; RIKZ; KvW; LSO; IMD

    2004-01-01

    The Dutch government is compelled to measure radioactivity in the environment under terms of the Euratom Treaty of 1957. This report presents the results of radioactivity measurements in the Dutch environment in 2002. The measurements were carried out by RIVM, RIZA, RIKZ and Inspectorate for Health

  19. An overview of the radiation environment at the LHC in light of R2E irradiation test activities

    CERN Document Server

    Roeed, K; Spiezia, G; CERN. Geneva. ATS Department

    2011-01-01

    The main objective of this report is to present a brief overview of the radiation environment that can be expected in areas where electronics is installed in the LHC. This covers particle energy spectra in addition to nominal integrated values of the High Energy Hadron (HEH) fluence, relevant for Single Event Effects (SEEs), Total Ionizing Dose (TID), and the 1 MeV neutron equivalent, relevant for displacement damage. The risk of thermal neutrons is considered by introducing the risk factor Rth. This report is presented as part of the R2E project and should create a foundation from which appropriate irradiation test criteria can be evaluated and determined.

  20. An Assessment of the Space Radiation Environment in a Near Equatorial Low Earth Orbit Based on Razaksat-1 Satellite

    CERN Document Server

    Suparta, Wayan

    2015-01-01

    The Malaysian satellite RazakSAT-1 was designed to operate in a near-equatorial orbit (NEqO) and low earth orbit (LEO). However, after one year of operation in 2010, communication to the satellite was lost. This study attempted to identify whether space radiation sources could have caused the communication loss by comparing RazakSAT-1 with two functional satellites. Data on galactic cosmic rays (GCR), trapped protons, trapped electrons, and solar energetic particles (SEPs) obtained from Space Environment Information System (SPENVIS) was analyzed.

  1. Calculations and observations of solar particle enhancements to the radiation environment at aircraft altitudes

    Science.gov (United States)

    Dyer, C. S.; Lei, F.; Clucas, S. N.; Smart, D. F.; Shea, M. A.

    Solar particle events can give greatly enhanced radiation at aircraft altitudes, but are both difficult to predict and to calculate retrospectively. This enhanced radiation can give significant dose to aircrew and greatly increase the rate of single event effects in avionics. Validation of calculations is required but only very few events have been measured in flight. The CREAM detector on Concorde detected the event of 29 September 1989 and also four periods of enhancement during the events of 19-24 October 1989. Instantaneous rates were enhanced by up to a factor ten compared with quiet-time cosmic rays, while flight-averages were enhanced by up to a factor six. Calculations are described for increases in radiation at aircraft altitudes using solar particle spectra in conjunction with Monte Carlo radiation transport codes. In order to obtain solar particle spectra with sufficient accuracy over the required energy range it is necessary to combine space data with measurements from a wide range of geomagnetically dispersed, ground-level neutron monitors. Such spectra have been obtained for 29 September 1989 and 24 October 1989 and these are used to calculate enhancements that are compared with the data from CREAM on Concorde. The effect of cut-off rigidity suppression by geomagnetic activity is shown to be significant. For the largest event on record on 23 February 1956, there are no space data but there are data from a number of ground-level cosmic-ray detectors. Predictions for all events show very steep dependencies on both latitude and altitude. At high latitude and altitude (17 km) calculated increases with respect to cosmic rays are a factor 70 and 500 respectively for 29 September 1989 and 23 February 1956. The levels of radiation for high latitude, subsonic routes are calculated, using London to Los Angeles as an example, and can exceed 1 mSv, which is significantly higher than for Concorde routes from Europe to New York. The sensitivity of the calculations

  2. Modeling Electrostatic Fields Generated by Internal Charging of Materials in Space Radiation Environments

    Science.gov (United States)

    Minow, Joseph I.

    2011-01-01

    Internal charging is a risk to spacecraft in energetic electron environments. DICTAT, NU MIT computational codes are the most widely used engineering tools for evaluating internal charging of insulator materials exposed to these environments. Engineering tools are designed for rapid evaluation of ESD threats, but there is a need for more physics based models for investigating the science of materials interactions with energetic electron environments. Current tools are limited by the physics included in the models and ease of user implementation .... additional development work is needed to improve models.

  3. Radiation Hardened High Speed Fiber Optic Transceivers for Extreme Environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This program develops fiber optic transceivers that offer wide bandwidth (1 Mbps to 10 Gbps) and operate in space environments targeted by NASA for robotic...

  4. Radiation Hardened High Speed Fiber Optic Transceivers for Extreme Environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the development of transceiver offering wide bandwidth (1 Mbps to 10 Gbps) that operates in space environments targeted by NASA for robotic exploration....

  5. Research of the radiation tolerance in space environment of general electronic devices

    OpenAIRE

    Maeda, Takahiro; Kakimi, Yukitaka; Akashi, Kenji; Oshima, Takeshi; Onoda, Shinobu

    2013-01-01

    In small satellite development, general electronic (COTS) devices are needed to use due to some severe restrictions of resource for installed components. For this reason, it is important to keep reliability for using COTS devices in small satellite development. Therefore, in order to ensure reliability for small satellite, our company has evaluated COTS devices mainly for tolerance of single event at Japan Atomic Energy Agency (JAEA) Takasaki Advanced Radiation Research Institute from fiscal ...

  6. Monitoring of radiation in the environment in the Netherlands. Results in 2001

    CERN Document Server

    Knetsch, G J

    2002-01-01

    This report presents the results of radioactivity measurements in the Dutch environment in 2001. The measurements were carried out by RIVM, RIZA, RIKZ and Inspectorate for Health Protection and Veterinary Public Health. Radioactivity measurements were carried out on airborne particles, deposition, surface water, seawater, drinking water and food (honey, powdered milk, game, poultry, blueberry and chanterelle). Results for ambient dose equivalent rates were obtained from the National Radioactivity Monitoring Network. The levels of radioactivity in the Dutch environment were not elevated in 2001

  7. Monitoring of radiation in the environment in the Netherlands. Results in 2001

    Energy Technology Data Exchange (ETDEWEB)

    Knetsch, G.J. (ed.)

    2002-07-01

    This report presents the results of radioactivity measurements in the Dutch environment in 2001. The measurements were carried out by RIVM, RIZA, RIKZ and Inspectorate for Health Protection and Veterinary Public Health. Radioactivity measurements were carried out on airborne particles, deposition, surface water, seawater, drinking water and food (honey, powdered milk, game, poultry, blueberry and chanterelle). Results for ambient dose equivalent rates were obtained from the National Radioactivity Monitoring Network. The levels of radioactivity in the Dutch environment were not elevated in 2001.

  8. A study on the radiation and environment safety -Development of technology for biological dosimetry-

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kang Suk; Kim, Kook Chan; Kim, In Kyoo; Kim, Jin Kyoo; Chun Kee Jung; Park, Hyo Kook; Kim, Sang Bok; Park Sun Yung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-07-01

    Adult rats were treated a single, whole body exposure to a dose of 0.1, 0.5, 1.0, 2.0, 3.0 Gy. The animals were sacrificed 6, 24, 48, 72, 96 hours following exposure. The amount of serum acute phase proteins(haptoglobin, ceruloplasmin, C-reactive protein, alpha-1 antitrypsin, alpha-1 acid glycoprotein, transferrin) were measured by competitive ELISA. In the 0.1 Gy irradiated rats, serum haptoglobin, C-reactive protein and alpha-1 antitrypsin were 400% higher and serum transferrin was 50% lower as compared to controls, 96 hours after irradiation. Ceruloplasmin increased by 400%, 24 hours after irradiation, but 96 hours after irradiation, the concentration of this protein in rat returned to normal level. On the other hand, no changes were observed in the case of alpha-1 acid glycoprotein. In the group of the 3.0 Gy irradiated rats, transferrin increased by 200%, 96 hours after irradiation. These biochemical responses to radiation did not show dose-dependent relation, but the sensitivity of the indicators was high enough to detect absorbed dose of 0.1 Gy. The above results can be applied to the measurements of acute phase reactants in human serum for the assessment of exposure doses in radiation workers and patients under radiation therapy. 39 figs, 72 refs. (Author).

  9. Web-based description of the space radiation environment using the Bethe-Bloch model

    CERN Document Server

    Cazzola, Emanuele; Lapenta, Giovanni

    2015-01-01

    Space weather is a rapidly growing area not only in scientific and engineering applications but also in physics education and in the interest of the public. We focus especially on space radiation and its impact on space exploration. The topic is highly interdisciplinary bringing together fundamental concepts of nuclear physics with aspects of radiation protection and space science. We present a new approach to presenting the topic by developing a web-based tool that combines some of the fundamental concepts from these two fields in a single tool that can be developed in the context of advanced secondary or undergraduate university education. We present DREADCode, an outreach or teaching tool to asses rapidly the current conditions of the radiation field in space. DREADCode uses the available data feeds from a number of ongoing space missions to produce a first order approximation of the dose an astronaut would receive during a mission of exploration in deep space. DREADcode is based on a intuitive GUI interfa...

  10. Radiation resistance of lactobacilli isolated from radurized meat relative to growth and environment.

    Science.gov (United States)

    Hastings, J W; Holzapfel, W H; Niemand, J G

    1986-10-01

    Of 113 lactobacilli isolated from radurized (5 kGy) minced meat, 7 Lactobacillus sake strains, 1 L. curvatus strain, and 1 L. farciminis strain were used for radiation resistance studies in a semisynthetic substrate (i.e., modified MRS broth). Five reference Lactobacillus spp., one Staphylococcus aureus strain, and one Salmonella typhimurium strain were used for comparative purposes. All L. sake isolates exhibited the phenomenon of being more resistant to gamma-irradiation in the exponential (log) phase than in the stationary phase of their growth cycles by a factor of 28%. Four references strains also exhibited this phenomenon, with L. sake (DSM 20017) showing a 68% increase in resistance in the log phase over the stationary phase. This phenomenon was not common to all bacteria tested and is not common to all strains with high radiation resistance. Four L. sake isolates and three reference strains were used in radiation sensitivity testing in a natural food system (i.e., meat). The bacteria were irradiated in minced meat and packaged under four different conditions (air, vacuum, CO2, and N2). Organisms exhibited the highest death rate (lowest D10 values [doses required to reduce the logarithm of the bacterial population by 1] ) under CO2 packaging conditions, but resistance to irradiation was increased under N2. The D10 values of the isolates were generally greater than those of the reference strains. The D10 values were also higher (approximately two times) in meat than in semisynthetic growth medium.

  11. Measurement and Analysis of Radio-frequency Radiation Exposure Level from Different Mobile Base Transceiver Stations in Ajaokuta and Environs, Nigeria

    CERN Document Server

    Ushie, P O; Bolaji, Ayinmode; Osahun, O D

    2013-01-01

    We present the result of a preliminary assessment of radio-frequency radiation exposure from selected mobile base stations in Ajaokuta environs. The Power density of RF radiation within a radial distance of 125m was measured. Although values fluctuated due to the influence of other factors, including wave interference from other electromagnetic sources around reference base stations, we show from analysis that radiation exposure level is below the standard limit (4.5W/sqm for 900MHz and 9W/sqm for 18000MHz) set by the International Commission on Non-ionizing Radiation Protection (ICNIRP) and other regulatory agencies.

  12. Preliminary Assessment of Potential Habitat Composites' Durability when Exposed to a Long-Term Radiation Environment and Micrometeoroid Impacts

    Science.gov (United States)

    Rojdev, Kristina; Graves, Russell; Golden, John; Atwell, William; O'Rouke, Mary Jane; Hill, Charles; Alred, John

    2011-01-01

    NASA's exploration goals include extending human presence beyond low earth orbit (LEO). As a result, habitation for crew is a critical requirement for meeting this goal. However, habitats are very large structures that contain a multitude of subsystems to sustain human life over long-durations in space, and one of the key challenges has been keeping weight to a minimum in order to reduce costs. Thus, light-weight and multifunctional structural materials are of great interest for habitation. NASA has started studying polymeric composite materials as potential lightweight and multifunctional structural materials for use in long-duration spaceflight. However, little is known about the survivability of these materials when exposed to the space environment outside of LEO for long durations. Thus, a study has been undertaken to investigate the durability of composite materials when exposed to long-duration radiation. Furthermore, as an addition to the primary study, a secondary preliminary investigation has been started on the micrometeoroid and orbital debris (MMOD) susceptibility of these materials after radiation exposure. The combined effects of radiation and MMOD impacts are the focus of this paper.

  13. Preliminary Results for the Radiation Environment Observed by RD3-B3 Radiometerdosimeter Inside Bion-M # 1 Spacecraft

    Science.gov (United States)

    Dachev, Tsvetan; Tomov, Borislav; Matviichuk, Yury; Dimitrov, Plamen; Bankov, Nikolay; Petrov, Vladisloav; Shurshakov, Viacheslav; Ivanova, Olga; Häder, Donat-Peter; Lebert, Michael; Schuster, Martin; Reitz, Günter; Horneck, Gerda; Ploc, Ondrej

    2013-12-01

    Space radiation has been monitored using the P#xd0bb;3-킑3 (further is used the Latin transcription RD3-B3) spectrometer-dosimeter on board a recent space flight on the Russian recoverable satellite 킑킍OH-M No.1 (further is used the Latin transcription BIONM No. 1). The instrument was mounted inside of the satellite in pressurized volume together with biological objects and samples. RD3-B3 instrument is a battery operated version of the spare model of the R3D-B3 instrument developed and built for the ESA BIOPAN-6 facility on Foton M3 satellite flown in September 2007. Cosmic ionizing radiation has been monitored and separated in 256 deposited energy spectra, which were further used for determination of the absorbed dose rate and flux. The report summarizes the first results for the Earth radiation environment at the altitude (253-585 km) of the BION-M No.1 spacecraft.

  14. A Monte Carlo-based radiation safety assessment for astronauts in an environment with confined magnetic field shielding.

    Science.gov (United States)

    Geng, Changran; Tang, Xiaobin; Gong, Chunhui; Guan, Fada; Johns, Jesse; Shu, Diyun; Chen, Da

    2015-12-01

    The active shielding technique has great potential for radiation protection in space exploration because it has the advantage of a significant mass saving compared with the passive shielding technique. This paper demonstrates a Monte Carlo-based approach to evaluating the shielding effectiveness of the active shielding technique using confined magnetic fields (CMFs). The International Commission on Radiological Protection reference anthropomorphic phantom, as well as the toroidal CMF, was modeled using the Monte Carlo toolkit Geant4. The penetrating primary particle fluence, organ-specific dose equivalent, and male effective dose were calculated for particles in galactic cosmic radiation (GCR) and solar particle events (SPEs). Results show that the SPE protons can be easily shielded against, even almost completely deflected, by the toroidal magnetic field. GCR particles can also be more effectively shielded against by increasing the magnetic field strength. Our results also show that the introduction of a structural Al wall in the CMF did not provide additional shielding for GCR; in fact it can weaken the total shielding effect of the CMF. This study demonstrated the feasibility of accurately determining the radiation field inside the environment and evaluating the organ dose equivalents for astronauts under active shielding using the CMF.

  15. Design of a MGy radiation tolerant resolver-to-digital convertor IC for remotely operated maintenance in harsh environments

    Energy Technology Data Exchange (ETDEWEB)

    Leroux, Paul, E-mail: paul.leroux@kuleuven.be [KU Leuven, Dept. of Electrical Engineering (ESAT), AdvISe, Kleinhoefstraat 4, 2440 Geel (Belgium); Van Koeckhoven, Wesley; Verbeeck, Jens [KU Leuven, Dept. of Electrical Engineering (ESAT), AdvISe, Kleinhoefstraat 4, 2440 Geel (Belgium); Van Uffelen, Marco; Esqué, Salvador; Ranz, Roberto; Damiani, Carlo [Fusion for Energy, Torres Diagonal Litoral B3, Josep Pla 2, 08019 Barcelona (Spain); Hamilton, David [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul-lez-Durance (France)

    2014-10-15

    During future ITER maintenance operations, sensors and their embarked electronics will be exposed to a hostile and radioactive environment. This paper presents the design of a MGy radiation tolerant 16 bit resolver-to-digital converter (RDC) in 130 nm CMOS technology. The RDC features a Type II digital tracking loop, able to track resolvers with speeds up to 300 rps, and excitation frequencies up to 4 kHz. The RDC uses two integrated ΔΣ-analog-to-digital converters (ADCs) to digitize the resolver outputs. The 16 bit, 10 kHz ADCs utilize a correlated double sampling technique to remove radiation induced offset and 1/f-noise. The front-end features a static angular resolution of 16 bits (4.2 arcsec{sub rms}) and a resolution of 10 bits (6 arcmin{sub rms}) at a rotor speed of 100 rps. The circuit has a simulated radiation tolerance exceeding 1 MGy. It has the ability to operate under temperatures up to 125 °C, and to allow multiplexing with signals from other conventional sensors for compact, robust read-out architectures.

  16. Adaptation to high CO2 concentration in an optimal environment: radiation capture, canopy quantum yield and carbon use efficiency

    Science.gov (United States)

    Monje, O.; Bugbee, B.

    1998-01-01

    The effect of elevated [CO2] on wheat (Triticum aestivum L. Veery 10) productivity was examined by analysing radiation capture, canopy quantum yield, canopy carbon use efficiency, harvest index and daily C gain. Canopies were grown at either 330 or 1200 micromoles mol-1 [CO2] in controlled environments, where root and shoot C fluxes were monitored continuously from emergence to harvest. A rapidly circulating hydroponic solution supplied nutrients, water and root zone oxygen. At harvest, dry mass predicted from gas exchange data was 102.8 +/- 4.7% of the observed dry mass in six trials. Neither radiation capture efficiency nor carbon use efficiency were affected by elevated [CO2], but yield increased by 13% due to a sustained increase in canopy quantum yield. CO2 enrichment increased root mass, tiller number and seed mass. Harvest index and chlorophyll concentration were unchanged, but CO2 enrichment increased average life cycle net photosynthesis (13%, P < 0.05) and root respiration (24%, P < 0.05). These data indicate that plant communities adapt to CO2 enrichment through changes in C allocation. Elevated [CO2] increases sink strength in optimal environments, resulting in sustained increases in photosynthetic capacity, canopy quantum yield and daily C gain throughout the life cycle.

  17. The low Earth orbit radiation environment and its impact on the prompt background of hard x-ray focusing telescopes

    Science.gov (United States)

    Fioretti, V.; Bulgarelli, A.; Malaguti, G.; Bianchin, V.; Trifoglio, M.; Gianotti, F.

    2012-07-01

    The background minimization is a science-driven necessity in order to reach deep sensitivity levels in the hard X-ray band, one of the key scientific requirements for hard X-ray telescopes (e.g. NuSTAR, ASTRO-H). It requires a careful modeling of the radiation environment and new concepts of shielding systems. We exploit the Bologna Geant4 Multi-Mission Simulator (BoGEMMS) features to evaluate the impact of the Low Earth Orbit (LEO) radiation environment on the prompt background level for a hybrid Si/CdTe soft and hard X-ray detection assembly and a combined active and passive shielding system. For each class of particles, the spectral distribution of the background flux is simulated, exploring the effect of different materials (plastic vs inorganic active scintillator) and configurations (passive absorbers enclosing or surrounded by the active shielding) on the background count rate. While protons are efficiently removed by the active shielding, an external passive shielding causes the albedo electrons and positrons to be the primary source of background. Albedo neutrons are instead weakly interactive with the active shielding, and they cause an intense background level below 10 keV via elastic scattering. The best shielding configuration in terms of background and active shielding count rates is given by an inorganic scintillator placed inside the passive layers, with the addition of passive material to absorb the intense fluorescence lines of the active shielding and avoid escape peaks on the CdTe detector.

  18. Adaptation to high CO2 concentration in an optimal environment: radiation capture, canopy quantum yield and carbon use efficiency

    Science.gov (United States)

    Monje, O.; Bugbee, B.

    1998-01-01

    The effect of elevated [CO2] on wheat (Triticum aestivum L. Veery 10) productivity was examined by analysing radiation capture, canopy quantum yield, canopy carbon use efficiency, harvest index and daily C gain. Canopies were grown at either 330 or 1200 micromoles mol-1 [CO2] in controlled environments, where root and shoot C fluxes were monitored continuously from emergence to harvest. A rapidly circulating hydroponic solution supplied nutrients, water and root zone oxygen. At harvest, dry mass predicted from gas exchange data was 102.8 +/- 4.7% of the observed dry mass in six trials. Neither radiation capture efficiency nor carbon use efficiency were affected by elevated [CO2], but yield increased by 13% due to a sustained increase in canopy quantum yield. CO2 enrichment increased root mass, tiller number and seed mass. Harvest index and chlorophyll concentration were unchanged, but CO2 enrichment increased average life cycle net photosynthesis (13%, P CO2 enrichment through changes in C allocation. Elevated [CO2] increases sink strength in optimal environments, resulting in sustained increases in photosynthetic capacity, canopy quantum yield and daily C gain throughout the life cycle.

  19. Adaptation to high CO2 concentration in an optimal environment: radiation capture, canopy quantum yield and carbon use efficiency

    Science.gov (United States)

    Monje, O.; Bugbee, B.

    1998-01-01

    The effect of elevated [CO2] on wheat (Triticum aestivum L. Veery 10) productivity was examined by analysing radiation capture, canopy quantum yield, canopy carbon use efficiency, harvest index and daily C gain. Canopies were grown at either 330 or 1200 micromoles mol-1 [CO2] in controlled environments, where root and shoot C fluxes were monitored continuously from emergence to harvest. A rapidly circulating hydroponic solution supplied nutrients, water and root zone oxygen. At harvest, dry mass predicted from gas exchange data was 102.8 +/- 4.7% of the observed dry mass in six trials. Neither radiation capture efficiency nor carbon use efficiency were affected by elevated [CO2], but yield increased by 13% due to a sustained increase in canopy quantum yield. CO2 enrichment increased root mass, tiller number and seed mass. Harvest index and chlorophyll concentration were unchanged, but CO2 enrichment increased average life cycle net photosynthesis (13%, P CO2 enrichment through changes in C allocation. Elevated [CO2] increases sink strength in optimal environments, resulting in sustained increases in photosynthetic capacity, canopy quantum yield and daily C gain throughout the life cycle.

  20. Radiation Protection of the Public and the Environment. Overcoming Environmental Monitoring Inertia

    Energy Technology Data Exchange (ETDEWEB)

    Parker, T.G.; Desmond, J.A. [British Nuclear Group Sellafield Ltd. (United Kingdom); Stevens, A.K. [Westlakes Scientific Consulting (United Kingdom)

    2006-07-01

    The first nuclear reactors at Sellafield went critical in 1951 and fuel reprocessing commenced shortly afterwards. As the nuclear programme expanded, reprocessing increased and there was an associated increase in discharges to the environment. An initial environmental monitoring programme was formulated on the basis of research and assessment of the likely behaviour of radionuclides. In addition to the routine process sources there were also incidents that gave rise to acute releases of radioactivity to the environment. Of key significance were: the Windscale fire, 1957; short-cooled fuel reprocessing, 1981; and discharge of contaminated solvent, 1983. All of these incidents added to the requirements for environments for environmental monitoring. The monitoring programme has evolved over a period of more than 50 years. (N.C.)

  1. Personal Active Dosimeter for Space: the Light Observer for Radiation Environment (LORE) project

    Science.gov (United States)

    Narici, Livio

    Long permanence in space outside the protections of the Earth magnetic shield and atmosphere (during long journeys, and on the Moon or/and Mars) requires a careful monitoring of absorbed doses by each astronaut. This is of paramount importance for transient and cumulative effects mostly due to Solar Particle Events. Alarming features and the possibility of monitoring absorbed dose also discriminating the kind of incoming radiation will be needed. Stemming from our large experience in detector building, in modelling, in designing of the supporting electronic, from our payloads flown on satellites, MIR Station and ISS (Nina, Mita, SilEye, SilEye2, Alteino, Pamela, ALTEA) we are developping a personal active dosimeter with alarming and wireless features. The goal is a small object able to measure charged and neutral ionizing radiation (the possibility to insert a miniaturized gamma detector will be investigated) The device will feature portability (cigarette-box dimensions, rechargeable batteries), sensitivity to ions (H to above Fe), to hard X-rays, and possibly to gamma with the ability to detect and count neutrons. Flash memories should contain pre loaded tables and the real Time code to perform the real time operations and risk thresholds so to activate an alarm if/when needed. Whenever in range, the device will connect wirelessly to the main computer and send there the raw and pre-analyzed data for a complete monitoring and possible more sophisticated analyses. The two major novelties and challenges in this project are the miniaturization of the device, including the firmware, and the definition of the transfer function and of its uncertainties, linking measured data with real flux data. This will require the proper balancing among size, radiation discrimination ability and uncertainty minimization.

  2. The close environments of accreting massive black holes are shaped by radiative feedback

    Science.gov (United States)

    Ricci, Claudio; Trakhtenbrot, Benny; Koss, Michael J.; Ueda, Yoshihiro; Schawinski, Kevin; Oh, Kyuseok; Lamperti, Isabella; Mushotzky, Richard; Treister, Ezequiel; Ho, Luis C.; Weigel, Anna; Bauer, Franz E.; Paltani, Stephane; Fabian, Andrew C.; Xie, Yanxia; Gehrels, Neil

    2017-09-01

    The majority of the accreting supermassive black holes in the Universe are obscured by large columns of gas and dust. The location and evolution of this obscuring material have been the subject of intense research in the past decades, and are still debated. A decrease in the covering factor of the circumnuclear material with increasing accretion rates has been found by studies across the electromagnetic spectrum. The origin of this trend may be driven by the increase in the inner radius of the obscuring material with incident luminosity, which arises from the sublimation of dust; by the gravitational potential of the black hole; by radiative feedback; or by the interplay between outflows and inflows. However, the lack of a large, unbiased and complete sample of accreting black holes, with reliable information on gas column density, luminosity and mass, has left the main physical mechanism that regulates obscuration unclear. Here we report a systematic multi-wavelength survey of hard-X-ray-selected black holes that reveals that radiative feedback on dusty gas is the main physical mechanism that regulates the distribution of the circumnuclear material. Our results imply that the bulk of the obscuring dust and gas is located within a few to tens of parsecs of the accreting supermassive black hole (within the sphere of influence of the black hole), and that it can be swept away even at low radiative output rates. The main physical driver of the differences between obscured and unobscured accreting black holes is therefore their mass-normalized accretion rate.

  3. Progress in radiation processing vol 1; food/environment/elastomers and polymers

    Energy Technology Data Exchange (ETDEWEB)

    Nablo, S.V. (ed.)

    1984-10-01

    This paper reports on the planning process for the conference on Radiation Processing. The final program was made up of six sessions on food applications, four on elastomers and polymers, two on environmental applications with eighteen additional sessions over the five day conference period. The emerging industrial applications of electron processing were highlighted in those sessions on graphics, magnetic media and semiconductors and there was some difficulty presenting a materials handling session due to the continuing reluctance of the equipment manufacturers to discuss proprietary details of web, sheet, formed product and wire handling machinery.

  4. CMOS pixel sensors on high resistive substrate for high-rate, high-radiation environments

    Science.gov (United States)

    Hirono, Toko; Barbero, Marlon; Breugnon, Patrick; Godiot, Stephanie; Gonella, Laura; Hemperek, Tomasz; Hügging, Fabian; Krüger, Hans; Liu, Jian; Pangaud, Patrick; Peric, Ivan; Pohl, David-Leon; Rozanov, Alexandre; Rymaszewski, Piotr; Wang, Anqing; Wermes, Norbert

    2016-09-01

    A depleted CMOS active pixel sensor (DMAPS) has been developed on a substrate with high resistivity in a high voltage process. High radiation tolerance and high time resolution can be expected because of the charge collection by drift. A prototype of DMAPS was fabricated in a 150 nm process by LFoundry. Two variants of the pixel layout were tested, and the measured depletion depths of the variants are 166 μm and 80 μm. We report the results obtained with the prototype fabricated in this technology.

  5. A nonventing cooling system for space environment extravehicular activity, using radiation and regenerable thermal storage

    Science.gov (United States)

    Bayes, Stephen A.; Trevino, Luis A.; Dinsmore, Craig E.

    1988-01-01

    This paper outlines the selection, design, and testing of a prototype nonventing regenerable astronaut cooling system for extravehicular activity space suit applications, for mission durations of four hours or greater. The selected system consists of the following key elements: a radiator assembly which serves as the exterior shell of the portable life support subsystem backpack; a layer of phase change thermal storage material, n-hexadecane paraffin, which acts as a regenerable thermal capacitor; a thermoelectric heat pump; and an automatic temperature control system. The capability for regeneration of thermal storage capacity with and without the aid of electric power is provided.

  6. CMOS pixel sensors on high resistive substrate for high-rate, high-radiation environments

    Energy Technology Data Exchange (ETDEWEB)

    Hirono, Toko, E-mail: thirono@uni-bonn.de [Physikalisches Institute der Universität Bonn, Bonn (Germany); Barbero, Marlon; Breugnon, Patrick; Godiot, Stephanie [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Gonella, Laura; Hemperek, Tomasz; Hügging, Fabian; Krüger, Hans [Physikalisches Institute der Universität Bonn, Bonn (Germany); Liu, Jian; Pangaud, Patrick [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Peric, Ivan [IPE, Karlsruher Institut für Technologie, Karlsruhe (Germany); Pohl, David-Leon [Physikalisches Institute der Universität Bonn, Bonn (Germany); Rozanov, Alexandre [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Rymaszewski, Piotr [Physikalisches Institute der Universität Bonn, Bonn (Germany); Wang, Anqing [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Wermes, Norbert [Physikalisches Institute der Universität Bonn, Bonn (Germany)

    2016-09-21

    A depleted CMOS active pixel sensor (DMAPS) has been developed on a substrate with high resistivity in a high voltage process. High radiation tolerance and high time resolution can be expected because of the charge collection by drift. A prototype of DMAPS was fabricated in a 150 nm process by LFoundry. Two variants of the pixel layout were tested, and the measured depletion depths of the variants are 166 μm and 80 μm. We report the results obtained with the prototype fabricated in this technology.

  7. Monitoring of radiation in the environment in the Netherlands. Results in 2000

    CERN Document Server

    Knetsch, G J

    2002-01-01

    This report presents the results of radioactivity measurements in the environment in the Netherlands carried out by RIVM, RIZA, RIKZ and Inspectorate for Health Protection and Veterinary Public Health in 2000. Measurements of radioactivity have been carried out in airborne particulates, deposition, surface water, seawater, drinking water and food (honey, game, blueberry and mushrooms). Results for ambient dose equivalent rates have been obtained from the National Radioactivity Monitoring Network. No measurements were done in milk. In 2000 no elevated levels of radioactivity were found in the Dutch environment

  8. Monitoring of radiation in the environment in the Netherlands. Results in 2000

    Energy Technology Data Exchange (ETDEWEB)

    Knetsch, G.J. (ed.)

    2002-07-01

    This report presents the results of radioactivity measurements in the environment in the Netherlands carried out by RIVM, RIZA, RIKZ and Inspectorate for Health Protection and Veterinary Public Health in 2000. Measurements of radioactivity have been carried out in airborne particulates, deposition, surface water, seawater, drinking water and food (honey, game, blueberry and mushrooms). Results for ambient dose equivalent rates have been obtained from the National Radioactivity Monitoring Network. No measurements were done in milk. In 2000 no elevated levels of radioactivity were found in the Dutch environment.

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

    Science.gov (United States)

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

    2012-07-01

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

  10. Recent advances in stimulated radiation studies during radiowave heating the near earth space environment

    Science.gov (United States)

    Scales, W. A.

    2016-02-01

    Investigation of stimulated radiation, commonly known as stimulated electromagnetic emissions (SEE), produced by the interaction of high-power, high-frequency HF radiowaves with the ionospheric plasma has been a vibrant area of research since the early 1980s. Substantial diagnostic information about ionospheric plasma characteristics, dynamics, and turbulence can be obtained from the frequency spectrum of the stimulated radiation. During the past several decades, so-called wideband SEE which exists in a frequency band of ±100 kHz or so of the transmit wave frequency (which is several MHz) has been investigated relatively thoroughly. Recent upgrades both in transmitter power and diagnostic receiver frequency sensitivity at major ionosphere interaction facilities in Alaska and Norway have allowed new breakthroughs in the ability to study a plethora of processes associated with the ionospheric plasma during these experiments. A primary advance is in observations of so-called narrowband SEE (NSEE) which exists roughly within ±1 kHz of the transmit wave frequency. An overview of several important new results associated with NSEE are discussed as well as implications to new diagnostics of space plasma physics occurring during ionospheric interaction experiments.

  11. Monitoring of radiation in the environment in the Netherlands. Results in 2001

    NARCIS (Netherlands)

    Knetsch GJ; RIZA; RIKZ; LSO

    2003-01-01

    This report presents the results of radioactivity measurements in the Dutch environment in 2001. The measurements were carried out by RIVM, RIZA, RIKZ and Inspectorate for Health Protection and Veterinary Public Health. Radioactivity measurements were carried out on airborne particles, deposition,

  12. Monitoring of radiation in the environment in the Netherlands. Results in 2000

    NARCIS (Netherlands)

    Knetsch GJ; LSO; RIZA; RIKZ; Keuringsdienst van Waren

    2002-01-01

    This report presents the results of radioactivity measurements in the environment in the Netherlands carried out by RIVM, RIZA, RIKZ and Inspectorate for Health Protection and Veterinary Public Health in 2000. Measurements of radioactivity have been carried out in airborne particulates, deposition,

  13. Monitoring of Radiation in the Environment. Results in the Netherlands in 1998

    NARCIS (Netherlands)

    Jacobs JEM; RIZA; RIKZ; Keuringsdienst van Waren; LSO

    2000-01-01

    This report presents the results of radioactivity measurements in the environment in the Netherlands carried out by four organisations in 1998. The yearly averaged gross alfa- and gross beta-activity concentrations in air dust in Bilthoven were 0.0812 and 0.398 mBq4m-3, respectively. The yearly

  14. Impact of harsh radiation on metal-overhang equipped sensors in the LHC environment

    CERN Document Server

    Chatterji, S; Bhardwaj, A; Namrata, S; Srivastava-Ajay, K; Kumar, A; Jha, Manoj Kumar; Shivpuri, R K

    2004-01-01

    The utility of silicon microstrip detectors in future high luminosity colliders, like LHC requires some serious issues concerning radiation hardness to be carefully considered. The performance of metal- overhang (MO) equipped Si micro-strip sensors has been studied after irradiation for the preshower detector to be used in CMS experiment at LHC, CERN. The parameterization of these effects has been performed using Hamburg model to simulate the operation scenario of MO equipped sensors over 10 years of LHC operation. The utility of overhanging metal extension as junction termination technique after type-inversion has been explored for the first time in this work Several interesting results like a shift in the optimal oxide thickness in MO equipped structures after irradiation have been reported. It has been found that the breakdown performance of the device actually improves after irradiation due to the beneficial effect of type-inversion. Dielectric and semi-insulator passivated MO equipped structures have bee...

  15. Optimising the neutron environment of Radiation Portal Monitors: a computational optimisation study

    CERN Document Server

    Gilbert, Mark R; Packer, Lee W

    2015-01-01

    Efficient and reliable detection of radiological or nuclear threats is a crucial part of national and international efforts to prevent terrorist activities. Radiation Portal Monitors (RPMs), which are deployed worldwide, are intended to interdict smuggled fissile material by detecting emissions of neutrons and gamma rays. However, considering the range and variety of threat sources, vehicular and shielding scenarios, and that only a small signature is present, it is important that the design of the RPMs allows these signatures to be accurately differentiated from the environmental background. Using Monte-Carlo neutron-transport simulations of a model helium-3 detector system we have conducted a parameter study to identify the optimum combination of detector shielding and collimation that maximises the sensitivity of RPMs. These structures, which could be simply and cost-effectively added to existing RPMs, can improve the detector response by more than a factor of two relative to an unmodified, bare design. Fu...

  16. Ozone depletion and solar ultraviolet radiation: ocular effects, a United nations environment programme perspective.

    Science.gov (United States)

    Cullen, Anthony P

    2011-07-01

    To describe he role played by the United Nations Environmental Effects Panel with respect to the ocular effects of stratospheric ozone depletion and present the essence of the Health Chapter of the 2010 Assessment. A consideration of solar ultraviolet radiation (UVR) at the Earth's surface as it is affected by atmospheric changes and how these influence sunlight-related eye diseases. A review of the current Assessment with emphasis on pterygium, cataract, ocular melanoma, and age-related macular degeneration. Although the ozone layer is projected to recover slowly in the coming decades, continuing vigilance is required regarding exposure to the sun. Evidence implicating solar UVR, especially UVB, in every tissue of the eye continues to be amassed. The need for ocular UV protection existed before the discovery of the depletion of the ozone layer and will continue even when the layer fully recovers in approximately 2100.

  17. Applicability of a vibration sensor based on the optical fiber Bragg grating in radiation environment

    CERN Document Server

    Fujita, K; Nakazawa, M; Takahashi, H

    2003-01-01

    Fiber Bragg grating (FBG) is a kind of an optical device developing rapidly in these years and it has various excellent characteristics as a sensor. To investigate applicability of FBG as vibration sensor to nuclear plants, measurement systems were developed and tested. As a result, the FBGs could detect vibration even in gamma-ray environment. Moreover, vibration of a component around a cooling system at the YAYOI reactor could be detected successfully with FBG based sensors.

  18. AE9/AP9/SPM Radiation Environment Model: User’s Guide

    Science.gov (United States)

    2014-02-18

    of this document, and [ Seltzer , 1994]. The values in the ‘Shield Depths’ list may be displayed in units of ‘g/cm2’, ‘mm’ or ‘mils’. Using the drop...Energetic Particle and Space Plasma Environment,” Space Science Reviews, [http://dx.doi.org/10.1007/s11214-013-9964-y], March 2013. Seltzer , Stephen

  19. Death of an Arctic Mixed Phase Cloud: How Changes in the Arctic Environment Influence Cloud Properties and Cloud Radiative Feedbacks

    Science.gov (United States)

    Roesler, E. L.; Posselt, D. J.

    2012-12-01

    Arctic mixed phase stratocumulus clouds exert an important influence on the radiative budget over the Arctic ocean and sea ice. Field programs and numerical experiments have shown the properties of these clouds to be sensitive to changes in the surface properties, thermodynamic environment, and aerosols. While it is clear that Arctic mixed-phase clouds respond to changes in the Arctic environment, uncertainty remains as to how climate warming will affect the cloud micro- and macrophysical properties. This is in no small part due to the fact that there are nonlinear interactions between changes in atmospheric and surface properties and changes in cloud characteristics. In this study, large-eddy simulations are performed of an arctic mixed phase cloud observed during the Indirect and Semi-Direct Aerosol Campaign. A parameter-space-filling uncertainty quantification technique is used to rigorously explore how simulated arctic mixed phase clouds respond to changes in the properties of the environment. Specifically, the cloud ice and aerosol concentration, surface sensible and latent heat fluxes, and large scale temperature, water vapor, and vertical motion are systematically changed, and the properties of the resulting clouds are examined. It is found that Arctic mixed phase clouds exhibit four characteristic behaviors: stability, growth, decay, and dissipation. Sets of environmental and surface properties that lead to the emergence of each type of behavior are presented, and the implications for the response of Arctic clouds to changes in climate are explored.

  20. Index of thermal stress for cows (ITSC) under high solar radiation in tropical environments.

    Science.gov (United States)

    Da Silva, Roberto Gomes; Maia, Alex Sandro C; de Macedo Costa, Leonardo Lelis

    2015-05-01

    This paper presents a new thermal stress index for dairy cows in inter-tropical regions, with special mention to the semi-arid ones. Holstein cows were measured for rectal temperature (T R), respiratory rate (F R) and rates of heat exchange by convection (C), radiation (R), skin surface evaporation (E S) and respiratory evaporation (E R) in the north eastern region of Brazil, after exposure to sun for several hours. Average environmental measurements during the observations were air temperature (T A) 32.4 °C (24.4-38.9°), wind speed (U) 1.8 m.s(-1) (0.01-11.0), relative humidity 63.6 % (36.8-81.5) and short-wave solar radiation 701.3 W m(-2) (116-1,295). The effective radiant heat load (ERHL) was 838.5 ± 4.9 W m(-2). Values for the atmospheric transmittance (τ) were also determined for tropical regions, in order to permit adequate estimates of the solar radiation. The average value was τ = 0.611 ± 0.004 for clear days with some small moving clouds, with a range of 0.32 to 0.91 in the day period from 1000 to 1300 hours. Observed τ values were higher (0.62-0.66) for locations near the seacoast and in those regions well-provided with green fields. Effects of month, location and time of the day were all statistically significant (P < 0.01). A total of 1,092 data were obtained for cows exposed for 1 to 8 h to sun during the day; in 7 months (February, March, April, July, August, September and November), 4 days per month on the average. A principal component analysis summarised the T R, F R, C, R, E S and E R measurements into just one synthetic variable (y 1); several indexes were then obtained by multiple regression of y 1 on the four environmental variables and its combinations, by using Origin 8.1 software (OriginLab Corp.). The chosen equation was the index of thermal stress for cows, ITSC = 77.1747 + 4.8327 T A - 34.8189 U + 1.111 U (2) + 118.6981 P V - 14.7956 P V (2) - 0.1059 ERHL with r (2) = 0.812. The

  1. Advances in environmental radiation protection: re-thinking animal-environment interaction modelling for wildlife dose assessment

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Michael D. [School of Environment and Life Sciences, University of Salford, Manchester, M4 4WT (United Kingdom); Beresford, Nicholas A. [School of Environment and Life Sciences, University of Salford, Manchester, M4 4WT (United Kingdom); Centre for Ecology and Hydrology, Bailrigg, Lancaster, LA1 4AP (United Kingdom); Bradshaw, Clare [Department of Ecology, Environment and Plant Sciences, Stockholm University, 10691 Stockholm (Sweden); Gashchak, Sergey [Chornobyl Centre for Nuclear Safety, Radioactive Waste and Radioecology, 07100 Slavutych (Ukraine); Hinton, Thomas G. [Institut de Radioprotection et de Surete Nucleaire (IRSN), Centre de Cadarache, 13115 Saint Paul-lez-Durance (France)

    2014-07-01

    Current wildlife dose assessment models adopt simplistic approaches to the representation of animal-environment interaction. The simplest approaches are to assume either that environmental media (e.g. soil, sediment or water) are uniformly contaminated or relating organism exposure to activity concentrations in media collected at the point of sampling of the animal. The external exposure of a reference organism is then estimated by defining the geometric relationship between the organism and the medium. For example, a reference organism within the soil would have a 4p exposure geometry and a reference organism on the soil would have a 2p exposure geometry. At best, the current modelling approaches recognise differences in media activity concentrations by calculating exposure for different areas of contamination and then estimating the fraction of time that an organism spends in each area. In other fields of pollution ecology, for example wildlife risk assessment for chemical pollution, more advanced approaches are being implemented to model animal-environment interaction and estimate exposure. These approaches include individual-based movement modelling and random walk modelling and a variety of software tools have been developed to facilitate the implementation of these models. Although there are more advanced animal-environment interaction modelling approaches that are available, it is questionable whether these should be adopted for use in environmental radiation protection. Would their adoption significantly reduce uncertainty within the assessment process and, if so, by how much? These questions are being addressed within the new TREE (TRansfer - Exposure - Effects) research programme funded by the United Kingdom Natural Environment Research Council (NERC) and within Working Group (WG) 8 of the International Atomic Energy Agency's MODARIA programme. MODARIA WG8 is reviewing some of the alternative approaches that have been developed for animal-environment

  2. An evaluation of radiation exposures in a tropical phosphogypsum disposal environment.

    Science.gov (United States)

    Haridasan, P P; Pillai, P M B; Tripathi, R M; Puranik, V D

    2009-07-01

    Environmental radiological aspects of phosphatic fertiliser production with particular reference to disposal of phosphogypsum at two sites in India are examined. Concentration of uranium and its decay products in the rock phosphate and products are presented. External gamma exposure and inhalation of radon and progeny are found to be the major routes of exposure to public in phosphogypsum disposal environment. An estimate of the committed effective dose to a representative person gives an average additional dose of 0.6 mSv annually in the study sites.

  3. Test beam evaluation of newly developed n-in-p planar pixel sensors for use in a high radiation environment

    Science.gov (United States)

    Kimura, K.; Yamaguchi, D.; Motohashi, K.; Nakamura, K.; Unno, Y.; Jinnouchi, O.; Altenheiner, S.; Blue, A.; Bomben, M.; Butter, A.; Cervelli, A.; Crawley, S.; Ducourthial, A.; Gisen, A.; Hagihara, M.; Hanagaki, K.; Hara, K.; Hirose, M.; Homma, Y.; Ikegami, Y.; Kamada, S.; Kono, T.; Macchiolo, A.; Marchiori, G.; Meloni, F.; Milovanovic, M.; Morton, A.; Mullier, G.; Munoz, F. J.; Nellist, C.; Paschen, B.; Quadt, A.; Rashid, T.; Rieger, J.; Rummler, A.; Sato, K.; Sato, K.; Savic, N.; Sawai, H.; Sexton, K.; Stramaglia, M. E.; Swiatlowski, M.; Takashima, R.; Takubo, Y.; Terzo, S.; Todome, K.; Tojo, J.; Houten, K. Van; Weingarten, J.; Wonsak, S.; Wraight, K.; Yamamura, K.

    2016-09-01

    Radiation-tolerant n-in-p planar pixel sensors have been under development in cooperation with Hamamatsu Photonics K.K. (HPK). This is geared towards applications in high-radiation environments, such as for the future Inner Tracker (ITk) placed in the innermost part of the ATLAS detector in the high luminosity LHC (HL-LHC) experiment. Prototypes of those sensors have been produced, irradiated, and evaluated over the last few years. In the previous studies, it was reported that significant drops in the detection efficiency were observed after irradiation, especially under bias structures. The bias structures are made up of poly-Si or Al bias rails and poly-Si bias resistors. The structure is implemented on the sensors to allow quality checks to be performed before the bump-bonding process, and to ensure that charge generated in floating pixels due to non-contacting or missing bump-bonds is dumped in a controlled way in order to avoid noise. To minimize the efficiency drop, several new pixel structures have been designed with bias rails and bias resistors relocated. Several test beams have been carried out to evaluate the drops in the detection efficiency of the new sensor structures after irradiation. Newly developed sensor modules were irradiated with proton-beams at the Cyclotron and Radio-Isotope Center (CYRIC) in Tohoku University to see the effect of sensor-bulk damage and surface charge-up. An irradiation with γ-rays was also carried out at Takasaki Advanced Radiation Research Center, with the goal of decoupling the effect of surface charge-up from that of bulk damage. Those irradiated sensors have been evaluated with particle beams at DESY and CERN. Comparison between different sensor structures confirmed significant improvements in minimizing efficiency loss under the bias structures after irradiation. The results from γ-irradiation also enabled cross-checking the results of a semiconductor technology simulation program (TCAD).

  4. Performance of high speed ball bearings with lead plated retainers in liquid hydrogen for potential use in a radiation environment

    Science.gov (United States)

    Wisander, D. W.; Brewe, D. E.; Scibbe, H. W.

    1972-01-01

    Ball bearings (40-mm bore) with lead coated, aluminum-bronze retainers were operated successfully in liquid hydrogen at 30,000 rpm under a thrust load of 1780 newtons (400 lb) for running times up to 15 hours. The lead transfer films on the bearing surfaces prevented galling of bearing components. The lead coated retainers used in this investigation show promise for use in the high radiation environments, where polytetrafluoroethylene (PTFE) based materials are not suitable. Failure was a result of the loss of lead lubricant on the retainer-inner-land and ball-pocket surfaces. The longest bearing life (15 hr) was achieved with a lead coating thickness of 50 micrometers (0.002 in.) on the retainer. Other bearings had lives of 2 to 6 hours.

  5. Monte Carlo simulation of the radiation environment encountered by a biochip during a space mission to Mars.

    Science.gov (United States)

    Le Postollec, A; Incerti, S; Dobrijevic, M; Desorgher, L; Santin, G; Moretto, P; Vandenabeele-Trambouze, O; Coussot, G; Dartnell, L; Nieminen, P

    2009-04-01

    Simulations with a Monte Carlo tool kit have been performed to determine the radiation environment a specific device, called a biochip, would face if it were placed into a rover bound to explore Mars' surface. A biochip is a miniaturized device that can be used to detect organic molecules in situ. Its specific detection part is constituted of proteins whose behavior under cosmic radiation is completely unknown and must be investigated to ensure a good functioning of the device under space conditions. The aim of this study is to define particle species and energy ranges that could be relevant to investigate during experiments on irradiation beam facilities. Several primary particles have been considered for galactic cosmic ray (GCR) and solar energetic particle (SEP) contributions. Ionizing doses accumulated in the biochip and differential fluxes of protons, alphas, neutrons, gammas, and electrons have been established for both the Earth-Mars transit and the journey at Mars' surface. Neutrons and gammas appear as dominant species on martian soil, whereas protons dominate during the interplanetary travel. Depending on solar event occurrence during the mission, an ionizing dose of around a few Grays (1 Gy = 100 rad) is expected.

  6. Beam test of novel n-in-p strip sensors for high radiation environment

    Energy Technology Data Exchange (ETDEWEB)

    Kubota, T., E-mail: kubota@hep.phys.titech.ac.jp [Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Kishida, T.; Jinnouchi, O. [Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Ikegami, Y.; Unno, Y.; Terada, S.; Mitsui, S. [Institute of Particle and Nuclear Study, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba-shi, Ibaraki 305-0801 (Japan); Tamii, A.; Aoi, T. [Research Center of Nuclear Physics (RCNP), 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Hanagaki, K. [Department of Physics, Osaka University, Machikaneyama-cho, Toyonaka-shi, Osaka 560-0043 (Japan); Hara, K. [Institute of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba-shi, Ibaraki 305-8571 (Japan); Kimura, N. [Research Institute for Science and Engineering, Waseda University (Japan); Takashima, R. [Department of Education, Kyoto University of Education, 1 Fukakusa-Fujimori-cho, Fushimi-ku, Kyoto 612-8522 (Japan); Takubo, Y. [Institute of Particle and Nuclear Study, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba-shi, Ibaraki 305-0801 (Japan); Tojo, J. [Department of Physics, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Nagai, K. [Institute of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba-shi, Ibaraki 305-8571 (Japan); Nakano, I. [Department of Physics, Okayama University, 3-1-1 Tshushima-naka, Kita-ku, Okayama-shi, Okayama 700-8530 (Japan); Yorita, K. [Research Institute for Science and Engineering, Waseda University (Japan)

    2013-12-11

    Highly radiation tolerant n-in-p strip sensors have been developed for the high-luminosity LHC (HL-LHC). This paper reports the results of measurements with 392 MeV kinetic energy proton beam at RCNP in December 2011. The data was taken with a new DAQ system consisting of an universal read-out board ‘SEABAS’ and beam tracking telescopes whose spacial resolution is better than 5μm. The aim of this beam test is to evaluate the new 1 cm×1 cm n-in-p miniature sensors before and after 10{sup 15} n{sub eq} cm{sup −2} irradiation. The median charge of un-irradiated sensor is 6.2 fC at full depletion voltage, while the median charge after 10{sup 15} n{sub eq} cm{sup −2} irradiation of the sensor is 4.2 fC. The novel Punch-Through-Protection (PTP) has been implemented in these sensors. The length of active region of the sensor around PTP is observed to be decreased by 12μm in the irradiated sensors at 10{sup 15} n{sub eq} cm{sup −2}.

  7. Optimising the neutron environment of Radiation Portal Monitors: A computational study

    Science.gov (United States)

    Gilbert, Mark R.; Ghani, Zamir; McMillan, John E.; Packer, Lee W.

    2015-09-01

    Efficient and reliable detection of radiological or nuclear threats is a crucial part of national and international efforts to prevent terrorist activities. Radiation Portal Monitors (RPMs), which are deployed worldwide, are intended to interdict smuggled fissile material by detecting emissions of neutrons and gamma rays. However, considering the range and variety of threat sources, vehicular and shielding scenarios, and that only a small signature is present, it is important that the design of the RPMs allows these signatures to be accurately differentiated from the environmental background. Using Monte-Carlo neutron-transport simulations of a model 3He detector system we have conducted a parameter study to identify the optimum combination of detector shielding, moderation, and collimation that maximises the sensitivity of neutron-sensitive RPMs. These structures, which could be simply and cost-effectively added to existing RPMs, can improve the detector response by more than a factor of two relative to an unmodified, bare design. Furthermore, optimisation of the air gap surrounding the helium tubes also improves detector efficiency.

  8. Analysis of sublimation-cooled coated mirrors in convective and radiative environments.

    Science.gov (United States)

    Howe, J. T.; Green, M. J.

    1973-01-01

    Analytical solutions were obtained for the thermal response of a transpiration- or sublimation-cooled spherical mirror coating exposed to convective and radiative heating. The solutions allow unlimited spectral detail to be accounted for. Results indicate that transpiration-cooled thick coatings (1 cm) may withstand up to 10 kW/sq cm on a steady basis without excessive temperature rise for quartzlike materials with an internal absorption coefficient of 0.01 per cm. On a transient basis, fluxes up to 20 kW/sq cm can be accommodated for a second (cW laser exposure time), 4 kW/sq cm for 5 sec (planetary entry heating time), and of the order of MW/sq cm for millisecond times (short-duration laser bursts) without transpiration cooling for a material with an absorption coefficient of 0.1 per cm. Proportionately higher fluxes can be accommodated with lower absorption coefficients. Thermal stresses produced by the heat pulse are found to be high but within the strength of the materials. The regime in which meaningful solutions may be obtained is mapped in detail.

  9. The effect of dispersed Petrobaltic oil droplet size on photosynthetically active radiation in marine environment.

    Science.gov (United States)

    Haule, Kamila; Freda, Włodzimierz

    2016-04-01

    Oil pollution in seawater, primarily visible on sea surface, becomes dispersed as an effect of wave mixing as well as chemical dispersant treatment, and forms spherical oil droplets. In this study, we examined the influence of oil droplet size of highly dispersed Petrobaltic crude on the underwater visible light flux and the inherent optical properties (IOPs) of seawater, including absorption, scattering, backscattering and attenuation coefficients. On the basis of measured data and Mie theory, we calculated the IOPs of dispersed Petrobaltic crude oil in constant concentration, but different log-normal size distributions. We also performed a radiative transfer analysis, in order to evaluate the influence on the downwelling irradiance Ed, remote sensing reflectance Rrs and diffuse reflectance R, using in situ data from the Baltic Sea. We found that during dispersion, there occurs a boundary size distribution characterized by a peak diameter d0  = 0.3 μm causing a maximum E d increase of 40% within 0.5-m depth, and the maximum Ed decrease of 100% at depths below 5 m. Moreover, we showed that the impact of size distribution on the "blue to green" ratios of Rrs and R varies from 24% increase to 27% decrease at the same crude oil concentration.

  10. Optimising the neutron environment of Radiation Portal Monitors: A computational study

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, Mark R., E-mail: mark.gilbert@ccfe.ac.uk [United Kingdom Atomic Energy Authority, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Ghani, Zamir [United Kingdom Atomic Energy Authority, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); McMillan, John E. [Department of Physics and Astronomy, University of Sheffield, Hicks building, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Packer, Lee W. [United Kingdom Atomic Energy Authority, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2015-09-21

    Efficient and reliable detection of radiological or nuclear threats is a crucial part of national and international efforts to prevent terrorist activities. Radiation Portal Monitors (RPMs), which are deployed worldwide, are intended to interdict smuggled fissile material by detecting emissions of neutrons and gamma rays. However, considering the range and variety of threat sources, vehicular and shielding scenarios, and that only a small signature is present, it is important that the design of the RPMs allows these signatures to be accurately differentiated from the environmental background. Using Monte-Carlo neutron-transport simulations of a model {sup 3}He detector system we have conducted a parameter study to identify the optimum combination of detector shielding, moderation, and collimation that maximises the sensitivity of neutron-sensitive RPMs. These structures, which could be simply and cost-effectively added to existing RPMs, can improve the detector response by more than a factor of two relative to an unmodified, bare design. Furthermore, optimisation of the air gap surrounding the helium tubes also improves detector efficiency.

  11. Convergent evolution of SWS2 opsin facilitates adaptive radiation of threespine stickleback into different light environments.

    Science.gov (United States)

    Marques, David A; Taylor, John S; Jones, Felicity C; Di Palma, Federica; Kingsley, David M; Reimchen, Thomas E

    2017-04-01

    Repeated adaptation to a new environment often leads to convergent phenotypic changes whose underlying genetic mechanisms are rarely known. Here, we study adaptation of color vision in threespine stickleback during the repeated postglacial colonization of clearwater and blackwater lakes in the Haida Gwaii archipelago. We use whole genomes from 16 clearwater and 12 blackwater populations, and a selection experiment, in which stickleback were transplanted from a blackwater lake into an uninhabited clearwater pond and resampled after 19 y to test for selection on cone opsin genes. Patterns of haplotype homozygosity, genetic diversity, site frequency spectra, and allele-frequency change support a selective sweep centered on the adjacent blue- and red-light sensitive opsins SWS2 and LWS. The haplotype under selection carries seven amino acid changes in SWS2, including two changes known to cause a red-shift in light absorption, and is favored in blackwater lakes but disfavored in the clearwater habitat of the transplant population. Remarkably, the same red-shifting amino acid changes occurred after the duplication of SWS2 198 million years ago, in the ancestor of most spiny-rayed fish. Two distantly related fish species, bluefin killifish and black bream, express these old paralogs divergently in black- and clearwater habitats, while sticklebacks lost one paralog. Our study thus shows that convergent adaptation to the same environment can involve the same genetic changes on very different evolutionary time scales by reevolving lost mutations and reusing them repeatedly from standing genetic variation.

  12. Gamma radiation levels in the ambient environment of the QNPP Base

    Institute of Scientific and Technical Information of China (English)

    WENG Jianqing; HE Jun; XIANG Yuanyi; WANG Kan; LI Xia; HAN Zhengdong

    2007-01-01

    Monitoring results of gamma dose rate level in 1992-2004 in the ambient environment of the Qinshan Nuclear Power Plants(QNPP)Base,the northeast of Zhejiang Province.are reported in this paper.It is shown that the gamma dose rate of five monitoring sites of 2.5 km to QNPP Base is 84-113 nGy/h.with an average of 96 nGy/h in the 13 years.The average value is close to the background level of 93 nGy/h prior to operation of the QNPP Base,and is lower than the monitoring result of 101 nGy/h at the reference site in Hangzhou City.Within 50 km from the QNPP Base,the cumnlative dose rate of the thermoluminescent dosimeter(TLD)is 90 nGy/h,which is lower than the background level of 111 nGy/h.

  13. Preliminary Circuit Design for Robotics Environment Mapping Utilizing Ambient Light, Reflected Light and Stationary Infrared Radiation

    Science.gov (United States)

    Adrian, Leslie

    2011-01-01

    The paper deals with robotics mobility and a proposed topology for the acquisition of the necessary data to enable accurate mapping of a given environment, be that for basic maneuverability, (obstacle avoidance) or for higher level applications such as fire detection or item location. The topology is composed of a four layered system of analogue components which lends itself not only to excellent linearity but allows the system to control peripheral devices directly through any logic configuration, or to provide data needed for microcontrollers and their user defined algorithms. The various layers have been analyzed through simulation and to date confirmed though physical observation of the working model. The conclusions about the prospective solution are made.

  14. Managing NIF safety equipment in a high neutron and gamma radiation environment.

    Science.gov (United States)

    Datte, Philip; Eckart, Mark; Jackson, Mark; Khater, Hesham; Manuel, Stacie; Newton, Mark

    2013-06-01

    The National Ignition Facility (NIF) is a 192 laser beam facility that supports the Inertial Confinement Fusion program. During the ignition experimental campaign, the NIF is expected to perform shots with varying fusion yield producing 14 MeV neutrons up to 20 MJ or 7.1 × 10(18) neutrons per shot and a maximum annual yield of 1,200 MJ. Several infrastructure support systems will be exposed to varying high yield shots over the facility's 30-y life span. In response to this potential exposure, analysis and testing of several facility safety systems have been conducted. A detailed MCNP (Monte Carlo N-Particle Transport Code) model has been developed for the NIF facility, and it includes most of the major structures inside the Target Bay. The model has been used in the simulation of expected neutron and gamma fluences throughout the Target Bay. Radiation susceptible components were identified and tested to fluences greater than 10(13) (n cm(-2)) for 14 MeV neutrons and γ-ray equivalent. The testing includes component irradiation using a 60Co gamma source and accelerator-based irradiation using 4- and 14- MeV neutron sources. The subsystem implementation in the facility is based on the fluence estimates after shielding and survivability guidelines derived from the dose maps and component tests results. This paper reports on the evaluation and implementation of mitigations for several infrastructure safety support systems, including video, oxygen monitoring, pressure monitors, water sensing systems, and access control interfaces found at the NIF.

  15. The effect of nutrients shortage on plant's efficiency to capture solar radiations under semi-arid environments.

    Science.gov (United States)

    Hammad, Hafiz Mohkum; Abbas, Farhat; Ahmad, Ashfaq; Fahad, Shah; Laghari, Khalifa Qasim; Alharby, Hesham; Farhad, Wajid

    2016-10-01

    Radiation use efficiency (RUE) is considered critical for calculation of crop yield. The crop productivity can be improved by increasing the interception of solar radiation and maintaining higher RUE for plants. Irrigation water and nitrogen (N) supply are the main limiting factors for RUE in maize (Zea mays L.) across the semi-arid environments. Field experiments were conducted during two consecutive growing seasons (2009-2010) to optimize RUE in relation to N application timings and rates with varying irrigation water management practices. In experiment 1, three N application timings were made, while in experiment 2, three possible water management practices were used. In both experiments, five N rates (100, 150, 200, 250, and 300 kg N ha(-1)) were applied to evaluate the effects of irrigation water and N on cumulative photosynthetic active radiation (PARi), dry matter RUE (RUEDM), and grain yield RUE (RUEGY). The results demonstrated that cumulative PARi and RUEs were not constant during the plant growth under varying the nutrients. The water and N significantly influenced cumulative PARi and RUEs during the both growing seasons. In experiment 1, the maximum cumulative PARi was observed by application of 250 kg N ha(-1) in three splits (1/3 N at V2, 1/3 N at V16, and 1/3 N at R1 stage), and the highest RUEDM was achieved by the application of 300 kg N ha(-1). However, the highest RUEGY was observed by application of 250 kg N ha(-1). In experiment 2, the maximum cumulative PARi was attained at normal irrigation regime with 250 kg N ha(-1), while the highest RUEDM and RUEGY were recorded at normal irrigation regime with the application of 300 kg N ha(-1). The regression analysis showed significant and positive correlation of RUEGY with grain yield. Therefore, optimum water and N doses are important for attaining higher RUE, which may enhance maize grain yield semi-arid environment; this may be considered in formulating good agricultural practices

  16. Radiation Engineering for Designers

    Science.gov (United States)

    Pellish, Jonathan A.

    2015-01-01

    This tutorial provides an overview of the natural space radiation environment, an introduction to radiation effect types, an overview of EEE parts selection, scrubbing, and radiation mitigation, and an introduction to radiation testing.

  17. Radiation Engineering for Designers

    Science.gov (United States)

    Pellish, Jonathan A.

    2015-01-01

    This tutorial provides an overview of the natural space radiation environment, an introduction to radiation effect types, an overview of EEE parts selection, scrubbing, and radiation mitigation, and an introduction to radiation testing.

  18. Adverse Impact of Electromagnetic Radiation on Urban Environment and Natural Resources using Optical Sensors

    Science.gov (United States)

    Kumar, Pawan; Katiyar, Swati; Rani, Meenu

    2016-07-01

    We are living in the age of a rapidly growing population and changing environmental conditions with an advance technical capacity.This has resulted in wide spread land cover change. One of the main causes for increasing urban heat is that more than half of the world's population lives in a rapidly growing urbanized environment. Satellite data can be highly useful to map change in land cover and other environmental phenomena with the passage of time. Among several human-induced environmental and urban thermal problems are reported to be negatively affecting urban residents in many ways. The built-up structures in urbanized areas considerably alter land cover thereby affecting thermal energy flow which leads to development of elevated surface and air temperature. The phenomenon Urban Heat Island implies 'island' of high temperature in cities, surrounded by relatively lower temperature in rural areas. The UHI for the temporal period is estimated using geospatial techniques which are then utilized for the impact assessment on climate of the surrounding regions and how it reduce the sustainability of the natural resources like air, vegetation. The present paper describes the methodology and resolution dynamic urban heat island change on climate using the geospatial approach. NDVI were generated using day time LANDSAT ETM+ image of 1990, 2000 and 2013. Temperature of various land use and land cover categories was estimated. Keywords: NDVI, Surface temperature, Dynamic changes.

  19. The challenges posed by radiation and radionuclide releases to the environment.

    Science.gov (United States)

    Wenning, Richard J; Apitz, Sabine E; Backhaus, Thomas; Barnthouse, Lawrence; Batley, Graeme; Brooks, Bryan; Chapman, Peter M; Griffin, Michael; Kapustka, Lawrence; Landis, Wayne; Leung, Kenneth M Y; Linkov, Igor; Seager, Thomas P; Suter, Glenn; Tannenbaum, Lawrence

    2011-07-01

    The recent accident at the Fukushima I nuclear power plant in Japan (also known as Fukushima Daiichi) captured the world's attention and re-invigorated concerns about the safety of nuclear power technology. The Editors of Integrated Environmental Assessment and Management invited experts in the field to describe the primary issues associated with the control and release of radioactive materials to the environment, particularly those that are of importance to the health of the human populations and the ecological systems that populate our planet. This collection of invited short commentaries aims to inform on the safety of nuclear power plants damaged by natural disasters and provide a primer on the potential environmental impacts. The intent of these invited commentaries is not to fuel the excitement and fears about the Fukushima Daiichi incident; rather, it is to collect views and comments from some of the world's experts on the broad science and policy challenges raised by this event, and to provide high-level views on the science issues that surround this situation in order to improve our collective ability to avoid or at least minimize the consequences of future events.

  20. Radiation Environment at LEO in the frame of Space Monitoring Data Center at Moscow State University - recent, current and future missions

    Science.gov (United States)

    Myagkova, Irina; Kalegaev, Vladimir; Panasyuk, Mikhail; Svertilov, Sergey; Bogomolov, Vitaly; Bogomolov, Andrey; Barinova, Vera; Barinov, Oleg; Bobrovnikov, Sergey; Dolenko, Sergey; Mukhametdinova, Ludmila; Shiroky, Vladimir; Shugay, Julia

    2016-04-01

    Radiation Environment of Near-Earth space is one of the most important factors of space weather. Space Monitoring Data Center of Moscow State University provides operational control of radiation conditions at Low Earth's Orbits (LEO) of the near-Earth space using data of recent (Vernov, CORONAS series), current (Meteor-M, Electro-L series) and future (Lomonosov) space missions. Internet portal of Space Monitoring Data Center of Skobeltsyn Institute of Nuclear Physics of Lomonosov Moscow State University (SINP MSU) http://swx.sinp.msu.ru/ provides possibilities to control and analyze the space radiation conditions in the real time mode together with the geomagnetic and solar activity including hard X-ray and gamma- emission of solar flares. Operational data obtained from space missions at L1, GEO and LEO and from the Earth's magnetic stations are used to represent radiation and geomagnetic state of near-Earth environment. The models of space environment that use space measurements from different orbits were created. Interactive analysis and operational neural network forecast services are based on these models. These systems can automatically generate alerts on particle fluxes enhancements above the threshold values, both for SEP and relativistic electrons of outer Earth's radiation belt using data from GEO and LEO as input. As an example of LEO data we consider data from Vernov mission, which was launched into solar-synchronous orbit (altitude 640 - 83 0 km, inclination 98.4°, orbital period about 100 min) on July 8, 2014 and began to receive scientific information since July 20, 2014. Vernov mission have provided studies of the Earth's radiation belt relativistic electron precipitation and its possible connection with atmosphere transient luminous events, as well as the solar hard X-ray and gamma-emission measurements. Radiation and electromagnetic environment monitoring in the near-Earth Space, which is very important for space weather study, was also realised

  1. Radiation Environment at GEO from the FY2G Satellite Observations

    Science.gov (United States)

    Wang, C.

    2016-12-01

    WANG Chun-Qin1,2*, Zhang Shen-Yi1,2 Jing Tao1,2, Zhang Huan-Xin1,2 Li Jia-Wei3 Zhang Xiao-Xin3 Sun Yue-Qiang1,2 Liang Jin-Bao1,2 Wei Fei1,2 Shen Guo-Hong1,2 Huang Cong3 Shi Chun-Yan1,21.National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China; 2.Beijing Key Laboratory of Space Environment Exploration, Beijing 100190,China 3.National Satellite Meteorological Center, National Center for Space Weather, Beijing 100081, China; Abstract Recent measurements of the high energy electrons and protons with energetic particle instrument carried on the FY-2G satellite are presented. The instrument consist of two detectors-the high energy electrons instrument which can measure 200keV to greater than 4MeV electrons with eleven channels, and the high energy protons and heavy ions instrument which mainly senses incident flux of solar protons with seven channels from 4MeV to 300 MeV. The paper shows electrons and protons observations from Jan 2015 until Oct 2015. A precise description and preliminary analysis of particle dynamic during disturbances of magnetic storms、substorms and solar eruptions suggest that both of the detectors show accurate response to various disturbances and provide refined particles data. Comparison results of FY2G satellite with GOES series satellites reflect obvious local difference in particle flux evolvement especially during intensive disturbances time, which can be helpful for data assimilation of multi-satellite as well as further research in more complicated magnetosphere energy particle dynamic.

  2. Toward a web-based real-time radiation treatment planning system in a cloud computing environment

    Science.gov (United States)

    Hum Na, Yong; Suh, Tae-Suk; Kapp, Daniel S.; Xing, Lei

    2013-09-01

    To exploit the potential dosimetric advantages of intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT), an in-depth approach is required to provide efficient computing methods. This needs to incorporate clinically related organ specific constraints, Monte Carlo (MC) dose calculations, and large-scale plan optimization. This paper describes our first steps toward a web-based real-time radiation treatment planning system in a cloud computing environment (CCE). The Amazon Elastic Compute Cloud (EC2) with a master node (named m2.xlarge containing 17.1 GB of memory, two virtual cores with 3.25 EC2 Compute Units each, 420 GB of instance storage, 64-bit platform) is used as the backbone of cloud computing for dose calculation and plan optimization. The master node is able to scale the workers on an ‘on-demand’ basis. MC dose calculation is employed to generate accurate beamlet dose kernels by parallel tasks. The intensity modulation optimization uses total-variation regularization (TVR) and generates piecewise constant fluence maps for each initial beam direction in a distributed manner over the CCE. The optimized fluence maps are segmented into deliverable apertures. The shape of each aperture is iteratively rectified to be a sequence of arcs using the manufacture’s constraints. The output plan file from the EC2 is sent to the simple storage service. Three de-identified clinical cancer treatment plans have been studied for evaluating the performance of the new planning platform with 6 MV flattening filter free beams (40 × 40 cm2) from the Varian TrueBeamTM STx linear accelerator. A CCE leads to speed-ups of up to 14-fold for both dose kernel calculations and plan optimizations in the head and neck, lung, and prostate cancer cases considered in this study. The proposed system relies on a CCE that is able to provide an infrastructure for parallel and distributed computing. The resultant plans from the cloud computing are identical

  3. Test beam evaluation of newly developed n-in-p planar pixel sensors for use in a high radiation environment

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, K., E-mail: kimihiko@hep.phys.titech.ac.jp [Institute of Science and Engineering, Tokyo Institute of Technology, Ookayama 2-12-1, Meguro-ku, Tokyo 152-8551 (Japan); Yamaguchi, D.; Motohashi, K. [Institute of Science and Engineering, Tokyo Institute of Technology, Ookayama 2-12-1, Meguro-ku, Tokyo 152-8551 (Japan); Nakamura, K.; Unno, Y. [Institute of Particle and Nuclear Study, KEK, Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Jinnouchi, O. [Institute of Science and Engineering, Tokyo Institute of Technology, Ookayama 2-12-1, Meguro-ku, Tokyo 152-8551 (Japan); Altenheiner, S. [Experimentelle Physik IV, Technische Universität Dortmund, 44221 Dortmund (Germany); Blue, A. [School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, Scotland (United Kingdom); Bomben, M. [CNRS/IN2P3 (France); Laboratoire de physique nucléaire et de hautes energies (LPNHE), Univ. Paris-UMPC, 4 Place Jussieu, 75005 Paris (France); Univ. Paris Diderot (France); Butter, A. [LAL, University Paris-Sud (France); CNRS/IN2P3 (France); Université Paris-Saclay, Orsay (France); Cervelli, A. [Universität Bern, Laboratory for High Energy Physics, Sidlerstrasse 55, CH-3012 Bern (Switzerland); Crawley, S. [School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, Scotland (United Kingdom); Ducourthial, A. [CNRS/IN2P3 (France); Laboratoire de physique nucléaire et de hautes energies (LPNHE), Univ. Paris-UMPC, 4 Place Jussieu, 75005 Paris (France); Univ. Paris Diderot (France); Gisen, A. [Experimentelle Physik IV, Technische Universität Dortmund, 44221 Dortmund (Germany); Hagihara, M. [Institute of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8751 (Japan); and others

    2016-09-21

    Radiation-tolerant n-in-p planar pixel sensors have been under development in cooperation with Hamamatsu Photonics K.K. (HPK). This is geared towards applications in high-radiation environments, such as for the future Inner Tracker (ITk) placed in the innermost part of the ATLAS detector in the high luminosity LHC (HL-LHC) experiment. Prototypes of those sensors have been produced, irradiated, and evaluated over the last few years. In the previous studies, it was reported that significant drops in the detection efficiency were observed after irradiation, especially under bias structures. The bias structures are made up of poly-Si or Al bias rails and poly-Si bias resistors. The structure is implemented on the sensors to allow quality checks to be performed before the bump-bonding process, and to ensure that charge generated in floating pixels due to non-contacting or missing bump-bonds is dumped in a controlled way in order to avoid noise. To minimize the efficiency drop, several new pixel structures have been designed with bias rails and bias resistors relocated. Several test beams have been carried out to evaluate the drops in the detection efficiency of the new sensor structures after irradiation. Newly developed sensor modules were irradiated with proton-beams at the Cyclotron and Radio-Isotope Center (CYRIC) in Tohoku University to see the effect of sensor-bulk damage and surface charge-up. An irradiation with γ-rays was also carried out at Takasaki Advanced Radiation Research Center, with the goal of decoupling the effect of surface charge-up from that of bulk damage. Those irradiated sensors have been evaluated with particle beams at DESY and CERN. Comparison between different sensor structures confirmed significant improvements in minimizing efficiency loss under the bias structures after irradiation. The results from γ-irradiation also enabled cross-checking the results of a semiconductor technology simulation program (TCAD). - Highlights: • The

  4. Toward a web-based real-time radiation treatment planning system in a cloud computing environment.

    Science.gov (United States)

    Na, Yong Hum; Suh, Tae-Suk; Kapp, Daniel S; Xing, Lei

    2013-09-21

    To exploit the potential dosimetric advantages of intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT), an in-depth approach is required to provide efficient computing methods. This needs to incorporate clinically related organ specific constraints, Monte Carlo (MC) dose calculations, and large-scale plan optimization. This paper describes our first steps toward a web-based real-time radiation treatment planning system in a cloud computing environment (CCE). The Amazon Elastic Compute Cloud (EC2) with a master node (named m2.xlarge containing 17.1 GB of memory, two virtual cores with 3.25 EC2 Compute Units each, 420 GB of instance storage, 64-bit platform) is used as the backbone of cloud computing for dose calculation and plan optimization. The master node is able to scale the workers on an 'on-demand' basis. MC dose calculation is employed to generate accurate beamlet dose kernels by parallel tasks. The intensity modulation optimization uses total-variation regularization (TVR) and generates piecewise constant fluence maps for each initial beam direction in a distributed manner over the CCE. The optimized fluence maps are segmented into deliverable apertures. The shape of each aperture is iteratively rectified to be a sequence of arcs using the manufacture's constraints. The output plan file from the EC2 is sent to the simple storage service. Three de-identified clinical cancer treatment plans have been studied for evaluating the performance of the new planning platform with 6 MV flattening filter free beams (40 × 40 cm(2)) from the Varian TrueBeam(TM) STx linear accelerator. A CCE leads to speed-ups of up to 14-fold for both dose kernel calculations and plan optimizations in the head and neck, lung, and prostate cancer cases considered in this study. The proposed system relies on a CCE that is able to provide an infrastructure for parallel and distributed computing. The resultant plans from the cloud computing are

  5. Development of an active detector for the characterization of the late-time radiation environment from a reactor pulse

    Energy Technology Data Exchange (ETDEWEB)

    Luker, S.M. [Applied Nuclear Technologies, Sandia National Laboratories, Mail Stop 1146, P.O. Box 5800, Albuquerque, NM 87185-1146 (United States); Griffin, P.J. [Nuclear Facility Operations, Sandia National Laboratories, Mail Stop 0614, P.O. Box 5800, Albuquerque, NM 87185-1146 (United States); Kolb, N.R. [Applied Nuclear Technologies, Sandia National Laboratories, Mail Stop 0982, P.O. Box 5800, Albuquerque, NM 87185-0982 (United States); Naranjo, G.N. [Advanced Nuclear Concepts, Sandia National Laboratories, Mail Stop 1143, P.O. Box 5800, Albuquerque, NM 87185-1143 (United States); Suo-Anttila, A.J. [Computational Engineering Analysis LLC, Albuquerque, NM 87111 (United States)

    2011-07-01

    Document available in abstract form only, full text of document follows: This paper discusses the use of a commercially available {sup 235}U fission chamber, with a matching compensating ion chamber, originally sold as a single-ended detector with the signal conducted over the shield of a coaxial cable. The authors designed an aluminum housing that isolates the two detectors and converts the signals to full differential mode as a noise-reduction technique. The signals are processed using the switched resistor technique to extend the signal range to longer times from the peak of the pulse [Luker, S. M., Griffin, P. J., King, D. B., and Suo-Anttila, A. J., 'Improved Diagnostics for Analysis of a Reactor Pulse Radiation Environment,' 13. International Symposium on Reactor Dosimetry, Akersloot, Netherlands, May 25, 2008, pp. 4-6.]. The newly configured fission chamber assembly has been used at the annular core research reactor at Sandia National Laboratories to provide a high-fidelity characterization of the neutron time profile from a pulsed operation. (authors)

  6. Oxygen atom transfer reactions from dioxygen to phosphines via a bridging sulfur dioxide in a trinuclear cluster complex of rhenium, [(Ph(3)P)(2)N][Re(3)(mu(3)-S)(mu-S)(2)(mu-SO(2))Cl(6)(PMe(2)Ph)(3)].

    Science.gov (United States)

    Saito, Taro; Sunaga, Tomoaki; Sakai, Nobuaki; Nakamura, Yoichi; Yamamoto, Saori; Iriuchijima, Daisuke; Yoza, Kenji

    2005-06-13

    A trinuclear rhenium sulfide cluster complex, [(Ph(3)P)(2)N][Re(3)(mu(3)-S)(mu-S)(3)Cl(6)(PMe(2)Ph)(3)], synthesized from Re(3)S(7)Cl(7), dimethylphenylphosphine, and [(Ph(3)P)(2)N]Cl is readily converted to a bridging SO(2) complex, [(Ph(3)P)(2)N][Re(3)(mu(3)-S)(mu-S)(2)(mu-SO(2))Cl(6)(PMe(2)Ph)(3)], by reaction with O(2). The oxygen atoms on the SO(2) ligand react with phosphines or phosphites to form phosphine oxides or phosphates, and the original cluster complex is recovered. The reaction course has been monitored by (31)P NMR as well as by UV-vis spectroscopy. The catalytic oxygenation of PMePh(2) in the presence of the SO(2) complex shows that turnovers are 8 per hour at 23 degrees C in CDCl(3). The X-ray structures of the cluster complexes are described.

  7. GENII-LIN-2.1: an open source software system for calculating radiation dose and risk from radionuclides released to the environment.

    Science.gov (United States)

    Teodori, Francesco; Sumini, Marco

    2008-12-01

    GENII-LIN is an open source radiation protection environmental software system running on the Linux operating system. It has capabilities for calculating radiation dose and risk to individuals or populations from radionuclides released to the environment and from pre-existing environmental contamination. It can handle exposure pathways that include ingestion, inhalation and direct exposure to air, water and soil. The package is available for free and is completely open source, i.e., transparent to the users, who have full access to the source code of the software.

  8. Scenario of a dirty bomb in an urban environment and acute management of radiation poisoning and injuries

    National Research Council Canada - National Science Library

    Chin, F K C

    2007-01-01

    .... This article examines two scenarios of radiation contamination and injury, one accidental in nature leading to environmental contamination, and another of deliberate intent resulting in injury and death...

  9. Adaptation strategies of endolithic chlorophototrophs to survive the hyperarid and extreme solar radiation environment of the Atacama Desert

    Directory of Open Access Journals (Sweden)

    Jacek eWierzchos

    2015-09-01

    Full Text Available The Atacama Desert, northern Chile, is one of the driest deserts on Earth and, as such, a natural laboratory to explore the limits of life and the strategies evolved by microorganisms to adapt to extreme environments. Here we report the exceptional adaptation strategies of chlorophototrophic and eukaryotic algae, and chlorophototrophic and prokaryotic cyanobacteria to the hyperarid and extremely high solar radiation conditions occurring in this desert. Our approach combined several microscopy techniques, spectroscopic analytical methods, and molecular analyses. We found that the major adaptation strategy was to avoid the extreme environmental conditions by colonizing cryptoendolithic, as well as, hypoendolithic habitats within gypsum deposits. The cryptoendolithic colonization occurred a few millimeters beneath the gypsum surface and showed a succession of organized horizons of algae and cyanobacteria, which has never been reported for endolithic microbial communities. The presence of cyanobacteria beneath the algal layer, in close contact with sepiolite inclusions, and their hypoendolithic colonization suggest that occasional liquid water might persist within these sub-microhabitats. We also identified the presence of abundant carotenoids in the upper cryptoendolithic algal habitat and scytonemin in the cyanobacteria hypoendolithic habitat. This study illustrates that successful lithobiontic microbial colonization at the limit for microbial life is the result of a combination of adaptive strategies to avoid excess solar irradiance and extreme evapotranspiration rates, taking advantage of the complex structural and mineralogical characteristics of gypsum deposits – conceptually called rock’s habitable architecture. Additionally self-protection by synthesis and accumulation of secondary metabolites likely produces a shielding effect that prevents photoinhibition and lethal photooxidative damage to the chlorophototrophs, representing another

  10. Adaptation strategies of endolithic chlorophototrophs to survive the hyperarid and extreme solar radiation environment of the Atacama Desert

    Science.gov (United States)

    Wierzchos, Jacek; DiRuggiero, Jocelyne; Vítek, Petr; Artieda, Octavio; Souza-Egipsy, Virginia; Škaloud, Pavel; Tisza, Michel; Davila, Alfonso F.; Vílchez, Carlos; Garbayo, Inés; Ascaso, Carmen

    2015-01-01

    The Atacama Desert, northern Chile, is one of the driest deserts on Earth and, as such, a natural laboratory to explore the limits of life and the strategies evolved by microorganisms to adapt to extreme environments. Here we report the exceptional adaptation strategies of chlorophototrophic and eukaryotic algae, and chlorophototrophic and prokaryotic cyanobacteria to the hyperarid and extremely high solar radiation conditions occurring in this desert. Our approach combined several microscopy techniques, spectroscopic analytical methods, and molecular analyses. We found that the major adaptation strategy was to avoid the extreme environmental conditions by colonizing cryptoendolithic, as well as, hypoendolithic habitats within gypsum deposits. The cryptoendolithic colonization occurred a few millimeters beneath the gypsum surface and showed a succession of organized horizons of algae and cyanobacteria, which has never been reported for endolithic microbial communities. The presence of cyanobacteria beneath the algal layer, in close contact with sepiolite inclusions, and their hypoendolithic colonization suggest that occasional liquid water might persist within these sub-microhabitats. We also identified the presence of abundant carotenoids in the upper cryptoendolithic algal habitat and scytonemin in the cyanobacteria hypoendolithic habitat. This study illustrates that successful lithobiontic microbial colonization at the limit for microbial life is the result of a combination of adaptive strategies to avoid excess solar irradiance and extreme evapotranspiration rates, taking advantage of the complex structural and mineralogical characteristics of gypsum deposits—conceptually called “rock's habitable architecture.” Additionally, self-protection by synthesis and accumulation of secondary metabolites likely produces a shielding effect that prevents photoinhibition and lethal photooxidative damage to the chlorophototrophs, representing another level of

  11. Adaptation strategies of endolithic chlorophototrophs to survive the hyperarid and extreme solar radiation environment of the Atacama Desert.

    Science.gov (United States)

    Wierzchos, Jacek; DiRuggiero, Jocelyne; Vítek, Petr; Artieda, Octavio; Souza-Egipsy, Virginia; Škaloud, Pavel; Tisza, Michel; Davila, Alfonso F; Vílchez, Carlos; Garbayo, Inés; Ascaso, Carmen

    2015-01-01

    The Atacama Desert, northern Chile, is one of the driest deserts on Earth and, as such, a natural laboratory to explore the limits of life and the strategies evolved by microorganisms to adapt to extreme environments. Here we report the exceptional adaptation strategies of chlorophototrophic and eukaryotic algae, and chlorophototrophic and prokaryotic cyanobacteria to the hyperarid and extremely high solar radiation conditions occurring in this desert. Our approach combined several microscopy techniques, spectroscopic analytical methods, and molecular analyses. We found that the major adaptation strategy was to avoid the extreme environmental conditions by colonizing cryptoendolithic, as well as, hypoendolithic habitats within gypsum deposits. The cryptoendolithic colonization occurred a few millimeters beneath the gypsum surface and showed a succession of organized horizons of algae and cyanobacteria, which has never been reported for endolithic microbial communities. The presence of cyanobacteria beneath the algal layer, in close contact with sepiolite inclusions, and their hypoendolithic colonization suggest that occasional liquid water might persist within these sub-microhabitats. We also identified the presence of abundant carotenoids in the upper cryptoendolithic algal habitat and scytonemin in the cyanobacteria hypoendolithic habitat. This study illustrates that successful lithobiontic microbial colonization at the limit for microbial life is the result of a combination of adaptive strategies to avoid excess solar irradiance and extreme evapotranspiration rates, taking advantage of the complex structural and mineralogical characteristics of gypsum deposits-conceptually called "rock's habitable architecture." Additionally, self-protection by synthesis and accumulation of secondary metabolites likely produces a shielding effect that prevents photoinhibition and lethal photooxidative damage to the chlorophototrophs, representing another level of adaptation.

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

    Energy Technology Data Exchange (ETDEWEB)

    Vega, Richard Manuel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Parma, Edward J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Naranjo, Gerald E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lippert, Lance L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Vehar, David W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Griffin, Patrick J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

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

  13. Man-made radionuclides in the environment and resulting radiation exposures; Anthropogene Radionuklide in der Umwelt und daraus resultierende Strahlenexpositionen

    Energy Technology Data Exchange (ETDEWEB)

    Michel, R. [Leibniz Univ. Hannover (Germany). Zentrum fuer Strahlenschutz und Radiooekologie

    2009-07-01

    This contribution gives a survey about the sources of man-made environmental radioactivity and quantifies some of the resulting radiation exposures. The relevance of the different radionuclides with respect to the radiation exposures is discussed. Finally, the question of the effects of small doses is addressed. (orig.)

  14. The radiation environment on the surface of Mars - Numerical calculations of the galactic component with GEANT4/PLANETOCOSMICS

    Science.gov (United States)

    Matthiä, Daniel; Berger, Thomas

    2017-08-01

    Galactic cosmic radiation and secondary particles produced in the interaction with the atmosphere lead to a complex radiation field on the Martian surface. A workshop (;1st Mars Space Radiation Modeling Workshop;) organized by the MSL-RAD science team was held in June 2016 in Boulder with the goal to compare models capable to predict this radiation field with each other and measurements from the RAD instrument onboard the curiosity rover taken between November 15, 2015 and January 15, 2016. In this work the results of PLANETOCOSMICS/GEANT4 contributed to the workshop are presented. Calculated secondary particle spectra on the Martian surface are investigated and the radiation field's directionality of the different particles in dependence on the energy is discussed. Omnidirectional particle fluxes are used in combination with fluence to dose conversion factors to calculate absorbed dose rates and dose equivalent rates in a slab of tissue.

  15. The Sileye-3/Alteino experiment for the study of Light Flashes, radiation environment and astronaut brain activity on board the International Space Station

    Energy Technology Data Exchange (ETDEWEB)

    Bidoli, V.; Casolino, M.; Pascale, M.P. de [Rome Univ. (Italy)] [and others

    2002-12-01

    In this work we describe the instrument Sileye-3/Alteino, placed on board the International Space Station in April 2002. The instrument is constituted by an Electroencephalograph and a cosmic ray silicon detector. The scientific aims include the investigation of the Light Flash phenomenon, the measurement of the radiation environment and the nuclear abundance insider the International Space Station (ISS) and the study of astronaut brain activity in space when subject to cosmic rays. (author)

  16. Verification of a Monte-Carlo planetary surface radiation environment model using gamma-ray data from Lunar Prospector and 2001 Mars Odyssey

    Energy Technology Data Exchange (ETDEWEB)

    Skidmore, M.S., E-mail: mss16@star.le.ac.u [Space Research Centre, Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom); Ambrosi, R.M. [Space Research Centre, Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom)

    2010-01-01

    Characterising a planetary radiation environment is important to: (1) assess the habitability of a planetary body for indigenous life; (2) assess the risks associated with manned exploration missions to a planetary body and (3) predict/interpret the results that remote sensing instrumentation may obtain from a planetary body (e.g. interpret the gamma-ray emissions from a planetary surface produced by radioactive decay or via the interaction of galactic cosmic rays to obtain meaningful estimates of the concentration of certain elements on the surface of a planet). The University of Leicester is developing instrumentation for geophysical applications that include gamma-ray spectroscopy, gamma-ray densitometry and radiometric dating. This paper describes the verification of a Monte-Carlo planetary radiation environment model developed using the MCNPX code. The model is designed to model the radiation environments of Mars and the Moon, but is applicable to other planetary bodies, and will be used to predict the performance of the instrumentation being developed at Leicester. This study demonstrates that the modelled gamma-ray data is in good agreement with gamma-ray data obtained by the gamma-ray spectrometers on 2001 Mars Odyssey and Lunar Prospector, and can be used to accurately model geophysical instrumentation for planetary science applications.

  17. "BION-M" No. 1 spacecraft radiation environment as observed by the RD3-B3 radiometer-dosimeter in April-May 2013

    Science.gov (United States)

    Dachev, T. P.; Tomov, B. T.; Matviichuk, Yu. N.; Dimitrov, Pl. G.; Bankov, N. G.; Shurshakov, V. V.; Ivanova, O. A.; Häder, D.-P.; Schuster, M. T.; Reitz, G.; Horneck, G.

    2015-02-01

    Space radiation has been monitored using the РД3-Б3 (in the following we use the Latin transcription RD3-B3) spectrometer-dosimeter on board a recent space flight of the Russian recoverable satellite "BION-M" No. 1. The instrument was mounted inside the satellite in a pressurized volume together with biological objects and samples. The RD3-B3 instrument is a battery operated version of the spare model of the R3D-B3 instrument developed and built for the ESA BIOPAN-6 facility on Foton M3 satellite launched on September 2007 (Häder et al., 2009). It is a low mass, small dimension automated device that measures solar radiation in four channels and ionizing radiation in 256 channels of a Liulin-type energy deposition spectrometer (Dachev et al., 2002). Cosmic ionizing radiation has been monitored and separated in 256 deposited energy spectra, which were further used for determination of the absorbed dose rate and flux. The paper summarizes the results for the Earth radiation environment at the altitude of 253-585 km.

  18. High-Resolution and Analytical TEM Investigation of Space Radiation Processing Effects in Primitive Solar System Materials and Airless Planetary Surface Environments

    Science.gov (United States)

    Christoffersen, R.; Rahman, Z.; Keller, L. P.; Dukes, C.; Baragiola, R.

    2012-01-01

    Energetic ions present in the diverse plasma conditions in space play a significant role in the formation and modification of solid phases found in environments ranging from the interstellar medium (ISM) to the surfaces of airless bodies such as asteroids and the Moon. These effects are often referred to as space radiation processing, a term that encompasses changes induced in natural space-exposed materials that may be only structural, such as in radiation-induced amorphization, or may involve ion-induced nanoscale to microscale chemical changes, as occurs in preferential sputtering and ion-beam mixing. Ion sputtering in general may also be responsible for partial or complete erosion of space exposed materials, in some instances possibly bringing about the complete destruction of free-floating solid grains in the ISM or in circumstellar nebular dust clouds. We report here on two examples of the application of high-resolution and analytical transmission electron microscopy (TEM) to problems in space radiation processing. The first problem concerns the role of space radiation processing in controlling the overall fate of Fe sulfides as hosts for sulfur in the ISM. The second problem concerns the known, but as yet poorly quantified, role of space radiation processing in lunar space weathering.

  19. Development of cryogenic Si detectors by CERN RD39 Collaboration for ultra radiation hardness in SLHC environment

    CERN Document Server

    Li, Z; Anbinderis, P; Anbinderis, T; D’Ambrosio, N; de Boer, Wim; Borchi, E; Borer, K; Bruzzi, M; Buontempo, S; Chen, W; Cindro, V; Dierlamm, A; Eremin, V; Gaubas, E; Gorbatenko, V; Grigoriev, E; Hauler, F; Heijne, Erik H M; Heising, S; Hempel, O; Herzog, R; Härkönen, J; Ilyashenko, I; Janos, S; Jungermann, L; Kalesinskas, V; Kapturauskas, J; Laiho, R; Luukka, P; Mandic, I; De Masi, R; Menichelli, D; Mikuz, M; Militaru, O; Niinikosky, T O; O’Shea, V; Pagano, S; Paul, S; Piotrzkowski, K; Pretzl, K; Rato-Mendes, P; Rouby, X; Ruggiero, G; Smith, K; Sonderegger, P; Sousa, P; Tuominen, E; Tuovinen, E; Verbitskaya, E; Vaitkus, J; Wobst, E; Zavrtanik, M

    2007-01-01

    There are two key approaches in our CERN RD 39 Collaboration efforts to obtain ultra-radiation-hard Si detectors: (1) use of the charge/current injection to manipulate the detector internal electric field in such a way that it can be depleted at a modest bias voltage at cryogenic temperature range (150 K), and (2) freezing out of the trapping centers that affects the CCE at cryogenic temperatures lower than that of the liquid nitrogen (LN2) temperature. In our first approach, we have developed the advanced radiation hard detectors using charge or current injection, the current injected diodes (CID). In a CID, the electric field is controlled by injected current, which is limited by the space charge, yielding a nearly uniform electric field in the detector, independent of the radiation fluence. In our second approach, we have developed models of radiation-induced trapping levels and the physics of their freezing out at cryogenic temperatures.

  20. Including the effects of a harsh radiation environment in the simulation and design of nanoelectronic devices and circuits Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Nanoelectronic devices, and circuits based on such devices, are expected to be more susceptible to the effects of radiation than the previous generation of devices...

  1. The effect of population structure on the adaptive radiation of microbial populations evolving in spatially structured environments

    NARCIS (Netherlands)

    Habets, M.G.J.L.; Rozen, D.; Hoekstra, R.F.; Visser, de J.A.G.M.

    2006-01-01

    Spatial structure is thought to be an important factor influencing the emergence and maintenance of genetic diversity. Previous studies have demonstrated that environmental heterogeneity, provided by spatial structure, leads to adaptive radiation of populations. In the present study, we investigate

  2. Atoms, Radiation, and Radiation Protection

    CERN Document Server

    Turner, James E

    2007-01-01

    Atoms, Radiation, and Radiation Protection offers professionals and advanced students a comprehensive coverage of the major concepts that underlie the origins and transport of ionizing radiation in matter. Understanding atomic structure and the physical mechanisms of radiation interactions is the foundation on which much of the current practice of radiological health protection is based. The work covers the detection and measurement of radiation and the statistical interpretation of the data. The procedures that are used to protect man and the environment from the potential harmful effects of

  3. Final Report – Study of Shortwave Spectra in Fully 3D Environment. Synergy Between Scanning Radars and Spectral Radiation Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Jui-Yuan [University of Reading (United Kingdom)

    2015-09-14

    ARM set out 20 years ago to “close” the radiation problem, that is, to improve radiation models to the point where they could routinely predict the observed spectral radiation fluxes knowing the optical properties of the surface and of gases, clouds and aerosols in the atmosphere. Only then could such radiation models form a proper springboard for global climate model (GCM) parameterizations of spectral radiation. Sustained efforts have more or less achieved that goal with regard to longwave radiation; ASR models now routinely predict ARM spectral longwave radiances to 1–2%. Similar efforts in the shortwave have achieved far less; the successes are mainly for carefully selected 1D stratiform cloud cases. Such cases amount, even with the most optimistic interpretation, to no more than 30% of all cases at SGP. The problem has not been lack of effort but lack of appropriate instruments.The new ARM stimulus-funded instruments, with their new capabilities, will dramatically improve this situation and once again make progress possible on the shortwave problem. The new shortwave spectrometers will provide a reliable, calibrated record including the near infrared – and for other climatic regimes than SGP. The new scanning radars will provide the 3D cloud view, making it possible to tackle fully 3D situations. Thus, our main theme for the project is the understanding and closure of the surface spectral shortwave radiation problem in fully 3D cloud situations by combining the new ARM scanning radars and shortwave spectrometers with the arsenal of radiative transfer tools.

  4. Assessment of effectiveness of geologic isolation systems. ARRRG and FOOD: computer programs for calculating radiation dose to man from radionuclides in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Napier, B.A.; Roswell, R.L.; Kennedy, W.E. Jr.; Strenge, D.L.

    1980-06-01

    The computer programs ARRRG and FOOD were written to facilitate the calculation of internal radiation doses to man from the radionuclides in the environment and external radiation doses from radionuclides in the environment. Using ARRRG, radiation doses to man may be calculated for radionuclides released to bodies of water from which people might obtain fish, other aquatic foods, or drinking water, and in which they might fish, swim or boat. With the FOOD program, radiation doses to man may be calculated from deposition on farm or garden soil and crops during either an atmospheric or water release of radionuclides. Deposition may be either directly from the air or from irrigation water. Fifteen crop or animal product pathways may be chosen. ARRAG and FOOD doses may be calculated for either a maximum-exposed individual or for a population group. Doses calculated are a one-year dose and a committed dose from one year of exposure. The exposure is usually considered as chronic; however, equations are included to calculate dose and dose commitment from acute (one-time) exposure. The equations for calculating internal dose and dose commitment are derived from those given by the International Commission on Radiological Protection (ICRP) for body burdens and Maximum Permissible Concentration (MPC) of each radionuclide. The radiation doses from external exposure to contaminated farm fields or shorelines are calculated assuming an infinite flat plane source of radionuclides. A factor of two is included for surface roughness. A modifying factor to compensate for finite extent is included in the shoreline calculations.

  5. 目标反射环境红外辐射的模拟研究%Simulation of environment infrared radiation reflected by target

    Institute of Scientific and Technical Information of China (English)

    王雨飞; 李强; 廖胜

    2011-01-01

    When detecting extraatmospheric target based on IR radiation, the infrared radiation received by detector contains not only the target radiation, but also the reflection of environment source radiation, mainly the sun radiation, earth radiation and earth-reflection radiation. The simulation of target signature based on physical principle was performed. By calculating the position vector of sun, target, earth, observation station and the corresponding angles in the same reference frame at the given observation time, the sun radiation reflected by cylindrical target with solar battery plane was simulated. And the radiance of observation place of earth infrared radiation and earth -reflection reflected by target was calculated, using the improved random simulation method. At the end, spectral irradiance received by the detector at the given time was discussed by analyzing the simulation result, and the rule of total irradiance changing with orbit position change was given.%基于红外辐射探测大气层外目标时,探测器接收到的目标红外波段辐射不仅包含目标自身辐射,也包含对环境光源辐射的反射,主要为对太阳辐射、地球辐射、地球反照太阳辐射的反射.在按照基本物理原理进行建模的过程中,通过计算给定探测时间太阳、目标、地球以及观测站点在统一坐标系中位置矢量及其相应夹角,模拟了带太阳能帆板的圆柱主体目标反射的太阳辐射,并使用改进的随机模拟方法计算了地球红外辐射和地球反照经目标反射在探测位置的辐照度.最后,通过分析仿真结果,讨论了选定时间探测到的各辐射光谱辐照度,并给出其总辐照度随轨道位置的变化规律.

  6. Evaluation of Radiation Exposure to Staff and Environment Dose from [18F]-FDG in PET/CT and Cyclotron Center using Thermoluminescent Dosimetry

    Directory of Open Access Journals (Sweden)

    Zargan S.

    2017-03-01

    Full Text Available Background: PET/CT imaging using [18F]-FDG is utilized in clinical oncology for tumor detecting, staging and responding to therapy procedures. Essential consideration must be taken for radiation staff due to high gamma radiation in PET/CT and cyclotron center. The aim of this study was to assess the staff exposure regarding whole body and organ dose and to evaluate environment dose in PET/CT and cyclotron center. Materials and Methods: 80 patients participated in this study. Thermoluminescence, electronic personal dosimeter and Geiger–Muller dosimeter were also utilized for measurement purpose. Results: The mean annual equivalent organ dose for scanning operator with regard to lens of eyes, thyroid, breast and finger according to mean±SD value, were 0.262±0.044, 0.256±0.046, 0.257±0.040 and 0.316±0.118, respectively. The maximum and minimum estimated annual whole body doses were observed for injector and the chemist group with values of (3.98±0.021 mSv/yr and (1.64±0.014 mSv/yr, respectively. The observed dose rates were 5.67 µSv/h in uptake room at the distance of 0.5 meter from the patient whereas the value 4.94 and 3.08 µSv/h were recorded close to patient’s head in PET/CT room and 3.5 meter from the reception desk. Conclusion: In this study, the injector staff and scanning operator received the first high level and second high level of radiation. This study confirmed that low levels of radiation dose were received by all radiation staff during PET/CT procedure using 18F-FDG due to efficient shielding and using trained radiation staff in PET/CT and cyclotron center of Masih Daneshvari hospital.

  7. Evaluation of Radiation Exposure to Staff and Environment Dose from [18F]-FDG in PET/CT and Cyclotron Center using Thermoluminescent Dosimetry

    Science.gov (United States)

    Zargan, S.; Ghafarian, P.; Shabestani Monfared, A.; Sharafi, A.A.; Bakhshayeshkaram, M.; Ay, M.R.

    2017-01-01

    Background: PET/CT imaging using [18F]-FDG is utilized in clinical oncology for tumor detecting, staging and responding to therapy procedures. Essential consideration must be taken for radiation staff due to high gamma radiation in PET/CT and cyclotron center. The aim of this study was to assess the staff exposure regarding whole body and organ dose and to evaluate environment dose in PET/CT and cyclotron center. Materials and Methods: 80 patients participated in this study. Thermoluminescence, electronic personal dosimeter and Geiger-Muller dosimeter were also utilized for measurement purpose. Results: The mean annual equivalent organ dose for scanning operator with regard to lens of eyes, thyroid, breast and finger according to mean±SD value, were 0.262±0.044, 0.256±0.046, 0.257±0.040 and 0.316±0.118, respectively. The maximum and minimum estimated annual whole body doses were observed for injector and the chemist group with values of (3.98±0.021) mSv/yr and (1.64±0.014) mSv/yr, respectively. The observed dose rates were 5.67 µSv/h in uptake room at the distance of 0.5 meter from the patient whereas the value 4.94 and 3.08 µSv/h were recorded close to patient’s head in PET/CT room and 3.5 meter from the reception desk. Conclusion: In this study, the injector staff and scanning operator received the first high level and second high level of radiation. This study confirmed that low levels of radiation dose were received by all radiation staff during PET/CT procedure using 18F-FDG due to efficient shielding and using trained radiation staff in PET/CT and cyclotron center of Masih Daneshvari hospital. PMID:28451574

  8. On-line monitoring of base current and forward emitter current gain of the voltage regulator's serial pnp transistor in a radiation environment

    Directory of Open Access Journals (Sweden)

    Vukić Vladimir Đ.

    2012-01-01

    Full Text Available A method of on-line monitoring of the low-dropout voltage regulator's operation in a radiation environment is developed in this paper. The method had to enable detection of the circuit's degradation during exploitation, without terminating its operation in an ionizing radiation field. Moreover, it had to enable automatic measurement and data collection, as well as the detection of any considerable degradation, well before the monitored voltage regulator's malfunction. The principal parameters of the voltage regulator's operation that were monitored were the serial pnp transistor's base current and the forward emitter current gain. These parameters were procured indirectly, from the data on the voltage regulator's load and quiescent currents. Since the internal consumption current in moderately and heavily loaded devices was used, the quiescent current of a negligibly loaded voltage regulator of the same type served as a reference. Results acquired by on-line monitoring demonstrated marked agreement with the results acquired from examinations of the voltage regulator's maximum output current and minimum dropout voltage in a radiation environment. The results were particularly consistent in tests with heavily loaded devices. Results obtained for moderately loaded voltage regulators and the risks accompanying the application of the presented method, were also analyzed.

  9. Comparison of the space radiation environment at Foton M3 satellite altitudes and on aircraft altitudes for minimum of solar activity

    Science.gov (United States)

    Ploc, Ondrej; Dachev, Tsvetan; Spurny, Frantisek; Tomov, Borislav; Dimitrov, Plamen; Matviichuk, Yury; Bankov, Nikolay

    The space radiation environments at Foton M3 and aircraft altitudes were measured by using of practically equal silicon detector based on a deposited energy spectrometers in the fall of 2007. The aircraft measurements were performed on commercial flights of CSA airlines, while the Foton M3 measurements were inside of the ESA Biopan 6 experiment. Foton M3 orbit was close to circular between 260 and 289 km altitude and about 63° inclination. The relatively high inclination and small shielding of the detector (0.81 g/cm2 ) allow us to observe doses by electrons in the outer radiation belt as high as 2.3 mGy/hour. The comparison of the total GCR deposited doses for the Foton M3 time interval, which coincides with the absolute cycle 23 minimum of the solar activity is about 15% higher than the measured during the Foton M2 satellite doses in 2005. Comparisons of the latitudinal profiles for ISS in 2001, Foton 2 and 3 satellites and aircrafts show that the ratio of doses is as 1:2:3. Aircraft measurements are characterised through average values of exposure during frequent, statistically well based measurements on the routes Prague - New York. Dose absorbed in Si-detector per flight on these routes was about 8% higher in 2007 than in 2005. Different comparisons with the existing models for the radiation environment on aircraft and spacecraft altitudes are presented in the paper also and discussed.

  10. Modeling the effectiveness of shielding in the earth-moon-mars radiation environment using PREDICCS: five solar events in 2012

    Directory of Open Access Journals (Sweden)

    Quinn Philip R.

    2017-01-01

    Full Text Available Radiation in the form of solar energetic particles (SEPs presents a severe risk to the short-term health of astronauts and the success of human exploration missions beyond Earth’s protective shielding. Modeling how shielding mitigates the dose accumulated by astronauts is an essential step toward reducing these risks. PREDICCS (Predictions of radiation from REleASE, EMMREM, and Data Incorporating the CRaTER, COSTEP, and other SEP measurements is an online tool for the near real-time prediction of radiation exposure at Earth, the Moon, and Mars behind various levels of shielding. We compare shielded dose rates from PREDICCS with dose rates from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER onboard the Lunar Reconnaissance Orbiter (LRO at the Moon and from the Radiation Assessment Detector (RAD on the Mars Science Laboratory (MSL during its cruise phase to Mars for five solar events in 2012 when Earth, MSL, and Mars were magnetically well connected. Calculations of the accumulated dose demonstrate a reasonable agreement between PREDICCS and RAD ranging from as little as 2% difference to 54%. We determine mathematical relationships between shielding levels and accumulated dose. Lastly, the gradient of accumulated dose between Earth and Mars shows that for the largest of the five solar events, lunar missions require aluminum shielding between 1.0 g cm−2 and 5.0 g cm−2 to prevent radiation exposure from exceeding the 30-day limits for lens and skin. The limits were not exceeded near Mars.

  11. A system for protecting the environment from ionising radiation. Selecting reference fauna and flora, and the possible dose models and environmental geometries that could be applied to them

    Energy Technology Data Exchange (ETDEWEB)

    Pentreath, R.J. [Environmental Systems Science Centre, University of Reading, Whiteknights, P.O. Box 227, RG6 6AB Reading (United Kingdom); Woodhead, D.S. [Centre for Environment, Fisheries and Aquaculture Science, CEFAS Lowestoft Laboratory, Pakefield Road, Suffolk NR33 0HT Lowestoft (United Kingdom)

    2001-09-28

    In order to demonstrate, explicitly, that the environment can be protected with respect to controlled sources of ionising radiation, it is essential to have a systematic framework within which dosimetry models for fauna and flora can be used. And because of the practical limitations on what could reasonably be modelled and the amount of information that could reasonably be obtained, it is also necessary to limit the application of such models to a 'set' of fauna and flora within a 'reference' context. This paper, therefore, outlines the factors that will need to be considered to select such 'reference' fauna and flora, and describes some of the factors and constraints necessary to develop the associated dosimetry models. It also describes some of the most basic environmental geometries within which the dose models could be set in order to make comparisons amongst different radiation sources.

  12. High levels of interspecific gene flow in an endemic cichlid fish adaptive radiation from an extreme lake environment.

    Science.gov (United States)

    Ford, Antonia G P; Dasmahapatra, Kanchon K; Rüber, Lukas; Gharbi, Karim; Cezard, Timothee; Day, Julia J

    2015-07-01

    Studying recent adaptive radiations in isolated insular systems avoids complicating causal events and thus may offer clearer insight into mechanisms generating biological diversity. Here, we investigate evolutionary relationships and genomic differentiation within the recent radiation of Alcolapia cichlid fish that exhibit extensive phenotypic diversification, and which are confined to the extreme soda lakes Magadi and Natron in East Africa. We generated an extensive RAD data set of 96 individuals from multiple sampling sites and found evidence for genetic admixture between species within Lake Natron, with the highest levels of admixture between sympatric populations of the most recently diverged species. Despite considerable environmental separation, populations within Lake Natron do not exhibit isolation by distance, indicating panmixia within the lake, although individuals within lineages clustered by population in phylogenomic analysis. Our results indicate exceptionally low genetic differentiation across the radiation despite considerable phenotypic trophic variation, supporting previous findings from smaller data sets; however, with the increased power of densely sampled SNPs, we identify genomic peaks of differentiation (FST outliers) between Alcolapia species. While evidence of ongoing gene flow and interspecies hybridization in certain populations suggests that Alcolapia species are incompletely reproductively isolated, the identification of outlier SNPs under diversifying selection indicates the radiation is undergoing adaptive divergence.

  13. RESULTS OF RADIATION-HYGIENIC MONITORING OF THE BASIC PARAMETERS OF THE HUMAN ENVIRONMENT IN THE KIROV REGION

    Directory of Open Access Journals (Sweden)

    B. N. Skolotnev

    2012-01-01

    Full Text Available The paper describes the experience of the laboratory of radiation monitoring in the the Kirov region since 1963. The results of long-term measurements of the environmental objects are presented. Gamma background measurement and investigation of radionuclides’ content in depositions are compared as methods for radioactive contamination assessment.

  14. [Radiation ecological environment in the Republic of Kazakhstan in the vicinity of the reactors and on the territory of the Semipalatinsk Test Site].

    Science.gov (United States)

    Kim, D S

    2012-01-01

    The results of research into the environmental conditions in the regions of location of the pressurized water reactor WWR-K, fast neutron breeder BN-350 and on the territory of the Semipalatinsk Test Site are represented. The effects of the exposure to aerosol emissions from WWR-K and BN-350 reactors on the environment are summarized. We present some arguments in favor of the safe operation of fission reactors in compliance with the rules and norms of nuclear and radiation protection and the efficient disposal of radioactive waste on the territory of the Republic.

  15. P-stop isolation study of irradiated n-in-p type silicon strip sensors for harsh radiation environments

    Science.gov (United States)

    Printz, Martin

    2016-09-01

    In order to determine the most radiation hard silicon sensors for the CMS Experiment after the Phase II Upgrade in 2023 a comprehensive study of silicon sensors after a fluence of up to 1.5 ×1015neq /cm2 corresponding to 3000fb-1 after the HL-LHC era has been carried out. The results led to the decision that the future Outer Tracker (20 cm MIPs penetrating the sensor between two strips.

  16. Effects of gamma radiation on chlorophyll content of Cladonia verticillaris (Raddi) Fr. (lichen) collected in different environments

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Helena P. de B.; Martins, Monica C.B.; Pereira, Eugenia C.; Barbosa, Clarissa R.; Silva, Nicacio; Franca, Andre Luiz Teixeira de; Colaco, Waldeciro, E-mail: barrosleny@hotmail.com, E-mail: monicabarmartins@hotmail.com, E-mail: verticillaris@gmail.com, E-mail: lissa_fer@hotmail.com, E-mail: nhsilva@uol.com.br, E-mail: wcolaco@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Maciel, Leonardo N. de Q., E-mail: lenoquema@yahoo.com.br [Instituto Federal de Educacao Ciencia e Tecnologia de Pernambuco (IFPE), Vitoria de Santo Antao, PE (Brazil)

    2013-07-01

    Lichens are formed by symbiosis between a fungus (mycobiont) and an alga (photobiont, chloroficeae and or cyanobacteria). The radiosensitivity in lichens is not in proportion to the symbiotic organisms, and the algae layer is more radiosensitive than the fungi. Thus, in order check to algae radiosensitivity, sought to quantify the levels of chlorophyll from C. verticillaris samples with different doses of gamma radiation, since the amount of this pigment is closely related to the percentage of living algal cells. Lichen samples were collected in Saloa-PE and Alhandra- PE, sites that have similar physiognomic characteristics, but with different altitudes. C. verticillaris samples (12 g) of both sampling sites were subjected to gamma irradiator (Co{sup 60} - irradiator, Gammacell 200 Excel, dose rates 7.795 kGy) at 0, 10, 50, 100, 500, 1.000, 5.000 and 10.000 Gy. Lichens samples were collected (1.5 g) and stored separately for further analysis. The results indicated that the total production of chlorophyll in all samples exposed to gamma radiation was lower than non-irradiated samples, demonstrating that way that gamma radiation causes likely to damage/changes in physiological characteristics C. verticillaris. (author)

  17. Evaluation of test structures for the novel n{sup +}-in-p pixel and strip sensors for very high radiation environments

    Energy Technology Data Exchange (ETDEWEB)

    Unno, Y., E-mail: yoshinobu.unno@kek.jp [Institute of Particle and Nuclear Study, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba-shi 305-0801 (Japan); The Graduate University for Advanced Studies (SOKENDAI), 1-1 Oho, Tsukuba-shi 305-0801 (Japan); Mitsui, S. [The Graduate University for Advanced Studies (SOKENDAI), 1-1 Oho, Tsukuba-shi 305-0801 (Japan); Hori, R.; Ikegami, Y.; Terada, S. [Institute of Particle and Nuclear Study, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba-shi 305-0801 (Japan); Kamada, S.; Yamamura, K. [Solid-state Division, Hamamatsu Photonics K.K., 1126-1 Ichino-cho, Higashi-ku, Hamamatsu-shi 435-8558 (Japan); Hanagaki, K. [Department of Physics, Osaka University, Machikaneyama-cho, Toyonaka-shi, Osaka 560-0043 (Japan); Hara, K. [Institute of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba-shi 305-8571 (Japan); Jinnouchi, O. [Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Kimura, N. [Research Institute for Science and Engineering, Waseda University, 1-6-1 Nishi-Waseda, Shinjuku-ku, Tokyo 169-8050 (Japan); Nagai, K. [Institute of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba-shi 305-8571 (Japan); Nakano, I. [Department of Physics, Okayama University, 3-1-1 Tshushima-naka, Kita-ku, Okayama-shi 700-8530 (Japan); Oda, S. [Department of Physics, Kyushu University, 6-10-11 Hakozaki, Higashi-ku, Fukuoka-shi 812-8581 (Japan); Takashima, R. [Department of Education, Kyoto University of Education, 1 Fukakusa-Fujimori-cho, Fushimi-ku, Kyoto 612-8522 (Japan); Takubo, Y. [Institute of Particle and Nuclear Study, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba-shi 305-0801 (Japan); Tojo, J. [Department of Physics, Kyushu University, 6-10-11 Hakozaki, Higashi-ku, Fukuoka-shi 812-8581 (Japan); and others

    2013-12-11

    Radiation-tolerant n{sup +}-in-p silicon sensors were developed for use in very high radiation environments. Novel n{sup +}-in-p silicon strip and pixel sensors and test structures were fabricated, tested and evaluated, in order to understand the designs implemented. The resistance between the n{sup +} implants (interstrip resistance), the electric potential of the p-stop, and the punch-through-protection (PTP) onset voltage were measured before and as a function of fluence after irradiation. The technology computer-aided design (TCAD) simulations were used to understand the radiation damage and fluence dependence of the structures. The decrease in the interstrip resistance is a consequence of increased leakage current. The decrease in the electric potential of the p-stop results from a build-up of positive charge in the silicon–silicon oxide interface. The decrease and subsequent increase in the PTP onset voltages results from the interface charge build-up and an increase in acceptor states.

  18. Radiation Chemistry

    Science.gov (United States)

    Wojnárovits, L.

    Ionizing radiation causes chemical changes in the molecules of the interacting medium. The initial molecules change to new molecules, resulting in changes of the physical, chemical, and eventually biological properties of the material. For instance, water decomposes to its elements H2 and O2. In polymers, degradation and crosslinking take place. In biopolymers, e.g., DNS strand breaks and other alterations occur. Such changes are to be avoided in some cases (radiation protection), however, in other cases they are used for technological purposes (radiation processing). This chapter introduces radiation chemistry by discussing the sources of ionizing radiation (radionuclide sources, machine sources), absorption of radiation energy, techniques used in radiation chemistry research, and methods of absorbed energy (absorbed dose) measurements. Radiation chemistry of different classes of inorganic (water and aqueous solutions, inorganic solids, ionic liquids (ILs)) and organic substances (hydrocarbons, halogenated compounds, polymers, and biomolecules) is discussed in concise form together with theoretical and experimental backgrounds. An essential part of the chapter is the introduction of radiation processing technologies in the fields of polymer chemistry, food processing, and sterilization. The application of radiation chemistry to nuclear technology and to protection of environment (flue gas treatment, wastewater treatment) is also discussed.

  19. Thermal Radiometer Signal Processing Using Radiation Hard CMOS Application Specific Integrated Circuits for Use in Harsh Planetary Environments

    Science.gov (United States)

    Quilligan, G.; DuMonthier, J.; Aslam, S.; Lakew, B.; Kleyner, I.; Katz, R.

    2015-01-01

    Thermal radiometers such as proposed for the Europa Clipper flyby mission require low noise signal processing for thermal imaging with immunity to Total Ionizing Dose (TID) and Single Event Latchup (SEL). Described is a second generation Multi- Channel Digitizer (MCD2G) Application Specific Integrated Circuit (ASIC) that accurately digitizes up to 40 thermopile pixels with greater than 50 Mrad (Si) immunity TID and 174 MeV-sq cm/mg SEL. The MCD2G ASIC uses Radiation Hardened By Design (RHBD) techniques with a 180 nm CMOS process node.

  20. P-stop isolation study of irradiated n-in-p type silicon strip sensors for harsh radiation environment

    CERN Document Server

    AUTHOR|(CDS)2084505

    2015-01-01

    In order to determine the most radiation hard silicon sensors for the CMS Experiment after the Phase II Upgrade in 2023 a comprehensive study of silicon sensors after a fluence of up to $1.5\\times10^{15} n_{eq}/cm^{2}$ corresponding to $3000 fb^{-1}$ after the HL-LHC era has been carried out. The results led to the decision that the future Outer Tracker (20~cm${<}R{<}$110~cm) of CMS will consist of n-in-p type sensors. This technology is more radiation hard but also the manufacturing is more challenging compared to p-in-n type sensors due to additional process steps in order to suppress the accumulation of electrons between the readout strips. One possible isolation technique of adjacent strips is the p-stop structure which is a p-type material implantation with a certain pattern for each individual strip. However, electrical breakdown and charge collection studies indicate that the process parameters of the p-stop structure have to be carefully calibrated in order to achieve a sufficient strip isolatio...

  1. Soil water effect on crop growth, leaf gas exchange, water and radiation use efficiency of Saccharum spontaneum L. ssp. aegyptiacum (Willd. Hackel in semi-arid Mediterranean environment

    Directory of Open Access Journals (Sweden)

    Danilo Scordia

    2015-12-01

    Full Text Available Great effort has been placed to identify the most suited bioenergy crop under different environments and management practices, however, there is still need to find new genetic resources for constrained areas. For instance, South Mediterranean area is strongly affected by prolonged drought, high vapour pressure deficit (VPD and extremely high temperatures during summertime. In the present work we investigated the soil water effect on crop growth and leaf gas exchange of Saccharum spontaneum L. ssp. aegyptiacum (Willd. Hackel, a perennial, rhizomatous, herbaceous grass. Furthermore, the net increase of biomass production per unit light intercepted [radiation use efficiency (RUE] and per unit water transpired [water use efficiency (WUE] was also studied. To this end a field trial was carried out imposing three levels of soil water availability (I100, I50 and I0, corresponding to 100%, 50% and 0% of ETm restutition under a semi-arid Mediterranean environment. Leaf area index (LAI, stem height, biomass dry matter yield, CO2 assimilation rate, and transpiration rate resulted significantly affected by measurement time and irrigation treatment, with the highest values in I100 and the lowest in I0. RUE was the highest in I100 followed by I50 and I0; on the other hand, WUE was higher in I0 than I50 and I100. At LAI values greater than 2.0, 85% photosynthetically active radiation was intercepted by the Saccharum stand, irrespective of the irrigation treatment. Saccharum spontaneum spp. aegyptiacum is a potential species for biomass production in environment characterized by drought stress, high temperatures and high VPD, as those of Southern Europe and similar semi-arid areas.

  2. A long-term study of new particle formation in a coastal environment: Meteorology, gas phase and solar radiation implications

    Energy Technology Data Exchange (ETDEWEB)

    Sorribas, M., E-mail: sorribas@ugr.es [Department of Applied Physics, University of Granada, Granada, 18071 (Spain); Andalusian Institute for Earth System Research (IISTA), University of Granada, 18006 (Spain); Adame, J.A. [‘El Arenosillo’ — Atmospheric Sounding Station, Atmospheric Research and Instrumentation Branch, National Institute for Aerospace Technology (INTA), Mazagón, Huelva, 21130 (Spain); Olmo, F.J. [Department of Applied Physics, University of Granada, Granada, 18071 (Spain); Andalusian Institute for Earth System Research (IISTA), University of Granada, 18006 (Spain); Vilaplana, J.M.; Gil-Ojeda, M. [‘El Arenosillo’ — Atmospheric Sounding Station, Atmospheric Research and Instrumentation Branch, National Institute for Aerospace Technology (INTA), Mazagón, Huelva, 21130 (Spain); Alados-Arboledas, L. [Department of Applied Physics, University of Granada, Granada, 18071 (Spain); Andalusian Institute for Earth System Research (IISTA), University of Granada, 18006 (Spain)

    2015-04-01

    New particle formation (NPF) was investigated at a coastal background site in Southwest Spain over a four-year period using a Scanning Particle Mobility Sizer (SMPS). The goals of the study were to characterise the NPF and to investigate their relationship to meteorology, gas phase (O{sub 3}, SO{sub 2}, CO and NO{sub 2}) and solar radiation (UVA, UVB and global). A methodology for identifying and classifying the NPF was implemented using the wind direction and modal concentrations as inputs. NPF events showed a frequency of 24% of the total days analysed. The mean duration was 9.2 ± 4.2 h. Contrary to previous studies conducted in other locations, the NPF frequency reached its maximum during cold seasons for approximately 30% of the days. The lowest frequency took place in July with 10%, and the seasonal wind pattern was found to be the most important parameter influencing the NPF frequency. The mean formation rate was 2.2 ± 1.7 cm{sup −3} s{sup −1}, with a maximum in the spring and early autumn and a minimum during the summer and winter. The mean growth rate was 3.8 ± 2.4 nm h{sup −1} with higher values occurring from spring to autumn. The mean and seasonal formation and growth rates are in agreement with previous observations from continental sites in the Northern Hemisphere. NPF classification of different classes was conducted to explore the effect of synoptic and regional-scale patterns on NPF and growth. The results show that under a breeze regime, the temperature indirectly affects NPF events. Higher temperatures increase the strength of the breeze recirculation, favouring gas accumulation and subsequent NPF appearance. Additionally, the role of high relative humidity in inhibiting the NPF was evinced during synoptic scenarios. The remaining meteorological variables (RH), trace gases (CO and NO), solar radiation, PM{sub 10} and condensation sink, showed a moderate or high connection with both formation and growth rates. - Highlights: • New

  3. Response of neutron dosemeters in radiation protection environments: an investigation of techniques to improve estimates of dose equivalent

    Energy Technology Data Exchange (ETDEWEB)

    Naismith, O.F.; Thomas, D.J. [National Physical Lab., Teddington (United Kingdom); Siebert, B.R.L. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

    1997-09-01

    The response of practicable neutron dosemeters for routine use generally does not match the conversion function from fluence for radiation protection quantities such as the ambient dose equivalent. As a consequence, significant errors may be encountered when monitoring in a neutron energy spectrum different from that in which the dosemeter was calibrated, which is almost inevitably the case. A database of neutron energy spectra, detector response functions, and dosimetric conversion factors has been developed, and has been used to investigate the extent of this problem. The paper examines various ways of improving dosemeter response by `ranking` spectra and deriving correction factors based upon this ordering. In the case of area monitoring, a combination of two responses (e.g. a rem meter and TEPC) may serve to improve the measurement of dose equivalent. (author).

  4. Proceedings of the Fiber Optics in the Nuclear Environment Symposium 25-27 March 1980. Volume II. Radiation Physics,

    Science.gov (United States)

    1980-04-30

    Alcaraz, Ernest (JAYCOR) Davis, William ( Sperry Univac) Alfonte, William (GE -TEMPO) Dawson, Larry (SLA) Allas, Richard (NRL) DeKalb, Richard (3MD...James (LMSC) Rogers , Samuel (RDA) Knowles, C.P. (DNA) Rosado, John (IIDL) Kochanski, R. (NOSC) Sandoval, Liberato (EG4*G) Kronenberg, Stanley (ET&iDL...NS/410 P. Lyons ATM: C. Rogers ATTN: C. MacDonald Lovelace iomed. 4 Environ. Rsc. Inst., Inc. ATIN: W. Grahem, Jr. AIIM: R. Fletcher Rockwell

  5. A survey of sources of incoherent artificial optical radiation in a hospital environment in accordance with European Directive 2006/25/EC: evaluation of the related exposure risk.

    Science.gov (United States)

    Cavatorta, Claudia; Lualdi, Manuela; Meroni, Silvia; Polita, Giovanni; Bolchi, Mauro; Pignoli, Emanuele

    2016-03-01

    The evaluation of incoherent artificial optical radiation (AOR) exposure in hospital environments is a complex task due to the variety of sources available. This study has been designed to provide a proposal for the precautionary assessment of the related risk. This survey suggested that, in our Institution, at least three kinds of AOR sources required specific investigations: ambient lighting, theatre operating lighting and ultraviolet radiation (UVR) sources. For each kind of evaluated sources a specific measurement approach was developed. All irradiance measurements were made using a commercial spectroradiometer. The obtained results were compared with the appropriate exposure limit values (ELVs) defined in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines and adopted by the European Directive 2006/25/EC. The risk related to the evaluated AOR exposure was finally assessed according to our risk matrix. According to our results, the emission of ambient lighting in the actual exposure conditions was always in accordance with the ELVs and the related risk was classifiable as not relevant. The risk related to the exposure to theatre operating lighting resulted not negligible, especially when two or more sources were used with focal spots overlapping on reflective objects. UVR sources emission may represent a health hazard depending, in particular, on the set up of the device containing the source. In case of laminar flow cabinets and closed transilluminators, if the UVR source is well contained within an enclosure with interlock, it presents no risk of exposure. Otherwise, the emission arising from UVR lamps, open transilluminators or sources not provided with interlock, may represent a risk classifiable as high even in the actual working conditions. The personal protective equipment used by workers were also assessed and their suitability was discussed.

  6. Development of the control system of the ALICE transition radiation detector and of a test environment for quality-assurance of its front-end electronics

    Energy Technology Data Exchange (ETDEWEB)

    Mercado Perez, Jorge

    2008-11-10

    Within this thesis, the detector control system (DCS) for the Transition Radiation Detector (TRD) of the ALICE experiment at the Large Hadron Collider has been developed. The TRD DCS is fully implemented as a detector oriented hierarchy of objects behaving as finite state machines. It controls and monitors over 65 thousand front-end electronics (FEE) units, a few hundred low voltage and one thousand high voltage channels, and other sub-systems such as cooling and gas. Commissioning of the TRD DCS took place during several runs with ALICE using cosmic events. Another part of this thesis describes the development of a test environment for large-scale production quality-assurance of over 4 thousand FEE read-out boards containing in total about 1.2 million read-out channels. The hardware and software components are described in detail. Additionally, a series of performance studies were carried out earlier including radiation tolerance tests of the TRAP chip which is the core component of the TRD FEE. (orig.)

  7. A Comparison of Van Allen Belt Radiation Environment Modeling Programs: AE8/AP8 Legacy, AE9/AP9, and SPENVIS

    Science.gov (United States)

    Reed, Evan; Pellish, Jonathan

    2016-01-01

    In the space surrounding Earth there exists an active radiation environment consisting mostly of electrons and protons that have been trapped by Earths magnetic field. This radiation, also known as the Van Allen Belts, has the potential to damage man-made satellites in orbit; thus, proper precautions must be taken to shield NASA assets from this phenomenon. Data on the Van Allen Belts has been collected continuously by a multitude of space-based instruments since the beginning of space exploration. Subsequently, using theory to fill in the gaps in the collected data, computer models have been developed that take in the orbital information of a hypothetical mission and output the expected particle fluence and flux for that orbit. However, as new versions of the modeling system are released, users are left wondering how the new version differs from the old. Therefore, we performed a comparison of three different editions of the modeling system: AE8/AP8 (legacy), which is included in the model 9 graphical user interface as an option for ones calculations, AE9/AP9, and the Space Environment Information System (SPENVIS), which is an online-based form of AE8/AP8 developed by NASA and the European Space Agency that changed the code to allow the program to extrapolate data to predict fluence and flux at higher energies. Although this evaluation is still ongoing, it is predicted that the model 8 (legacy) and SPENVIS version will have identical outputs with the exception of the extended energy levels from SPENVIS, while model 9 will provide different fluences than model 8 based on additional magnetic field descriptions and on-orbit data.

  8. Radiation protection research projects. Program report 2014. Report on research program radiation protection of the Federal ministry for environment, nature conservation and reactor safety with technical and administrative steering by the Bundesamt fuer Strahlenschutz; Strahlenschutzforschung. Programmreport 2014. Bericht ueber das vom Bundesamt fuer Strahlenschutz fachlich begleitete und administrativ umgesetzte Forschungsprogramm Strahlenschutz des Bundesministeriums fuer Umwelt, Naturschutz, Bau und Reaktorsicherheit

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt-Hannig, Annemarie; Loebke-Reinl, Angelika; Peter, Josef; Goedde, Ralph; Hachenberger, Claudia; Trugenberger-Schnabel, Angela

    2015-09-15

    On behalf of the Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB) the Federal Office for Radiation Protection (BfS) awards research grants for projects in the field of radiation protection. The findings of these projects se rve as decision aiding information in the development of radiation protection regulations as well as in the fulfilment of specific tasks in the field of radiation protection. The tasks of the Federal Office for Radiation Protection involve planning, technical and administrative preparation, awarding of contracts, general support as well as the technical evaluation of research and study projects. This report provides information on results, i.e. preliminary (in the form of status reports) and, where applicable, final results of radiation protection projects within the BMUB's Environmental Research Plan for the year 2014.

  9. Interactive Effects of Temperature and UV Radiation on Photosynthesis of Chlorella Strains from Polar, Temperate and Tropical Environments: Differential Impacts on Damage and Repair.

    Science.gov (United States)

    Wong, Chiew-Yen; Teoh, Ming-Li; Phang, Siew-Moi; Lim, Phaik-Eem; Beardall, John

    2015-01-01

    Global warming and ozone depletion, and the resulting increase of ultraviolet radiation (UVR), have far-reaching impacts on biota, especially affecting the algae that form the basis of the food webs in aquatic ecosystems. The aim of the present study was to investigate the interactive effects of temperature and UVR by comparing the photosynthetic responses of similar taxa of Chlorella from Antarctic (Chlorella UMACC 237), temperate (Chlorella vulgaris UMACC 248) and tropical (Chlorella vulgaris UMACC 001) environments. The cultures were exposed to three different treatments: photosynthetically active radiation (PAR; 400-700 nm), PAR plus ultraviolet-A (320-400 nm) radiation (PAR + UV-A) and PAR plus UV-A and ultraviolet-B (280-320 nm) radiation (PAR + UV-A + UV-B) for one hour in incubators set at different temperatures. The Antarctic Chlorella was exposed to 4, 14 and 20°C. The temperate Chlorella was exposed to 11, 18 and 25°C while the tropical Chlorella was exposed to 24, 28 and 30°C. A pulse-amplitude modulated (PAM) fluorometer was used to assess the photosynthetic response of microalgae. Parameters such as the photoadaptive index (Ek) and light harvesting efficiency (α) were determined from rapid light curves. The damage (k) and repair (r) rates were calculated from the decrease in ΦPSIIeff over time during exposure response curves where cells were exposed to the various combinations of PAR and UVR, and fitting the data to the Kok model. The results showed that UV-A caused much lower inhibition than UV-B in photosynthesis in all Chlorella isolates. The three isolates of Chlorella from different regions showed different trends in their photosynthesis responses under the combined effects of UVR (PAR + UV-A + UV-B) and temperature. In accordance with the noted strain-specific characteristics, we can conclude that the repair (r) mechanisms at higher temperatures were not sufficient to overcome damage caused by UVR in the Antarctic Chlorella strain

  10. 高稳晶振在空间辐照条件下的频率特性变化%The Frequency Characteristic of High Stability Crystal Under Space Radiation Environment

    Institute of Scientific and Technical Information of China (English)

    阎栋梁; 韩红; 杨曦

    2012-01-01

    在空间恶劣环境下要求星载高稳晶振正常有效地工作,需要对其在空间辐照环境下的频率特性变化进行研究,利用地面辐照设备模拟空间辐照环境,通过不断增加辐照剂量,研究晶振相位噪声、短期频率稳定度、谐杂波以及输出功率等特性.%In order to insure the high stability crystal on satellite to work normally, the change of frequency character needs to be researched under space radiation environment, using ground radiation device to simulate space radiation environment, and phase noise, short term frequency stability, harmonics, spurious and output power also need to be researched.

  11. Implementation of the procedure of high radiation of the forum about radiological protection in the health care environment; Implantacion del procedimiento de alta radiologica del foro sobre proteccion radiologica en el medio sanitario

    Energy Technology Data Exchange (ETDEWEB)

    Castro Novais, J.; Pardo Perez, E.; Molina Lopez, M. Y.; Ruiz Maqueda, S.; Maldonado Suarez, A.

    2013-07-01

    The objective of this work is to present the results of the implementation in our hospital the procedure of high radiological in patients treated with 131 I described in the document presented by the Forum on Radiation Protection in the Health Environment formed by the Consejo de Seguridad Nuclear and the Spanish societies of Fisica Medica and Proteccion Radiologica. (Author)

  12. Adaptation of photosynthesis in marama bean Tylosema esculentum (Burchell A. Schreiber) to a high temperature, high radiation, drought-prone environment.

    Science.gov (United States)

    Mitchell, R A C; Keys, A J; Madgwick, P J; Parry, M A J; Lawlor, D W

    2005-01-01

    Marama bean, Tylosema esculentum, is a tuberous legume native to the Kalahari region of Southern Africa where it grows under high temperatures (typical daily max 37 degrees C during growing season) and radiation (frequently in excess of 2000 micromol m(-2) s(-1)) in sandy soils with low rainfall. These conditions might be expected to select for increased water-use efficiency of photosynthesis. However, marama was found to give similar leaf photosynthetic rates to other C3 plants for a given internal leaf CO2 concentration and Rubisco content. Under conditions of increasing drought, no increase in water-use efficiency of photosynthesis was observed, but stomata closed early and preceded any change in leaf water potential. The possibility of subtle adaptations of photosynthetic characteristics to its natural environment were investigated at the level of Rubisco kinetics. The specificity factor of marama Rubisco was slightly lower than that of wheat, but the apparent Km for CO2 in air (Km') was about 20% lower than that of wheat. This is consistent with better adaptation for efficient photosynthesis at high temperatures in marama compared to wheat, although the net benefit is predicted to be very small (marama rbcL gene shows 27 deduced amino acid residue differences from that for wheat, and the possibility that one or more of these cause the difference in Rubisco Km' is discussed.

  13. Severe signal loss in diamond beam loss monitors in high particle rate environments by charge trapping in radiation-induced defects

    Energy Technology Data Exchange (ETDEWEB)

    Kassel, Florian; Boer, Wim de [Institute for Experimental Nuclear Physics (IEKP), KIT, Karlsruhe (Germany); Guthoff, Moritz; Dabrowski, Anne [CERN, Meyrin (Switzerland)

    2016-10-15

    The beam condition monitoring leakage (BCML) system is a beam monitoring device in the compact muon solenoid (CMS) experiment at the large hadron collider (LHC). As detectors 32 poly-crystalline (pCVD) diamond sensors are positioned in rings around the beam pipe. Here, high particle rates occur from the colliding beams scattering particles outside the beam pipe. These particles cause defects, which act as traps for the ionization, thus reducing the charge collection efficiency (CCE). However, the loss in CCE was much more severe than expected from low rate laboratory measurements and simulations, especially in single-crystalline (sCVD) diamonds, which have a low initial concentration of defects. After an integrated luminosity of a few fb{sup -1} corresponding to a few weeks of LHC operation, the CCE of the sCVD diamonds dropped by a factor of five or more and quickly approached the poor CCE of pCVD diamonds. The reason why in real experiments the CCE is much worse than in laboratory experiments is related to the ionization rate. At high particle rates the trapping rate of the ionization is so high compared with the detrapping rate, that space charge builds up. This space charge reduces locally the internal electric field, which in turn increases the trapping rate and recombination and hence reduces the CCE in a strongly non-linear way. A diamond irradiation campaign was started to investigate the rate-dependent electrical field deformation with respect to the radiation damage. Besides the electrical field measurements via the transient current technique (TCT), the CCE was measured. The experimental results were used to create an effective deep trap model that takes the radiation damage into account. Using this trap model, the rate-dependent electrical field deformation and the CCE were simulated with the software SILVACO TCAD. The simulation, tuned to rate-dependent measurements from a strong radioactive source, was able to predict the non-linear decrease of the

  14. How injurious to health is ionizing radiation. General overview and medical assessment with special regard to environment exposure by radon. Wie gesundheitsgefaehrdend ist ionisierende Strahlung. Allgemeiner Ueberblick und strahlenschutzmedizinische Bewertung unter besonderer Beruecksichtigung der Umweltbelastung durch Radon

    Energy Technology Data Exchange (ETDEWEB)

    Arndt, D. (Staatliches Amt fuer Atomsicherheit und Strahlenschutz, Berlin (Germany, F.R.). Abt. Strahlenschutzmedizin)

    1990-10-01

    Basing on data and well-known facts a general overview is given about the danger of ionizing radiation to the health of man. It is the concern of this enlightening article to make an objective assessment of this noxa in its dose-effect-relation with special regard to the questions of environment exposure, as to be found for example in the uran mining area of the ore mountains, where at present a considerable radiophobie of the population can be observed. (orig.).

  15. Rapid Development of the Radiation Curing Sector

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Radiation curing is an advanced material surface treatment technology using ultraviolet (UV) radiation and electronic beams (EB). With the greater attention paid to environ mentel protection in recent years ,radiation curing has developed rapidly.

  16. ANFIS, SVM and ANN soft-computing techniques to estimate daily global solar radiation in a warm sub-humid environment

    Science.gov (United States)

    Quej, Victor H.; Almorox, Javier; Arnaldo, Javier A.; Saito, Laurel

    2017-03-01

    Daily solar radiation is an important variable in many models. In this paper, the accuracy and performance of three soft computing techniques (i.e., adaptive neuro-fuzzy inference system (ANFIS), artificial neural network (ANN) and support vector machine (SVM) were assessed for predicting daily horizontal global solar radiation from measured meteorological variables in the Yucatán Peninsula, México. Model performance was assessed with statistical indicators such as root mean squared error (RMSE), mean absolute error (MAE) and coefficient of determination (R2). The performance assessment indicates that the SVM technique with requirements of daily maximum and minimum air temperature, extraterrestrial solar radiation and rainfall has better performance than the other techniques and may be a promising alternative to the usual approaches for predicting solar radiation.

  17. Management of ionizing radiation sources in university, medical and industrial environments; Gestion des sources ionisantes en milieux universitaire, medical et industriel

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    This conference treats several subjects relative to the use of radioactive sources. The first session comprises three articles about ionizing sources and regulation. The second session, with three articles, tackles the question of radiation protection in the use of sources in industrial field. The third session, four articles, treats the same question but in the medicine and university media. The fourth session (three articles) is devoted to the organisation of radiation protection in the case of accidents. The fifth session concerns the management of spent sources (three articles). The sixth session studies the radiation protection of sources in Europe. The seventh and final session ends with the part and coordination of actors in radiation protection in the sources management (three articles). (N.C.)

  18. RHOBOT: Radiation hardened robotics

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, P.C.; Posey, L.D. [Sandia National Labs., Albuquerque, NM (United States)

    1997-10-01

    A survey of robotic applications in radioactive environments has been conducted, and analysis of robotic system components and their response to the varying types and strengths of radiation has been completed. Two specific robotic systems for accident recovery and nuclear fuel movement have been analyzed in detail for radiation hardness. Finally, a general design approach for radiation-hardened robotics systems has been developed and is presented. This report completes this project which was funded under the Laboratory Directed Research and Development program.

  19. Radiation Protection

    Science.gov (United States)

    ... EPA United States Environmental Protection Agency Search Search Radiation Protection Share Facebook Twitter Google+ Pinterest Contact Us Radiation Protection Document Library View and download EPA radiation ...

  20. Radiation Therapy

    Science.gov (United States)

    ... the area is stitched shut. Another treatment, called proton-beam radiation therapy , focuses the radiation on the ... after radiation treatment ends. Sore mouth and tooth decay. If you received radiation therapy to the head ...

  1. Radiation sickness

    Science.gov (United States)

    ... radiation. There are two basic types of radiation: ionizing and nonionizing. Nonionizing radiation comes in the form of light, radio waves, microwaves and radar. This kind of radiation usually ...

  2. Radiation dosimetry.

    OpenAIRE

    Cameron, J

    1991-01-01

    This article summarizes the basic facts about the measurement of ionizing radiation, usually referred to as radiation dosimetry. The article defines the common radiation quantities and units; gives typical levels of natural radiation and medical exposures; and describes the most important biological effects of radiation and the methods used to measure radiation. Finally, a proposal is made for a new radiation risk unit to make radiation risks more understandable to nonspecialists.

  3. Radiation hormesis in plant

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Sung; Song, Hi Sup; Lee, Young Keun; Lee, Byung Hun; Shin, In Chul; Lim, Young Taek

    2000-04-01

    This research was performed to investigate the effects of low dose {gamma}-ray radiation on the seed germination and the following physiological responses in vegetable crops. Special attention was focused on whether the resistance of vegetables against the unfavorable conditions of environment such as subsequent high doses of radiation or Phytophthora blight of pepper could be enhanced as an aspect of radiation hormesis. Analysis and characterization of antioxidant enzyme from plant culture cells and radiation tolerant of transformed plants from antioxidant (POD) were accomplished in the plant irradiated with different dose of {gamma}-ray. (author)

  4. Historical review of radiation research

    Energy Technology Data Exchange (ETDEWEB)

    Lindell, B. [Swedish Radiation Protection Inst., Stockholm (Sweden)

    1997-09-01

    The presentation reviews the history of radiation research beginning with the first findings and attempts for modelling of harmful effects of radiation, followed by the contamination of the environment, use of radiation epidemiology and concluding with the question of cancer generation. (26 refs.).

  5. Radiation protection and environment day the low doses in everyday life; Radioprotection et environnement les faibles doses dans la vie quotidienne

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    The consequences of low doses exposures are difficult to explore and the studies give often place to controversies. According to the are, differences exist in the methodological approaches. It results from it a confusion on the acceptable levels of exposure, even on the definition of low dose. This day organised by the sections 'non ionizing and research and health of the French society of radiation protection (S.F.R.P.), will be a meeting between professionals of different disciplines, to compare the approaches used for the ionizing and non ionizing radiations as well as the chemical and microbiological agents. It will allow to share the knowledge and the abilities and to progress on methodologies adapted to the evaluation and the management of risks in relation with low doses. (N.C.)

  6. Extreme environment electronics

    CERN Document Server

    Cressler, John D

    2012-01-01

    Unfriendly to conventional electronic devices, circuits, and systems, extreme environments represent a serious challenge to designers and mission architects. The first truly comprehensive guide to this specialized field, Extreme Environment Electronics explains the essential aspects of designing and using devices, circuits, and electronic systems intended to operate in extreme environments, including across wide temperature ranges and in radiation-intense scenarios such as space. The Definitive Guide to Extreme Environment Electronics Featuring contributions by some of the world's foremost exp

  7. Solar radiation exposure of shielded air temperature sensors and measurement error evaluation in an urban environment: a preliminary study in Florence, Italy

    Directory of Open Access Journals (Sweden)

    M. Petralli

    2009-04-01

    Full Text Available Particularly in summer, thermal conditions in urban areas are influenced by solar radiation and human health can be strongly affected by the higher temperature regime increased by the Urban Heat Island effect (UHI. Many studies have been carried out to estimate the temperature distribution in urban areas and some of these use or are based on data collected by meteorological instruments placed within the cities. At microscale, temperature collected by sensors can be influenced by the underlying surface characteristics and the closeness to warm surfaces. The aim of this study is to investigate how different exposure to solar radiation can affect air temperature measurement in streets and gardens. The study was carried out on two different areas in Florence during summer 2007. Shielded air temperature sensors were placed in a street of a high density built-up area and in a green area. Each area was monitored by two sensors, sited in different solar radiation exposure: one in a sunny area and the other in a shaded one. A preliminary data analysis showed a difference in every site between the air temperature values collected by the two sensors especially from the morning to the afternoon. The relationship between air temperature differences and synoptic meteorological conditions were also analyzed. In conclusion, the solar radiation exposure of a monitoring station is an important parameter that must be considered both during the instruments siting and the analysis of data collected by sensors previously placed. The result of this study shows that during particular synoptic conditions, data collected by the two sensors of the same area can be different.

  8. Combination of microwave radiation and a nucleophile material in alkaline environment on the destruction of aroclor 1262 in real transformer waste oil

    Directory of Open Access Journals (Sweden)

    Hasan Asilian Mahabadi

    2016-01-01

    Full Text Available Aims: This research was done to assess the dechlorination and destruction of polychlorinated biphenyls (PCBs in real-waste transformer oil via microwave (MW radiation. Materials and Methods: The influence of MW power, reaction time, polyethylene glycol, zero-valent iron powder, sodium hydroxide (NaOH, and water (H 2 O were investigated on the dechlorination and destruction efficiency of PCBs in real-waste transformer oil under MW radiation. Results: The findings show that polyethylene glycol and NaOH have great influence on destruction of PCBs. However, iron (Fe did not have any influence, and H 2 O decreased the destruction efficiency of PCBs. Moreover, experimental data showed that with optimum amount of variables [ie, polyethylene glycol (PEG = 5.4 g, NaOH = 1.13g, Fe = 0.6g, H 2 O = 0.8 mL, and MW power of 800 W], more than 99.9% of PCBs were destructed at reaction time of 6 min. Furthermore, destruction of PCBs in the absence of water increased up to 100% after 6 min. Conclusion: Accordingly, results showed that MW radiation and reactants (PEG and NaOH were very important factors for the destruction of PCBs from real-waste transformer oil.

  9. Metrology of natural radionuclides. Current challenges in radiation protection for industry and the environment; Metrologie natuerlicher Radionuklide. Aktuelle Herausforderungen fuer den Strahlenschutz in Industrie und Umwelt

    Energy Technology Data Exchange (ETDEWEB)

    Maringer, F.J. [Bundesamt fuer Eich- und Vermessungswesen, Wien (Austria). Referat fuer ionisierende Strahlung und Radioaktivitaet; Univ. fuer Bodenkultur, Wien (Austria). Low-Level Counting Lab. Arsenal; Moser, H.; Kabrt, F. [Bundesamt fuer Eich- und Vermessungswesen, Wien (Austria). Referat fuer ionisierende Strahlung und Radioaktivitaet; Baumgartner, A.; Stietka, M. [Univ. fuer Bodenkultur, Wien (Austria). Low-Level Counting Lab. Arsenal

    2015-07-01

    In a range of industrial branches increased activity concentrations of natural radionuclides occur in various NORM materials processed. The ICRP 103 recommendation, and subsequent the IAEA International Basic Safety Standards and the European Basic Safety Standards for Radiation Protection, raised new challenges in radiation protection concerning natural radionuclide metrology and activity measurement methods - in particular for natural decay chain radionuclides ({sup 238}U+, {sup 232}Th+, {sup 235}U+). Especially adequate traceability and optimized measurement uncertainties of applied activity measurement methods are of increasing concern. In this paper a review on radionuclide metrology of natural radionuclides and its implementation to end-user activity measurement methods and practice is presented. This includes an overview on current and emerging drivers, targets, challenges, deliverables, technologies and stakeholders in the field. Current research results on activity measurement standards and instrumentation for natural radionuclides, revised decay data, in-situ measurement methods, NORM reference materials, are covered as well as benefits of natural radionuclide metrology on radiation protection of workers and the public.

  10. Radiation. Protection. Health. Proceedings; Strahlen. Schutz. Gesundheit. Tagungsband

    Energy Technology Data Exchange (ETDEWEB)

    Hajek, Michael [International Atomic Energy Agency, Wien (Austria); Maringer, Franz Josef; Steurer, Andreas [Bundesamt fuer Eich- und Vermessungswesen, Wien (Austria); Schwaiger, Martina [Seibersdorf Labor GmbH, Seibersdorf (Austria); Timal, Guenter (ed.) [Bundesministerium fuer Inneres, Wien (Austria)

    2015-07-01

    The topics of the meeting are the diagnostic and therapeutic application of ionizing radiations, the application of radiation in research, industry and engineering and radiation protection. The volume includes the following chapters: Radiation protection and society, radiation protection infrastructure, population and environment, metrology and measuring techniques, 1. Workshop on population and environment, NORM and radon, 2. Update: dose - extent of damage - limiting value definition, radiation protection for personnel (except medicine), radiation protection in medicine.

  11. Radiation Damage in Electronic Memory Devices

    OpenAIRE

    Irfan Fetahović; Milić Pejović; Miloš Vujisić

    2013-01-01

    This paper investigates the behavior of semiconductor memories exposed to radiation in order to establish their applicability in a radiation environment. The experimental procedure has been used to test radiation hardness of commercial semiconductor memories. Different types of memory chips have been exposed to indirect ionizing radiation by changing radiation dose intensity. The effect of direct ionizing radiation on semiconductor memory behavior has been analyzed by using Monte Carlo simula...

  12. Radiation resistance of lactobacilli isolated from radurized meat relative to growth and environment. [Lactobacillus sake; Lactobacillus curvatus; Lactobacillus farciminis; Staphylococcus aureus; Salmonella typimurium

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, J.W.; Holzapfel, W.H.; Niemand, J.G.

    1986-10-01

    Of 113 lactobacilli isolated from radurized (5 kGy) minced meat, 7 Lactobacillus sake strains, 1 L. curvatus strain, and 1 L. farciminis strain were used for radiation resistance studies in a semisynthetic substrate (i.e., modified MRS broth). Five reference Lactobacillus spp. one Staphylococcus aureus strain, and one Salmonella typhimurium strain were used for comparative purposes. All L. sake isolates exhibited the phenomenon of being more resistant to gamma-irradiation in the exponential (log) phase than in the stationary phase of their growth cycles by a factor of 28%. Four reference strains also exhibited this phenomenon, with L. sake (DSM 20017) showing a 68% increase in resistance in the log phase over the stationary phase. This phenomenon was not common to all bacteria tested and is not common to all strains with high radiation resistance. Four L. sake isolates and three reference strains were used in radiation sensitivity testing in a natural food system (i.e., meat). The bacteria were irradiated in minced meat and packaged under four different conditions (air, vacuum, CO/sub 2/, and N/sub 2/). Organisms exhibited the highest death rate (lowest D/sub 10/ values (doses required to reduce the logarithm of the bacterial population by 1) under CO/sub 2/ packaging conditions, but resistance to irradiation was increased under N/sub 2/. The D/sup 10/ values of the isolates were generally greater than those of the reference strains. The D/sup 10/ values were also higher (approximately two times) in meat than in a semisynthetic growth medium.

  13. Ideas on DC-DC Converters for Delivery of Low Voltage and High Currents for the SLHC / ILC Detector Electronics in Magnetic field and Radiation environments

    CERN Document Server

    Dhawan, Satish; Neal, H; Sumner, R; Weber, M; Weber, R

    2007-01-01

    For more efficient power transport to the electronics embedded inside large colliding beam detectors, we explore the feasibility of supplying 48 Volts DC and using local DCDC conversion to 2 V (or lower, depending upon on the lithography of the embedded electronics) using switch mode regulators located very close to the front end electronics. These devices will be exposed to high radiation and high magnetic fields, 10 – 100 Mrads and 2 - 4 Tesla at the SLHC, and 20 Krads and 6 Tesla at the ILC.

  14. Why Space is Unique? The Basic Environment Challenges for EEE Parts

    Science.gov (United States)

    LaBel, Kenneth A.; Sampson, Michael J.

    2014-01-01

    This presentation includes an introduction the space radiation environment, the effects on electronics, the environment in action, flight projects, mission needs, and radiation hardness assurance (RHA).

  15. Radiation environment simulations at the Tevatron, studies of the beam profile and measurement of the Bc meson mass

    Energy Technology Data Exchange (ETDEWEB)

    Nicolas, Ludovic Y. [Univ. of Glasgow, Scotland (United Kingdom)

    2005-09-01

    The description of a computer simulation of the CDF detector at Fermilab and the adjacent accelerator parts is detailed, with MARS calculations of the radiation background in various elements of the model due to the collision of beams and machine-related losses. Three components of beam halo formation are simulated for the determination of the principal source of radiation background in CDF due to beam losses. The effect of a collimator as a protection for the detector is studied. The simulation results are compared with data taken by a CDF group. Studies of a 150 GeV Tevatron proton beam are performed to investigate the transverse diffusion growth and distribution. A technique of collimator scan is used to scrape the beam under various experimental conditions, and computer programs are written for the beam reconstruction. An average beam halo growth speed is given and the potential of beam tail reconstruction using the collimator scan is evaluated. A particle physics analysis is conducted in order to detect the Bc → J/Ψπ decay signal with the CDF Run II detector in 360 pb-1 of data. The cut variables and an optimization method to determine their values are presented along with a criterion for the detection threshold of the signal. The mass of the B{sub c} meson is measured with an evaluation of the significance of the signal.

  16. Short wave Aerosol Radiative Forcing estimates over a semi urban coastal environment in south-east India and validation with surface flux measurements

    Science.gov (United States)

    Aruna, K.; Lakshmi Kumar, T. V.; Krishna Murthy, B. V.; Babu, S. Suresh; Ratnam, M. Venkat; Rao, D. Narayana

    2016-01-01

    The short wave direct Aerosol Radiative Forcing (ARF) at a semi urban coastal location near Chennai (12.81 °N, 80.03 °E, ˜45 m amsl), a mega city on the east coast of India has been estimated for all the four seasons in the year 2013 using the SBDART (Santa Barbara Discrete ordinate Atmospheric Radiative Transfer) model. As inputs to this model, measured aerosol parameters together with modeled aerosol and atmospheric parameters are used. The ARF in the atmosphere is found to be higher in the pre-monsoon and winter seasons compared to the other seasons whereas at the surface, it is found to be higher in the south-west (SW) monsoon and winter seasons. The estimated ARF values are compared with those reported over other locations in India. The effect of Relative Humidity on ARF has been investigated for the first time in the present study. It is found that the ARF increases with increasing RH in the SW monsoon and winter seasons. An unique feature of the present study is the comparison of the net surface short wave fluxes estimated from the model (SBDART) and measured fluxes using CNR 4 net radiometer. This comparison between the estimated and measured fluxes showed good agreement, providing a 'closure' for the estimates.

  17. Inner Radiation Belt Representation of the Energetic Electron Environment: Model and Data Synthesis Using the Salammbo Radiation Belt Transport Code and Los Alamos Geosynchronous and GPS Energetic Particle Data

    Science.gov (United States)

    Friedel, R. H. W.; Bourdarie, S.; Fennell, J.; Kanekal, S.; Cayton, T. E.

    2004-01-01

    The highly energetic electron environment in the inner magnetosphere (GEO inward) has received a lot of research attention in resent years, as the dynamics of relativistic electron acceleration and transport are not yet fully understood. These electrons can cause deep dielectric charging in any space hardware in the MEO to GEO region. We use a new and novel approach to obtain a global representation of the inner magnetospheric energetic electron environment, which can reproduce the absolute environment (flux) for any spacecraft orbit in that region to within a factor of 2 for the energy range of 100 KeV to 5 MeV electrons, for any levels of magnetospheric activity. We combine the extensive set of inner magnetospheric energetic electron observations available at Los Alamos with the physics based Salammbo transport code, using the data assimilation technique of "nudging". This in effect input in-situ data into the code and allows the diffusion mechanisms in the code to interpolate the data into regions and times of no data availability. We present here details of the methods used, both in the data assimilation process and in the necessary inter-calibration of the input data used. We will present sample runs of the model/data code and compare the results to test spacecraft data not used in the data assimilation process.

  18. Standard Practice for Application and Analysis of Nuclear Research Emulsions for Fast Neutron Dosimetry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 Nuclear Research Emulsions (NRE) have a long and illustrious history of applications in the physical sciences, earth sciences and biological sciences (1,2) . In the physical sciences, NRE experiments have led to many fundamental discoveries in such diverse disciplines as nuclear physics, cosmic ray physics and high energy physics. In the applied physical sciences, NRE have been used in neutron physics experiments in both fission and fusion reactor environments (3-6). Numerous NRE neutron experiments can be found in other applied disciplines, such as nuclear engineering, environmental monitoring and health physics. Given the breadth of NRE applications, there exist many textbooks and handbooks that provide considerable detail on the techniques used in the NRE method. As a consequence, this practice will be restricted to the application of the NRE method for neutron measurements in reactor physics and nuclear engineering with particular emphasis on neutron dosimetry in benchmark fields (see Matrix E706). 1...

  19. Radiation Therapy

    Science.gov (United States)

    Radiation therapy is a cancer treatment. It uses high doses of radiation to kill cancer cells and stop them from ... half of all cancer patients receive it. The radiation may be external, from special machines, or internal, ...

  20. Radiation dosimetry

    CERN Document Server

    Hine, Gerald J; Hine, Gerald J

    1956-01-01

    Radiation Dosimetry focuses on the advancements, processes, technologies, techniques, and principles involved in radiation dosimetry, including counters and calibration and standardization techniques. The selection first offers information on radiation units and the theory of ionization dosimetry and interaction of radiation with matter. Topics include quantities derivable from roentgens, determination of dose in roentgens, ionization dosimetry of high-energy photons and corpuscular radiations, and heavy charged particles. The text then examines the biological and medical effects of radiation,

  1. Red drifters and dark residents: the phylogeny and ecology of a Plio-Pleistocene dragonfly radiation reflects Africa's changing environment (Odonata, Libellulidae, Trithemis).

    Science.gov (United States)

    Damm, Sandra; Dijkstra, Klaas-Douwe B; Hadrys, Heike

    2010-03-01

    In the last few million years, tropical Africa has experienced pronounced climatic shifts with progressive aridification. Such changes must have had a great impact on freshwater biota, such as Odonata. With about forty species, Trithemis dominates dragonfly communities across Africa, from rain-pools to streams, deserts to rainforests, and lowlands to highlands. Red-bodied species tend to favor exposed, standing and often temporary waters, have strong dispersal capacities, and some of the largest geographic ranges in the genus. Those in cooler habitats, like forest streams, are generally dark-bodied and more sedentary. We combined molecular analyses of ND1, 16S, and ITS (ITSI, 5.8S, and ITSII) with morphological, ecological, and geographical data for 81% of known Trithemis species, including three Asian and two Madagascan endemics. Using molecular clock analyses, the genus's origin was estimated 6-9Mya, with multiple lineages arising suddenly around 4Mya. Open stagnant habitats were inferred to be ancestral and the rise of Trithemis may have coincided with savannah-expansion in the late Miocene. The adaptation of red species to more ephemeral conditions leads to large ranges and limited radiation within those lineages. By contrast, three clades of dark species radiated in the Plio-Pleistocene, each within distinct ecological confines: (1) lowland streams, (2) highland streams, and (3) swampy habitats on alternating sides of the Congo-Zambezi watershed divide; together giving rise to the majority of species diversity in the genus. During Trithemis evolution, multiple shifts from open to more forested habitats and from standing to running waters occurred. Allopatry by habitat fragmentation may be the dominant force in speciation, but possibly genetic divergence across habitat gradients was also involved. The study demonstrates the importance of combining ecological and phylogenetic data to understand the origin of biological diversity under great environmental change.

  2. Solar cell radiation handbook

    Science.gov (United States)

    Tada, H. Y.; Carter, J. R., Jr.; Anspaugh, B. E.; Downing, R. G.

    1982-01-01

    The handbook to predict the degradation of solar cell electrical performance in any given space radiation environment is presented. Solar cell theory, cell manufacturing and how they are modeled mathematically are described. The interaction of energetic charged particles radiation with solar cells is discussed and the concept of 1 MeV equivalent electron fluence is introduced. The space radiation environment is described and methods of calculating equivalent fluences for the space environment are developed. A computer program was written to perform the equivalent fluence calculations and a FORTRAN listing of the program is included. Data detailing the degradation of solar cell electrical parameters as a function of 1 MeV electron fluence are presented.

  3. Compound Semiconductor Radiation Detectors

    CERN Document Server

    Owens, Alan

    2012-01-01

    Although elemental semiconductors such as silicon and germanium are standard for energy dispersive spectroscopy in the laboratory, their use for an increasing range of applications is becoming marginalized by their physical limitations, namely the need for ancillary cooling, their modest stopping powers, and radiation intolerance. Compound semiconductors, on the other hand, encompass such a wide range of physical and electronic properties that they have become viable competitors in a number of applications. Compound Semiconductor Radiation Detectors is a consolidated source of information on all aspects of the use of compound semiconductors for radiation detection and measurement. Serious Competitors to Germanium and Silicon Radiation Detectors Wide-gap compound semiconductors offer the ability to operate in a range of hostile thermal and radiation environments while still maintaining sub-keV spectral resolution at X-ray wavelengths. Narrow-gap materials offer the potential of exceeding the spectral resolutio...

  4. Applications of ionizing radiations

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2014-07-01

    Developments in standard applications and brand new nuclear technologies, with high impact on the future of the agriculture, medicine, industry and the environmental preservation. The Radiation Technology Center (CTR) mission is to apply the radiation and radioisotope technologies in Industry, Health, Agriculture, and Environmental Protection, expanding the scientific knowledge, improving human power resources, transferring technology, generating products and offering services for the Brazilian society. The CTR main R and D activities are in consonance with the IPEN Director Plan (2011-2013) and the Applications of Ionizing Radiation Program, with four subprograms: Irradiation of Food and Agricultural Products; Radiation and Radioisotopes Applications in Industry and Environment; Radioactive Sources and Radiation Applications in Human Health; and Radioactive Facilities and Equipment for the Applications of Nuclear Techniques.

  5. Effect of Rana japonica oil compound granules on learning/memory ability of rats exposed to microwave radiation under hypergravity environment%林蛙油冲剂对微波辐射大鼠学习记忆影响

    Institute of Scientific and Technical Information of China (English)

    陈默然; 高俊涛; 李妍; 李强; 赵行宇; 任旷; 沈楠; 潘文干

    2011-01-01

    目的 观察林蛙油复方冲剂对超重环境下微波辐射大鼠学习记忆能力影响.方法 制备Wistar大鼠超重环境下微波辐射模型,采用林蛙油冲剂进行干预,连续14 d,Moms水迷宫实验观察学习记忆能力改变,western blot检测大脑皮层热休克蛋白70 (HSP70)表达.结果 与空白对照比较,模型组定位航行潜伏期由(12.03±1.85)s延长至(32.54±5.75)s(P <0.05),跨平台次数由(6.45±1.35)次/min减少至(2.16±1.02)次/min(P<0.05),脑组织HSP70表达明显升高(P<0.05);与模型组比较,林蛙油冲剂辐射前处理组定位航行潜伏期缩短至(13.88±5.93)s(P<0.05),跨平台次数增加至(5.91±1.53)次/min(P<0.05),脑组织HSP70蛋白表达降低(P<0.05).结论 林蛙油复方冲剂可改善超重环境下微波辐射模型大鼠学习记忆能力,其机制可能与降低大脑皮层组织HSP70表达有关.%Objective To assess the effect of Rana japonica oil compound granules on the ability of learning/ memory of the rats exposed to microwave radiation under hypergravity environment. Methods The model of Wistar rats under syn-ergistic effect of hypergravity environment and microwave radiation was established and the rats were intervened with Rana japonica oil compound granules for 14 days. Morris water maze was used to detect the ability of learning and memory of the rats and the expression of heat shock protein 70 (HSP70) in the cortex of the rats were determined with western blot. Results Compared with blank control group, the escape latency of the rats in model group was significantly prolonged from 12. 03 ± 1. 85 seconds to 32. 54 ± 5.75 seconds( P < 0.05) and the number of finding the platform was decreased remarkably from 6.45 ± 1. 35 per minute to 2.16 ± 1.02 per minute(P <0. 05). The expression of HSP70 in the cortex increased significantly (P < 0. 05) and significantly decreased in compound granules protection group before hypergravity and radiation treatment (P<0

  6. Aerosol optical properties in a rural environment near the mega-city Guangzhou, China: implications for regional air pollution and radiative forcing

    Directory of Open Access Journals (Sweden)

    R. M. Garland

    2008-04-01

    Full Text Available The scattering and absorption of solar radiation by atmospheric aerosols is a key element of the Earth's radiative energy balance and climate. The optical properties of aerosol particles are, however, highly variable and not well characterized, especially near newly emerging mega-cities. In this study, aerosol optical properties were measured at a regional background site approximately 60 km northwest of the mega-city Guangzhou in southeast China. The measurements were part of the "Program of Regional Integrated Experiments of Air Quality over the Pearl River Delta" intensive campaign (PRIDE-PRD2006, covering the period of 1–30 July 2006. Scattering and absorption coefficients of dry aerosol particles with diameters up to 10 μm (PM10 were determined with a three-wavelength integrating nephelometer and with a photoacoustic spectrometer, respectively.

    Averaged over the measurement campaign (arithmetic mean ±standard deviation, the total scattering coefficients were 200±133 Mm−1 (450 nm, 151±103 Mm−1 (550 nm and 104±72 Mm−1 (700 nm and the absorption coefficient was 34.3±26.5 Mm−1 (532 nm. The average Ångström exponent was 1.46±0.21 (450 nm/700 nm and the average single scattering albedo was 0.82±0.07 (532 nm with minimum values as low as 0.5. The low single scattering albedo values indicate a high abundance of, as well as strong sources of light absorbing carbon (LAC. The ratio of LAC to CO concentration was highly variable throughout the campaign, indicating a complex mix of different combustion sources. The scattering and absorption coefficients, as well as the Ångström exponent and single scattering albedo, exhibited pronounced diurnal cycles, which can be attributed to boundary layer mixing effects and enhanced nighttime emissions of LAC (diesel soot from regulated truck traffic. The daytime average single scattering albedo of 0.87 appears to be more

  7. Aerosol optical properties in a rural environment near the mega-city Guangzhou, China: implications for regional air pollution, radiative forcing and remote sensing

    Directory of Open Access Journals (Sweden)

    Y. H. Zhang

    2008-09-01

    Full Text Available The scattering and absorption of solar radiation by atmospheric aerosols is a key element of the Earth's radiative energy balance and climate. The optical properties of aerosol particles are, however, highly variable and not well characterized, especially near newly emerging mega-cities. In this study, aerosol optical properties were measured at a rural site approximately 60 km northwest of the mega-city Guangzhou in southeast China. The measurements were part of the PRIDE-PRD2006 intensive campaign, covering the period of 1–30 July 2006. Scattering and absorption coefficients of dry aerosol particles with diameters up to 10 μm (PM10 were determined with a three-wavelength integrating nephelometer and with a photoacoustic spectrometer, respectively.

    Averaged over the measurement campaign (arithmetic mean ± standard deviation, the total scattering coefficients were 200±133 Mm−1 (450 nm, 151±103 Mm−1 (550 nm and 104±72 Mm−1 (700 nm and the absorption coefficient was 34.3±26.5 Mm−1 (532 nm. The average Ångström exponent was 1.46±0.21 (450 nm/700 nm and the average single scattering albedo was 0.82±0.07 (532 nm with minimum values as low as 0.5. The low single scattering albedo values indicate a high abundance, as well as strong sources, of light absorbing carbon (LAC. The ratio of LAC to CO concentration was highly variable throughout the campaign, indicating a complex mix of different combustion sources. The scattering and absorption coefficients, as well as the Ångström exponent and single scattering albedo, exhibited pronounced diurnal cycles, which can be attributed to boundary layer mixing effects and enhanced nighttime emissions of LAC (diesel soot from regulated truck traffic. The daytime average mid-visible single scattering albedo of 0.87 appears to be more suitable for climate modeling purposes than the 24-h average of 0.82, as the latter value is

  8. Ionizing radiation sources: very diversified means, multiple applications and a changing regulatory environment. Conference proceedings; Les sources de rayonnements ionisants: des moyens tres diversifies, des applications multiples et une reglementation en evolution. Recueil des presentations

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-11-15

    This document brings together the available presentations given at the conference organised by the French society of radiation protection about ionizing radiation source means, applications and regulatory environment. Twenty eight presentations (slides) are compiled in this document and deal with: 1 - Overview of sources - some quantitative data from the national inventory of ionizing radiation sources (Yann Billarand, IRSN); 2 - Overview of sources (Jerome Fradin, ASN); 3 - Regulatory framework (Sylvie Rodde, ASN); 4 - Alternatives to Iridium radiography - the case of pressure devices at the manufacturing stage (Henri Walaszek, Cetim; Bruno Kowalski, Welding Institute); 5 - Dosimetric stakes of medical scanner examinations (Jean-Louis Greffe, Charleroi hospital of Medical University); 6 - The removal of ionic smoke detectors (Bruno Charpentier, ASN); 7 - Joint-activity and reciprocal liabilities - Organisation of labour risk prevention in case of companies joint-activity (Paulo Pinto, DGT); 8 - Consideration of gamma-graphic testing in the organization of a unit outage activities (Jean-Gabriel Leonard, EDF); 9 - Radiological risk control at a closed and independent work field (Stephane Sartelet, Areva); 10 - Incidents and accidents status and typology (Pascale Scanff, IRSN); 11 - Regional overview of radiation protection significant events (Philippe Menechal, ASN); 12 - Incident leading to a tritium contamination in and urban area - consequences and experience feedback (Laurence Fusil, CEA); 13 - Experience feedback - loss of sealing of a calibration source (Philippe Mougnard, Areva); 14 - Blocking incident of a {sup 60}Co source (Bruno Delille, Salvarem); 15 - Triggering of gantry's alarm: status of findings (Philippe Prat, Syctom); 16 - Non-medical electric devices: regulatory changes (Sophie Dagois, IRSN; Jerome Fradin, ASN); 17 - Evaluation of the dose equivalent rate in pulsed fields: method proposed by the IRSN and implementation test (Laurent Donadille

  9. Advanced Multifunctional MMOD Shield: Radiation Shielding Assessment

    Science.gov (United States)

    Rojdev, Kristina; Christiansen, Eric

    2013-01-01

    Deep space missions must contend with a harsh radiation environment Impacts to crew and electronics. Need to invest in multifunctionality for spacecraft optimization. MMOD shield. Goals: Increase radiation mitigation potential. Retain overall MMOD shielding performance.

  10. Radiation hormesis in plant

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Sung; Song, Hi Sup; Lee, Young Keun; Cun, Ki Jung; Shin, In Chul; Lim, Young Taek

    1999-04-01

    This research was performed to investigate the effects of low dose {gamma}-ray radiation on the seed germination and the following physiological responses in vegetable crops. Special attention was focused on whether the resistance of vegetables against the unfavorable conditions of environment such as acid rain or soil types could be enhanced as an aspect of radiation hormesis. Analysis and characterization of antioxidant enzyme from plant culture cells and radiation tolerant of transformed plants from antioxidant enzyme (POD) were accomplished in the plant irradiated with difference dosage of {gamma}-ray.

  11. Radiation protection

    CERN Document Server

    CERN. Geneva

    2001-01-01

    This will be a simple explanation of the reasons why CERN has to be careful about radiation protections issues, a practical guide on how to recognize radiation dangers, the monitoring systems that make sure radiation levels are well tolerable norms, and a quick summary of what radiation levels mean in terms of personal risk.

  12. Effects of target fragmentation on evaluation of LET spectra from space radiation in low-earth orbit (LEO) environment: impact on SEU predictions

    Science.gov (United States)

    Shinn, J. L.; Cucinotta, F. A.; Wilson, J. W.; Badhwar, G. D.; O'Neill, P. M.; Badavi, F. F.

    1995-01-01

    Recent improvements in the radiation transport code HZETRN/BRYNTRN and galactic cosmic ray environmental model have provided an opportunity to investigate the effects of target fragmentation on estimates of single event upset (SEU) rates for spacecraft memory devices. Since target fragments are mostly of very low energy, an SEU prediction model has been derived in terms of particle energy rather than linear energy transfer (LET) to account for nonlinear relationship between range and energy. Predictions are made for SEU rates observed on two Shuttle flights, each at low and high inclination orbit. Corrections due to track structure effects are made for both high energy ions with track structure larger than device sensitive volume and for low energy ions with dense track where charge recombination is important. Results indicate contributions from target fragments are relatively important at large shield depths (or any thick structure material) and at low inclination orbit. Consequently, a more consistent set of predictions for upset rates observed in these two flights is reached when compared to an earlier analysis with CREME model. It is also observed that the errors produced by assuming linear relationship in range and energy in the earlier analysis have fortuitously canceled out the errors for not considering target fragmentation and track structure effects.

  13. STUDY OF RADIATION EXPOSURE DUE TO RADON, THORON AND THEIR PROGENY IN THE INDOOR ENVIRONMENT OF RAJPUR REGION OF UTTARAKHAND HIMALAYA.

    Science.gov (United States)

    Kandari, Tushar; Aswal, Sunita; Prasad, Mukesh; Pant, Preeti; Bourai, A A; Ramola, R C

    2016-10-01

    In the present study, the measurements of indoor radon, thoron and their progeny concentrations have been carried out in the Rajpur region of Uttarakhand, Himalaya, India by using LR-115 solid-state nuclear track detector-based time-integrated techniques. The gas concentrations have been measured by single-entry pin-hole dosemeter technique, while for the progeny concentrations, deposition-based Direct Thoron and Radon Progeny Sensor technique has been used. The radiation doses due to the inhalation of radon, thoron and progeny have also been determined by using obtained concentrations of radon, thoron and their progeny in the study area. The average radon concentration varies from 75 to 123 Bq m(-3) with an overall average of 89 Bq m(-3) The average thoron concentration varies from 29 to 55 Bq m(-3) with an overall average of 38 Bq m(-3) The total annual effective dose received due to radon, thoron and their progeny varies from 2.4 to 4.1 mSv y(-1) with an average of 2.9 mSv y(-1) While the average equilibrium factor for radon and its progeny was found to be 0.39, for thoron and its progeny, it was 0.06. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Firmware Development and Integration for ALICE TPC and PHOS Front-end Electronics A Trigger Based Readout and Control System operating in a Radiation Environment

    CERN Document Server

    AUTHOR|(CDS)2068589; Rohrich, Dieter

    2008-01-01

    The readout electronics in PHOS and TPC - two of the major detectors of the ALICE experiment at the LHC - consist of a set of Front End Cards (FECs) that digitize, process and buffer the data from the detector sensors. The FECs are connected to a Readout Control Unit (RCU) via two sets of custom made PCB backplanes. For PHOS, 28 FECs are connected to one RCU, while for TPC the number is varying from 18 to 25 FECs depending on location. The RCU is in charge of the data readout, including reception and distribution of triggers and in moving the data from the FECs to the Data Acquisition System. In addition it does low level control tasks. The RCU consists of an RCU Motherboard that hosts a Detector Control System (DCS) board and a Source Interface Unit. The DCS board is an embedded computer running Linux that controls the readout electronics. All the mentioned devices are implemented in commercial grade SRAM based Field Programmable Gate Arrays (FPGAs). Even if these devices are not very radiation tolerant, the...

  15. Probing X-ray photoevaporative winds through their interaction with ionising radiation in cluster environments: the case for X-ray proplyds

    CERN Document Server

    Clarke, C J

    2014-01-01

    We show that if young low mass stars undergo vigorous X-ray driven disc winds, these may be detected in clusters through their interaction with ionising radiation from massive stars. We argue that in the ONC (Orion Nebula Cluster) one should see $\\sim$ 10s of `X-ray proplyds' ( objects with optically imaged offset ionisation fronts) in the range $0.3-0.6$pc from $\\theta_1$C Ori (the dominant O star in the ONC). Such objects lie outside the central `FUV zone' in the ONC where proplyds are instead well explained by neutral winds driven by external Far Ultraviolet (FUV) emission from $\\theta_1$C. We show that the predicted numbers and sizes of X-ray proplyds are compatible with those observed and that this may also explain at least some of the far flung proplyds seen in the Carina nebula. We compare the sizes of observed proplyds outside the FUV region of the ONC with model predictions based on the current observed X-ray luminosities of these sources ( bearing in mind that the current size is actually set by the...

  16. Spectral-Domain-Based Scattering Analysis of Fields Radiated by Distributed Sources in Planar-Stratified Environments with Arbitrarily Anisotropic Layers

    CERN Document Server

    Sainath, Kamalesh

    2014-01-01

    We discuss the numerically stable computation and extraction of the scattered electromagnetic field excited by distributed sources embedded in planar-layered environments where each layer may exhibit arbitrary and independent electrical and magnetic anisotropic response and loss profiles. Although the scattered field computation appears analytically relatively straightforward, different procedures within the computation chain, if not treated carefully, are inherently susceptible to numerical instabilities and (or) accuracy limitations due to the potential manifestation of numerically overflown and (or) numerically unbalanced terms entering the chain. Therefore, primary emphasis is given to effecting these tasks in a numerically stable and robust manner for all ranges of physical parameters. We validate the results against closed-form solutions and provide a computational efficiency study demonstrating a drastic reduction in computation time realized via the spectral domain (i.e., $k$-space or, equivalently, m...

  17. Radiation Damage in Electronic Memory Devices

    Directory of Open Access Journals (Sweden)

    Irfan Fetahović

    2013-01-01

    Full Text Available This paper investigates the behavior of semiconductor memories exposed to radiation in order to establish their applicability in a radiation environment. The experimental procedure has been used to test radiation hardness of commercial semiconductor memories. Different types of memory chips have been exposed to indirect ionizing radiation by changing radiation dose intensity. The effect of direct ionizing radiation on semiconductor memory behavior has been analyzed by using Monte Carlo simulation method. Obtained results show that gamma radiation causes decrease in threshold voltage, being proportional to the absorbed dose of radiation. Monte Carlo simulations of radiation interaction with material proved to be significant and can be a good estimation tool in probing semiconductor memory behavior in radiation environment.

  18. Radiation design criteria handbook. [design criteria for electronic parts applications

    Science.gov (United States)

    Stanley, A. G.; Martin, K. E.; Douglas, S.

    1976-01-01

    Radiation design criteria for electronic parts applications in space environments are provided. The data were compiled from the Mariner/Jupiter Saturn 1977 electronic parts radiation test program. Radiation sensitive device types were exposed to radiation environments compatible with the MJS'77 requirements under suitable bias conditions. A total of 189 integrated circuits, transistors, and other semiconductor device types were tested.

  19. 飞机进近着陆电磁环境建模与辐射分布分析%Modeling of electromagnetic environment and radiation distribution analysis for aircraft approaching and landing

    Institute of Scientific and Technical Information of China (English)

    王磊; 苏东林; 谢树果; 赵子华

    2012-01-01

    Electromagnetic field, terrain and obstacle are three vital elements which constitute electro- magnetic environment in aerodrome terminal. Because of their inhomogeneity in topology, physics and seman- teme, it is difficult to express the characteristic of the electromagnetic environment for aircraft approaching and landing with determined model. Based on the attribute of hierarchy and the coupling interrelation of those three elements, a multi-layer fused electromagnetic environment model frame for aerodrome terminal was put for- ward. In order to reduce the computation error induced by the non-regulation boundary variation of electromag- netic field, a combination of method of moment(MoM) and ray tracing methods was used to simulate the radi- ation pattern and wave propagation, and radiation intensity expression and distribution computation flow in ap- proaching and landing area were described. Simulation experiment of the radiation computation in approaching area based on one aerodrome dataset shows the validity of the modeling method.%机场终端区电磁、地形和地物在拓扑、物理和语义上的异构性导致进近着陆电磁环境构成机理复杂,很难用单尺度解析模型表征电磁环境的本质属性.在分析终端区多要素层次构成机理和关联耦合特征的基础上,提出一种多层融合的进近着陆电磁环境模型架构.综合采用矩量法和射线追踪法模拟台站辐射特性和地空电波传播模式,建立进近着陆区域电磁辐射强度量化表征与空间分布计算模型,有效降低了场边界特性不规则时空变化带来的电波预测误差.结合某机场地形和航向台数据,对终端区主航道和余隙航道的电磁辐射强度和覆盖范围进行计算和对比分析.仿真结果验证了本建模与分析方法的有效性.

  20. Radiation Therapy: Professions in Radiation Therapy

    Science.gov (United States)

    ... Resources Professions Site Index A-Z Professions in Radiation Therapy Radiation Oncologist Therapeutic Medical Physicist Radiation Therapist Dosimetrist Radiation Oncology Nurse Social Worker Dietitian Radiation Oncologist Radiation oncologists are physicians who oversee the ...

  1. Simple dynamic electromagnetic radiation detector

    Science.gov (United States)

    Been, J. F.

    1972-01-01

    Detector monitors gamma dose rate at particular position in a radiation facility where a mixed neutron-gamma environment exists, thus determining reactor power level changes. Device also maps gamma intensity profile across a neutron-gamma beam.

  2. National congress of radiation protection; Congres national de radioprotection

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The congress of radiation protection tackled different areas of radiation protection. The impact of ionizing radiations on environment coming from radioactive activities. The biological radiation effects, the dosimetry, the different ways of doing relative to radiation protection,the risks analysis and the communications with populations, information about accidents and the lessons learned from them are included in this congress. (N.C.)

  3. Air and radiation monitoring stations

    CERN Multimedia

    AUTHOR|(SzGeCERN)582709

    2015-01-01

    CERN has around 100 monitoring stations on and around its sites. New radiation measuring stations, capable of detecting even lower levels of radiation, were installed in 2014. Two members of HE-SEE group (Safety Engineering and Environment group) in front of one of the new monitoring stations.

  4. Teaching about Natural Background Radiation

    Science.gov (United States)

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

    2013-01-01

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

  5. Equivalent calculation between coupling responses of electromagnetic fields from radiating-wave simulators and actual environment%模拟器电磁场与实际电磁场耦合响应等效计算

    Institute of Scientific and Technical Information of China (English)

    李虹轶; 郭春营; 许伟; 林源根

    2016-01-01

    The electromagnetic environment generated by radiating-wave simulators could simulate the free fields of the high altitude electromagnetic pulse (HEMP)approximately.However,the electromagnetic fields imposed on the devices under the real threat environments were the synthesized fields from the incident waves and the reflected waves.The total fields synthesized by the incident and reflected waves of the free electromagnetic fields on different situations above the lossy earth were calculated. Through comparing the field strengths and waveforms of the total fields with the initial incident waves,the features of the synthe-sized fields nearby the ground were analyzed.An equivalent calculating method from the simulated environment to the real envi-ronment was suggested,and the correction factor of the simulated environment was calculated using this method for the 45°polar-ized incident wave.Based on the results,we proposed that the devices should be tested for at least three mutually orthogonal ori-entations and electromagnetic pulse widths should be reduced appropriately for the experiments of radiating-wave simulators.%辐射波模拟器产生的脉冲电磁环境能够近似模拟高空核爆电磁脉冲(HEMP)的自由场,然而在实际 HEMP 威胁环境中,施加在地面设备上的电磁场是电磁脉冲入射波与地面反射波的合成场。通过计算不同入射情况下,HEMP 自由辐射场经损耗地面反射叠加形成的总电场,对比其与初始入射场的强度及波形变化,分析了地面附近合成电磁场的特点。提出一种将模拟环境效应与实际环境效应进行等效转换的计算方法,应用该方法计算了入射波电场45°极化情况下的模拟环境效应修正因子。分析计算结果,建议在开展 HEMP效应的辐射波模拟试验中,应将受试设备放在至少三个相互正交的方向上进行测试,同时适当减小模拟器产生电磁脉冲的宽度。

  6. Radiation Belt and Plasma Model Requirements

    Science.gov (United States)

    Barth, Janet L.

    2005-01-01

    Contents include the following: Radiation belt and plasma model environment. Environment hazards for systems and humans. Need for new models. How models are used. Model requirements. How can space weather community help?

  7. Beneficial uses of radiation

    Energy Technology Data Exchange (ETDEWEB)

    Fox, M.R.

    1991-10-01

    An overall decline in technical literacy within the American public has come at a time when technological advances are accelerating in the United States and around the world. This had led to a large communication gulf between the general public and the technologists. Nowhere is this more evident then with the topic of radiation. Regrettably, too few people know about sources of radiation, the pervasiveness, amounts, and variabilities, and do not have a true understanding of the environment in which we live. Nor do many people know that radiation has been used in beneficial ways for decades around the world. While the general public does not know of the scientific applications to which radiation has been deployed, it nevertheless had benefited tremendously from these efforts. Thanks to the well know properties of radiation, scientific ingenuity has found many uses of radiation in chemical and agricultural research, biomedical research, in the diagnoses and treatment of hundreds of types of diseases, in industrial applications, food irradiation, and many others. This paper provides a sample of the types of uses to which radiation has been used to help advance the betterment of humankind.

  8. Eficiência de uso da radiação fotossinteticamente ativa pela cultura do tomateiro em diferentes ambientes Use efficiency of photosynthetically active radiation by tomato plants grown in different environments

    Directory of Open Access Journals (Sweden)

    Bernadete Radin

    2003-09-01

    Full Text Available A produção de biomassa pelas culturas está relacionada à quantidade de radiação fotossinteticamente ativa interceptada e absorvida pelas folhas, bem como à eficiência com que estas convertem a energia radiante em energia química, pela fotossíntese. O objetivo deste trabalho foi avaliar a eficiência de uso da radiação fotossinteticamente ativa pelo tomateiro (Lycopersicon esculentum Mill. cultivado em diferentes ambientes. Os experimentos foram realizados em estufa de plástico com e sem tela lateral antiinsetos e fora da estufa, em duas épocas (primavera-verão e verão-outono, no ano agrícola de 1999/2000. Mediu-se a matéria seca aérea e o índice de área foliar ao longo dos dois ciclos, assim como os fluxos de radiação incidente e transmitida. O ambiente em estufa com tela lateral antiinsetos teve menos radiação incidente e maior eficiência de seu uso: 0,44 e 0,60 g de matéria seca mol-1, nas primeira e segunda épocas, respectivamente. No ambiente fora da estufa, com mais radiação incidente, houve menor eficiência de seu uso (0,30 e 0,32 g mol-1, enquanto no ambiente em estufa sem tela lateral antiinsetos, foram obtidos valores intermediários de eficiência de uso da radiação (0,45 e 0,53 g mol-1.Crop biomass production is related to the amount of photosynthetically active radiation intercepted and absorbed by the leaves, as well as to their efficiency of conversion of this radiant energy into chemical energy through photosynthesis. The objective of this study was to evaluate the radiation use efficiency by tomato plants (Lycopersicon esculentum Mill. grown in different environments. Experiments were carried out in plastic-covered greenhouses with and without antiinsects screens and at open air plots, in different growth periods (spring-summer and summer-autumn during the 1999/2000 crop season. Measurements of dry above-ground biomass and leaf area index throughout both crop cycles were performed, and the

  9. Radiation environment effects of amplitude modulation wave on a certain radio fuze%无线电引信调幅波电磁辐射环境效应研究

    Institute of Scientific and Technical Information of China (English)

    陈亚洲; 程二威; 费支强; 高磊

    2011-01-01

    To investigate the elecromagnetic environment effects of the amplitude modulation wave on radio fuze,the mixing theory and the output signal character of high frequency circuit are analyzed,and the problems of waveform modulate are resolved.The modulate waveform expression and the radio fuze radiation electromagnetic environment is established.The experiment is done to find out the threshold field intensity for accidental explosion and the variable rules of the radio fuze.The conclusions show that when radiation frequency is appressed with the vibration frequency,the threshold field intensity is less than 10V/m.With the frequency deviation increasing,the threshold field intensity becomes larger.The electronic components of the radio fuze is not destroyed.%为了研究调幅波对无线电引信的电磁环境效应,分析了无线电引信混频原理及高频电路输出信号特征,解决了调幅波的波形调制问题,建立了辐照调幅波的波形表达式,形成了无线电引信辐照电磁环境,探索了不同频率调幅波对引信的意外发火场强干扰阈值及其变化规律。结果表明:辐照频率在引信本振频率外一定范围内引信误炸干扰阈值低于10V/m,随着辐照频率与引信本振频率偏移量增加误炸干扰阈值呈增大趋势;调幅波辐照不会对引信电子部件产生硬损伤,也不会导致引信瞎火。

  10. CERN and the environment

    CERN Multimedia

    Corinne Pralavorio

    2016-01-01

    New webpages answer common questions about CERN and the environment.   One of the new public webpages dedicated to CERN and the environment. Do your neighbours ever ask you about CERN’s environmental impact? And about radiation in particular? If so, the answers to those questions can now be found online on a new set of public webpages dedicated to CERN and the environment. These pages, put together by the Occupational Health, Safety and Environmental Protection (HSE) unit and the groups responsible for CERN's site maintenance, contain a wealth of information on topics linked to the environment, such as biodiversity at CERN, waste management, ionising radiation, and water and electricity consumption. “CERN forms part of the local landscape, with its numerous sites and scientific activities. It’s understandable that people living nearby have questions about the impact of these activities and it’s important that we respond with complete transp...

  11. Pelvic radiation - discharge

    Science.gov (United States)

    Radiation of the pelvis - discharge; Cancer treatment - pelvic radiation; Prostate cancer - pelvic radiation; Ovarian cancer - pelvic radiation; Cervical cancer - pelvic radiation; Uterine cancer - pelvic radiation; Rectal cancer - pelvic radiation

  12. Main Technical Analysis of Quartz Lamp Radiation Transient Thermal Environment Experiment Main Technical Analysis%石英灯辐射式瞬态热环境试验关键技术分析

    Institute of Scientific and Technical Information of China (English)

    王德成; 林辉

    2016-01-01

    ABSTRACT:Based on the characteristics of quartz lamp radiation heater, the influence of following factors on experiment performance is was analyzed, such as sensor weak signal transmit, reactive power compensation, intelligent control, profile modeling heater design and open loop experiment way. Combined with the implementation of transient thermal environment experiment implementation process, the corresponding corrective actions based on the above constraint thermal experiment im-plementation aspects wereare given, in order to improve the effectiveness of transient thermal experiment of experiment system.%结合石英灯辐射式加热器的特性,从传感器弱信号传输、无功补偿、智能控制、仿形加热器、开环试验技术等角度出发,分析了对型号瞬态热试验性能的影响。结合瞬态热试验的实施,给出了上述几个角度制约热试验实施的改进措施,以期提高试验系统瞬态热试验的有效性。

  13. Present status of radiation education in Bangladesh

    Energy Technology Data Exchange (ETDEWEB)

    Ullah, Sana [Atomic Energy Centre, Dhaka (Bangladesh)

    1999-09-01

    Radioisotopes and Radiation are being widely used in the fields of agriculture, medicine, industry for the benefit of people throughout the world. At the same time the use of radiation sources can do harm to man and environment. In order to ensure the satiety against radiation hazards and safe use of radiation, proper education, training, knowledge and awareness are essential. Like other achieve economic development through application f count rues Bangladesh is flying to in agriculture, food, industry, power; health or medi of isotopes and radiation technology cine. Basic education about radiation is incorporated in the school curriculum. Courses on radiation are also given in college and university education. Research organizations, universities carry out research and development works on different disciplines using radiation and radioisotopes. Seminars, workshops, conferences, takings on isotopes and radiation are also being organized. In 1993 Government of Bangladesh passed the Nuclear Satiety and Radiation Control Act 1993 for see use of radiation. The present paper win cover the radiation education, research and development works on radiation, applications of radiation in agriculture, medicine and industry, personal safety and radiation protection against radiation hazard and rules and regulations of the nuclear safety and radiation control act practised in Bangladesh. (author)

  14. Atmospheric radiation flight dose rates

    Science.gov (United States)

    Tobiska, W. K.

    2015-12-01

    Space weather's effects upon the near-Earth environment are due to dynamic changes in the energy transfer processes from the Sun's photons, particles, and fields. Of the domains that are affected by space weather, the coupling between the solar and galactic high-energy particles, the magnetosphere, and atmospheric regions can significantly affect humans and our technology as a result of radiation exposure. Space Environment Technologies (SET) has been conducting space weather observations of the atmospheric radiation environment at aviation altitudes that will eventually be transitioned into air traffic management operations. The Automated Radiation Measurements for Aerospace Safety (ARMAS) system and Upper-atmospheric Space and Earth Weather eXperiment (USEWX) both are providing dose rate measurements. Both activities are under the ARMAS goal of providing the "weather" of the radiation environment to improve aircraft crew and passenger safety. Over 5-dozen ARMAS and USEWX flights have successfully demonstrated the operation of a micro dosimeter on commercial aviation altitude aircraft that captures the real-time radiation environment resulting from Galactic Cosmic Rays and Solar Energetic Particles. The real-time radiation exposure is computed as an effective dose rate (body-averaged over the radiative-sensitive organs and tissues in units of microsieverts per hour); total ionizing dose is captured on the aircraft, downlinked in real-time, processed on the ground into effective dose rates, compared with NASA's Langley Research Center (LaRC) most recent Nowcast of Atmospheric Ionizing Radiation System (NAIRAS) global radiation climatology model runs, and then made available to end users via the web and smart phone apps. Flight altitudes now exceed 60,000 ft. and extend above commercial aviation altitudes into the stratosphere. In this presentation we describe recent ARMAS and USEWX results.

  15. Radiation carcinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Fry, R.J.M.

    1976-01-01

    The risk of iatrogenic tumors with radiation therapy is so outweighed by the benefit of cure that estimates of risk have not been considered necessary. However, with the introduction of chemotherapy, combined therapy, and particle radiation therapy, the comparative risks should be examined. In the case of radiation, total dose, fractionation, dose rate, dose distribution, and radiation quality should be considered in the estimation of risk. The biological factors that must be considered include incidence of tumors, latent period, degree of malignancy, and multiplicity of tumors. The risk of radiation induction of tumors is influenced by the genotype, sex, and age of the patient, the tissues that will be exposed, and previous therapy. With chemotherapy the number of cells at risk is usually markedly higher than with radiation therapy. Clearly the problem of the estimation of comparative risks is complex. This paper presents the current views on the comparative risks and the importance of the various factors that influence the estimation of risk.

  16. Radiation acoustics

    CERN Document Server

    Lyamshev, Leonid M

    2004-01-01

    Radiation acoustics is a developing field lying at the intersection of acoustics, high-energy physics, nuclear physics, and condensed matter physics. Radiation Acoustics is among the first books to address this promising field of study, and the first to collect all of the most significant results achieved since research in this area began in earnest in the 1970s.The book begins by reviewing the data on elementary particles, absorption of penetrating radiation in a substance, and the mechanisms of acoustic radiation excitation. The next seven chapters present a theoretical treatment of thermoradiation sound generation in condensed media under the action of modulated penetrating radiation and radiation pulses. The author explores particular features of the acoustic fields of moving thermoradiation sound sources, sound excitation by single high-energy particles, and the efficiency and optimal conditions of thermoradiation sound generation. Experimental results follow the theoretical discussions, and these clearl...

  17. Hawking radiation

    Science.gov (United States)

    Parentani, Renaud; Spindel, Philippe

    2011-12-01

    Hawking radiation is the thermal radiation predicted to be spontaneously emitted by black holes. It arises from the steady conversion of quantum vacuum fluctuations into pairs of particles, one of which escaping at infinity while the other is trapped inside the black hole horizon. It is named after the physicist Stephen Hawking who derived its existence in 1974. This radiation reduces the mass of black holes and is therefore also known as black hole evaporation.

  18. Contribution to the study of recovery mechanisms to be considered in the selection of MOS-type components used in radiative environments; Contribution a l'etude des mecanismes de guerison intervenant dans la selection des composants de type MOS utilises en environnements radiatifs

    Energy Technology Data Exchange (ETDEWEB)

    Quittard, O

    1999-12-01

    The generalized use of commercial devices in a radiative environment (nuclear power plant, spatial) raises the problem of the sensitivity of electronic equipment to the radiation induced dose effect. Irradiation of electronic devices has varying impact on their electrical characteristics, according to the concomitant bias scenario. Under bias, there is a process of continuous degradation; but recovery will occur if subsequent irradiation is performed without bias voltage. This phenomenon is known as RICN (Radiation-Induced Charge Neutralization). On the other hand, increasingly widespread use of radiation-sensitive commercial off-the-shelf components (COTS) has raised interest in exploring the degradation and recovery phenomena encountered during the irradiation as a function of bias. In this work, a general method for selecting MOS devices is presented which takes into account their operating conditions (temperature, bias). After a description of the physical phenomena responsible for the oxide-trapped charge evolution, we present the RICN annealing and their implications on devices selection in a radiative environment. The tests describes in this study were performed on SRAMs and on a set of CMOS inverts from three manufacturers. In the last section, we compare our analytical model of RICN annealing with experimental data. (authors)

  19. Evaluation of arctic broadband surface radiation measurements

    OpenAIRE

    N. Matsui; C. N. Long; Augustine, J.; D. Halliwell; T. Uttal; Longenecker, D.; O. Nievergall; Wendell, J.; Albee, R.

    2011-01-01

    The Arctic is a challenging environment for making in-situ radiation measurements. A standard suite of radiation sensors is typically designed to measure the total, direct and diffuse components of incoming and outgoing broadband shortwave (SW) and broadband thermal infrared, or longwave (LW) radiation. Enhancements can include various sensors for measuring irradiance in various narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are...

  20. Evaluation of Arctic broadband surface radiation measurements

    OpenAIRE

    N. Matsui; C. N. Long; Augustine, J.; D. Halliwell; T. Uttal; Longenecker, D.; Niebergall, O.; Wendell, J.; Albee, R.

    2012-01-01

    The Arctic is a challenging environment for making in-situ surface radiation measurements. A standard suite of radiation sensors is typically designed to measure incoming and outgoing shortwave (SW) and thermal infrared, or longwave (LW), radiation. Enhancements may include various sensors for measuring irradiance in narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are mounted on complex mechanical platforms (solar trackers) that ...

  1. Radiation-Tolerant Vertical-Cavity Amplifying Detectors for Time-of-Flight Laser Rangefinders Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The harsh radiation environment anticipated during the Europa Jupiter System Mission (EJSM) presents a significant challenge to develop radiation-hardened notional...

  2. Space radiation protection issues.

    Science.gov (United States)

    Kronenberg, Amy; Cucinotta, Francis A

    2012-11-01

    The complex charged particle environments in space pose considerable challenges with regard to potential health consequences that can impact mission design and crew selection. The lack of knowledge of the biological effects of different ions in isolation and in combination is a particular concern because the risk uncertainties are very high for both cancer and non-cancer late effects. Reducing the uncertainties is of high priority. Two principal components of space radiation each raise different concerns. Solar particle events (SPE) occur sporadically and are comprised primarily of low- to moderate-energy protons. Galactic cosmic radiation (GCR) is isotropic and relatively invariant in dose rate. GCR is also dominated by protons, but the energy range is wider than in SPE. In addition, the contribution of other light and heavy ions to the health risks from GCR must be addressed. This paper will introduce the principal issues under consideration for space radiation protection.

  3. Impact of radiation on breakdown performance of Si strip detectors

    CERN Document Server

    Bhardwaj, A; Chatterji, S; Ranjan, Kirti; Shivpuri, E K; Srivastava-Ajay, K

    2002-01-01

    The very intense radiation environment of high luminosity future colliding beam experiments, like Large Hadron Collider (LHC etc.) makes radiation hardness the most urgent demand for Si detectors. The radiation hardness of Si strip detectors especially developed for LHC experiment was investigated with respect to ionizing and nonionizing radiation using computer simulations. (10 refs).

  4. Ultraviolet radiation in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Taalas, P.; Koskela, T.; Damski, J.; Supperi, A. [Finnish Meteorological Inst., Helsinki (Finland). Section of Ozone and UV Research; Kyroe, E. [Finnish Meteorological Inst., Sodankylae (Finland). Sodankylae Observatory

    1996-12-31

    Solar ultraviolet radiation is damaging for living organisms due to its high energy pro each photon. The UV radiation is often separated into three regions according to the wavelength: UVC (200-280 nm), UVB (280-320 nm) and UVA (320-400 nm). The most hazardous part, UVC is absorbed completely in the upper atmosphere by molecular oxygen. UVB radiation is absorbed by atmospheric ozone partly, and it is reaching Earth`s surface, as UVA radiation. Besides atmospheric ozone, very important factors in determining the intensity of UVB radiation globally are the solar zenith angle and cloudiness. It may be calculated from global ozone changes that the clear-sky UVB doses may have enhanced by 10-15 % during spring and 5-10 % during summer at the latitudes of Finland, following the decrease of total ozone between 1979-90. The Finnish ozone and UV monitoring activities have become a part of international activities, especially the EU Environment and Climate Programme`s research projects. The main national level effort has been the Finnish Academy`s climatic change programme, SILMU 1990-95. This presentation summarises the scientific results reached during the SILMU project

  5. Radiation Hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Castor, J I

    2003-10-16

    The discipline of radiation hydrodynamics is the branch of hydrodynamics in which the moving fluid absorbs and emits electromagnetic radiation, and in so doing modifies its dynamical behavior. That is, the net gain or loss of energy by parcels of the fluid material through absorption or emission of radiation are sufficient to change the pressure of the material, and therefore change its motion; alternatively, the net momentum exchange between radiation and matter may alter the motion of the matter directly. Ignoring the radiation contributions to energy and momentum will give a wrong prediction of the hydrodynamic motion when the correct description is radiation hydrodynamics. Of course, there are circumstances when a large quantity of radiation is present, yet can be ignored without causing the model to be in error. This happens when radiation from an exterior source streams through the problem, but the latter is so transparent that the energy and momentum coupling is negligible. Everything we say about radiation hydrodynamics applies equally well to neutrinos and photons (apart from the Einstein relations, specific to bosons), but in almost every area of astrophysics neutrino hydrodynamics is ignored, simply because the systems are exceedingly transparent to neutrinos, even though the energy flux in neutrinos may be substantial. Another place where we can do ''radiation hydrodynamics'' without using any sophisticated theory is deep within stars or other bodies, where the material is so opaque to the radiation that the mean free path of photons is entirely negligible compared with the size of the system, the distance over which any fluid quantity varies, and so on. In this case we can suppose that the radiation is in equilibrium with the matter locally, and its energy, pressure and momentum can be lumped in with those of the rest of the fluid. That is, it is no more necessary to distinguish photons from atoms, nuclei and electrons, than it is

  6. Radiation Exposure

    Science.gov (United States)

    ... on to any children you have after the exposure. A lot of radiation over a short period, ... skin burns and reduced organ function. If the exposure is large enough, it can cause premature aging ...

  7. Radiation damage

    CERN Document Server

    Heijne, Erik H M; CERN. Geneva

    1998-01-01

    a) Radiation damage in organic materials. This series of lectures will give an overview of radiation effects on materials and components frequently used in accelerator engineering and experiments. Basic degradation phenomena will be presented for organic materials with comprehensive damage threshold doses for commonly used rubbers, thermoplastics, thermosets and composite materials. Some indications will be given for glass, scintillators and optical fibres. b) Radiation effects in semiconductor materials and devices. The major part of the time will be devoted to treat radiation effects in semiconductor sensors and the associated electronics, in particular displacement damage, interface and single event phenomena. Evaluation methods and practical aspects will be shown. Strategies will be developed for the survival of the materials under the expected environmental conditions of the LHC machine and detectors. I will describe profound revolution in our understanding of black holes and their relation to quantum me...

  8. Radiation Transport

    Energy Technology Data Exchange (ETDEWEB)

    Urbatsch, Todd James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-06-15

    We present an overview of radiation transport, covering terminology, blackbody raditation, opacities, Boltzmann transport theory, approximations to the transport equation. Next we introduce several transport methods. We present a section on Caseology, observing transport boundary layers. We briefly broach topics of software development, including verification and validation, and we close with a section on high energy-density experiments that highlight and support radiation transport.

  9. Radiation Protection

    Energy Technology Data Exchange (ETDEWEB)

    Loos, M

    2001-04-01

    Major achievements of SCK-CEN's Radiation Protection Department in 2000 are described. The main areas for R and D of the department remain neutron dosimetry and neutron activation analysis, safeguards information handling and non-destructive assay techniques. Further activities include low-level radioactivity measurements in environmental and biological samples and radiation protection research. Finally, achievements in decision strategy research and social sciences in nuclear research are reported.

  10. Radiation Hardness Assurance for Space Systems

    Science.gov (United States)

    Poivey, Christian; Day, John H. (Technical Monitor)

    2002-01-01

    The space radiation environment can lead to extremely harsh operating conditions for on-board electronic box and systems. The characteristics of the radiation environment are highly dependent on the type of mission (date, duration and orbit). Radiation accelerates the aging of the electronic parts and material and can lead to a degradation of electrical performance; it can also create transient phenomena on parts. Such damage at the part level can induce damage or functional failure at electronic box, subsystem, and system levels. A rigorous methodology is needed to ensure that the radiation environment does not compromise the functionality and performance of the electronics during the system life. This methodology is called hardness assurance. It consists of those activities undertaken to ensure that the electronic piece parts placed in the space system perform to their design specifications after exposure to the space environment. It deals with system requirements, environmental definitions, part selection, part testing, shielding and radiation tolerant design. All these elements should play together in order to produce a system tolerant to.the radiation environment. An overview of the different steps of a space system hardness assurance program is given in section 2. In order to define the mission radiation specifications and compare these requirements to radiation test data, a detailed knowledge of the space environment and the corresponding electronic device failure mechanisms is required. The presentation by J. Mazur deals with the Earth space radiation environment as well as the internal environment of a spacecraft. The presentation by J. Schwank deals with ionization effects, and the presentation by T. Weatherford deals with Single particle Event Phenomena (SEP) in semiconductor devices and microcircuits. These three presentations provide more detailed background to complement the sections 3 and 4. Part selection and categorization are discussed in section

  11. Radiation dosimetry onboard the International Space Station ISS.

    Science.gov (United States)

    Berger, Thomas

    2008-01-01

    Besides the effects of the microgravity environment, and the psychological and psychosocial problems encountered in confined spaces, radiation is the main health detriment for long duration human space missions. The radiation environment encountered in space differs in nature from that on earth, consisting mostly of high energetic ions from protons up to iron, resulting in radiation levels far exceeding the ones encountered on earth for occupational radiation workers. Therefore the determination and the control of the radiation load on astronauts is a moral obligation of the space faring nations. The requirements for radiation detectors in space are very different to that on earth. Limitations in mass, power consumption and the complex nature of the space radiation environment define and limit the overall construction of radiation detectors. Radiation dosimetry onboard the International Space Station (ISS) is onboard the International Space Station (ISS) is accomplished to one part as "operational" dosimetry accomplished to one part as "operational" dosimetry aiming for area monitoring of the radiation environment as well as astronaut surveillance. Another part focuses on "scientific" dosimetry aiming for a better understanding of the radiation environment and its constitutes. Various research activities for a more detailed quantification of the radiation environment as well as its distribution in and outside the space station have been accomplished in the last years onboard the ISS. The paper will focus on the current radiation detectors onboard the ISS, their results, as well as on future planned activities.

  12. Bistability in radiative heat exchange

    Science.gov (United States)

    Rudakov, V. I.; Ovcharov, V. V.; Prigara, V. P.

    2008-08-01

    The possibility of a bistable regime in systems with radiative heat exchange is theoretically demonstrated for the first time. The transfer characteristics of a radiation-closed stationary system have been calculated, in which the radiator is a blackbody and the absorber is made of a material with the absorptivity sharply increasing in a certain temperature interval. The radiator and absorber are separated by a vacuum gap. The heat exchange between the system and the environment is controlled by varying the flow rate of a heat-transfer agent cooling the absorber. The output parameter of a bistable system is the absorber temperature, while the input parameter can be either the radiator temperature or the heat-transfer agent flow rate. Depending on the choice of the input parameter, the transfer characteristic of the system is either represented by a usual S-like curve or has an inverted shape.

  13. Radiation Protection and Architecture Utilizing High Temperature Superconducting Magnets Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Active radiation shielding concepts have been studied for many decades as a means to protect crew from deep space radiation environments. These studies yield...

  14. Synchrotron radiation with radiation reaction

    Science.gov (United States)

    Nelson, Robert W.; Wasserman, Ira

    1991-04-01

    A rigorous discussion is presented of the classical motion of a relativistic electron in a magnetic field and the resulting electromagnetic radiation when radiation reaction is important. In particular, for an electron injected with initial energy gamma(0), a systematic perturbative solution to the Lorentz-Dirac equation of motion is developed for field strengths satisfying gamma(0) B much less than 6 x 10 to the 15th G. A particularly accurate solution to the electron orbital motion in this regime is found and it is demonstrated how lowest-order corrections can be calculated. It is shown that the total energy-loss rate corresponds to what would be found using the exact Larmor power formula without including radiation reaction. Provided that the particle energy and field strength satisfy the same contraint, it is explicitly demonstrated that the intuitive prescription for calculating the time-integrated radiation spectrum described above is correct.

  15. Abdominal radiation - discharge

    Science.gov (United States)

    Radiation - abdomen - discharge; Cancer - abdominal radiation; Lymphoma - abdominal radiation ... When you have radiation treatment for cancer, your body goes through changes. About 2 weeks after radiation treatment starts, you might notice changes ...

  16. Brain radiation - discharge

    Science.gov (United States)

    Radiation - brain - discharge; Cancer-brain radiation; Lymphoma - brain radiation; Leukemia - brain radiation ... Decadron) while you are getting radiation to the brain. It may make you hungrier, cause leg swelling ...

  17. Environment scattering in GADRAS.

    Energy Technology Data Exchange (ETDEWEB)

    Thoreson, Gregory G.; Mitchell, Dean J; Theisen, Lisa Anne; Harding, Lee T.

    2013-09-01

    Radiation transport calculations were performed to compute the angular tallies for scattered gamma-rays as a function of distance, height, and environment. Greens Functions were then used to encapsulate the results a reusable transformation function. The calculations represent the transport of photons throughout scattering surfaces that surround sources and detectors, such as the ground and walls. Utilization of these calculations in GADRAS (Gamma Detector Response and Analysis Software) enables accurate computation of environmental scattering for a variety of environments and source configurations. This capability, which agrees well with numerous experimental benchmark measurements, is now deployed with GADRAS Version 18.2 as the basis for the computation of scattered radiation.

  18. Indirect solar loading of waste heat radiators

    Energy Technology Data Exchange (ETDEWEB)

    Kirkpatrick, R.C.; Tabor, J.E.; Lindman, E.L.; Cooper, A.J.

    1988-01-01

    Waste heat from space based power systems must ultimately be radiated away into space. The local topology around the radiators must be considered from two stand-points: the scattering of sunlight onto the surfaces of the radiator and the heat load that the radiator may put on near-by components of the system. A view factor code (SNAP) developed at Los Alamos allows the computation of the steady-state radiation environment for complex 3-D geometries. An example of the code's utility is given. 4 refs., 2 figs., 1 tab.

  19. Modeling of the radiative field in complex geometries using computerized graphical tools. Application to comfort characterization in environments equipped with important radiative sources; Modelisation du champ radiatif dans des geometries complexes a l`aide d`outils infographiques. Application a la caracterisation du confort dans les ambiances munies de sources radiatives importantes

    Energy Technology Data Exchange (ETDEWEB)

    Manolescu, M.; Sperandio, M.; Allard, F. [La Rochelle Universite, 17 - La Rochelle, LEPTAB (France)

    1996-12-31

    Bibliographic studies in the domain of radiant heat transfers in complex geometries demonstrate the impossibility of resolving such problems using classical analytical methods. The numerical analysis can theoretically be performed successfully but requires enormous computer means. The contribution of this study consists in using computerized graphical techniques to treat general problems of radiant heat transfers in complex geometries. This paper presents the model used, the calculation technique and the optimizations that allow to greatly reduce the computer memory required and the calculation time. The code developed uses evocative images for the synthetic presentation of results which facilitate the searcher`s and conceiver`s choices. Finally, an application to the characterization of thermal comfort in residential environments is developed to illustrate the potentialities of this method. (J.S.) 19 refs.

  20. Directional radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Dowell, Jonathan L.

    2017-09-12

    Directional radiation detectors and systems, methods, and computer-readable media for using directional radiation detectors to locate a radiation source are provided herein. A directional radiation detector includes a radiation sensor. A radiation attenuator partially surrounds the radiation sensor and defines an aperture through which incident radiation is received by the radiation sensor. The aperture is positioned such that when incident radiation is received directly through the aperture and by the radiation sensor, a source of the incident radiation is located within a solid angle defined by the aperture. The radiation sensor senses at least one of alpha particles, beta particles, gamma particles, or neutrons.

  1. Radiation characterization summary :

    Energy Technology Data Exchange (ETDEWEB)

    Parma, Edward J.,; Quirk, Thomas J.; Lippert, Lance L.; Griffin, Patrick J; Naranjo, Gerald E.; Luker, Spencer Michael

    2013-04-01

    This document presents the facility-recommended characterization of the neutron, prompt gamma-ray, and delayed gamma-ray radiation fields in the Annular Core Research Reactor (ACRR) for the 44-inch-long lead-boron bucket in the central cavity on the 32-inch pedestal at the core centerline. The designation for this environment is ACRR-LB44-CC-32-cl. The neutron, prompt gamma-ray, and delayed gamma-ray energy spectra are presented as well as radial and axial neutron and gamma-ray flux profiles within the experiment area of the bucket. Recommended constants are given to facilitate the conversion of various dosimetry readings into radiation metrics desired by experimenters. Representative pulse and steady-state operations are presented with conversion examples.

  2. HANARO radiation emergency plan

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Tai

    1997-10-15

    The emergency plan of HANARO (High-flux advanced Neutron Application Reactor) is prepared based on the Korea Atomic Law, the Civil Defence Law, Disaster Protection Law and the emergency related regulation guides such as the NUREG series from USNRC to ensure adequate response capabilities to the emergency event which would cause a significant risk to the KAERI staffs and the public near to the site. Periodic training and exercise for the reactor operators and emergency staffs will reduce accident risks and the release of radioactivities to the environment. The plan describes the organization and staff's duties in the radiation emergency, classification on the radiation accidents, urgent actions of reactor operators in the early state, emergency response activities, maintenance of emergency equipment, training and exercise to improve response capabilities against emergency accidents. (author). 1 tab., 5 figs.

  3. Cherenkov radiation; La radiation Cerenkov

    Energy Technology Data Exchange (ETDEWEB)

    Hubert, P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    When the radioactivity has been discovered, it was observed by researchers that different materials as mineral salts or solutions were emitting a weak light when submitted to radioactivity beams. At the beginning it has been thought that it was fluorescent light. In 1934, Cherenkov, a russian physicist, worked on the luminescence of uranyl salts solutions caused by gamma radiation and observed a very weak light was emitted by pure liquid. After further studies, he concluded that this phenomena was different from fluorescence. Since then, it has been called Cherenkov effect. This blue light emission is produced when charged particles are going through a transparent medium with an upper velocity than light velocity. This can happen only in medium with large refractive index as water or glass. It also presents its different properties discovered afterwards. The different applications of the Cherenkov radiation are discussed as counting techniques for radiation detectors or comic ray detectors. (M.P.)

  4. Behaviour of circuits with respect to ionising radiations; Tenue des circuits aux radiations ionisantes

    Energy Technology Data Exchange (ETDEWEB)

    Boudenot, J.C. [Thomson-CSF, 75 - Paris (France)

    1999-11-01

    Electronic components with a greater integration of transistors, with an increase of surface and with reduced grid distances and operating voltages are more and more developing. These new technologies are more sensible to radiative environments which can lead to important disturbances: multiple upset, low level leakage current in MOS components etc.. The hardening techniques used so far must be adapted in order to take into account these new phenomena. This paper deals successively with: 1 - recall about radiations: interaction with matter (electrons, protons, heavy ions, photons, neutrons), effects to be considered (dose and dose rates, displacements, linear energy transfer and critical load); 2 - radiative environments: nuclear explosions, spatial environment (radiation belts, solar eruptions and wind, cosmic radiation), atmospheric environment, other environments (particle accelerators, robots in radiative environments, nuclear power plants, propulsion reactors, fusion devices, dismantling of nuclear facilities, industrial irradiations); 3 - radiative effects and technological hardening: cumulated dose (basic mechanisms, influence of radiation, polarization, dose rates, temperature, process, vulnerability of components), neutron fluence, heavy ions; 4 - protection means: components technology, circuits and systems (dose and dose rates, neutrons, heavy ions), hardening strategy; 5 - hardening validation: testing methods and procedures, nuclear hardening assurance (context, definition of needs, distribution of afterlife probabilities, design margins, components classification, repertory file), space hardening assurance (context, dose effects, direct and indirect heavy ion effects, assurance costs). (J.S.)

  5. Radiation Technology Against Bioterrorism

    Science.gov (United States)

    2004-10-25

    application of radiation processing: radiation crosslinking of polymers and radiation sterilization of health care products have developed into substantial...municipal waste water, • radiation inactivation of bioterrorism agents, • electron beam processing of flue gases, • radiation crosslinking , • radiation...Electron beam processing of flue gases 6. Radiation crosslinking 7. Radiation curing 3 Radiation Technology Against Bioterrorism L.G. Gazsó and G

  6. Physics and engineering of radiation detection

    CERN Document Server

    Ahmed, Syed Naeem

    2015-01-01

    Physics and Engineering of Radiation Detection presents an overview of the physics of radiation detection and its applications. It covers the origins and properties of different kinds of ionizing radiation, their detection and measurement, and the procedures used to protect people and the environment from their potentially harmful effects. The second edition is fully revised and provides the latest developments in detector technology and analyses software. Also, more material related to measurements in particle physics and a complete solutions manual have been added.

  7. Radiation Tolerant Software Defined Video Processor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MaXentric's is proposing a radiation tolerant Software Define Video Processor, codenamed SDVP, for the problem of advanced motion imaging in the space environment....

  8. Radiation Mitigation Methods for Reprogrammable FPGA Project

    Data.gov (United States)

    National Aeronautics and Space Administration — One of the needs of NASA is the development of avionic systems and components that have the capability to operate in extreme radiation and temperature environments...

  9. WAVS radiation shielding references and assumptions

    Energy Technology Data Exchange (ETDEWEB)

    McLean, Adam [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-07

    At ITER, the confluence of a high radiation environment and the requirement for high performance imaging for plasma and plasma-facing surface diagnosis will necessitate extensive application of radiation shielding. Recommended here is a dual-layer shield design composed of lead for gamma attenuation, surrounded by a fire-resistant polyehtylene doped with a thermal neutron absorber for neutron shielding.

  10. Radiation Effects in Carbon Nanoelectronics

    Directory of Open Access Journals (Sweden)

    Cory D. Cress

    2012-07-01

    Full Text Available We experimentally investigate the effects of Co-60 irradiation on the electrical properties of single-walled carbon nanotube and graphene field-effect transistors. We observe significant differences in the radiation response of devices depending on their irradiation environment, and confirm that, under controlled conditions, standard dielectric hardening approaches are applicable to carbon nanoelectronics devices.

  11. Optimization and radiation protection culture

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, In Young; Shin, Hyeong Ki; Lee, Chan Mi [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2013-04-15

    Safety culture or radiation protection culture is based in common on the term, 'culture'. Culture is defined as the learned, shared set of symbols and patterns of basic assumptions, which is invented, discovered, or developed by a given group as it learns to cope with its problem of external adaptation and internal integration. Safety culture generally refers to the attitude and behaviors affecting safety performance. The concept of 'Safety Culture' was introduced after the Chernobyl accident in 1986. For the accident, nuclear society reached the conclusion that the cause was the wrong management attitude of the NPP, that is, deficient 'Safety Culture'. Recently, 'Radiation Protection Culture' was introduced as the core concept of nuclear safety culture. There have been many efforts to establish definition and develop assessment tool for radiation protection culture in international level such as ICRP and IRPA as well as NRC. In the same context with the safety culture, radiation protection culture is defined as 'the core values and behaviors resulting from a collective commitment by leaders and individual's to emphasize safety over competing goals to ensure protection of people and the environment.' It is worthwhile to recognize that regulatory enforcement in establishing healthy radiation protection culture of operators should be minimized because culture is not in the domain of regulatory enforcement. However, as 'ALARA', the most important concept in radiation protection, may be successfully achieved only in well established radiation protection culture, the least regulatory intervention would be needed in promoting and nurturing radiation protection culture in licensee. In addition, the concept of radiation protection culture should be addressed in plant operational policy to achieve the goals of ALARA. The pre-condition of the successful radiation protection culture is a healthy organizational

  12. The LISA Pathfinder Radiation Monitor

    Science.gov (United States)

    Wass, P. J.; Araújo, H.; Boatella, C.; Chmeissani, M.; Hajdas, W.; Lobo, A.; Puigdengoles, C.; Sumner, T.

    2006-11-01

    We present the concept, design and testing of the radiation monitor for LISA Pathfinder. Galactic cosmic rays (GCRs) and solar energetic particles (SEPs) will cause charging of the LISA Pathfinder test masses producing unwanted disturbances which could be significant during a large solar eruption. A radiation monitor on board LISA Pathfinder, using silicon PIN diodes as particle detectors, will measure the particle flux responsible for charging. It will also be able to record spectral information to identify solar energetic particle events. The design of the monitor was supported by Monte Carlo simulations which allow detailed predictions of the radiation monitor performance. We present these predictions as well as the results of high-energy proton tests carried out at the Paul Scherrer Institute, Switzerland. The tests show good agreement with our simulations and confirm the capability of the radiation monitor to perform well in the space environment, meeting all science requirements.

  13. 电子辐射环境中NPN输入双极运算放大器的辐射效应和退火特性%Radiation damage effect and p ost-annealing treatments of NPN-input bip olar op erational amplifier in electron radiation environment

    Institute of Scientific and Technical Information of China (English)

    姜柯; 陆妩; 胡天乐; 王信; 郭旗; 何承发; 刘默涵; 李小龙

    2015-01-01

    With the rapid development of the space technology, operational amplifier is widely used as the basic liner circuit in a satellite system. There are many charged particles trapped in the earth’s magnetosphere, most of the particles are protons and electrons. In BJTs, the damage caused by electrons causes both bulk recombination and surface recombination to increase and subsequently current gain to decrease. Transistor gain degradation is the primary cause of parametric shifts and functional failures in linear bipolar circuits. The severity of electron radiation response correlates with electron’s energy and flux, therefore it is important to understand the electron radiation response in different conditions. In this paper, the tested devices used in this study are NPN-input bipolar operational amplifiers commercial-off-the-shelf (COTS) manufactured by Texas Instruments (TI). NPN-input bipolar operational amplifiers LM108 are irradiated with different energy and different beam current electrons respectively under different bias conditions to study the electron radiation damage effect. Experiment using 60Coγ-ray radiation is conducted to compare the different radiation damages between 60Co γ-ray and electron radiation. The total radiation experiments are carried out with the 60Coγ-ray source (Xinjiang Technical Institute of physics and chemistry). The radiation dose rates for the test samples are 1 Gy (Si)/s, and the total accumulated dose is 1000 Gy (Si). Subsequently, room temperature and high temperature annealings are conducted to analyze the parametric failure mechanism of LM108 caused by a total dose radiation for different biases. Result shows that 0.32 Gy(Si)/s beam current electrons can induce more damage than that caused by 1.53 Gy(Si)/s electrons with the same energy;1.8 MeV electrons can induce more damages than 1 MeV electrons with the same electron beam current because the former produces more displacement damage than the latter. Comparison

  14. Meeting Report--NASA Radiation Biomarker Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Straume, Tore; Amundson, Sally A,; Blakely, William F.; Burns, Frederic J.; Chen, Allen; Dainiak, Nicholas; Franklin, Stephen; Leary, Julie A.; Loftus, David J.; Morgan, William F.; Pellmar, Terry C.; Stolc, Viktor; Turteltaub, Kenneth W.; Vaughan, Andrew T.; Vijayakumar, Srinivasan; Wyrobek, Andrew J.

    2008-05-01

    A summary is provided of presentations and discussions from the NASA Radiation Biomarker Workshop held September 27-28, 2007, at NASA Ames Research Center in Mountain View, California. Invited speakers were distinguished scientists representing key sectors of the radiation research community. Speakers addressed recent developments in the biomarker and biotechnology fields that may provide new opportunities for health-related assessment of radiation-exposed individuals, including for long-duration space travel. Topics discussed include the space radiation environment, biomarkers of radiation sensitivity and individual susceptibility, molecular signatures of low-dose responses, multivariate analysis of gene expression, biomarkers in biodefense, biomarkers in radiation oncology, biomarkers and triage following large-scale radiological incidents, integrated and multiple biomarker approaches, advances in whole-genome tiling arrays, advances in mass-spectrometry proteomics, radiation biodosimetry for estimation of cancer risk in a rat skin model, and confounding factors. Summary conclusions are provided at the end of the report.

  15. DOE 2013 occupational radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2014-11-01

    The Office of Analysis within the U.S. Department of Energy (DOE) Office of Environment, Health, Safety and Security (EHSS) publishes the annual DOE Occupational Radiation Exposure Report to provide an overview of the status of radiation protection practices at DOE (including the National Nuclear Security Administration [NNSA]). The DOE 2013 Occupational Radiation Exposure Report provides an evaluation of DOE-wide performance regarding compliance with Title 10, Code of Federal Regulations (C.F.R.), Part 835, Occupational Radiation Protection dose limits and as low as reasonably achievable (ALARA) process requirements. In addition, the report provides data to DOE organizations responsible for developing policies for protection of individuals from the adverse health effects of radiation. The report provides a summary and an analysis of occupational radiation exposure information from the monitoring of individuals involved in DOE activities. Over the past five-year period, the occupational radiation exposure information has been analyzed in terms of aggregate data, dose to individuals, and dose by site.

  16. Space Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Corliss, William R.

    1968-01-01

    This booklet discusses three kinds of space radiation, cosmic rays, Van Allen Belts, and solar plasma. Cosmic rays are penetrating particles that we cannot see, hear or feel, which come from distant stars. Van Allen Belts, named after their discoverer are great belts of protons and electrons that the earth has captured in its magnetic trap. Solar plasma is a gaseous, electrically neutral mixture of positive and negative ions that the sun spews out from convulsed regions on its surface.

  17. Radiation protection

    CERN Multimedia

    Radioactive Shipping Service

    2005-01-01

    The section of the radiation protection group in charge of shipping radioactive material would like to remind users that all radioactive material leaving CERN must be checked for radioactivity and must be shipped according to the procedure given at http://cern.ch/service-rp-shipping Do not hesitate to contact us for any question or control. Radioactive Shipping Service: service-rp-shipping@cern.ch Tél. 73171

  18. Radiation protection

    CERN Document Server

    2005-01-01

    The section of the Radiation Protection Group in charge of shipping radioactive material would like to remind users that all radioactive material leaving CERN must be checked for radioactivity and must be shipped according to the procedure given at http://cern.ch/service-rp-shipping Do not hesitate to contact us for any question or control. Radioactive Shipping Service: service-rp-shipping@cern.ch Tel. 73171

  19. Radiation protection

    CERN Multimedia

    2005-01-01

    The section of the Radiation Protection Group in charge of shipping radioactive material would like to remind users that all radioactive material leaving CERN must be checked for radioactivity and must be shipped according to the procedure given at http://cern.ch/service-rp-shipping Do not hesitate to contact us for any question or control. Radioactive Shipping Service: service-rp-shipping@cern.ch Tél. 73171

  20. Radiatively Generated $\

    CERN Document Server

    Joshipura, A S; Joshipura, Anjan S.; Rindani, Saurabh D.

    2003-01-01

    We study the consequences of assuming that the mass scale $\\Delta_{odot}$ corresponding to the solar neutrino oscillations and mixing angle $U_{e3}$ corresponding to the electron neutrino oscillation at CHOOZ are radiatively generated through the standard electroweak gauge interactions. All the leptonic mass matrices having zero $\\Delta_{odot}$ and $U_{e3}$ at a high scale lead to a unique low energy value for the $\\Delta_{odot}$ which is determined by the (known) size of the radiative corrections, solar and the atmospheric mixing angle and the Majorana mass of the neutrino observed in neutrinoless double beta decay. This prediction leads to the following consequences: ($i$) The MSSM radiative corrections generate only the dark side of the solar neutrino solutions. ($ii$) The inverted mass hierarchy ($m,-m,0$) at the high scale fails in generating the LMA solution but it can lead to the LOW or vacuum solutions. ($iii$) The $\\Delta_{odot}$ generated in models with maximal solar mixing at a high scale is zero t...

  1. Polonium-210 and other radionuclides in terrestrial, freshwater and brackish environments Results from the NKS project GAPRAD (Filling knowledge gaps in radiation protection methodologies for non-human biota)

    Energy Technology Data Exchange (ETDEWEB)

    Gjelsvik, R.; Brown, J.; Holm, E.; Roos, P.; Saxen, R.; Outola, I.

    2012-01-15

    The background and rationale to filling knowledge gaps in radiation protection methodologies for biota are presented. Concentrations of Po-210 and Pb-210 are reported for biota sampled in Dovrefjell, Norway and selected lake and brackish ecosystems in Finland. Furthermore, details in relation to Po-210 uptake and biokinetics in humans based on experimental studies are recounted. (Author)

  2. Acute Radiation Syndrome

    Science.gov (United States)

    ... Matters Information on Specific Types of Emergencies Acute Radiation Syndrome (ARS): A Fact Sheet for the Public ... is called the radiation dose. People exposed to radiation will get ARS only if: The radiation dose ...

  3. Chest radiation - discharge

    Science.gov (United States)

    Radiation - chest - discharge; Cancer - chest radiation; Lymphoma - chest radiation ... When you have radiation treatment for cancer, your body goes through changes. About 2 weeks after your first treatment: It may be hard ...

  4. Risk Factors: Radiation

    Science.gov (United States)

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

  5. Ergonomics in the office environment

    Science.gov (United States)

    Courtney, Theodore K.

    1993-01-01

    Perhaps the four most popular 'ergonomic' office culprits are: (1) the computer or visual display terminal (VDT); (2) the office chair; (3) the workstation; and (4) other automated equipment such as the facsimile machine, photocopier, etc. Among the ergonomics issues in the office environment are visual fatigue, musculoskeletal disorders, and radiation/electromagnetic (VLF,ELF) field exposure from VDT's. We address each of these in turn and then review some regulatory considerations regarding such stressors in the office and general industrial environment.

  6. Endophytic fungi of the Genus Penicillium isolated of Platypodium elegans from environments of high dose rate of ionizing radiation; Fungos endofiticos do genero Penicillium isolados de Platypodium elegans provenientes de locais de alta taxa de radiacao

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Victor da

    1999-07-01

    The present work had as objective to isolate and to identify endophytic microorganisms and were exposed to stress situations, using for this ionizing radiations, these highly mutagen and in high doses, lethal to all the alive organisms. The endophytic microorganisms were obtained the starting from the species arboreal Platypodium elegans Vog., one of them developed in radioactive land in the area of Ipora/Go and other, developed in land Background in the city of Abadia de Goias/GO. The rates of dose of environmental radiation were shown sharply different, being in Ipora (Anomaly 2) with a value of approximately 140 {mu}R/h and in Abadia de Goias with approximately 20 {mu}R/H, both measured the area of root of the tree close to. Tests through PCR-RAPD were accomplished with the isolated ones, for verification of the similarity of its genetic characteristics and possible polymorphism among its DNA's . The isolated ones were studied with relationship to the effects of the gamma radiation, being used as source {sup 60} Co, with doses of 25 to 2131 Gy. These lineages had the same behavior practically with relationship to the resistance of the gamma radiation, declining strongly at levels of approximately 700 Gy. The isolated ones tested were identified at microscope for morphology, being of the Genus Penicillium, with the same genetic characteristics in agreement with PCR/RAPD, being just observed a polymorphism area in its DNA's. In spite of a lineage to have been isolated of a tree developed in radioactive land, any difference was observed among its resistance to the gamma radiation in comparison to the isolated lineage of tree developed in land radiometric background. (author)

  7. Proceedings of the Conference and Symposium Korean Association for Radiation Protection Spring Meeting 2015

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-04-15

    This proceedings contains articles of the Korean Association for Radiation Protection Spring Meeting, 2015. It was held on Apr. 22-24, 2015 in Yeosu, Korea and subject of the Korean Association for Radiation Protection Spring Meeting 2014. This proceedings is comprised of 8 sessions. The main topic titles of session are as follows: Radiation protection 1, Medical treatment and Biology 1, Radiation Measurement 1, Radiation environment and disasters prevention 1, Radiation protection 2, Medical treatment and Biology 2, Radiation Measurement 2, Radiation environment and disasters prevention 2.

  8. Proceedings of the Conference and Symposium Korean Association for Radiation Protection Fall Meeting 2014

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2014-11-15

    This proceedings contains articles of the Korean Association for Radiation Protection Fall Meeting, 2014. It was held on Nov.19-21, 2014 in Jeju, Korea and subject of the Korean Association for Radiation Protection Fall Meeting 2014. This proceedings is comprised of 8 sessions. The main topic titles of session are as follows: Radiation protection 1, Medical treatment and Biology 1, Radiation measurement 1, Radiation environment and protection 1, Radiation protection 2, Medical treatment and Biology 2, Radiation Measurement 2, Radiation environment and protection 2.

  9. Proceedings of the Conference and Symposium Korean Association for Radiation Protection Fall Meeting 2015

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-10-15

    This proceedings contains articles of the Korean Association for Radiation Protection Fall Meeting, 2015. It was held on Oct.23, 2015 Mayfield Hotel in Seoul, Korea and subject of the Korean Association for Radiation Protection Fall Meeting 2015. This proceedings is comprised of 8 sessions. The main topic titles of session are as follows: Radiation protection 1, Medical treatment and Biology 1, Radiation Measurement 1, Radiation environment and disasters prevention 1, Radiation protection 2, Medical treatment and Biology 2, Radiation Measurement 2, Radiation environment and disasters prevention 2.

  10. Silicon solid state devices and radiation detection

    CERN Document Server

    Leroy, Claude

    2012-01-01

    This book addresses the fundamental principles of interaction between radiation and matter, the principles of working and the operation of particle detectors based on silicon solid state devices. It covers a broad scope with respect to the fields of application of radiation detectors based on silicon solid state devices from low to high energy physics experiments including in outer space and in the medical environment. This book covers stateof- the-art detection techniques in the use of radiation detectors based on silicon solid state devices and their readout electronics, including the latest developments on pixelated silicon radiation detector and their application.

  11. Live with radiation from the basics to practice. Proceedings; Leben mit Strahlung - Von den Grundlagen zur Praxis. Tagungsbeitraege

    Energy Technology Data Exchange (ETDEWEB)

    Maringer, Franz Josef; Czarwinski, Renate; Geringer, Thomas; Brandl, Alexander; Steurer, Andreas (eds.)

    2009-07-01

    The conference proceedings of the common radiation protection meeting 2009 in Alpbach, Tyrol include29 papers concerning global safety, 33 papers concerning environment, 18 papers concerning radiation protection in medicine, and 16 papers concerning live with radiation.

  12. Nuclear Energy and the Environment.

    Science.gov (United States)

    International Atomic Energy Agency, Vienna (Austria).

    "Nuclear Energy and the Environment" is a pocket folder of removable leaflets concerned with two major topics: Nuclear energy and Nuclear Techniques. Under Nuclear Energy, leaflets concerning the topics of "Radiation--A Fact of Life,""The Impact of a Fact: 1963 Test Ban Treaty,""Energy Needs and Nuclear Power,""Power Reactor Safety,""Transport,"…

  13. Radiation-induced Genomic Instability and Radiation Sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Varnum, Susan M.; Sowa, Marianne B.; Kim, Grace J.; Morgan, William F.

    2013-01-19

    The obvious relationships between reactive oxygen and nitrogen species, mitochondrial dysfunction, inflammatory type responses and reactive chemokines and cytokines suggests a general stress response induced by ionizing radiation most likely leads to the non-targeted effects described after radiation exposure. We argue that true bystander effects do not occur in the radiation therapy clinic. But there is no question that effects outside the target volume do occur. These “out of field effects” are considered very low dose effects in the context of therapy. So what are the implications of non-targeted effects on radiation sensitivity? The primary goal of therapy is to eradicate the tumor. Given the genetic diversity of the human population, lifestyle and environment factors it is likely some combination of these will influence patient outcome. Non-targeted effects may contribute to a greater or lesser extent. But consider the potential situation involving a partial body exposure due to a radiation accident or radiological terrorism. Non-targeted effects suggest that the tissue at risk for demonstrating possible detrimental effects of radiation exposure might be greater than the volume actually irradiated.

  14. Space radiation and cardiovascular disease risk

    Institute of Scientific and Technical Information of China (English)

    Marjan Boerma; Gregory A Nelson; Vijayalakshmi Sridharan; Xiao-Wen Mao; Igor Koturbash; Martin Hauer-Jensen

    2015-01-01

    Future long-distance space missions will be associated with significant exposures to ionizing radiation,and the health risks of these radiation exposures during manned missions need to be assessed. Recent Earth-based epidemiological studies in survivors of atomic bombs and after occupational and medical low dose radiation exposures have indicated that the cardiovascular system may be more sensitive to ionizing radiation than was previously thought. This has raised the concern of a cardiovascular disease risk from exposure to space radiation during long-distance space travel. Groundbased studies with animal and cell culture models play an important role in estimating health risks from space radiation exposure. Charged particle space radiation has dense ionization characteristics and may induce unique biological responses,appropriate simulation of the space radiation environment and careful consideration of the choice of the experimental model are critical. Recent studies have addressed cardiovascular effects of space radiation using such models and provided first results that aid in estimating cardiovascular disease risk,and several other studies are ongoing. Moreover,astronauts could potentially be administered pharmacological countermeasures against adverse effects of space radiation,and research is focused on the development of such compounds. Because the cardiovascular response to space radiation has not yet been clearly defined,the identification of potential pharmacological countermeasures against cardiovascular effects is still in its infancy.

  15. Space radiation and cardiovascular disease risk.

    Science.gov (United States)

    Boerma, Marjan; Nelson, Gregory A; Sridharan, Vijayalakshmi; Mao, Xiao-Wen; Koturbash, Igor; Hauer-Jensen, Martin

    2015-12-26

    Future long-distance space missions will be associated with significant exposures to ionizing radiation, and the health risks of these radiation exposures during manned missions need to be assessed. Recent Earth-based epidemiological studies in survivors of atomic bombs and after occupational and medical low dose radiation exposures have indicated that the cardiovascular system may be more sensitive to ionizing radiation than was previously thought. This has raised the concern of a cardiovascular disease risk from exposure to space radiation during long-distance space travel. Ground-based studies with animal and cell culture models play an important role in estimating health risks from space radiation exposure. Charged particle space radiation has dense ionization characteristics and may induce unique biological responses, appropriate simulation of the space radiation environment and careful consideration of the choice of the experimental model are critical. Recent studies have addressed cardiovascular effects of space radiation using such models and provided first results that aid in estimating cardiovascular disease risk, and several other studies are ongoing. Moreover, astronauts could potentially be administered pharmacological countermeasures against adverse effects of space radiation, and research is focused on the development of such compounds. Because the cardiovascular response to space radiation has not yet been clearly defined, the identification of potential pharmacological countermeasures against cardiovascular effects is still in its infancy.

  16. Radiation Bystander Effects Mechanism

    Directory of Open Access Journals (Sweden)

    Shokohzaman Soleymanifard

    2009-06-01

    Full Text Available Introduction: Radiation Induced Bystander Effect (RIBE which cause radiation effects in non-irradiated cells, has challenged the principle according to which radiation traversal through the nucleus of a cell is necessary for producing biological responses. What is the mechanism of this phenomenon? To have a better understanding of this rather ambiguous concept substantial number of original and reviewed article were carefully examined. Results: Irradiated cells release molecules which can propagate in cell environment and/or transmit through gap junction intercellular communication. These molecules can reach to non-irradiated cells and transmit bystander signals. In many investigations, it has been confirmed that these molecules are growth factors, cytokines, nitric oxide and free radicals like reactive oxygen species (ROS. Transmission of by stander signal to neighboring cells persuades them to produce secondary growth factors which in their turn cause further cell injuries. Some investigators suggest, organelles other than nucleus (mitochondria and cell membrane are the origin of these signals.  There is another opinion which suggests double strand breaks (DSB are not directly generated in bystander cells, rather they are due to smaller damage like single strand breaks which accumulate and end up to DSB. Although bystander mechanisms have not been exactly known, it can be confirmed that multiple mechanisms and various pathways are responsible for this effect. Cell type, radiation type, experimental conditions and end points identify the dominant mechanism. Conclusion: Molecules and pathways which are responsible for RIBE, also cause systemic responses to other non-irradiation stresses. So RIBE is a kind of systemic stress or innate immune responses, which are performed by cell microenvironment. Irradiated cells and their signals are components of microenvironment for creating bystander effects.

  17. Observing environments

    DEFF Research Database (Denmark)

    Alrøe, Hugo Fjelsted; Noe, Egon

    2012-01-01

    , and analyse how their conceptions of environment are connected to differences of perspective and observation. Results: We show the need to distinguish between inside and outside perspectives on the environment, and identify two very different and complementary logics of observation, the logic of distinction......, and that it is based fully on the conception of observation as indication by means of distinction....

  18. Encapsulated Environment

    NARCIS (Netherlands)

    McLellan, T.M.; Daanen, H.A.M.; Cheung, S.S.

    2013-01-01

    In many occupational settings, clothing must be worn to protect individuals from hazards in their work environment. However, personal protective clothing (PPC) restricts heat exchange with the environment due to high thermal resistance and low water vapor permeability. As a consequence, individuals

  19. Job satisfaction and its relationship to Radiation Protection Knowledge, Attitude and Practice (RPKAP) of Iranian radiation workers.

    Science.gov (United States)

    Alavi, S S; Dabbagh, S T; Abbasi, M; Mehrdad, R

    2017-01-23

    This study aimed to find the association between job satisfaction and radiation protection knowledge, attitude and practice of medical radiation workers occupationally exposed to ionizing radiation. In this crosssectional study, 530 radiation workers affiliated to Tehran University of Medical Sciences completed a knowledge, attitude and practice questionnaire on protecting themselves against radiation and Job Descriptive Index as a job satisfaction measure during May to November 2014. Opportunities for promotion (84.2%) and payment (91.5%) were the most important factors for dissatisfaction. Radiation workers who were married, had more positive attitudes toward protecting themselves against radiation, and had higher level of education accounted for 15.8% of the total variance in predicting job satisfaction. In conclusion, medical radiation workers with a more positive attitude toward self-protection against radiation were more satisfied with their jobs. In radiation environments, improving staff attitudes toward their safety may be considered as a key strategy to increase job satisfaction.

  20. Design of SJ-10 Space Radiation Detector Prototype

    CERN Document Server

    Liu, Yaqing; Cui, Xingzhu; Peng, Wenxi; Fan, Ruirui; Gao, Xiaohua Liang Ming; Zhang, Yunlong; Zhang, Chengmo; Zhang, Jiayu; Yang, Jiawei; Wang, Jinzhou; Dong, Fei Zhang Yifan; Guo, Dongya; Zhou, Dawei

    2014-01-01

    The space radiation detector is a space apparatus for detecting the outer-space particles and monitoring the radiation environment. Though identifying the particles and acquiring the biological experimental data, we can learn about the space radiation impacts on the human body and defend the space radiation damage. This paper designed a prototype of the space radiation detector for SJ-10 and evaluated the performance by the system simulation. More specifically, the space radiation impacts on the human body were analyzed including the different particles, the radiation flux and the energy channels. Then the detector system based on analysis results were built by the Monte Carlo simulation. Finally, the detection algorithms of incident energy range were proposed to identify the outer-space particles and provide the reliable radiation environment data for biological experimental apparatus.