WorldWideScience

Sample records for radiation shielding study

  1. Radiation shield

    Energy Technology Data Exchange (ETDEWEB)

    Nemezawa, Isao; Kimura, Tadahiro [Hitachi Ltd., Tokyo (Japan); Omori, Tetsu; Mizuochi, Akira

    1997-11-18

    A radiation shield is constituted by using a flexible bag made of a synthetic resin, a rubber plate or a composite member of them. Water is charged therein as a shielding liquid. Water injection ports are formed at the lower surface, and gas exhaustion ports are formed on the upper surface of the radiation shield. A plurality of vertical ribs made of the same material as the bag of the radiation shield are formed, integral with the bag, each at a space on the outer surface of the radiation shield. A reinforcing tube are inserted to the vertical ribs integral with the bag. The reinforcing tube may be made of an metal or non-metal material, but material having a bending strength greater than that of the bag is used. When wide surfaces are constituted in the horizontal direction as radiation shielding surfaces, a plurality of the radiation shields are used being in adjacent in the horizontal direction. The reinforcing tubes in adjacent with each other among the adjacent radiation shields are connected by connectors. (I.N.)

  2. Parameter Study for Optimizing the Mass of a Space Nuclear Power System Radiation Shield

    National Research Council Canada - National Science Library

    Kowash, Benjamin

    2002-01-01

    A parameter study was conducted for a space nuclear reactor radiation shield. The focus of this research was to explore alternatives to current radiation shield designs to reduce the mass while maintaining the same shielding performance...

  3. Radiation shielding member

    Energy Technology Data Exchange (ETDEWEB)

    Kasai, Tsutomu

    1998-03-17

    An iron box having optional width, depth and height with no back board is secured to the outer surface of an iron shielding member formed by laminating optional number of iron plates having an optional thickness. Optional number of structural walls acting also as partition walls and comprising a synthetic resin and having a neutron shielding function of a predetermined thickness is disposed between the front plate and the back face of the iron box. Pellets made of a synthetic resin having a radiation shielding function are filled in the iron box. As the synthetic resin having a neutron ray shielding function, a polyethylene resin is preferably used. The radiation shielding member thus constituted is used for a radiation shielding door. Radiation rays irradiated from a chamber are shielded except for neutron rays by the iron shielding member. Neutron rays permeate the iron shielding member, and are shielded by the layers of polyethylene pellets filled in the iron box. (I.N.)

  4. A Radiation shielding study for the Fermilab Linac

    Energy Technology Data Exchange (ETDEWEB)

    Rakhno, I.; Johnstone, C.; /Fermilab

    2006-02-01

    Radiation shielding calculations are performed for the Fermilab Linac enclosure and gallery. The predicted dose rates around the access labyrinth at normal operation and a comparison to measured dose rates are presented. An accident scenario is considered as well.

  5. Radiation Shielding for Fusion Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, R.T.

    1999-10-01

    Radiation shielding requirements for fusion reactors present different problems than those for fission reactors and accelerators. Fusion devices, particularly tokamak reactors, are complicated by geometry constraints that complicate disposition of fully effective shielding. This paper reviews some of these shielding issues and suggested solutions for optimizing the machine and biological shielding. Radiation transport calculations are essential for predicting and confirming the nuclear performance of the reactor and, as such, must be an essential part of the reactor design process. Development and optimization of reactor components from the first wall and primary shielding to the penetrations and containment shielding must be carried out in a sensible progression. Initial results from one-dimensional transport calculations are used for scoping studies and are followed by detailed two- and three-dimensional analyses to effectively characterize the overall radiation environment. These detail model calculations are essential for accounting for the radiation leakage through ports and other penetrations in the bulk shield. Careful analysis of component activation and radiation damage is cardinal for defining remote handling requirements, in-situ replacement of components, and personnel access at specific locations inside the reactor containment vessel. Radiation shielding requirements for fusion reactors present different problems than those for fission reactors and accelerators. Fusion devices, particularly tokamak reactors, are complicated by geometry constraints that complicate disposition of fully effective shielding. This paper reviews some of these shielding issues and suggested solutions for optimizing the machine and biological shielding. Radiation transport calculations are essential for predicting and confirming the nuclear performance of the reactor and, as such, must be an essential part of the reactor design process. Development and optimization of reactor

  6. Preliminary study for development of low dose radiation shielding material using liquid silicon and metallic compound

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Seo Goo; Lee, Sung Soo [Dept. of Medical Science, Graduate School of Soonchunhyang University, Asan (Korea, Republic of); Han, Su Chul [Div. of Medical Radiation Equipment, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Kang, Sung Jin [SoonChunHyang University Hospital, Seoul (Korea, Republic of); Lim, Sung Wook [Graduate school of SeJong University, Seoul (Korea, Republic of)

    2017-09-15

    This study measured and compared the protective clothing using Pb used for shielding in a diagnostic X-ray energy range, and the shielding rates of X-ray fusion shielding materials using Si and TiO{sub 2}. For the experiment, a pad type shielding with a thickness of 1 mm was prepared by mixing Si-TiO{sub 2}, and the X-ray shielding rate was compared with 0.5 mmPb plate of The shielding rate of shielding of 0.5 mmPb plate 95.92%, 85.26 % based on the case of no shielding under each 60kVp, 100kVp tube voltage condition. When the shielding of Si-TiO{sub 2} pad was applied, the shielding rate equal to or greater than 0.5 mmPb plate was obtained at a thickness of 11 mm or more, and the shielding rate of 100% or more was confirmed at a thickness of 13 nn in 60kVp condition. When the shielding of Si-TiO{sub 2} pad was applied, the shielding rate equal to or greater than 0.5 mmPb plate was obtained at a thickness of 17 mm or more, and a shielding rate of 0.5 mmPb plate was observed at a thickness of 23 mm in 100kVp condition. Through the results of this study, We could confirm the possibility of manufacturing radiation protective materials that does not contain lead hazard using various metallic compound and liquid Si. This study shows that possibility of liquid Si and other metallic compound can harmonize easily. Beside, It is flexible and strong to physical stress than Pb obtained radiation protective clothes. But additional studies are needed to increase the shielding rate and reduce the weight.

  7. A Launch Requirements Trade Study for Active Space Radiation Shielding for Long Duration Human Missions

    Science.gov (United States)

    Singleterry, Robert C., Jr.; Bollweg, Ken; Martin, Trent; Westover, Shayne; Battiston, Roberto; Burger, William J.; Meinke, Rainer

    2015-01-01

    A trade study for an active shielding concept based on magnetic fields in a solenoid configuration versus mass based shielding was developed. Monte Carlo simulations were used to estimate the radiation exposure for two values of the magnetic field strength and the mass of the magnetic shield configuration. For each field strength, results were reported for the magnetic region shielding (end caps ignored) and total region shielding (end caps included but no magnetic field protection) configurations. A value of 15 cSv was chosen to be the maximum exposure for an astronaut. The radiation dose estimate over the total shield region configuration cannot be used at this time without a better understanding of the material and mass present in the end cap regions through a detailed vehicle design. The magnetic shield region configuration, assuming the end cap regions contribute zero exposure, can be launched on a single Space Launch System rocket and up to a two year mission can be supported. The magnetic shield region configuration results in two versus nine launches for a comparable mass based shielding configuration. The active shielding approach is clearly more mass efficient because of the reduced number of launches than the mass based shielding for long duration missions.

  8. Radiation Shielding Materials Containing Hydrogen, Boron, and Nitrogen: Systematic Computational and Experimental Study Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objectives of the proposed research are to develop a space radiation shielding material system that has high efficacy for shielding radiation and also has high...

  9. Study of gamma radiation shielding properties of ZnO− TeO2 glasses

    Indian Academy of Sciences (India)

    ray EBFs in the intermediate energy region. The reported new data on radiation shielding characteristics of zinctellurite glasses should be beneficial from the point of proper gamma shield designs when intended to be used as radiationshields.

  10. Comparative study of radiation shielding parameters for bismuth borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kaundal, Rajinder Singh, E-mail: rajinder_apd@yahoo.com [Department of Physics, School of Physical Sciences, Lovely Professional University, Phagwara, Punjab (India)

    2016-07-15

    Melt and quench technique was used for the preparation of glassy samples of the composition x Bi{sub 2}O{sub 3-}(1-x) B{sub 2}O{sub 3} where x= .05 to .040. XCOM computer program is used for the evaluation of gamma-ray shielding parameters of the prepared glass samples. Further the values of mass attenuation coefficients, effective atomic number and half value layer for the glassy samples have been calculated in the energy range from 1KeV to 100GeV. Rigidity of the glass samples have been analyzed by molar volume of the prepared glass samples. (author)

  11. Radiation Shielding Materials Containing Hydrogen, Boron, and Nitrogen: Systematic Computational and Experimental Study. Phase I

    Science.gov (United States)

    Thibeault, Sheila A.; Fay, Catharine C.; Lowther, Sharon E.; Earle, Kevin D.; Sauti, Godfrey; Kang, Jin Ho; Park, Cheol; McMullen, Amelia M.

    2012-01-01

    The key objectives of this study are to investigate, both computationally and experimentally, which forms, compositions, and layerings of hydrogen, boron, and nitrogen containing materials will offer the greatest shielding in the most structurally robust combination against galactic cosmic radiation (GCR), secondary neutrons, and solar energetic particles (SEP). The objectives and expected significance of this research are to develop a space radiation shielding materials system that has high efficacy for shielding radiation and that also has high strength for load bearing primary structures. Such a materials system does not yet exist. The boron nitride nanotube (BNNT) can theoretically be processed into structural BNNT and used for load bearing structures. Furthermore, the BNNT can be incorporated into high hydrogen polymers and the combination used as matrix reinforcement for structural composites. BNNT's molecular structure is attractive for hydrogen storage and hydrogenation. There are two methods or techniques for introducing hydrogen into BNNT: (1) hydrogen storage in BNNT, and (2) hydrogenation of BNNT (hydrogenated BNNT). In the hydrogen storage method, nanotubes are favored to store hydrogen over particles and sheets because they have much larger surface areas and higher hydrogen binding energy. The carbon nanotube (CNT) and BNNT have been studied as potentially outstanding hydrogen storage materials since 1997. Our study of hydrogen storage in BNNT - as a function of temperature, pressure, and hydrogen gas concentration - will be performed with a hydrogen storage chamber equipped with a hydrogen generator. The second method of introducing hydrogen into BNNT is hydrogenation of BNNT, where hydrogen is covalently bonded onto boron, nitrogen, or both. Hydrogenation of BN and BNNT has been studied theoretically. Hyper-hydrogenated BNNT has been theoretically predicted with hydrogen coverage up to 100% of the individual atoms. This is a higher hydrogen content

  12. Radiation shielding aspects for long manned mission to space: Criteria, survey study, and preliminary model

    Directory of Open Access Journals (Sweden)

    Sztejnberg Manuel

    2006-01-01

    Full Text Available The prospect of manned space missions outside Earth's orbit is limited by the travel time and shielding against cosmic radiation. The chemical rockets currently used in the space program have no hope of propelling a manned vehicle to a far away location such as Mars due to the enormous mass of fuel that would be required. The specific energy available from nuclear fuel is a factor of 106 higher than chemical fuel; it is therefore obvious that nuclear power production in space is a must. On the other hand, recent considerations to send a man to the Moon for a long stay would require a stable, secured and safe source of energy (there is hardly anything beyond nuclear power that would provide a useful and reliably safe sustainable supply of energy. National Aeronautics and Space Administration (NASA anticipates that the mass of a shielding material required for long travel to Mars is the next major design driver. In 2006 NASA identified a need to assess and evaluate potential gaps in existing knowledge and understanding of the level and types of radiation critical to astronauts' health during the long travel to Mars and to start a comprehensive study related to the shielding design of a spacecraft finding the conditions for the mitigation of radiation components contributing to the doses beyond accepted limits. In order to reduce the overall space craft mass, NASA is looking for the novel, multi-purpose and multi-functional materials that will provide effective shielding of the crew and electronics on board. The Laboratory for Neutronics and Geometry Computation in the School of Nuclear Engineering at Purdue University led by Prof. Tatjana Jevremović began in 2004 the analytical evaluations of different lightweight materials. The preliminary results of the design survey study are presented in this paper.

  13. Radiation shield for operator under radiation circumference

    Energy Technology Data Exchange (ETDEWEB)

    Nemezawa, Isao; Kimura, Tadahiro [Hitachi Ltd., Tokyo (Japan); Omori, Tetsu; Mizuochi, Akira

    1997-11-18

    A radiation shield for an upper half of a man`s body comprises a synthetic resin clothing, a rubber plate or a composite member of them formed into a bag. The bag is formed three dimensionally in the form of an open in front vest. A radiation shielding bag for the lower half of a man`s body is formed into three dimensionally in the form of open in front half trousers. A water injection port for injecting water as shielding liquid and a gas exhaust port are formed to each of the bags. Upon operation under radiation circumstance, the water injection ports and the gas exhaustion ports are opened, and shielding liquid is injected from the water injection ports to the bag so that the shielding liquid shields radiation rays. After closing the water injection ports and the gas exhaustion ports, an operator wears and buttons up the radiation shield of the upper half and the lower half to protect radiation exposure from the front, back and the side of a man. (I.N.)

  14. Measuring space radiation shielding effectiveness

    Science.gov (United States)

    Bahadori, Amir; Semones, Edward; Ewert, Michael; Broyan, James; Walker, Steven

    2017-09-01

    Passive radiation shielding is one strategy to mitigate the problem of space radiation exposure. While space vehicles are constructed largely of aluminum, polyethylene has been demonstrated to have superior shielding characteristics for both galactic cosmic rays and solar particle events due to the high hydrogen content. A method to calculate the shielding effectiveness of a material relative to reference material from Bragg peak measurements performed using energetic heavy charged particles is described. Using accelerated alpha particles at the National Aeronautics and Space Administration Space Radiation Laboratory at Brookhaven National Laboratory, the method is applied to sample tiles from the Heat Melt Compactor, which were created by melting material from a simulated astronaut waste stream, consisting of materials such as trash and unconsumed food. The shielding effectiveness calculated from measurements of the Heat Melt Compactor sample tiles is about 10% less than the shielding effectiveness of polyethylene. Shielding material produced from the astronaut waste stream in the form of Heat Melt Compactor tiles is therefore found to be an attractive solution for protection against space radiation.

  15. Measuring space radiation shielding effectiveness

    Directory of Open Access Journals (Sweden)

    Bahadori Amir

    2017-01-01

    Full Text Available Passive radiation shielding is one strategy to mitigate the problem of space radiation exposure. While space vehicles are constructed largely of aluminum, polyethylene has been demonstrated to have superior shielding characteristics for both galactic cosmic rays and solar particle events due to the high hydrogen content. A method to calculate the shielding effectiveness of a material relative to reference material from Bragg peak measurements performed using energetic heavy charged particles is described. Using accelerated alpha particles at the National Aeronautics and Space Administration Space Radiation Laboratory at Brookhaven National Laboratory, the method is applied to sample tiles from the Heat Melt Compactor, which were created by melting material from a simulated astronaut waste stream, consisting of materials such as trash and unconsumed food. The shielding effectiveness calculated from measurements of the Heat Melt Compactor sample tiles is about 10% less than the shielding effectiveness of polyethylene. Shielding material produced from the astronaut waste stream in the form of Heat Melt Compactor tiles is therefore found to be an attractive solution for protection against space radiation.

  16. Study of gamma radiation shielding properties of ZnO−TeO2 glasses

    Indian Academy of Sciences (India)

    2017-07-25

    Jul 25, 2017 ... tellurite glasses should be beneficial from the point of proper gamma shield designs when intended to be used as radiation shields. Keywords. Mass attenuation coefficient; effective atomic number; electron density; exposure buildup factors; tellurite glass. 1. Introduction. High-energy gamma rays are a type ...

  17. Exploring innovative radiation shielding approaches in space: A material and design study for a wearable radiation protection spacesuit

    Science.gov (United States)

    Vuolo, M.; Baiocco, G.; Barbieri, S.; Bocchini, L.; Giraudo, M.; Gheysens, T.; Lobascio, C.; Ottolenghi, A.

    2017-11-01

    We present a design study for a wearable radiation-shielding spacesuit, designed to protect astronauts' most radiosensitive organs. The suit could be used in an emergency, to perform necessary interventions outside a radiation shelter in the space habitat in case of a Solar Proton Event (SPE). A wearable shielding system of the kind we propose has the potential to prevent the onset of acute radiation effects in this scenario. In this work, selection of materials for the spacesuit elements is performed based on the results of dedicated GRAS/Geant4 1-dimensional Monte Carlo simulations, and after a trade-off analysis between shielding performance and availability of resources in the space habitat. Water is the first choice material, but also organic compounds compatible with a human space habitat are considered (such as fatty acids, gels and liquid organic wastes). Different designs and material combinations are proposed for the spacesuits. To quantify shielding performance we use GRAS/Geant4 simulations of an anthropomorphic phantom in an average SPE environment, with and without the spacesuit, and we compare results for the dose to Blood Forming Organs (BFO) in Gy-Eq, i.e. physical absorbed dose multiplied by the proton Relative Biological Effectiveness (RBE) for non-cancer effects. In case of SPE occurrence for Intra-Vehicular Activities (IVA) outside a radiation shelter, dose reductions to BFO in the range of 44-57% are demonstrated to be achievable with the spacesuit designs made only of water elements, or of multi-layer protection elements (with a thin layer of a high density material covering the water filled volume). Suit elements have a thickness in the range 2-6 cm and the total mass for the garment sums up to 35-43 kg depending on model and material combination. Dose reduction is converted into time gain, i.e. the increase of time interval between the occurrence of a SPE and the moment the dose limit to the BFO for acute effects is reached. Wearing a

  18. Summary of Prometheus Radiation Shielding Nuclear Design Analysis

    Energy Technology Data Exchange (ETDEWEB)

    J. Stephens

    2006-01-13

    This report transmits a summary of radiation shielding nuclear design studies performed to support the Prometheus project. Together, the enclosures and references associated with this document describe NRPCT (KAPL & Bettis) shielding nuclear design analyses done for the project.

  19. Novel Concepts for Radiation Shielding Materials

    Science.gov (United States)

    Oliva-Buisson, Yvette J.

    2014-01-01

    It is critical that safety factors be maximized with respect to long duration, extraterrestrial space flight. Any significant improvement in radiation protection will be critical in ensuring the safety of crew and hardware on such missions. The project goal is to study novel concepts for radiation shielding materials that can be used for long-duration space missions. As part of this project we will investigate the use of thin films for the evaluation of a containment system that can retain liquid hydrogen and provide the necessary hydrogen density for effective shielding.

  20. The Study on the Conductivity Performance and Shielding Effectiveness of Electro-magnetic Radiation of Polyethylene Film with Different Content of Carbon Black Particles

    Institute of Scientific and Technical Information of China (English)

    SUN Run-jun; LAI Kan; ZHANG Jian-chun; HUO Yan

    2004-01-01

    With the help of the testing apparatus made by ourselves for shielding electromagnetic radiation, the electric conductivity and shielding effectiveness of electromagnetic radiation of polyethylene film contained different content of carbon particles was systematically studied in this paper. The results indicate that the electric conductivity and shielding effectiveness of electromagnetic radiation of polyethylene /carbon film have closely relations with content of carbon black particles, which exists a critical content value as 14%~30% and its properties will have a tremendous change.

  1. 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.

  2. Radiation Shielding Materials and Containers Incorporating Same

    Energy Technology Data Exchange (ETDEWEB)

    Mirsky, Steven M.; Krill, Stephen J.; and Murray, Alexander P.

    2005-11-01

    An improved radiation shielding material and storage systems for radioactive materials incorporating the same. The PYRolytic Uranium Compound (''PYRUC'') shielding material is preferably formed by heat and/or pressure treatment of a precursor material comprising microspheres of a uranium compound, such as uranium dioxide or uranium carbide, and a suitable binder. The PYRUC shielding material provides improved radiation shielding, thermal characteristic, cost and ease of use in comparison with other shielding materials. The shielding material can be used to form containment systems, container vessels, shielding structures, and containment storage areas, all of which can be used to house radioactive waste. The preferred shielding system is in the form of a container for storage, transportation, and disposal of radioactive waste. In addition, improved methods for preparing uranium dioxide and uranium carbide microspheres for use in the radiation shielding materials are also provided.

  3. A Novel Radiation Shielding Material Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation shielding simulations showed that epoxy loaded with 10-70% polyethylene would be an excellent shielding material against GCRs and SEPs. Milling produced an...

  4. Radiation Shielding Systems Using Nanotechnology

    Science.gov (United States)

    Chen, Bin (Inventor); McKay, Christoper P. (Inventor)

    2011-01-01

    A system for shielding personnel and/or equipment from radiation particles. In one embodiment, a first substrate is connected to a first array or perpendicularly oriented metal-like fingers, and a second, electrically conducting substrate has an array of carbon nanostructure (CNS) fingers, coated with an electro-active polymer extending toward, but spaced apart from, the first substrate fingers. An electric current and electric charge discharge and dissipation system, connected to the second substrate, receives a current and/or voltage pulse initially generated when the first substrate receives incident radiation. In another embodiment, an array of CNSs is immersed in a first layer of hydrogen-rich polymers and in a second layer of metal-like material. In another embodiment, a one- or two-dimensional assembly of fibers containing CNSs embedded in a metal-like matrix serves as a radiation-protective fabric or body covering.

  5. Radiation shielding concrete made of Basalt aggregates.

    Science.gov (United States)

    Alhajali, S; Yousef, S; Kanbour, M; Naoum, B

    2013-04-01

    In spite of the fact that Basalt is a widespread type of rock, there is very little available information on using it as aggregates for concrete radiation shielding. This paper investigates the possibility of using Basalt for the aforementioned purpose. The results have shown that Basalt could be used successfully for preparing radiation shielding concrete, but some attention should be paid to the choice of the suitable types of Basalt and for the neutron activation problem that could arise in the concrete shield.

  6. Thermal radiation shielding by nanoporous membranes based on anodic alumina

    Science.gov (United States)

    Muratova, E. N.; Matyushkin, L. B.; Moshnikov, V. A.; Chernyakova, K. V.; Vrublevsky, I. A.

    2017-07-01

    The paper is devoted to infrared thermography studies of nanoporous alumina membranes with various geometric parameters of the porous layer: its thickness and average pore diameter. Thermal radiation shielding by anodic alumina membranes is presented. The result obtained showed that nanoporous alumina membranes can be used as heat shields to smooth contrast of thermal radiation of the object and the surrounding background.

  7. Radiation shielding for future space exploration missions

    Science.gov (United States)

    DeWitt, Joel Michael

    Scope and Method of Study. The risk to space crew health and safety posed by exposure to space radiation is regarded as a significant obstacle to future human space exploration. To countermand this risk, engineers and designers in today's aerospace community will require detailed knowledge of a broad range of possible materials suitable for the construction of future spacecraft or planetary surface habitats that provide adequate protection from a harmful space radiation environment. This knowledge base can be supplied by developing an experimental method that provides quantitative information about a candidate material's space radiation shielding efficacy with the understanding that (1) shielding is currently the only practical countermeasure to mitigate the effects of space radiation on human interplanetary missions, (2) any mass of a spacecraft or planetary surface habitat necessarily alters the incident flux of ionizing radiation on it, and (3) the delivery of mass into LEO and beyond is expensive and therefore may benefit from the possible use of novel multifunctional materials that could in principle reduce cost as well as ionizing radiation exposure. The developed method has an experimental component using CR-39 PNTD and Al2O3:C OSLD that exposes candidate space radiation shielding materials of varying composition and depth to a representative sample of the GCR spectrum that includes 1 GeV 1H and 1 GeV/n 16O, 28Si, and 56Fe heavy ion beams at the BNL NSRL. The computer modeling component of the method used the Monte Carlo radiation transport code FLUKA to account for secondary neutrons that were not easily measured in the laboratory. Findings and Conclusions. This study developed a method that quantifies the efficacy of a candidate space radiation shielding material relative to the standard of polyethylene using a combination of experimental and computer modeling techniques. The study used established radiation dosimetry techniques to present an empirical

  8. Improved Metal-Polymeric Laminate Radiation Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposed Phase I program, a multifunctional lightweight radiation shield composite will be developed and fabricated. This structural radiation shielding will...

  9. Foam-Reinforced Polymer Matrix Composite Radiation Shields Project

    Data.gov (United States)

    National Aeronautics and Space Administration — New and innovative lightweight radiation shielding materials are needed to protect humans in future manned exploration vehicles. Radiation shielding materials are...

  10. A Study on the Radiation Source Effect to the Radiation Shielding Analysis for a Spent-Fuel Cask Design with Burnup-Credit

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Soon Young; Kim, Kyung O [RADCORE Co., Ltd., Daejeon (Korea, Republic of); Ko, Jae Hoon; Lee, Gang Gu [Korea Nuclear Engineering and Service Corp., Daejeon (Korea, Republic of); Kim, Tae Man; Yoon, Jeong Hyun [Korea Raioactive waste Management Corp., Daejeon (Korea, Republic of)

    2011-06-15

    The radiation shielding analysis for a Burnup-credit (BUC) cask designed under the management of Korea Radioactive Waste Management Corporation (KRMC) was performed to examine the contribution of each radiation source affecting dose rate distribution around the cask. Various radiation sources, which contain neutron and gamma-ray sources placed in active fuel region and the activation source, and imaginary nuclear fuel were all considered in the MCNP calculation model to realistically simulate the actual situations. It was found that the maximum external and surface dose rates of the spent fuel cask were satisfied with the domestic standards both in normal and accident conditions. In normal condition, the radiation dose rate distribution around the cask was mainly influenced by activation source (60 Co radioisotope); in another case, the neutron emitted in active fuel region contributed about 90% to external dose rate at 1m distance from side surface of the cask. Besides, the contribution level of activation source was dramatically increased to the dose rates in top and bottom regions of the cask. From this study, it was recognized that the detailed investigation on the radiation sources should be performed conservatively and accurately in the process of radiation shielding analysis for a BUC cask.

  11. Nanocomposite for Radiation Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's Advanced Extravehicular Activity (EVA) program requires the need for materials that can protect astronauts and spacecrafts from ionizing radiations such as...

  12. Magnet Architectures and Active Radiation Shielding Study - SR2S Workshop

    Science.gov (United States)

    Westover, Shane; Meinke, Rainer; Burger, William; Ilin, Andrew; Nerolich, Shaun; Washburn, Scott

    2014-01-01

    Analyze new coil configurations with maturing superconductor technology -Develop vehicle-level concept solutions and identify engineering challenges and risks -Shielding performance analysis Recent advances in superconducting magnet technology and manufacturing have opened the door for re-evaluating active shielding solutions as an alternative to mass prohibitive passive shielding.Publications on static magnetic field environments and its bio-effects were reviewed. Short-term exposure information is available suggesting long term exposure may be okay. Further research likely needed. center dotMagnetic field safety requirements exist for controlled work environments. The following effects have been noted with little noted adverse effects -Magnetohydrodynamic (MHD) effects on ionized fluids (e.g. blood) creating an aortic voltage change -MHD interaction elevates blood pressure (BP) center dot5 Tesla equates to 5% BP elevation -Prosthetic devises and pacemakers are an issue (access limit of 5 gauss).

  13. Space Radiation Shielding Studies for Astronaut and Electronic Component Risk Assessment

    Science.gov (United States)

    Fuchs, Jordan Robert

    2010-01-01

    The dosimetry component of the Center for Radiation Engineering and Science for Space Exploration (CRESSE) will design, develop and characterize the response of a suite of radiation detectors and supporting instrumentation and electronics with three primary goals that will: (1) Use established space radiation detection systems to characterize the primary and secondary radiation fields existing in the experimental test-bed zones during exposures at particle accelerator facilities. (2) Characterize the responses of newly developed space radiation detection systems in the experimental test-bed zones during exposures at particle accelerator facilities, and (3) Provide CRESSE collaborators with detailed dosimetry information in experimental test-bed zones.

  14. Dark current and radiation shielding studies for the ILC main linac

    Energy Technology Data Exchange (ETDEWEB)

    Mokhov, Nikolai V. [Fermilab; Rakhno, I. L. [Fermilab; Solyak, N. A. [Fermilab; Sukhanov, A. [Fermilab; Tropin, I. S. [Fermilab

    2016-12-05

    Electrons of dark current (DC), generated in high-gradient superconducting RF cavities (SRF) due to field emission, can be accelerated up to very high energies—19 GeV in the case of the International Linear Collider (ILC) main linac—before they are removed by focusing and steering magnets. Electromagnetic and hadron showers generated by such electrons can represent a significant radiation threat to the linac equipment and personnel. In our study, an operational scenario is analysed which is believed can be considered as the worst case scenario for the main linac regarding the DC contribution to the radiation environment in the main linac tunnel. A detailed modelling is performed for the DC electrons which are emitted from the surface of the SRF cavities and can be repeatedly accelerated in the high-gradient fields in many SRF cavities. Results of MARS15 Monte Carlo calculations, performed for the current main linac tunnel design, reveal that the prompt dose design level of 25 μSv/hr in the service tunnel can be provided by a 2.3-m thick concrete wall between the main and service ls.

  15. Using FLUKA to Study Concrete Square Shield Performance in Attenuation of Neutron Radiation Produced by APF Plasma Focus Neutron Source

    Science.gov (United States)

    Nemati, M. J.; Habibi, M.; Amrollahi, R.

    2013-04-01

    In 2010, representatives from the Nuclear Engineering and physics Department of Amirkabir University of Technology (AUT) requested development of a project with the objective of determining the performance of a concrete shield for their Plasma Focus as neutron source. The project team in Laboratory of Nuclear Engineering and physics department of Amirkabir University of Technology choose some shape of shield to study on their performance with Monte Carlo code. In the present work, the capability of Monte Carlo code FLUKA will be explored to model the APF Plasma Focus, and investigating the neutron fluence on the square concrete shield in each region of problem. The physical models embedded in FLUKA are mentioned, as well as examples of benchmarking against future experimental data. As a result of this study suitable thickness of concrete for shielding APF will be considered.

  16. Boron filled siloxane polymers for radiation shielding

    Science.gov (United States)

    Labouriau, Andrea; Robison, Tom; Shonrock, Clinton; Simmonds, Steve; Cox, Brad; Pacheco, Adam; Cady, Carl

    2018-03-01

    The purpose of the present work was to evaluate changes to structure-property relationships of 10B filled siloxane-based polymers when exposed to nuclear reactor radiation. Highly filled polysiloxanes were synthesized with the intent of fabricating materials that could shield high neutron fluences. The newly formulated materials consisted of cross-linked poly-diphenyl-methylsiloxane filled with natural boron and carbon nanofibers. This polymer was chosen because of its good thermal and chemical stabilities, as well as resistance to ionizing radiation thanks to the presence of aromatic groups in the siloxane backbone. Highly isotopically enriched 10B filler was used to provide an efficient neutron radiation shield, and carbon nanofibers were added to improve mechanical strength. This novel polymeric material was exposed in the Annular Core Research Reactor (ACRR) at Sandia National Labs to five different neutron/gamma fluxes consisting of very high neutron fluences within very short time periods. Thermocouples placed on the specimens recorded in-situ temperature changes during radiation exposure, which agreed well with those obtained from our MCNP simulations. Changes in the microstructural, thermal, chemical, and mechanical properties were evaluated by SEM, DSC, TGA, FT-IR NMR, solvent swelling, and uniaxial compressive load measurements. Our results demonstrate that these newly formulated materials are well-suitable to be used in applications that require exposure to different types of ionizing conditions that take place simultaneously.

  17. Radiation shielding analyses for JT-60SU

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Y. [Mitsubishi Heavy Industries Ltd., Tokyo (Japan); Neyatani, Y. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Ishida, S.; Ashida, S.; Sawamura, H.; Tominaga, M.; Nishimura, K. [Computer Software Development Co., Ltd., Shinjuku, Tokyo (Japan)

    2000-03-01

    Radiation shielding analyses were done for JT-60 Super Upgrade (JT-60SU) of JAERI in Japan, and are reported here. From a viewpoint of the operation and the maintenance, it is important how accurately to evaluate the nuclear heating rate in the superconducting magnet and the activation of components around the vacuum vessel by irradiation of fusion neutrons. A boot-strapped calculation step was applied to the analyses to reduce the redundancy of the conservative in the results. The nuclear heating rate in the superconducting magnets and the maximum {gamma}-ray dose rate one month after shutdown in the cryostat were within the design limits of 2 mW/cc and 10 {mu}Sv/hr, respectively, in the nuclear shielding for a D-D neutron production rate of 1x10{sup 18} s{sup -1}. (author)

  18. Approximate design calculation methods for radiation streaming in shield irregularities

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Toshimasa; Hirao, Yoshihiro [Ship Research Inst., Mitaka, Tokyo (Japan); Yoritsune, Tsutomu

    1997-10-01

    Investigation and assessment are made for approximate design calculation methods of radiation streaming in shield irregularities. Investigation is made for (1) source, (2) definition of streaming radiation components, (3) calculation methods of streaming radiation, (4) streaming formulas for each irregularity, (5) difficulties in application of streaming formulas, etc. Furthermore, investigation is made for simple calculation codes and albedo data. As a result, it is clarified that streaming calculation formulas are not enough to cover various irregularities and their accuracy or application limit is not sufficiently clear. Accurate treatment is not made in the formulas with respect to the radiation behavior for slant incidence, bend part, offset etc., that results in too much safety factors in the design calculation and distrust of the streaming calculation. To overcome the state and improve the accuracy of the design calculation for shield irregularities, it is emphasized to assess existing formulas and develop better formulas based on systematic experimental studies. (author)

  19. Early test facilities and analytic methods for radiation shielding: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ingersoll, D T [comp.; Oak Ridge National Lab., TN (United States); Ingersoll, J K [comp.; Tec-Com, Knoxville, TN (United States)

    1992-11-01

    This report represents a compilation of eight papers presented at the 1992 American Nuclear Society/European Nuclear Society International Meeting. The meeting is of special significance since it commemorates the fiftieth anniversary of the first controlled nuclear chain reaction. The papers contained in this report were presented in a special session organized by the Radiation Protection and Shielding Division in keeping with the historical theme of the meeting. The paper titles are good indicators of their content and are: (1) The origin of radiation shielding research: The Oak Ridge experience, (2) Shielding research at the hanford site, (3) Aircraft shielding experiments at General Dynamics Fort Worth, 1950-1962, (4) Where have the neutrons gone , a history of the tower shielding facility, (5) History and evolution of buildup factors, (6) Early shielding research at Bettis atomic power laboratory, (7) UK reactor shielding: then and now, (8) A very personal view of the development of radiation shielding theory.

  20. Polyolefin-Nanocrystal Composites for Radiation Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — EIC Laboratories Inc. is proposing a lightweight multifunctional polymer/nanoparticle composite for radiation shielding during long-duration lunar missions. Isolated...

  1. ITER radiation shielding and neutronics analysis

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, R.T.; Iida, H.; Khripunov, V. [ITER, Garching (Germany). Joint Work Site; Sawan, M. [Fusion Technology Institute, University of Wisconsin, Madison, WI 53706 (United States); Inoue, T. [Japan Atomic Energy Research Institute, Tokai-Mura, Ibaraki-ken (Japan)

    1998-09-01

    Two dimensional radiation transport calculations have been carried out to determine radiation streaming through the ITER equatorial ports. The NBI port has been identified as the most critical. Shielding requirements were estimated to minimize the nuclear heating rates in the toroidal field (TF) coils and the activation of the cryostat, where hands-on maintenance is anticipated. The shielding efficiency of steel/water port walls was investigated as a function of port and wall dimensions and steel volume fraction. For open ports, i.e. the neutral beam injector ducts, 40-50 cm thick port walls composed of 40% SS-60% H{sub 2}O-75% SS-25% H{sub 2}O will reduce the TF coil heating to acceptable levels, while 60-65 cm thick walls are necessary for reducing the dose rates at {proportional_to}2 weeks after shutdown to levels of 750 {mu}Sv h{sup -1} at the cryostat. (orig.) 10 refs.

  2. Tissue Equivalent Proportional Counter Microdosimetry Measurements Utilized Aboard Aircraft and in Accelerator Based Space Radiation Shielding Studies

    Science.gov (United States)

    Gersey, Brad B.; Wilkins, Richard T.

    2010-01-01

    This slide presentation reviews the Tissue Equivalent Proportional Counter (TEPC), a description of the spatially restricted LET Model, high energy proton TEPC and the results of modeling, the study of shielding and the results from the flight exposures with the TEPC.

  3. Investigation of Radiation Protection Methodologies for Radiation Therapy Shielding Using Monte Carlo Simulation and Measurement

    Science.gov (United States)

    Tanny, Sean

    The advent of high-energy linear accelerators for dedicated medical use in the 1950's by Henry Kaplan and the Stanford University physics department began a revolution in radiation oncology. Today, linear accelerators are the standard of care for modern radiation therapy and can generate high-energy beams that can produce tens of Gy per minute at isocenter. This creates a need for a large amount of shielding material to properly protect members of the public and hospital staff. Standardized vault designs and guidance on shielding properties of various materials are provided by the National Council on Radiation Protection (NCRP) Report 151. However, physicists are seeking ways to minimize the footprint and volume of shielding material needed which leads to the use of non-standard vault configurations and less-studied materials, such as high-density concrete. The University of Toledo Dana Cancer Center has utilized both of these methods to minimize the cost and spatial footprint of the requisite radiation shielding. To ensure a safe work environment, computer simulations were performed to verify the attenuation properties and shielding workloads produced by a variety of situations where standard recommendations and guidance documents were insufficient. This project studies two areas of concern that are not addressed by NCRP 151, the radiation shielding workload for the vault door with a non-standard design, and the attenuation properties of high-density concrete for both photon and neutron radiation. Simulations have been performed using a Monte-Carlo code produced by the Los Alamos National Lab (LANL), Monte Carlo Neutrons, Photons 5 (MCNP5). Measurements have been performed using a shielding test port designed into the maze of the Varian Edge treatment vault.

  4. Study on reducing radiation dose in dental radiography for children, 2. Problems of the ready-made cervical shield's thyroid gland radiation protection for the pedodontic intraoral radiography

    Energy Technology Data Exchange (ETDEWEB)

    Shikone, Mitsuru; Tsuchida, Atsushi; Tateno, Hidemi; Uchimura, Noboru; Higaki, Morio; Kanno, Masanori; Higashi, Tomomitsu

    1987-03-01

    Although it is well understood that diagnostic dental radiographic examination is an indispensible procedure of the dental examination, it always carries the danger of radiation harm especially to the pedodontic patients who are more radiosensitive than the adult group. At the time of exposure, in specific, certain undeveloped tissues such as the thyroid (reverting postmitotic cells), the optic lens, and the reproductive cells (gonads) must be shielded from any unnecessary radiation. In this study, using the pedodontic intraoral radiographic examination method, four various cervical shields of four separate manufacturers were investigated. With the aid of the Thermo Luminescent Dosimeter (TLD), the specific exposure doses to the thyroid gland region were analyzed. At the same time, individual cervical shield's adaptation to the neck was examined. The results were as follows: (1) Even with the use of the cervical shield, maximum dose of 98.64 +- 11.13 mR (lower molar periapical radiography method), and minimum of 34.27 +- 6.69 mR (lower anterior periapical radiography method) were obtained at the thyroid gland region. (2) It was discovered that poor adaptation of the cervical shield to the neck and also poor adaptation of the long cones (position indicating devices, PID) occured upon patient opening his/her mouth.

  5. Physical analysis of the radiation shielding for the medical accelerators

    Science.gov (United States)

    Li, Q. F.; Xing, Q. Z.; Kong, C. C.

    2009-02-01

    Radiation safety standards today require comprehensive shielding protection schemes for all particle accelerators. The original shielding system of BJ-20 (BeiJing-20 MeV), the high-energy medical electron linac, was designed only for the 18 MeV level. And the dose caused by the lost electrons in the 270° bending magnet system was neglected. In this paper, the leakage dose of BJ-20 is carefully analyzed. The radiation leakage dose distribution of the photons coming from the accelerator head is obtained for energy levels of 6, 12, 14, and 18 MeV. The dose of the photoneutrons is especially analyzed for the 18 MeV level. The result gives that even neglecting the dose from the 270° bending magnet system, the shielding system is still not enough for the energy levels lower than 18 MeV. The radiation leakage produced by electrons that are lost in the 270° bending magnet system has been particularly studied. Using beam transport theory and Monte Carlo sampling methods, which have been combined in calculations, we have obtained the distribution of the energy, position, and direction of the lost electrons. These data were then further processed by the Monte Carlo N-particle (MCNP) code as input data. The results show that when the electron loss rate in the 270° bending magnet system is 13.5%, the radiation leakage dose of the photons generated by the lost electrons is 0.1% higher than that at the isocenter, and the corresponding relative leakage dose of the photoneutrons reaches 0.045% around an angle of 170° at 18 MeV level. Both of these parameters exceed radioprotection safety standards for medical accelerators. The original shielding design is therefore not suitable and is also incomplete since the radiation produced by the electrons being lost in the 270° bending magnet system was neglected and the leakage dose for the low-energy levels was not considered in the original design. Our calculations provide a very useful tool for further optimization and design

  6. Enhanced radiation shielding with galena concrete

    Directory of Open Access Journals (Sweden)

    Hadad Kamal

    2015-01-01

    Full Text Available A new concrete, containing galena mineral, with enhanced shielding properties for gamma sources is developed. To achieve optimized shielding properties, ten types of galena concrete containing different mixing ratios and a reference normal concrete of 2300 kg/m3 density are studied experimentally and numerically using Monte Carlo and XCOM codes. For building galena concrete, in addition to the main composition, micro-silica and water, galena mineral (containing lead were used. The built samples have high density of 4470 kg/m3 to 5623 kg/m3 and compressive strength of 628 kg/m2 to 685 kg/m2. The half and tenth value layers (half value layer and tenth value layers for the galena concrete, when irradiated with 137Cs gamma source, were found to be 1.45 cm and 4.94 cm, respectively. When irradiated with 60Co gamma source, half value layer was measured to be 2.42 cm. The computation modeling by FLUKA and XCOM shows a good agreement between experimental and computational results.

  7. Effects of various radiation source characteristics on shielding requirements at the potential Yucca Mountain repository

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.W.; Miller, D.D. [Bechtel National, Inc., San Francisco, CA (United States); Hill, R.R. [Sandia National Labs., Albuquerque, NM (United States)

    1992-02-01

    This radiation shielding study provides dose rate information that can be used to estimate required shielding thicknesses for different repository configurations, including various hot cells and vaults in the waste-handling building, the boreholes in the underground emplacement area, and the transfer casks. The study determines gamma and neutron source strengths for various waste types and source geometries representative of conditions at the repository and determines dose rates as a function of shielding thickness for selected materials.

  8. Radiation protection, radiation safety and radiation shielding assessment of HIE-ISOLDE.

    Science.gov (United States)

    Romanets, Y; Bernardes, A P; Dorsival, A; Gonçalves, I F; Kadi, Y; di Maria, S; Vaz, P; Vlachoudis, V; Vollaire, J

    2013-07-01

    The high intensity and energy ISOLDE (HIE-ISOLDE) project is an upgrade to the existing ISOLDE facility at CERN. The foreseen increase in the nominal intensity and the energy of the primary proton beam of the existing ISOLDE facility aims at increasing the intensity of the produced radioactive ion beams (RIBs). The currently existing ISOLDE facility uses the proton beam from the proton-synchrotron booster with an energy of 1.4 GeV and an intensity up to 2 μA. After upgrade (final stage), the HIE-ISOLDE facility is supposed to run at an energy up to 2 GeV and an intensity up to 4 μA. The foreseen upgrade imposes constrains, from the radiation protection and the radiation safety point of view, to the existing experimental and supply areas. Taking into account the upgraded energy and intensity of the primary proton beam, a new assessment of the radiation protection and radiation safety of the HIE-ISOLDE facility is necessary. Special attention must be devoted to the shielding assessment of the beam dumps and of the experimental areas. In this work the state-of-the-art Monte Carlo particle transport simulation program FLUKA was used to perform the computation of the ambient dose equivalent rate distribution and of the particle fluxes in the projected HIE-ISOLDE facility (taking into account the upgrade nominal primary proton beam energy and intensity) and the shielding assessment of the facility, with the aim of identifying in the existing facility (ISOLDE) the critical areas and locations where new or reinforced shielding may be necessary. The consequences of the upgraded proton beam parameters on the operational radiation protection of the facility were studied.

  9. Application of Advanced Radiation Shielding Materials to Inflatable Structures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This innovation is a weight-optimized, inflatable structure that incorporates radiation shielding materials into its construction, for use as a habitation module or...

  10. Radiation Shielding and Hydrogen Storage with Multifunctional Carbon Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project addresses two vital problems for long-term space travel activities: radiation shielding and hydrogen storage for power and propulsion. While both...

  11. Improved Metal-Polymeric Laminate Radiation Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposed Phase II program, builds on the phase I feaibility where a multifunctional lightweight radiation shield composite was developed and fabricated. This...

  12. Characterizing and Manufacturing Multifunctional Radiation Shielding Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project addresses two vital problems for long-term space travel activities: radiation shielding and hydrogen storage for power and propulsion. While both...

  13. Multifunctional, Boron-Foam Based Radiation Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA vision of Space Exploration requires new approaches to radiation shielding. Both Spiral 2 and Spiral 3 concepts are extremely sensitive to weight reduction....

  14. Multifunctional B/C Fiber Composites for Radiation Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation shielding is an enabling technology required for extended manned missions to the Moon, Mars and the planets beyond. Multifunctional structural must protect...

  15. Radiation shielding of high-energy neutrons in SAD

    Energy Technology Data Exchange (ETDEWEB)

    Seltborg, P. [Department of Nuclear and Reactor Physics, Albanova University Centre, Royal Institute of Technology, S-106 91 Stockholm (Sweden)]. E-mail: per@neutron.kth.se; Polanski, A. [Joint Institute for Nuclear Research, 141 980, Joliot-Curie 6, Dubna (Russian Federation); Petrochenkov, S. [Joint Institute for Nuclear Research, 141 980, Joliot-Curie 6, Dubna (Russian Federation); Lopatkin, A. [Research and Development Institute of Power Engineering, 101 000, PB78, Moscow (Russian Federation); Gudowski, W. [Department of Nuclear and Reactor Physics, Albanova University Centre, Royal Institute of Technology, S-106 91 Stockholm (Sweden); Shvetsov, V. [Joint Institute for Nuclear Research, 141 980, Joliot-Curie 6, Dubna (Russian Federation)

    2005-09-11

    The radiation fields and the effective dose at the Sub-critical Assembly in Dubna (SAD) have been studied with the Monte Carlo code MCNPX. The effective dose above the shielding, i.e. in the direction of the incident proton beam of 3.0 {mu}A, was found to be about 190 {mu}Sv h{sup -1}. This value meets the dose limits according to Russian radiation protection regulations, provided that access to the rooms in this area is not allowed for working personnel during operation. By separating the radiation fields into a spallation- and a fission-induced part, it was shown that the neutrons with energy higher than 10 MeV, originating exclusively from the proton-induced spallation reactions in the target, contribute for the entire part of the radiation fields and the effective dose at the top of the shielding. Consequently, the effective dose above the SAD reactor system is merely dependent on the proton beam properties and not on the reactivity of the core.

  16. Analysis of low-dose radiation shield effectiveness of multi-gate polymeric sheets

    Science.gov (United States)

    Kim, S. C.; Lee, H. K.; Cho, J. H.

    2014-07-01

    Computed tomography (CT) uses a high dose of radiation to create images of the body. As patients are exposed to radiation during a CT scan, the use of shielding materials becomes essential in CT scanning. This study was focused on the radiation shielding materials used for patients during a CT scan. In this study, sheets were manufactured to shield the eyes and the thyroid, the most sensitive parts of the body, against radiation exposure during a CT scan. These sheets are manufactured using silicone polymers, barium sulfate (BaSO4) and tungsten, with the aim of making these sheets equally or more effective in radiation shielding and more cost-effective than lead sheets. The use of barium sulfate drew more attention than tungsten due to its higher cost-effectiveness. The barium sulfate sheets were coated to form a multigate structure by applying the maximum charge rate during the agitator and subsequent mixing processes and creating multilayered structures on the surface. To measure radiation shielding effectiveness, the radiation dose was measured around both eyes and the thyroid gland using sheets in three different thicknesses (1, 2 and 3 mm). Among the 1 and 2 mm sheets, the Pb sheets exhibited greater effectiveness in radiation shielding around both eyes, but the W sheets were more effective in radiation shielding around the thyroid gland. In the 3 mm sheets, the Pb sheet also attenuated a higher amount of radiation around both eyes while the W sheet was more effective around the thyroid gland. In conclusion, the sheets made from barium sulfate and tungsten proved highly effective in shielding against low-dose radiation in CT scans without causing ill-health effects, unlike lead.

  17. Validity of the Aluminum Equivalent Approximation in Space Radiation Shielding

    Science.gov (United States)

    Badavi, Francis F.; Adams, Daniel O.; Wilson, John W.

    2009-01-01

    The origin of the aluminum equivalent shield approximation in space radiation analysis can be traced back to its roots in the early years of the NASA space programs (Mercury, Gemini and Apollo) wherein the primary radiobiological concern was the intense sources of ionizing radiation causing short term effects which was thought to jeopardize the safety of the crew and hence the mission. Herein, it is shown that the aluminum equivalent shield approximation, although reasonably well suited for that time period and to the application for which it was developed, is of questionable usefulness to the radiobiological concerns of routine space operations of the 21 st century which will include long stays onboard the International Space Station (ISS) and perhaps the moon. This is especially true for a risk based protection system, as appears imminent for deep space exploration where the long-term effects of Galactic Cosmic Ray (GCR) exposure is of primary concern. The present analysis demonstrates that sufficiently large errors in the interior particle environment of a spacecraft result from the use of the aluminum equivalent approximation, and such approximations should be avoided in future astronaut risk estimates. In this study, the aluminum equivalent approximation is evaluated as a means for estimating the particle environment within a spacecraft structure induced by the GCR radiation field. For comparison, the two extremes of the GCR environment, the 1977 solar minimum and the 2001 solar maximum, are considered. These environments are coupled to the Langley Research Center (LaRC) deterministic ionized particle transport code High charge (Z) and Energy TRaNsport (HZETRN), which propagates the GCR spectra for elements with charges (Z) in the range I aluminum equivalent approximation for a good polymeric shield material such as genetic polyethylene (PE). The shield thickness is represented by a 25 g/cm spherical shell. Although one could imagine the progression to greater

  18. Thick Galactic Cosmic Radiation Shielding Using Atmospheric Data

    Science.gov (United States)

    Youngquist, Robert C.; Nurge, Mark A.; Starr, Stanley O.; Koontz, Steven L.

    2013-01-01

    NASA is concerned with protecting astronauts from the effects of galactic cosmic radiation and has expended substantial effort in the development of computer models to predict the shielding obtained from various materials. However, these models were only developed for shields up to about 120 g!cm2 in thickness and have predicted that shields of this thickness are insufficient to provide adequate protection for extended deep space flights. Consequently, effort is underway to extend the range of these models to thicker shields and experimental data is required to help confirm the resulting code. In this paper empirically obtained effective dose measurements from aircraft flights in the atmosphere are used to obtain the radiation shielding function of the earth's atmosphere, a very thick shield. Obtaining this result required solving an inverse problem and the method for solving it is presented. The results are shown to be in agreement with current code in the ranges where they overlap. These results are then checked and used to predict the radiation dosage under thick shields such as planetary regolith and the atmosphere of Venus.

  19. A Reinforcement for Multifunctional Composites for Non-Parasitic Radiation Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Innovative lightweight radiation shielding materials are enabling to shield humans in aerospace transportation vehicles and other human habited spaces....

  20. RADIATION SHIELDING PROPERTIES OF HEAVY AGGREGATES

    OpenAIRE

    AKKURT, Iskender; KILIÇARSLAN, Şemsettin; BASYIGIT, Celalettin; günoglu, kadir; MAVİ, Betül; Akkaş, Ayşe

    2011-01-01

    In the production of concrete besides sand, gravel, crushed stone agrega is the main materials. It occupies about 60-75% of concrete in volume. If the specific gravity of agrega is higher than 4000 kg/m3, it is known as heavy agrega and in order to produce heavyweight concrete heavy agrega should be used in concrete mixture. This study, the radiation absorption properties of concrete in determining who was to see how they affect the properties of barite absorption rate changes. In this study,...

  1. A Novel Radiation Shielding Material Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In order to safely explore space, humans must be protected from radiation. There are 2 predominant sources of extraterrestrial ionizing radiation, namely, Galactic...

  2. The Space Radiation: Nature, Biological Effects and Shielding

    Science.gov (United States)

    Muradian, Kh.

    The latest findings in origin, biological effects and shielding of the space ionizing radiation (SIR) are reviewed. It is stressed that after the impending implementation of artificial gravity, SIR could become the most serious concern for deep space travelers. SIR is more effective in induction of the genome- and cell-associated damages, compared with the conventional radioactive sources. The shielding of SIR is augmented due to the secondary spallation δ-radiation and possible cooperation with weightlessness and other negative impacts of a space flight. The panspermia concept postulating the existence of living organisms, e.g. bacterial spores, in space and their natural interplanetary transportation is discussed.

  3. Novel Concepts for Radiation Shielding Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — It is critical that safety factors be maximized with respect to long duration, extraterrestrial space flight. Any significant improvement in radiation protection...

  4. Radiation shielding properties of a novel cement–basalt mixture for nuclear energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Ipbüker, Cagatay; Nulk, Helena; Gulik, Volodymyr [University of Tartu, Institute of Physics (Estonia); Biland, Alex [HHK Technologies, Houston (United States); Tkaczyk, Alan Henry, E-mail: alan@ut.ee [University of Tartu, Institute of Physics (Estonia)

    2015-04-01

    Highlights: • Basalt fiber is a relatively cheap material that can be used as reinforcement. • Gamma-ray attenuation remains relatively stable with addition of basalt fiber. • Neutron attenuation remains relatively stable with addition of basalt fiber. • Cement–basalt mixture has a good potential for use in nuclear energy applications. - Abstract: The radiation shielding properties of a new proposed building material, a novel cement–basalt fiber mixture (CBM), are investigated. The authors analyze the possibility of this material to be a viable substitute to outgoing materials in nuclear energy applications, which will lead to a further sustained development of nuclear energy in the future. This computational study involves four types of concrete with various amounts of basalt fiber in them. The gamma-ray shielding characteristics of proposed CBM material are investigated with the help of WinXCom program, whereas the neutron shielding characteristics are computed by the Serpent code. For gamma-ray shielding, we find that the attenuation coefficients of concretes with basalt fibers are not notably influenced by the addition of fibers. For neutron shielding, additional basalt fiber in mixture presents negligible effect on neutron radiation shielding. With respect to radiation shielding, it can be concluded that basalt fibers have good potential as an addition to heavyweight concrete for nuclear energy applications.

  5. The Magnetic and Shielding Effects of Ring Current on Radiation Belt Dynamics

    Science.gov (United States)

    Fok, Mei-Ching

    2012-01-01

    The ring current plays many key roles in controlling magnetospheric dynamics. A well-known example is the magnetic depression produced by the ring current, which alters the drift paths of radiation belt electrons and may cause significant electron flux dropout. Little attention is paid to the ring current shielding effect on radiation belt dynamics. A recent simulation study that combines the Comprehensive Ring Current Model (CRCM) with the Radiation Belt Environment (RBE) model has revealed that the ring current-associated shielding field directly and/or indirectly weakens the relativistic electron flux increase during magnetic storms. In this talk, we will discuss how ring current magnetic field and electric shielding moderate the radiation belt enhancement.

  6. Radiation Shielding of Lunar Regolith/Polyethylene Composites and Lunar Regolith/Water Mixtures

    Science.gov (United States)

    Johnson, Quincy F.; Gersey, Brad; Wilkins, Richard; Zhou, Jianren

    2011-01-01

    Space radiation is a complex mixed field of ionizing radiation that can pose hazardous risks to sophisticated electronics and humans. Mission planning for lunar exploration and long duration habitat construction will face tremendous challenges of shielding against various types of space radiation in an attempt to minimize the detrimental effects it may have on materials, electronics, and humans. In late 2009, the Lunar Crater Observation and Sensing Satellite (LCROSS) discovered that water content in lunar regolith found in certain areas on the moon can be up to 5.6 +/-2.8 weight percent (wt%) [A. Colaprete, et. al., Science, Vol. 330, 463 (2010). ]. In this work, shielding studies were performed utilizing ultra high molecular weight polyethylene (UHMWPE) and aluminum, both being standard space shielding materials, simulated lunar regolith/ polyethylene composites, and simulated lunar regolith mixed with UHMWPE particles and water. Based on the LCROSS findings, radiation shielding experiments were conducted to test for shielding efficiency of regolith/UHMWPE/water mixtures with various percentages of water to compare relative shielding characteristics of these materials. One set of radiation studies were performed using the proton synchrotron at the Loma Linda Medical University where high energy protons similar to those found on the surface of the moon can be generated. A similar experimental protocol was also used at a high energy spalation neutron source at Los Alamos Neutron Science Center (LANSCE). These experiments studied the shielding efficiency against secondary neutrons, another major component of space radiation field. In both the proton and neutron studies, shielding efficiency was determined by utilizing a tissue equivalent proportional counter (TEPC) behind various thicknesses of shielding composite panels or mixture materials. Preliminary results from these studies indicated that adding 2 wt% water to regolith particles could increase shielding of

  7. Adaptive planning using megavoltage fan-beam CT for radiation therapy with testicular shielding

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Poonam [Department of Human Oncology, University of Wisconsin, Madison, Madison, WI (United States); Department of Medical Physics, University of Wisconsin, Madison, Madison, WI (United States); School of Advance Sciences, Vellore Institue of Technology University, Vellore, Tamil Nadu (India); Kozak, Kevin [Department of Human Oncology, University of Wisconsin, Madison, Madison, WI (United States); Tolakanahalli, Ranjini [Department of Human Oncology, University of Wisconsin, Madison, Madison, WI (United States); Department of Medical Physics, University of Wisconsin, Madison, Madison, WI (United States); Ramasubramanian, V. [School of Advance Sciences, Vellore Institue of Technology University, Vellore, Tamil Nadu (India); Paliwal, Bhudatt R. [Department of Human Oncology, University of Wisconsin, Madison, Madison, WI (United States); Department of Medical Physics, University of Wisconsin, Madison, Madison, WI (United States); University of Wisconsin, Riverview Cancer Centre, Wisconsin Rapids, WI (United States); Welsh, James S. [Department of Human Oncology, University of Wisconsin, Madison, Madison, WI (United States); Department of Medical Physics, University of Wisconsin, Madison, Madison, WI (United States); Rong, Yi, E-mail: rong@humonc.wisc.edu [Department of Human Oncology, University of Wisconsin, Madison, Madison, WI (United States); University of Wisconsin, Riverview Cancer Centre, Wisconsin Rapids, WI (United States)

    2012-07-01

    This study highlights the use of adaptive planning to accommodate testicular shielding in helical tomotherapy for malignancies of the proximal thigh. Two cases of young men with large soft tissue sarcomas of the proximal thigh are presented. After multidisciplinary evaluation, preoperative radiation therapy was recommended. Both patients were referred for sperm banking and lead shields were used to minimize testicular dose during radiation therapy. To minimize imaging artifacts, kilovoltage CT (kVCT) treatment planning was conducted without shielding. Generous hypothetical contours were generated on each 'planning scan' to estimate the location of the lead shield and generate a directionally blocked helical tomotherapy plan. To ensure the accuracy of each plan, megavoltage fan-beam CT (MVCT) scans were obtained at the first treatment and adaptive planning was performed to account for lead shield placement. Two important regions of interest in these cases were femurs and femoral heads. During adaptive planning for the first patient, it was observed that the virtual lead shield contour on kVCT planning images was significantly larger than the actual lead shield used for treatment. However, for the second patient, it was noted that the size of the virtual lead shield contoured on the kVCT image was significantly smaller than the actual shield size. Thus, new adaptive plans based on MVCT images were generated and used for treatment. The planning target volume was underdosed up to 2% and had higher maximum doses without adaptive planning. In conclusion, the treatment of the upper thigh, particularly in young men, presents several clinical challenges, including preservation of gonadal function. In such circumstances, adaptive planning using MVCT can ensure accurate dose delivery even in the presence of high-density testicular shields.

  8. Determining optical and radiation characteristics of cathode ray tubes' glass to be reused as radiation shielding glass

    Science.gov (United States)

    Zughbi, A.; Kharita, M. H.; Shehada, A. M.

    2017-07-01

    A new method of recycling glass of Cathode Ray Tubes (CRTs) has been presented in this paper. The glass from CRTs suggested being used as raw materials for the production of radiation shielding glass. Cathode ray tubes glass contains considerable amounts of environmentally hazardous toxic wastes, namely heavy metal oxides such as lead oxide (PbO). This method makes CRTs glass a favorable choice to be used as raw material for Radiation Shielding Glass and concrete. The heavy metal oxides increase its density, which make this type of glass nearly equivalent to commercially available shielding glass. CRTs glass have been characterized to determine heavy oxides content, density, refractive index, and radiation shielding properties for different Gamma-Ray energies. Empirical methods have been used by using the Gamma-Ray source cobalt-60 and computational method by using the code XCOM. Measured and calculated values were in a good compatibility. The effects of irradiation by gamma rays of cobalt-60 on the optical transparency for each part of the CRTs glass have been studied. The Results had shown that some parts of CRTs glass have more resistant to Gamma radiation than others. The study had shown that the glass of cathode ray tubes could be recycled to be used as radiation shielding glass. This proposed use of CRT glass is only limited to the available quantity of CRT world-wide.

  9. Investigation of ionizing radiation shielding effectiveness of decorative building materials used in Bangladeshi dwellings

    Science.gov (United States)

    Yesmin, Sabina; Sonker Barua, Bijoy; Uddin Khandaker, Mayeen; Tareque Chowdhury, Mohammed; Kamal, Masud; Rashid, M. A.; Miah, M. M. H.; Bradley, D. A.

    2017-11-01

    Following the rapid growing per capita income, a major portion of Bangladeshi dwellers is upgrading their non-brick houses by rod-cement-concrete materials and simultaneously curious to decorate the houses using luxurious marble stones. Present study was undertaken to investigate the gamma-ray attenuation co-efficient of decorative marble materials leading to their suitability as shielding of ionizing radiation. A number of commercial grades decorative marble stones were collected from home and abroad following their large-scale uses. A well-shielded HPGe γ-ray spectrometer combined with associated electronics was used to evaluate the mass attenuation coefficients of the studied materials for high energy photons. Some allied parameters such as half-value layer and radiation protection efficacy of the investigated marbles were calculated. The results showed that among the studied samples, the marble 'Carrara' imported from Italy is suitable to be used as radiation shielding material.

  10. Radiation shielding properties of high performance concrete reinforced with basalt fibers infused with natural and enriched boron

    Energy Technology Data Exchange (ETDEWEB)

    Zorla, Eyüp; Ipbüker, Cagatay [University of Tartu, Institute of Physics (Estonia); Biland, Alex [US Basalt Corp., Houston (United States); Kiisk, Madis [University of Tartu, Institute of Physics (Estonia); Kovaljov, Sergei [OÜ Basaltest, Tartu (Estonia); Tkaczyk, Alan H. [University of Tartu, Institute of Physics (Estonia); Gulik, Volodymyr, E-mail: volodymyr.gulik@gmail.com [Institute for Safety Problems of Nuclear Power Plants, Lysogirska 12, of. 201, 03028 Kyiv (Ukraine)

    2017-03-15

    Highlights: • Basalt fiber infused with natural and enriched boron in varying proportions. • Gamma-ray attenuation remains stable with addition of basalt-boron fiber. • Improvement in neutron shielding for nuclear facilities producing fast fission spectrum. • Basalt-boron fiber could decrease the shielding thickness in thermal spectrum reactors. - Abstract: The importance of radiation shielding is increasing in parallel with the expansion of the application areas of nuclear technologies. This study investigates the radiation shielding properties of two types of high strength concrete reinforced with basalt fibers infused with 12–20% boron oxide, containing varying fractions of natural and enriched boron. The gamma-ray shielding characteristics are analyzed with the help of the WinXCom, whereas the neutron shielding characteristics are modeled and computed by Monte Carlo Serpent code. For gamma-ray shielding, the attenuation coefficients of the studied samples do not display any significant variation due to the addition of basalt-boron fibers at any mixing proportion. For neutron shielding, the addition of basalt-boron fiber has negligible effects in the case of very fast neutrons (14 MeV), but it could considerably improve the neutron shielding of concrete for nuclear facilities producing a fast fission spectrum (e.g. with reactors as BN-800, FBTR) and thermal neutron spectrum (Light Water Reactors (LWR)). It was also found that basalt-boron fiber could decrease the thickness of radiation shielding material in thermal spectrum reactors.

  11. EFFICACY OF AN ADDITIONAL MOBILE LEADED SHIELD ON OPERATOR RADIATION DURING PERCUTANEOUS CORONARY ANGIOGRAPHY.

    Science.gov (United States)

    Luçon, Adrien; Ghrairi, Ayoub; Lecoq, Guillaume; Idali, Moussa; Huret, Bruno; Richard, Pascal; Morelle, Jean-François

    2017-04-15

    Operator radiation protection during percutaneous coronary angiography (CA) is a growing concern in the catheterisation laboratory (cath lab). The purpose of this study was to evaluate the efficacy of an additional mobile leaded shield on operator radiation exposure during diagnostic CA. The study involved two operators from the same cath lab and patients scheduled for diagnostic coronary catheterisation over a period of 2 months. Procedures were performed with standard radiation equipment during the first month. An additional mobile lead shield was added during the second month. Radiation exposure was measured by three dosimeters positioned on the operator's left hand, on their chest under the lead apron and on lead glasses. The intra-operator results were compared. Ninety-nine per cent of the procedures were carried out by radial access. For Operators 1 and 2, the mobile shield, respectively, decreased the radiation dose to the eyes by 43 and 33 % and to the hands by 61 and 83 %. Thorax dose was less than the minimum measurable dose (leaded shield, combined with standard preventive measures, seems to be an effective additional option to reduce the radiation exposure during diagnostic CA. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Characterization and biocompatibility studies of lead free X-ray shielding polymer composite for healthcare application

    Science.gov (United States)

    Singh, Anil Kumar; Singh, Rakesh Kumar; Sharma, Bhupesh; Tyagi, Ajay Kumar

    2017-09-01

    Lead based X-ray shielding systems are widely being used in healthcare and radiation processing centers to protect technicians, operators and patients from unwanted exposure to ionizing radiation. However, the use of lead is avoided mainly due to its toxic effects on human health and environment, and also discomfort due to heavier in weight. Hence, production of non-toxic, environment friendly, lead-free X-ray shielding system with less weight and good radiation shielding efficiency compared to conventional lead-based shielding systems is a challenging issue and need of the day. The objectives of present study are to develop, characterize and establish synergy of the materials making radiation shielding composition and their biocompatibility without compromising on radiation shielding efficiency and physico-mechanical attributes vis-à-vis lead based systems.

  13. A handy method for estimating radiation streaming through holes in shield assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Iida, H.; Santoro, R.T.; Valenza, D.; Khripunov, V. [Int. Thermonuclear Exp. Reactor, Garching (Germany)

    1998-10-01

    A `handy method` has been developed for performing quick estimates of radiation streaming through cylindrical and rectangular holes in shield assemblies. Quick estimates are often needed during conceptual studies or detailed design of nuclear plants. For example, ITER has a large number of penetrations in the blanket and vacuum vessel and biological shield. This method estimates the levels of radiation that leaks through these holes as well as the magnitude of the fluxes along the hole wall. Results obtained using the `handy method` are in good agreement with 3-D Monte Carlo calculations suggesting that the method provides a practical tool for streaming analysis. (orig.) 7 refs.

  14. A Monte Carlo study of I-125 prostate brachytherapy with gold nanoparticles: dose enhancement with simultaneous rectal dose sparing via radiation shielding

    Science.gov (United States)

    Brivio, D.; Nguyen, P. L.; Sajo, E.; Ngwa, W.; Zygmanski, P.

    2017-03-01

    We investigate via Monte Carlo simulations a new 125I brachytherapy treatment technique for high-risk prostate cancer patients via injection of Au nanoparticle (AuNP) directly into the prostate. The purpose of using the nanoparticles is to increase the therapeutic index via two synergistic effects: enhanced energy deposition within the prostate and simultaneous shielding of organs at risk from radiation escaping from the prostate. Both uniform and non-uniform concentrations of AuNP are studied. The latter are modeled considering the possibility of AuNP diffusion after the injection using brachy needles. We study two extreme cases of coaxial AuNP concentrations: centered on brachy needles and centered half-way between them. Assuming uniform distribution of 30 mg g-1 of AuNP within the prostate, we obtain a dose enhancement larger than a factor of 2 to the prostate. Non-uniform concentration of AuNP ranging from 10 mg g-1 and 66 mg g-1 were studied. The higher the concentration in a given region of the prostate the greater is the enhancement therein. We obtain the highest dose enhancement when the brachytherapy needles are coincident with AuNP injection needles but, at the same time, the regions in the tail are colder (average dose ratio of 0.7). The best enhancement uniformity is obtained with the seeds in the tail of the AuNP distribution. In both uniform and non-uniform cases the urethra and rectum receive less than 1/3 dose compared to an analog treatment without AuNP. Remarkably, employing AuNP not only significantly increases dose to the target but also decreases dose to the neighboring rectum and even urethra, which is embedded within the prostate. These are mutually interdependent effects as more enhancement leads to more shielding and vice-versa. Caution must be paid since cold spot or hot spots may be created if the AuNP concentration versus seed position is not properly distributed respect to the seed locations.

  15. Chemistry and radiative shielding in star-forming galactic discs

    Science.gov (United States)

    Safranek-Shrader, Chalence; Krumholz, Mark R.; Kim, Chang-Goo; Ostriker, Eve C.; Klein, Richard I.; Li, Shule; McKee, Christopher F.; Stone, James M.

    2017-02-01

    To understand the conditions under which dense, molecular gas is able to form within a galaxy, we post-process a series of three-dimensional galactic-disc-scale simulations with ray-tracing-based radiative transfer and chemical network integration to compute the equilibrium chemical and thermal state of the gas. In performing these simulations, we vary a number of parameters, such as the interstellar radiation field strength, vertical scaleheight of stellar sources, and cosmic ray flux, to gauge the sensitivity of our results to these variations. Self-shielding permits significant molecular hydrogen (H2) abundances in dense filaments around the disc mid-plane, accounting for approximately ˜10-15 per cent of the total gas mass. Significant CO fractions only form in the densest, nH≳ 10^3 cm^{-3}, gas where a combination of dust, H2, and self-shielding attenuates the far-ultraviolet background. We additionally compare these ray-tracing-based solutions to photochemistry with complementary models where photoshielding is accounted for with locally computed prescriptions. With some exceptions, these local models for the radiative shielding length perform reasonably well at reproducing the distribution and amount of molecular gas as compared with a detailed, global ray-tracing calculation. Specifically, an approach based on the Jeans length with a T = 40 K temperature cap performs the best in regard to a number of different quantitative measures based on the H2 and CO abundances.

  16. Shielding considerations for the small animal radiation research platform (SARRP).

    Science.gov (United States)

    Sayler, Elaine; Dolney, Derek; Avery, Stephen; Koch, Cameron

    2013-05-01

    The Small Animal Radiation Research Platform (SARRP) is a commercially available platform designed to deliver conformal, image-guided radiation to small animals using a dual-anode kV x-ray source. At the University of Pennsylvania, a free-standing 2 m enclosure was designed to shield the SARRP according to federal code regulating cabinet x-ray systems. The initial design consisted of 4.0-mm-thick lead for all secondary barriers and proved wholly inadequate. Radiation levels outside the enclosure were 15 times higher than expected. Additionally, the leakage appeared to be distributed broadly within the enclosure, so concern arose that a subject might receive significant doses outside the intended treatment field. Thus, a detailed analysis was undertaken to identify and block all sources of leakage. Leakage sources were identified by Kodak X-OmatV (XV) film placed throughout the enclosure. Radiation inside the enclosure was quantified using Gafchromic film. Outside the enclosure, radiation was measured using a survey meter. Sources of leakage included (1) an unnecessarily broad beam exiting the tube, (2) failure of the secondary collimator to confine the primary beam entirely, (3) scatter from the secondary collimator, (4) lack of beam-stop below the treatment volume, and (5) incomplete shielding of the x-ray tube. The exit window was restricted, and a new collimator was designed to address problems (1-3). A beam-stop and additional tube shielding were installed. These modifications reduced internal scatter by more than 100-fold. Radiation outside the enclosure was reduced to levels compliant with federal regulations, provided the SARRP is operated using tube potentials of 175 kV or less. In addition, these simple and relatively inexpensive modifications eliminate the possibility of exposing a larger animal (such as a rat) to significant doses outside the treatment field.

  17. A Comprehensive Study on Gamma Rays and Fast Neutron Sensing Properties of GAGOC and CMO Scintillators for Shielding Radiation Applications

    Directory of Open Access Journals (Sweden)

    Shams A. M. Issa

    2017-01-01

    Full Text Available The WinXCom program has been used to calculate the mass attenuation coefficients (μm, effective atomic numbers (Zeff, effective electron densities (Nel, half-value layer (HVL, and mean free path (MFP in the energy range 1 keV–100 GeV for Gd3Al2Ga3O12Ce (GAGOC and CaMoO4 (CMO scintillator materials. The geometrical progression (G-P method has been used to compute the exposure buildup factors (EBF and gamma ray energy absorption (EABF in the photon energy range 0.015–15 MeV and up to a 40 penetration depth (mfp. In addition, the values of the removal cross section for a fast neutron ∑R have been calculated. The computed data observes that GAGOC showed excellent γ-rays and neutrons sensing a response in the broad energy range. This work could be useful for nuclear radiation sensors, detectors, nuclear medicine applications (medical imaging and mammography, nuclear engineering, and space technology.

  18. Wedge Diffraction as an Instance of Radiative Shielding

    CERN Document Server

    Grzesik, J A

    2016-01-01

    The celebrated Sommerfeld wedge diffraction solution is reexamined from a null interior field perspective. Exact surface currents provided by that solution, when considered as disembodied half-plane laminae radiating into an ambient, uniform space both inside and outside the wedge proper, do succeed in reconstituting both a specular, mirror field above the exposed face, and a shielding plane-wave field of a sign opposite to that of the incoming excitation which, under superposition, creates both the classical, geometric-optics shadow, and a strictly null interior field at the dominant, plane-wave level. Both mirror and shadow radiated fields are controlled by the residue at just one simple pole encountered during a spectral radiative field assembly, fixed in place by incidence direction $\\phi_{0}$ as measured from the exposed face. The radiated fields further provide diffractive contributions drawn from two saddle points that track observation angle $\\phi.$ Even these, more or less asymptotic contributions, a...

  19. ACCURATE TEMPERATURE MEASUREMENTS IN A NATURALLY-ASPIRATED RADIATION SHIELD

    Energy Technology Data Exchange (ETDEWEB)

    Kurzeja, R.

    2009-09-09

    Experiments and calculations were conducted with a 0.13 mm fine wire thermocouple within a naturally-aspirated Gill radiation shield to assess and improve the accuracy of air temperature measurements without the use of mechanical aspiration, wind speed or radiation measurements. It was found that this thermocouple measured the air temperature with root-mean-square errors of 0.35 K within the Gill shield without correction. A linear temperature correction was evaluated based on the difference between the interior plate and thermocouple temperatures. This correction was found to be relatively insensitive to shield design and yielded an error of 0.16 K for combined day and night observations. The correction was reliable in the daytime when the wind speed usually exceeds 1 m s{sup -1} but occasionally performed poorly at night during very light winds. Inspection of the standard deviation in the thermocouple wire temperature identified these periods but did not unambiguously locate the most serious events. However, estimates of sensor accuracy during these periods is complicated by the much larger sampling volume of the mechanically-aspirated sensor compared with the naturally-aspirated sensor and the presence of significant near surface temperature gradients. The root-mean-square errors therefore are upper limits to the aspiration error since they include intrinsic sensor differences and intermittent volume sampling differences.

  20. Pb-free Radiation Shielding Glass Using Coal Fly Ash

    Directory of Open Access Journals (Sweden)

    Watcharin Rachniyom

    2015-12-01

    Full Text Available In this work, Pb-free shielding glass samples were prepared by the melt quenching technique using subbituminous fly ash (SFA composed of xBi2O3 : (60-xB2O3 : 10Na2O : 30SFA (where x = 10, 15, 20, 25, 30 and 35 by wt%. The samples were investigated for their physical and radiation shielding properties. The density and hardness were measured. The results showed that the density increased with the increase of Bi2O3 content. The highest value of hardness was observed for glass sample with 30 wt% of Bi2O3 concentration. The samples were investigated under 662 keV gamma ray and the results were compared with theoretical calculations. The values of the mass attenuation coefficient (μm, the atomic cross section (σe and the effective atomic number (Zeff were found to increase with an increase of the Bi2O3 concentration and were in good agreement with the theoretical calculations. The best results for the half-value layer (HVL were observed in the sample with 35 wt% of Bi2O3 concentration, better than the values of barite concrete. These results demonstrate the viability of using coal fly ash waste for radiation shielding glass without PbO in the glass matrices.

  1. Operator Radiation and the Efficacy of Ceiling-Suspended Lead Screen Shielding during Coronary Angiography: An Anthropomorphic Phantom Study Using Real-Time Dosimeters

    Science.gov (United States)

    Jia, Qianjun; Chen, Ziman; Jiang, Xianxian; Zhao, Zhenjun; Huang, Meiping; Li, Jiahua; Zhuang, Jian; Liu, Xiaoqing; Hu, Tianyu; Liang, Wensheng

    2017-02-01

    Operator radiation and the radiation protection efficacy of a ceiling-suspended lead screen were assessed during coronary angiography (CA) in a catheterization laboratory. An anthropomorphic phantom was placed under the X-ray beam to simulate patient attenuation in eight CA projections. Using real-time dosimeters, radiation dose rates were measured on models mimicking a primary operator (PO) and an assistant. Subsequently, a ceiling-suspended lead screen was placed in three commonly used positions to compare the radiation protection efficacy. The radiation exposure to the PO was 2.3 to 227.9 (mean: 67.2 ± 49.0) μSv/min, with the left anterior oblique (LAO) 45°/cranial 25° and cranial 25° projections causing the highest and the lowest dose rates, respectively. The assistant experienced significantly less radiation overall (mean: 20.1 ± 19.6 μSv/min, P RAO) 30° and cranial 25° projections resulting in the highest and lowest exposure levels, respectively. Combined with table-side shielding, the ceiling-suspended lead screen reduced the radiation to the PO by 76.8%, 81.9% and 93.5% when placed close to the patient phantom, at the left side and close to the PO, respectively, and reduced the radiation to the assistant by 70.3%, 76.7% and 90.0%, respectively. When placed close to the PO, a ceiling-suspended lead screen provides substantial radiation protection during CA.

  2. Method and system for determining radiation shielding thickness and gamma-ray energy

    Science.gov (United States)

    Klann, Raymond T.; Vilim, Richard B.; de la Barrera, Sergio

    2015-12-15

    A system and method for determining the shielding thickness of a detected radiation source. The gamma ray spectrum of a radiation detector is utilized to estimate the shielding between the detector and the radiation source. The determination of the shielding may be used to adjust the information from known source-localization techniques to provide improved performance and accuracy of locating the source of radiation.

  3. Meeting the Grand Challenge of Protecting Astronaut's Health: Electrostatic Active Space Radiation Shielding for Deep Space Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This study will seek to test and validate an electrostatic gossamer structure to provide radiation shielding. It will provide guidelines for energy requirements,...

  4. Neutron radiation shielding properties of polymer incorporated self compacting concrete mixes.

    Science.gov (United States)

    Malkapur, Santhosh M; Divakar, L; Narasimhan, Mattur C; Karkera, Narayana B; Goverdhan, P; Sathian, V; Prasad, N K

    2017-07-01

    In this work, the neutron radiation shielding characteristics of a class of novel polymer-incorporated self-compacting concrete (PISCC) mixes are evaluated. Pulverized high density polyethylene (HDPE) material was used, at three different reference volumes, as a partial replacement to river sand in conventional concrete mixes. By such partial replacement of sand with polymer, additional hydrogen contents are incorporated in these concrete mixes and their effect on the neutron radiation shielding properties are studied. It has been observed from the initial set of experiments that there is a definite trend of reductions in the neutron flux and dose transmission factor values in these PISCC mixes vis-à-vis ordinary concrete mix. Also, the fact that quite similar enhanced shielding results are recorded even when reprocessed HDPE material is used in lieu of the virgin HDPE attracts further attention. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. 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

  6. A study on the shielding of lodine 131 using Monte Carlo Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Dong Gun; Yang, Seoung Oh; Kim, Jung Ki; Lee, Sang Ho; Choi, Hyung Seok; Bae, Cheol Woo [Dongnam Institute of Radiological and Medical Sciences Cancer Center, Busan (Korea, Republic of)

    2014-06-15

    This study was designated to investigate the Bremsstrahlung and radiation dose by beta rays. Radiation attenuation from I-131 treatment ward was analyzed using radio protective apron. Shielding materials which is included lead or water were simulated in Monte Carlo Simulation then the spectrum on interaction was analyzed. The shielding materials were categorized according to the thickness. 0.25 mm and 0.5 mm thick lead and 0.1 mm and 0.2 mm thick water shielding materials were configured in Monte Carlo Simulation for this study. Only lead shielding method and water plus lead shielding method were carried. As a results, when 0.5 mm thick lead shielding method was performed, the radiation dose was similar to the results with water plus lead shielding method. In case of using 0.25 mm thick lead shielding, the shielding effect was somewhat less. However, that shielding method cause dose reduction of about 60% compare with non-shielding material.

  7. Radiation shielding calculations for MuCool test area at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Igor Rakhno; Carol Johnstone

    2004-05-26

    The MuCool Test Area (MTA) is an intense primary beam facility derived directly from the Fermilab Linac to test heat deposition and other technical concerns associated with the liquid hydrogen targets being developed for cooling intense muon beams. In this shielding study the results of Monte Carlo radiation shielding calculations performed using the MARS14 code for the MuCool Test Area and including the downstream portion of the target hall and berm around it, access pit, service building, and parking lot are presented and discussed within the context of the proposed MTA experimental configuration.

  8. Metal Hydrides, MOFs, and Carbon Composites as Space Radiation Shielding Mitigators

    Science.gov (United States)

    Atwell, William; Rojdev, Kristina; Liang, Daniel; Hill, Matthew

    2014-01-01

    Recently, metal hydrides and MOFs (Metal-Organic Framework/microporous organic polymer composites - for their hydrogen and methane storage capabilities) have been studied with applications in fuel cell technology. We have investigated a dual-use of these materials and carbon composites (CNT-HDPE) to include space radiation shielding mitigation. In this paper we present the results of a detailed study where we have analyzed 64 materials. We used the Band fit spectra for the combined 19-24 October 1989 solar proton events as the input source term radiation environment. These computational analyses were performed with the NASA high energy particle transport/dose code HZETRN. Through this analysis we have identified several of the materials that have excellent radiation shielding properties and the details of this analysis will be discussed further in the paper.

  9. Study of Radiation Shielding Properties of selected Tropical Wood Species for X-rays in the 50-150 keV Range

    Directory of Open Access Journals (Sweden)

    S. Aggrey-Smith

    2016-03-01

    Full Text Available This paper compares the attenuation coefficients of 20 tropical hard wood species based on their linear and mass attenuation and half value layer (HVL properties for X-rays of energy 50–150 keV using a narrow collimated beam from a Cs-137 source. The narrow collimated beam method made corrections from multiple and small-angle scatterings of photons unnecessary. The attenuation depended on the chemical composition and densities of the wood species. The linear attenuation coefficients of wood species at 50–150 keV were highest for Pterygota macrocarpa (4.53 m−1 and lowest for Antiaris africana (1.24 m−1; the mass attenuation coefficient was highest for Triplochiton scleroxylon (17.62 m2/kg and lowest for Nesogordonia papaverifera (2.27 m2/kg.The HVL was highest for Antiaris africana (0.27 m and lowest for Pterygota macrocarpa (0.149 m. Pterygota macrocarpa of about 0.36 m thickness could serve as a more affordable radiation shielding material against secondary scatter and leakage radiations in place of lead, copper or concrete for low X-ray radiations up to 150 keV.

  10. Comparative study of silicate glasses containing Bi{sub 2}O{sub 3}, PbO and BaO: Radiation shielding and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Kirdsiri, K. [Department of Physics, Faculty of Science, King Mongkut' s University of Technology Thonburi, Bangkok 10140 (Thailand); Thailand Center of Excellence in Physics, CHE, Ministry of Education, Bangkok 10400 (Thailand); Center of Excellence in Glass Technology and Materials Science (CEGM), Faculty of Science and Technology, Nakhon Pathom Rajabhat University, Nakorn Pathom 73000 (Thailand); Kaewkhao, J., E-mail: mink052@yahoo.com [Thailand Center of Excellence in Physics, CHE, Ministry of Education, Bangkok 10400 (Thailand); Center of Excellence in Glass Technology and Materials Science (CEGM), Faculty of Science and Technology, Nakhon Pathom Rajabhat University, Nakorn Pathom 73000 (Thailand); Chanthima, N. [Department of Physics, Faculty of Science, King Mongkut' s University of Technology Thonburi, Bangkok 10140 (Thailand); Limsuwan, P. [Department of Physics, Faculty of Science, King Mongkut' s University of Technology Thonburi, Bangkok 10140 (Thailand); Center of Excellence in Glass Technology and Materials Science (CEGM), Faculty of Science and Technology, Nakhon Pathom Rajabhat University, Nakorn Pathom 73000 (Thailand)

    2011-06-15

    Research highlights: > We change Bi{sub 2}O{sub 3}, PbO and BaO concentration in silicate glasses. > The densities of Bi{sub 2}O{sub 3} glasses more than PbO glasses and BaO glasses. > The Um of Bi{sub 2}O{sub 3} glasses and PbO glasses are comparable and more than BaO glasses. > This suggests that Bi{sub 2}O{sub 3} can replace PbO in radiation shielding glasses. - Abstract: The radiation shielding and optical properties of xBi{sub 2}O{sub 3}:(100-x)SiO{sub 2}, xPbO:(100-x)SiO{sub 2} and xBaO:(100-x)SiO{sub 2} glass systems (where 30 {<=} x {<=} 70 is the composition by weight%) have been investigated. Total mass attenuation coefficients ({mu}{sub m}) of glasses at 662 keV were improved by increasing their Bi{sub 2}O{sub 3} and PbO content, which raised the photoelectric absorption in glass matrices. Raising the BaO content to the same fraction range, however, brought no significant change to {mu}{sub m}. These results indicate that photon is strongly attenuated in Bi{sub 2}O{sub 3} and PbO containing glasses, and but not in BaO containing glass. The results from the optical absorption spectra show an edge that was not sharply defined; clearly indicating the amorphous nature of glass samples. It is observed that the cutoff wavelength for Bi{sub 2}O{sub 3} containing glass was longer than PbO and BaO containing glasses.

  11. Radiation Resistance Test of Wireless Sensor Node and the Radiation Shielding Calculation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Liqan; Sur, Bhaskar [Atomic Energy of Canada Limited, Ontario (Canada); Wang, Quan [University of Western Ontario, Ontario (Canada); Deng, Changjian [The University of Electronic Science and Technology, Chengdu (China); Chen, Dongyi; Jiang, Jin [Applied Physics Branch, Ontario (Korea, Republic of)

    2014-08-15

    A wireless sensor network (WSN) is being developed for nuclear power plants. Amongst others, ionizing radiation resistance is one essential requirement for WSN to be successful. This paper documents the work done in Chalk River Laboratories of Atomic Energy of Canada Limited (AECL) to test the resistance to neutron and gamma radiation of some WSN nodes. The recorded dose limit that the nodes can withstand before being damaged by the radiation is compared with the radiation environment inside a typical CANDU (CANada Deuterium Uranium) power plant reactor building. Shielding effects of polyethylene, cadmium and lead to neutron and gamma radiations are also analyzed using MCNP simulation. The shielding calculation can be a reference for the node case design when high dose rate or accidental condition (like Fukushima) is to be considered.

  12. A study on the shielding element using Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Jeong [Dept. of Radiology, Konkuk University Medical Center, Seoul (Korea, Republic of); Shim, Jae Goo [Dept. of Radiologic Technology, Daegu Health College, Daegu (Korea, Republic of)

    2017-06-15

    In this research, we simulated the elementary star shielding ability using Monte Carlo simulation to apply medical radiation shielding sheet which can replace existing lead. In the selection of elements, mainly elements and metal elements having a large atomic number, which are known to have high shielding performance, recently, various composite materials have improved shielding performance, so that weight reduction, processability, In consideration of activity etc., 21 elements were selected. The simulation tools were utilized Monte Carlo method. As a result of simulating the shielding performance by each element, it was estimated that the shielding ratio is the highest at 98.82% and 98.44% for tungsten and gold.

  13. Shielding Factors for Gamma Radiation from Activity Deposited on Structures and Ground Surfaces

    DEFF Research Database (Denmark)

    Jensen, Per Hedemann

    1985-01-01

    A computer model DEPSHIELD for the calculation of shielding factors for gamma radiation at indoor residences in multistorey and single-family houses has been developed. The model is based on the exponential point kernel that links the radiation flux density at a given detector point to a point......-source strength. The radiation sources considered in the model are fallout radioactivity deposited on roofs, outer walls, and ground surfaces. For any combination of source strength on roof, outer wall, and ground surface, the model calculates shielding factors for specified photon energies. The input data...... it possible to determine the dose reduction effect from a decontamination of the different surfaces. The model has been used in a study of the consequences of land contamination of Danish territory after hypothetical core-melt accidents at the Barseback nuclear power plant in Sweden. The model has also been...

  14. A comparison of radiation shielding effectiveness of materials for highly elliptical orbits

    Science.gov (United States)

    Emmanuel, A.; Raghavan, J.; Harris, R.; Ferguson, P.

    2014-04-01

    The Canadian Space Agency (CSA) has proposed a Polar Communications and Weather (PCW) satellite mission, in conjunction with other partners. The PCW will provide essential communications and meteorological services to the Canadian Arctic, as well as space weather observations of in situ ionizing radiation along the orbit. The CSA has identified three potential Highly Elliptical Orbits (HEOs) for a PCW satellite constellation, Molniya, Modified Tundra and Triple Apogee (TAP), each having specific merits, which would directly benefit the performance/longevity of a PCW spacecraft. Radiation shielding effectiveness of various materials was studied for the three PCW orbit options to determine the feasibility of employing materials other than conventional aluminium to achieve a specified spacecraft shielding level with weight savings over aluminium. It was found that, depending on the orbit-specific radiation environment characteristics, the benefits of using polyethylene based materials is significant enough (e.g., 22% in Molniya for PE at 50 krad TID) to merit further investigation.

  15. Use of Existing CAD Models for Radiation Shielding Analysis

    Science.gov (United States)

    Lee, K. T.; Barzilla, J. E.; Wilson, P.; Davis, A.; Zachman, J.

    2015-01-01

    The utility of a radiation exposure analysis depends not only on the accuracy of the underlying particle transport code, but also on the accuracy of the geometric representations of both the vehicle used as radiation shielding mass and the phantom representation of the human form. The current NASA/Space Radiation Analysis Group (SRAG) process to determine crew radiation exposure in a vehicle design incorporates both output from an analytic High Z and Energy Particle Transport (HZETRN) code and the properties (i.e., material thicknesses) of a previously processed drawing. This geometry pre-process can be time-consuming, and the results are less accurate than those determined using a Monte Carlo-based particle transport code. The current work aims to improve this process. Although several Monte Carlo programs (FLUKA, Geant4) are readily available, most use an internal geometry engine. The lack of an interface with the standard CAD formats used by the vehicle designers limits the ability of the user to communicate complex geometries. Translation of native CAD drawings into a format readable by these transport programs is time consuming and prone to error. The Direct Accelerated Geometry -United (DAGU) project is intended to provide an interface between the native vehicle or phantom CAD geometry and multiple particle transport codes to minimize problem setup, computing time and analysis error.

  16. Early Results from the Advanced Radiation Protection Thick GCR Shielding Project

    Science.gov (United States)

    Norman, Ryan B.; Clowdsley, Martha; Slaba, Tony; Heilbronn, Lawrence; Zeitlin, Cary; Kenny, Sean; Crespo, Luis; Giesy, Daniel; Warner, James; McGirl, Natalie; hide

    2017-01-01

    The Advanced Radiation Protection Thick Galactic Cosmic Ray (GCR) Shielding Project leverages experimental and modeling approaches to validate a predicted minimum in the radiation exposure versus shielding depth curve. Preliminary results of space radiation models indicate that a minimum in the dose equivalent versus aluminum shielding thickness may exist in the 20-30 g/cm2 region. For greater shield thickness, dose equivalent increases due to secondary neutron and light particle production. This result goes against the long held belief in the space radiation shielding community that increasing shielding thickness will decrease risk to crew health. A comprehensive modeling effort was undertaken to verify the preliminary modeling results using multiple Monte Carlo and deterministic space radiation transport codes. These results verified the preliminary findings of a minimum and helped drive the design of the experimental component of the project. In first-of-their-kind experiments performed at the NASA Space Radiation Laboratory, neutrons and light ions were measured between large thicknesses of aluminum shielding. Both an upstream and a downstream shield were incorporated into the experiment to represent the radiation environment inside a spacecraft. These measurements are used to validate the Monte Carlo codes and derive uncertainty distributions for exposure estimates behind thick shielding similar to that provided by spacecraft on a Mars mission. Preliminary results for all aspects of the project will be presented.

  17. 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/cm2).

  18. Shielding and radiation protection at the SSRL 3 GeV injector

    Energy Technology Data Exchange (ETDEWEB)

    Ipe, N.E.; Liu, J.C.

    1991-12-01

    The Stanford Synchrotron Radiation Laboratory (SSRL) Injector is comprised of a linear accelerator (linac) capable of energies {le} 150 MeV, a 3 GeV booster synchrotron, and a beam line to transport the electrons into the storage ring SPEAR. The injector is shielded so that under normal operating conditions, the annual dose equivalent at the shield surface does not exceed 10 mSv. This paper describes the shielding and radiation protection at the injector.

  19. Evaluation of radiation shielding rate of lead aprons in nuclear medicine

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sang Hyun; Han, Beom Heui; Lee, Sang Ho [Dept. of Radiological Science, Seonam University, Asan (Korea, Republic of); Hong, Dong Heui [Dept. of Radiological Science, Far East University, Eumseong (Korea, Republic of); Kim, Gi Jin [Dept. of Nuclear Medicine, Konyang University Hospital, Daejeon (Korea, Republic of)

    2017-03-15

    Considering that the X-ray apron used in the department of radiology is also used in the department of nuclear medicine, the study aimed to analyze the shielding rate of the apron according to types of radioisotopes, thus γ ray energy, to investigate the protective effects. The radioisotopes used in the experiment were the top 5 nuclides in usage statistics {sup 99m}Tc, {sup 18}F, {sup 131}I, {sup 123}I, and {sup 201}Tl, and the aprons were lead equivalent 0.35 mmPb aprons currently under use in the department of nuclear medicine. As a result of experiments, average shielding rates of aprons were {sup 99m}Tc 31.59%, {sup 201}Tl 68.42%, and {sup 123}I 76.63%. When using an apron, the shielding rate of {sup 13}'1I actually resulted in average dose rate increase of 33.72%, and {sup 18}F showed an average shielding rate of –0.315%, showing there was almost no shielding effect. As a result, the radioisotopes with higher shielding rate of apron was in the descending order of {sup 123}I, {sup 201}Tl, {sup 99m}Tc, {sup 18}F, {sup 131}I. Currently, aprons used in the nuclear medicine laboratory are general X-ray aprons, and it is thought that it is not appropriate for nuclear medicine environment that utilizes γ rays. Therefore, development of nuclear medicine exclusive aprons suitable for the characteristics of radioisotopes is required in consideration of effective radiation protection and work efficiency of radiation workers.

  20. 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

  1. Development of simplified methods and data bases for radiation shielding calculations for concrete

    Energy Technology Data Exchange (ETDEWEB)

    Bhuiyan, S.I.; Roussin, R.W.; Lucius, J.L.; Marable, J.H.; Bartine, D.A.

    1986-06-01

    Two simplified methods have been developed which allow rapid and accurate calculations of the attenuation of neutrons and gamma rays through concrete shields. One method, called the BEST method, uses sensitivity coefficients to predict changes in the transmitted dose from a fission source that are due to changes in the composition of the shield. The other method uses transmission factors based on adjoint calculations to predict the transmitted dose from an arbitrary source incident on a given shield. The BEST method, utilizing an exponential molecule that is shown to be a significant improvement over the traditional linear model, has been successfully applied to slab shields of standard concrete and rebar concrete. It has also been tested for a special concrete that has been used in many shielding experiments at the ORNL Tower Shielding Facility, as well as for a deep-penetration sodium problem. A comprehensive data base of concrete sensitivity coefficients generated as part of this study is available for use in the BEST model. For problems in which the changes are energy independent, application of the model and data base can be accomplished with a desk calculator. Larger-scale calculations required for problems that are energy dependent are facilitated by employing a simple computer code, which is included, together with the data base and other calculational aids, in a data package that can be obtained from the ORNL Radiation Shielding Information Center (request DLC-102/CONSENT). The transmission factors used by the second method are a byproduct of the sensitivity calculations and are mathematically equivalent to the surface adjoint function phi*, which gives the dose equivalent transmitted through a slab of thickness T due to one particle incident on the surface in the gth energy group and jth direction. 18 refs., 1 fig., 50 tabs.

  2. Space Station Validation of Advanced Radiation-Shielding Polymeric Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In Subtopic X11.01, NASA has identified the need to develop advanced radiation-shielding materials and systems to protect humans from the hazards of space radiation...

  3. A Reinforcement for Multifunctional Composites for Non-Parasitic Radiation Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation shielding is a requirement to protect humans from the hazards of space radiation during NASA missions. Multifunctional materials have the potential to...

  4. Space Station Validation of Advanced Radiation-Shielding Polymeric Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In Subtopic X11-01, NASA has identified the need to develop advanced radiation-shielding materials and systems to protect humans from the hazards of space radiation...

  5. Radiation predictions and shielding calculations for RITS-6

    Energy Technology Data Exchange (ETDEWEB)

    Maenchen, John Eric [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); O' Malley, John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kensek, Ronald Patrick [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fan, Wesley C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bollinger, Lance [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2005-06-01

    The mission of Radiographic Integrated Test Stand-6 (RITS-6) facility is to provide the underlying science and technology for pulsed-power-driven flash radiographic X-ray sources for the National Nuclear Security Administration (NNSA). Flash X-ray radiography is a penetrating diagnostic to discern the internal structure in dynamic experiments. Short (~50 nanosecond (ns) duration) bursts of very high intensity Xrays from mm-scale source sizes are required at a variety of voltages to address this mission. RITS-6 was designed and is used to both develop the accelerator technology needed for these experiments and serves as the principal test stand to develop the high intensity electron beam diodes that generate the required X-ray sources. RITS is currently in operation with three induction cavities (RITS-3) with a maximum voltage output of 5.5 MV and is classified as a low hazard non-nuclear facility in accordance with CPR 400.1.1, Chapter 13, Hazards Identification/Analysis and Risk Management. The facility will be expanded from three to six cavities (RITS-6) effectively doubling the operating voltage. The increase in the operating voltage to above 10 MV has resulted in RITS-6 being classified as an accelerator facility. RITS-6 will come under DOE Order 420.2B, Safety of Accelerator Facilities. The hazards of RITS are detailed in the "Safety Assessment Document for the Radiographic Integrated Test Stand Facility." The principal non-industrial hazard is prompt x-ray radiation. As the operating voltage is increased, both the penetration power and the total amount (dose) of x-rays are increased, thereby increasing the risk to local personnel. Fixed site shielding (predominantly concrete walls and a steel/lead skyshine shield) is used to attenuate these x-rays and mitigate this risk. This SAND Report details the anticipated x-ray doses, the shielding design, and the anticipated x-ray doses external to this shielding structure both in areas where administrative access

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

    Energy Technology Data Exchange (ETDEWEB)

    Hondorp, H.L.

    1981-07-06

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

  7. A study on the characteristics of modified and novolac type epoxy resin based neutron shielding material

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Soo Haeng; Hong, Sun Seok; Oh, Seung Chul; Do, Jae Bum [Korea Atomic Energy Research Institute, Taejon (Korea)

    1998-10-01

    Because the exposure to radiation in the nuclear facilities can be fatal to human, it is important to reduce the radiation dose level to a tolerable level. The purpose of this study is to develop highly effective neutron shielding materials for the shipping and storage cask of radioactive materials or in the nuclear/radiation facilities. In this study, we developed modified and novolac type epoxy resin based neutron shielding materials and their various material properties, including neutron shielding ability, prolonged time heat resistance, thermal and mechanical properties were evaluated experimently. (author). 31 refs., 27 figs., 16 tabs.

  8. Composites with carbon nanotube for radiation shielding application

    Energy Technology Data Exchange (ETDEWEB)

    Fontainha, Críssia C.P.; Nunes, Modesto; Rosas, Víctor A., E-mail: crissia@gmail.com [Universidade Federal de Minas Gerais (IMA/UFMG), Belo Horizonte, MG (Brazil). Dept. de Anatomia e Imagem; Santos, Adelina P.; Furtado, Clascídia A.; Faria, Luiz O., E-mail: farialo@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2017-07-01

    Polymeric composites filled with attenuating metals and functionalized with carbon nanotubes (NTC) are being largely developed. New attenuators materials have been widely investigated for radiation shielding to apply in procedures as interventional radiology, Computed Tomography (CT) and nuclear medicine. In this work composites for radiation attenuation in radiodiagnostic imaging procedures made of inorganic material as filler, by a sol-gel method, in poly(vinylidene fluoride-tryfluorethylene) [P(VDF-TrFE] copolymers that are used as the polymeric matrix. Two different metal attenuators were used as fillers: zirconia stabilized by yttria (8% wt.) and bismuth oxide. Carbon nanotubes were added with different concentrations at the solution of attenuator metal under controlled magnetic stirring. Characterization of composites by FTIR, UV-Vis, DSC and SEM-EDS were carried out. In a previous analysis of radiation attenuation, was used an incident monochromatic X-ray beam from the RIGAKU diffractometer. In this setup, one reference measure is directly exposed to the x-rays being diffracted by single crystal of Si (111). Another measure the attenuated beam is performed with the composite sample under detector. The functionalization of the carbon nanotube of multiple walls (MWNCT) in the in the P(VDF-TrFE) was evaluated. The samples present a good dispersion of the attenuator metal into presence at methacrylic acid. The cheap tube presented better dispersion in the polymer matrix than the 3100 nanotubes. Bismuth oxidation composites showed a better attenuation factor compared to Zirconia stabilized by yttria composites. (author)

  9. Shielding from cosmic radiation for interplanetary missions Active and passive methods

    CERN Document Server

    Spillantini, P; Durante, M; Müller-Mellin, R; Reitz, G; Rossi, L; Shurshakov, V; Sorbi, M

    2007-01-01

    Shielding is arguably the main countermeasure for the exposure to cosmic radiation during interplanetary exploratory missions. However, shielding of cosmic rays, both of galactic or solar origin, is problematic, because of the high energy of the charged particles involved and the nuclear fragmentation occurring in shielding materials. Although computer codes can predict the shield performance in space, there is a lack of biological and physical measurements to benchmark the codes. An attractive alternative to passive, bulk material shielding is the use of electromagnetic fields to deflect the charged particles from the spacecraft target. Active shielding concepts based on electrostatic fields, plasma, or magnetic fields have been proposed in the past years, and should be revised based on recent technological improvements. To address these issues, the European Space Agency (ESA) established a Topical Team (TT) in 2002 including European experts in the field of space radiation shielding and superconducting magn...

  10. Numerical Models for the Study of Electromagnetic Shielding

    Directory of Open Access Journals (Sweden)

    POPA Monica

    2012-10-01

    Full Text Available The paper presents 2D and 3D models for the study of electromagnetic shielding of a coil. The magnetic fields are computed for defining the shielding effectiveness. Parametrized numerical studies were performed in order to established the influence of shield thickness and height on magnetic field in certain points located in the exterior of coil – shield setup and on induced power within the shield.

  11. AB INITIO STUDY, INVESTIGATION OF NMR SHIELDING ...

    African Journals Online (AJOL)

    Preferred Customer

    Ab initio study, investigation of NMR shielding tensors, NBO and vibrational frequency. Bull. Chem. Soc. Ethiop. 2010, 24(2). 231. Gas phase results. In order to study mechanism of the reactions, structure corresponding to reactants, transition states and products were optimized in level of theory. Figure 1 shows the ...

  12. Radiation shielding analysis for 50 kVp x-ray intra-operative radiotherapy (IORT) device using MCNPX code

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zhao Jun; Yeom, Yeon Soo; Kim, Chan Hyeong [Hanyang University, Seoul (Korea, Republic of)

    2014-04-15

    The present study performed Monte Carlo simulations for the 50 kVp X-ray intra-operative radiotherapy (IORT) device for detailed radiation shielding analysis. The INTRABEAM system (Carl Zeiss Surgical, Oberkochen, Germany) is a compact 50 kVp X-ray device used for intra-operative radiotherapy (IORT) especially for breast cancer. The IORT system has the advantages of very rapid dose gradient and, due to the on/off switching system, no risk of contamination when compared to nuclear medicine procedure. In contrast to megavoltage radiotherapy system requiring a dedicated shielding bunker, the IORT system is generally performed in standard operating theatres and simply uses a thin shield on the treated area and lead screens for protection of staffs who stay in the theatre during treatment. For detailed radiation shielding analysis of the IORT system, the present study performed Monte Carlo simulations with the MCNPX code to calculate dose rate distributions and investigated effects of several shielding components generally considered in this system. It was shown that shielding with flat cover and lead screen generally used is sufficient to reduce occupational doses to a negligible level. The analysis results of this study can be referred to estimate shielding requirements for other IORT systems.

  13. EVALUATION OF BRACHYTHERAPY FACILITY SHIELDING STATUS IN KOREA OBTAINED FROM RADIATION SAFETY REPORTS

    Directory of Open Access Journals (Sweden)

    MI HYUN KEUM

    2013-10-01

    Full Text Available Thirty-eight radiation safety reports for brachytherapy equipment were evaluated to determine the current status of brachytherapy units in Korea and to assess how radiation oncology departments in Korea complete radiation safety reports. The following data was collected: radiation safety report publication year, brachytherapy unit manufacturer, type and activity of the source that was used, affiliation of the drafter, exposure rate constant, the treatment time used to calculate workload and the HVL values used to calculate shielding design goal values. A significant number of the reports (47.4% included the personal information of the drafter. The treatment time estimates varied widely from 12 to 2,400 min/week. There was acceptable variation in the exposure rate constant values (ranging between 0.469 and 0.592 (R-m2/Ci·hr, as well as in the HVLs of concrete, steel and lead for Iridium-192 sources that were used to calculate shielding design goal values. There is a need for standard guidelines for completing radiation safety reports that realistically reflect the current clinical situation of radiation oncology departments in Korea. The present study may be useful for formulating these guidelines.

  14. Reduction of operator radiation dose by a pelvic lead shield during cardiac catheterization by radial access: comparison with femoral access.

    Science.gov (United States)

    Lange, Helmut W; von Boetticher, Heiner

    2012-04-01

    This study sought to determine the efficacy of patient pelvic lead shielding for the reduction of operator radiation exposure during cardiac catheterization via the radial access in comparison with the femoral access. Cardiac catheterization via the radial access is associated with significantly increased radiation dose to the patient and the operator. Improvements in radiation protection are needed to minimize this drawback. Pelvic lead shielding has the potential to reduce operator radiation dose. We randomly assigned 210 patients undergoing elective coronary angiography by the same operator to a radial and femoral access with and without pelvic lead shielding of the patient. Operator radiation dose was measured by a radiation dosimeter attached to the outside breast pocket of the lead apron. For radial access, operator dose decreased from 20.9 ± 13.8 μSv to 9.0 ± 5.4 μSv, p lead shielding. For femoral access, it decreased from 15.3 ± 10.4 μSv to 2.9 ± 2.7 μSv, p lead shielding significantly decreased the dose-area product-normalized operator dose (operator dose divided by the dose-area product) by the same amount for radial and femoral access (0.94 ± 0.28 to 0.39 ± 0.19 μSv × Gy(-1) × cm(-2) and 0.70 ± 0.26 to 0.16 ± 0.13 μSv × Gy(-1) × cm(-2), respectively). Pelvic lead shielding is highly effective in reducing operator radiation exposure for radial as well as femoral procedures. However, despite its use, radial access remains associated with a higher operator radiation dose. Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  15. Determination of minimum effective height of transparent radiation face shielding for fluoroscopy.

    Science.gov (United States)

    Prater, Scott; Rees, Chet R; Bruner, Angela; Savage, Clare

    2011-11-01

    During interventional procedures, the vast majority of scatter radiation originates from the patient and table and travels in all directions in straight lines. Because the operator's head is much higher than the patient and at an angle upward and to the side of the patient (not directly above), the scatter received by the operator's head is projected in an upward angle. Thus a face shield could potentially be lower than the object it is shielding, e.g., below the eyes. This principle may be used as an advantage to design the lowest shield that effectively protects the head while providing optimum vision, appearance, acoustics, low weight, and sense of openness. A flat acrylic plate shield, 0.5 mm Pb equivalence, was suspended vertically in front of a 451P dosimeter. A phantom patient created scatter in an interventional suite while the dosimeter was placed at the level of the crowns of different operators' heads. Many different configurations were tested to determine which ones would provide effective shielding. The results confirmed that the top of the shield may reside several centimeters below the vertical height of the dosimeter (operator's crown), allowing line of sight to monitor above the shield, and still provide effective shielding equivalent to when the dosimeter is positioned directly behind the center of the shield. The image receptor functioned as an effective shield against scatter. Factors increasing the minimum height of effective shielding included shorter operator, opposite oblique projection of image receptor, and shield closer to the face (in horizontal direction).

  16. Bibliography, subject index, and author index of the literature examined by the Radiation Shielding Information Center (Reactor and Weapons Radiation Shielding). [1973--1976

    Energy Technology Data Exchange (ETDEWEB)

    1978-01-01

    An indexed bibliography is presented of literature selected by the Radiation Shielding Information Center since the previous volume was published in 1974 in the area of radiation transport and shielding against radiation from nuclear reactors, x-ray machines, radioisotopes, nuclear weapons (including fallout), and low-energy accelerators (e.g., neutron generators). In addition to lists of literature titles by subject categories (accessions 3501-4950), author and keyword indexes are given. Most of the literature selected for Vol. V was published in the years 1973 to 1976.

  17. Bibliography, subject index, and author index of the literature examined by the radiation shielding information center. Volume 6. Reactor and weapons radiation shielding

    Energy Technology Data Exchange (ETDEWEB)

    1980-05-01

    An indexed bibliography is presented of literature selected by the Radiation Shielding Information Center since the previous volume was published in 1978 in the area of radiation transport and shielding against radiation from nuclear reactors, x-ray machines, radioisotopes, nuclear weapons (including fallout), and low energy accelerators (e.g., neutron generators). The bibliography was typeset from data processed by computer from magnetic tape files. In addition to lists of literature titles by subject categories (accessions 4951-6200), an author index is given.

  18. A study on the calculation of the shielding wall thickness in medical linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Yeon [Dept. of Radiation Oncology, Dongnam Ins. of Radiological and Medical Science, Busan (Korea, Republic of); Park, Eun Tae [Dept. of Radiation Oncology, Inje University Busan Paik Hospital, Busan (Korea, Republic of); Kim, Jung Hoon [Dept. of Radiological science, college of health sciences, Catholic University of Pusan, Busan (Korea, Republic of)

    2017-06-15

    The purpose of this study is to calculate the thickness of shielding for concrete which is mainly used for radiation shielding and study of the walls constructed to shield medical linear accelerator. The optimal shielding thickness was calculated using MCNPX(Ver.2.5.0) for 10 MV of photon beam energy generated by linear accelerator. As a result, the TVL for photon shielding was formed at 50⁓100 cm for pure concrete and concrete with Boron+polyethylene at 80⁓100 cm. The neutron shielding was calculated 100⁓140 cm for pure concrete and concrete with Boron+polyethylene at 90⁓100 cm. Based on this study, the concrete is considered to be most efficient method of using steel plates and adding Boron+polyethylene th the concrete.

  19. Coupled Radiation Transport/Thermal Analysis of the Radiation Shield for a Space Nuclear Reactor.

    Science.gov (United States)

    1985-07-01

    thermal analysis of radiation shield are those of Beiriger (1968) and Thompson and Schwab (1969). Belriger (1968) conducted a thermal analysis of Pb-W...regarding how the temperature values were generated were not reported. Thompson and Schwab (1969) examined the accuracy of several neu- tronic models in...Publishing Company, Inc., 1984. Bathe, Klaus -Jurgen, Finite Element Procedures in Engineering Analy- sis, New Jersey: Prentice Hall, Inc., 1982. deckurts, K.H

  20. Utilization of recycled cathode ray tubes glass in cement mortar for X-ray radiation-shielding applications.

    Science.gov (United States)

    Ling, Tung-Chai; Poon, Chi-Sun; Lam, Wai-Shung; Chan, Tai-Po; Fung, Karl Ka-Lok

    2012-01-15

    Recycled glass derived from cathode ray tubes (CRT) glass with a specific gravity of approximately 3.0 g/cm(3) can be potentially suitable to be used as fine aggregate for preparing cement mortars for X-ray radiation-shielding applications. In this work, the effects of using crushed glass derived from crushed CRT funnel glass (both acid washed and unwashed) and crushed ordinary beverage container glass at different replacement levels (0%, 25%, 50%, 75% and 100% by volume) of sand on the mechanical properties (strength and density) and radiation-shielding performance of the cement-sand mortars were studied. The results show that all the prepared mortars had compressive strength values greater than 30 MPa which are suitable for most building applications based on ASTM C 270. The density and shielding performance of the mortar prepared with ordinary crushed (lead-free) glass was similar to the control mortar. However, a significant enhancement of radiation-shielding was achieved when the CRT glasses were used due to the presence of lead in the glass. In addition, the radiation shielding contribution of CRT glasses was more pronounced when the mortar was subject to a higher level of X-ray energy. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. A randomized study comparing the use of a pelvic lead shield during trans-radial interventions: Threefold decrease in radiation to the operator but double exposure to the patient.

    Science.gov (United States)

    Musallam, Anees; Volis, Ina; Dadaev, Svetlana; Abergel, Eitan; Soni, Amit; Yalonetsky, Sergey; Kerner, Arthur; Roguin, Ariel

    2015-06-01

    To determine the efficacy of a 0.5-mm lead apron across the patient's abdomen in addition to standard operator protection for the reduction of scatter radiation on operator and patient radiation exposure Cardiac angiography using the radial access compared to the femoral approach is associated with reduced complication rate and improved patient comfort but has significantly increased radiation dose. Improvements in radiation protection are needed We randomly assigned 332 patients undergoing coronary angiography to a group with pelvic lead shielding and a group with standard protection. In each procedure, eight digital dosimeters were used to measure operator radiation dose [under the lead apron, outside the thyroid shield, and at the left side of the head], patient dose at the level of the umbilicus [above and beneath the lead apron], and two on the acrylic shielding and one on the image receptor to measure scattered radiation Both groups were similar in BMI, procedures performed, and number of sequences. Usage of lead shielding statistically significantly reduced the radiation dose of the operator at all three sites measured: under lead apron [all in µSv]: 0.53 ± 1.4 vs. 0.17 ± 0.6, on thyroid collar 5.9 ± 7.7 vs. 2.9 ± 3.4, and left side of head 3.3 ± 3.4 vs. 2.1 ± 2.2, Plead shield during radial angiography reduced the operator radiation exposure at multiple measurement sites. However there was an increased exposure to the patient. This balance should be further investigated before the widespread adoption of this method. . © 2015 Wiley Periodicals, Inc.

  2. Radiation dose reduction at a price: the effectiveness of a male gonadal shield during helical CT scans

    Directory of Open Access Journals (Sweden)

    Erdi Yusuf E

    2007-03-01

    Full Text Available Abstract Background It is estimated that 60 million computed tomography (CT scans were performed during 2006, with approximately 11% of those performed on children age 0–15 years. Various types of gonadal shielding have been evaluated for reducing exposure to the gonads. The purpose of this study was to quantify the radiation dose reduction to the gonads and its effect on image quality when a wrap-around male pediatric gonad shield was used during CT scanning. This information is obtained to assist the attending radiologist in the decision to utilize such male gonadal shields in pediatric imaging practice. Methods The dose reduction to the gonads was measured for both direct radiation and for indirect scattered radiation from the abdomen. A 6 cm3 ion chamber (Model 10X5-6, Radcal Corporation, Monrovia, CA was placed on a Humanoid real bone pelvic phantom at a position of the male gonads. When exposure measurements with shielding were made, a 1 mm lead wrap-around gonadal shield was placed around the ion chamber sensitive volume. Results The use of the shields reduced scatter dose to the gonads by a factor of about 2 with no appreciable loss of image quality. The shields reduced the direct beam dose by a factor of about 35 at the expense of extremely poor CT image quality due to severe streak artifacts. Conclusion Images in the direct exposure case are not useful due to these severe artifacts and the difficulties in positioning these shields on patients in the scatter exposure case may not be warranted by the small absolute reduction in scatter dose unless it is expected that the patient will be subjected to numerous future CT scans.

  3. Multilayer Polymeric Shielding to Protect Humans from Galactic Cosmic Radiation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In Sub-topic X4.01, NASA has identified a need for advanced radiation-shielding materials and structures to protect humans from the hazards of galactic cosmic...

  4. Modeling, Testing and Deploying a Multifunctional Radiation Shielding / Hydrogen Storage Unit Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project addresses two vital problems for long-term space travel activities: radiation shielding and hydrogen storage for power and propulsion. While both...

  5. Multifunctional Carbon Nanotube/Polyethylene Complex Composites for Space Radiation Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Polyethylene (PE), due to its high hydrogen content relative to its weight, has been identified by NASA as a promising radiation shielding material against galactic...

  6. Innovative, Lightweight Thoraeus RubberTM for MMOD and Space Radiation Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NanoSonic offers an innovative manufacturing process to yield ultra-lightweight radiation shielding nanocomposites by exploiting the concept of the Thoraeus filter...

  7. News from the Library: Facilitating access to a program for radiation shielding - the Library can help

    CERN Multimedia

    CERN Library

    2013-01-01

    MicroShield® is a comprehensive photon/gamma ray shielding and dose assessment programme. It is widely used for designing shields, estimating source strength from radiation measurements, minimising exposure to people, and teaching shielding principles.   Integrated tools allow the graphing of results, material and source file creation, source inference with decay (dose-to-Bq calculations accounting for decay and daughter buildup), the projection of exposure rate versus time as a result of decay, access to material and nuclide data, and decay heat calculations. The latest version is able to export results using Microsoft Office (formatted and colour-coded for readability). Sixteen geometries accommodate offset dose points and as many as ten standard shields plus source self-shielding and cylinder cladding are available. The library data (radionuclides, attenuation, build-up and dose conversion) reflect standard data from ICRP 38 and 107* as well as ANSI/ANS standards and RSICC publicat...

  8. Scatter radiation breast exposure during head CT: impact of scanning conditions and anthropometric parameters on shielded and unshielded breast dose

    Energy Technology Data Exchange (ETDEWEB)

    Klasic, B. [Hospital for pulmonary diseases, Zagreb (Croatia); Knezevic, Z.; Vekic, B. [Rudjer Boskovic Institute, Zagreb (Croatia); Brnic, Z.; Novacic, K. [Merkur Univ. Hospital, Zagreb (Croatia)

    2006-07-01

    Constantly increasing clinical requests for CT scanning of the head on our facility continue to raise concern regarding radiation exposure of patients, especially radiosensitive tissues positioned close to the scanning plane. The aim of our prospective study was to estimate scatter radiation doses to the breast from routine head CT scans, both with and without use of lead shielding, and to establish influence of various technical and anthropometric factors on doses using statistical data analysis. In 85 patient referred to head CT for objective medical reasons, one breast was covered with lead apron during CT scanning. Radiation doses were measured at skin of both breasts and over the apron simultaneously, by the use of thermo luminescent dosimeters. The doses showed a mean reduction by 37% due to lead shielding. After we statistically analyzed our data, we observed significant correlation between under-the-shield dose and values of technical parameters. We used multiple linear regression model to describe the relationships of doses to unshielded and shielded breast respectively, with anthropometric and technical factors. Our study proved lead shielding of the breast to be effective, easy to use and leading to a significant reduction in scatter dose. (author)

  9. Shielding Effectiveness of Laminated Shields

    Directory of Open Access Journals (Sweden)

    B. P. Rao

    2008-12-01

    Full Text Available Shielding prevents coupling of undesired radiated electromagnetic energy into equipment otherwise susceptible to it. In view of this, some studies on shielding effectiveness of laminated shields with conductors and conductive polymers using plane-wave theory are carried out in this paper. The plane wave shielding effectiveness of new combination of these materials is evaluated as a function of frequency and thickness of material. Conductivity of the polymers, measured in previous investigations by the cavity perturbation technique, is used to compute the overall reflection and transmission coefficients of single and multiple layers of the polymers. With recent advances in synthesizing stable highly conductive polymers these lightweight mechanically strong materials appear to be viable alternatives to metals for EM1 shielding.

  10. Radiation Shielding Utilizing A High Temperature Superconducting Magnet Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project aims to leverage near-term high-temperature superconducting technologies to assess applicability of magnetic shielding for protecting against exposure...

  11. Hawking radiation screening and Penrose process shielding in the Kerr black hole

    Energy Technology Data Exchange (ETDEWEB)

    Mc Caughey, Eamon [Dublin Institute of Technology, School of Mathematical Sciences, Dublin 8 (Ireland)

    2016-04-15

    The radial motion of massive particles in the equatorial plane of a Kerr black hole is considered. Screening of the Hawking radiation and shielding of the Penrose process are examined (both inside and outside the ergosphere) and their effect on the evaporation of the black hole is studied. In particular, the locus and width of a classically forbidden region and their dependence on the particle's angular momentum and energy is analysed. Tunneling of particles between the boundaries of this region is considered and the transmission coefficient determined. (orig.)

  12. Radiation Exposure Among Scrub Technologists and Nurse Circulators During Cardiac Catheterization: The Impact of Accessory Lead Shields.

    Science.gov (United States)

    Madder, Ryan D; LaCombe, Andrew; VanOosterhout, Stacie; Mulder, Abbey; Elmore, Matthew; Parker, Jessica L; Jacoby, Mark E; Wohns, David

    2017-10-25

    This study was performed to determine if the use of an accessory lead shield is associated with a reduction in radiation exposure among staff members during cardiac catheterization. Accessory lead shields that protect physicians from scatter radiation are standard in many catheterization laboratories, yet similar shielding for staff members is not commonplace. Real-time radiation exposure data were prospectively collected among nurses and technologists during 764 consecutive catheterizations. The study had 2 phases: in phase I (n = 401), standard radiation protection measures were used, and in phase II (n = 363), standard radiation protection measures were combined with an accessory lead shield placed between the staff member and patient. Radiation exposure was reported as the effective dose normalized to dose-area product (EDAP). Use of an accessory lead shield in phase II was associated with a 62.5% lower EDAP per case among technologists (phase I: 2.4 [4.3] μSv/[mGy × cm2] × 10-5; phase II: 0.9 [2.8] μSv/[mGy × cm2] × 10-5; p nurses (phase I: 1.1 [3.1] μSv/[mGy × cm2] × 10-5; phase II: 0.4 [1.8] μSv/[mGy × cm2] × 10-5; p nurses (36.4% reduction; 95% confidence interval: 19.7% to 49.6%; p nurses and technologists. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  13. Computational Design of Epoxy/ Boron Carbide Nanocomposites for Radiation Shielding Applications

    Science.gov (United States)

    Bejagam, Karteek; Galehdari, Nasim; Espinosa, Ingrid; Deshmukh, Sanket A.; Kelkar, Ajit D.

    An individual working in industries that include nuclear power plants, healthcare industry, and aerospace are knowingly or unknowingly exposed to radiations of different energies. Exposure to high-energy radiations such as α/ β particle emissions or gamma ray electromagnetic radiations enhances the health risks that can lead to carcinogenesis, cardiac problems, cataracts, and other acute radiation syndromes. The best possible solution to protect one from the exposure to radiations is shielding. In the present study, we have developed a new algorithm to generate a range of different structures of Diglycidyl Ether of Bisphenol F (EPON 862) and curing agent Diethylene Toluene Diamine (DETDA) resins with varying degrees of crosslinking. 3, 5, and 10 weight percent boron carbide was employed as filling materials to study its influence on the thermal and mechanical properties of composite. We further conduct the reactive molecular dynamics (RMD) simulations to investigate the effect of radiation exposure on the structural, physical, and mechanical properties of these Epoxy/Boron Carbide nanocomposites. Where possible the simulation results were compared with the experimental data.

  14. Antithermal shield for rockets with heat evacuation by infrared radiation reflection

    Directory of Open Access Journals (Sweden)

    Ioan RUSU

    2010-12-01

    Full Text Available At high speed, the friction between the air mass and the rocket surface causes a localheating of over 1000 Celsius degrees. For the heat protection of the rocket, on its outside surfacethermal shields are installed.Studying the Coanda effect, the fluid flow on solids surface, respectively, the author Ioan Rusuhas discovered by simply researches that the Coanda effect could be /extended also to the fluid flowon discontinuous solids, namely, on solids provided with orifices. This phenomenon was named by theauthor, the expanded Coanda effect. Starting with this discovery, the author has invented a thermalshield, registered at The State Office for inventions and Trademarks OSIM, deposit F 2010 0153This thermal shield:- is built as a covering rocket sheet with many orifices installed with a minimum space fromthe rocket body- takes over the heat fluid generated by the frontal part of the rocket and avoids the directcontact between the heat fluid and the rocket body- ensures the evacuation of the infrared radiation, generated by the heat fluid flowing overthe shield because of the extended Coanda effect by reflection from the rocket bodysurface.

  15. A DGTD Scheme for Modeling the Radiated Emission From DUTs in Shielding Enclosures Using Near Electric Field Only

    KAUST Repository

    Li, Ping

    2016-01-13

    To meet the electromagnetic interference regulation, the radiated emission from device under test such as electronic devices must be carefully manipulated and accurately characterized. Instead of resorting to the direct far-field measurement, in this paper, a novel approach is proposed to model the radiated emission from electronic devices placed in shielding enclosures by using the near electric field only. Based on the Schelkkunoff’s equivalence principle and Raleigh–Carson reciprocity theorem, only the tangential components of the electric field over the ventilation slots and apertures of the shielding enclosure are sufficient to obtain the radiated emissions outside the shielding box if the inside of the shielding enclosure was filled with perfectly electric conductor (PEC). In order to efficiently model wideband emission, the time-domain sampling scheme is employed. Due to the lack of analytical Green’s function for arbitrary PEC boxes, the radiated emission must be obtained via the full-wave numerical methods by considering the total radiated emission as the superposition between the direct radiation from the equivalent magnetic currents in free space and the scattered field generated by the PEC shielding box. In this study, the state-of-the-art discontinuous Galerkin time-domain (DGTD) method is utilized, which has the flexibility to model irregular geometries, keep high-order accuracy, and more importantly involves only local operations. For open-region problems, a hybridized DGTD and time-domain boundary integration method applied to rigorously truncate the computational domain. To validate the proposed approach, several representative examples are presented and compared with both analytical and numerical results.

  16. AA, radiation shielding curtain along the target area

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    At the far left is the beam tube for the high-intensity proton beam from the 26 GeV PS. The tube ends in a thin window and the proton beam continues in air through a hole in the shielding blocks (see also 8010308), behind which the target (see 7905091, 7905094)was located. After the target followed the magnetic horn, focusing the antiprotons, and the first part of the injection line with a proton dump. The antiprotons, deflected by a magnet, left the target area through another shielding wall, to make their way to the AA ring. Laterally, this sequence of components was shielded with movable, suspended, concrete blocks: the "curtain". Balasz Szeless, who had constructed it, is standing at its side.

  17. TFTR radiation contour and shielding efficiency measurements during D-D operations

    Energy Technology Data Exchange (ETDEWEB)

    Kugel, H.W.; Ascione, G.; Elwood, S.; Gilbert, J.; Hwang, D.; Lewis, M.; Levine, J.; Ku, L.P.; Rule, K. [Princeton Plasma Physics Lab., NJ (United States); Hajnal, F. [Department of Energy, New York, NY (United States)] [and others

    1994-11-01

    Extensive neutron and gamma radiation contour, shielding efficiency, and spectral measurements were performed during high power TFTR D-D operations at the tokamak Test Cell inner walls, ceiling, roof, and outer walls, in nearby control rooms, work areas, and personnel pathways, outdoors along the site fence at 125 m, and out to the nearest property lines at 180 m. The results confirmed that the efficiency of the basic radiation shielding was sufficient to allow the TFTR D-T experimental plan, and provide empirical guidance for simulating the radiation fields of future fusion reactors.

  18. Resistivity, ESR, and Radiation Shielding Properties of the Volcanic Rock Materials

    Directory of Open Access Journals (Sweden)

    Çiğdem Nuhoğlu

    2014-01-01

    Full Text Available Pumices have been used in cement, concrete, brick, and ceramic industries as an additive and aggregate material. It will be important to study pumice types by using a different tool as EPR which is a new technique for related material to be used for industrial aims. Electron spin resonance (ESR spectra of the pumice types were taken by EMX-type spectrometer. Also, the current-voltage (I-V and surface resistivity probe stand of the thin films was studied using a four-point probe measurements. The relationship between radiation shielding properties of the pumice samples and their surface resistivity, chemical, and electrokinetic properties was evaluated using simple regression analysis. Simple regression analysis indicated a strong correlation between surface resistivity and density and SiO2, Fe2O3, CaO, MgO, and TiO2 content of pumice samples in this study. It is found that a correlation between determined g-factor by EPR spectroscopy and radiation shielding is established for pumice samples.

  19. Influence of the Radiation Shield on the Temperature of Rails Rolled in the Reversing Mill

    Directory of Open Access Journals (Sweden)

    Gołdasz A.

    2015-04-01

    Full Text Available The paper presents a mathematical model of heat transfer during cooling of hot-rolled rails in the reversing mill. The influence of the radiation shield on the temperature of rolled rails has been analyzed. The heat transfer model for cooling a strip covered by the thermal shield has been presented. The two types of shields build of steel and aluminum sheets separated with insulating layer have been studded. Calculations have been performed with self developed software which utilizes the finite element method.

  20. Radiation production and absorption in human spacecraft shielding systems under high charge and energy Galactic Cosmic Rays: Material medium, shielding depth, and byproduct aspects

    Science.gov (United States)

    Barthel, Joseph; Sarigul-Klijn, Nesrin

    2018-03-01

    Deep space missions such as the planned 2025 mission to asteroids require spacecraft shields to protect electronics and humans from adverse effects caused by the space radiation environment, primarily Galactic Cosmic Rays. This paper first reviews the theory on how these rays of charged particles interact with matter, and then presents a simulation for a 500 day Mars flyby mission using a deterministic based computer code. High density polyethylene and aluminum shielding materials at a solar minimum are considered. Plots of effective dose with varying shield depth, charged particle flux, and dose in silicon and human tissue behind shielding are presented.

  1. Geant4 calculations for space radiation shielding material Al2O3

    Directory of Open Access Journals (Sweden)

    Capali Veli

    2015-01-01

    Full Text Available Aluminium Oxide, Al2O3 is the most widely used material in the engineering applications. It is significant aluminium metal, because of its hardness and as a refractory material owing to its high melting point. This material has several engineering applications in diverse fields such as, ballistic armour systems, wear components, electrical and electronic substrates, automotive parts, components for electric industry and aero-engine. As well, it is used as a dosimeter for radiation protection and therapy applications for its optically stimulated luminescence properties. In this study, stopping powers and penetrating distances have been calculated for the alpha, proton, electron and gamma particles in space radiation shielding material Al2O3 for incident energies 1 keV – 1 GeV using GEANT4 calculation code.

  2. Radiation Exposure Analyses Supporting the Development of Solar Particle Event Shielding Technologies

    Science.gov (United States)

    Walker, Steven A.; Clowdsley, Martha S.; Abston, H. Lee; Simon, Hatthew A.; Gallegos, Adam M.

    2013-01-01

    NASA has plans for long duration missions beyond low Earth orbit (LEO). Outside of LEO, large solar particle events (SPEs), which occur sporadically, can deliver a very large dose in a short amount of time. The relatively low proton energies make SPE shielding practical, and the possibility of the occurrence of a large event drives the need for SPE shielding for all deep space missions. The Advanced Exploration Systems (AES) RadWorks Storm Shelter Team was charged with developing minimal mass SPE storm shelter concepts for missions beyond LEO. The concepts developed included "wearable" shields, shelters that could be deployed at the onset of an event, and augmentations to the crew quarters. The radiation transport codes, human body models, and vehicle geometry tools contained in the On-Line Tool for the Assessment of Radiation In Space (OLTARIS) were used to evaluate the protection provided by each concept within a realistic space habitat and provide the concept designers with shield thickness requirements. Several different SPE models were utilized to examine the dependence of the shield requirements on the event spectrum. This paper describes the radiation analysis methods and the results of these analyses for several of the shielding concepts.

  3. Experimental Shielding Evaluation of the Radiation Protection Provided by Residential Structures

    Science.gov (United States)

    Dickson, Elijah D.

    The human health and environmental effects following a postulated accidental release of radioactive material to the environment has been a public and regulatory concern since the early development of nuclear technology and researched extensively to better understand the potential risks for accident mitigation and emergency planning purposes. The objective of this investigation is to research and develop the technical basis for contemporary building shielding factors for the U.S. housing stock. Building shielding factors quantify the protection a certain building-type provides from ionizing radiation. Much of the current data used to determine the quality of shielding around nuclear facilities and urban environments is based on simplistic point-kernel calculations for 1950's era suburbia and is no longer applicable to the densely populated urban environments seen today. To analyze a building's radiation shielding properties, the ideal approach would be to subject a variety of building-types to various radioactive materials and measure the radiation levels in and around the building. While this is not entirely practicable, this research uniquely analyzes the shielding effectiveness of a variety of likely U.S. residential buildings from a realistic source term in a laboratory setting. Results produced in the investigation provide a comparison between theory and experiment behind building shielding factor methodology by applying laboratory measurements to detailed computational models. These models are used to develop a series of validated building shielding factors for generic residential housing units using the computational code MCNP5. For these building shielding factors to be useful in radiologic consequence assessments and emergency response planning, two types of shielding factors have been developed for; (1) the shielding effectiveness of each structure within a semi-infinite cloud of radioactive material, and (2) the shielding effectiveness of each structure

  4. Radiation Protection of New Lightweight Electromagnetic Interference Shielding Materials Determined

    Science.gov (United States)

    1996-01-01

    Weight savings as high as 80 percent could be achieved by simply switching from aluminum electromagnetic interference (EMI) shielding covers for spacecraft power systems to EMI covers made from intercalated graphite fiber composites. Because EMI covers typically make up about one-fifth of the power system mass, this change would decrease the mass of a spacecraft power system by more than 15 percent. Intercalated graphite fibers are made by diffusing guest atoms or molecules, such as bromine, between the carbon planes of the graphite fibers. The resulting bromine-intercalated fibers have mechanical and thermal properties nearly identical to pristine graphite fibers, but their resistivity is lower by a factor of 5, giving them better electrical conductivity than stainless steel and making these composites suitable for EMI shielding.

  5. Study on the effectiveness of QPS electronics shielding

    CERN Document Server

    Versaci, R

    2012-01-01

    About 30% of the 2011 LHC downtime is due to failures of the Quench Protection System (QPS) induced by the radiation affecting the electronics located below the LHC main dipoles (MB). In the view of LHC technical stop foreseen for December 2011, we have investigated, by means of FLUKA simulations, the efficiency of an iron shielding to reduce the radiation affecting the QPS electronics. These are situated in the Dispersion Suppressors where the use of radiation resistant hardware is not immediately possible.

  6. Analytical theory of coherent synchrotron radiation wakefield of short bunches shielded by conducting parallel plates

    Energy Technology Data Exchange (ETDEWEB)

    Stupakov, Gennady; Zhou, Demin

    2016-04-21

    We develop a general model of coherent synchrotron radiation (CSR) impedance with shielding provided by two parallel conducting plates. This model allows us to easily reproduce all previously known analytical CSR wakes and to expand the analysis to situations not explored before. It reduces calculations of the impedance to taking integrals along the trajectory of the beam. New analytical results are derived for the radiation impedance with shielding for the following orbits: a kink, a bending magnet, a wiggler of finite length, and an infinitely long wiggler. All our formulas are benchmarked against numerical simulations with the CSRZ computer code.

  7. Investigation of gold as a material for thermal radiation shielding

    Science.gov (United States)

    Munshi, Amit Harenkumar

    CdS/CdTe thin film solar cells technology is one of the fastest growing carbon neutral energy sources in the world today. Manufacturing of CdS/CdTe solar modules is carried out at temperature in the range of 620350°C under a vacuum of 40 millitorr using a Heated Pocket Deposition (HPD) system in the materials engineering laboratory. Since this system operates in vacuum, majority of the heat loss is due to thermal radiation. The concept here is to conserve the heat by reflecting the infrared radiation back into the deposition system thus increasing the thermal efficiency. Various metals may be used but calculations show that using a Gold thin film mirror can effectively reflect almost 97% of the incident radiation, thus conserving energy required for the manufacturing process. However, a phenomenon called thermal grooving or island formation inhibits its use. Thermal grooving occurs when the stress concentration at the grain boundaries causes grain separation. This phenomenon is observed in thin gold films that are exposed to a temperature in excess of 350°C for over 3 to 5 hours. In this study, these films are exposed to temperature upto 620350°C for cycles as long as 200 hours. The goal of this research is to explore the solutions for elimination of the phenomenon of thermal grooving and thus extract maximum life out of these thin gold films for conservation of heat. After carefully exploring literature on past research and conducting experiments it was found that within the range of the films that were tested, a 2000 A350° film with a 150 A350° of Indium underlay showed the best performance after thermal annealing and testing.

  8. UHMW-PE. A shielding material with special properties influenced by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ehe, K. von der; Jaunich, M.; Wolff, D. [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

    2011-07-01

    , crystallinity growth and increased perfection in the crystal lamellae. Chain scission results in shorter polymer molecules, fewer entanglements, and consequently, increased molecular mobility. The scope of our investigation comprises an estimation of the radiation and thermal impact on the molecular and supra molecular structure of the two types of PE used for neutron shielding cask components. A further point which is worth to explore is to what extent these changes are detectable by thermo-analytical (TA) methods, such as Differential Scanning Calorimetry (DSC), Thermo Mechanical Analysis (TMA), Dynamic Mechanical Analysis (DMA) and Thermogravimetry (TG). Additionally FT-IRand solubility measurements have been performed. In our studies we focused on the UHMW-PE material GUR 4120 which was {gamma}-irradiated at RT and compared to the untreated material. (orig.)

  9. Cosmic radiation shielding properties of COLUMBUS and REMSIM multi-layer external shells

    Science.gov (United States)

    Durante, Marco; Manti, Lorenzo; Rusek, Adam; Belluco, Maurizio; Lobascio, Cesare

    The European module COLUMBUS has been recently installed on the International Space Station. Future plans for exploration involve the use of inflatable modules, such as the REMSIM concept proposed in a previous ESA funded study. We studied the radiation shielding properties of COLUMBUS and REMSIM external shell using 1 GeV/n Feor H-ions accelerated at the NASA Space Radiation Laboratory at the Brookhaven National Laboratory (Long Island, NY, USA). COLUMBUS has a 22 mm rigid multi-layer shell with Al, Nextel and Kevlar, as materials of the double bumper for meteoroids and debris protection, MLI for thermal reasons and again Al as pressure shell. Inside the module, astronauts are further protected by secondary structures, including racks, a number of electronic devices and payload equipment. This internal equipment has been simulated using Al and Kevlar, bringing the total thickness to about 15 g/cm2. REMSIM consists of a thermal multi-layer (MLI), four Nextel layers used to provide shock of the impacting micro-meteoroids, a ballistic restraint multi-layer of Kevlar used to absorb debris cloud's kinetic energy, a Kevlar structural restraint to support pressure loads incurred from inflating the module. To contain air inside the module, REMSIM adopts three layers of airtight material separated by two layers of Kevlar (air bladder). A final layer of Nomex provide protection against punctures and fire. In the flight configuration there are also spacer elements (foam) needed to guarantee correct spacing between consecutive bumper layers. These spacers were not included in the tests, making the total thickness about 1.1 cm. The internal equipment in REMSIM was not been defined, but due to its application for exploration missions it was decided to exploit water, valuable resource used for drinking, washing and technical usage, as a radiation shielding. In this test, we have included about 8 cm of water. Measured dose attenuation shows that the Columbus module reduces the

  10. Comparative analysis of the radiation shield effect in an abdominal CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seon-Chil; Kim, Young-Jae [Daegu Health College, Daegu (Korea, Republic of); Lee, Joon-Seok [Daegu Fatima Hospital, Daegu (Korea, Republic of); Dong, Kyung-Rae [Gwangju Health University, Gwangju (Korea, Republic of); Chosun University, Gwangju (Korea, Republic of); Chung, Woon-Kwan [Chosun University, Gwangju (Korea, Republic of); Lim, Chang-Seon [Konyang University, Daejeon (Korea, Republic of)

    2014-03-15

    This study measured and compared the dose on the eyeballs and the thyroid with and without the use of a shield by applying the abdominal examination protocol used in an actual examination to a 64-channel computed tomography (CT) scan. A dummy phantom manufactured from acryl was used to measure the dose to the eyeballs and the thyroid of a patient during a thoraco-abdominal CT scan. The dose was measured using three dosimeters (optically-stimulated luminescence dosimeter (OSLD), thermoluminescence dosimeter (TLD) and photoluminescence dosimeter (PLD)) attached to the surfaces of three parts (left and right eyeballs and thyroid) in a phantom with and without the use of a shield for the eyeballs and the thyroid. Two types of shields (1-mm barium shielding sheet and 1-mm tungsten shielding sheet) were used for the measurements. The goggles and the lead shield, which are normally used in clinical practice, were used to compare the shield ratios of the shields. According to the results of the measurements made by using the OSLD, the shield ratios of the barium and the tungsten sheets were in the range of 34 - 36%. The measurements made by using the TLD showed that the shield ratio of the barium sheet was 6.25% higher than that of the tungsten sheet. When the PLD was used for the measurement, the shield ratio of the barium sheet was 33.34%, which was equivalent to that of the tungsten sheet. These results confirmed that the cheap barium sheet had a better shielding effect than the expensive tungsten sheet.

  11. Effect of Bismuth Breast Shielding on Radiation Dose and Image Quality in Coronary CT Angiography

    Science.gov (United States)

    Einstein, Andrew J.; Elliston, Carl D.; Groves, Daniel W.; Cheng, Bin; Wolff, Steven D.; Pearson, Gregory D. N.; Peters, M. Robert; Johnson, Lynne L.; Bokhari, Sabahat; Johnson, Gary W.; Bhatia, Ketan; Pozniakoff, Theodore; Brenner, David J.

    2011-01-01

    Background Coronary computed tomographic angiography (CCTA) is associated with high radiation dose to the female breasts. Bismuth breast shielding offers the potential to significantly reduce dose to the breasts and nearby organs, but the magnitude of this reduction and its impact on image quality and radiation dose have not been evaluated. Methods Radiation doses from CCTA to critical organs were determined using metal-oxide-semiconductor field-effect transistors positioned in a customized anthropomorphic whole-body dosimetry verification phantom. Image noise and signal were measured in regions of interest (ROIs) including the coronary arteries. Results With bismuth shielding, breast radiation dose was reduced 46–57% depending on breast size and scanning technique, with more moderate dose reduction to the heart, lungs, and esophagus. However, shielding significantly decreased image signal (by 14.6 HU) and contrast (by 28.4 HU), modestly but significantly increased image noise in ROIs in locations of coronary arteries, and decreased contrast-to-noise ratio by 20.9%.. Conclusions While bismuth breast shielding can significantly decrease radiation dose to critical organs, it is associated with an increase in image noise, decrease in contrast-to-noise, and changes tissue attenuation characteristics in the location of the coronary arteries. PMID:22068687

  12. INFORMATION-MEASURING SYSTEM FOR EVALUATION OF ELECTROMAGNETIC RADIATION POWER LEVELS INFLUENCE TO ITS WEAKENED BY PROTECTIVE SHIELDS

    Directory of Open Access Journals (Sweden)

    O. V. Boiprav

    2013-01-01

    Full Text Available An information-measuring system and realized on the basis of its methodology used for evaluation of electromagnetic radiation power levels passing via the protective shielding construction are described. It’s proposed to use the developed methodology for the testing of electromagnetic radiation shields for anechoic chambers

  13. Fusion reactor blanket/shield design study

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.L.; Clemmer, R.G.; Harkness, S.D.

    1979-07-01

    A joint study of tokamak reactor first-wall/blanket/shield technology was conducted by Argonne National Laboratory (ANL) and McDonnell Douglas Astronautics Company (MDAC). The objectives of this program were the identification of key technological limitations for various tritium-breeding-blanket design concepts, establishment of a basis for assessment and comparison of the design features of each concept, and development of optimized blanket designs. The approach used involved a review of previously proposed blanket designs, analysis of critical technological problems and design features associated with each of the blanket concepts, and a detailed evaluation of the most tractable design concepts. Tritium-breeding-blanket concepts were evaluated according to the proposed coolant. The ANL effort concentrated on evaluation of lithium- and water-cooled blanket designs while the MDAC effort focused on helium- and molten salt-cooled designs. A joint effort was undertaken to provide a consistent set of materials property data used for analysis of all blanket concepts. Generalized nuclear analysis of the tritium breeding performance, an analysis of tritium breeding requirements, and a first-wall stress analysis were conducted as part of the study. The impact of coolant selection on the mechanical design of a tokamak reactor was evaluated. Reference blanket designs utilizing the four candidate coolants are presented.

  14. Effect of particle size on gamma radiation shielding property of gadolinium oxide dispersed epoxy resin matrix composite

    Science.gov (United States)

    Li, Ran; Gu, Yizhuo; Wang, Yidong; Yang, Zhongjia; Li, Min; Zhang, Zuoguang

    2017-03-01

    Epoxy resin matrix composites filled with dispersed micro and nano gadolinium oxide (Gd2O3) particles of different contents were fabricated in this study. The γ radiation shielding and mechanical properties of these micro and nano composites were evaluated by measuring mass attenuation coefficients at photon energies from 31 keV to 356 keV and flexural performances. Adding Gd2O3 obviously increases mass attenuation coefficients of composites, and the enhancement is stronger at low photon energy because of dominating photoelectric effect and k-edge of element gadolinium. Effect of Gd2O3 particle size on shielding property of composite was also discussed. The results show that nano-Gd2O3 composites have better ability to shield X and γ ray than micro-Gd2O3 composites, and an enhanced effect of ~28% is obtained with Gd2O3 content of around 5 wt.% at 59.5 keV. The reason is attributed to higher probability of interaction between γ-ray and nano particles. Especially, this effect is prominent in low particle concentration. For flexural property, nano-Gd2O3/epoxy composite show equivalent flexural strength and up to15% higher flexural modulus compared with micro-Gd2O3/epoxy composite. Based on these experimental results, nano-Gd2O3 reinforced epoxy composite is believed to be a promising novel radiation shielding material.

  15. 78 FR 19148 - Shielding and Radiation Protection Review Effort and Licensing Conditions for Dry Storage...

    Science.gov (United States)

    2013-03-29

    ...The U.S. Nuclear Regulatory Commission (NRC) requests public comment on Draft Spent Fuel Storage and Transportation Interim Staff Guidance No. 26A (SFST-ISG-26A), Revision 0, ``Shielding and Radiation Protection Review Effort and Licensing Conditions for 10 CFR Part 72 Applications.''

  16. Design and evaluation of an inexpensive radiation shield for monitoring surface air temperatures

    Science.gov (United States)

    Zachary A. Holden; Anna E. Klene; Robert F. Keefe; Gretchen G. Moisen

    2013-01-01

    Inexpensive temperature sensors are widely used in agricultural and forestry research. This paper describes a low-cost (~3 USD) radiation shield (radshield) designed for monitoring surface air temperatures in harsh outdoor environments. We compared the performance of the radshield paired with low-cost temperature sensors at three sites in western Montana to several...

  17. Fabrication and Installation of Radiation Shielded Spent Fuel Fusion System

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soon Dal; Park, Yang Soon; Kim, Jong Goo; Ha, Yeong Keong; Song, Kyu Seok

    2010-02-15

    Most of the generated fission gases are retained in the fuel matrix in supersaturated state, thus alter the original physicochemical properties of the fuel. And some of them are released into free volume of a fuel rod and that cause internal pressure increase of a fuel rod. Furthermore, as extending fuel burnup, the data on fission gas generation(FGG) and fission gas release(FGR) are considered very important for fuel safety investigation. Consequently, it is required to establish an experimental facility for handling of highly radioactive sample and to develop an analytical technology for measurement of retained fission gas in a spent fuel. This report describes not only on the construction of a shielded glove box which can handle highly radioactive materials but also on the modifications and instrumentations of spent fuel fusion facilities and collection apparatuses of retained fission gas

  18. Multifunctional B/C Fiber Composites for Radiation Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Components of lunar habitat and crew modules in the lunar vehicle are constantly exposed to hazardous space conditions, such as ionizing radiation, electromagnetic...

  19. Advanced Radiation Protection (ARP): Thick GCR Shield Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Advanced Radiation Project to date has focused on SEP events.  For long duration missions outside Earth’s geomagnetic field, the galactic cosmic ray...

  20. Carbon Nanotube Reinforced Polymers for Radiation Shielding Applications

    Science.gov (United States)

    Thibeault, S. (Technical Monitor); Vaidyanathan, Ranji

    2004-01-01

    This viewgraph presentation provides information on the use of Extrusion Freeform Fabrication (EEF) for the fabrication of carbon nanotubes. The presentation addresses TGA analysis, Raman spectroscopy, radiation tests, and mechanical properties of the carbon nanotubes.

  1. A study of the electromagnetic shielding mechanisms in the GHz frequency range of graphene based composite layers

    Energy Technology Data Exchange (ETDEWEB)

    Drakakis, E. [Electrical Engineering Department, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Kymakis, E. [Electrical Engineering Department, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Tzagkarakis, G.; Louloudakis, D.; Katharakis, M. [Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Kenanakis, G. [Institute of Electronic Structure & Laser (IESL), Foundation for Research and Technology (FORTH) Hellas, Heraklion (Greece); Suchea, M.; Tudose, V. [Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Chemistry Faculty, “Al.I.Cuza” University of Iasi, Iasi (Romania); Koudoumas, E., E-mail: koudoumas@staff.teicrete.gr [Electrical Engineering Department, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece); Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion (Greece)

    2017-03-15

    Highlights: • Optimum paint contents should be chosen so that homogeneous and uniform nanocomposite layers exist exhibiting effective electromagnetic shielding. • The electromagnetic shielding in the frequency range studied comes mainly from absorption and increases with frequency. • Reflection reduces with increasing frequency, the decrease rate being smaller than that of the increase in absorption. • The shielding efficiency depends on both conductivity and thickness, the first dependence being more pronounced. - Abstract: We report on the mechanisms of the electromagnetic interference shielding effect of graphene based paint like composite layers. In particular, we studied the absorption and reflection of electromagnetic radiation in the 4–20 GHz frequency of various dispersions employing different amounts of graphene nanoplatelets, polyaniline, and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), special attention given on the relative contribution of each process in the shielding effect. Moreover, the influence of the composition, the thickness and the conductivity of the composite layers on the electromagnetic shielding was also examined.

  2. Radiation Protection Effectiveness of Polymeric Based Shielding Materials at Low Earth Orbit

    Science.gov (United States)

    Badavi, Francis F.; Stewart-Sloan, Charlotte R.; Wilson, John W.; Adams, Daniel O.

    2008-01-01

    Correlations of limited ionizing radiation measurements onboard the Space Transportation System (STS; shuttle) and the International Space Station (ISS) with numerical simulations of charged particle transport through spacecraft structure have indicated that usage of hydrogen rich polymeric materials improves the radiation shielding performance of space structures as compared to the traditionally used aluminum alloys. We discuss herein the radiation shielding correlations between measurements on board STS-81 (Atlantis, 1997) using four polyethylene (PE) spheres of varying radii, and STS-89 (Endeavour, 1998) using aluminum alloy spheres; with numerical simulations of charged particle transport using the Langley Research Center (LaRC)-developed High charge (Z) and Energy TRaNsport (HZETRN) algorithm. In the simulations, the Galactic Cosmic Ray (GCR) component of the ionizing radiation environment at Low Earth Orbit (LEO) covering ions in the 1albedo neutron environment resulting from interaction of GCR ions with upper atmosphere is modeled through extrapolation of the Atmospheric Ionizing Radiation (AIR) measurements. With the validity of numerical simulations through correlation with PE and aluminum spheres measurements established, we further present results from the expansion of the simulations through the selection of high hydrogen content commercially available polymeric constituents such as PE foam core and Spectra fiber(Registered TradeMark) composite face sheet to assess their radiation shield properties as compared to generic PE.

  3. Ultra high molecular weight polyethylene as a base material for shielding cosmic radiation in aerospace applications

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Marlon A., E-mail: marlon@ieav.cta.br [Instituto de Estudos Avancados (IEAv), Sao Jose dos Campos, SP (Brazil). Divisao de Fisica Aplicada; Goncalez, Odair L. [Instituto Tecnologico de Aeronautica (PG/CTE/ITA), Sao Jose dos Campos, SP (Brazil). Programa de Pos-Graduacao em Ciencias e Tecnologias Espaciais

    2013-07-01

    Materials with high content of hydrogen have good properties of shielding against the effects of cosmic rays (CR) because are less effective than materials with high nuclear masses in the generation of secondary radiation. Beside the Aluminum, Polyethylene has been used as a reference and as a base material for composites applied in structures and in shielding of ionizing radiation for aerospace applications. Ultra high molecular weight polyethylene (UHMWPE), pure and doped 10% by mass with cadmium chloride, had its shielding properties for CR evaluated in this paper. Methodology used was based in conventional radioactive sources employed on simple geometries experiments and then computational simulation for isotropic fluxes of cosmic-ray high energy particles. Transmission experiments were performed with a3.7GBq (100 mCi){sup 241}Am-Be neutron source and a set of conventional calibration gamma radiation sources. Samples were characterized according to their gamma total attenuation coefficients from 59 to 1,408 keV, dose deposition curve for {sup 60}Co gamma-rays, fast neutron transmission coefficient, generation and self-absorption of thermal neutrons as well as their generation of internal cascades of secondary electrons and gamma-rays by nuclear interactions of fast neutrons with shielding material. Main effects of the additive in the polyethylene base were the most effective removal of gamma radiation and of secondary electrons with energies below 200 keV, the reduction of the albedo as well as the thermal neutrons transmission. Dose reduction due to primary CR were not significant, since the largest contribution to the doses due to high energy ionizing particles transmitted and, also, due to secondary radiation with energy above 1 MeV produced in shielding. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Tulej, M., E-mail: marek.tulej@space.unibe.ch [Space Research and Planetary Sciences, Physics Institute, University of Bern, CH-3012 Bern (Switzerland); Meyer, S.; Lüthi, M.; Lasi, D.; Galli, A.; Piazza, D. [Space Research and Planetary Sciences, Physics Institute, University of Bern, CH-3012 Bern (Switzerland); Desorgher, L.; Reggiani, D.; Hajdas, W. [Laboratory of Particle Physics, Paul Scherrer Institute, CH-5232, Villigen (Switzerland); Karlsson, S.; Kalla, L. [Swedish Institute of Space Physics, Space Kampus 1, Kiruna (Sweden); Wurz, P. [Space Research and Planetary Sciences, Physics Institute, University of Bern, CH-3012 Bern (Switzerland)

    2016-09-15

    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{sup −}, μ{sup −} and π{sup −} 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{sup −} 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

  5. Monolithic active pixel radiation detector with shielding techniques

    Energy Technology Data Exchange (ETDEWEB)

    Deptuch, Grzegorz W.

    2016-09-06

    A monolithic active pixel radiation detector including a method of fabricating thereof. The disclosed radiation detector can include a substrate comprising a silicon layer upon which electronics are configured. A plurality of channels can be formed on the silicon layer, wherein the plurality of channels are connected to sources of signals located in a bulk part of the substrate, and wherein the signals flow through electrically conducting vias established in an isolation oxide on the substrate. One or more nested wells can be configured from the substrate, wherein the nested wells assist in collecting charge carriers released in interaction with radiation and wherein the nested wells further separate the electronics from the sensing portion of the detector substrate. The detector can also be configured according to a thick SOA method of fabrication.

  6. Evaluation of radiation dose reduction during CT scans by using bismuth oxide and nano-barium sulfate shields

    Science.gov (United States)

    Seoung, Youl-Hun

    2015-07-01

    The purpose of the present study was to evaluate the radiation dose reduction and the image quality during CT scanning by using a new dose reduction fiber sheet (DRFS) with commercially available bismuth shields. These DRFS, were composed of nano-barium sulfate (BaSO4) filling the gaps left by the large bismuth oxide (Bi2O3) particles. The radiation dose was measured five times at a direction of 12 o'clock from the center of the polymethyl methacrylate (PMMA) head phantom by using a CT ionization chamber to calculate an average value. The image quality of measured CT transverse images of the PMMA head phantom depended on the X-ray tube voltage and the type of shielding. Two regions of interest in the CT transverse images were chosen, one from the right area and the other from the left area under the surface of the PMMA head phantom and at a distance of ion chamber holes located in a direction of 12 o'clock from the center of the PMMA head phantom. The results of this study showed that the new DRFS shields could reduce the dosages by 15.61%, 23.05%, and 22.71% at 90 kVp, 120 kVp, and 140 kVp, respectively, than with these of a conventional bismuth shield of the same thickness while maintaining image quality. In addition, the DRFSs produced were about 25% thinness than conventional bismuth. We conclude, therefore, that a DRFS can replace conventional bismuth as a new shield.

  7. Neutron streaming studies along JET shielding penetrations

    OpenAIRE

    Stamatelatos Ion E.; Vasilopoulou Theodora; Batistoni Paola; Obryk Barbara; Popovichev Sergey; Naish Jonathan

    2017-01-01

    Neutronic benchmark experiments are carried out at JET aiming to assess the neutronic codes and data used in ITER analysis. Among other activities, experiments are performed in order to validate neutron streaming simulations along long penetrations in the JET shielding configuration. In this work, neutron streaming calculations along the JET personnel entrance maze are presented. Simulations were performed using the MCNP code for Deuterium-Deuterium and Deuterium- Tritium plasma sources. The ...

  8. Radiation exposure to foetus and breasts from dental X-ray examinations: effect of lead shields

    Science.gov (United States)

    Ekholm, Marja; Toroi, Paula; Kortesniemi, Mika

    2016-01-01

    Objectives: Dental radiography may involve situations where the patient is known to be pregnant or the pregnancy is noticed after the X-ray procedure. In such cases, the radiation dose to the foetus, though low, needs to be estimated. Uniform and widely used guidance on dental X-ray procedures during pregnancy are presently lacking, the usefulness of lead shields is unclear and practices vary. Methods: Upper estimates of radiation doses to the foetus and breasts of the pregnant patient were estimated with an anthropomorphic female phantom in intraoral, panoramic, cephalometric and CBCT dental modalities with and without lead shields. Results: The upper estimates of foetal doses varied from 0.009 to 6.9 μGy, and doses at the breast level varied from 0.602 to 75.4 μGy. With lead shields, the foetal doses varied from 0.005 to 2.1 μGy, and breast doses varied from 0.002 to 10.4 μGy. Conclusions: The foetal dose levels without lead shielding were <1% of the annual dose limit of 1 mSv for a member of the public. Albeit the relative shielding effect, the exposure-induced increase in the risk of breast cancer death for the pregnant patient (based on the breast dose only) and the exposure-induced increase in the risk of childhood cancer death for the unborn child are minimal, and therefore, need for foetal and breast lead shielding was considered irrelevant. Most important is that pregnancy is never a reason to avoid or to postpone a clinically justified dental radiographic examination. PMID:26313308

  9. Evaluating the Efficiency of the Device in Shielding Scattered Radiation during Treatment of Carcinoma of the Penis

    Energy Technology Data Exchange (ETDEWEB)

    Gim, Yang Soo; Lee, Sun Young; Lim, Suk Gun; Gwak, Geun Tak; Park, Ju Gyeong; Lee, Seung Hoon; Hwang, Ho In; Cha, Sook Yong [Dept. of Radiation Oncology, Chonbuk National University Hoispital, Jeonju (Korea, Republic of)

    2009-03-15

    We evaluated the device that was created for maintaining the patient's setup and protecting the testicles from scattered radiation during treatment of carcinoma of the penis. The phantom testicles were made of vaseline cotton gauze and the device consisted of 5 mm of acryl box and 4 mm of lead shielding. 3 x 3 cm{sup 2}, 4 x 4 cm{sup 2}, 5 x 5 cm{sup 2}, 6 x 6 cm{sup 2}, 7 x 7 cm{sup 2} field sizes were used for this study and measurement was made at 4, 5, 6, 7, 8, 10 cm from the lower edge of the field for 10 times with lead shielding and without the shielding respectively. 200 cGy was delivered using 6 MV photons. The scatted radiation without lead shielding at 4, 5, 6, 7, 8, 10 cm from the lower edge of the field were 14.8-4.7 cGy with 3 x 3 cm{sup 2}, 15.7-5.2 cGy with 4 x 4 cm{sup 2}, 17.6-5.5 cGy with 5 x 5 cm{sup 2}, 19.9-6.6 cGy with 6 x 6 cm{sup 2}, 22.2-7.6 cGy with 7 x 7 cm{sup 2} and the measured dose without lead shielding were 7.1-2.6 cGy with 3 x 3 cm{sup 2}, 8.9-3.6 cGy with 4 x 4 cm{sup 2}, 12.3-4.8 cGy with 5 x 5 cm{sup 2}, 14.6-5.0 cGy with 6 x 6 cm{sup 2} and 21.1-6.4 cGy with 7 x 7 cm{sup 2}. As shown above, the scatted radiation decreased after using lead shielding. Depending of the range of field sizes, the resulting difference between without shielding values and with shielding values were: 7.8-1.1 cGy at 4 cm, 5.1-1.2 cGy at 5 cm, 3.8-1.1 cGy at 6 cm, 3.4-1.7 cGy at 7 cm, 2.8-1.7 cGy at 8 cm, 2.4-2.5 cGy at 9 cm and 2.1-1.8 cGy at 10 cm. In the situation as described above, the range in values depending on the distance was 7.8-1.1 cGy with 3 x 3 cm{sup 2}, 6.9-1.6 cGy with 4 x 4 cm{sup 2}, 5.3-0.8 cGy with 5 x 5 cm{sup 2}, 5.3-1.5 cGy with 6 x 6 cm{sup 2} and 1.1-1.8 cGy with 7 x 7 cm{sup 2}. Using the device we created to shield the testicles from scattered radiation during treatment of carcinoma of the penis, we have found that scattered radiation to the testicles is decreased by the phantom testicles, and by increasing the distance

  10. Meeting the Grand Challenge of Protecting Astronauts Health: Electrostatic Active Space Radiation Shielding for Deep Space Missions

    Science.gov (United States)

    Tripathi, Ram K.

    2016-01-01

    This report describes the research completed during 2011 for the NASA Innovative Advanced Concepts (NIAC) project. The research is motivated by the desire to safely send humans in deep space missions and to keep radiation exposures within permitted limits. To this end current material shielding, developed for low earth orbit missions, is not a viable option due to payload and cost penalties. The active radiation shielding is the path forward for such missions. To achieve active space radiation shielding innovative large lightweight gossamer space structures are used. The goal is to deflect enough positive ions without attracting negatively charged plasma and to investigate if a charged Gossamer structure can perform charge deflections without significant structural instabilities occurring. In this study different innovative configurations are explored to design an optimum active shielding. In addition, to establish technological feasibility experiments are performed with up to 10kV of membrane charging, and an electron flux source with up to 5keV of energy and 5mA of current. While these charge flux energy levels are much less than those encountered in space, the fundamental coupled interaction of charged Gossamer structures with the ambient charge flux can be experimentally investigated. Of interest are, will the EIMS remain inflated during the charge deflections, and are there visible charge flux interactions. Aluminum coated Mylar membrane prototype structures are created to test their inflation capability using electrostatic charging. To simulate the charge flux, a 5keV electron emitter is utilized. The remaining charge flux at the end of the test chamber is measured with a Faraday cup mounted on a movable boom. A range of experiments with this electron emitter and detector were performed within a 30x60cm vacuum chamber with vacuum environment capability of 10-7 Torr. Experiments are performed with the charge flux aimed at the electrostatically inflated

  11. Radiation protection of staff in 111In radionuclide therapy--is the lead apron shielding effective?

    Science.gov (United States)

    Lyra, M; Charalambatou, P; Sotiropoulos, M; Diamantopoulos, S

    2011-09-01

    (111)In (Eγ = 171-245 keV, t1/2 = 2.83 d) is used for targeted therapies of endocrine tumours. An average activity of 6.3 GBq is injected into the liver by catheterisation of the hepatic artery. This procedure is time-consuming (4-5 min) and as a result, both the physicians and the technical staff involved are subjected to radiation exposure. In this research, the efficiency of the use of lead apron has been studied as far as the radiation protection of the working staff is concerned. A solution of (111)In in a cylindrical scattering phantom was used as a source. Close to the scattering phantom, an anthropomorphic male Alderson RANDO phantom was positioned. Thermoluminescent dosemeters were located in triplets on the front surface, in the exit and in various depths in the 26th slice of the RANDO phantom. The experiment was repeated by covering the RANDO phantom by a lead apron 0.25 mm Pb equivalent. The unshielded dose rates and the shielded photon dose rates were measured. Calculations of dose rates by Monte Carlo N-particle transport code were compared with this study's measurements. A significant reduction of 65 % on surface dose was observed when using lead apron. A decrease of 30 % in the mean absorbed dose among the different depths of the 26th slice of the RANDO phantom has also been noticed. An accurate correlation of the experimental results with Monte Carlo simulation has been achieved.

  12. Fabrication of Lightweight Radiation Shielding Composite Materials by Field Assisted Sintering Technique (FAST)

    Science.gov (United States)

    Prasad, Narasimha; Trivedi, Sudhir; Chen, Henry; Kutcher, Susan; Zhang, Dajie; Singh, Jogender

    2017-01-01

    Advances in radiation shielding technologies are needed to protect humans and electronic components from all threats of space radiation over long durations. In this paper, we report on the use of the innovative and novel fabrication technology known as Field Assisted Sintering Technology (FAST) to fabricate lightweight material with enhanced radiation shielding strength to safeguard humans and electronics suitable for next generation space exploration missions. The base materials we investigated were aluminum (Al), the current standard material for space hardware, and Ultra-High Molecular Weight Polyethylene (UHMWPE), which has high hydrogen content and resistance to nuclear reaction from neutrons, making it a good shielding material for both gamma radiation and particles. UHMWPE also has high resistance to corrosive chemicals, extremely low moisture sensitivity, very low coefficient of friction, and high resistance to abrasion. We reinforced the base materials by adding high density (ie, high atomic weight) metallic material into the composite. These filler materials included: boron carbide (B4C), tungsten (W), tungsten carbide (WC) and gadolinium (Gd).

  13. A temperature error correction method for a naturally ventilated radiation shield

    Science.gov (United States)

    Yang, Jie; Liu, Qingquan; Dai, Wei; Ding, Rrenhui

    2016-11-01

    Due to solar radiation exposure, air flowing inside a naturally ventilated radiation shield may produce a measurement error of 0.8 °C or higher. To improve the air temperature observation accuracy, a temperature error correction method is proposed. The correction method is based on a Computational Fluid Dynamics (CFD) method and a Genetic Algorithm (GA) method. The CFD method is implemented to analyze and calculate the temperature errors of a naturally ventilated radiation shield under various environmental conditions. Then, a temperature error correction equation is obtained by fitting the CFD results using the GA method. To verify the performance of the correction equation, the naturally ventilated radiation shield and an aspirated temperature measurement platform are characterized in the same environment to conduct the intercomparison. The aspirated temperature measurement platform serves as an air temperature reference. The mean temperature error given by measurements is 0.36 °C, and the mean temperature error given by correction equation is 0.34 °C. This correction equation allows the temperature error to be reduced by approximately 95%. The mean absolute error (MAE) and the root mean square error (RMSE) between the temperature errors given by the correction equation and the temperature errors given by the measurements are 0.07 °C and 0.08 °C, respectively.

  14. Investigation of some radiation shielding parameters in soft tissue

    Directory of Open Access Journals (Sweden)

    Danial Salehi

    2015-07-01

    Full Text Available The photon interactions with the soft tissue have been discussed mainly in terms of mass attenuation coefficient, mass energy absorption coefficient, kerma relative to air, effective atomic number and energy absorption buildup factor in the energy range 0.01–10 MeV and penetration depth up to 40 mfp (by using GP fitting method. Over past 2 decades, interest has been growing for theoretical and computational works on photon buildup factor in soft tissue. Actually, besides dosimetry, in radiation therapy and imaging the buildup of X- and gamma photons introduces remarkable error.

  15. Radiation Engineering Analysis of Shielding Materials to Assess Their Ability to Protect Astronauts in Deep Space From Energetic Particle Radiation

    Science.gov (United States)

    Singleterry, R. C.

    2013-01-01

    An analysis is performed on four typical materials (aluminum, liquid hydrogen, polyethylene, and water) to assess their impact on the length of time an astronaut can stay in deep space and not exceed a design basis radiation exposure of 150 mSv. A large number of heavy lift launches of pure shielding mass are needed to enable long duration, deep space missions to keep astronauts at or below the exposure value with shielding provided by the vehicle. Therefore, vehicle mass using the assumptions in the paper cannot be the sole shielding mechanism for long duration, deep space missions. As an example, to enable the Mars Design Reference Mission 5.0 with a 400 day transit to and from Mars, not including the 500 day stay on the surface, a minimum of 24 heavy lift launches of polyethylene at 89,375 lbm (40.54 tonnes) each are needed for the 1977 galactic cosmic ray environment. With the assumptions used in this paper, a single heavy lift launch of water or polyethylene can protect astronauts for a 130 day mission before exceeding the exposure value. Liquid hydrogen can only protect the astronauts for 160 days. Even a single launch of pure shielding material cannot protect an astronaut in deep space for more than 180 days using the assumptions adopted in the analysis. It is shown that liquid hydrogen is not the best shielding material for the same mass as polyethylene for missions that last longer than 225 days.

  16. Attenuation of X and Gamma Rays in Personal Radiation Shielding Protective Clothing.

    Science.gov (United States)

    Kozlovska, Michaela; Cerny, Radek; Otahal, Petr

    2015-11-01

    A collection of personal radiation shielding protective clothing, suitable for use in case of accidents in nuclear facilities or radiological emergency situations involving radioactive agents, was gathered and tested at the Nuclear Protection Department of the National Institute for Nuclear, Chemical and Biological Protection, Czech Republic. Attenuating qualities of shielding layers in individual protective clothing were tested via spectra measurement of x and gamma rays, penetrating them. The rays originated from different radionuclide point sources, the gamma ray energies of which cover a broad energy range. The spectra were measured by handheld spectrometers, both scintillation and High Purity Germanium. Different narrow beam geometries were adjusted using a special testing bench and a set of various collimators. The main experimentally determined quantity for individual samples of personal radiation shielding protective clothing was x and gamma rays attenuation for significant energies of the spectra. The attenuation was assessed comparing net peak areas (after background subtraction) in spectra, where a tested sample was placed between the source and the detector, and corresponding net peak areas in spectra, measured without the sample. Mass attenuation coefficients, which describe attenuating qualities of shielding layers materials in individual samples, together with corresponding lead equivalents, were determined as well. Experimentally assessed mass attenuation coefficients of the samples were compared to the referred ones for individual heavy metals.

  17. Boiling water reactor radiation shielded Control Rod Drive Housing Supports

    Energy Technology Data Exchange (ETDEWEB)

    Baversten, B.; Linden, M.J. [ABB Combustion Engineering Nuclear Operations, Windsor, CT (United States)

    1995-03-01

    The Control Rod Drive (CRD) mechanisms are located in the area below the reactor vessel in a Boiling Water Reactor (BWR). Specifically, these CRDs are located between the bottom of the reactor vessel and above an interlocking structure of steel bars and rods, herein identified as CRD Housing Supports. The CRD Housing Supports are designed to limit the travel of a Control Rod and Control Rod Drive in the event that the CRD vessel attachement went to fail, allowing the CRD to be ejected from the vessel. By limiting the travel of the ejected CRD, the supports prevent a nuclear overpower excursion that could occur as a result of the ejected CRD. The Housing Support structure must be disassembled in order to remove CRDs for replacement or maintenance. The disassembly task can require a significant amount of outage time and personnel radiation exposure dependent on the number and location of the CRDs to be changed out. This paper presents a way to minimize personal radiation exposure through the re-design of the Housing Support structure. The following paragraphs also delineate a method of avoiding the awkward, manual, handling of the structure under the reactor vessel during a CRD change out.

  18. Neutron streaming studies along JET shielding penetrations

    Directory of Open Access Journals (Sweden)

    Stamatelatos Ion E.

    2017-01-01

    Full Text Available Neutronic benchmark experiments are carried out at JET aiming to assess the neutronic codes and data used in ITER analysis. Among other activities, experiments are performed in order to validate neutron streaming simulations along long penetrations in the JET shielding configuration. In this work, neutron streaming calculations along the JET personnel entrance maze are presented. Simulations were performed using the MCNP code for Deuterium-Deuterium and Deuterium- Tritium plasma sources. The results of the simulations were compared against experimental data obtained using thermoluminescence detectors and activation foils.

  19. Design and fabrication of radiation shielded laser ablation ICP-MS system

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Yeong Keong; Han, Sun Ho; Park, Soon Dal; Park, Yang Soon; Jee, Kwang Yong; Kim, Won Ho

    2006-09-15

    In relation to high burn up and extended fuel cycle for the fuel cycle efficiency, we need to take chemical analysis of spent nuclear fuel for the integrity of nuclear fuel at high burn up. to measure the isotopic distribution of fission product in a high burn up nuclear fuel, radiation shielded laser ablation system was designed and fabricated. By probing the sample with a laser beam, micro sampling system for the mass analyzer was successfully developed. This report describes the structural design and the function of developed radiation shielded LA system. This system will be used for the analysis of isotopic distribution from core to rim of a spent nuclear fuel prepared from the hot-cell in PIE facility and/or an irradiated fuel from research reactor.

  20. Study of the radiation scattered and produced by concrete shielding of radiotherapy rooms and its effects on equivalent doses in patients' organs; Estudo da radiacao espalhada e produzida pela blindagem de concreto de salas de radioterapia e seus efeitos sobre doses equivalentes nos orgaos dos pacientes

    Energy Technology Data Exchange (ETDEWEB)

    Braga, K.L.; Rebello, W.F.; Andrade, E.R.; Gavazza, S.; Medeiros, M.P.C.; Mendes, R.M.S.; Gomes, R.G.; Silva, M.G., E-mail: kelmo.lins@gmail.com, E-mail: rebello@ime.eb.br, E-mail: fisica.dna@gmail.com, E-mail: sergiogavazza@yahoo.com, E-mail: eng.cavaliere@gmail.com, E-mail: raphaelmsm@gmail.com, E-mail: ggrprojetos@gmail.com, E-mail: maglosilva15@gmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Nuclear; Thalhofer, J.L.; Silva, A.X., E-mail: jardellt@yahoo.com.br, E-mail: ademir@con.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Energia Nuclear; Santos, R.F.G., E-mail: raphaelfgsantos@gmail.com [Centro Universitario Anhanguera, Niteroi, RJ (Brazil). Departamento de Engenharia

    2015-07-01

    Within a radiotherapy room, in addition to the primary beam, there is also secondary radiation due to the leakage of the accelerator head and the radiation scattering from room objects, patient and even the room's shielding itself, which is projected to protect external individuals disregarding its effects on the patient. This work aims to study the effect of concrete shielding wall over the patient, taking into account its contribution on equivalent doses. The MCNPX code was used to model the linear accelerator Varian 2100/2300 C/D operating at 18MeV, with MAX phantom representing the patient undergoing radiotherapy treatment for prostate cancer following Brazilian Institute of Cancer four-fields radiation application protocol (0°, 90°, 180° and 270°). Firstly, the treatment was patterned within a standard radiotherapy room, calculating the equivalent doses on patient's organs individually. In a second step, this treatment was modeled withdrawing the walls, floor and ceiling from the radiotherapy room, and then the equivalent doses calculated again. Comparing these results, it was found that the concrete has an average shielding contribution of around 20% in the equivalent dose on the patient's organs. (author)

  1. E-beam-Cure Fabrication of Polymer Fiber/Matrix Composites for Multifunctional Radiation Shielding

    Science.gov (United States)

    Wilson, John W.; Jensen, Brian J.; Thibeault, Sheila A.; Hou, Tan-Hung; Saether, Erik; Glaessgen, Edward H.; Humes, Donald H.; Chang, Chie K.; Badavi, Francis F.; Kiefer, Rrichard L.; hide

    2004-01-01

    Aliphatic polymers were identified as optimum radiation polymeric shielding materials for building multifunctional structural elements. Conceptual damage-tolerant configurations of polyolefins have been proposed but many issues on the manufacture remain. In the present paper, we will investigate fabrication technologies with e-beam curing for inclusion of high-strength aliphatic polymer fibers into a highly cross-linked polyolefin matrix. A second stage of development is the fabrication methods for applying face sheets to aliphatic polymer closed-cell foams.

  2. Shielding Design Aspects of SR Beamlines for 3-GeV And 8-GeV Class Synchrotron Radiation Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Asano, Yoshihiro; /JAERI-RIKEN, Hyogo; Liu, James C.; Rokni, Sayed; /SLAC

    2007-09-24

    Differences in synchrotron radiation beamline shielding design between the facilities of 3 GeV class and 8 GeV class are discussed with regard to SLAC SSRL and SPring-8 beamlines. Requirements of beamline shielding as well as the accelerator shielding depend on the stored electron energy, and here some factors in beamline shielding depending on the stored energy in particular, are clarified, namely the effect of build up, the effect of double scattering of photons at branch beamlines, and the spread of gas bremsstrahlung.

  3. Radiation Protection Effectiveness of Polymeric Based Shielding Materials at Low Earth Orbit

    Science.gov (United States)

    Badavi, Francis F.; Stewart-Sloan, Charlotte R.; Wilson, John W.; Adams, Daniel O.

    2008-01-01

    Correlations of limited ionizing radiation measurements onboard the Space Transportation System (STS; shuttle) and the International Space Station (ISS) with numerical simulations of charged particle transport through spacecraft structure have indicated that usage of hydrogen rich polymeric materials improves the radiation shielding performance of space structures as compared to the traditionally used aluminum alloys. We discuss herein the radiation shielding correlations between measurements on board STS-81 (Atlantis, 1997) using four polyethylene (PE) spheres of varying radii, and STS-89 (Endeavour, 1998) using aluminum alloy spheres; with numerical simulations of charged particle transport using the Langley Research Center (LaRC)-developed High charge (Z) and Energy TRaNsport (HZETRN) algorithm. In the simulations, the Galactic Cosmic Ray (GCR) component of the ionizing radiation environment at Low Earth Orbit (LEO) covering ions in the 1< or equals Z< or equals 28 range is represented by O'Neill's (2004) model. To compute the transmission coefficient for GCR ions at LEO, O'Neill's model is coupled with the angular dependent LaRC cutoff model. The trapped protons/electrons component of LEO environment is represented by a LaRC-developed time dependent procedure which couples the AP8min/AP8max, Deep River Neutron Monitor (DRNM) and F10.7 solar radio frequency measurements. The albedo neutron environment resulting from interaction of GCR ions with upper atmosphere is modeled through extrapolation of the Atmospheric Ionizing Radiation (AIR) measurements. With the validity of numerical simulations through correlation with PE and aluminum spheres measurements established, we further present results from the expansion of the simulations through the selection of high hydrogen content commercially available polymeric constituents such as PE foam core and Spectra fiber(Registered TradeMark) composite face sheet to assess their radiation shield properties as compared to

  4. Investigation of P(VDF-TrFE)/ZrO{sub 2}-MMA polymer composites applied to radiation shielding

    Energy Technology Data Exchange (ETDEWEB)

    Fontainha, C.C.P. [Depto. de Engenharia Nuclear - UFMG, Av. Antonio Carlos 6627, 31270-970 Belo Horizonte, MG (Brazil); Baptista Neto, A.T.; Santos, A.P.; Faria, L.O. [Centro de Desenvolvimento da Tecnologia Nuclear, Av. Antonio Carlos 6627, C.P. 941, 30270-901, Belo Horizonte, MG (Brazil)

    2015-07-01

    Exposure to high radiation dose in medical diagnostic imaging procedures can lead patients to suffer tissue damaging. However, there are several studies that identify significant dose reduction with the use of radiation protective attenuators, minimizing the delivered dose in the region that covers the main beam, while preserving the diagnostic quality of the generated image. Most radiation attenuator materials are produced from shielding metal containing composites, whose efficiency is the goal of investigations around the world. In this context, polymeric materials were chosen for this investigation in order to provide light-weighted and flexible protective composites, a must in personal protective shielding. Therefore, this work is concerned to the investigation of poly(vinylidene fluoride - try-fluor-ethylene) [P(VDF-TrFE)] copolymers mixed with zirconia nanoparticles. The resulting polymer composites, prepared with 1, 2, 3, 5 and 10 at.% of ZrO{sub 2} nanoparticles, were investigated for application as protective shielding in some interventional radiology procedures. Two variety of composites were produced, one using pure ZrO{sub 2} nanoparticles and the other using sol-gel route with zirconium butoxide as the precursor for zirconium oxide nano-clusters. The P(VDFTrFE)/ ZrO2-MMA polymer composites produced by sol-gel route have provided a much better dispersion of the pure ZrO{sub 2} material into the P(VDF-TrFE) host matrix. UV-Vis and FTIR spectrometry and differential scanning calorimetry (DSC) were used to characterize the composite samples. FTIR data reveal a possible link between the MMA monomers with the P(VDF-TrFE) chain through shared C=O bonds. The radiation shielding characterization was conducted by using a 70 kV x-rays beam which is applicable, for instances, in catheter angiography. The results demonstrate that composites with 10% of ZrO{sub 2}, and only 1.0 mm thick, can attenuate 60% of the x-rays beam. The composite density was evaluated to be

  5. UV radiation of the GTA welding plasma versus shielding gas composition

    Science.gov (United States)

    Ioffe, I.; Koss, V.; Perelman, N.; Hilton, D.

    1997-03-01

    UV radiation during gas tungsten arc (GTA) welding in argon/helium shielding gas mixtures versus gas composition and arc length has been investigated experimentally and theoretically. UV radiation was found to increase with an increase of argon concentration in the mixture. A physical model describing this phenomenon has been developed. The model predicts an increase in the total amount of ions in the mixture with an increase of argon concentration despite a decrease in plasma temperature. The result of calculations using the model is in satisfactory agreement with the experimental data.

  6. Radiation shielding evaluation based on five years of data from a busy CyberKnife center.

    Science.gov (United States)

    Yang, Jun; Feng, Jing

    2014-11-08

    We examined the adequacy of existing shielding guidelines using five-year clinical data from a busy CyberKnife center. From June 2006 through July 2011, 1,370 patients were treated with a total of 4,900 fractions and 680,691 radiation beams using a G4 CyberKnife. Prescription dose and total monitor units (MU) were analyzed to estimate the shielding workload and modulation factor. In addition, based on the beam's radiation source position, targeting position, MU, and beam collimator size, the MATLAB program was used to project each beam toward the shielding barrier. The summation of the projections evaluates the distribution of the shielding load. On average, each patient received 3.6 fractions, with an average 9.1 Gy per fraction prescribed at the 71.1% isodose line, using 133.7 beams and 6,200 MU. Intracranial patients received an average of 2.7 fractions, with 8.6 Gy per fraction prescribed at the 71.4% isodose line, using 133 beams and 5,083 MU. Extracranial patients received an average of 3.94 fractions, with 9.2 Gy per frac- tion prescribed at the 71% isodose line, using 134 beams and 6,514 MU. Most- used collimator sizes for intracranial patients were smaller (7.5 to 20 mm) than for extracranial patients (20 to 40 mm). Eighty-five percent of the beams exited through the floor, and about 40% of the surrounding wall area received no direct beam. For the rest of the wall, we found "hot" areas that received above-average MU. The locations of these areas were correlated with the projection of the nodes for extracranial treatments. In comparison, the beam projections on the wall were more spread for intracranial treatments. The maximum MU any area received from intracranial treatment was less than 0.25% of total MU used for intracranial treatments, and was less than 1.2% of total MU used for extracranial treatments. The combination of workload, modulation factor, and use factor in our practice are about tenfold less than recommendations in the existing Cyber

  7. Modeling the effectiveness of shielding in the earth-moon-mars radiation environment using PREDICCS: five solar events in 2012

    Science.gov (United States)

    Quinn, Philip R.; Schwadron, Nathan A.; Townsend, Larry W.; Wimmer-Schweingruber, Robert F.; Case, Anthony W.; Spence, Harlan E.; Wilson, Jody K.; Joyce, Colin J.

    2017-08-01

    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.

  8. Vacuum Ultraviolet Radiation and Atomic Oxygen Durability Evaluation of HST Bi-Stem Thermal Shield Materials

    Science.gov (United States)

    Dever, Joyce; deGroh, Kim K.

    2002-01-01

    Bellows-type thermal shields were used on the bi-stems of replacement solar arrays installed on the Hubble Space Telescope (HST) during the first HST servicing mission (SMI) in December 1993. These thermal shields helped reduce the problem of thermal gradient- induced jitter observed with the original HST solar arrays during orbital thermal cycling and have been in use on HST for eight years. This paper describes ground testing of the candidate solar array bi-stem thermal shield materials including backside aluminized Teflon(R)FEP (fluorinated ethylene propylene) with and without atomic oxygen (AO) and ultraviolet radiation protective surface coatings for durability to AO and combined AO and vacuum ultraviolet (VOV) radiation. NASA Glenn Research Center (GRC) conducted VUV and AO exposures of samples of candidate thermal shield materials at HST operational temperatures and pre- and post-exposure analyses as part of an overall program coordinated by NASA Goddard Space Flight Center (GSFC) to determine the on-orbit durability of these materials. Coating adhesion problems were observed for samples having the AO- and combined AO/UV-protective coatings. Coating lamination occurred with rapid thermal cycling testing which simulated orbital thermal cycling. This lack of adhesion caused production of coating flakes from the material that would have posed a serious risk to HST optics if the coated materials were used for the bi-stem thermal shields. No serious degradation was observed for the uncoated aluminized Teflon(R) as evaluated by optical microscopy, although atomic force microscopy (AFM) microhardness testing revealed that an embrittled surface layer formed on the uncoated Teflon(R) surface due to vacuum ultraviolet radiation exposure. This embrittled layer was not completely removed by AO erosion, No cracks or particle flakes were produced for the embrittled uncoated material upon exposure to VUV and AO at operational temperatures to an equivalent exposure of

  9. Study on textile comfort properties of polypropylene blended stainless steel woven fabric for the application of electromagnetic shielding effectiveness

    Science.gov (United States)

    Palanisamy, S.; Tunakova, V.; Karthik, D.; Ali, A.; Militky, J.

    2017-10-01

    In this study, the different proportion of conductive component blended with polypropylene yarn were taken for making conductive textile samples for analysis of electromagnetic shielding effectiveness, fabric bending moment and air permeability. The ASTM D4935 coaxial transmission line method was used to study the electromagnetic shielding. Electromagnetic shielding effectiveness of textile structures containing different percentage of metal content ranges from 1 to 50 dB at high frequency range. Breathability of structures, more precisely air permeability was considered as one of important parameters for designing of electromagnetic radiation protective fabrics for certain applications. The bending moment of samples is decreases with increasing metal component percent.

  10. A study of the electromagnetic shielding mechanisms in the GHz frequency range of graphene based composite layers

    Science.gov (United States)

    Drakakis, E.; Kymakis, E.; Tzagkarakis, G.; Louloudakis, D.; Katharakis, M.; Kenanakis, G.; Suchea, M.; Tudose, V.; Koudoumas, E.

    2017-03-01

    We report on the mechanisms of the electromagnetic interference shielding effect of graphene based paint like composite layers. In particular, we studied the absorption and reflection of electromagnetic radiation in the 4-20 GHz frequency of various dispersions employing different amounts of graphene nanoplatelets, polyaniline, and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), special attention given on the relative contribution of each process in the shielding effect. Moreover, the influence of the composition, the thickness and the conductivity of the composite layers on the electromagnetic shielding was also examined.

  11. Study on bulk shielding for a spallation neutron source facility in the high-intensity proton accelerator project

    CERN Document Server

    Maekawa, F; Takada, H; Teshigawara, M; Watanabe, N

    2002-01-01

    Under the JAERI-KEK High-Intensity Proton Accelerator Project, a spallation neutron source driven by a 3 GeV-1 MW proton beam is planed to be constructed in a main part of the Materials and Life Science Facility. This report describes results of a study on bulk shielding performance of a biological shield for the spallation neutron source by means of a Monte Carlo calculation method, that is important in terms of radiation safety and cost reduction. A shielding configuration was determined as a reference case by considering preliminary studies and interaction with other components, then shielding thickness that was required to achieve a target dose rate of 1 mu Sv/h was derived. Effects of calculation conditions such as shielding materials and dimensions on the shielding performance was investigated by changing those parameters. By taking all the results and design margins into account, a shielding configuration that was identified as the most appropriate was finally determined as follows. An iron shield regi...

  12. Natural fibre high-density polyethylene and lead oxide composites for radiation shielding

    CERN Document Server

    El-Sayed, A; Ismail, M R

    2003-01-01

    Study has been made of the radiation shielding provided by recycled agricultural fibre and industrial plastic wastes produced as composite materials. Fast neutron and gamma-ray spectra behind composites of fibre-plastic (rho = 1.373 g cm sup - sup 3) and fibre-plastic-lead (rho = 2.756 g cm sup - sup 3) have been measured using a collimated reactor beam and neutron-gamma spectrometer with a stilbene scintillator. The pulse shape discriminating technique based on the zero-cross-over method was used to discriminate between neutron and gamma-ray pulses. Slow neutron fluxes have been measured using a collimated reactor beam and BF sub 3 counter, leading to determination of the macroscopic cross-section (SIGMA). The removal cross-sections (SIGMA sub R) of fast neutrons have been determined from measured results and elemental composition of the composites. For gamma-rays, total linear attenuation coefficients (mu) and total mass attenuation coefficients (mu/rho) have been determined from use of the XCOM code and me...

  13. Neutron Radiation Shielding For The NIF Streaked X-Ray Detector (SXD) Diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Song, P; Holder, J; Young, B; Kalantar, D; Eder, D; Kimbrough, J

    2006-11-02

    The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) is preparing for the National Ignition Campaign (NIC) scheduled in 2010. The NIC is comprised of several ''tuning'' physics subcampaigns leading up to a demonstration of Inertial Confinement Fusion (ICF) ignition. In some of these experiments, time-resolved x-ray imaging of the imploding capsule may be required to measure capsule trajectory (shock timing) or x-ray ''bang-time''. A capsule fueled with pure tritium (T) instead of a deutriun-tritium (DT) mixture is thought to offer useful physics surrogacy, with reduced yields of up to 5e14 neutrons. These measurements will require the use of the NIF streak x-ray detector (SXD). The resulting prompt neutron fluence at the planned SXD location ({approx}1.7 m from the target) would be {approx}1.4e9/cm{sup 2}. Previous measurements suggest the onset of significant background at a neutron fluence of {approx} 1e8/cm{sup 2}. The radiation damage and operational upsets which starts at {approx}1e8 rad-Si/sec must be factored into an integrated experimental campaign plan. Monte Carlo analyses were performed to predict the neutron and gamma/x-ray fluences and radiation doses for the proposed diagnostic configuration. A possible shielding configuration is proposed to mitigate radiation effects. The primary component of this shielding is an 80 cm thickness of Polyethylene (PE) between target chamber center (TCC) and the SXD diagnostic. Additionally, 6-8 cm of PE around the detector provide from the large number of neutrons that scatter off the inside of the target chamber. This proposed shielding configuration reduces the high-energy neutron fluence at the SXD by approximately a factor {approx}50.

  14. Shielding data for hadron-therapy ion accelerators: Attenuation of secondary radiation in concrete

    CERN Document Server

    Agosteo, S; Sagia, E; Silari, M

    2014-01-01

    The secondary radiation field produced by seven different ion species (from hydrogen to nitrogen), impinging onto thick targets made of either iron or ICRU tissue, was simulated with the FLUKA Monte Carlo code, and transported through thick concrete shields: the ambient dose equivalent was estimated and shielding parameters evaluated. The energy for each ion beam was set in order to reach a maximum penetration in ICRU tissue of 290 mm (equivalent to the therapeutic range of 430 MeV/amu carbon ions). Source terms and attenuation lengths are given as a function of emission angle and ion species, along with fits to the Monte Carlo data, for shallow depth and deep penetration in the shield. Trends of source terms and attenuation lengths as a function of neutron emission angle and ion species impinging on tar- get are discussed. A comparison of double differential distributions of neutrons with results from similar simulation works reported in the literature is also included. The aim of this work is to provide shi...

  15. Bibliography, subject index, and author index of the literature examined by the Radiation Shielding Information Center. Volume 7

    Energy Technology Data Exchange (ETDEWEB)

    Trubey, D.K.; Roussin, R.W.; Gustin, A.B.

    1983-08-01

    An indexed bibliography of open literature selected by the Radiation Shielding Information Center since the previous volume was published in 1980 is presented in the area of radiation transport and shielding against radiation from nuclear reactors (fission and fusion), x-ray machines, radioisotopes, nuclear weapons (including fallout, and low energy accelerators (e.g., neutron generators). The bibliography was typeset from computer files constituting the RSIC Storage and Retrieval Information System. In addition to lists of literature titles by subject categories (accessions 6201-10156), an author index is given. Most of the literature selected for Volume VII was published in the years 1977 to 1981.

  16. Modelling human exposure to space radiation with different shielding: the FLUKA code coupled with anthropomorphic phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Ballarini, F [Department of Nuclear and Theoretical Physics, University of Pavia (Italy); Alloni, D [Department of Nuclear and Theoretical Physics, University of Pavia (Italy); Battistoni, G [INFN - National Institute of Nuclear Physics, (Italy); Cerutti, F [INFN - National Institute of Nuclear Physics (Italy)] (and others)

    2006-05-15

    Astronauts' exposure to the various components of the space radiation field is of great concern for long-term missions, especially for those in deep space such as a possible travel to Mars. Simulations based on radiation transport/interaction codes coupled with anthropomorphic model phantoms can be of great help in view of risk evaluation and shielding optimisation, which is therefore a crucial issue. The FLUKA Monte Carlo code can be coupled with two types of anthropomorphic phantom (a mathematical model and a 'voxel' model) to calculate organ-averaged absorbed dose, dose equivalent and 'biological' dose under different shielding conditions. Herein the 'biological dose' is represented by the average number of 'Complex Lesions' (CLs) per cell in a given organ. CLs are clustered DNA breaks previously calculated by means of event-by-event track structure simulations at the nm level and integrated on-line into FLUKA, which adopts a condensed-history approach; such lesions have been shown to play a fundamental role in chromosome aberration induction, which in turn can be correlated with carcinogenesis. Examples of calculation results will be presented relative to Galactic Cosmic Rays, as well as to the August 1972 Solar Particle Event. The contributions from primary ions and secondary particles will be shown separately, thus allowing quantification of the role played by nuclear reactions occurring in the shield and in the human body itself. As expected, the SPE doses decrease dramatically with increasing the Al shielding thickness; nuclear reaction products, essentially due to target fragmentation, are of minor importance. A 10 g/cm{sup 2} Al shelter resulted to be sufficient to respect the 30-day limits for deterministic effects recommended for missions in Low Earth Orbit. In contrast with the results obtained for SPEs, the calculated GCR doses are almost independent of the Al shield thickness, and the GCR doses to internal

  17. Assessment of shielding analysis methods, codes, and data for spent fuel transport/storage applications. [Radiation dose rates from shielded spent fuels and high-level radioactive waste

    Energy Technology Data Exchange (ETDEWEB)

    Parks, C.V.; Broadhead, B.L.; Hermann, O.W.; Tang, J.S.; Cramer, S.N.; Gauthey, J.C.; Kirk, B.L.; Roussin, R.W.

    1988-07-01

    This report provides a preliminary assessment of the computational tools and existing methods used to obtain radiation dose rates from shielded spent nuclear fuel and high-level radioactive waste (HLW). Particular emphasis is placed on analysis tools and techniques applicable to facilities/equipment designed for the transport or storage of spent nuclear fuel or HLW. Applications to cask transport, storage, and facility handling are considered. The report reviews the analytic techniques for generating appropriate radiation sources, evaluating the radiation transport through the shield, and calculating the dose at a desired point or surface exterior to the shield. Discrete ordinates, Monte Carlo, and point kernel methods for evaluating radiation transport are reviewed, along with existing codes and data that utilize these methods. A literature survey was employed to select a cadre of codes and data libraries to be reviewed. The selection process was based on specific criteria presented in the report. Separate summaries were written for several codes (or family of codes) that provided information on the method of solution, limitations and advantages, availability, data access, ease of use, and known accuracy. For each data library, the summary covers the source of the data, applicability of these data, and known verification efforts. Finally, the report discusses the overall status of spent fuel shielding analysis techniques and attempts to illustrate areas where inaccuracy and/or uncertainty exist. The report notes the advantages and limitations of several analysis procedures and illustrates the importance of using adequate cross-section data sets. Additional work is recommended to enable final selection/validation of analysis tools that will best meet the US Department of Energy's requirements for use in developing a viable HLW management system. 188 refs., 16 figs., 27 tabs.

  18. Preparation and characterisation of Isophthalic-Bi2O3 polymer composite gamma radiation shields

    Science.gov (United States)

    Ambika, M. R.; Nagaiah, N.; Harish, V.; Lokanath, N. K.; Sridhar, M. A.; Renukappa, N. M.; Suman, S. K.

    2017-01-01

    Bi2O3 filled Isophthalic resin based polymer composites of different weight % (0, 5, 10, 20, 30, 40, 50 & 60) were fabricated by open mould cast technique. Gamma attenuation study was carried out using NaI (Tl) gamma ray spectrometer for Cs-137. The shielding parameters such as attenuation coefficient, HVL & λ were investigated. The distribution of the filler within the matrix was studied using Scanning Electron Microscopy. X ray diffractometer and Fourier Transform Infrared Spectroscopy were employed to study the structural changes if any. The thermal stability and mechanical strength of the composites were investigated using TGA & UTM respectively. Dielectric properties and AC conductivity were also studied using LCR meter. The composites are found to be thermally stable upto 200 °C. There were no such structural changes observed and all the composites show very low conductivity. The mechanical strength of the composites was found to increase upon adding the bismuth oxide with a slight decrease when the concentration of the filler exceeds 40 wt%. Attenuation results reveal that, the shielding efficiency increases with the increase of the filler wt% and are comparable to those of the conventional shielding materials. Hence, Bi2O3 filled composites can be used for gamma shielding applications.

  19. Experimental investigation on the effect of high Z front layer on saturation thickness for radiation shielding materials

    Science.gov (United States)

    Purkayastha, Biswajit

    Measurement of number and energy albedo of backscattered gamma rays has wide applications in the design of gamma ray shield involving the use of nuclear radiations. In these applications the characteristic parameter which gives an integral measurement of gamma ray scattering is the albedo of the material involved. Albedo measurements were initiated at the end of the fifth decade of the present century, just after the 2nd World War. Large number of workers worked in different fields such as (i) measurement of angular and energy distributions of backscattered in photons by applying Monte Carlo technique, (ii) experimental investigations of backscattering gamma rays by scintillation spectrometer, Uniform Sensitivity Photon Counter, Proportional Response Photon Counter etc. However, the literature on the effect of high atomic number (Z) front layer on the saturation thickness of a gamma radiation shield is almost nil. In view of the above discussions attempts have been made in the present investigation to extend the scope for optimisation of saturation thickness of a radiation shield by placing a high Z front layer material of varying thickness. Measurements of energy albedo for a homogeneous shield with and without a front layer of different high Z material of varying thickness for two energies namely 662 keV and 1250 keV have been carried out and a careful analysis is presented in the present investigation. From a detailed analysis of the present investigation the following conclusions can be drawn : (i) Anisotroplc distributions of photons as function of emerging angle. (ii) Total energy albedo values of different shielding materials decrease when high Z material is used in front of the shielding material. (iii) Saturation thickness of scattering combinations depends on Z values of the front layer. (iv) The total energy albedo values decrease exponentially as the increase in thickness of the high Z material of the front layer. (v) This experiment not only throws

  20. Information center as a technical institute unifying a user community. [Exemplified by Radiation Shielding Information Center at ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Maskewitz, B.F.; McGill, B.; Hatmaker, N.A.

    1976-01-01

    The historical background to the information analysis center concept is presented first. The Radiation Shielding Information Center (RSIC) at ORNL is cited as an example of the information analysis center. RSIC objectives and scope are described, and RSIC's role in unification of the field of shielding is discussed. Some problems in handling information exchange with respect to computer codes are examined. (RWR)

  1. Recent developments in the TRIPOLI-4® Monte-Carlo code for shielding and radiation protection applications

    Science.gov (United States)

    Malouch, Fadhel; Brun, Emeric; Diop, Cheikh; Hugot, François-Xavier; Jouanne, Cédric; Lee, Yi-Kang; Malvagi, Fausto; Mancusi, Davide; Mazzolo, Alain; Petit, Odile; Trama, Jean-Christophe; Visonneau, Thierry; Zoia, Andrea

    2017-09-01

    TRIPOLI-4® is a 3D continuous-energy Monte-Carlo particle transport code developed by CEA (SERMA) and devoted to shielding, reactor physics, criticality-safety and nuclear instrumentation. In this paper, we present the recent developments in the TRIPOLI-4® for shielding and radiation protection applications. Some of these additional features are already available in the TRIPOLI-4® version 10 released in December 2015. Other features are in development.

  2. Shielding for Critical Organs and Radiation Exposure Dose Distribution in Patients with High Energy Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Sung Sil; Suh, Chang Ok; Kim, Gwi Eon [Yonsei Univ., Seoul (Korea, Republic of)

    2002-03-15

    High energy photon beams from medical linear accelerators produce large scattered radiation by various components of the treatment head, collimator and walls or objects in the treatment room including the patient. These scattered radiation do not provide therapeutic dose and are considered a hazard from the radiation safety perspective. Scattered dose of therapeutic high energy radiation beams are contributed significant unwanted dose to the patient. ICRP take the position that a dose of 500mGy may cause abortion at any stage of pregnancy and that radiation detriment to the fetus includes risk of mental retardation with a possible threshold in the dose response relationship around 100 mGy for the gestational period. The ICRP principle of As Low As Reasonably Achievable (ALARA) was recommended for protection of occupation upon the linear no-threshold dose response hypothesis for cancer induction. We suggest this ALARA principle be applied to the fetus and testicle in therapeutic treatment. Radiation dose outside a photon treatment filed is mostly due to scattered photons . This scattered dose is a function of the distance from the beam edge, treatment geometry, primary photon energy, and depth in the patient. The need for effective shielding of the fetus and testicle is reinforced when young patients are treated with external beam radiation therapy and then shielding designed to reduce the scattered photon dose to normal organs have to considered. Irradiation was performed in phantom using high energy photon beams produced by a Varian 2100C/D medical linear accelerator (Varian Oncology Systems, Polo Alto, CA) located at the Yonsei Cancer Center. The composite phantom used was comprised of a commercially available anthropomorphic Rando phantom (Phantom Laboratory Inc., Salem, YN) and a rectangular solid polystyrene phantom of dimensions 30cm x 30cm x 20cm. The anthropomorphic Rando phantom represents an average man made from tissue equivalent materials that is

  3. Is lead shielding of patients necessary during fluoroscopic procedures? A study based on kyphoplasty.

    Science.gov (United States)

    Smith, Joshua R; Marsh, Rebecca M; Silosky, Michael S

    2018-01-01

    To determine the benefits, risks, and limitations associated with wrapping a patient with lead shielding during fluoroscopy-guided kyphoplasty procedures as a way to reduce operator radiation exposure. An anthropomorphic phantom was used to mimic a patient undergoing a kyphoplasty procedure under fluoroscopic guidance. Radiation measurements of the air kerma rate (AKR) were made at several locations and under various experimental conditions. First, AKR was measured at various angles along the horizontal plane of the phantom and at varying distances from the phantom, both with and without a lead apron wrapped around the lower portion of the phantom (referred to here as phantom shielding). Second, the effect of an operator's apron was simulated by suspending a lead apron between the phantom and the measurement device. AKR was measured for the four shielding conditions-phantom shielding only, operator apron only, both phantom shielding and operator apron, and no shielding. Third, AKR measurements were made at various heights and with varying C-arm angle. At all locations, the phantom shielding provided no substantial protection beyond that provided by an operator's own lead apron. Phantom shielding did not reduce AKR at a height comparable to that of an operator's head. Previous reports of using patient shielding to reduce operator exposure fail to consider the role of an operator's own lead apron in radiation protection. For an operator wearing appropriate personal lead apparel, patient shielding provides no substantial reduction in operator dose.

  4. A radiation emission shielding method for high intensity focus ultrasound probes.

    Science.gov (United States)

    Wu, Hao; Shen, Guofeng; Chen, Yazhu

    2015-01-01

    Electromagnetic compatibility (EMC) is a key issue in the design and development of safe and effective medical instruments. The treatment probes of high intensity focused ultrasound (HIFU) systems not only receive and transmit electromagnetic waves, but also radiate ultrasound waves, resulting in electromagnetic coupling. In this paper, an electromagnetic shielding method involving the enclosure of the probe in a copper wire mesh was introduced. First, sound pressure distribution simulations and measurements were performed using a hydrophone in order to evaluate the effects of the wire mesh on the acoustic performance of the HIFU system. The results indicated that the wire mesh did not disturb the normalized sound pressure field. In addition, the attenuation of the maximum pressure in the focal plane was equal to 6.2%. Then, the electronic emission level was tested in a chamber. After the implementation of the wire mesh, the 10-100 MHz frequency band radiation was suppressed, and the HIFU system satisfied the national EMC standards.

  5. Characterization of Radiation Fields in Biological Shields of Nuclear Power Plants for Assessing Concrete Degradationa

    Energy Technology Data Exchange (ETDEWEB)

    Remec, Igor [ORNL; Rosseel, Thomas M [ORNL; Field, Kevin G [ORNL; Le Pape, Yann [ORNL

    2016-01-01

    Life extensions of nuclear power plants to 60 and potentially 80 years of operation have renewed interest in long-term material degradation. One material being considered is concrete, with a particular focus on radiation-induced effects. Based on the projected neutron fluence values (E > 0.1 MeV) in the concrete biological shields of the US pressurized water reactor fleet and the available data on radiation effects on concrete, some decrease in mechanical properties of concrete cannot be ruled out during extended operation beyond 60 years. An expansion of the irradiated concrete database and a reliable determination of relevant neutron fluence energy cutoff value are necessary to ensure reliable risk assessment for extended operation of nuclear power plants.

  6. 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.

  7. Neutron and gamma flux distributions and their implications for radiation damage in the shielded superconducting core of a fusion power plant

    Science.gov (United States)

    Windsor, Colin G.; Morgan, J. Guy

    2017-11-01

    The neutron and gamma ray fluxes within the shielded high-temperature superconducting central columns of proposed spherical tokamak power plants have been studied using the MCNP Monte-Carlo code. The spatial, energy and angular variations of the fluxes over the shield and superconducting core are computed and used to specify experimental studies relevant to radiation damage and activation. The mean neutron and gamma fluxes, averaged over energy and angle, are shown to decay exponentially through the shield and then to remain roughly constant in the core region. The mean energy of neutrons is shown to decay more slowly than the neutron flux through the shield while the gamma energy is almost constant around 2 MeV. The differential neutron and gamma fluxes as a function of energy are examined. The neutron spectrum shows a fusion peak around 1 MeV changing at lower energies into an epithermal E -0.85 variation and at thermal energies to a Maxwellian distribution. The neutron and gamma energy spectra are defined for the outer surface of the superconducting core, relevant to damage studies. The inclusion of tungsten boride in the shield is shown to reduce energy deposition. A series of plasma scenarios with varying plasma major radii between 0.6 and 2.5 m was considered. Neutron and gamma fluxes are shown to decay exponentially with plasma radius, except at low shield thickness. Using the currently known experimental fluence limitations for high temperature superconductors, the continuous running time before the fluence limit is reached has been calculated to be days at 1.4 m major radius increasing to years at 2.2 m. This work helps validate the concept of the spherical tokamak route to fusion power by demonstrating that the neutron shielding required for long lifetime fusion power generation can be accommodated in a compact device.

  8. Abstracts of digital computer code packages assembled by the Radiation Shielding Information Center

    Energy Technology Data Exchange (ETDEWEB)

    Carter, B.J.; Maskewitz, B.F.

    1985-04-01

    This publication, ORNL/RSIC-13, Volumes I to III Revised, has resulted from an internal audit of the first 168 packages of computing technology in the Computer Codes Collection (CCC) of the Radiation Shielding Information Center (RSIC). It replaces the earlier three documents published as single volumes between 1966 to 1972. A significant number of the early code packages were considered to be obsolete and were removed from the collection in the audit process and the CCC numbers were not reassigned. Others not currently being used by the nuclear R and D community were retained in the collection to preserve technology not replaced by newer methods, or were considered of potential value for reference purposes. Much of the early technology, however, has improved through developer/RSIC/user interaction and continues at the forefront of the advancing state-of-the-art.

  9. Strain-related differences and radiation quality effects on mouse leukocytes: gamma-rays and protons (with and without aluminum shielding).

    Science.gov (United States)

    Gridley, Daila S; Pecaut, Michael J; Green, Lora M; Sanchez, Martha C; Kadhim, Munira A

    2011-01-01

    Increasing evidence indicates that radiation-induced genomic instability plays an important role in the development of cancer. However, radiation quality and genetic background can influence the outcome. The goal of this study was to quantify radiation-induced changes in lymphocyte populations in mouse strains known to differ in susceptibility to genomic instability (C57BL/6, resistant; CBA/Ca, susceptible). The effects of whole-body exposure to γ-rays and protons, with and without aluminum shielding, were compared. Total radiation doses of 0, 0.1, 0.5, and 2.0 Gy were delivered and subsets of mice from each group were euthanized on days 1 and 30 after exposure for spleen and bone marrow analyses. In the spleen on day 1, lymphocyte counts were decreased (p<0.05) in C57, but not CBA, mice irradiated with 2 Gy. By day 30 in the C57 strain, counts were still low in the group exposed to 2 Gy shielded protons. Some strain- and radiation-dependent differences were also noted in percentages of specific lymphocyte populations (T, B, NK) and the CD4:CD8 ratio. In bone marrow, percentages of stem/progenitor cells (CD34(+), Ly-6A/E(+), CD34(+)Ly-6A/E(+)) were generally highest 1 day after 2 Gy irradiation, regardless of strain and radiation type. Based on dUTP incorporation, bone marrow cells from C57 mice had consistently higher levels of DNA damage on day 30 after irradiation with doses less than 2 Gy, regardless of quality. Annexin V binding supported the conclusion that C57 bone marrow cells were more susceptible to radiation-induced apoptosis. Overall, the data indicate that leukocytes of CBA mice are less sensitive to the effects of high-linear energy transfer radiation (shielded protons) than C57 mice, a phenomenon consistent with increased possibility for genomic instability and progression to a malignant cell phenotype after sublethal damage.

  10. Mass attenuation coefficients of X-rays in different barite concrete used in radiation protection as shielding against ionizing radiation

    Science.gov (United States)

    Almeida Junior, T. Airton; Nogueira, M. S.; Vivolo, V.; Potiens, M. P. A.; Campos, L. L.

    2017-11-01

    The probability of a photon interacting in a particular way with a given material, per unit path length, is usually called the linear attenuation coefficient (μ), and it is of great importance in radiation shielding. Plates of barite concrete with different thickness were fabricated in order to determining their mass attenuation coefficients at different energies. The plates were irradiated with ISO X-ray beams (N60, N80, N110 and N150), generated by Pantak HF320 X-ray equipment, at the IPEN laboratory. The mass attenuation coefficients of barite concrete have been measured using X-ray attenuation for different thicknesses of barite concrete qualities of the ISO. The attenuator material issued from different regions of Brazil. The experimental procedure in this research was validated by comparison between the experimental measurements of mass attenuation coefficients and coefficients determined by the same atomic composition, using as a tool to XCOM. The highest value of (μ/ρ) found experimentally was in the energy of 48 keV, in ISO 60 N quality, being 1.32(±0.49) for purple barite; 1.47(±0.41) for white barite and 1.75(±0.41) for cream barite. The determination of the chemical composition of the barite samples was of fundamental importance for the characterization of these materials. It can be seen that both calculated and measured data for the linear attenuation coefficients increase with the increasing materials density, as it is expected. It can be concluded that the photon attenuation coefficients depends on the photon energy and the materials density is the main contribution to the photon attenuation coefficients, which is important for radiation shielding.

  11. SU-E-T-243: Design of a Novel Testing Port for Radiation Protection and Shielding Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Tanny, S; Parsai, E [University of Toledo Medical Center, Toledo, OH (United States); Harrell, D; Noller, J [Shielding Construction Solutions, Inc, Tuscon, AZ (United States); Chopra, M [Unviersal Minerals International, Inc, Tuscon, AZ (United States)

    2015-06-15

    Purpose: The majority of radiation shielding research utilizes Monte Carlo simulation because of the difficulty in eliminating secondary radiations from measurements. We have designed a test port into a primary barrier of our newest vault to allow for shielding measurements while ensuring adequate protection to the public and staff during normal machine operation. This port allows for measurement of attenuation values of shielding materials, differential dose albedos, and radiation scatter fractions. Methods: The vault design utilized the maze as part of a compound primary barrier. The test port is contained within the maze and is centered along isocenter. The inner 30 cm has a 20×20 cm{sup 2} opening, while the remaining length has a 30×30 cm{sup 2} opening. The block that contains the port has a density of 200 pcf to minimize internal scatter. The 30×30 cm{sup 2} opening is occupied by removable 215 pcf concrete blocks. The innermost and outermost blocks activate an interlock wired into the beam-enable loop. This disallows beam-on in treatment mode if the interlock isn’t closed. The interlock can be overridden in service mode, or by-passed via an override switch in case of circuit failure. Results: The test port was installed in August. The beam is disabled when the interlock is tripped. Measurements taken when the primary beam is not incident on the port are indistinguishable from background. Ambient dose levels surrounding the vault with the designed shielding blocks in place are all within allowable limits for occupational workers. Conclusions: We have designed and installed a unique testing port for radiation protection and shielding measurements. This port is appropriately interlocked and designed to mitigate any risks of incidental exposure to staff or members of the public. The test port design allows measurements with “good geometry” and efficient removal of contaminating sources of radiation present in many shielding measurements. Daniel Harrell

  12. Identification of best particle radiation shielded region through Energetic Neutral Atoms mapping

    Science.gov (United States)

    Milillo, A.; De Angelis, E.; Mura, A.; Orsini, S.; Mangano, V.; Massetti, S.; Rispoli, R.; Lazzarotto, F.; Vertolli, N.; Lavagna, M.; Ferrari, F.; Lunghi, P.; Attinà, P.; Parissenti, G.

    2017-09-01

    The lunar surface is directly exposed either to direct solar wind, or to Earth's magnetospheric plasma due to the Moon's lack of a magnetosphere or a dense atmosphere. This exposure could create inhospitable conditions for a possible human presence on the Moon, so it is crucial to investigate the close-to-surface environment for establishing the best reliable locations for future human bases. Although it lacks a global magnetic field, the Moon possesses magnetic anomalies that create mini-magnetospheres, where the solar wind is partly deflected. The local protection of the surface from the solar wind radiation inside the mini-magnetospheres could make these sites preferred for future lunar colonization. It is crucial a detailed characterization of these sites. In this paper, an investigation based on the detection of Energetic Neutral Atoms (ENA) from the surface for identifying the best particle radiation shielded region is proposed. A high spatial resolution mapping via ENA is a feasible and it is powerful way for reaching this goal.

  13. Modelling of neutron and photon transport in iron and concrete radiation shieldings by the Monte Carlo method - Version 2

    CERN Document Server

    Žukauskaite, A; Plukiene, R; Plukis, A

    2007-01-01

    Particle accelerators and other high energy facilities produce penetrating ionizing radiation (neutrons and γ-rays) that must be shielded. The objective of this work was to model photon and neutron transport in various materials, usually used as shielding, such as concrete, iron or graphite. Monte Carlo method allows obtaining answers by simulating individual particles and recording some aspects of their average behavior. In this work several nuclear experiments were modeled: AVF 65 – γ-ray beams (1-10 MeV), HIMAC and ISIS-800 – high energy neutrons (20-800 MeV) transport in iron and concrete. The results were then compared with experimental data.

  14. Characterization of the Radiation Shielding Properties of US andRussian EVA Suits

    Energy Technology Data Exchange (ETDEWEB)

    Benton, E.R.; Benton, E.V.; Frank, A.L.

    2001-10-26

    Reported herein are results from the Eril Research, Inc.(ERI) participationin the NASA Johnson Space Center sponsored studycharacterizing the radiation shielding properties of the two types ofspace suit that astronauts are wearing during the EVA on-orbit assemblyof the International Space Station (ISS). Measurements using passivedetectors were carried out to assess the shielding properties of the USEMU Suit and the Russian Orlan-M suit during irradiations of the suitsand a tissue equivalent phantom to monoenergetic proton and electronbeams at the Loma Linda University Medical Center (LLUMC). Duringirradiations of 6 MeV electrons and 60 MeV protons, absorbed dose as afunction of depth was measured using TLDs exposed behind swatches of thetwo suit materials and inside the two EVA helmets. Considerable reductionin electron dosewas measured behind all suit materials in exposures to 6MeV electrons. Slowing of the proton beam in the suit materials led to anincrease in dose measured in exposures to 60 MeV protons. During 232 MeVproton irradiations, measurements were made with TLDs and CR-39 PNTDs atfive organ locations inside a tissue equivalent phantom, exposed bothwith and without the two EVA suits. The EVA helmets produce a 13 to 27percent reduction in total dose and a 0 to 25 percent reduction in doseequivalent when compared to measurements made in the phantom head alone.Differences in dose and dose equivalent between the suit and non-suitirradiations forthe lower portions of the two EVA suits tended to besmaller. Proton-induced target fragmentation was found to be asignificant source of increased dose equivalent, especially within thetwo EVA helmets, and average quality factor inside the EMU and Orlan-Mhelmets was 2 to 14 percent greater than that measured in the barephantom head.

  15. A special radiation shielding for the radiotherapy of a pregnant patient; Eine Spezialabschirmung fuer die Strahlentherapie von Schwangeren

    Energy Technology Data Exchange (ETDEWEB)

    Buchgeister, M.; Mondry, A. [Bereich Medizinische Physik, Universitaetsklinik fuer Radioonkologie, Tuebingen (Germany); Spillner, P.; Paulsen, F.; Belka, C.; Bamberg, M. [Strahlentherapie, Universitaetsklinik fuer Radioonkologie, Tuebingen (Germany)

    2008-02-15

    Purpose: measurement of the radiation dose of different radiotherapy techniques with a phantom at the position of the uterus of a pregnant patient with and without a special radiation shielding. Material and methods: a special radiation shielding for the radiation therapy of a pregnant patient was constructed in the shape of a tunnel over the abdomen from 1 cm thick lead to reduce scatter radiation to the uterus and the fetus therein. The reduction of the scatter radiation to the lower abdomen was measured for three typical cases (cerebrum with lateral opposed fields, 6-MV photons; tangential fields for mamma irradiation, 6 MV; and anteroposterior-posteroanterior [AP-PA] opposed fields of 15 MV for treatment of the mediastinum) at an anthropomorphic Alderson phantom with thermoluminescence dosimeters in different depths and with an ionization chamber positioned in an RW3 solid water phantom. In the case of lateral opposed fields, a movable lead wall was additionally positioned next to the accelerator's head to reduce the scatter radiation from this source. Results: depending on the geometry of the radiation fields and on the photon energy, a reduction of the dose to the lower abdomen averaged over the depths of 6, 9, and 12 cm from 16% (15 MV, mediastinum case) to 51% (6 MV, cerebrum with additional lead wall) was achieved. The absolute scattered dose with shielding in place for a 2-Gy fraction dose results to 3.85 mGy and 0.27 mGy, respectively. Conclusion: national and international recommendations on the radiation dose to a fetus of a pregnant patient state limits of 200 mSv (DGMP report no. 7) and 100 mGy (ICRP 84), below which an abortion should not be considered and above which an indication for termination of the pregnancy could be given, respectively. The dose to the fetus can be kept below these limits with the shielding described in this work. Therefore, a radiation therapy of a pregnant patient is possible when these special precautions to reduce

  16. JANE, A new information retrieval system for the Radiation Shielding Information Center

    Energy Technology Data Exchange (ETDEWEB)

    Trubey, D.K.

    1991-05-01

    A new information storage and retrieval system has been developed for the Radiation Shielding Information Center (RSIC) at Oak Ridge National Laboratory to replace mainframe systems that have become obsolete. The database contains citations and abstracts of literature which were selected by RSIC analysts and indexed with terms from a controlled vocabulary. The database, begun in 1963, has been maintained continuously since that time. The new system, called JANE, incorporates automatic indexing techniques and on-line retrieval using the RSIC Data General Eclipse MV/4000 minicomputer, Automatic indexing and retrieval techniques based on fuzzy-set theory allow the presentation of results in order of Retrieval Status Value. The fuzzy-set membership function depends on term frequency in the titles and abstracts and on Term Discrimination Values which indicate the resolving power of the individual terms. These values are determined by the Cover Coefficient method. The use of a commercial database base to store and retrieve the indexing information permits rapid retrieval of the stored documents. Comparisons of the new and presently-used systems for actual searches of the literature indicate that it is practical to replace the mainframe systems with a minicomputer system similar to the present version of JANE. 18 refs., 10 figs.

  17. ARES: A Parallel Discrete Ordinates Transport Code for Radiation Shielding Applications and Reactor Physics Analysis

    Directory of Open Access Journals (Sweden)

    Yixue Chen

    2017-01-01

    Full Text Available ARES is a multidimensional parallel discrete ordinates particle transport code with arbitrary order anisotropic scattering. It can be applied to a wide variety of radiation shielding calculations and reactor physics analysis. ARES uses state-of-the-art solution methods to obtain accurate solutions to the linear Boltzmann transport equation. A multigroup discretization is applied in energy. The code allows multiple spatial discretization schemes and solution methodologies. ARES currently provides diamond difference with or without linear-zero flux fixup, theta weighted, directional theta weighted, exponential directional weighted, and linear discontinuous finite element spatial differencing schemes. Discrete ordinates differencing in angle and spherical harmonics expansion of the scattering source are adopted. First collision source method is used to eliminate or mitigate the ray effects. Traditional source iteration and Krylov iterative method preconditioned with diffusion synthetic acceleration are applied to solve the linear system of equations. ARES uses the Koch-Baker-Alcouffe parallel sweep algorithm to obtain high parallel efficiency. Verification and validation for the ARES transport code system have been done by lots of benchmarks. In this paper, ARES solutions to the HBR-2 benchmark and C5G7 benchmarks are in excellent agreement with published results. Numerical results are presented which demonstrate the accuracy and efficiency of these methods.

  18. Study of some health physics parameters of bismuth-ground granulated blast furnace slag shielding concretes

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sandeep, E-mail: sandeep0078monu@gmail.com [Department of Physics, Punjabi University, Patiala (India); Singh, Sukhpal, E-mail: sukhpal-78@rediffmail.com [Department of Basic and Applied Sciences, Punjabi University, Patiala (India)

    2016-05-06

    The Bismuth-ground granulated blastfurnace slang (Bi-GGBFS) concrete samples were prepared. The weight percentage of different elements present in Bi-GGBFS Shielding concretewas evaluated by Energy Dispersive X-ray Microanalysis (EDX). The exposure rate and absorbed dose rate characteristics were calculated theoretically for radioactive sources namely {sup 241}Am and {sup 137}Cs. Our calculations reveal that the Bi-GGBFS concretes are effective in shielding material for gamma radiations.

  19. Male and Female Human Body Tissue Radiation Shielding Models Based upon CT-scan Data for Organ Dose Prediction

    Science.gov (United States)

    Qualls, G.; Nealy, J.; Wilson, J.; Cucinotta, F.

    As present and future human space mission lengths are extended, it becomes increasingly important and valuable to have accurate analytic predictions of radiation doses to specific tissues within the body. New computational models are being developed to help predict the effective radiation shielding to points inside the human body provided by the surrounding body tissue. A female body tissue model, based upon a full-body CT-scan from the Visible Human Project, is presented along with a male body tissue model based upon a full-body CT-scan data set obtained from Johns Hopkins University. The advantages of using CT-scan based models are presented along with initial results and comparisons to previous models. Details of the data processing required to transform a raw CT-scan into a tissue shielding model are also presented.

  20. Elementary computation of radiation doses and shieldings for radiochemical laboratories; Calculo Elemental de dosis y blindajes para laboratorios radioquimicos

    Energy Technology Data Exchange (ETDEWEB)

    Jimeno de Osso, F.

    1971-07-01

    Simple procedures for the calculation of radiation exposition, half thickness, shield thickness, etc. are described and equations and graphs are included for those gamma-emitting radionuclides, that are more often used in radiochemical laboratories. Application is made of these procedures to three radionuclides, bromine-82, sodium-24 and cobalt-60 which cover a rather wl.de energy range; theoretical results are compared with those obtained from experimental measurements. (Author) 23 refs.

  1. A study of shielding properties of x-ray and gamma in barium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Seenappa, L.; Manjunatha, H. C. [Dept. of of Physics, Government College for women, Karnataka (India); Chandrika, B. M. [PC Extension, St. Annes School, Karnataka (India); Chikka, Hanumantharayappa [Vivekananda Degree College, Karnataka (India)

    2017-03-15

    Ionizing radiation is known to be harmful to human health. The shielding of ionizing radiation depends on the attenuation which can be achieved by three main rules, i.e. time, distance and absorbing material. The mass attenuation coefficient, linear attenuation coefficient, Half Value Layer (HVL) and Tenth Value Layer (TVL) of X-rays (32 keV, 74 keV) and gamma rays (662 keV) are measured in Barium compounds. The measured values agree well with the theory. The effective atomic numbers (Z{sub eff}) and electron density (Ne) of Barium compounds have been computed in the wide energy region 1 keV to 100 GeV using an accurate database of photon-interaction cross sections and the WinXCom program. The mass attenuation coefficient and linear attenuation coefficient for BaCO{sub 3} is higher than the BaCl{sub 2}, Ba(No{sub 3}){sub 2} and BaSO{sub 4}. HVL, TVL and mean free path are lower for BaCO{sub 3} than the BaCl{sub 2}, Ba(No{sub 3}){sub 2} and BaSO{sub 4}. Among the studied barium compounds, BaCO{sub 3} is best material for x-ray and gamma shielding.

  2. Shielding optimization studies for the detector systems of the Superconducting Super Collider

    Energy Technology Data Exchange (ETDEWEB)

    Slater, C.O.; Lillie, R.A.; Gabriel, T.A.

    1994-09-01

    Preliminary shielding optimization studies for the Superconducting Super Collider`s Solenoidal Detector Collaboration detector system were performed at the Oak Ridge National Laboratory in 1993. The objective of the study was to reduce the neutron and gamma-ray fluxes leaving the shield to a level that resulted in insignificant effects on the functionality of the detector system. Steel and two types of concrete were considered as components of the shield, and the shield was optimized according to thickness, weight, and cost. Significant differences in the thicknesses, weights, and costs were noted for the three optimization parameters. Results from the study are presented.

  3. Reducing radiation dose to the female breast during CT coronary angiography: A simulation study comparing breast shielding, angular tube current modulation, reduced kV, and partial angle protocols using an unknown-location signal-detectability metric

    Energy Technology Data Exchange (ETDEWEB)

    Rupcich, Franco; Gilat Schmidt, Taly [Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53233 (United States); Badal, Andreu; Popescu, Lucretiu M.; Kyprianou, Iacovos [Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland 20905 (United States)

    2013-08-15

    Purpose: The authors compared the performance of five protocols intended to reduce dose to the breast during computed tomography (CT) coronary angiography scans using a model observer unknown-location signal-detectability metric.Methods: The authors simulated CT images of an anthropomorphic female thorax phantom for a 120 kV reference protocol and five “dose reduction” protocols intended to reduce dose to the breast: 120 kV partial angle (posteriorly centered), 120 kV tube-current modulated (TCM), 120 kV with shielded breasts, 80 kV, and 80 kV partial angle (posteriorly centered). Two image quality tasks were investigated: the detection and localization of 4-mm, 3.25 mg/ml and 1-mm, 6.0 mg/ml iodine contrast signals randomly located in the heart region. For each protocol, the authors plotted the signal detectability, as quantified by the area under the exponentially transformed free response characteristic curve estimator (A-caret{sub FE}), as well as noise and contrast-to-noise ratio (CNR) versus breast and lung dose. In addition, the authors quantified each protocol's dose performance as the percent difference in dose relative to the reference protocol achieved while maintaining equivalent A-caret{sub FE}.Results: For the 4-mm signal-size task, the 80 kV full scan and 80 kV partial angle protocols decreased dose to the breast (80.5% and 85.3%, respectively) and lung (80.5% and 76.7%, respectively) with A-caret{sub FE} = 0.96, but also resulted in an approximate three-fold increase in image noise. The 120 kV partial protocol reduced dose to the breast (17.6%) at the expense of increased lung dose (25.3%). The TCM algorithm decreased dose to the breast (6.0%) and lung (10.4%). Breast shielding increased breast dose (67.8%) and lung dose (103.4%). The 80 kV and 80 kV partial protocols demonstrated greater dose reductions for the 4-mm task than for the 1-mm task, and the shielded protocol showed a larger increase in dose for the 4-mm task than for the 1-mm

  4. NEUTRONIC REACTOR SHIELD

    Science.gov (United States)

    Fermi, E.; Zinn, W.H.

    1957-09-24

    The reactor radiation shield material is comprised of alternate layers of iron-containing material and compressed cellulosic material, such as masonite. The shielding material may be prefabricated in the form of blocks, which can be stacked together in ary desired fashion to form an effective shield.

  5. Modeling of neutron and photon transport in iron and concrete radiation shields by using Monte Carlo method

    CERN Document Server

    Žukauskaitėa, A; Plukienė, R; Ridikas, D

    2007-01-01

    Particle accelerators and other high energy facilities produce penetrating ionizing radiation (neutrons and γ-rays) that must be shielded. The objective of this work was to model photon and neutron transport in various materials, usually used as shielding, such as concrete, iron or graphite. Monte Carlo method allows obtaining answers by simulating individual particles and recording some aspects of their average behavior. In this work several nuclear experiments were modeled: AVF 65 (AVF cyclotron of Research Center of Nuclear Physics, Osaka University, Japan) – γ-ray beams (1-10 MeV), HIMAC (heavy-ion synchrotron of the National Institute of Radiological Sciences in Chiba, Japan) and ISIS-800 (ISIS intensive spallation neutron source facility of the Rutherford Appleton laboratory, UK) – high energy neutron (20-800 MeV) transport in iron and concrete. The calculation results were then compared with experimental data.compared with experimental data.

  6. Hybrid Wing Body Shielding Studies Using an Ultrasonic Configurable Fan Artificial Noise Source Generating Simple Modes

    Science.gov (United States)

    Sutliff, Daniel, L.; Brown, Clifford, A.; Walker, Bruce, E.

    2012-01-01

    An Ultrasonic Configurable Fan Artificial Noise Source (UCFANS) was designed, built, and tested in support of the Langley Research Center s 14- by 22-Foot wind tunnel test of the Hybrid Wing Body (HWB) full three-dimensional 5.8 percent scale model. The UCFANS is a 5.8 percent rapid prototype scale model of a high-bypass turbofan engine that can generate the tonal signature of candidate engines using artificial sources (no flow). The purpose of the test was to provide an estimate of the acoustic shielding benefits possible from mounting the engine on the upper surface of an HWB aircraft and to provide a database for shielding code validation. A range of frequencies, and a parametric study of modes were generated from exhaust and inlet nacelle configurations. Radiated acoustic data were acquired from a traversing linear array of 13 microphones, spanning 36 in. Two planes perpendicular to the axis of the nacelle (in its 0 orientation) and three planes parallel were acquired from the array sweep. In each plane the linear array traversed five sweeps, for a total span of 160 in. acquired. The resolution of the sweep is variable, so that points closer to the model are taken at a higher resolution. Contour plots of Sound Pressure Level, and integrated Power Levels are presented in this paper; as well as the in-duct modal structure.

  7. iSHIELD - A Line Source Application of SHIELD11

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, W.R.; Rokni, S.H.; /SLAC

    2006-04-27

    iSHIELD11 performs a line-source numerical integration of radiation source terms that are defined by the iSHIELD11 computer code[1] . An example is provided to demonstrate how one can use iSHIELD11 to perform a shielding analysis for a 250 GeV electron linear accelerator.

  8. First-principles investigation on solar radiation shielding performance of rutile VO2 filters for smart windows

    Science.gov (United States)

    Xiao, Lihua; Su, Yuchang; Qiu, Wei; Ran, Jingyu; Liu, Yike; Wu, Jianming; Lu, Fanghai; Shao, Fang; Peng, Ping

    2016-11-01

    Vanadium dioxide (VO2) undergoing reversible metal-insulator phase transition could allow for the formation of an efficient thermochromic material for smart windows. However, solar radiation shielding performance is determined by transparent rutile VO2 filters, and the puzzling metal-insulator transition mechanism makes it challenging to explain the origin of the coexistence of strong near infrared absorption with high optical transparency. The band structure, the density of states, and the optical properties of rutile VO2 were calculated using the first-principles calculations. The calculated results of the structural and optical properties are in good agreement with the previously reported experimental findings. The calculated dielectric functions, electron energy-loss function and solar radiation shielding performance of the rutile VO2 filters indicate that rutile VO2 is a promising near-infrared absorption/reflectance material with the near-infrared radiation insulating abilities and a visible light transmittance. These properties arise from plasma oscillation and a collective oscillation (volume plasmons) of carrier electrons.

  9. Exposure Buildup Factors for Heavy Metal Oxide Glass: A Radiation Shield

    DEFF Research Database (Denmark)

    Manonara, S. R.; Hanagodimath, S. M.; Gerward, Leif

    2011-01-01

    Gamma ray exposure buildup factors for three Heavy Metal Oxide (HMO) glass systems, viz. PbO-Bi2O3-B2O3, PbO-B2O3, and Bi2O3-B2O3 glasses are presented. The computations were done by interpolation method using the Geometric Progression fitting formula and ANSI/ANS-6.4.3 library for the energy range...... of graphs. Buildup factors of these HMO glasses cannot be found in any standard database, but they are useful for practical calculations in gamma ray shield designs, and they also, help to determine and control the thickness of the shielding material used....

  10. A comparison of dose savings of lead and lightweight aprons for shielding of 99m-Technetium radiation.

    Science.gov (United States)

    Warren-Forward, Helen; Cardew, Paul; Smith, Bradley; Clack, Llewellyn; McWhirter, Kym; Johnson, Stacey; Wessel, Kimberly

    2007-01-01

    Nuclear medicine technologists (NMTs) have the highest effective doses of radiation among medical workers. With increase in the use of lightweight materials in diagnostic radiography, the aim was to compare the effectiveness of lead and lightweight aprons in shielding from 99m-Technetium ((99m)Tc) gamma rays. The doses received from a scattering phantom to the entrance, 9cm depth and exit of a phantom were measured with LiF:Mg, Cu, P thermoluminescent dosemeters (TLDs). Doses and spectra were assessed without no shielding, with 0.5-mm lead and lightweight aprons. The lead and lightweight aprons decreased entrance surface doses by 76 and 59%, respectively. The spectral analysis showed that the lightweight apron provided better dose reduction at energies lead was 35% more efficient at higher energies. While lead apron demonstrated better shielding, the additional savings should be considered with the weight differential. It is concluded that the lightweight apron is suitable to be worn by NMTs interacting with patients injected with a (99m)Tc labelled radiopharmaceutical.

  11. Zone 4 Study: Shielded Lift Truck Refurbishment/Replacement

    Energy Technology Data Exchange (ETDEWEB)

    AMAI, WENDY A.; JONES, JAMES F.; LENNOX, R. CHARLEENE; SIMON, RONALD W.; JONES, JAMES F

    2002-09-01

    The Zone 4 Stage Right Shielded Lift Trucks (SLT's) will likely need refurbishment or replacement within the next two to five years, due to wear. This document discusses the options to provide a long term and reliable means of satisfying Zone 4 material movement and inventory requirements.

  12. On the use of Indium ({sup 115}In) activation foils for the study of neutron radiation field surrounding a not shielded cyclotron; Sobre o uso de folhas de ativacao de Indio ({sup 115}In) para o estudo do campo de radiacao neutronica ao redor de um ciclotron nao blindado

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Adriana, E-mail: amgr@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Programa de Pos-Graduacao em Ciencia e Tecnologia das Radiacoes, Minerais e Materiais; Rodrigues, Sergio Luiz Moreira; Andrade, Ricardo Severino [Centro de Desenvolvimento da Tecnologia Nuclear (SECPRA/CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico de Pesquisa e Producao de Radiofarmacos; Lacerda, Marco Aurelio de Sousa [Centro de Desenvolvimento da Tecnologia Nuclear (SEPRA/CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico de Protecao Radiologica; Silva, Teogenes Augusto da [Centro de Desenvolvimento da Tecnologia Nuclear (SERAS/CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico das Radiacoes Aplicadas a Saude

    2011-10-26

    Use activation foils of {sup 115}In were evaluated for study of neutron radiation field surrounding a non shielded 16.5 MeV cyclotron, during the production of fluorine-18. Two foils of {sup 115}In were used which were exposed to the neutron flux of target-chamber of the GEPETtrace-8 of CDTN/CNEN, Brazil. The first foil were positioned in front of cyclotron beam, and the second one in the diametral opposed position to the beam. It was possible to distinguish for the first foil the 417 keV photo peaks, attributed to the thermal and the 417 keV neutrons attributed to the fast neutrons. On the second foil it was only distinguished the 417 keV photopeak. The results had shown that it is possible to evaluate the fast and thermal neutron fraction surrounding the cyclotron by using indium foils. However, the short half life of the {sup 115}In makes unviable the simultaneous irradiation of a great number of foils

  13. Study of the shielding for spontaneous fission sources of Californium-252; Estudio de blindaje para fuentes de fision espontanea de Californio-252

    Energy Technology Data Exchange (ETDEWEB)

    Davila R, I

    1991-06-15

    A shielding study is made to attenuate, until maximum permissible levels, the neutrons radiation and photons emitted by spontaneous fission coming from a source of Californium-252. The compound package by a database (Library DLC-23) and the ANISNW code is used, in it version for personal computer. (Author)

  14. Shielding biomolecules from effects of radiation by Mars analogue minerals and soils

    Science.gov (United States)

    Ertem, G.; Ertem, M. C.; McKay, C. P.; Hazen, R. M.

    2017-07-01

    Organic compounds have been delivered over time to Mars via meteorites, comets and interplanetary dust particles. The fate of organic material on the surface of Mars must be affected by the Martian environment, in particular by ultraviolet (UV) and other ionizing radiation. Penetration depth of UV radiation into soils is in the sub-millimetre to millimetre range and depends on the properties of the soil. The aim of this research is to study the possible protective role of Martian analogue minerals and soils for survivability of biomolecules against UV radiation and to compare their decomposition rates within a 1 mm-thick portion of the surface. Results demonstrated that minerals offer significant protection to biomolecules purine, pyrimidine and uracil against UV photolysis. In the absence of these minerals, organic compounds are completely degraded when subjected directly to UV photolysis equivalent to only 5 Martian day's exposure. However, similar UV exposure of organics dried from solution onto powdered calcium carbonate (calcite; CaCO3), calcium sulphate (anhydrite; CaSO4), clay-bearing Atacama dessert soil and 7 Å clay mineral kaolinite [Al2Si2O5(OH)4] results in only 1-2% loss of organics. Mixtures of purine and uracil with calcium carbonate exposed to gamma radiation of 3 Gy (3 Gray), which corresponds to approximately 15 000 days on Mars, results in up to 10% loss of organics. By contrast, these organic compounds completely decomposed upon mixing with iron oxide (Fe2O3) before UV irradiation. As the search for extinct or extant life on Mars has been identified as a goal of top priority in NASA's Mars Exploration Program and continues with several missions planned to the red planet by both NASA and the European Space Agency (ESA) in the next few decades, our findings may play a useful role in identifying optimal target sites on the Martian surface for future missions.

  15. Development of epoxy resin-type neutron shielding materials (I)

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Soo Haeng; Kim, Ik Soo; Shin, Young Joon; Do, Jae Bum; Ro, Seung Gy

    1997-12-01

    Because the exposure to radiation in the nuclear facilities can be fatal to human, it is important to reduce the radiation dose level to a tolerable level. The purpose of this study is to develop highly effective neutron shielding materials for the shipping and storage cask of radioactive materials or in the nuclear /radiation facilities. On this study, we developed epoxy resin based neutron shielding materials and their various materials properties, including neutron shielding ability, fire resistance, combustion characteristics, radiation resistance, thermal and mechanical properties were evaluated experimentally. (author). 31 refs., 22 tabs., 17 figs.

  16. DWNT/Hydrogenated Fullerene Reinforced Polyethylene for Radiation Shielding Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Manned space exploration requires radiation protection, particularly since the impact of radiation on the health and safety of humans on extended missions is not...

  17. Lightweight Shield Against Space Debris

    Science.gov (United States)

    Redmon, John W., Jr.; Lawson, Bobby E.; Miller, Andre E.; Cobb, W. E.

    1992-01-01

    Report presents concept for lightweight, deployable shield protecting orbiting spacecraft against meteoroids and debris, and functions as barrier to conductive and radiative losses of heat. Shield made in four segments providing 360 degree coverage of cylindrical space-station module.

  18. Can active proton interrogation find shielded nuclear threats at human-safe radiation levels?

    Energy Technology Data Exchange (ETDEWEB)

    Liew, Seth Van, E-mail: vanliew@gmail.com

    2017-05-21

    A new method of low-dose proton radiography is presented. The system is composed of an 800 MeV proton source, bending magnets, and compact detectors, and is designed for drive-through cargo scanning. The system has been simulated using GEANT4. Material identification algorithms and pixel sorting methods are presented that allow the system to perform imaging at doses low enough to scan passenger vehicles and people. Results are presented on imaging efficacy of various materials and cluttered cargoes. The identification of shielded nuclear materials at human-safe doses has been demonstrated.

  19. Radiation protection to the eye and thyroid during diagnostic cerebral angiography: a phantom study.

    LENUS (Irish Health Repository)

    Shortt, C P

    2008-08-01

    We measured radiation doses to the eye and thyroid during diagnostic cerebral angiography to assess the effectiveness of bismuth and lead shields at dose reduction. Phantom head angiographic studies were performed with bismuth (study 1) and lead shields (study 2). In study 1 (12 phantoms), thermoluminescent dosimeters (TLD) were placed over the eyes and thyroid in three groups: (i) no shields (four phantoms); (ii) anterior bismuth shields (four phantoms) and (iii) anterior and posterior bismuth shields (four phantoms). In a second study (eight phantoms), lead shields were placed over the thyroid only and TLD dose measurements obtained in two groups: (i) no shielding (four phantoms) and (ii) thyroid lead shielding (four phantoms). A standard 4-vessel cerebral angiogram was performed on each phantom. Study 1 (bismuth shields) showed higher doses to the eyes compared with thyroid (mean 13.03 vs 5.98 mSv, P < 0.001) and a higher eye dose on the X-ray tube side. Overall, the use of bismuth shielding did not significantly reduce dose to either eyes or thyroid in the measured TLD positions. In study 2, a significant thyroid dose reduction was found with the use of lead shields (47%, mean 2.46 vs 4.62 mSv, P < 0.001). Considerable doses to the eyes and thyroid highlight the need for increased awareness of patient protection. Eye shielding is impractical and interferes with diagnostic capability. Thyroid lead shielding yields significant protection to the thyroid, is not in the field of view and should be used routinely.

  20. Evaluation of Personal Shields Used in Selected Radiology Departments

    Directory of Open Access Journals (Sweden)

    Mohsen Salmanvandi

    2015-05-01

    Full Text Available Introduction The purpose of this study was to evaluate personal shields in radiation departments of hospitals affiliated to Mashhad University of Medical Sciences. Materials and Methods First, the information related to 109 personal shields was recorded and evaluated by imaging equipment. Afterwards, the equivalent lead thickness (ELT of 62 personal shields was assessed, using dosimeter and standard lead layers at 100 kVp. Results In this study, 109 personal shields were assessed in terms of tears, holes and cracks. The results showed that 18 shields were damaged. Moreover, ELT was evaluated in 62 shields. As the results indicated, ELT was unacceptable in 8 personal shields and lower than expected in 9 shields. Conclusion According to the results, 16.5% of personal shields had defects (tears, holes and cracks and 13% of them were unacceptable in terms of ELT and needed to be replaced. Therefore, regular quality control of personal shields and evaluation of new shields are necessary at any radiation department.

  1. Evaluation of radiation shielding performance in sea transport of radioactive material by using simple calculation method

    Energy Technology Data Exchange (ETDEWEB)

    Odano, N.; Ohnishi, S. [National Maritime Research Inst., Tokyo (Japan); Sawamura, H.; Tanaka, Y.; Nishimura, K. [Computer Software Development Co. Ltd., Tokyo (Japan)

    2004-07-01

    A modified code system based on the point kernel method was developed to use in evaluation of shielding performance for maritime transport of radioactive material. For evaluation of shielding performance accurately in the case of accident, it is required to preciously model the structure of transport casks and shipping vessel, and source term. To achieve accurate modelling of the geometry and source term condition, we aimed to develop the code system by using equivalent information regarding structure and source term used in the Monte Carlo calculation code, MCNP. Therefore, adding an option to use point kernel method to the existing Monte Carlo code, MCNP4C, the code system was developed. To verify the developed code system, dose rate distribution in an exclusive shipping vessel to transport the low level radioactive wastes were calculated by the developed code and the calculated results were compared with measurements and Monte Carlo calculations. It was confirmed that the developed simple calculation method can obtain calculation results very quickly with enough accuracy comparing with the Monte Carlo calculation code MCNP4C.

  2. Optimization of a partially non-magnetic primary radiation shielding for the triple-axis spectrometer PANDA at the Munich high-flux reactor FRM-II

    CERN Document Server

    Pyka, N M; Rogov, A

    2002-01-01

    Monte Carlo simulations have been used to optimize the monochromator shielding of the polarized cold-neutron triple-axis spectrometer PANDA at the Munich high-flux reactor FRM-II. By using the Monte Carlo program MCNP-4B, the density of the total spectrum of incoming neutrons and gamma radiation from the beam tube SR-2 has been determined during the three-dimensional diffusion process in different types of heavy concrete and other absorbing material. Special attention has been paid to build a compact and highly efficient shielding, partially non-magnetic, with a total biological radiation dose of less than 10 mu Sv/h at its outsides. Especially considered was the construction of an albedo reducer, which serves to reduce the background in the experiment outside the shielding. (orig.)

  3. Gonad Shielding for Patients Undergoing Conventional Radiological Examinations: Is There Cause for Concern?

    Directory of Open Access Journals (Sweden)

    Karami

    2016-04-01

    Full Text Available Background Gonad shielding is one of the fundamental methods by which to protect reproductive organs in patients undergoing conventional radiological examinations. A lack of or inadequate shielding of the gonads may increase the exposure of these organs and result in malignancies future generations. Objectives The aim of this study is to investigate the prevalence of gonad shielding in patients undergoing conventional radiological examinations and the availability of gonad shields and gonad shielding protocols in radiology departments. Materials and Methods A retrospective, observational cross-sectional study on the application of gonad shielding, the availability of gonad shields and the existence of gonad shielding protocols in radiology departments was performed in five different hospitals in Ahvaz, Iran. Results The highest application of gonad shielding was 6.6% for the pediatric hospital. The prevalence of gonad shielding was less than 0.2%. In 64.3% of the radiography rooms, at least one flat-contact gonad shield of a large size was available. Only large-sized gonad shields were available. Curved-contact and shadow gonad shields did not exist. Gonad shielding protocols were not existence in any of the fourteen radiography rooms investigated. Conclusions Comprehensive protection programs with on-the-job training courses for staff members are strongly recommended, as well as, the provision of radiological shields and gonad shielding protocols in radiology departments to reduce the patient’s radiation dose during radiological examinations.

  4. Compton scattering by internal shields based on melanin-containing mushrooms provides protection of gastrointestinal tract from ionizing radiation.

    Science.gov (United States)

    Revskaya, Ekaterina; Chu, Peter; Howell, Robertha C; Schweitzer, Andrew D; Bryan, Ruth A; Harris, Matthew; Gerfen, Gary; Jiang, Zewei; Jandl, Thomas; Kim, Kami; Ting, Li-Min; Sellers, Rani S; Dadachova, Ekaterina; Casadevall, Arturo

    2012-11-01

    There is a need for radioprotectors that protect normal tissues from ionizing radiation in patients receiving high doses of radiation and during nuclear emergencies. We investigated the possibility of creating an efficient oral radioprotector based on the natural pigment melanin that would act as an internal shield and protect the tissues via Compton scattering followed by free radical scavenging. CD-1 mice were fed melanin-containing black edible mushrooms Auricularia auricila-judae before 9 Gy total body irradiation. The location of the mushrooms in the body before irradiation was determined by in vivo fluorescent imaging. Black mushrooms protected 80% of mice from the lethal dose, while control mice or those given melanin-devoid mushrooms died from gastrointestinal syndrome. The crypts of mice given black mushrooms showed less apoptosis and more cell division than those in control mice, and their white blood cell and platelet counts were restored at 45 days to preradiation levels. The role of melanin in radioprotection was proven by the fact that mice given white mushrooms supplemented with melanin survived at the same rate as mice given black mushrooms. The ability of melanin-containing mushrooms to provide remarkable protection against radiation suggests that they could be developed into oral radioprotectors.

  5. Evaluation of syringe shield effectiveness in handling radiopharmaceuticals

    Directory of Open Access Journals (Sweden)

    Cho Yong-In

    2015-01-01

    Full Text Available The purpose of this study was to evaluate the effectiveness of the radiation shield of radionuclide syringes and the personal dose equivalent by performing a simulation of radionuclides used in nuclear medicine diagnosis. In order to evaluate the dose depending on the distance between the radiation source and the ICRU sphere against the thickness of the shielding device, the distance at which a nuclear medicine worker may inadvertently come into contact with radiation from the radiation source was set at 0 cm to 30 cm according to the thickness of the shield, thus fixing the ICRU sphere. For a dose evaluation, Hp(10, Hp(3, and Hp(0.07 measurable in specific depth of the ICRU were evaluated. It was found that a dose measured on skin surface of nuclear medicine workers was relatively higher, that the dose varied in relation to the thickness of the radiation shield, and that the shielding effect decreased for some radiation sources such as 67Ga and 111In. It proved necessary to increase thickness of shielding device to the radiation sources such as 67Ga and 111In. It is also considered that a study of proper shielding thickness will be needed in future.

  6. Electrodynamic Dust Shield Technology for Thermal Radiators Used in Lunar Exploration

    Science.gov (United States)

    Calle, Carlos I.; Hogue, Michael D.; Snyder, Sarah J.; Clements, Sidney J.; Johansen, Michael R.; Chen, Albert

    2011-01-01

    Two general types of thermal radiators are being considered for lunar missions: coated metallic surfaces and Second Surface Mirrors. Metallic surfaces are coated with a specially formulated white paint that withstands the space environment and adheres well to aluminium, the most common metal used in space hardware. AZ-93 White Thermal Control Paint, developed for the space program, is an electrically conductive inorganic coating that offers thermal control for spacecraft. It is currently in use on satellite surfaces (Fig 1). This paint withstands exposure to atomic oxygen, charged particle radiation, and vacuum ultraviolet radiation form 118 nm to 170 nm while reflecting 84 to 85% of the incident solar radiation and emitting 89-93% of the internal heat generated inside the spacecraft.

  7. Foundation, excavation and radiation shielding concepts for a 16-m large lunar telescope

    Science.gov (United States)

    Chua, Koon M.; Johnson, Stewart W.

    1991-09-01

    NASA is considering a 16-m diameter optical telescope on the moon as a part of the Space Exploration Initiative. Fundamental concepts of engineering activities on the moon and how they can be applied to the establishment of a 16-m large lunar telescope (LLT) are discussed. These fundamental concepts include the engineering response of lunar soils and how they affect construction activities, namely, drilling, blasting, ripping, digging and compaction. A mirror support structure and foundation design concept is proposed. The foundation considered is a multiple contact points spud-can type footing. It does not appear that a deep foundation or the presence of bedrock is required to achieve the telescope foundation stiffness. The LLT system will include a regolith covered housing, the size of a small room, which will contain sensitive electronic equipment including charge coupled devices which need protection from cosmic radiation effects. A brief discussion is made on radiation, radiation transport and radiation effects on electronics and on humans. Radiation protection techniques and the different emplacement schemes for the LLT instrument housing for radiation protection are suggested. A structural concept of an early lunar based telescope is also presented.

  8. Foundation, excavation and radiation shielding concepts for a 16-m large lunar telescope

    Science.gov (United States)

    Chua, Koon M.; Johnson, Stewart W.

    1991-01-01

    NASA is considering a 16-m diameter optical telescope on the moon as a part of the Space Exploration Initiative. Fundamental concepts of engineering activities on the moon and how they can be applied to the establishment of a 16-m large lunar telescope (LLT) are discussed. These fundamental concepts include the engineering response of lunar soils and how they affect construction activities, namely, drilling, blasting, ripping, digging and compaction. A mirror support structure and foundation design concept is proposed. The foundation considered is a multiple contact points spud-can type footing. It does not appear that a deep foundation or the presence of bedrock is required to achieve the telescope foundation stiffness. The LLT system will include a regolith covered housing, the size of a small room, which will contain sensitive electronic equipment including charge coupled devices which need protection from cosmic radiation effects. A brief discussion is made on radiation, radiation transport and radiation effects on electronics and on humans. Radiation protection techniques and the different emplacement schemes for the LLT instrument housing for radiation protection are suggested. A structural concept of an early lunar based telescope is also presented.

  9. Shielding Efficiency of a Fabric Based on Amorphous Glass-Covered Magnetic Microwires to Radiation Emitted by a Mobile Phone in 2G and 3G Communication Technologies

    Directory of Open Access Journals (Sweden)

    Miclăuş Simona

    2017-12-01

    Full Text Available A dual band mobile phone model was used to check the shielding properties of an amorphous ferromagnetic textile against the radiation emitted by the handset. Two frequencies belonging to the 2nd and 3rd generation of mobile emission technologies were used, 897 MHz and 1950 MHz. The specific absorption rate (SAR of energy deposition in a human head phantom was measured in standardized conditions. The textile contained micrometric-diameter wires of a ferromagnetic mixture embedded in a thin glass coat and weaved in a specific way. A set of fabric orientations and configurations (layering were provided in the experiment in order to achieve a better shielding to the phone’s radiation. Compared with the non-shielded handset, SAR deposited in the head while using the fabric-covered phone could be decreased up to 30 % of its initial value – in case of 2G technology and up to 24 % – in case of 3G technology. This type of material shows one of the highest shielding efficiencies of the electric-field component in near-field exposure conditions reported until now. A cubic curve of SAR decrease in depth of the head was revealed in both uncovered and covered handset, the effect of shielding being larger at the higher frequency.

  10. New applications and developments in the neutron shielding

    Science.gov (United States)

    Uğur, Fatma Aysun

    2017-09-01

    Shielding neutrons involve three steps that are slowing neutrons, absorption of neutrons, and impregnation of gamma rays. Neutrons slow down with thermal energy by hydrogen, water, paraffin, plastic. Hydrogenated materials are also very effective for the absorption of neutrons. Gamma rays are produced by neutron (radiation) retention on the neutron shield, inelastic scattering, and degradation of activation products. If a source emits gamma rays at various energies, high-energy gamma rays sometimes specify shielding requirements. Multipurpose Materials for Neutron Shields; Concrete, especially with barium mixed in, can slow and absorb the neutrons, and shield the gamma rays. Plastic with boron is also a good multipurpose shielding material. In this study; new applications and developments in the area of neutron shielding will be discussed in terms of different materials.

  11. Shielding Studies for the CERN Super-Proton-Synchrotron at Experimental Point 5

    CERN Document Server

    Müller, Mario J

    2004-01-01

    The European Laboratory for Particle Research, CERN has been operated the Super Proton Sychrotron (SPS) for more than 30 years with the shielding design knowledge of the early 70s. At that time particle transport codes were neither available nor capable of dealing with deep lateral shielding calculations. For the future LHC increasing projected values of beam intensity in the SPS and decreasing limits to radiation exposure have led to the need to re-assess the shielding at point 5 of the SPS. 20 years ago this area housed the UA1 experiment of Carlo Rubbia (nobel-price 1984). The thesis describes a re-assessment based on simulations using the multi-purpose radiation transport codes FLUKA and MCNPX. The latter one was utilized for geometry design and to compare variance reduction methods. Different assumed beam-loss points along the beam-line together with fluence-to-doserate conversion calculations were used to find the worst case scenario. Dose-rates as well as particle-energy spectra inside the accessible a...

  12. Grounding, shielding, and bonding

    Science.gov (United States)

    Catrysse, J.

    1991-06-01

    In the electromagnetic compatibility design (EMC) of systems and circuits, both grounding and shielding are related to the coupling mechanisms of the system with (radiated) electromagnetic fields. Grounding is more related to the source or victim circuit (or system) and determines the characteristic of the coupling mechanism between fields and currents/voltages. Shielding is a way of interacting in the radiation path of an electromagnetic field. The basic principles and practical design rules are discussed.

  13. Extended one-dimensional method for coherent synchrotron radiation including shielding

    Directory of Open Access Journals (Sweden)

    David Sagan

    2009-04-01

    Full Text Available Coherent synchrotron radiation can severely limit the performance of accelerators designed for high brightness and short bunch length. Examples include light sources based on energy recovery LINAC or free-electron lasers, and bunch compressors for linear colliders. In order to better simulate coherent synchrotron radiation, a one-dimensional formalism due to Saldin, Schneidmiller, and Yurkov has been implemented in the general beam dynamics code Bmad. Wide vacuum chambers are simulated by means of vertical image charges. Results from Bmad are here compared to analytical approximations, to numerical solutions of the Maxwell equations, and to the simulation code elegant and the code of Agoh and Yokoya.

  14. ERA's Open Rotor Studies Including Shielding for Noise Reduction

    Science.gov (United States)

    Van Zante, Dale; Thomas, Russell

    2012-01-01

    The Open Rotor is a modern version of the UnDucted Fan (UDF) that was flight tested in the late 1980's through a partnership between NASA and General Electric (GE). Tests were conducted in the 9' x 15' Low Speed Wind Tunnel and the 8' x 6' Supersonic Wind Tunnel starting in late 2009 and completed in early 2012. Aerodynamic and acoustic data were obtained for takeoff, approach and cruise simulations. GE was the primary partner, but other organizations were involved such as Boeing and Airbus who provided additional hardware for fuselage simulations. This test campaign provided the acoustic and performance characteristics for modern open rotor blades designs." NASA and GE conducted joint systems analysis to evaluate how well new blade designs would perform on a B737 class aircraft, and compared the results to an advanced higher bypass ratio turbofan." Acoustic shielding experiments were performed at NASA GRC and Boeing LSAF facilities to provide data for noise estimates of unconventional aircraft configurations with Open Rotor propulsion systems." The work was sponsored by NASA's aeronautics programs, including the Subsonic Fixed Wing (SFW) and the Environmentally Responsible Aviation (ERA) projects."

  15. Study of casks shielded with heavy metal to transport highly radioactive substances; Estudo de embalados com blindagem em metal pesado para transporte de substancias altamente radioativas

    Energy Technology Data Exchange (ETDEWEB)

    Lucchesi, R.F.; Hara, D.H.S.; Martinez, L.G.; Mucsi, C.S.; Rossi, J.L., E-mail: rflguimaraes@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2014-07-01

    Nowadays, Brazil relies on casks produced abroad for transportation in its territory of substances that are sources of high radioactivity, especially the Mo-99. The product of the radioactive decay of the Mo-99 is the Tc-99m, which is used in nuclear medicine for administration to humans in the form of injectable radioactive drugs for the image diagnosis of numerous pathologies. This paper aims to study the existing casks in order to propose materials for the construction of the core part as shielding against gamma radiation. To this purpose, the existing literature on the subject was studied, as well as evaluation of existing and available casks. The study was focused on the core of which is made of heavy metals, especially depleted uranium for shielding the emitted radiation. (author)

  16. Study on the Shielding Effectiveness of an Arc Thermal Metal Spraying Method against an Electromagnetic Pulse

    Directory of Open Access Journals (Sweden)

    Han-Seung Lee

    2017-10-01

    Full Text Available An electromagnetic pulse (EMP explodes in real-time and causes critical damage within a short period to not only electric devices, but also to national infrastructures. In terms of EMP shielding rooms, metal plate has been used due to its excellent shielding effectiveness (SE. However, it has difficulties in manufacturing, as the fabrication of welded parts of metal plates and the cost of construction are non-economical. The objective of this study is to examine the applicability of the arc thermal metal spraying (ATMS method as a new EMP shielding method to replace metal plate. The experimental parameters, metal types (Cu, Zn-Al, and coating thickness (100–700 μm used for the ATMS method were considered. As an experiment, a SE test against an EMP in the range of 103 to 1010 Hz was conducted. Results showed that the ATMS coating with Zn-Al had similar shielding performance in comparison with metal plate. In conclusion, the ATMS method is judged to have a high possibility of actual application as a new EMP shielding material.

  17. Radiochromic film for dosimetric measurements in radiation shielding composites synthesized for applied in radiology procedures of high dose

    Energy Technology Data Exchange (ETDEWEB)

    Fontainha, C. C. P. [Universidade Federal de Minas Gerais, Departamento de Engenharia Nuclear, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil); Baptista N, A. T.; Faria, L. O., E-mail: crissia@gmail.com [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2015-10-15

    Full text: Medical radiology offers great benefit to patients. However, although specifics procedures of high dose, as fluoroscopy, Interventional Radiology, Computed Tomography (CT) make up a small percent of the imaging procedures, they contribute to significantly increase dose to population. The patients may suffer tissue damage. The probability of deterministic effects incidence depends on the type of procedure performed, exposure time, and the amount of applied dose at the irradiated area. Calibrated radiochromic films can identify size and distribution of the radiated fields and measure intensities of doses. Radiochromic films are sensitive for doses ranging from 0.1 to 20 c Gy and they have the same response for X-rays effective energies ranging from 20 to 100 keV. New radiation attenuators materials have been widely investigated resulting in dose reduction entrance skin dose. In this work, Bi{sub 2}O{sub 3} and ZrO{sub 2}:8 % Y{sub 2}O{sub 3} composites were obtained by mixing them with P(VDF-Tr Fe) copolymers matrix from casting method and then characterized by Ftir. Dosimetric measurements were obtained with Xr-Q A2 Gafchromic radiochromic films. In this setup, one radiochromic film is directly exposed to the X-rays beam and another one measures the attenuated beam were exposed to an absorbed dose of 10 mGy of RQR5 beam quality (70 kV X-ray beam). Under the same conditions, irradiated Xr-Q A2 films were stored and scanned measurement in order to obtain a more reliable result. The attenuation factors, evaluated by Xr-Q A2 radiochromic films, indicate that both composites are good candidates for use as patient radiation shielding in high dose medical procedures. (Author)

  18. Shadow Radiation Shield Required Thickness Estimation for Space Nuclear Power Units

    Science.gov (United States)

    Voevodina, E. V.; Martishin, V. M.; Ivanovsky, V. A.; Prasolova, N. O.

    The paper concerns theoretical possibility of visiting orbital transport vehicles based on nuclear power unit and electric propulsion system on the Earth's orbit by astronauts to maintain work with payload from the perspective of radiation safety. There has been done estimation of possible time of the crew's staying in the area of payload of orbital transport vehicles for different reactor powers, which is a consistent part of nuclear power unit.

  19. Effect of Flyash Addition on Mechanical and Gamma Radiation Shielding Properties of Concrete

    Directory of Open Access Journals (Sweden)

    Kanwaldeep Singh

    2014-01-01

    Full Text Available Six concrete mixtures were prepared with 0%, 20%, 30%, 40%, 50%, and 60% of flyash replacing the cement content and having constant water to cement ratio. The testing specimens were casted and their mechanical parameters were tested experimentally in accordance with the Indian standards. Results of mechanical parameters show their improvement with age of the specimens and results of radiation parameters show no significant effect of flyash substitution on mass attenuation coefficient.

  20. The Study of the Electromagnetic Shielding Properties of a Textile Material with Amorphous Microwire

    Directory of Open Access Journals (Sweden)

    RAU, M.

    2011-02-01

    Full Text Available The paper presents the results concerning the utilization of a new class of composite textile materials with electromagnetic properties and the possibility of their utilization in the production of electromagnetic field protective equipment. The experimental and theoretical results concerning the electromagnetic characterization of a new textile material with composite structure are presented also considering the following aspects: - evaluation of the possibilities to use amorphous magnetic microwires in electromagnetic shielding; - study of the electromagnetic properties of the composite textile material, especially the electromagnetic field shielding, reflection and polarization; - determination of the frequency range within which these properties can be used in the realization of materials for the protection against electromagnetic fields. The experimental results of a material sample and a phantom for applications are connected with shielding in the frequency range used in mobile communications.

  1. Determination of total mass attenuation coefficients, effective atomic numbers and electron densities for different shielding materials used in radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Almeida J, A. T. [FUNDACENTRO, Centro Regional de Minas Gerais, Brazilian Institute for Safety and Health at Work, Belo Horizonte, 30180-100 Minas Gerais (Brazil); Nogueira, M. S. [Center of Development of Nuclear Technology / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil); Santos, M. A. P., E-mail: mnogue@cdtn.br [Regional Center for Nuclear Science / CNEN, 50.740-540 Recife, Pernambuco (Brazil)

    2015-10-15

    Full text: In this paper, the interaction of X-rays with some shielding materials has been studied for materials containing different amounts of barite and aggregates. The total mass attenuation coefficient (μ{sub t}) for three shielding materials has been calculated by using WinXCOM program in the energy range from RQR qualities (RQR-4, RQR-6, RQR-9, and RQR-10). They were: cream barite (density 2.99 g/cm{sup 3} collected in the State of Sao Paulo), purple barite (density 2.95 g/cm{sup 3} collected in the State of Bahia) and white barite (density 3.10 g/cm{sup 3} collected in the State of Paraiba). The chemical analysis was carried out by an X-ray fluorescence spectrometer model EDX-720, through dispersive energy. The six elements of the higher concentration found in the sample and analyzed by Spectrophotometry of Energy Dispersive X-ray for the samples were Ba(60.9% - white barite), Ca(17,92% - cream barite), Ce(3,60% - white barite), Fe(17,16% - purple barite), S(12,11% - white barite) and Si(29,61% - purple barite). Also, the effective atomic number (Z{sub eff}) and the effective electron density (N{sub eff}) were calculated using the values of the total mass attenuation coefficient. The dependence of these parameters on the incident photon energy and the chemical composition has been examined. (Author)

  2. Safety analysis and lay-out aspects of shieldings against particle radiation at the example of spallation facilities in the megawatt range; Sicherheitstechnische Analyse und Auslegungsaspekte von Abschirmungen gegen Teilchenstrahlung am Beispiel von Spallationsanlagen im Megawatt Bereich

    Energy Technology Data Exchange (ETDEWEB)

    Hanslik, R.

    2006-08-15

    This paper discusses the shielding of particle radiation from high current accelerators, spallation neutron sources and so called ADS-facilities (Accelerator Driven Systems). ADS-facilities are expected to gain importance in the future for transmutation of long-lived isotopes from fission reactors as well as for energy production. In this paper physical properties of the radiation as well as safety relevant requirements and corresponding shielding concepts are discussed. New concepts for the layout and design of such shielding are presented. Focal point of this work will be the fundamental difference between conventional fission reactor shielding and the safety relevant issues of shielding from high-energy radiation. Key point of this paper is the safety assessment of shielding issues of high current accelerators, spallation targets and ADS-blanket systems as well as neutron scattering instruments at spallation neutron sources. Safety relevant shielding requirements are presented and discussed. For the layout and design of the shielding for spallation sources computer base calculations methods are used. A discussion and comparison of the most important methods like semi-empirical, deterministic and stochastic codes are presented. Another key point within the presented paper is the discussion of shielding materials and their shielding efficiency concerning different types of radiation. The use of recycling material, as a cost efficient solution, is discussed. Based on the conducted analysis, flowcharts for a systematic layout and design of adequate shielding for targets and accelerators have been developed and are discussed in this paper. By use of these flowcharts layout and engineering design of future ADS-facilities can be performed. (orig.)

  3. An attenuation Layer for Electromagnetic Shielding in X- Band Frequency

    Directory of Open Access Journals (Sweden)

    vida Zaroushani

    2015-06-01

    Full Text Available Uncontrolled exposure to X-band frequency leads to health damage. One of the principles of radiation protection is shielding. But, conventional shielding materials have disadvantages. Therefore, studies of novel materials, as an alternative to conventional shielding materials, are required to obtain new electromagnetic shielding material. Therefore, this study investigated the electromagnetic shielding of two component epoxy thermosetting resin for the X - band frequency with workplace approach. Two components of epoxy resin mixed according to manufacturing instruction with the weight ratio that was 100:10 .Epoxy plates fabricated in three different thicknesses (2, 4 and 6mm and shielding effectiveness measured by Vector Network Analyzer. Then, shielding effectiveness measured by the scattering parameters.The results showed that 6mm thickness of epoxy had the highest and 2mm had the lowest average of shielding effectiveness in X-band frequency that is 4.48 and 1.9 dB, respectively. Also, shielding effectiveness increased by increasing the thickness. But this increasing is useful up to 4mm. Percentage shielding effectiveness of attenuation for 6, 4 and 2mm thicknesses is 64.35%, 63.31% and 35.40%. Also, attenuation values for 4mm and 6mm thicknesses at 8.53 GHz and 8.52 GHz frequency are 77.15% and 82.95%, respectively, and can be used as favourite shields for the above frequency. 4mm-Epoxy is a suitable candidate for shielding application in X-band frequency range but, in the lower section, 6mm thickness is recommended. Finely, the shielding matrix can be used for selecting the proper thickness for electromagnetic shielding in X- Band frequency.

  4. A comparative study on electromagnetic interference shielding behaviors of chemically reduced and thermally reduced graphene aerogels.

    Science.gov (United States)

    Bi, Shuguang; Zhang, Liying; Mu, Chenzhong; Lee, Heng Yeong; Cheah, Jun Wei; Chua, Eng Kee; See, Kye Yak; Liu, Ming; Hu, Xiao

    2017-04-15

    Electromagnetic interference (EMI) shielding performance of chemically and thermally reduced graphene aerogels (GAs) was systematically studied. The EMI shielding mechanisms were extensively analyzed in terms of the distinct surface characteristics resulted from the different reduction methods for the first time. EMI shielding effectiveness (SE) of chemically and thermally reduced GAs reached 27.6 (GAC) and 40.2dB (GAT) at the thickness of 2.5mm, respectively. It was found that the introduction of nitrogen atoms through chemical reduction induced localized charges on the carbon backbone leading to strong polarization effects of GAC. The relatively incomplete reduction caused a large number of side polar groups which prevented the graphene sheets from π-π stacking. In contrast, the higher extent of reduction of graphene sheets in GAT left a smaller amount of side polar groups and formed more sp 2 graphitic lattice, both factors favored π-π stacking between the adjacent graphene sheets, resulting in higher electrical conductivity and enhanced EMI SE. The EMI shielding performance of the GAs prepared outperformed the recent reported porous carbon materials with respect to the absolute SE value at the similar thickness and/or density. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Impact of image noise levels, scout scan dose and lens shield on image quality and radiation exposure in z-axis dose-modulated neck MSCT on 16- and 64-slice Toshiba Aquilion scanners.

    Science.gov (United States)

    Bauknecht, Hans-Christian; Jach, Cornelia; Bohner, Georg; Meyer, Henning; Scheurig, Christian; Siebert, Eberhard; Klingebiel, Randolf

    2010-02-01

    Assessing the impact of image noise (IN) levels, scout scan dose and lens shield use on image quality and radiation exposure in neck multislice CT (MSCT) when using z-axis dose modulation (DM). Neck MSCT phantom studies with/without z-axis DM were performed by using different IN levels (S.D. 7.5-30HU) and scout scan tube currents (7.5-50mA) on Toshiba Aquilion scanners (16-/64-slice). Image quality indices were evaluated by two radiologists and radiation exposure parameters calculated. Cadaveric phantom measurements elucidated lens shield interactions with DM efficacy. The lowest dose scan protocol with diagnostic image quality was introduced into the clinical imaging routine and retrospectively evaluated in 20 age-matched patients undergoing neck MSCT with/without DM. The highest image noise level in DM neck studies with comparable image quality to standard neck CT amounted to 20HU, resulting in a mean tube current of 50mAs (CTDI(w) 6.3mGy). DM reduced effective dose by 35% and organ dose figures (lens, thyroid) by 33%. Scout scan dose lowering to 20mA resulted in an effective dose (ED) decrease of 0.06mSv (5%). Avoiding lens shield placement during scout scan effected an organ dose decrease of 20%. Overall contour sharpness and image contrast did not differ significantly (DM/without DM) whereas image noise was rated higher in DM neck CT studies (pToshiba Aquilion scanners, is effective and mandatory in neck MSCT. DM efficacy can be enhanced by optimising scout scan doses and lens shield use. Copyright (c) 2008 Elsevier Ireland Ltd. All rights reserved.

  6. Evaluation of the frequency and accuracy of gonad shield placement in patients undergoing pelvic radiography

    Energy Technology Data Exchange (ETDEWEB)

    Karami, V.; Zabihzadeh, Mansour; Sarikhani, S. [Ahvaz Jundishapur University of Medical Sciences, Ahvaz (Iran, Islamic Republic of)

    2016-11-01

    Gonad shielding has been advocated to reduce radiation exposure in patients undergoing pelvic radiography. The aim of this study is to evaluate the frequency and accuracy of gonad shield placement in patients undergoing pelvic radiography. A retrospective study was performed on 1230 anteroposterior (AP) pelvic radiographs of 939 children under 16 years old. All the radiographs were reviewed to determine the frequency of gonad shielding and to evaluate whether gonad shields were correctly positioned when they are used. The gonad shield was present in 82 radiographs (30 girls and 52 boys) and was completely disregarded in 1148 radiographs. From 82 images which shield was present, the gonad shields adequately positioned in 28 radiographs (3 girls and 25 boys) and in the remaining 54 radiographs, the shield did not adequately protected the gonads due to incorrect placement of the shield. The inaccuracy placement and absence of gonad shields were more common in girls than boys (P-value < 0.05). More care should be taken to correctly positioning of the gonad shields in boys and its usage should be encouraged. However, the practice of ovarian shielding is not an effective way to reduce radiation exposure in girls undergoing pelvis radiography. (author)

  7. Mathematical Modeling of Optical Radiation Emission as a Function of Welding Power during Gas Shielded Metal Arc Welding.

    Science.gov (United States)

    Bauer, Stefan; Janßen, Marco; Schmitz, Martin; Ott, Günter

    2017-11-01

    Arc welding is accompanied by intense optical radiation emission that can be detrimental not only for the welder himself but also for people working nearby or for passersby. Technological progress advances continuously in the field of joining, so an up-to-date radiation database is necessary. Additionally, many literature irradiance data have been measured for a few welding currents or for parts of the optical spectral region only. Within this paper, a comprehensive study of contemporary metal active gas, metal inert gas, and cold metal transfer welding is presented covering optical radiation emission from 200 up to 2,700 nm by means of (spectro-) radiometric measurements. The investigated welding currents range from 70 to 350 A, reflecting values usually applied in industry. Based upon these new irradiance data, three mathematical models were derived in order to describe optical radiation emission as a function of welding power. The linear, exponential, and sigmoidal emission models depend on the process variant (standard or pulsed) as well as on the welding material (mild and stainless steel, aluminum). In conjunction with the corresponding exposure limit values for incoherent optical radiation maximum permissible exposure durations were calculated as a function of welding power. Typical times are shorter than 1 s for the ultraviolet spectral region and range from 1 to 10 s for visible radiation. For the infrared regime, exposure durations are of the order of minutes to hours. Finally, a validation of the metal active gas emission models was carried out with manual arc welding.

  8. Comparison of radiation dose to operator between transradial and transfemoral coronary angiography with optimised radiation protection: a phantom study.

    Science.gov (United States)

    Liu, Huiliang; Jin, Zhigeng; Jing, Limin

    2014-03-01

    A growing concern in applying radial access in cardiac catheterisation is the increased operator radiation exposure. This study used an anthropomorphic phantom to simulate transradial and transfemoral coronary angiography with optimised radiation protection conditions. Operator radiation exposure was measured with thermoluminescent dosemeters at predefined locations. Compared with the femoral route, the radial route was associated with a dose decrease of 15 % at the operator's chest level with optimised radiation shielding. However, radiation exposure to the operator's hand remained significantly higher when applying radial access even with collective protective equipment used (by a factor of 2). Furthermore, the efficiency of operator radiation protection was found to be dependent on the tube incidence. Awareness should be raised about the significant increase of radiation exposure to operators' hands in transradial coronary angiography. Protection to reduce the dose level to the hands is necessary and should be further improved.

  9. Ab initio study, investigation of NMR shielding tensors, NBO and ...

    African Journals Online (AJOL)

    The bond lengths, bond angles, dipole moment, electron affinity, ionization potential, electronegativy, absolute hardness, highest occupied molecular orbital (HOMO) and the energy of the lowest unoccupied molecular orbital (LUMO) of the studied compounds were calculated in gas phase and water. NMR analysis of ...

  10. Characteristic Analysis of Concrete for Radiation Shielding Evaluation of Gamma Irradiation Facilities

    Science.gov (United States)

    Han, Ki-tek; Kang, Sang Mook; Min, Jeho; Jang, Han Ki

    2017-09-01

    Physical and chemical properties of concrete sample was obtained using various methods such as density analysis, elemental analysis and WD-XRF analysis to get accurate characteristics of concrete collected in our construction site in Korea. Using these results, in this study, we perform the simulation to compare the dose evaluation results between NBS concrete of ANSI/ANS 6.4.3 and characteristics of concrete samples using MCNPX. As a result, simulation results of collected concrete samples in our facility were underestimated up to 54.01%. Through these results, we verify the necessity of accurate properties of materials.

  11. Desert Research and Technology Studies Exposure of Lotus Coated Electrodynamic Shield Samples

    Science.gov (United States)

    Rodriquez, Marcello; Peters, Wanda C.; Straka, Sharon A.; Jones, Craig B.

    2011-01-01

    The Lotus dust mitigation coating and the electrodynamic shield (EDS) are two new technologies currently being developed by NASA as countermeasures for addressing dust accumulation for long-duration human space exploration. These combined technologies were chosen by the Habitation Demonstration Unit (HDU) program for desert dust exposure at the Desert Research and Technologies Studies (D-RaTS) test site in Arizona. Characterization of these samples was performed prior to, during and post D-RaTS exposure.

  12. Space nuclear reactor shields for manned and unmanned applications

    Science.gov (United States)

    Mckissock, Barbara I.; Bloomfield, Harvey S.

    1990-01-01

    Missions which use nuclear reactor power systems require radiation shielding of payload and/or crew areas to predetermined dose rates. Since shielding can become a significant fraction of the total mass of the system, it is of interest to show the effect of various parameters on shield thickness and mass for manned and unmanned applications. Algorithms were developed to give the thicknesses needed if reactor thermal power, separation distances, and dose rates are given as input. The thickness algorithms were combined with models for four different shield geometries to allow tradeoff studies of shield volume and mass for a variety of manned and unmanned missions. Shield design tradeoffs presented in this study include the effects of: higher allowable dose rates; radiation hardened electronics; shorter crew exposure times; shield geometry; distance of the payload and/or crew from the reactor; and changes in the size of the shielded area. Specific NASA missions that were considered in this study include unmanned outer planetary exploration, manned advanced/evolutionary Space Station, and advanced manned lunar base.

  13. New gadolinium based glasses for gamma-rays shielding materials

    Energy Technology Data Exchange (ETDEWEB)

    Kaewjang, S.; Maghanemi, U.; Kothan, S. [Department of Radiologic Technology, Faculty of Associated Medical Sciences, Chang Mai University, Chang Mai 50200 (Thailand); Kim, H.J. [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Limkitjaroenporn, P. [Center of Excellence in Glass Technology and Materials Science (CEGM), Nakhon Pathom Rajabhat University, Nakhon Pathom 73000 (Thailand); Kaewkhao, J., E-mail: mink110@hotmail.com [Center of Excellence in Glass Technology and Materials Science (CEGM), Nakhon Pathom Rajabhat University, Nakhon Pathom 73000 (Thailand)

    2014-12-15

    Highlights: • Gd{sub 2}O{sub 3} based glasses have been fabricated and investigated radiation shielding properties between 223 and 662 keV. • Density of the glass increases with increasing of Gd{sub 2}O{sub 3.} • All the glasses of Gd{sub 2}O{sub 3} compositions studied had been shown lower HVL than X-rays shielding window. • Prepared glasses to be utilized as radiation shielding material with Pb-free advantage. • This work is the first to reports on radiation shielding properties of Gd{sub 2}O{sub 3} based glass matrices. - Abstract: In this work, Gd{sub 2}O{sub 3} based glasses in compositions (80−x)B{sub 2}O{sub 3}-10SiO{sub 2}-10CaO-xGd{sub 2}O{sub 3} (where x = 15, 20, 25, 30 and 35 mol%) have been fabricated and investigated for their radiation shielding, physical and optical properties. The density of the glass was found to increase with the increasing of Gd{sub 2}O{sub 3} concentration. The experimental values of mass attenuation coefficients (μ{sub m}), effective atomic number (Z{sub eff}) and effective electron densities (N{sub e}) of the glasses were found to increase with the increasing of Gd{sub 2}O{sub 3} concentration and also with the decreasing of photon energy from 223 to 662 keV. The glasses of all Gd{sub 2}O{sub 3} compositions studied have been shown with lower HVL values in comparison to an X-rays shielding window, ordinary concrete and commercial window; indicating their potential as radiation shielding materials with Pb-free advantage. Optical spectra of the glasses in the present study had been shown with light transparency; an advantage when used as radiation shielding materials.

  14. Shielding properties of the ordinary concrete loaded with micro- and nano-particles against neutron and gamma radiations.

    Science.gov (United States)

    Mesbahi, Asghar; Ghiasi, Hosein

    2018-02-03

    The shielding properties of ordinary concrete doped with some micro and nano scaled materials were studied in the current study. Narrow beam geometry was simulated using MCNPX Monte Carlo code and the mass attenuation coefficient of ordinary concrete doped with PbO 2 , Fe 2 O 3 , WO 3 and H 4 B (Boronium) in both nano and micro scales was calculated for photon and neutron beams. Mono-energetic beams of neutrons (100-3000 keV) and photons (142-1250 keV) were used for calculations. The concrete doped with nano-sized particles showed higher neutron removal cross section (7%) and photon attenuation coefficient (8%) relative to micro-particles. Application of nano-sized material in the composition of new concretes for dual protection against neutrons and photons are recommended. For further studies, the calculation of attenuation coefficients of these nano-concretes against higher energies of neutrons and photons and different particles are suggested. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Radiation Hydrodynamic Parameter Study of Inertial Fusion Energy Reactor Chambers

    Science.gov (United States)

    Sacks, Ryan; Moses, Gregory

    2014-10-01

    Inertial fusion energy reactors present great promise for the future as they are capable of providing baseline power with no carbon footprint. Simulation work regarding the chamber response and first wall insult is performed with the 1-D radiation hydrodynamics code BUCKY. Simulation with differing chamber parameters are implemented to study the effect of gas fill, gas mixtures and chamber radii. Xenon and argon gases are of particular interest as shielding for the first wall due to their high opacity values and ready availability. Mixing of the two gases is an attempt to engineer a gas cocktail to provide the maximum amount of shielding with the least amount of cost. A parameter study of different chamber radii shows a consistent relationship with that of first wall temperature (~1/r2) and overpressure (~1/r3). This work is performed under collaboration with Lawrence Livermore National Laboratory.

  16. Conduction mechanism in Polyaniline-flyash composite material for shielding against electromagnetic radiation in X-band & Ku band

    Directory of Open Access Journals (Sweden)

    Avanish Pratap Singh

    2011-06-01

    Full Text Available β–Naphthalene sulphonic acid (β–NSA doped polyaniline (PANI–flyash (FA composites have been prepared by chemical oxidative polymerization route whose conductivity lies in the range 2.37–21.49 S/cm. The temperature dependence of electrical conductivity has also been recorded which shows that composites follow Mott's 3D–VRH model. SEM images demonstrate that β–NSA leads to the formation of the tubular structure with incorporated flyash phase. TGA studies show the improvement in thermal stability of composites with increase in loading level of flyash. Complex parameters i.e. permittivity (ɛ* = ɛ′- iɛ″ and permeability (μ*=μ′- iμ″ of PANI-FA composites have been calculated from experimental scattering parameters (S11 & S21 using theoretical calculations given in Nicholson–Ross and Weir algorithms. The microwave absorption properties of the composites have been studied in X-band (8.2 – 12.4 GHz & Ku–Band (12.4 – 18 GHz frequency range. The maximum shielding effectiveness observed was 32dB, which strongly depends on dielectric loss and volume fraction of flyash in PANI matrix.

  17. A comprehensive study of the energy absorption and exposure buildup factors of different bricks for gamma-rays shielding

    Directory of Open Access Journals (Sweden)

    M.I. Sayyed

    Full Text Available The present investigation has been performed on different bricks for the purpose of gamma-ray shielding. The values of the mass attenuation coefficient (µ/ρ, energy absorption buildup factor (EABF and exposure buildup factor (EBF were determined and utilized to assess the shielding effectiveness of the bricks under investigation. The mass attenuation coefficients of the selected bricks were calculated theoretically using WinXcom program and compared with MCNPX code. Good agreement between WinXcom and MCNPX results was observed. Furthermore, the EABF and EBF have been discussed as functions of the incident photon energy and penetration depth. It has been found that the EABF and EBF values are very large in the intermediate energy region. The steel slag showed good shielding properties, consequently, this brick is eco-friendly and feasible compared with other types of bricks used for construction. The results in this work should be useful in the construction of effectual shielding against hazardous gamma-rays. Keywords: Brick, Mass attenuation coefficient, Buildup factor, G-P fitting, Radiation shielding

  18. TFCX shielding optimization

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S.; Gohar, Y.

    1985-01-01

    Design analyses and tradeoff studies for the bulk shield of the Tokamak Fusion Core Experiment (TFCX) were performed. Several shielding options were considered to lower the capital cost of the shielding system. Optimization analyses were carried out to reduce the nuclear responses in the TF coils and the dose equivalent in the reactor hall one day after shutdown. Two TFCX designs with different toroidal field (TF) coil configurations were considered during this work. The materials for the shield were selected based upon tradeoff studies and the results from the previous design studies. The main shielding materials are water, concrete, and steel balls (Fe1422 or Nitronic 33). Small amounts of boron carbide and lead are employed to reduce activation, nuclear heating in the TF coils, and dose equivalent after shutdown.

  19. Review of ORNL-TSF shielding experiments for the gas-cooled Fast Breeder Reactor Program

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, L.S.; Ingersoll, D.T.; Muckenthaler, F.J.; Slater, C.O.

    1982-01-01

    During the period between 1975 and 1980 a series of experiments was performed at the ORNL Tower Shielding Facility in support of the shield design for a 300-MW(e) Gas Cooled Fast Breeder Demonstration Plant. This report reviews the experiments and calculations, which included studies of: (1) neutron streaming in the helium coolant passageways in the GCFR core; (2) the effectiveness of the shield designed to protect the reactor grid plate from radiation damage; (3) the adequacy of the radial shield in protecting the PCRV (prestressed concrete reactor vessel) from radiation damage; (4) neutron streaming between abutting sections of the radial shield; and (5) the effectiveness of the exit shield in reducing the neutron fluxes in the upper plenum region of the reactor.

  20. Thyroid shields and neck exposures in cephalometric radiography

    Directory of Open Access Journals (Sweden)

    Cunha-Cruz Joana

    2006-06-01

    Full Text Available Abstract Background The thyroid is among the more radiosensitive organs in the body. The goal of this study was twofold: (1 to evaluate age-related changes in what is exposed to ionizing radiation in the neck area, and (2 to assess thyroid shield presence in cephalometric radiographs Methods Cephalometric radiographs at one academic setting were sampled and neck exposure was related to calendar year and patient's gender and age. Results In the absence of shields, children have more vertebrae exposed than adults (p Conclusion In the absence of a thyroid shield, children have more neck structure exposed to radiation than adults. In agreement with other reports, thyroid shield utilization in this study was low, particularly in children.

  1. Reliability of transcutaneous bilirubinometry from shielded skin in neonates receiving phototherapy: a prospective cohort study.

    Science.gov (United States)

    Murli, L; Thukral, A; Sankar, M J; Vishnubhatla, S; Deorari, A K; Paul, V K; Sakariah, A; Dolma; Agarwal, R

    2017-02-01

    To determine the agreement between transcutaneous bilirubin (TcB) measured from shielded skin and serum total bilirubin (STB) in infants (34 to 41 weeks of gestation) with hyperbilirubinemia receiving phototherapy (PT). In this prospective cohort study, we shielded a small area of skin on sternum using a commercial photo-opaque patch (BilEclipseTM, Philips Respironics, Murrysville, PA, USA). The TcB from the shielded skin (TcBs) and STB were measured at four time points-before initiation, 12 and 24 h during and once after (12 h) cessation of PT. TcB was measured using multiwavelength transcutaneous bilirubinometer (BiliChek, Philips Children's Medical Ventures, Monroeville, PA, USA). The STB was measured in triplicate by spectrophotometry (Apel BR 5100, APEL, Japan). Bland and Altman plots were drawn to determine agreement between the TcBs and STB. The gestation and birth weight of enrolled neonates were 37.0 (1.0) weeks and 2750 (458) g, respectively. The age at initiation and duration of PT were 75 (27 to 312) and 25.3 (4.4) h, respectively. Bland and Altman plot showed poor agreement between TcBs and STB at all time points. The gradient (median, range) between TcBs and STB at 0, 12, 24 h and 12 h after cessation of PT were -0.2 (-4.9 to 3.5), 1.4 (-4.7 to 4.0), 1.5 (-3.8 to 9.4) and 2 (-2.9 to 5.8) mg dl-1. The proportions of TcBs values outside ±1.5 mg dl-1 of STB ranged from 47 to 64% at four time points. TcBs does not appear to be reliable for estimating serum bilirubin in late preterm and term neonates receiving PT.

  2. Investigation of Main Radiation Source above Shield Plug of Unit 3 at Fukushima Daiichi Nuclear Power Station

    Science.gov (United States)

    Hiratama, Hideo; Kondo, Kenjiro; Suzuki, Seishiro; Tanimura, Yoshihiko; Iwanaga, Kohei; Nagata, Hiroshi

    2017-09-01

    Pulse height distributions were measured using a CdZnTe detector inside a lead collimator to investigate main source producing high dose rates above the shield plugs of Unit 3 at Fukushima Daiichi Nuclear Power Station. It was confirmed that low energy photons are dominant. Concentrations of Cs-137 under 60 cm concrete of the shield plug were estimated to be between 8.1E+9 and 5.7E+10 Bq/cm2 from the measured peak count rate of 0.662 MeV photons. If Cs-137 was distributed on the surfaces of the gaps with radius 6m and with the averaged concentration of 5 points, 2.6E+10 Bq/cm2, total amount of Cs-137 is estimated to be 30 PBq.

  3. Investigation of Main Radiation Source above Shield Plug of Unit 3 at Fukushima Daiichi Nuclear Power Station

    Directory of Open Access Journals (Sweden)

    Hiratama Hideo

    2017-01-01

    Full Text Available Pulse height distributions were measured using a CdZnTe detector inside a lead collimator to investigate main source producing high dose rates above the shield plugs of Unit 3 at Fukushima Daiichi Nuclear Power Station. It was confirmed that low energy photons are dominant. Concentrations of Cs-137 under 60 cm concrete of the shield plug were estimated to be between 8.1E+9 and 5.7E+10 Bq/cm2 from the measured peak count rate of 0.662 MeV photons. If Cs-137 was distributed on the surfaces of the gaps with radius 6m and with the averaged concentration of 5 points, 2.6E+10 Bq/cm2, total amount of Cs-137 is estimated to be 30 PBq.

  4. Mathematical modeling of the radiation dose received from photons passing over and through shielding walls in a PET/CT suite

    DEFF Research Database (Denmark)

    Fog, Lotte S; Cormack, John

    2010-01-01

    Given that the financial cost of shielding PET/CT suites can be substantial, it has become increasingly important to be able to accurately assess the thickness of shielding required for barriers and whether it is necessary to extend such shielding all the way to the ceiling. The overall shielding...

  5. Radioprotection to the Gonads in Pediatric Pelvic Radiography: Effectiveness of Developed Bismuth Shield

    Directory of Open Access Journals (Sweden)

    Vahid Karami

    2017-06-01

    Full Text Available Background: The use and effectiveness of traditional lead gonad shields in pediatric pelvic radiography has been challenged by several literatures over the past two decades. The aim of this study was to develop a new radioprotective gonad shields to be use in pediatric pelvic radiography. Materials and Methods: The commercially available 0.06 mm lead equivalent bismuth garment has cropped squarely and used as ovarian shield to cover the entire region of pelvis. In order to prevent deterioration of image quality due to beam hardening artifacts, a 1-cm foam as spacer was located between the shield and patients pelvis. Moreover, we added a lead piece at the cranial position of the bismuth garment to absorb the scatter radiations to the radiosensitive organs. In girls, 49 radiographs with shield and 46 radiographs without shield was taken. The radiation dose was measured using thermoluminescent dosimeters (TLDs. Image quality assessments were performed using the European guidelines. For boys, the lead testicular shields was developed using 2 cm bismuth garment, added to the sides. The prevalence and efficacy of testicular shields was assessed in clinical practice fromFebruary 2016 to June 2016. Results: Without increasing the dose to the breast, thyroid and the lens of the eyes, the use of bismuth shield has reduced the entrance skin dose(ESD of the pelvis and radiation dose to the ovaries by 62.2% and 61.7%, respectively (P

  6. Evaluation and redesign of radiation shielding in a radionuclide production facility at a particle accelerator / Onalenna Kegopotsemang

    OpenAIRE

    Kegopotsemang, Onalenna

    2004-01-01

    iThemba LABS is a particle accelerator facility housing a radionuclide production facility that uses a 66 MeV proton beam to produce radionuclides for medical and industrial use. Ionising radiation is produced by a variety of sources at Themba LABS. Ionising is a health hazard. High doses can cause acute radiation syndrome, i.e. "radiation sickness". Lower doses cannot cause acute symptom, but carry a risk of radiation-related cancer. Ionising radiation is also detrimental to materials, and c...

  7. Studies on the efficiency of the neutron shielding for the SIMPLE dark matter search

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, A.C., E-mail: anafer@itn.p [Instituto Tecnologico e Nuclear, Unidade de Reactores e Seguranca Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto, 2, 1649-003 Lisboa (Portugal); Felizardo, M. [Departamento de Fisica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Instituto Tecnologico e Nuclear, Unidade de Reactores e Seguranca Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Kling, A.; Marques, J.G. [Instituto Tecnologico e Nuclear, Unidade de Reactores e Seguranca Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto, 2, 1649-003 Lisboa (Portugal); Morlat, T. [Centro de Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto, 2, 1649-003 Lisboa (Portugal)

    2010-11-21

    The SIMPLE project for direct dark matter search is located in a deep underground laboratory, where non-WIMP signals are expected due to neutrons and alpha particles naturally occurring in the facility. This work presents a first study on the efficiency of the neutron shielding for SIMPLE and possible routes for its optimization. The evaluation of the neutron component considers spontaneous fission and ({alpha},n) neutrons originating from the {sup 238}U and {sup 232}Th present in the experiment materials. Using recently published data on ({alpha},n) yields and spectra, a Monte Carlo model using the MCNP code is employed to simulate the transport of both spontaneous fission and ({alpha},n) neutrons. The application of MCNP offers an alternative method to the SOURCES code used systematically by others for the evaluation of the ({alpha},n) component. Results supporting the optimization of the neutron shield for SIMPLE are described and the feasibility of reducing the event rate to less than 1 evt/kgd is demonstrated.

  8. Self-generated clouds of micron-sized particles as a promising way of a Solar Probe shielding from intense thermal radiation of the Sun

    Science.gov (United States)

    Dombrovsky, Leonid A.; Reviznikov, Dmitry L.; Kryukov, Alexei P.; Levashov, Vladimir Yu

    2017-10-01

    An effect of shielding of an intense solar radiation towards a solar probe with the use of micron-sized SiC particles generated during ablation of a composite thermal protection material is estimated on a basis of numerical solution to a combined radiative and heat transfer problem. The radiative properties of particles are calculated using the Mie theory, and the spectral two-flux model is employed in radiative transfer calculations for non-uniform particle clouds. A computational model for generation and evolution of the cloud is based on a conjugated heat transfer problem taking into account heating and thermal destruction of the matrix of thermal protection material and sublimation of SiC particles in the generated cloud. The effect of light pressure, which is especially important for small particles, is also taken into account. The computational data for mass loss due to the particle cloud sublimation showed the low value about 1 kg/m2 per hour at the distance between the vehicle and the Sun surface of about four radii of the Sun. This indicates that embedding of silicon carbide or other particles into a thermal protection layer and the resulting generation of a particle cloud can be considered as a promising way to improve the possibilities of space missions due to a significant decrease in the vehicle working distance from the solar photosphere.

  9. Composite Aerogel Multifoil Protective Shielding

    Science.gov (United States)

    Jones, Steven M.

    2013-01-01

    New technologies are needed to survive the temperatures, radiation, and hypervelocity particles that exploration spacecraft encounter. Multilayer insulations (MLIs) have been used on many spacecraft as thermal insulation. Other materials and composites have been used as micrometeorite shielding or radiation shielding. However, no material composite has been developed and employed as a combined thermal insulation, micrometeorite, and radiation shielding. By replacing the scrims that have been used to separate the foil layers in MLIs with various aerogels, and by using a variety of different metal foils, the overall protective performance of MLIs can be greatly expanded to act as thermal insulation, radiation shielding, and hypervelocity particle shielding. Aerogels are highly porous, low-density solids that are produced by the gelation of metal alkoxides and supercritical drying. Aerogels have been flown in NASA missions as a hypervelocity particle capture medium (Stardust) and as thermal insulation (2003 MER). Composite aerogel multifoil protective shielding would be used to provide thermal insulation, while also shielding spacecraft or components from radiation and hypervelocity particle impacts. Multiple layers of foil separated by aerogel would act as a thermal barrier by preventing the transport of heat energy through the composite. The silica aerogel would act as a convective and conductive thermal barrier, while the titania powder and metal foils would absorb and reflect the radiative heat. It would also capture small hypervelocity particles, such as micrometeorites, since it would be a stuffed, multi-shock Whipple shield. The metal foil layers would slow and break up the impacting particles, while the aerogel layers would convert the kinetic energy of the particles to thermal and mechanical energy and stop the particles.

  10. Development of highly effective neutron shielding material made of phenol-novolac type epoxy resin

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Soo Haeng; Jeong, Myeong Soo; Hong, Sun Seok; Lee, Won Kyoung; Kim, Ik Soo; Shin, Young Joon; Do, Jae Bum; Ro, Seung Gy; Oh, Seok Jin

    1998-06-01

    Because the exposure to radiation in the nuclear facilities can be fatal to human, it is important to reduce the radiation dose level to a tolerable level. The purpose of this study is to develop highly effective neutron shielding materials for the shipping and storage cask of radioactive materials or in the nuclear/radiation facilities. On this study, we developed epoxy resin based neutron shielding materials and their various material properties, including neutron shielding ability, fire resistance, combustion characteristics, radiation resistance, thermal and mechanical properties were evaluated experimentally. Especially we developed phenol-novolac type epoxy resin based neutron shielding materials and their characteristics were also evaluated. (author). 22 refs., 11 tabs., 21 figs

  11. Infrared shield facilitates optical pyrometer measurements

    Science.gov (United States)

    Eichenbrenner, F. F.; Illg, W.

    1965-01-01

    Water-cooled shield facilitates optical pyrometer high temperature measurements of small sheet metal specimens subjected to tensile stress in fatigue tests. The shield excludes direct or reflected radiation from one face of the specimen and permits viewing of the infrared radiation only.

  12. An evaluation of buccal shield treatment. A clinical and cephalometric study.

    Science.gov (United States)

    Moin, Kambiz; Bishara, Samir E

    2007-01-01

    To evaluate the short-term effects of the buccal shield modification of the lip-bumper design and on various mandibular dental arch parameters and to determine whether the changes in arch widths are due to the tipping or bodily movements of the teeth involved. This study included 45 consecutively treated patients (29 girls and 16 boys) from a private orthodontic practice. Student's and paired t-tests were used to test the null hypothesis of no change over time for the various measurements. Linear regression analyses were used to determine whether treatment time was a significant predictor of arch width expansion. Significance for all statistical tests was predetermined at P < or = .05. Student's t-test results indicated the presence of a significant (P < .0001) increase in all the arch parameters measured. The greatest mean expansion was observed at the first (5.0 +/- 2.2 mm) and second (3.4 +/- 2.2 mm) premolar width measurements. The changes in arch width parameters were significantly (P < .0001) greater than the normal age-related changes in the corresponding parameters. There was no significant difference between arch width expansion of the occlusal vs gingival levels, indicating a bodily and not tipping movement. Only 30% of the lower incisors demonstrated an increase in their proclination beyond normal values. When using the buccal shield appliance, the mandibular arch width parameters can be expanded in the mixed dentition with bodily movement of teeth. The expanded arch width dimensions are greater than what would be expected as a result of normal growth.

  13. Prototyping studies for the Blanket Shield Module of the ITER ECH Upper Port Plug

    Energy Technology Data Exchange (ETDEWEB)

    Spaeh, P. [Forschungszentrum Karlsruhe, Association FZK-Euratom, Institute for Materials Research I, P.O. Box 3640, D-76021 Karlsruhe (Germany)], E-mail: peter.spaeh@imf.fzk.de; Heidinger, R.; Kleefeldt, K.; Meier, A.; Scherer, T.; Strauss, D. [Forschungszentrum Karlsruhe, Association FZK-Euratom, Institute for Materials Research I, P.O. Box 3640, D-76021 Karlsruhe (Germany)

    2009-06-15

    A team of European associations is planning to procure ECH launcher turnkey systems for MHD control in the ITER plasma. ECH launchers will be installed to four ports on the upper level of the ITER vacuum vessel (VV). The structural system of the launchers accommodates the mm-wave components, cooling devices and elements for nuclear shielding. Its main components are the Blanket Shield Module (BSM), including the plasma facing First Wall Panel (FWP) and the port plug mainframe. A removable flange connection between the BSM and the main frame provides access to the internals. Appropriate remote handling capability is also taken as a design requirement. The BSM with the flange connection will be exposed to substantial nuclear heat loads. The manufacturing of machined components requires complex shaping with small tolerances and good quality of the surfaces due to operation under vacuum conditions. For the BSM and the front segment of the main frame a rigid double wall structure with meandering rectangular cooling channels was designed and analysed to meet these requirements. To investigate industrial manufacturing routes, a typical single-piece sample was machined and the manufacturing process was evaluated. Further two prototypes of a characteristic section of the BSM were manufactured, using two different fabrication techniques. These are (a) Hot Isostatic Pressing (HIP), which combines the sintering of metal powder inside of welded capsules and diffusion welding of solid parts and (b) brazing of bent and machined individual parts. The prototypes are under study at the Launcher Handling Test facility (LHT) at FZK, which offers a water circuit to provide coolant with adjustable parameters, simulating different ITER operating conditions. Extensive test series were performed to validate underlying analysis related to homogenous temperature distribution, tolerable pressure drop within the cooling paths and removal of applied heat loads.

  14. Study on the adjustment capability of the excitation system located inside superconducting machine electromagnetic shield

    Science.gov (United States)

    Xia, D.; Xia, Z.

    2017-12-01

    The ability for the excitation system to adjust quickly plays a very important role in maintaining the normal operation of superconducting machines and power systems. However, the eddy currents in the electromagnetic shield of superconducting machines hinder the exciting magnetic field change and weaken the adjustment capability of the excitation system. To analyze this problem, a finite element calculation model for the transient electromagnetic field with moving parts is established. The effects of three different electromagnetic shields on the exciting magnetic field are analyzed using finite element method. The results show that the electromagnetic shield hinders the field changes significantly, the better its conductivity, the greater the effect on the superconducting machine excitation.

  15. Neutron guide shielding for the BIFROST spectrometer at ESS

    DEFF Research Database (Denmark)

    Mantulnikovs, K.; Bertelsen, M.; Cooper-Jensen, C.P.

    2016-01-01

    We report on the study of fast-neutron background for the BIFROST spectrometer at ESS. We investigate the effect of background radiation induced by the interaction of fast neutrons from the source with the material of the neutron guide and devise a reasonable fast, thermal/cold neutron shielding...... solution for the current guide geometry using McStas and MCNPX. We investigate the effectiveness of the steel shielding around the guide by running simulations with three different steel thicknesses. The same approach is used to study the efficiencies of the steel wall a flat cylinder pierced by the guide...... in the middle and the polyethylene layer. The final model presented here has a 3 cm thick steel shielding around the guide, 30 cm of polyethylene around the shielding, two 5 mm thick B4C layers and a steel wall at position Z = 38 m, being 1 m thick and 10 m in radius. The final model finally proves...

  16. 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...

  17. Experimental Study on Electromagnetic Shielding Characteristics of Conductive O-rings at High Frequencies

    Science.gov (United States)

    Yamamoto, Shinnichiro; Hatakeyama, Kennichi; Yamada, Takeshi

    The O-rings have been usually applied to mechanically moving parts for sealing oil and air and preventing dust so far. In order to measure the electromagnetic shielding effectiveness of the conductive O-rings, we proposed a electromagnetic shielding evaluation setup for the O-ring. There are two ways to apply O-rings in narrow gaps, cylinder-fixing and plane-fixing. By the use of this setup, the electromagnetic shielding effectiveness of conductive O-rings can be evaluated from 10kHz to 1GHz for both fixing types. The reflection and transmission characteristics of this setup and measured results of electromagnetic shielding effects are described. Anisotropic conductivity of the ring material and an equivalent circuit of the O-rings are discussed.

  18. Hybrid Wing Body Shielding Studies Using an Ultrasonic Configurable Fan Artificial Noise Source Generating Typical Turbofan Modes

    Science.gov (United States)

    Sutliff, Daniel l.; Brown, Clifford A.; Walker, Bruce E.

    2014-01-01

    An Ultrasonic Configurable Fan Artificial Noise Source (UCFANS) was designed, built, and tested in support of the NASA Langley Research Center's 14- by 22-ft wind tunnel test of the Hybrid Wing Body (HWB) full 3-D 5.8 percent scale model. The UCFANS is a 5.8 percent rapid prototype scale model of a high-bypass turbofan engine that can generate the tonal signature of proposed engines using artificial sources (no flow). The purpose of the test was to provide an estimate of the acoustic shielding benefits possible from mounting the engine on the upper surface of an HWB aircraft using the projected signature of the engine currently proposed for the HWB. The modal structures at the rating points were generated from inlet and exhaust nacelle configurations--a flat plate model was used as the shielding surface and vertical control surfaces with correct plan form shapes were also tested to determine their additional impact on shielding. Radiated acoustic data were acquired from a traversing linear array of 13 microphones, spanning 36 in. Two planes perpendicular, and two planes parallel, to the axis of the nacelle were acquired from the array sweep. In each plane the linear array traversed four sweeps, for a total span of 168 in. acquired. The resolution of the sweep is variable, so that points closer to the model are taken at a higher resolution. Contour plots of Sound Pressure Levels, and integrated Power Levels, from nacelle alone and shielded configurations are presented in this paper; as well as the in-duct mode power levels

  19. Study on Load-displacement Test of Rubber Pads of Coal Mine Roadway Constructed by Shield

    Science.gov (United States)

    Yang, Yue; Chen, Xiaoguo; Yang, Liyun

    2017-12-01

    Shield method construction of coal mine roadway is the future trend of the development of deep coal mining. The main shaft supporting is the segment. There is rubber pads between segment and segment. The performance of compression deformation of rubber pad is essential for the overall stability of lining. Through load test, displacement of the rubber pad under load, the thrust force law of the rubber pad deformation, and provide a theoretical basis for the stability analysis of coal mine tunnel shield construction.

  20. Electromagnetic interference shielding effectiveness of polypropylene/conducting fiber composites

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Pyoung-Chan, E-mail: pclee@katech.re.kr; Kim, Bo-Ram; Jeoung, Sun Kyoung [Korea Automotive Technology lnstitute, Dongnam-Gu, Chonan-Si, Chungnam 330-912 (Korea, Republic of); Kim, Yeung Keun [Win& Win Co., Ltd., Anseong-Si, Gyeonggi-Do, 456-931 (Korea, Republic of)

    2016-03-09

    Electromagnetic released from the automotive electronic parts is harmful to human body. Electromagnetic interference (EMT) shielding refers to the reflection and/or adsorption of electromagnetic radiation by a material, which thereby acts as a shield against the penetration of the radiation through the shield. Polypropylene (PP)/conductive micro fiber composites containing various fiber contents and fiber length were injection-molded. The effect of fiber content and length on electrical properties of the composites was studied by electrical resistivity and EMT shielding measurements. The through-plane electrical conductivity and dielectric permittivity were obtained by measuring dielectric properties. The EMT shielding effectiveness (SE) was investigated by using S-parameter in the range of 100 ~ 1500 MHz. Reflection, absorption and multiple-reflection are the EMT attenuation mechanisms. From the measurement of S-Parameters, the absorption coefficient, reflection coefficient, and the shielding efficiency of the materials were calculated. The EMT SE of PP/conducing fiber composites is 40 dB over a wide frequency range up to 1.5 GHz, which is higher than that of PP/talc composite used automotive parts, viz. 0 dB.

  1. Monte Carlo simulation for radioisotope production yields calculation and radiation shielding for Rh, RbCl, ZnO, and ga target

    Energy Technology Data Exchange (ETDEWEB)

    Ra, Se Jin; Jung, Myung Hwan; Kim, Kye Ryung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-10-15

    The 100 MeV linear accelerator at the proton engineering frontier project (PEFP) will be operated with average current of 300 {mu}A for 100 MeV beam line and 600 {mu}A for 20 MeV beam line. With this high current proton beam, all proton beam irradiated targets may be highly radio-activated, so we will install hot cell for radiation work. In this paper, we simulated production yield of radioisotopes such as {sup 109}Pd, {sup 82}Sr, {sup 67}Cu, and {sup 68}Ge, so we used natural Rh, RbCl, ZnO, and Ga prototype target of 2-mm thickness. Proton beam irradiation condition is 1-{mu}A current and 1-hour irradiation at all target cases. Also we simulated radiation shielding calculation for 10 cm thickness lead plate. The Monte Carlo codes, MCNPX and PHITS, and the analyzing decay and build-up code, DCHAIN-SP were used to these calculations.

  2. The evaluation of contralateral breast's dose and shielding efficiency by breast size about breast implant patient for radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Wook; Woo, Heon; Jeong, Hyeon Hak; Kim, Kyeong Ah; Kim, Chan Yong; Yoo, Suk Hyun [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2014-12-15

    To evaluate the dose on a contralateral breast and the usefulness of shielding according to the distance between the contralateral breast and the side of the beam by breast size when patients who got breast implant receive radiation therapy. We equipped 200 cc, 300 cc, 400 cc, and 500 cc breast model on the human phantom (Rando-phantom), acquired CT images (philips 16channel, Netherlands) and established the radiation treatment plan, 180 cGy per day on the left breast (EclipseTM ver10.0.42, Varian Medical Systems, USA) by size. We set up each points, A, B, C, and D on the right(contralateral) breast model for measurement by size and by the distance from the beam and attached MOSFET at each points. The 6 MV, 10 MV and 15 MV X-ray were irradiated to the left(target) breast model and we measured exposure dose of contralateral breast model using MOSFET. Also, at the same condition, we acquired the dose value after shielding using only Pb 2 mm and bolus 3 mm under the Pb 2 mm together. As the breast model is bigger from 200 cc to 500 cc, The surface of the contralateral breast is closer to the beam. As a result, from 200 cc to 500 cc, on 180 cGy basis, the measurement value of the scattered ray inclined by 3.22-4.17% at A point, 4.06-6.22% at B point, 0.4-0.5% at C point, and was under 0.4% at D point. As the X-ray energy is higher, from 6 MV to 15 MV, on 180 cGy basis, the measurement value of the scattered ray inclined by 4.06-5% at A point, 2.85-4.94% at B point, 0.74-1.65% at C point, and was under 0.4% at D point. As using Pb 2 mm for shield, scattered ray declined by average 9.74% at A and B point, 2.8% at C point, and is under 1% at D point. As using Pb 2 mm and bolus together for shield, scattered ray declined by average 9.76% at A and B point, 2.2% at C point, and is under 1% at D point. Commonly, in case of patients who got breast implant, there is a distance difference by breast size between the contralateral breast and the side of beam. As the distance is

  3. Considerations on scattering and leak radiation for effective determination of secondary shielding in X-rays rooms of megavoltage; Consideracoes sobre radiacoes de espalhamento e vazamento para determinacao eficaz da barreira secundaria em salas de raios-x de megavoltagem

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Diogo da S.; Lava, Deise D.; Affonso, Renato R.W.; Moreira, Maria de L.; Guimaraes, Antonio C.F., E-mail: diogosb@outlook.com, E-mail: deise_dy@hotmail.com, E-mail: raoniwa@yahoo.com.br, E-mail: malu@ien.gov.br, E-mail: tony@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2014-07-01

    This paper addresses the development of a algorithm capable of analyzing the thickness of the secondary shielding due to the production of secondary beams. The production of this beam requires consideration of scattering angle, as well as factors normally used for screening of medical facilities using radiographic techniques. Besides the beam emanated from scattering radiation, is is necessary to evaluate the contribution of leakage radiation, originating from equipment used for the production of the primary beam. A view of the mutual contribution of these radiation to the formation of the secondary beam has shown the need of using shieldings in adjacent walls of the room. The code was validated by comparison with an example case provided by NCRP-151 Report. In this report calculations for determining the secondary barrier for small angles are presented, that deserves greater attention for shielding and statements related to radiotherapy procedures of Modulated intensity. The results are consistent with those provided in the report, which makes the code can be used as a practical tool for the determination of effective shielding beams of megavoltage X-rays.

  4. Single laser based pump-probe technique to study plasma shielding during nanosecond laser ablation of copper thin films

    Science.gov (United States)

    Nammi, Srinagalakshmi; Vasa, Nilesh J.; Gurusamy, Balaganesan; Mathur, Anil C.

    2017-09-01

    A plasma shielding phenomenon and its influence on micromachining is studied experimentally and theoretically for laser wavelengths of 355 nm, 532 nm and 1064 nm. A time resolved pump-probe technique is proposed and demonstrated by splitting a single nanosecond Nd3+:YAG laser into an ablation laser (pump laser) and a probe laser to understand the influence of plasma shielding on laser ablation of copper (Cu) clad on polyimide thin films. The proposed nanosecond pump-probe technique allows simultaneous measurement of the absorption characteristics of plasma produced during Cu film ablation by the pump laser. Experimental measurements of the probe intensity distinctly show that the absorption by the ablated plume increases with increase in the pump intensity, as a result of plasma shielding. Theoretical estimation of the intensity of the transmitted pump beam based on the thermo-temporal modeling is in qualitative agreement with the pump-probe based experimental measurements. The theoretical estimate of the depth attained for a single pulse with high pump intensity value on a Cu thin film is limited by the plasma shielding of the incident laser beam, similar to that observed experimentally. Further, the depth of micro-channels produced shows a similar trend for all three wavelengths, however, the channel depth achieved is lesser at the wavelength of 1064 nm.

  5. Determination of the exposure speed of radiation emitted by the linear accelerator, using the code MCNP5 to evaluate the radiotherapy room shields of ABC Hospital; Determinacion de la rapidez de exposicion de la radiacion emitida por el acelerador lineal, utilizando el codigo MCNP5, para evaluar los blindajes de la sala de radioterapia del Hospital ABC

    Energy Technology Data Exchange (ETDEWEB)

    Corral B, J. R.

    2015-07-01

    Humans should avoid exposure to radiation, because the consequences are harmful to health. Although there are different emission sources of radiation, generated by medical devices they are usually of great interest, since people who attend hospitals are exposed in one way or another to ionizing radiation. Therefore, is important to conduct studies on radioactive levels that are generated in hospitals, as a result of the use of medical equipment. To determine levels of exposure speed of a radioactive facility there are different methods, including the radiation detector and computational method. This thesis uses the computational method. With the program MCNP5 was determined the speed of the radiation exposure in the radiotherapy room of Cancer Center of ABC Hospital in Mexico City. In the application of computational method, first the thicknesses of the shields were calculated, using variables as: 1) distance from the shield to the source; 2) desired weekly equivalent dose; 3) weekly total dose equivalent emitted by the equipment; 4) occupation and use factors. Once obtained thicknesses, we proceeded to model the bunker using the mentioned program. The program uses the Monte Carlo code to probabilistic ally determine the phenomena of interaction of radiation with the shield, which will be held during the X-ray emission from the linear accelerator. The results of computational analysis were compared with those obtained experimentally with the detection method, for which was required the use of a Geiger-Muller counter and the linear accelerator was programmed with an energy of 19 MV with 500 units monitor positioning the detector in the corresponding boundary. (Author)

  6. Effects of buccal shields on mandibular dental arch parameters: a clinical and cephalometric study.

    Science.gov (United States)

    Moin, Kambiz; Bishara, Samir E

    2007-01-01

    The lip bumper is a vestibular functional appliance designed to extend bilaterally between the mandibular buccal tubes and contact the inner surface of the lower lip and cheeks. It functions to eliminate the pressure on the incisors, canines, and premolars, and to transmit distally directed forces to the molars. The purpose of this study was to evaluate the short-term effects of the buccal shield modification of the lip bumper design on various mandibular dental arch parameters, as well as on the inclination of the mandibular incisors. Included in the present study were 44 consecutively treated patients, consisting of 29 females and 15 males from a private orthodontic practice. Student and paired t tests were used to evaluate the changes over time for the various measurements. The results indicated a significant (P < .0001) increase in all arch parameters measured. The greatest mean expansion was observed at the first (5.0 +/- 2.2 mm) and second (3.4 +/- 2.2 mm) premolar width measurements. Less expansion occurred in the intercanine (2.4 +/- 2.0 mm) and intermolar (2.4 +/- 2.6 mm) arch widths. Arch length increased on average 1.6 +/- 2.1 mm. These were significantly (P <.0001) greater than the normal age-related changes in the corresponding parameters.

  7. Gamma Ray Shielding Study of Barium–Bismuth–Borosilicate Glasses as Transparent Shielding Materials using MCNP-4C Code, XCOM Program, and Available Experimental Data

    Directory of Open Access Journals (Sweden)

    Reza Bagheri

    2017-02-01

    Full Text Available In this work, linear and mass attenuation coefficients, effective atomic number and electron density, mean free paths, and half value layer and 10th value layer values of barium–bismuth–borosilicate glasses were obtained for 662 keV, 1,173 keV, and 1,332 keV gamma ray energies using MCNP-4C code and XCOM program. Then obtained data were compared with available experimental data. The MCNP-4C code and XCOM program results were in good agreement with the experimental data. Barium–bismuth–borosilicate glasses have good gamma ray shielding properties from the shielding point of view.

  8. Potential of Glassy Carbon and Silicon Carbide Photonic Structures as Electromagnetic Radiation Shields for Atmospheric Re-entry

    Science.gov (United States)

    Komarevskiy,Nikolay; Shklover, Valery; Braginsky, Leonid; Hafner, Christian; Lawson, John W.

    2012-01-01

    During high-velocity atmospheric entries, space vehicles can be exposed to strong electromagnetic radiation from ionized gas in the shock layer. Glassy carbon (GC) and silicon carbide (SiC) are candidate thermal protection materials due to their high melting point and also their good thermal and mechanical properties. Based on data from shock tube experiments, a significant fraction of radiation at hypersonic entry conditions is in the frequency range from 215 to 415 THz. We propose and analyze SiC and GC photonic structures to increase the reflection of radiation in that range. For this purpose, we performed numerical optimizations of various structures using an evolutionary strategy. Among the considered structures are layered, porous, woodpile, inverse opal and guided-mode resonance structures. In order to estimate the impact of fabrication inaccuracies, the sensitivity of the reflectivity to structural imperfections is analyzed. We estimate that the reflectivity of GC photonic structures is limited to 38% in the aforementioned range, due to material absorption. However, GC material can be effective for photonic reflection of individual, strong spectral line. SiC on the other hand can be used to design a good reflector for the entire frequency range.

  9. RADIO SHIELDING PROPERTIES OF CONCRETE BASED ON SHUNGITE NANOMATERIALS

    Directory of Open Access Journals (Sweden)

    BELOUSOVA Elena Sergeevna

    2013-04-01

    Full Text Available Modifications of shielding construction materials based on Portland cement with the addition of powder nanomaterial shungite were developed. Attenuation and re­flection of electromagnetic radiation for obtained materials were studied. Recommen­dations for using are given.

  10. Reduction of entrance surface dose depending on shielding methods for panoramagraphy

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jung Hyun; Han, DongKyoon [Dept. of Radiological Science, The Graduate School, Eulji University, Sungnam (Korea, Republic of); Kim, Sung Chul [Dept. of Radiological, Science Gachon, University, Incheon (Korea, Republic of)

    2015-09-15

    Panoramagraphy was the second most used intraoral radiography utilized in Korea, resulting in 17.8% in university dental hospitals, 24.8% in dental hospitals, and 31.4% in dental clinics. Depending on increased demand like orthodontics and implant, panoromagraphy tends to consistently increase. This study were used lead glasses and lead shielding to reduce unnecessary radiation to the eyeballs and thyroid. ESD was 41.4% when radiation was shielded with the lead glasses while reducing 47.3% of ESD by shielding the X-ray tube area with shielding lead. There was no statistically significant difference. The lead glasses is appropriated to reduce unnecessary radiation exposure to the eyeballs.

  11. Physical analysis of the shielding capacity for a lightweight apron designed for shielding low intensity scattering X-rays

    National Research Council Canada - National Science Library

    Kim, Seon Chil; Choi, Jeong Ryeol; Jeon, Byeong Kyou

    2016-01-01

    The purpose of this paper is to develop a lightweight apron that will be used for shielding low intensity radiation in medical imaging radiography room and to apply it to a custom-made effective shielding...

  12. SAND IRON MORTAR WITH ADDITION OF LEAD OXIDE Pb3O4 VARIATION AS RADIATION SHIELDING OF X AND GAMMA RAYS

    Directory of Open Access Journals (Sweden)

    Yasinta Yerry Permana Sari

    2015-05-01

    The result shows that the density of sand iron and lead oxide Pb3O4 are 3,8259 and 8,4693 respectively and the unit weights are 1,965 gr/cm3 and 2,535 gr/cm3 respectively. Weight per m3 of mortar was increased caused by the increasing of lead oxide Pb3O4 on mortar. The compressive strength significantly increased starting on M2 (37,328 MPa from M1 (7,594 MPa and a bit decreased on M3 and M4, i.e. 32,188 Mpa and 30,144 Mpa respectively caused by the increase of water cement ratio. The value of water absorption was decreased as an effect of lead oxide Pb3O4 addition. From the result of Gamma radiation test, it shows that the higher the density, the higher the attenuation coefficient of the material and if the energy increases, the attenuation coefficient of the material decreases except at the energy above 1200 keV where the attenuation coefficient increases back as a result of a pair production phenomenon. The attenuation coefficient values of M1, M2, M3, and M4 are 0.102 cm-1, 0.145 cm-1, 0.152 cm-1, and 0.184 cm-1 respectively for energy 1330 keV; 0.060 cm-1, 0.104 cm-1, 0.120 cm-1, and 0.155 cm-1 respectively for energy 1170 keV; 0.157 cm-1, 0.212 cm-1, 0.242 cm-1, and 0.284 cm-1, respectively for energy 662 keV, and 0.202 cm-1, 0.309 cm-1, 0.330 cm-1, and 0.426 cm-1 respectively for energy 323 keV. The different result shows rom X ray radiation test whereas occurred inaccurate data as a result of scattering caused by wide beam owned by X ray so that the result cannot be compared with the result of Gamma radiation test. So, the results of X ray radiation test which can be used are the X ray photo of mortars that shows the homogeneity of each variable of mortar. From the effectiveness aspect as a radiation shielding, mortar M4 is the most effective because it has the biggest attenuation coefficient value.

  13. Rapid modulation of ultraviolet shielding in plants is influenced by solar ultraviolet radiation and linked to alterations in flavonoids.

    Science.gov (United States)

    Barnes, Paul W; Tobler, Mark A; Keefover-Ring, Ken; Flint, Stephan D; Barkley, Anne E; Ryel, Ronald J; Lindroth, Richard L

    2016-01-01

    The accumulation of ultraviolet (UV)-absorbing compounds (flavonoids and related phenylpropanoids) and the resultant decrease in epidermal UV transmittance (TUV ) are primary protective mechanisms employed by plants against potentially damaging solar UV radiation and are critical components of the overall acclimation response of plants to changing solar UV environments. Whether plants can adjust this UV sunscreen protection in response to rapid changes in UV, as occurs on a diurnal basis, is largely unexplored. Here, we use a combination of approaches to demonstrate that plants can modulate their UV-screening properties within minutes to hours, and these changes are driven, in part, by UV radiation. For the cultivated species Abelmoschus esculentus, large (30-50%) and reversible changes in TUV occurred on a diurnal basis, and these adjustments were associated with changes in the concentrations of whole-leaf UV-absorbing compounds and several quercetin glycosides. Similar results were found for two other species (Vicia faba and Solanum lycopersicum), but no such changes were detected in Zea mays. These findings reveal a much more dynamic UV-protection mechanism than previously recognized, raise important questions concerning the costs and benefits of UV-protection strategies in plants and have practical implications for employing UV to enhance crop vigor and quality in controlled environments. © 2015 John Wiley & Sons Ltd.

  14. The Tower Shielding Facility: Its glorious past

    Energy Technology Data Exchange (ETDEWEB)

    Muckenthaler, F.J.

    1997-05-07

    The Tower Shielding Facility (TSF) is the only reactor facility in the US that was designed and built for radiation-shielding studies in which both the reactor source and shield samples could be raised into the air to allow measurements to be made without interference from ground scattering or other spurious effects. The TSF proved its usefulness as many different programs were successfully completed. It became active in work for the Defense Atomic Support Agency (DASA) Space Nuclear Auxiliary Power, Defense Nuclear Agency, Liquid Metal Fast Breeder Reactor Program, the Gas-Cooled and High-Temperature Gas-Cooled Reactor programs, and the Japanese-American Shielding Program of Experimental Research, just to mention a few of the more extensive ones. The history of the TSF as presented in this report describes the various experiments that were performed using the different reactors. The experiments are categorized as to the programs which they supported and placed in corresponding chapters. The experiments are described in modest detail, along with their purpose when appropriate. Discussion of the results is minimal, but references are given to more extensive topical reports.

  15. Perceptions and experiences of using a nipple shield among parents and staff - an ethnographic study in neonatal units.

    Science.gov (United States)

    Flacking, Renée; Dykes, Fiona

    2017-01-03

    Preterm infants have an immature sucking behavior and the capacity to be exclusively breastfed may be reduced for a period of weeks or months, depending on gestational age. Nipple shields have been used, not only as a device to help mothers with sore nipples, but also to facilitate the infant's latch on to the breast. However, the benefits of using nipple shields have been debated. The aim of this study was to explore perceptions and experiences of using a nipple shield among parents and staff in neonatal units in Sweden and England. An ethnographic study was undertaken where observations and interviews were conducted in four neonatal units in Sweden and England. The data were analyzed using a thematic networks analysis. The global theme was developed and named, 'Nipple shield in a liminal time'. This comprised of two organizing themes: 'Relational breastfeeding' and 'Progression'. 'Relational breastfeeding' was underpinned by the basic themes, 'good enough breast', 'something in between' and 'tranquil moment'. 'Progression' was underpinned by the basic themes, 'learning quicker', 'short-term solution' and 'rescue remedy'. Although breastfeeding was seen primarily as a nutritive transaction, the relational aspects of breastfeeding were of crucial importance. These two organizing themes show the tension between acknowledging the relational aspects of breastfeeding and yet facilitating or supporting the progression of breastfeeding in the period from tube feeding or cup feeding to breastfeeding. It is a liminal time as mothers and their infants are "in between" phases and the outcome, in terms of breastfeeding, is yet to be realized. This study demonstrates parents' and staffs' perceptions of the nipple shield as a short term solution to help initiation of breastfeeding but also as a barrier between the mother and infant. It is important that the mother and baby's own particular needs are taken into account, in a person-centred way and on an ongoing basis

  16. TI8 shielding studies and angular alignment of TDI and TCDQ

    CERN Document Server

    Bartmann, W; Bracco, C; Goddard, B; Kain, V; Nordt, A

    2011-01-01

    Measurements performed to quantify the effect of the shielding installed in the TI 8 transfer line to mitigate injection losses and relative data analysis are presented in this report. Measurements of the beam size at long collimators indicated an angular misalignment of the jaws. A method to measure the jaw angle considering potential LVDT calibration errors is introduced.

  17. Applying pyrolysis-gas chromatography/mass spectrometry to the identification of oriental lacquers: study of two lacquered shields.

    Science.gov (United States)

    Frade, José Carlos; Ribeiro, Maria Isabel; Graça, José; Rodrigues, José

    2009-12-01

    Oriental lacquers have been used as coating materials for thousands of years for wooden, ceramics, leather and metal objects. Lacquers are natural polymers obtained from three species growing in different regions of Asia: Rhus vernicifera (China, Japan and Korea); Rhus succedanea (Vietnam and Taiwan); and Melanorrhoea usitate (Myanmar and Thailand). The identification of lacquer films is important for conservation and restoration purposes, as well as for art history studies because it may help in determining the origin of the lacquered objects. In this work, pyrolysis-gas chromatography/mass spectrometry using a filament-type pyrolyser was successfully applied to the characterization of oriental lacquers. A method to identify the three kinds of lacquer was developed and applied to the study of two lacquered shields imported from Asia in the sixteenth century. The materials that constitute the shields were also examined by Fourier-transform infrared microspectroscopy and details of the lacquering technique are reported.

  18. Spherical warm shield design for infrared imaging systems

    Science.gov (United States)

    Tian, Qijie; Chang, Songtao; He, Fengyun; Li, Zhou; Qiao, Yanfeng

    2017-09-01

    The F-number matching is the primary means to suppress stray radiation for infrared imaging systems. However, it is difficult to achieve exact F-number matching, owing to the restriction from detectors, or multiple F-number design. Hence, an additional shield is required to block the certain thermal radiation. Typical shield is called flat warm shield, which is flat and operates at room temperature. For flat warm shield, it cannot suppress stray radiation while achieving F-number matching. To overcome the restriction, a spherical reflective warm shield is required. First of all, the detailed theory of spherical warm shield design is developed on basis of the principle that stray radiation cannot directly reach the infrared focal plane array. According to the theory developed above, a polished spherical warm shield, whose radius is 18 mm, is designed to match an F/2 infrared detector with an F/4 infrared imaging system. Then, the performance and alignment errors of the designed spherical warm shield are analyzed by simulation. Finally, a contrast experiment between the designed spherical warm shield and two differently processed flat warm shields is performed in a chamber with controllable inside temperatures. The experimental results indicate that the designed spherical warm shield cannot only achieve F-number matching but suppress stray radiation sufficiently. Besides, it is demonstrated that the theory of spherical warm shield design developed in this paper is valid and can be employed by arbitrary infrared imaging systems.

  19. Application of Image Analysis to Identify Quartz Grains in Heavy Aggregates Susceptible to ASR in Radiation Shielding Concrete

    Directory of Open Access Journals (Sweden)

    Daria Jóźwiak-Niedźwiedzka

    2016-03-01

    Full Text Available Alkali-silica reaction (ASR is considered as a potential aging-related degradation phenomenon that might impair the durability of concrete in nuclear containments. The objective of this paper is the application of digital analysis of microscopic images to identify the content and size of quartz grains in heavy mineral aggregates. The range of investigation covered magnetite and hematite aggregates, known as good absorbers of gamma radiation. Image acquisition was performed using thin sections observed in transmitted cross-polarized light with λ plate. Image processing, consisting of identification of ferrum oxide and epoxy resin, and the subsequent application of a set of filtering operations resulted in an adequate image reduction allowing the grain size analysis. Quartz grains were classified according to their mean diameter so as to identify the reactive range. Accelerated mortar bar tests were performed to evaluate the ASR potential of the aggregates. The SiO2 content in the heavyweight aggregates determined using the image analysis of thin sections was similar to XRF test result. The content of reactive quartz hematite was 2.7%, suggesting that it would be prone to ASR. The expansion test, according to ASTM C1260, confirmed the prediction obtained using the digital image analysis.

  20. Neutron shielding and its impact on the ITER machine design

    Energy Technology Data Exchange (ETDEWEB)

    Daenner, W. (NET Team, Max-Planck-Inst. fuer Plasmaphysik, Garching (Germany)); El Guebaly, L.; Sawan, M. (Fusion Technology Inst., Univ. Wisconsin, Madison, WI (United States)); Gohar, Y. (Fusion Power Program, Argonne National Lab., IL (United States)); Maki, K. (Fusion Experimental Reactor Team, Naka Fusion Research Establishment, JAERI, Ibaraki (Japan)); Rado, V. (Associazione EURATOM-ENEA sulla Fusione, Centro Ricerche Energia, Frascati, Rome (Italy)); Schchipakin, O.; Zimin, S. (I.V. Kurchatov Inst. of Atomic Energy, Moscow (USSR))

    1991-12-01

    This paper describes the efforts made in the frame of the ITER project to analyze the shielding of the superconducting magnets. First, the radiation limits to be achieved are specified as well as the neutron source in terms of wall loading on the first wall of the machine. Then the general shield concept is explained, including the most essential details of the various shield components. A brief section is devoted to the calculational tools, the data base, and the safety factors to be applied to the results obtained. The neutronics models of four different configurations are summarized as they were used to study the most critical parts of the machine. This section is followed by a presentation of the most important results from one-, two- and three-dimensional calculations. They are given for both the reference design and an improved one in which the critical regions are reinforced with respect to their shielding capability. It is concluded that the ITER shield layout just marginally meets the stated limits provided that some tungsten is included in the critical regions. A slight revision of the overall machine dimensions with the aim to achieve a less complex shield and a higher margin with respect to the limits is, however, seen the better solution. (orig.).

  1. Dosimetric accuracy of a deterministic radiation transport based {sup 192}Ir brachytherapy treatment planning system. Part II: Monte Carlo and experimental verification of a multiple source dwell position plan employing a shielded applicator

    Energy Technology Data Exchange (ETDEWEB)

    Petrokokkinos, L.; Zourari, K.; Pantelis, E.; Moutsatsos, A.; Karaiskos, P.; Sakelliou, L.; Seimenis, I.; Georgiou, E.; Papagiannis, P. [Medical Physics Laboratory, Medical School, University of Athens, 75 Mikras Asias, 115 27 Athens (Greece); Department of Physics, Nuclear and Particle Physics Section, University of Athens, Panepistimioupolis, Ilisia, 157 71 Athens (Greece); Medical Physics Laboratory, Medical School, Democritus University of Thrace, 2nd Building of Preclinical Section, University Campus, Alexandroupolis 68100 (Greece); Medical Physics Laboratory, Medical School, University of Athens, 75 Mikras Asias, 115 27 Athens (Greece)

    2011-04-15

    Purpose: The aim of this work is the dosimetric validation of a deterministic radiation transport based treatment planning system (BRACHYVISION v. 8.8, referred to as TPS in the following) for multiple {sup 192}Ir source dwell position brachytherapy applications employing a shielded applicator in homogeneous water geometries. Methods: TPS calculations for an irradiation plan employing seven VS2000 {sup 192}Ir high dose rate (HDR) source dwell positions and a partially shielded applicator (GM11004380) were compared to corresponding Monte Carlo (MC) simulation results, as well as experimental results obtained using the VIP polymer gel-magnetic resonance imaging three-dimensional dosimetry method with a custom made phantom. Results: TPS and MC dose distributions were found in agreement which is mainly within {+-}2%. Considerable differences between TPS and MC results (greater than 2%) were observed at points in the penumbra of the shields (i.e., close to the edges of the ''shielded'' segment of the geometries). These differences were experimentally verified and therefore attributed to the TPS. Apart from these regions, experimental and TPS dose distributions were found in agreement within 2 mm distance to agreement and 5% dose difference criteria. As shown in this work, these results mark a significant improvement relative to dosimetry algorithms that disregard the presence of the shielded applicator since the use of the latter leads to dosimetry errors on the order of 20%-30% at the edge of the ''unshielded'' segment of the geometry and even 2%-6% at points corresponding to the potential location of the target volume in clinical applications using the applicator (points in the unshielded segment at short distances from the applicator). Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions and the increased attenuation involved in HDR brachytherapy applications

  2. A comparative study for different shielding material composition and beam geometry applied to PET facilities: simulated transmission curves

    Energy Technology Data Exchange (ETDEWEB)

    Hoff, Gabriela [Pontificia Univ. Catolica do Rio Grande do Sul (PUCRS), Porto Alegre, RS (Brazil). Grupo de Experimentacao e Simulacao Computacional em Fisica Medica; Costa, Paulo Roberto, E-mail: pcosta@if.usp.br [Universidade de Sao Paulo (IF/USP), SP (Brazil). Dept. de Fisica Nuclear. Lab. de Dosimetria das Radiacoes e Fisica Medica

    2013-03-15

    The aim of this work is to simulate transmission data for different beam geometry and material composition in order to evaluate the effect of these parameters on transmission curves. The simulations are focused on outgoing spectra for shielding barriers used in PET facilities. The behavior of the transmission was evaluated as a function of the shielding material composition and thickness using Geant4 Monte Carlo code, version 9.2 p 03.The application was benchmarked for barited mortar and compared to The American Association of Physicists in Medicine (AAPM) data for lead. Their influence on the transmission curves as well the study of the influence of the shielding material composition and beam geometry on the outgoing spectra were performed. Characteristics of transmitted spectra, such as shape, average energy and Half-Value Layer (HVL), were also evaluated. The Geant4 toolkit benchmark for the energy resulting from the positron annihilation phenomena and its application in transmission curves description shown good agreement between data published by American Association on Physicists in Medicine task group 108 and experimental data published by Brazil. The transmission properties for different material compositions were also studied and have shown low dependency with the considered thicknesses. The broad and narrow beams configuration presented significant differences on the result. The fitting parameter for determining the transmission curves equations, according to Archer model is presented for different material. As conclusion were defined that beam geometry has significant influence and the composition has low influence on transmission curves for shielding design for the range of energy applied to PET. (author)

  3. Comparative study between NCRP-49 and NCRP-147 methodologies for shielding calculus to fluoroscopy rooms; Estudo comparativo entre as metodologias da NCRP-49 e da NCRP-147 para calculo de blindagem para salas de fluoroscopia

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Christiano Eduardo Martins

    2011-07-01

    The walls of a fluoroscopy room must be shielded to prevent unnecessary exposures to technicians and public individuals. Thus this dissertation aims to describe the methodologies contained in two documents which are references for the calculation of shielding those rooms. They are the National Council on Radiation Protection and Measurements Report No. 49 (NCRP Report No. 49) and No. 147 (NCRP Report No. 147), the latter being more recent publication. And based on such description was made a comparative study between the two methodologies, using for this, as a benchmark, spreadsheets computer program developed by Wolfram Mathematica 6. With that we could reach the final thickness of the barriers to a Standard Plan for a fluoroscopy room (provided by Siemens) and noted that the NCRP-49 presents a methodology with results more conservative. (author)

  4. The ORNL-SNAP shielding program

    Science.gov (United States)

    Mynatt, F. R.; Clifford, C. E.; Muckenthaler, F. J.; Gritzner, M. L.

    1972-01-01

    The effort in the ORNL-SNAP shielding program is directed toward the development and verification of computer codes using numerical solutions to the transport equation for the design of optimized radiation shields for SNAP power systems. A brief discussion is given for the major areas of the SNAP shielding program, which are cross-section development, transport code development, and integral experiments. Detailed results are presented for the integral experiments utilizing the TSF-SNAP reactor. Calculated results are compared with experiments for neutron and gamma-ray spectra from the bare reactor and as transmitted through slab shields.

  5. NEUTRONIC REACTOR SHIELD AND SPACER CONSTRUCTION

    Science.gov (United States)

    Wigner, E.P.; Ohlinger, L.A.

    1958-11-18

    Reactors of the heterogeneous, graphite moderated, fluid cooled type and shielding and spacing plugs for the coolant channels thereof are reported. In this design, the coolant passages extend horizontally through the moderator structure, accommodating the fuel elements in abutting end-to-end relationship, and have access openings through the outer shield at one face of the reactor to facilitate loading of the fuel elements. In the outer ends of the channels which extend through the shields are provided spacers and shielding plugs designed to offer minimal reslstance to coolant fluid flow while preventing emanation of harmful radiation through the access openings when closed between loadings.

  6. A new polyester based polymer composite for shielding soft gamma rays

    Science.gov (United States)

    Ambika, M. R.; Nagaiah, N.; Suman, S. K.

    2017-05-01

    Finely ground particulate Tungsten Oxide filled Isophthalate Polyester based polymer composites have been fabricated for different concentrations of WO3 using a simple and well established Open mould cast technique. The gamma shielding ability of the composites was studied using a gamma ray spectrometer for 80 & 127 keV gamma rays. The shielding parameters such as linear & mass attenuation coefficients, HVL and relaxation lengths were evaluated. The linear attenuation coefficient is found to increase with increase in the density of the composites. The mass attenuation coefficient ranges from 0.162 - 2.34cm2/gm and 0.15-0.89cm2/gm for 80 & 127keV gamma rays respectively. The shielding ability of the composites increases with increase in the filler wt% and decreases with increase in energy. Thus, the novel lead free, polymer composites perform well as radiation shields and their shielding ability is comparable to lead in performance.

  7. The SHIELD11 Computer Code

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, W

    2005-02-02

    SHIELD11 is a computer code for performing shielding analyses around a high-energy electron accelerator. It makes use of simple analytic expressions for the production and attenuation of photons and neutrons resulting from electron beams striking thick targets, such as dumps, stoppers, collimators, and other beam devices. The formulae in SHIELD11 are somewhat unpretentious in that they are based on the extrapolation (scaling) of experimental data using rather simple physics ideas. Because these scaling methods have only been tested over a rather limited set of conditions--namely, 1-15 GeV electrons striking 10-20 radiation lengths of iron--a certain amount of care and judgment must be exercised whenever SHIELD11 is used. Nevertheless, for many years these scaling methods have been applied rather successfully to a large variety of problems at SLAC, as well as at other laboratories throughout the world, and the SHIELD11 code has been found to be a fast and convenient tool. In this paper we present, without extensive theoretical justification or experimental verification, the five-component model on which the SHIELD11 code is based. Our intent is to demonstrate how to use the code by means of a few simple examples. References are provided that are considered to be essential for a full understanding of the model. The code itself contains many comments to provide some guidance for the informed user, who may wish to improve on the model.

  8. Long Duration Space Shelter Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) has developed fiber reinforced ceramic composites for radiation shielding that can be used for external walls in long duration manned...

  9. Tests of shielding effectiveness of Kevlar and Nextel onboard the International Space Station and the Foton-M3 capsule.

    Science.gov (United States)

    Pugliese, M; Bengin, V; Casolino, M; Roca, V; Zanini, A; Durante, M

    2010-08-01

    Radiation assessment and protection in space is the first step in planning future missions to the Moon and Mars, where mission and number of space travelers will increase and the protection of the geomagnetic shielding against the cosmic radiation will be absent. In this framework, the shielding effectiveness of two flexible materials, Kevlar and Nextel, were tested, which are largely used in the construction of spacecrafts. Accelerator-based tests clearly demonstrated that Kevlar is an excellent shield for heavy ions, close to polyethylene, whereas Nextel shows poor shielding characteristics. Measurements on flight performed onboard of the International Space Station and of the Foton-M3 capsule have been carried out with special attention to the neutron component; shielded and unshielded detectors (thermoluminescence dosemeters, bubble detectors) were exposed to a real radiation environment to test the shielding properties of the materials under study. The results indicate no significant effects of shielding, suggesting that thin shields in low-Earth Orbit have little effect on absorbed dose.

  10. Monte carlo simulation of innovative neutron and photon shielding material composing of high density concrete, waste rubber, lead and boron carbide

    Science.gov (United States)

    Aim-O, P.; Wongsawaeng, D.; Phruksarojanakun, P.; Tancharakorn, S.

    2017-06-01

    High-density concrete exhibits high strength and can perform an important role of gamma ray attenuation. In order to upgrade this material’s radiation-shielding performance, hydrogen-rich material can be incorporated. Waste rubber from vehicles has high hydrogen content which is the prominent characteristic to attenuate neutron. The objective of this work was to evaluate the radiation-shielding properties of this composite material against neutron and photon radiations. Monte Carlo transport simulation was conducted to simulate radiation through the composite material. Am-241/Be was utilized for neutron source and Co-60 for photon source. Parameters of the study included volume percentages of waste rubber, lead and boron carbide and thickness of the shielding material. These designs were also fabricated and the radiation shielding properties were experimentally evaluated. The best neutron and gamma ray shielding material was determined to be high-density concrete mixed with 5 vol% crumb rubber and 5 vol% lead powder. This shielding material increased the neutron attenuation by 64% and photon attenuation by 68% compared to ordinary concrete. Also, increasing the waste rubber content to greater than 5% resulted in a decrease in the radiation attenuation. This innovative composite radiation shielding material not only benefits nuclear science and engineering applications, but also helps solve the environmental issue of waste rubber.

  11. VZLUSAT-1: Nanosatellite with miniature lobster eye X-ray telescope and qualification of the radiation shielding composite for space application

    Science.gov (United States)

    Urban, Martin; Nentvich, Ondrej; Stehlikova, Veronika; Baca, Tomas; Daniel, Vladimir; Hudec, Rene

    2017-11-01

    In the upcoming generation of small satellites there is a great potential for testing new sensors, processes and technologies for space and also for the creation of large in situ sensor networks. It plays a significant role in the more detailed examination, modelling and evaluation of the orbital environment. Scientific payloads based on the CubeSat technology are also feasible and the miniature X-ray telescope described in this paper may serve as an example. One of these small satellites from CubeSat family is a Czech CubeSat VZLUSAT-1, which is going to be launched during QB50 mission in 2017. This satellite has dimensions of 100 mm × 100 mm × 230 mm. The VZLUSAT-1 has three main payloads. The tested Radiation Hardened Composites Housing (RHCH) has ambitions to be used as a structural and shielding material to protect electronic devices in space or for constructions of future manned and unmanned spacecraft as well as Moon or Martian habitats. The novel miniaturized X-ray telescope with a Lobster Eye (LE) optics represents an example of CubeSat's scientific payload. The telescope has a wide field of view and such systems may be essential in detecting the X-ray sources of various physical origin. VZLUSAT-1 also carries the FIPEX payload which measures the molecular and atomic oxygen density among part of the satellite group in QB50 mission. The VZLUSAT-1 is one of the constellation in the QB50 mission that create a measuring network around the Earth and provide multipoint, in-situ measurements of the atmosphere.

  12. Pollution prevention benefits of non-hazardous shielding glovebox gloves - 11000

    Energy Technology Data Exchange (ETDEWEB)

    Cournoyer, Michael E [Los Alamos National Laboratory; Dodge, Robert L [Los Alamos National Laboratory

    2011-01-11

    Radiation shielding is commonly used to protect the glovebox worker from unintentional direct and secondary radiation exposure, while working with plutonium-238 and plutonium-239. Shielding glovebox gloves are traditionally composed of lead-based materials, i.e., hazardous waste. This has prompted the development of new, non-hazardous shielding glovebox gloves. No studies, however, have investigated the pollution prevention benefits of these new glovebox gloves. We examined both leaded and non-hazardous shielding glovebox gloves. The nonhazardous substitutes are higher in cost, but this is offset by eliminating the costs associated with onsite waste handling of Resource Conservation and Recovery Act (RCRA) items. In the end, replacing lead with non-hazardous substitutes eliminates waste generation and future liability.

  13. Dose-to-water conversion for the backscatter-shielded EPID: a frame-based method to correct for EPID energy response to MLC transmitted radiation.

    Science.gov (United States)

    Zwan, Benjamin J; King, Brian W; O'Connor, Daryl J; Greer, Peter B

    2014-08-01

    To develop a frame-by-frame correction for the energy response of amorphous silicon electronic portal imaging devices (a-Si EPIDs) to radiation that has transmitted through the multileaf collimator (MLC) and to integrate this correction into the backscatter shielded EPID (BSS-EPID) dose-to-water conversion model. Individual EPID frames were acquired using a Varian frame grabber and iTools acquisition software then processed using in-house software developed inMATLAB. For each EPID image frame, the region below the MLC leaves was identified and all pixels in this region were multiplied by a factor of 1.3 to correct for the under-response of the imager to MLC transmitted radiation. The corrected frames were then summed to form a corrected integrated EPID image. This correction was implemented as an initial step in the BSS-EPID dose-to-water conversion model which was then used to compute dose planes in a water phantom for 35 IMRT fields. The calculated dose planes, with and without the proposed MLC transmission correction, were compared to measurements in solid water using a two-dimensional diode array. It was observed that the integration of the MLC transmission correction into the BSS-EPID dose model improved agreement between modeled and measured dose planes. In particular, the MLC correction produced higher pass rates for almost all Head and Neck fields tested, yielding an average pass rate of 99.8% for 2%/2 mm criteria. A two-sample independent t-test and fisher F-test were used to show that the MLC transmission correction resulted in a statistically significant reduction in the mean and the standard deviation of the gamma values, respectively, to give a more accurate and consistent dose-to-water conversion. The frame-by-frame MLC transmission response correction was shown to improve the accuracy and reduce the variability of the BSS-EPID dose-to-water conversion model. The correction may be applied as a preprocessing step in any pretreatment portal dosimetry

  14. Intercalated and Hydrogenated Carbon Nanofibers for Multifunctional Radiation Protection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Improvements in radiation shielding materials are needed to support NASA's human and robotic exploration programs. Shielding for both electromagnetic radiation...

  15. THEORETICAL STUDY OF SOLVENT EFFECTS AND NMR SHIELDING TENSORS OF DLPC

    Directory of Open Access Journals (Sweden)

    M. Monajjemi

    2010-06-01

    Full Text Available The effect of the polarity of the environment on the conformation zwitterionic membrane dilauroyl phosphatidylcholine (DLPC has been investigated with calculation at the Hatree-Fock level using the 6-31G* basis set with Onsager continuum solvation model. The ‘Gauge Including Atomic Orbital' (GIAO approach is used to investigate Ab initio GIAO calculations of NMR chemical shielding tensors carried out within SCF-Hartree-Fock approximation are described. In order to compare the calculated chemical shifts with experimental ones, it is important to use consistent nuclear shielding for NMR reference compounds like TMS. Conformation of DLPC was evaluated with four different solvents with different dielectric constant (Water (ε = 78.39, Dimethyl Sulfoxide (ε = 46.7, Acetone (ε = 20.7 and Heptane (ε = 1.92. In concern with conformational energy, Water could be the most suitable solvent for DLPC. Moreover, as the polarity of the medium increase, the conformational stability of this molecule increases faster than that of DLPC in the gas phase. Consequently, the relative energy of DLPC also depends on the polarity of the environment. This subject was considered as well as the most variable in some dihedral angles degree and NMR isotropic shift were in the less dielectric constant (ε = 1.92. It could be in polar medium DLPC conformer becomes additionally stabilized by intermolecular ionic and hydrogen bond interactions with polar neighboring molecules. On the basis of this work it can be concluded that the effect of the polarity of the environment clearly are influenced on the isotropic values by geometry variation due to intermolecular motion in molecule.   Keywords: Onsager continuum model, DLPC ,NMR shielding, isotropic, solvent models, anisotropic

  16. Study of the shielding and the doses of the radiotherapy installation of the Instituto Zacatecano del Tumor; Estudio del blindaje y las dosis de la instalacion de radioterapia del Instituto Zacatecano del Tumor

    Energy Technology Data Exchange (ETDEWEB)

    Davila C, S.; Mireles G, F.; Davila R, J. I.; Rios M, C.; Pinedo V, J. L., E-mail: dacis84@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2012-10-15

    The radiotherapy is the use of the ionizing radiations for treatment of several cancer types. The radiotherapy equipment s are situated inside an installation specially designed to offer attention to the patients and appropriate radiological protection of the occupational exposed personnel and the public in general. For this reason is necessary to evaluate the behavior of the shielding of the radiotherapy room of the Instituto Zacatecano del Tumor located in the Zacatecas city. Accumulated dose measurements were made in a work day of the radiotherapy room in the interest points using solid state dosimeters, considering the number of attended patients, the applied treatments and the discharges number. Also the simulation of the radiation gamma transport in the room was realized by means of Monte Carlo method with the MCNP5 code to compare the results. In the measurement points of the exterior of room the doses are practically similar to those of the bottom of natural radiation, what means that the shielding of the room is fulfilling its function. In the measurement points located inside the room we find higher dose and with more risk for the health. It is important to carry out this type of studies to guarantee the radiological protection of the occupational exposed personnel and the public in general. With these studies we can establish that so much is possible to increase or to reduce the work load in a radiotherapy room. (Author)

  17. Radiation Storm vs. The Magnetic Shield: Superheroes of Magnetism & Space Weather Education - A Model for Teacher Professional Development Workshops

    Science.gov (United States)

    Russell, R. M.; Johnson, R. M.

    2010-12-01

    Magnetic and electric fields and phenomena play important roles in various situations in astronomy, planetary science, and Earth science. Students often lack an intuitive sense of electromagnetic phenomena, and therefore struggle with the complexities of planetary and stellar magnetic fields. Hands-on magnetism activities can provide students with an intuitive grasp of the basics of magnetism, preparing them for more challenging conceptual studies of magnetic phenomena. For the past six years, we have been presenting a professional development workshop for teachers covering the topics of magnetism and space weather. The workshop, which has been conducted more than 20 times for a range of audiences, blends together several simple hands-on activities, background information on space weather and geomagnetism, a collection of images, animations, and interactives that illustrate important concepts, and guidance about specific links between these topics and national science education standards. These workshops have been very well-received, and have consistently been rated highly by participants in surveys. We believe the methods used in these workshops can be applied to other topics in science education and to astronomy and Earth science education specifically. In this presentation, we will describe our magnetism and space weather workshop, including some of the hands-on activities. We will describe successful aspects of the workshop and comment on ways we think this approach could be replicated for other topics. We will also display some of the interactives, graphics, and animations shown during the workshops. Resources have been added to the workshop over the years in response to recurring questions from teachers; we will comment on this process and how it might be applied to other topics. The activities and extensive background content used or referenced in the workshop are available for free on the Windows to the Universe web site (www.windows2universe.org). Hands on

  18. Comparison between Clinically Used Irregular Fields Shielded by Cerrobend and Standard Lead Blocks

    Directory of Open Access Journals (Sweden)

    Farajollahi A. R.

    2015-06-01

    Full Text Available Introduction: In radiation therapy centers across Iran, protection of normal tissues is usually accomplished by either Cerrobend or lead block shielding. In this study, the influence of these two shielding methods on central axis dose distribution of photon beam a Cobalt unit was investigated in clinical conditions. Materials and Methods: All measurements were performed for 60Co γ-ray beams and the Cerrobend blocks were fabricated by commercial Cerrobend materials. Standard lead block shields belonged to Cobalt unit. Data was collected through a calibrated ionization chamber, relative dosimetry systems and a TLD dosimetery. Results: Results of the percent depth dose (PDD measurements at depths of 0.5, 1, 5, 10, 15 and 20 cm for 23 different field sizes of patients with head and neck cancer showed no significant differences between lead and Cerrobend shielding methods. Measurement results of absolute dosimetry in depths of 1.5, 3, 5, 7, 10 and 12 cm also showed no significant differences between these two shielding methods. The same results were obtained by TLD dosimetry on patient skin. Conclusion: Use of melt shielding methods is a very easy and fast shield-making technique with no differences in PDD, absolute and skin dose between lead and Cerrobend block shielding methods.

  19. Parametric study for use of stainless steel as a material for thermal shield in PIP2IT transferline at Fermilab

    Science.gov (United States)

    Rane, Tejas; Chakravarty, Anindya; Klebaner, Arkadiy

    2017-12-01

    Transferline thermal shields are cooled by dedicated cooling lines welded/brazed to the shield at a single point along the circumference. Copper/Aluminium is widely used to fabricate thermal shields because of their higher thermal diffusivity. This causes uniformity of temperature along the surface of the shield thus reducing thermal stresses within allowable values. However, factors such as raw material price, the cost of fabrication depending on standard sizes of pipes/tubes, often drives up the final price of thermal shields. To reduce the cost by making use of easily available stock of standard pipe/tube, it is decided to use stainless steel as a material for thermal shields in the PIP2IT transferline. The present paper discusses the design approach, various factors affecting the conservative selection of thermal shield design.

  20. Characterization of barite and crystal glass as attenuators in X-ray and gamma radiation shieldings; Caracterizacao da barita e do vidro cristal como atenuadores na blindagem das radiacoes X e gama

    Energy Technology Data Exchange (ETDEWEB)

    Almeida Junior, Airton Tavares de

    2005-03-15

    Aiming to determine the barium sulphate (BaSO{sub 4}) ore and crystal glass attenuation features, both utilized as shieldings against ionizing X and gamma radiations in radiographic installations, a study of attenuation using barite plaster and barite concrete was carried out, which are used, respectively, on wall coverings and in block buildings. The crystal glass is utilized in screens and in windows. To do so, ten plates of barite plaster and three of barite concrete with 900 cm{sup 2} and with an average thickness ranging from 1 to 5 cm, and three plates of crystal glass with 323 cm{sup 2} and with thicknesses of 1, 2 and 4 cm were analyzed. The samples were irradiated with X-rays with potentials of 60, 80, 110 and 150 kilovolts, and also with {sup 60}Co gamma rays. Curves of attenuation were obtained for barite plaster and barite concrete (mGy/mA.min) and (mGy/h), both at 1 meter, as a function of thickness and curve of transmission through barite plaster and barite concrete as a function of the thickness. The equivalent thicknesses of half and tenth value layers for barite plaster, barite concrete and crystal glass for all X-Ray energies were also determined. (author)

  1. Experimental and numerical study of the pressure drop for ITER blanket shield block

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Min-Su; Kim, Sawoong; Jung, Hun-Chea; Shim, Hee-Jin; Ahn, Hee-Jae

    2016-11-01

    Highlights: • The results of the experiment and the numerical analysis are compared. • The numerical analysis results are lower than the experimental results. • The margin of the pressure drop is suggested. - Abstract: The blanket shield block (SB) is located inside the ITER vacuum chamber, and the main function is to provide the thermal and nuclear shielding to the vacuum vessel and external components. The SB is foreseen to undergo a significant heat load which is a body load throughout the whole thickness of the SB under normal operation conditions. Therefore, the cooling configuration in SB should be designed very carefully based on the various experiences. The pressure drop in the cooling design is one of the most important factors to balance a water distribution of overall blanket cooling system. In order to verify the pressure drop characteristic and validate the design methodology of SB, experiment and numerical analysis are performed and compared their results. These results would be a benchmarking of the numerical results with experimental results to assess the gap between calculations and experiments.

  2. EMI shielding performance study of tri-layer nano stealth composites

    Science.gov (United States)

    Song, Di; Liu, Yanju; Leng, Jinsong

    2010-04-01

    In this paper, a method for preparing tri-layer nano stealth composite film is proposed. Using H2SO4, HNO3 mixture for MWCNTs carboxylation, dispersant CTAB is added into surface-treated CNTs, nano Fe and nano Fe3O4 respectively. These three mixtures are dispersed by ultrasonic vibration so that they form homogeneous films in epoxy matrix. Vector network analyzer is utilized for EMI SE measurements. According to experiment data, EMI shielding performance curves are generated when CNTs vary from 5%-10%wt, nano Fe 10%-15%wt, nano Fe3O4 10%-15%wt respectively in the frequency bands of 3.22-40GHz. Simultaneously, variation trends of these curves are analyzed. A new type of multilayer nano stealth composite film is fabricated by superposing the three films prepared above. The tri-layer nanocomposites of which matching layer of is 15%wt nano Fe3O4 or 15%wt nano Fe, absorbing layer is 5%wt CNTs and reflecting layer is 10%wt CNTs has good EMI shielding performance. The peak values of the two layered material all achieve more than -100dB.

  3. SHIELDS Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Jordanova, Vania Koleva [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-03

    Predicting variations in the near-Earth space environment that can lead to spacecraft damage and failure, i.e. “space weather”, remains a big space physics challenge. A new capability was developed at Los Alamos National Laboratory (LANL) to understand, model, and predict Space Hazards Induced near Earth by Large Dynamic Storms, the SHIELDS framework. This framework simulates the dynamics of the Surface Charging Environment (SCE), the hot (keV) electrons representing the source and seed populations for the radiation belts, on both macro- and micro-scale. In addition to using physics-based models (like RAM-SCB, BATS-R-US, and iPIC3D), new data assimilation techniques employing data from LANL instruments on the Van Allen Probes and geosynchronous satellites were developed. An order of magnitude improvement in the accuracy in the simulation of the spacecraft surface charging environment was thus obtained. SHIELDS also includes a post-processing tool designed to calculate the surface charging for specific spacecraft geometry using the Curvilinear Particle-In-Cell (CPIC) code and to evaluate anomalies' relation to SCE dynamics. Such diagnostics is critically important when performing forensic analyses of space-system failures.

  4. The LVD Core Facility: a study of LVD as muon veto and active shielding for dark matter experiments

    CERN Document Server

    Selvi, Marco

    2008-01-01

    In this study we explore the possibility of using the existing structure of a running experiment, the LVD supernova observatory at the INFN Gran Sasso National Laboratory, as an active shield and veto for the muon-induced background. In our vision LVD could become (without affecting in any way its main purpose of SN neutrino telescope) a host for a relatively compact but massive experiment looking for rare events. The empty volume that can be obtained removing 2 modules from the most internal part of the detector is 2.1m x 6.2m x 2.8m; we will call it LVD Core Facility (LVD-CF). We have evaluated the active vetoing and shielding power of LVD, with a detailed MC simulation (based on Geant4) of the detector and the rock that surrounds it. The results show that the flux of neutrons that are not associated with a visible muon in LVD is very low; it results reduced by a factor 50, equivalent to the one present in a much deeper underground laboratory, i.e. Sudbury. Moreover we present the results of on-going measur...

  5. Studies of the hemolytic effect of radiation

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, S.; Katz, E.; Porter, L.M.; Jacobson, L.O.; Watson, C.J.

    1945-07-10

    These studies were aimed at elucidating affects of radiation in inducing hemolysis independent of inhibition of erythropoiesis. Research studies were conducted both on human patients and dogs. Phosphorus-32 in mc amounts were administered either intravenously or orally to patients suffering Polycythemia rubra vera. Dogs were treated with either P-32 or x-radiation. Hemoglobin metabolism was monitored in all test subjects by hematology, blood chemistry, and fecal excretion of hemoglobin catabolites.

  6. Vehicle Shield Optimization and Risk Assessment of Future NEO Missions

    Science.gov (United States)

    Nounu, Hatem, N.; Kim, Myung-Hee; Cucinotta, Francis A.

    2011-01-01

    Future human space missions target far destinations such as Near Earth Objects (NEO) or Mars that require extended stay in hostile radiation environments in deep space. The continuous assessment of exploration vehicles is needed to iteratively optimize the designs for shielding protection and calculating the risks associated with such long missions. We use a predictive software capability that calculates the risks to humans inside a spacecraft. The software uses the CAD software Pro/Engineer and Fishbowl tool kit to quantify the radiation shielding properties of the spacecraft geometry by calculating the areal density seen at a certain point, dose point, inside the spacecraft. The shielding results are used by NASA-developed software, BRYNTRN, to quantify the organ doses received in a human body located in the vehicle in a possible solar particle events (SPE) during such prolonged space missions. The organ doses are used to quantify the risks posed on the astronauts' health and life using NASA Space Cancer Model software. An illustration of the shielding optimization and risk calculation on an exploration vehicle design suitable for a NEO mission is provided in this study. The vehicle capsule is made of aluminum shell, airlock with hydrogen-rich carbon composite material end caps. The capsule contains sets of racks that surround a working and living area. A water shelter is provided in the middle of the vehicle to enhance the shielding in case of SPE. The mass distribution is optimized to minimize radiation hotspots and an assessment of the risks associated with a NEO mission is calculated.

  7. Characterization of a lead breast shielding for dose reduction in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Correia, Paula Duarte; Brochi, Marco Aurelio Corte; Azevedo-Marques, Paulo Mazzoncini de, E-mail: pauladuarte@usp.br [Universidade de Sao Paulo (FM/RSP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina; Granzotti, Cristiano Roberto Fabri; Santos, Yago da Silva [Universidade de Sao Paulo (FFCLRP/RSP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras

    2014-07-15

    Objective: several studies have been published regarding the use of bismuth shielding to protect the breast in computed tomography (CT) scans and, up to the writing of this article, only one publication about barium shielding was found. The present study was aimed at characterizing, for the first time, a lead breast shielding. Materials and methods: the percentage dose reduction and the influence of the shielding on quantitative imaging parameters were evaluated. Dose measurements were made on a CT equipment with the aid of specific phantoms and radiation detectors. A processing software assisted in the qualitative analysis evaluating variations in average CT number and noise on images. Results: the authors observed a reduction in entrance dose by 30% and in CTDIvol by 17%. In all measurements, in agreement with studies in the literature, the utilization of cotton fiber as spacer object reduced significantly the presence of artifacts on the images. All the measurements demonstrated increase in the average CT number and noise on the images with the presence of the shielding. Conclusion: as expected, the data observed with the use of lead shielding were of the same order as those found in the literature about bismuth shielding. (author)

  8. Results of the neotectonic stress state study in the eastern part of Baltic shield

    Science.gov (United States)

    Sim, Lidiya A.; Zhirov, Dmitriy V.; Smaglichenko, Tatyana A.; Smaglichenko, Alexandr V.

    2010-05-01

    Recently a caving of the Kovdor quarry south-eastern bort occurred on the Kovdor massif (the eastern part of Baltic shield). This required a careful analyze of the stress field in the massif and a comparison of it with general situation in a region. In spite of weak seismicity at whole on the given territory it is characterized by the presence of earthquakes with M = 4 - 4.4 especially in zones of mining works (for example, events of 16.04.1989 and 17.08.1999 at the Khibiny-Lovoserskyi district). The risk zone is increased as for large industrial facilities AES located there as for big quarries extracting minerals. Kinematic method developed by Gushenko in 1973, 1979 has been applied in order to get the stress fields. The field works were performed during summer of 2009. According to this method vectors of tectonic movements along in fissures have been analyzed and local stress states have been reconstructed demonstrating significant range in orientation of axis of main normal stresses. These local stress states were conventionally correspond to the third rank and by using this information tectonic stresses of the second rank have been reconstructed. In the caving zone the local stress state can be characterized as uniaxial tension that could bring the caving. Previous investigations of the eastern part of Baltic shield were made for peninsulas Sredniy, Ryibachiy, for the White sea islands, at coast of the Kandalakschsky Bay, on the Chibino massif. Tectonic stresses of the first rank were revealed and were characterized as subhorizontal axis of compression and of tension. The compressional axis has the WNW orientation while and the extension axis is submeridional. Our research showed that the compression axis on the Kovdor massif has orientation 98° , angle is equal 15. This is in agreement with the previous results. The reconstructed stress field at whole well corresponds to the major faults Onego-Segozerskiy and Kandalakscha, which are seismic active zones. The

  9. Mathematical modeling of the radiation dose received from photons passing over and through shielding walls in a PET/CT suite

    DEFF Research Database (Denmark)

    Fog, Lotte S; Cormack, John

    2010-01-01

    as transmission through these barriers is taken into account. A series of simulations of the dose received by a person positioned behind a shielding barrier in a typical PET/CT scanning suite were carried out using both Monte Carlo and analytical models. The transmission through lead barriers was found to be very...

  10. Influence study of the barite mortar composition on shielding thickness for diagnostic radiology energies;Estudo da influencia da composicao da argamassa baritada na espessura da blindagem para energias do radiodiagnostico

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Wedla P. de; Hoff, Gabriela [Pontificia Univ. Catolica do Rio Grande do Sul (PUC/RS), Porto Alegre, RS (Brazil). Faculdade de Fisica

    2009-07-01

    The photons transmission is one of the used parameters for calculate the shielding material thickness. Using the computational simulation method purposed in this work was generated transmission curves for different energies for monoenergetic beams, on diagnostic radiology range, for values between 60 and 150 keV, in steps of 10 keV, to verify this way the sensitivity of the beam radiation to the differences on barite mortar composition. The computational universe generated simulated a primary beam radiation irradiating directly the shielding wall, and the barite composition was defined base on an sample analyzed using the energy dispersion spectroscopy (EDS) measurements in a Philips XL 30 Scanning Electron Microscope (SEM). The composition was analyzed for different sample areas, four different compositions for the same sample: one on open field view and three using focused field view. Was possible verify significant differences on transmission curves for the different studied energies and different compositions of barite mortar. We suggest futures works to study realistic spectra for different barite mortar compositions commercialized in Brazil. (author)

  11. Was the Dalkon Shield a safe and effective intrauterine device? The conflict between case-control and clinical trial study findings.

    Science.gov (United States)

    Mumford, S D; Kessel, E

    1992-06-01

    To compare the findings of the case-control and cohort studies used to indict the Dalkon Shield (A.H. Robins Company, Inc., Richmond, VA) with the findings of the Dalkon Shield clinical trials. All published reports on the Dalkon Shield were identified through MEDLARS system (United States National Library of Medicine) searches and by cross checking all references in these reports. The same approach was used to identify all case-control and cohort studies of the purported relationship between intrauterine devices (IUDs) and pelvic inflammatory disease (PID). Only studies of interval patients that included 50 or more women and 6 or more months of follow up that computed standard IUD event rates (rates of pregnancy and expulsion and removal for pain and bleeding) were selected for this study. All case-control and cohort studies identified were included except two case-control studies that included women with sterile chronic salpingitis. The 16 case-control and 2 cohort studies found or suggested that the Dalkon Shield increased the risk of PID. The 71 clinical trials of the Dalkon Shield show that when this device is inserted by an experienced clinician it is a safe and effective contraceptive method, comparable with other IUDs used at the time. There was no evidence of an increased risk of PID found in these clinical trials. This study offers convincing evidence that the indictment of the Dalkon Shield was a mistake. Additionally, this study shows that physician skill and experience is far more important to successful IUD insertion than previously recognized, a finding with considerable implications for IUD study designs and for marketing strategies.

  12. Shielding Structures for Interplanetary Human Mission

    Science.gov (United States)

    Tracino, Emanuele; Lobascio, Cesare

    2012-07-01

    Since the end of Apollo missions, human spaceflight has been limited to the Low Earth Orbit (LEO), inside the protective magnetic field of the Earth, because astronauts are, to the largest degree, protected from the harsh radiation environment of the interplanetary space. However, this situation will change when space exploration missions beyond LEO will become the real challenge of the human exploration program. The feasibility of these missions in the solar system is thus strongly connected to the capability to mitigate the radiation-induced biological effects on the crew during the journey and the permanence on the intended planet surface. Inside the International Space Station (ISS), the volumes in which the crew spends most of the time, namely the crew quarters are the only parts that implement dedicated additional radiation shielding made of polyethylene tiles designed for mitigating SPE effects. Furthermore, specific radiation shielding materials are often added to the described configuration to shield crew quarters or the entire habitat example of these materials are polyethylene, liquid hydrogen, etc. but, increasing the size of the exploration vehicles to bring humans beyond LEO, and without the magnetosphere protection, such approach is unsustainable because the mass involved is a huge limiting factor with the actual launcher engine technology. Moreover, shielding against GCR with materials that have a low probability of nuclear interactions and in parallel a high ionizing energy loss is not always the best solution. In particular there is the risk to increase the LET of ions arriving at the spacecraft shell, increasing their Radio-Biological Effectiveness. Besides, the production of secondary nuclei by projectile and target fragmentation is an important issue when performing an engineering assessment of materials to be used for radiation shielding. The goal of this work is to analyze different shielding solutions to increase as much as possible the

  13. Study on external beam radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Mi Sook; Yoo, Seoung Yul; Yoo, Hyung Jun; Ji, Young Hoon; Lee, Dong Han; Lee, Dong Hoon; Choi, Mun Sik; Yoo, Dae Heon; Lee, Hyo Nam; Kim, Kyeoung Jung

    1999-04-01

    To develop the therapy technique which promote accuracy and convenience in external radiation therapy, to obtain the development of clinical treatment methods for the global competition. The contents of the R and D were 1. structure, process and outcome analysis in radiation therapy department. 2. Development of multimodality treatment in radiation therapy 3. Development of computation using networking techniques 4. Development of quality assurance (QA) system in radiation therapy 5. Development of radiotherapy tools 6. Development of intraoperative radiation therapy (IORT) tools. The results of the R and D were 1. completion of survey and analysis about Korea radiation therapy status 2. Performing QA analysis about ICR on cervix cancer 3. Trial of multicenter randomized study on lung cancers 4. Setting up inter-departmental LAN using MS NT server and Notes program 5. Development of ionization chamber and dose-rate meter for QA in linear accelerator 6. Development on optimized radiation distribution algorithm for multiple slice 7. Implementation on 3 dimensional volume surface algorithm and 8. Implementation on adaptor and cone for IORT.

  14. Radiation area monitor device and method

    Energy Technology Data Exchange (ETDEWEB)

    Vencelj, Matjaz; Stowe, Ashley C.; Petrovic, Toni; Morrell, Jonathan S.; Kosicek, Andrej

    2018-01-30

    A radiation area monitor device/method, utilizing: a radiation sensor; a rotating radiation shield disposed about the radiation sensor, wherein the rotating radiation shield defines one or more ports that are transparent to radiation; and a processor operable for analyzing and storing a radiation fingerprint acquired by the radiation sensor as the rotating radiation shield is rotated about the radiation sensor. Optionally, the radiation sensor includes a gamma and/or neutron radiation sensor. The device/method selectively operates in: a first supervised mode during which a baseline radiation fingerprint is acquired by the radiation sensor as the rotating radiation shield is rotated about the radiation sensor; and a second unsupervised mode during which a subsequent radiation fingerprint is acquired by the radiation sensor as the rotating radiation shield is rotated about the radiation sensor, wherein the subsequent radiation fingerprint is compared to the baseline radiation fingerprint and, if a predetermined difference threshold is exceeded, an alert is issued.

  15. Potential Polymeric Sphere Construction Materials for a Spacecraft Electrostatic Shield

    Science.gov (United States)

    Smith, Joseph G., Jr.; Smith, Trent; Williams, Martha; Youngquist, Robert; Mendell, Wendell

    2006-01-01

    An electrostatic shielding concept for spacecraft radiation protection under NASA s Exploration Systems Research and Technology Program was evaluated for its effectiveness and feasibility. The proposed shield design is reminiscent of a classic quadrupole with positively and negatively charged spheres surrounding the spacecraft. The project addressed materials, shield configuration, power supply, and compared its effectiveness to that of a passive shield. The report herein concerns the identification of commercially available materials that could be used in sphere fabrication. It was found that several materials were needed to potentially construct the spheres for an electrostatic shield operating at 300 MV.

  16. Evaluation of the efficiency of bismuth breast shield in CT chest paediatric examinations; Valoracion en el paciente pediatrico de la eficacia de los protectores de bien procedimientos de TC de torax con sistemas de control automatico de intensidad

    Energy Technology Data Exchange (ETDEWEB)

    Sevillano, D.; Espana, M. L.; Castro, P.; Minguez, C.; Albi, G.; Garcia, E.; Lopez Franco, P.

    2006-07-01

    The aim of this study is to evaluate the efficiency of bismuth breast shield in CT chest paediatric examinations when automatic exposure control techniques are used. The influence in the radiation dose and the image quality has been evaluated with and without the breast shield in the scoutview. In addition the radiation dose in shielded and non-shielded areas has been compared. Measurements were made in a 16 cm diameter cylindrical PMMA phantom simulating a newborn, and older children were simulated controlling the maximum intensities allowed by the automatic exposure control system AutomA. The highest dose reduction (59%) was obtained with AutomA system and when the breast shield is not used in the scoutview. This reduction in the radiation dose does not mean a significant increase of noise level. The use of the breast shield in the scoutview yielded an increase in the radiation dose in non-shielded areas. The use of bismuth breast shield is recommended only after the scoutview in order to optimise the radiation dose in CT chest paediatric examination when using automatic exposure control AutomA. (Author)

  17. Permittivity and Electromagnetic Interference Shielding Investigations of Activated Charcoal Loaded Acrylic Coating Compositions

    Directory of Open Access Journals (Sweden)

    Sharief ud Din Khan

    2014-01-01

    Full Text Available Acrylic resin (AR based electromagnetic interference (EMI shielding composites have been prepared by incorporation of up to 30 wt% activated charcoal (AC in AR matrix. These composites have been characterized by XRD, Raman spectroscopy, scanning electron microscopy, dielectric, and EMI shielding measurement techniques. XRD patterns and Raman studies confirm the incorporation of AC particles inside AR matrix and suggest possible interactions between phases. The SEM images show that incorporation of AC particles leads to systematic change in the morphology of composites especially the formation of porous structure. The dielectric measurements show that 30 wt% AC loading composite display higher relative permittivity value (~79 compared to pristine AR (~5. Further, the porous structure, electrical conductivity, and permittivity value contribute towards EMI shielding effectiveness value of −36 dB (attenuation of >99.9% of incident radiation for these composites, thereby demonstrating their suitability for making efficient EMI shielding coatings.

  18. Study of the workload to be applied in the shielding calculation in HDR brachytherapy facilities with IR-192; Estudio de la carga de trabajo a aplicar en el calculo de blindajes en instalaciones de braquiterapia HDR con IR-192

    Energy Technology Data Exchange (ETDEWEB)

    Pujades-Clamarchirant, M. C.; Perez-Calatayud, J.; Ballester, F.; Gimeno, J.; Granero, D.; Camacho, C.; Carmona, V.; Lliso, F.; Vijande, J.

    2011-07-01

    The design of shielding facilities high rate brachytherapy (HDR) requires an estimate of the workload (w) . The aim of this study was to evaluate the W typical service HDR BT with a high number of applications and their impact on the final thickness the shielding of the room. To do this, a review of patients treated in our center HDR W has been evaluated and studied their impact on the shielding design of the facility.

  19. Study of structure and dynamics of shielding layer for inclined incidence of plasma stream at MK-200 facility

    Energy Technology Data Exchange (ETDEWEB)

    Arkhipov, N.I. [Troitsk Inst. for Innovation and Fusion Res. (Russian Federation); Bakhtin, V.P. [Troitsk Inst. for Innovation and Fusion Res. (Russian Federation); Kurkin, S.M. [Troitsk Inst. for Innovation and Fusion Res. (Russian Federation); Safronov, V.M. [Troitsk Inst. for Innovation and Fusion Res. (Russian Federation); Toporkov, D.A. [Troitsk Inst. for Innovation and Fusion Res. (Russian Federation); Vasenin, S.G. [Troitsk Inst. for Innovation and Fusion Res. (Russian Federation); Wuerz, H. [Forschungszentrum Karlsruhe (Germany); Zhitlukhin, A.M. [Troitsk Inst. for Innovation and Fusion Res. (Russian Federation)

    1996-10-01

    Results of the first disruption simulation experiment under plasma stream power density of 30-40 MW/cm{sup 2} are presented. POCO and RGT graphite were exposed to perpendicular and inclined incidence of hydrogen plasma stream with energy density up to 1.4 kJ/cm{sup 2}, directed ion energy of 2-3 keV in the presence of magnetic field up to 3.3 T. Optical interferometry and soft X-ray spectroscopy were employed for analysis of target plasma. Contrary to well studied perpendicular plasma impact the inclined plasma incidence results in a drift of target plasma along the sample surface. This restricts the plasma shield effect and increases the erosion rate. (orig.).

  20. Shielding analysis in the design phase of the new Emergency Operation Facility for Tihange Nuclear Power Plant

    Science.gov (United States)

    Genard, Gilles; Portal, Romain; Bouchat, Virginie; Vanderperre, Serge

    2017-09-01

    In the framework of the design studies for a new Emergency Operation Facility (EOF) for Tihange NPP, radiation protection analyses are needed to comply with effective dose rate criteria. In this aim, the shielding performed by, at the one hand, external walls and roof of the building and, on the other hand, internal walls, has been sized by means of MicroShield calculations. This paper explains how the calculations for external walls, doors, roof, floor and internal walls are made. The assumptions on the source terms and on the source geometry as well as the way the shielding is determined and the results of the sizing are presented.

  1. Shielding analysis in the design phase of the new Emergency Operation Facility for Tihange Nuclear Power Plant

    Directory of Open Access Journals (Sweden)

    Genard Gilles

    2017-01-01

    Full Text Available In the framework of the design studies for a new Emergency Operation Facility (EOF for Tihange NPP, radiation protection analyses are needed to comply with effective dose rate criteria. In this aim, the shielding performed by, at the one hand, external walls and roof of the building and, on the other hand, internal walls, has been sized by means of MicroShield calculations. This paper explains how the calculations for external walls, doors, roof, floor and internal walls are made. The assumptions on the source terms and on the source geometry as well as the way the shielding is determined and the results of the sizing are presented.

  2. Study on radiation-inducible genes

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sang Yong; Kim, Dong Ho; Joe, Min Ho; Song, Hyu Npa

    2012-01-15

    Transcription of previously identified radiation-inducible genes, uscA and cyoA, was examined responding to radiation. The putative promoter regions of both genes were cloned into pRS415 vector containing lacZ, and the core promoter region necessary for radiation response were determined through promoter deletion method. To investigate the role of uscA, which is assumed to be small RNA related with radiation response, a deletion mutant strain of uscA was constructed. However, uscA deletion did not affect bacterial survival against radiation exposure. The use of bacteria as anticancer agents has attracted interest. In this study, we tried to develop tumor targeting bacteria in which the radiation-inducible promoter activate a transgene encoding a cytotoxic protein. For outward secretion of anticancer protein produced inside bacteria, the N-terminal 140 amino acid of SspH1 was found to function as a secretion signal peptide. To create an attenuated tumor-targeting bacteria, Salmonella ptsI mutant strain was constructed, and we found that its virulence decreased. Finally, the tumor-targeting ability of ptsI mutant was verified by the use of in-vivo imaging analysis.

  3. The fundamental study to control the magnetic field for MDDS using shielding currents of HTS tapes and bulks

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.B., E-mail: kim@ec.okayama-u.ac.jp; Eritate, I.; Abe, T.; Shima, S.; Takahashi, M.

    2014-11-15

    Highlights: • MDDS is a key technology to reduce the side effects. • The field control method for MDDS was studied using HTS tapes and bulks. • The shielding current due to Meissner effect was used to generate the field gradient. • HTS bulks and films were combined with iron blocks, and they are very effective. • The magnetic field gradient which is higher than the external field was obtained. - Abstract: The magnetic drug delivery system (MDDS) is a key technology to reduce the side effects in the medical applications, and the magnetic force control is a very important issue in MDDS. In general, the high magnetic field along the axial direction and high magnetic field gradient along the longitudinal direction are very useful for MDDS. So, we proposed the new magnetic force control system that consists of superconducting magnet, high temperature superconductors (HTS) bulks or tapes and ferromagnetic substances. In this new system, the shielding currents in HTS bulks and tapes due to diamagnetism of the superconductor generate the magnetic field with same direction of external magnetic field, and we can control the magnetic field gradient along the longitudinal direction by the arrangement of the HTS bulks, tapes and ferromagnetic substances. In this study, the stacked GdBCO tapes without stabilizer were used in experiments and electromagnetic analysis based on finite element method (FEM) was carried out to optimize the arrangement of the superconductors and the irons. It was confirmed that the control of magnetic field gradient along the longitudinal direction was possible by arranging the HTS bulks, tapes and irons on the superconducting magnet and then it was possible to obtain a magnetic field higher than the external field.

  4. The Active Muon Shield

    CERN Document Server

    Bezshyiko, Iaroslava

    2016-01-01

    In the SHiP beam-dump of the order of 1011 muons will be produced per second. An active muon-shield is used to magnetically deflect these muons out of the acceptance of the spectrom- eter. This note describes how this shield is modelled and optimized. The SHiP spectrometer is being re-optimized using a conical decay-vessel, and utilizing the possibility to magnetize part of the beam-dump shielding iron. A shield adapted to these new conditions is presented which is significantly shorter and lighter than the shield used in the Technical Proposal (TP), while showing a similar performance.

  5. Theoretical Study of H/D Isotope Effects on Nuclear Magnetic Shieldings Using an ab initio Multi-Component Molecular Orbital Method

    Directory of Open Access Journals (Sweden)

    Masanori Tachikawa

    2013-05-01

    Full Text Available We have theoretically analyzed the nuclear quantum effect on the nuclear magnetic shieldings for the intramolecular hydrogen-bonded systems of σ-hydroxy acyl aromatic species using the gauge-including atomic orbital technique combined with our multi-component density functional theory. The effect of H/D quantum nature for geometry and nuclear magnetic shielding changes are analyzed. Our study clearly demonstrated that the geometrical changes of hydrogen-bonds induced by H/D isotope effect (called geometrical isotope effect: GIE is the dominant factor of deuterium isotope effect on 13C chemical shift.

  6. Study on radiation-inducible genes

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sang Yong; Kim, Dong Ho; Joe, Min Ho; Park, Hae Jun; Song, Hyu Npa

    2012-01-15

    Radiation-inducible genes of E. coli, which is a model strain for bacterial study, and Salmonella, which is a typical strain for pathogenic bacteria were compared through omic analysis. Heat shock response genes and prophage genes were induced by radiation in Salmonella, not in E. coli. Among prophage genes tested, STM2628 showed the highest activation by radiation, and approximately 1 kb promoter region was turned out to be necessary for radiation response. To screen an artificial promoter showing activation by 2 Gy, the high-throughput screening method using fluorescent MUG substrate was established. The use of bacteria as anticancer agents has attracted interest. In this study, we tried to develop tumor targeting bacteria in which the radiation-inducible promoter activate a transgene encoding a cytotoxic protein. To do this, a tumor-targeting hfq Salmonella mutant strain was constructed, and we found that its virulence decreased. For outward secretion of anticancer protein produced inside bacteria, the signal peptide of SspH1 was determined and the signal peptide was proven to be able to secrete an anticancer protein. Tumor xenograft mouse model was secured, which can be used for efficiency evaluation of bacterial tumor therapy.

  7. Shielding and activation calculations around the reactor core for the MYRRHA ADS design

    Directory of Open Access Journals (Sweden)

    Ferrari Anna

    2017-01-01

    Full Text Available In the frame of the FP7 European project MAXSIMA, an extensive simulation study has been done to assess the main shielding problems in view of the construction of the MYRRHA accelerator-driven system at SCK·CEN in Mol (Belgium. An innovative method based on the combined use of the two state-of-the-art Monte Carlo codes MCNPX and FLUKA has been used, with the goal to characterize complex, realistic neutron fields around the core barrel, to be used as source terms in detailed analyses of the radiation fields due to the system in operation, and of the coupled residual radiation. The main results of the shielding analysis are presented, as well as the construction of an activation database of all the key structural materials. The results evidenced a powerful way to analyse the shielding and activation problems, with direct and clear implications on the design solutions.

  8. Shielding and activation calculations around the reactor core for the MYRRHA ADS design

    Science.gov (United States)

    Ferrari, Anna; Mueller, Stefan; Konheiser, J.; Castelliti, D.; Sarotto, M.; Stankovskiy, A.

    2017-09-01

    In the frame of the FP7 European project MAXSIMA, an extensive simulation study has been done to assess the main shielding problems in view of the construction of the MYRRHA accelerator-driven system at SCK·CEN in Mol (Belgium). An innovative method based on the combined use of the two state-of-the-art Monte Carlo codes MCNPX and FLUKA has been used, with the goal to characterize complex, realistic neutron fields around the core barrel, to be used as source terms in detailed analyses of the radiation fields due to the system in operation, and of the coupled residual radiation. The main results of the shielding analysis are presented, as well as the construction of an activation database of all the key structural materials. The results evidenced a powerful way to analyse the shielding and activation problems, with direct and clear implications on the design solutions.

  9. Radio-Shield, il primo esperimento italiano sulla Luna. (English Title: Radio-Shield, the first Italian experiment on the Moon)

    Science.gov (United States)

    Barbarossa, M.

    2017-10-01

    Nextly, the first Italian and European experiment will reach the lunar surface. Selected in the international contest Lab2Moon for under-25, the goal of the experiment is to investigate about the possible shielding properties of cyanobacteria against space radiations. If these microorganisms, in addition to providing oxygen and other resources, can also shield from space radiation, they can be used in the development of radiation shields in future interplanetary missions.

  10. Study of heat shielding qualities of brick wall angle with additional insulation located on the outside fences

    Directory of Open Access Journals (Sweden)

    Yurin Oleg

    2017-01-01

    Full Text Available The results of theoretical studies of heat-shielding properties of the angle of external wall a residential building are presented. The brick wall thickness of 510 mm was considered. The studies were performed for the I-st temperature zone of Ukraine. Heat insulation was located on the external side of enclosure. Thermal protection problems of the angle are consideration of the impact of heat-conductive inclusion on adjusted heat transfer resistance of enclosure. Conductive inclusion on the external angle area is its configuration. An additional layer of insulation in the angle area is necessary to use for bringing the level of thermal protection of angle area to the standards. The results of calculations of two-dimensional temperature fields were used for the analysis of thermal protection. Two options for additional insulation were studied. The first option: continuous strip insulation covering the external wall angle. Another one provides division of additional insulation layer into two parts and displacement them from the angle within the design scheme. Studies were performed for different thickness of additional insulation. There was additionally taking into account the value of insulation displacement from the angle for the second option. The optimal location and size of additional insulation were determined. The minimum amount of additional insulation under which the thermal protection requirements are performed was accepted like optimality criterion.

  11. PWR upper/lower internals shield

    Energy Technology Data Exchange (ETDEWEB)

    Homyk, W.A. [Indian Point Station, Buchanan, NY (United States)

    1995-03-01

    During refueling of a nuclear power plant, the reactor upper internals must be removed from the reactor vessel to permit transfer of the fuel. The upper internals are stored in the flooded reactor cavity. Refueling personnel working in containment at a number of nuclear stations typically receive radiation exposure from a portion of the highly contaminated upper intervals package which extends above the normal water level of the refueling pool. This same issue exists with reactor lower internals withdrawn for inservice inspection activities. One solution to this problem is to provide adequate shielding of the unimmersed portion. The use of lead sheets or blankets for shielding of the protruding components would be time consuming and require more effort for installation since the shielding mass would need to be transported to a support structure over the refueling pool. A preferable approach is to use the existing shielding mass of the refueling pool water. A method of shielding was devised which would use a vacuum pump to draw refueling pool water into an inverted canister suspended over the upper internals to provide shielding from the normally exposed components. During the Spring 1993 refueling of Indian Point 2 (IP2), a prototype shield device was demonstrated. This shield consists of a cylindrical tank open at the bottom that is suspended over the refueling pool with I-beams. The lower lip of the tank is two feet below normal pool level. After installation, the air width of the natural shielding provided by the existing pool water. This paper describes the design, development, testing and demonstration of the prototype device.

  12. Study on radiation-responsive epigenomes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Hong; Chung, Byung Yeop; Lee, Seung Sik; Moon, Yu Ran; Lee, Min Hee; Kim, Ji Hong [KAERI, Daejeon (Korea, Republic of)

    2011-01-15

    The purpose of this project is development of world-class headspring techniques of biological science for application of plant genomes/epigenomes through study on radiation- responsive epigenomes and improvement of the national competitiveness in the field of fundamental technology for biological science and industry. Research scope includes 1) Investigation of radiation-responsive epigenomes and elucidation of their relation with phenotypes, 2) Elucidation of interaction and transcription control of epigenomes and epigenetic regulators using ionizing radiation (IR), 3) Investigation of epigenome-mediated traits in plant development, differentiation and antioxidant defense using IR, and 4) Development of application techniques of radiation-responsive epigenomes for eco-monitoring and molecular breeding. Main results are as follow: Setup of conditions for chromatin immunoprecipitation in irradiated plants: investigation of aberrations in DNA methylation after treatment with different IR: elucidation of responses of epigenetic regulators to gamma rays (GR): investigation of aberrations in GR-responsive epigenetic regulators at different developmental stages: elucidation of interactive aberrations of epigenomes and epigenetic regulators after treatment of GR: comparison of functional genomes after treatment of GR or H{sub 2}O{sub 2}: elucidation of relation of epigenomes with GR-induced delay in senescence: elucidation of relation of epigenomes with GR-induced aberrations in pigment metabolism: comparison of antioxidant defense in epigenetic mutants: investigation of senescence-associated changes in epigenomes: investigation of senescence-associated changes in epigenetic regulators: comparison of aberrations in epigenomes at different dose of GR for mutation.

  13. Study on radiation-responsive epigenomes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Hong; Lee, Seung Sik; Bae, Hyung Woo; Kim, Ji Hong; Kim, Ji Eun; Cho, Eun Ju; Lee, Min Hee; Moon, Yu Ran [KAERI, Daejeon (Korea, Republic of)

    2012-01-15

    The purpose of this project is development of world-class headspring techniques of biological science for application of plant genomes/epigenomes through study on radiation- responsive epigenomes and improvement of the national competitiveness in the field of fundamental technology for biological science and industry. Research scope includes 1) Investigation of radiation-responsive epigenomes and elucidation of their relation with phenotypes, 2) Elucidation of interaction and transcription control of epigenomes and epigenetic regulators using IR, 3) Investigation of epigenome-mediated traits in plant development, differentiation and antioxidant defense using IR, and 4) Development of application techniques of radiation-responsive epigenomes for eco-monitoring and molecular breeding. Main results are as follow: practical application of ChIP in GR-treated Arabidopsis using anti-histone antibodies: mapping of DNA methylomes associated with GR-responsive transcriptomes: setup of methylated DNA quantification using HPLC: elucidation of aberrations in epigenetic regulation induced by low-dose GR using gamma phytotron: comparison of gene expression of histone-modifying enzymes after treatment of GR: elucidation of transcriptomes and physiological alterations associated with delayed senescence of drd1-6 mutant: comparison of gene expression of DNA methylation-related enzymes in GR-treated rice callus and Arabidopsis: investigation of germination capacity, low-temperature, salinity and drought stress-resistance in drd1-6 epigenetic mutant: investigation of aberrations in DNA methylation depending on dose rates of gamma radiation

  14. Shadow-Shielding Compensation for Moving Sources Detection

    Science.gov (United States)

    Coulon, Romain; Dumazert, Jonathan

    2017-07-01

    To monitor radioactivity emitted by a vehicle such as a pedestrian, a car, a train, or a truck, radiation portal monitors (RPMs) are commonly employed. It has been noted that these RPM suffer from a shadow-shielding effect when the source is transported by a dense and large vehicle such as a truck or a train. While methods using databases are listed as state of the art, we have developed an approach based on a state model, ensuring a gain in performance and flexibility. This new study presents a technique applied to RPM, efficiently compensating the shadow-shielding effect. A simulation study has been performed to highlight the efficiency and reliability of the method.

  15. CAD-Based Shielding Analysis for ITER Port Diagnostics

    Science.gov (United States)

    Serikov, Arkady; Fischer, Ulrich; Anthoine, David; Bertalot, Luciano; De Bock, Maartin; O'Connor, Richard; Juarez, Rafael; Krasilnikov, Vitaly

    2017-09-01

    Radiation shielding analysis conducted in support of design development of the contemporary diagnostic systems integrated inside the ITER ports is relied on the use of CAD models. This paper presents the CAD-based MCNP Monte Carlo radiation transport and activation analyses for the Diagnostic Upper and Equatorial Port Plugs (UPP #3 and EPP #8, #17). The creation process of the complicated 3D MCNP models of the diagnostics systems was substantially accelerated by application of the CAD-to-MCNP converter programs MCAM and McCad. High performance computing resources of the Helios supercomputer allowed to speed-up the MCNP parallel transport calculations with the MPI/OpenMP interface. The found shielding solutions could be universal, reducing ports R&D costs. The shield block behind the Tritium and Deposit Monitor (TDM) optical box was added to study its influence on Shut-Down Dose Rate (SDDR) in Port Interspace (PI) of EPP#17. Influence of neutron streaming along the Lost Alpha Monitor (LAM) on the neutron energy spectra calculated in the Tangential Neutron Spectrometer (TNS) of EPP#8. For the UPP#3 with Charge eXchange Recombination Spectroscopy (CXRS-core), an excessive neutron streaming along the CXRS shutter, which should be prevented in further design iteration.

  16. Study of chemical and radiation induced carcinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Chmura, A.

    1995-11-01

    The study of chemical and radiation induced carcinogenesis has up to now based many of its results on the detection of genetic aberrations using the fluorescent in situ hybridization (FISH) technique. FISH is time consuming and this tends to hinder its use for looking at large numbers of samples. We are currently developing new technological advances which will increase the speed, clarity and functionality of the FISH technique. These advances include multi-labeled probes, amplification techniques, and separation techniques.

  17. Radiation Chemistry Studies on Chemotherapeutic Agents

    DEFF Research Database (Denmark)

    Gohn, M.; Getoff, N.; Bjergbakke, Erling

    1977-01-01

    Adrenalin has been studied as a model radiation protective agent by means of pulse radiolysis in aqueous solutions. The rate constants for the reactions of adrenalin with e–aq and OH were determined : k(e–aq+ adr—NH+2)= 7.5 × 108 dm3 mol–1 s–1, k(e–aq+ adr—NH)= 2.5 × 108 dm3 mol–1 s–1, and k...

  18. The compliance with and knowledge about radiation protection in operating room personnel: a cross-sectional study with a questionnaire.

    Science.gov (United States)

    Jentzsch, Thorsten; Pietsch, Christiane M; Stigler, Brigitte; Ramseier, Leonhard E; Seifert, Burkhardt; Werner, Clément M L

    2015-09-01

    Radiation protection is becoming more important with an ongoing increase in radiation exposure due to the use of X-rays in minimally invasive procedures in orthopaedic and trauma surgeries. However, sufficient education in medical physics and radiation protection can often be improved. A questionnaire consisting of four questions about personal data and ten questions about radiation protection was distributed to lead consultants, consultants, residents, medical students, and medical technical assistants at two institutions, a level 1 trauma center and a children's hospital. This study consisted of 83 participants. The compliance with radiation protection, i.e., usage of a dosimetry, an apron, and a thyroid shield on a regular basis was only seen in 54 %. Participants from the trauma center wore a dosimeter and thyroid shield significantly more often. The regular use of a thyroid shield differed significantly between job positions. It was observed in 80 % of students, but only 15 % of technical assistants. Only 65 % of all knowledge questions were answered correctly. There was a discrepancy between incorrectly answered knowledge questions (35 %) and those marked as uncertain (20 %). Different job positions did not have an impact on the answers to the questions in most instances. The compliance with and the knowledge about radiation protection seems to be unnecessarily low in trauma physicians and technical assistants. The discrepancy in falsely answered questions and those marked as uncertain may suggest that participants may overestimate their knowledge about radiation protection, which is potentially harmful due to the increased radiation exposure. Therefore, we advocate a quick and valuable training of trauma surgeons and medical staff addressing the important preventive measures, some of which are illustrated in the present study. These consist of wearing dosimetry and protection devices, reduction in X-ray duration, preferably antero-posterior C-arm positioning

  19. Radiation Protection in Medical Physics : Proceedings of the NATO Advanced Study Institute on Radiation Protection in Medical Physics Activities

    CERN Document Server

    Lemoigne, Yves

    2011-01-01

    This book introduces the fundamental aspects of Radiation Protection in Medical Physics and covers three main themes: General Radiation Protection Principles; Radiobiology Principles; Radiation Protection in Hospital Medical Physics. Each of these topics is developed by analysing the underlying physics principles and their implementation, quality and safety aspects, clinical performance and recent advances in the field. Some issues specific to the individual techniques are also treated, e.g. calculation of patient dose as well as that of workers in hospital, optimisation of equipment used, shielding design of radiation facilities, radiation in oncology such as use of brachytherapy in gynecology or interventional procedures. All topics are presented with didactical language and style, making this book an appropriate reference for students and professionals seeking a comprehensive introduction to the field as well as a reliable overview of the most recent developments.

  20. Low Cost, Lightweight, Multifunctional Structural Shielding Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR involves the development of a lightweight innovative material for use as structure and radiation shielding in one. APS has assembled a uniquely qualified...

  1. Studying Radiation Tolerant ICs for LHC

    CERN Multimedia

    Faccio, F; Snoeys, W; Campbell, M; Casas-cubillos, J; Gomes, P

    2002-01-01

    %title\\\\ \\\\In the recent years, intensive work has been carried out on the development of custom ICs for the readout electronics for LHC experiments. As far as radiation hardness is concerned, attention has been focussed on high total dose applications, mainly for the tracker systems. The dose foreseen in this inner region is estimated to be higher than 1~Mrad/year. In the framework of R&D projects (RD-9 and RD-20) and in the ATLAS and CMS experiments, the study of different radiation hard processes has been pursued and good contacts with the manufacturers have been established. The results of these studies have been discussed during the Microelectronics User Group (MUG) rad-hard meetings, and now some HEP groups are working to develop radiation hard ICs for the LHC experiments on some of the available rad-hard processes.\\\\ \\\\In addition, a lot of the standard commercial electronic components and ASICs which are planned to be installed near the LHC machine and in the detectors will receive total doses in ...

  2. Vehicle Shield Optimization and Risk Assessment for Future Human Space Missions

    Science.gov (United States)

    Nounu, Hatem N.; Kim, Myung-Hee; Cucinotta, Francis A.

    2011-01-01

    As the focus of future human space missions shifts to destinations beyond low Earth orbit such as Near Earth Objects (NEO), the moon, or Mars, risks associated with extended stay in hostile radiation environment need to be well understood and assessed. Since future spacecrafts designs and shapes are evolving continuous assessments of shielding and radiation risks are needed. In this study, we use a predictive software capability that calculates risks to humans inside a spacecraft prototype that builds on previous designs. The software uses CAD software Pro/Engineer and Fishbowl tool kit to quantify radiation shielding provided by the spacecraft geometry by calculating the areal density seen at a certain point, dose point, inside the spacecraft. Shielding results are used by NASA-developed software, BRYNTRN, to quantify organ doses received in a human body located in the vehicle in case of solar particle event (SPE) during such prolonged space missions. Organ doses are used to quantify risks on astronauts health and life using NASA Space Cancer Model. The software can also locate shielding weak points-hotspots-on the spacecraft s outer surface. This capability is used to reinforce weak areas in the design. Results of shielding optimization and risk calculation on an exploration vehicle design for missions of 6 months and 30 months are provided in this study. Vehicle capsule is made of aluminum shell that includes main cabin and airlock. The capsule contains 5 sets of racks that surround working and living areas. Water shelter is provided in the main cabin of the vehicle to enhance shielding in case of SPE.

  3. Calculation of Shielding Effectiveness of Materials for Security Devices

    Directory of Open Access Journals (Sweden)

    Kovar Stanislav

    2017-01-01

    Full Text Available Currently, electromagnetic interference constitutes one of the major complications for a function of electronic or electrical devices. Because these devices are constantly exposed to effects of electromagnetic radiation, it is desirable to increase the electromagnetic immunity of device. One of the possibilities is to applicate the suitable shielding materials which can protect the device against the radiated electromagnetic emissions. This paper devotes to finding suitable materials for shielding security devices.

  4. Nuclear Weapons Effects Studies for the 5ESS (Trademark) Switch. Volume 2. EM (Electromagnetic) Shielding Characteristics of Structures.

    Science.gov (United States)

    1986-09-01

    funded AT&T to study the ability of the AT&T SESSTI Switch to withstand the potentially disabling effects of EMP from high - altitude nuclear bursts and...T 5ESSTM Switch to withstand the potentially disabling effects of the electromagnetic pulse (EMP) from high - altitude bursts and the fallout radiation...of a "standard" (unhardened) 5ESS Switch, typical of a rural or suburban installation, upon exposure to a high - altitude EMP ( HEMP ) environmcnt, and

  5. Shield Effect Of Functional Interlining Fabric

    Directory of Open Access Journals (Sweden)

    Šaravanja Bosiljka

    2015-06-01

    Full Text Available Electromagnetic interference (EMI have become very serious in a variety of different electronic equipments, such as personal computers (frequency at several GHz, mobile devices (0.9 – 2.4 GHz and similar. This imposes the need for setting boundaries for EM emission of electric and electronic devices in order to minimize the possibility of interference with radio and wireless communications. Functional textiles can offer protective properties against EM radiation. The aim of this study is to investigate the degree of protection against EM radiation provided by polyamide copper-coated interlining fabric before and after dry cleaning treatment. EM protection efficiency of the interlining functional fabric is explored on both sides at the frequencies of 0.9; 1.8; 2.1 and 2.4 GHz. The results obtained have shown that the interlining fabric has good protective properties against EM radiation, but after dry cleaning, treatment reduction is observed. Scanning electron microscopy micrographs of the interlining surface confirms shield effect decline due to degradation and firing of the copper layers during the process of dry cleaning.

  6. A study of thermal, structural and shielding safety analysis for dry storage of spent nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Shin, S. H. [Kyungpook Nationl Univ., Daegu (Korea, Republic of)

    1997-03-15

    As a replaced method for MRS, the dry storage has been intensively developed by the advanced countries of nuclear power technology. Currently, the domestic technology for the dry storage is also under development. In the present study, the developed technical standards for USNRC and its operation are summarized. Futhermore, the SAR for VECTRA's NUHOMES satisfied with DOE and NRC's requirements is inversely analyzed and combined with both USNRC's regulatory guide and LLNL's SARS. In the safety analysis of a dry storage, the principal design criteria which identifies the structural and mechanical safety criteria is investigated. Based on the design criteria, hypothetical accident analysis as well as off-normal operation analysis are investigated.

  7. The use of nipple shields: A review

    Directory of Open Access Journals (Sweden)

    Selina Chow

    2016-11-01

    Full Text Available A nipple shield is a breastfeeding aid with a nipple-shaped shield that is positioned over the nipple and areola prior to nursing. Nipple shields are usually recommended to mothers with flat nipples or in cases in which there is a failure of the baby to effectively latch onto the breast within the first two days postpartum. The use of nipple shields is a controversial topic in the field of lactation. Its use has been an issue in the clinical literature since some older studies discovered reduced breast milk transfer when using nipple shields, while more recent studies reported successful breastfeeding outcomes. The purpose of this review was to examine the evidence and outcomes with nipple shield use. Methods: A literature search was conducted in Ovid MEDLINE, OLDMEDLINE, EMBASE Classic, EMBASE, Cochrane Central Register of Controlled Trials and CINAHL. The primary endpoint was any breastfeeding outcome following nipple shield use. Secondary endpoints included the reasons for nipple shield use and the average/median length of use. For the analysis, we examined the effect of nipple shield use on physiological responses, premature infants, mothers’ experiences, and health professionals’ experiences. Results: The literature search yielded 261 articles, 14 of which were included in this review. Of these 14 articles, three reported on physiological responses, two reported on premature infants, eight reported on mothers’ experiences, and one reported on health professionals’ experiences. Conclusion: Through examining the use of nipple shields, further insight is provided on the advantages and disadvantages of this practice, thus allowing clinicians and researchers to address improvements on areas that will benefit mothers and infants the most.

  8. Attenuation of a non-parallel beam of gamma radiation by thick shielding-application to the determination of the {sup 235}U enrichment with NaI detectors

    Energy Technology Data Exchange (ETDEWEB)

    Mortreau, Patricia [European Commission, Joint Research Centre, Institute for the Protection and Security of the Citizen, TP 800 Via Fermi, Ispra (Vatican City State, Holy See,) (Italy)]. E-mail: patricia.mortreau@jrc.it; Berndt, Reinhard [European Commission, Joint Research Centre, Institute for the Protection and Security of the Citizen, TP 800 Via Fermi, Ispra (VA) (Italy)

    2005-09-21

    The traditional method used to determine the Uranium enrichment by nondestructive analysis is based on the 'enrichment meter principle' [1]. It involves measuring the intensity of the 186 keV net peak area of {sup 235}U in 'quasi-infinite' samples. A prominent factor, which affects the peak intensity, is the presence of gamma absorbing material (e.g., container wall, detector cover) between the sample and the detector. Its effect is taken into consideration in a commonly called 'wall thickness' correction factor. Often calculated on the basis of approximations, its performance is adequate for small attenuation factors applicable to the case of narrow beams. However these approximations do not lead to precise results when wide non-parallel beams are attenuated through thick container walls. This paper is dedicated to the calculation by numerical integration of the geometrical correction factor (K {sub wtc}) which describes the effective mean path length of the radiation through the absorbing layer. This factor was calculated as a function of various measurement parameters (types and dimensions of the detector, of the collimator and of the shielding) for the most commonly used collimator shapes and detectors. Both coherent scattering (Rayleigh) and incoherent scattering (Compton) are taken into account for the calculation of the radiation interaction within the detector.

  9. Shielding high energy accelerators

    CERN Document Server

    Stevenson, Graham Roger

    2001-01-01

    After introducing the subject of shielding high energy accelerators, point source, line-of-sight models, and in particular the Moyer model. are discussed. Their use in the shielding of proton and electron accelerators is demonstrated and their limitations noted. especially in relation to shielding in the forward direction provided by large, flat walls. The limitations of reducing problems to those using it cylindrical geometry description are stressed. Finally the use of different estimators for predicting dose is discussed. It is suggested that dose calculated from track-length estimators will generally give the most satisfactory estimate. (9 refs).

  10. WASTE HANDLING BUILDING SHIELD WALL ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    D. Padula

    2000-01-13

    The scope of this analysis is to estimate the shielding wall, ceiling or equivalent door thicknesses that will be required in the Waste Handling Building to maintain the radiation doses to personnel within acceptable limits. The shielding thickness calculated is the minimum required to meet administrative limits, and not necessarily what will be recommended for the final design. The preliminary evaluations will identify the areas which have the greatest impact on mechanical and facility design concepts. The objective is to provide the design teams with the necessary information to assure an efficient and effective design.

  11. Use of a genetic algorithm in the search for a near-optimal shielding design

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byeong Soo [Korea Institute of Nuclear Safety, 34 Gwahak-ro, Yuseong-gu, Daejeon 305-338 (Korea, Republic of); Moon, Joo Hyun, E-mail: jhmoon86@dongguk.ac.k [Dongguk University, 707 Seokjang-dong, Gyeongju, Gyeongbuk 780-714 (Korea, Republic of)

    2010-02-15

    An optimization method based on genetic algorithm (GA), which is referred as MACroscopic Near-Optimal Shielding design (MACNOS), is proposed for the search for an optimal radiation shield configuration subject to a given set of constraints. In MACNOS, a GA is used to search for the optimal shielding design and the penalty strategy is employed to deal with the constraints. In order to confirm its capability to search for the optimal shielding design, MACNOS is applied for solving a simple problem with regard to radiation shielding optimization of a hypothetical spaceship reactor. The application shows that, keeping the constraints satisfied, MACNOS is able to seek for the shielding design that minimizes the total weight by changing the thickness and the material of the shield. Therefore, it is expected that MACNOS is potentially useful in the search for the optimal design configuration in the conceptual design phase, where the selection of the shielding material and the estimate of the thickness are necessary.

  12. Study on the Reinforcement Measures and Control Effect of the Surrounding Rock Stability Based on the Shield Tunneling Under Overpass Structure

    Directory of Open Access Journals (Sweden)

    Qian-cheng Fang

    2016-04-01

    Full Text Available To study the stability of surrounding rocks for shield tunneling under overpass structures and the safety of existing bridge structures, a practical example of the method was cited through a shield tunneling project under the overpass structure between K1+110 and K1+700 on Line 2 of Shenyang Subway, China. The sub-area reinforcement was proposed according to surrounding rock deformation characteristics during shield tunnel excavation. The bridge foundation (i.e., the clear spacing to the shield tunnel is less than 2 m was reinforced by steel support, the bridge foundation (the clear spacing is about 2~7m used “jet grouting pile” reinforcement, whereas the bridge foundation (the clear spacing is greater than 7 m did not adopt any reinforcement measures for the moment. For this study, the mean value and material heterogeneity models were established to evaluate the reinforcement effect from several aspects, such as surrounding rock deformation, plastic zone development, and safety factor. The simulation results were consistent with those of field monitoring. After reinforcement, the maximum deformation values of the surrounding rock were reduced by 4.9%, 12.2%, and 48.46%, and the maximum values of surface subsidence were decreased by 5.6%, 72.2%, and 88.64%. By contrast, the overall safety factor was increased by 4.1%, 55.46%, and 55.46%. This study posited that this reinforcement method can be adopted to solve tunnel construction problems in engineering-geological conditions effectively. References for evaluating similar projects are provided.

  13. Evaluation of bismuth shielding effectiveness in reducing breast absorbed dose during thoracic CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, T. C.; Mourao, A. P.; Santana, P. C.; Silva, T. A. [Federal University of Minas Gerais, Program of Nuclear Science and Techniques, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2015-10-15

    Computed Tomography (CT) is an essential method for tracking neoplasia and efficiently diagnosing a wide variety of thoracic diseases. CT is generally considered the most accurate choice for lung examination. Due to the growing use of CT, breast and other superficial and radiosensitive organs are unnecessarily irradiated during radiological procedures, thus requiring the development of strategies appropriate to optimize and, if possible, to reduce the radiation dose. The use of bismuth shielding to reduce radiation dose absorbed by breast during thoracic CT examinations has been the subject of many studies recently published by Brazilian and foreign authors of various fields. The purpose of this paper is both to accurately determine the glandular dose when breast is exposed to radiation and to assess the reduction in absorbed dose during thoracic CT examinations, using a set of Thermoluminescent Dosimeters, an anthropomorphic phantom and bismuth shielding. (Author)

  14. Radiation exposure to the surgeon during percutaneous endoscopic lumbar discectomy: a prospective study.

    Science.gov (United States)

    Ahn, Yong; Kim, Chang-Ho; Lee, June Ho; Lee, Sang-Ho; Kim, Jin-Sung

    2013-04-01

    A prospective study. The purpose of this study was to determine the radiation dose to which the surgeons are exposed during percutaneous endoscopic lumbar discectomy (PELD) and to calculate the allowable number of cases per year. Transforaminal PELD is a minimally invasive technique for soft disc herniation. Minimal invasiveness can be achieved through the use of fluoroscopy and endoscopy. The radiation dose to the surgeon during PELD is unknown. The occupational radiation dose absorbed by 3 spinal surgeons performing 30 consecutive PELDs (33 levels) during a 3-month period was evaluated. Transforaminal PELDs were performed according to the standard technique. The radiation exposure of the neck, chest, arm, and both hands of the surgeons was measured. Occupational exposure guidelines of National Council on Radiation Protection & Measurements were used to calculate the allowable number of procedures per year. The mean operation time was 49.8 minutes, and the mean fluoroscopy time was 2.5 minutes. No significant correlations were found between operation time and fluoroscopy time. The calculated radiation doses per operated level were as follows: neck, 0.0785 mSv; chest, 0.1718 mSv; right upper arm, 0.0461 mSv; left ring finger, 0.7318 mSv; and right ring finger, 0.6694 mSv. The protective effects of a lead collar and lead apron were demonstrated by the reduction of the radiation dose by 96.9% and 94.2%, respectively. Therefore, with regard to whole-body radiation, 5379 operations can be performed per year using a lead apron, whereas only 291 operations can be performed without using a lead apron. Moreover, 1910 operations can be performed within the occupational exposure limit for the eyes (150 mSv), and 683 operations can be performed within the occupational exposure limit for the hands (500 mSv). Without radiation shielding, a surgeon performing 291 PELDs annually would be exposed to the maximum allowable radiation dose. Given the measurable lifetime radiation

  15. Adhesive particle shielding

    Science.gov (United States)

    Klebanoff, Leonard Elliott [Dublin, CA; Rader, Daniel John [Albuquerque, NM; Walton, Christopher [Berkeley, CA; Folta, James [Livermore, CA

    2009-01-06

    An efficient device for capturing fast moving particles has an adhesive particle shield that includes (i) a mounting panel and (ii) a film that is attached to the mounting panel wherein the outer surface of the film has an adhesive coating disposed thereon to capture particles contacting the outer surface. The shield can be employed to maintain a substantially particle free environment such as in photolithographic systems having critical surfaces, such as wafers, masks, and optics and in the tools used to make these components, that are sensitive to particle contamination. The shield can be portable to be positioned in hard-to-reach areas of a photolithography machine. The adhesive particle shield can incorporate cooling means to attract particles via the thermophoresis effect.

  16. Dynamic rotating-shield brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yunlong [Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 (United States); Flynn, Ryan T.; Kim, Yusung [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States); Yang, Wenjun [Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States); Wu, Xiaodong [Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 and Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States)

    2013-12-15

    Purpose: To present dynamic rotating shield brachytherapy (D-RSBT), a novel form of high-dose-rate brachytherapy (HDR-BT) with electronic brachytherapy source, where the radiation shield is capable of changing emission angles during the radiation delivery process.Methods: A D-RSBT system uses two layers of independently rotating tungsten alloy shields, each with a 180° azimuthal emission angle. The D-RSBT planning is separated into two stages: anchor plan optimization and optimal sequencing. In the anchor plan optimization, anchor plans are generated by maximizing the D{sub 90} for the high-risk clinical-tumor-volume (HR-CTV) assuming a fixed azimuthal emission angle of 11.25°. In the optimal sequencing, treatment plans that most closely approximate the anchor plans under the delivery-time constraint will be efficiently computed. Treatment plans for five cervical cancer patients were generated for D-RSBT, single-shield RSBT (S-RSBT), and {sup 192}Ir-based intracavitary brachytherapy with supplementary interstitial brachytherapy (IS + ICBT) assuming five treatment fractions. External beam radiotherapy doses of 45 Gy in 25 fractions of 1.8 Gy each were accounted for. The high-risk clinical target volume (HR-CTV) doses were escalated such that the D{sub 2cc} of the rectum, sigmoid colon, or bladder reached its tolerance equivalent dose in 2 Gy fractions (EQD2 with α/β= 3 Gy) of 75 Gy, 75 Gy, or 90 Gy, respectively.Results: For the patients considered, IS + ICBT had an average total dwell time of 5.7 minutes/fraction (min/fx) assuming a 10 Ci{sup 192}Ir source, and the average HR-CTV D{sub 90} was 78.9 Gy. In order to match the HR-CTV D{sub 90} of IS + ICBT, D-RSBT required an average of 10.1 min/fx more delivery time, and S-RSBT required 6.7 min/fx more. If an additional 20 min/fx of delivery time is allowed beyond that of the IS + ICBT case, D-RSBT and S-RSBT increased the HR-CTV D{sub 90} above IS + ICBT by an average of 16.3 Gy and 9.1 Gy, respectively

  17. Studies on the Neutron Radiation Damage Equivalence

    Directory of Open Access Journals (Sweden)

    ZOU De-hui

    2015-01-01

    Full Text Available To establish a unified standard of the evaluation of different sources of radiation damage, the neutron radiation damage equivalent standard source was determined both at home and abroad, and a lot of equivalence research work was done for making weapons anti neutron radiation performance examination and acceptance basis. The theoretical research progress was combed according to the relationship between the displacement damage function and the radiation source spectra ,and the experimental research progress was combed from the basic experimental methods, the controlling trend of effect parameters and field parameters. The experiment method to reduce the uncertainty was discussed, and present the research directions of radiation damage equivalence.

  18. Study on Earth Radiation Budget mission scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Dlhopolsky, R.; Hollmann, R.; Mueller, J.; Stuhlmann, R. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Atmosphaerenphysik

    1997-12-31

    The goal of this study is to study optimized satellite configurations for observation of the radiation balance of the earth. We present a literature survey of earth radiation budget missions and instruments. We develop a parametric tool to simulate realistic multiple satellite mission scenarios. This tool is a modular computer program which models satellite orbits and scanning operation. We use Meteosat data sampled at three hour intervals as a database to simulate atmospheric scenes. Input variables are satellite equatorial crossing time and instrument characteristics. Regional, zonal and global monthly averages of shortwave and longwave fluxes for an ideal observing system and several realistic satellite scenarios are produced. Comparisons show that the three satellite combinations which have equatorial crossing times at midmorning, noon and midafternoon provide the best shortwave monitoring. Crossing times near sunrise and sunset should be avoided for the shortwave. Longwave diurnal models are necessary over and surfaces and cloudy regions, if there are only two measurements made during daylight hours. We have found in the shortwave inversion comparison that at least 15% of the monthly regional errors can be attributed to the shortwave anisotropic models used. (orig.) 68 refs.

  19. Accelerator shielding experts meet at CERN

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Fifteen years after its first CERN edition, the Shielding Aspects of Accelerator, Targets and Irradiation Facility (SATIF) conference was held again here from 2-4 June. Now at its 10th edition, SATIF10 brought together experts from all over the world to discuss issues related to the shielding techniques. They set out the scene for an improved collaboration and discussed novel shielding solutions.   This was the most attended meeting of the series with more than 65 participants from 34 institutions and 14 countries. “We welcomed experts from many different laboratories around the world. We come from different contexts but we face similar problems. In this year’s session, among other things, we discussed ways for improving the effectiveness of calculations versus real data, as well as experimental solutions to investigate the damage that radiation produces on various materials and the electronics”, says Marco Silari, Chair of the conference and member of the DGS/RP gro...

  20. Progress of the ITER Thermal Shields

    Energy Technology Data Exchange (ETDEWEB)

    Her, Namil, E-mail: namil.her@iter.org [ITER Organisation, Route de Vinon-sur-Verdon – CS 90046, 13067 St Paul-lez-Durance Cedex (France); Hick, Robby; Le Barbier, Robin; Arzoumanian, Terenig; Choi, Chang-Ho; Sborchia, Carlo [ITER Organisation, Route de Vinon-sur-Verdon – CS 90046, 13067 St Paul-lez-Durance Cedex (France); Chung, Wooho; Nam, Kwanwoo; Noh, Chang Hyun; Kang, Dong Kwon; Kang, Gyoung-O. [ITER Korea, National Fusion Research Institute, Daejeon 34133 (Korea, Republic of); Kang, Youngkil; Lim, Kisuk [SFA Engineering Corporation, Hwaseong-si, Gyeonggi-do 10060 (Korea, Republic of)

    2016-11-01

    Highlights: • Design improvement of the ITER Thermal Shields was introduced. • Design of TS manifold and TS instrumentation were summarized. • Produced main material of the TS (SS304LN) was summarized. • Status of the VVTS manufacturing and the inspection requirements were summarized. - Abstract: The role of the ITER Thermal Shields (TS) is to minimize the radiation heat load from the warm components such as vacuum vessel and cryostat to magnet operating at 4.5 K. The final design of TS was completed in 2013 and manufacturing of the vacuum vessel thermal shield (VVTS) is now on-going. This paper describes the development status of the TS in particular the design improvements, the fabrication and the requirements.

  1. Plasma radiation in tokamak disruption simulation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Arkhipov, N.; Bakhtin, V.; Safronov, V.; Toporkov, D.; Vasenin, S.; Zhitlukhin, A. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Wuerz, H. [Forschungszentrum Karlsruhe (Germany)

    1995-12-31

    Plasma impact results in sudden evaporation of divertor plate material and produces a plasma cloud which acts as a protective shield. The incoming energy flux is absorbed in the plasma shield and is converted mainly into radiation. Thus the radiative characteristics of the target plasma determine the dissipation of the incoming energy and the heat load at the target. Radiation of target plasma is studied at the two plasma gun facility 2MK-200 at Troitsk. Space- and time-resolved spectroscopy and time-integrated space-resolved calorimetry are employed as diagnostics. Graphite and tungsten samples are exposed to deuterium plasma streams. It is found that the radiative characteristics depend strongly on the target material. Tungsten plasma arises within 1 {micro}s close to the surface and shows continuum radiation only. Expansion of tungsten plasma is restricted. For a graphite target the plasma shield is a mixture of carbon and deuterium. It expands along the magnetic field lines with a velocity of v = (3--4) 10{sub 6} cm/s. The plasma shield is a two zone plasma with a hot low dense corona and a cold dense layer close to the target. The plasma corona emits intense soft x-ray (SXR) line radiation in the frequency range from 300--380 eV mainly from CV ions. It acts as effective dissipation system and converts volumetrically the incoming energy flux into SXR radiation.

  2. Study on radiation therapy for prostatic cancer

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, T. (Yokohama City Univ. (Japan). Faculty of Medicine)

    1981-10-01

    In an attempt to clarify the effects of radiation therapy for prostatic cancer, the author studied 71 prostatic cancer patients with megavoltage radiation therapy at the Cancer Institute Hospital for the past 17 years between 1964 and 1980. Fifty nine out of 71 cases received combined treatment with hormone. Of 71, 28 patients were examined for remaining foci by transperineal needle biopsy at various times after irradiation. The 5-year actuarial survival rate was 100% for stage A, 92% for stage B, 60.2% for stage C and 25.2% for stage D, respectively. Local control rates by digital rectal examination were 92.3% for stage B and 65.5% for stage C, whereas local atrophy rates were 61.5% for stage B and 31% for stage C cases. The positive rate of biopsy was 75%, negative rate was 20.8% and false negative rate was 4.2% within 1 year. The positive rate decreased to 63.6%, while negative rate increased to 31.8% and false positive rate was 4.6% after 1 year. Some cases, in whom the size of the prostate had decreased, showed good prognosis despite the presence of viable cells in biopsy specimens, therefore the waiting policy seemed indicated by frequent local palpation in future follow up to examine any regrowth in size of the lesion.

  3. Correlation of gamma ray shielding and structural properties of PbO–BaO–P{sub 2}O{sub 5} glass system

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Kulwinder; Singh, K.J., E-mail: kanwarjitsingh@yahoo.com; Anand, Vikas

    2015-04-15

    Highlights: • Transparent glass samples of the system 55PbO{sub x}BaO(45 − x)P{sub 2}O{sub 5} (x = 1 up to 5) have been prepared in the laboratory. • Gamma ray shielding properties improve with the addition of BaO. • Number of non-bridging oxygens decrease with the increase in the content of BaO. • Investigated glass system can be potential candidate as an alternate to conventional radiation shielding ‘concrete’. - Abstract: The presented work has been undertaken to evaluate the applicability of BaO doped PbO-P{sub 2}O{sub 5} glass system as gamma ray shielding material in terms of mass attenuation coefficient and half value layer at photon energies 662, 1173 and1332 keV. A meaningful comparison of their radiation shielding properties has been made in terms of their mass attenuation coefficient and HVL parameters with standard radiation shielding concrete ‘barite’. The density, molar volume, XRD, FTIR, Raman and UV–visible techniques and mechanical properties (by Yamane and Mackenzie's procedure) have been used to study the structural properties of the prepared glass system in order to check the possibility of their commercial utility as alternate to conventional concrete for gamma ray shielding applications.

  4. Additional shielding in front of M2

    CERN Document Server

    Schmidt, B

    2013-01-01

    This note presents studies on possibilities to improve the shielding in front of M2 in order to reduce occupancy of the hottest areas of the Muon System and to mitigate the dead-time problem. Two places for installing additional shielding have been considered: behind HCAL, in place of the PMTs and their bases for the readout, and inside ECAL, in place of the innermost modules of the calorimeter. Studies on the additional shielding inside ECAL have been done for the complementarity of the research rather than for practical purpose due negative effects on the physics. Various studies have been carried out and different configurations of shielding in terms of dimensions and materials have been tested using MC simulations. Moreover the correlation between hits was studied by analysing angles of the tracks passing through M2.

  5. Intraluminal radiation therapy per endoprosthesis: A case study

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, L.A.

    Palliation of cholangeocarcinomas has been achieved by radiation delivered to the bile duct via endoprothesis. This case study supports and extends the works of others by describing the endoscopic techniques involved in the implantation of iridium seeds within a nasobiliary catheter. The case presented demonstrates endoscopic radiation treatment with no systemic radiation effects in a patient whose life extension was 19 months.

  6. Background radiation study of Offa industrial area of Kwara State ...

    African Journals Online (AJOL)

    A study of the external background radiation in Offa industrial area of Kwara State is hereby reported. An in-situ measurement using two Digilert radiation monitors at five different stations were carried out. A mean exposure rate of 0.0132mR/hr, which represents 20% elevation from the standard background radiation, was ...

  7. Influence of the magnetic field orientation on the mixed state properties of high temperature superconductors: an ac shielding study

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, B

    1999-07-01

    This work deals with the influence of the orientation of an applied static magnetic field on the mixed state properties of high temperature superconducting cuprates. The mixed state is characterized by the presence of vortices (quanta of magnetic flux). Their properties have been tested via the dynamic approach of the shielding of an ac magnetic field. In pristine Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} crystals the first order transition of the vortex system from an ordered to a disordered state has been studied. It has been found that in the material the transition is mainly determined by the component of the field perpendicular to the superconducting copper oxide layers. However, the value of this component at the transition diminishes with the increase of the field component parallel to the layers. This is explained by the decrease of the Josephson coupling between 2D vortices in neighbouring planes in the presence of a parallel component. In heavy ion irradiated Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} the subject under investigation has been the pinning of the vortices by the irradiation tracks. These defects push the irreversibility line towards higher fields. In the field range that has become irreversible after irradiation pinning by columnar defects is anisotropic. This anisotropy in pinning indicates that a coupling exists between the 2D vortices that form a vortex line, in contrast to the behaviour in the pristine material in the same field range. HgBa{sub 2}Ca{sub 2}Cu{sub 3}O{sub 8} with columnar defects shows essentially the same behaviour as Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}, the differences being well explained by the lower anisotropy of HgBa{sub 2}Ca{sub 2}Cu{sub 3}O{sub 8} which leads to a more linear character of the vortices. Finally, it has been shown that in pristine Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} the concentration of the vortices in the center of the sample is explained by the surface barrier alone. (author)

  8. Postgraduate studies in radiation biology in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Trott, K.R. [Department of Radiation Biology, Univ. of London (United Kingdom); Lohmann, P.H.M.; Zeeland, A.A. van [Institute of Radiation Genetics and Environmental Mutagenesis, Leiden University Medical Centre, Leiden (Netherlands); Natarajan, A.T. [Institute of Radiation Genetics and Environmental Mutagenesis, Leiden University Medical Centre, Leiden (Netherlands)]|[Interuniversity Research Inst. for Radiopathology and Radiation Protection (Iran, Islamic Republic of)], [Leiden Univ., Leiden (Netherlands); Schibilla, H.; Chadwick, K. [European Commission, ERPET Action, Brussels (Belgium); Kellerer, A.M. [Institute of Radiobiology, Ludwig-Maximilians-University, Munich (Germany); Steinhaeusler, F. [Institute of Physics and Biophysics, Univ. of Salzburg (Austria)

    1998-10-01

    The present system of radiobiological research in universities and research centres is no longer able to train radiobiologists who have a comprehensive understanding of the entire field of radiation biology including both `classical` and molecular radiation biology. However, such experts are needed in view of the role radiation protection plays in our societies. No single institution in Europe could now run a 1-year, full-time course which covers all aspects of the radiobiological basis of radiation protection. Therefore, a cooperative action of several universities from different EU member states has been developed and is described herein. (orig.) With 1 tab.

  9. MATHEMATICAL MODELLING OF THE SHIELDING EFFECTIVENESS FOR PES/STAINLESS STEEL FABRICS

    Directory of Open Access Journals (Sweden)

    RADULESCU Ion Razvan

    2017-05-01

    Full Text Available Textile screens for electromagnetic radiation represent a modern solution, due to their flexibility, lightweight and good mechanical resistance. Electromagnetic shielding is a must in various applications, while strict regulations are set for electromagnetic compatibility. Conductive fabrics are widely used for electronic equipment covers, RF suits or EMI protection tents. This paper aims to investigate the shielding effectiveness of conductive woven fabrics with stainless steel yarns at different weft distances [2,3,4,5 mm]. These conductive fabrics were investigated for their physical-mechanical properties (mass per surface unit, density on warp and weft direction and thickness, within the INCDTP accredited laboratories. The conductive fabrics as well as combinations thereof where tested for their shielding effectiveness accordingly to the standard ASTM ES 07, within the EMC laboratories of ICPE-CA. A signal generator, an amplifier, a TEM Cell and a spectrum analyser were used were used for this purpose. Graphs in logarithmic scale were issued for the shielding effectiveness analysis. Moreover, an experimental factorial plan was conceived for obtaining a mathematical model for the studied fabrics in relation to the weft distance between the conductive yarns. The coefficients of the mathematical model were obtained through the least squares regression method in Excel, while the response curve was designed in Matlab. The response curve enables the computation of intermediate values of the shielding effectiveness in relation to the distance between conductive yarns.

  10. Experimental investigation of clay fly ash bricks for gamma-ray shielding

    Energy Technology Data Exchange (ETDEWEB)

    Mann Harjinder Singh; Mudahar, Gumel Singh [Dept. of Physics, Punjabi University, Patiala (India); Brar, Gurdarshan Singh [Dept. of Higher Education, Additional Project Director, Chandigarh (India); Mann, Kulwinder Singh [Dept. of Applied Sciences, I.K. Gujral Punjab Technical University, Jalandhar (India)

    2016-10-15

    This study aims to determine the effect of fly ash with a high replacing ratio of clay on the radiation shielding properties of bricks. Some interaction parameters (mass attenuation coefficients, half value layer, effective atomic number, effective electron density, and absorption efficiency) of clay fly ash bricks were measured with a NaI(Tl) detector at 661.6 keV, 1,173.2 keV, and 1,332.5 keV. For the investigation of their shielding behavior, fly ash bricks were molded using an admixture to clay. A narrow beam transmission geometry condition was used for the measurements. The measured values of these parameters were found in good agreement with the theoretical calculations. The elemental compositions of the clay fly ash bricks were analyzed by using an energy dispersive X-ray fluorescence spectrometer. At selected energies the values of the effective atomic numbers and effective electron densities showed a very modest variation with the composition of the fly ash. This seems to be due to the similarity of their elemental compositions. The obtained results were also compared with concrete, in order to study the effect of fly ash content on the radiation shielding properties of clay fly ash bricks. The clay fly ash bricks showed good shielding properties for moderate energy gamma rays. Therefore, these bricks are feasible and eco-friendly compared with traditional clay bricks used for construction.

  11. Alternatives evaluation and decommissioning study on shielded transfer tanks at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    DeVore, J.R.; Hinton, R.R.

    1994-08-01

    The shielded transfer tanks (STTs) are five obsolete cylindrical shipping casks which were used to transport high specific activity radioactive solutions by rail during the 1960s and early 1970s. The STTs are currently stored at the Oak Ridge National Laboratory under a shed roof. This report is an evaluation to determine the preferred alternative for the final disposition of the five STTs. The decommissioning alternatives assessed include: (1) the no action alternative to leave the STTs in their present location with continued surveillance and maintenance; (2) solidification of contents within the tanks and holding the STTs in long term retrievable storage; (3) sale of one or more of the used STTs to private industry for use at their treatment facility with the remaining STTs processed as in Alternative 4; and (4) removal of tank contents for de-watering/retrievable storage, limited decontamination to meet acceptance criteria, smelting the STTs to recycle the metal through the DOE contaminated scrap metal program, and returning the shielding lead to the ORNL lead recovery program because the smelting contractor cannot reprocess the lead. To completely evaluate the alternatives for the disposition of the STTs, the contents of the tanks must be characterized. Shielding and handling requirements, risk considerations, and waste acceptance criteria all require that the radioactive inventory and free liquids residual in the STTs be known. Because characterization of the STT contents in the field was not input into a computer model to predict the probable inventory and amount of free liquid. The four alternatives considered were subjected to a numerical scoring procedure. Alternative 4, smelting the STTs to recycle the metal after removal/de-watering of the tank contents, had the highest score and is, therefore, recommended as the preferred alternative. However, if a buyer for one or more STT could be found, it is recommended that Alternative 3 be reconsidered.

  12. Studies on application of radiation and radioisotope. Studies on radiation processing

    Energy Technology Data Exchange (ETDEWEB)

    Nho, Young Chang; Jin, J. H.; Kim, K. Y.; Lee, Y. K.; Lee, M. Z.; Jung, S. H.; Park, S. C.; Na, B. Z.; Kim, J. H.; Park, J. S.; Kwon, O. H.

    1997-09-01

    An attempt was made to synthesize adsorbent by radiation grafting of monomers onto polypropylene fabric, and then introducing functional groups such as cation-exchange and anion-exchange. The capacities of the synthesized adsorbents having the cationic and anionic exchange groups were evaluated by determining the degree to adsorb the basic and acidic gas, respectively. Software for RTD analysis was made to analyze data from radiotracer experiments. A pilot plant for practicing tracer experiments was designed and constructed, and experimental procedures for several tracer techniques were established. Radiation source holder, detector collimator, driver unit and software to control them were designed and constructed for column scanning technique. Basic studies for sea sand movement were performed and some tracer experiments were executed to support local industry as well as to gain field experiences. Cellulosic agricultural waste was observed by SEM for structural changes and analysed by thermal gravity analysis and water holding capacity test for the physical characteristics as a function of radiation dose. The number and kind of microorganisms in cellulosic agricultural waste were determined and sterilized by the reasonable radiation dose. The optimal fermentable microorganism is evaluated by the fermentation experiments of various useful strains. (author). 20 refs., 4 tabs., 39 figs.

  13. Detailed mechanical design of the LIPAc beam dump radiological shielding

    Energy Technology Data Exchange (ETDEWEB)

    Nomen, Oriol, E-mail: onomen@irec.cat [IREC, Barcelona, Catalonia (Spain); CDEI-UPC, Barcelona, Catalonia (Spain); Martínez, José I.; Arranz, Fernando; Iglesias, Daniel; Barrera, Germán; Brañas, Beatriz [CIEMAT, Madrid (Spain); Ogando, Francisco [UNED, Madrid (Spain); Molla, Joaquín [CIEMAT, Madrid (Spain); Sanmartí, Manel [IREC, Barcelona, Catalonia (Spain)

    2013-10-15

    Highlights: ► Mechanical design of the IFMIF LIPAc beam dump shielding has been performed. ► Lead shutter design performed to shield radiation from beam dump when LIPAc is off. ► External loads, working and dismantling conditions, included as design constraints. -- Abstract: The LIPAc is a 9 MeV, D{sup +} linear prototype accelerator for the validation of the IFMIF accelerator design. The high intensity, 125 mA CW beam is stopped in a copper cone involving a high production of neutrons and gamma radiation and activation of its surface. The beam stopper is surrounded by a shielding to attenuate the resulting radiation so that dose rate values comply with the limits at the different zones of the installation. The shielding includes for that purpose polyethylene rings, water tanks and gray cast iron rings. A lead shutter has also been designed to shield the gamma radiation that comes through the beam tube when the linear accelerator is not in operation, in order to allow access inside the building for maintenance tasks. The present work summarizes the detailed mechanical design of the beam dump shielding and the lead shutter taking into account the design constraints, such as working conditions and other external loads, as well as including provisions for dismantling.

  14. In-beam background suppression shield

    DEFF Research Database (Denmark)

    Santoro, V.; Cai, Xiao Xiao; DiJulio, D. D.

    2015-01-01

    , which do not use a bender to help mitigate the fast neutron background, are the most challenging. For these beam lines we propose the innovative shielding of placing blocks of material directly into the guide system, which allow a minimum attenuation of the cold and thermal fluxes relative...... to the background suppression. This shielding configuration has been worked into a beam line model using Geant4. We study particularly the advantages of single crystal sapphire and silicon blocks....

  15. Study on radiation transfer in human skin for cosmetics

    Science.gov (United States)

    Yamada, Jun; Kawamura, Ayumu; Miura, Yoshimasa; Takata, Sadaki; Ogawa, Katsuki

    2005-06-01

    In order to design cosmetics producing the optical properties that are required for a beautiful skin, the radiation transfer in the skin has been numerically investigated by the Monte Carlo method and the effects of skin texture and cosmetics on the radiation transfer have been empirically investigated using an artificial skin. The numerical analysis showed that the total internal reflection suppresses large portion of radiation going out through the skin surface Additionally, the experimental study revealed that skin texture and cosmetics not only diffusely reflect the incoming radiation, but also lead the internally reflected radiation to the outside of the skin.

  16. Study and installation of concrete shielding in the civil engineering of nuclear construction (1960); Etude et mise en place des betons de protection dans le genie civil des ouvrages nucleaires (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Dubois, F. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The object of this report is to give technical information about high density concretes which have become very important for radiation biological shielding. The most generally used heavy aggregates (barytes, ilmenite, ferrophosphorus, limonite, magnetite and iron punching) to make these concretes are investigated from the point of view prospecting and physical and chemical characteristics. At first, a general survey of shielding concretes is made involving the study of components, mixing and placing methods, then, a detailed investigation of some high density concretes: barytes concrete, with incorporation of iron punching or iron shot, ferrophosphorus concrete, ilmenite concrete and magnetite concrete, more particularly with regard to grading and mix proportions and testing process. To put this survey in concrete form, two practical designs are described such as they have been carried out at the Saclay Nuclear Station. Specifications are given for diverse concretes and for making the proton-synchrotron 'Saturne' shielding blocks. (author) [French] Ce rapport a pour objet de donner des precisions techniques au sujet des betons a haute densite qui ont pris une grande importance pour la protection biologique contre les rayonnements. Les agregats lourds les plus couramment utilises (barytine, ilmenite, ferrophosphore, limonite, magnetite et riblons) pour la fabrication de ces betons, sont examines du point de vue prospection et caracteristiques physiques et chimiques. On procede d'abord a une etude generale des betons de protection comprenant l'etude des constituants, de la confection et de la mise en place, ensuite, a un examen detaille de quelques betons a haute densite: betons a base de barytine, avec incorporation de riblons ou de grenaille de fonte, betons au ferrophosphore, a base d'ilmenite ou de magnetite, notamment en ce qui concerne la granulometrie, la composition, le dosage et les processus d'essais. Pour concretiser ces

  17. Nuclear characteristics of epoxy resin as a space environment neutron shielding

    Energy Technology Data Exchange (ETDEWEB)

    Adeli, Ruhollah [Nuclear Science and Technology Research Institute, Yazd (Iran, Islamic Republic of). Central Iran Research Complex; Shirmardi, Seyed Pezhman [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Radiation Application Research School; Mazinani, Saideh [Amirkabir Nanotechnology Research Institute, Tehran (Iran, Islamic Republic of); Ahmadi, Seyed Javad [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Nuclear Fuel Cycle Research School

    2017-03-15

    In recent years many investigations have been done for choosing applicable light neutron shielding in space environmental applications. In this study, we have considered the neutron radiation-protective characteristics of neat epoxy resin, a thermoplastic polymer material and have compared it with various candidate materials in neutron radiation protection such as Al 6061 alloy and Polyethylene. The aim of this investigation is the effect of type of moderator for fast neutron, notwithstanding neutron absorbers fillers. The nuclear interactions and the effective dose at shields have been studied with the Monte Carlo N-Particle transport code (MCNP), using variance reductions to reduce the relative error. Among the candidates, polymer matrix showed a better performance in attenuating fast neutrons and caused a lower neutron and secondary photon effective dose.

  18. II. Biological studies of radiation effects

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, J.H.

    1948-05-24

    With the completion of the 184 inch cyclotron in Berkeley and the successful construction of a deflector system, it was possible to bring the 190 Mev deuteron and the 380 Mev alpha beams out into the air and to begin a study of the effects of high-energy deuteron beams by direct irradiation of biological specimens. The direct biological use of deuteron beams was attempted earlier in Berkeley by Marshak, MacLeish, and Walker in 1940. These and other investigators have been aware for some time of the potential usefulness of high energy particle beams for radio-biological studies and their suitability for biological investigations. R.R. Wilson advanced the idea of using fast proton beams to deliver radiation and intervening tissues. R.E. Zirkle pointed out that such particle beams may be focused or screened until a cross-section of the beam is small enough to study effects of irradiation under the microscope on single cells or on parts of single cells. This article gives an overview of the radiological use of high energy deuteron beams, including the following topics: potential uses of high energy particle beams; experiments on the physical properties of the beam; lethal effect of the deuteron beam on mice.

  19. Analytical study of modern paint layers on metal knight shields: the use and effect of titanium white.

    Science.gov (United States)

    Lauridsen, Clara Bratt; Sanyova, Jana; Simonsen, Kim Pilkjær

    2014-04-24

    Painted metal knight shields of the Order of the Elephant produced during the last part of the 20th century are characterized by a striking variety in their conservation state. Three different coat systems were identified and investigated by Fourier transform infrared microscopy (μ-FTIR), micro-Raman spectroscopy (MRS), scanning electron microscopy-Energy dispersive X-ray spectroscopy (SEM-EDX) and Thermally assisted hydrolysis and methylation-gas chromatography-mass Spectrometry (THM-GC-MS). Chalking of the white paint layer on the first group of knight shields displayed in the window niches was found to be related to the use of titanium white of the anatase type. A pristine condition of the second group could be attributed to priming of the lead rich metal support with a zinc potassium chromate based primer and the use of mainly stable white pigments in the top coat. Severe delamination of the paint layer of the third group was caused by the formation of lead corrosion products between the paint layer and the metal support. The results are discussed in relation to the climatic conditions as well as the historical context of contemporary paint production and availability in Denmark. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Effects of shielding the radiosensitive superficial organs of ORNL pediatric phantoms on dose reduction in computed tomography

    Directory of Open Access Journals (Sweden)

    Parisa Akhlaghi

    2014-01-01

    Full Text Available In computed tomography (CT, some superficial organs which have increased sensitivity to radiation, receive doses that are significant enough to be matter of concern. Therefore, in this study, the effects of using shields on the amount of dose reduction and image quality was investigated for pediatric imaging. Absorbed doses of breasts, eyes, thyroid and testes of a series of pediatric phantoms without and with different thickness of bismuth and lead were calculated by Monte Carlo simulation. Appropriate thicknesses of shields were chosen based on their weights, X-ray spectrum, and the amount of dose reduction. In addition, the effect of lead shield on image quality of a simple phantom was assessed quantitatively using region of interest (ROI measurements. Considering the maximum reduction in absorbed doses and X-ray spectrum, using a lead shield with a maximum thickness of 0.4 mm would be appropriate for testes and thyroid and two other organs (which are exposed directly should be protected with thinner shields. Moreover, the image quality assessment showed that lead was associated with significant increases in both noise and CT attenuation values, especially in the anterior of the phantom. Overall, the results suggested that shielding is a useful optimization tool in CT.

  1. Studies on the strategies of minimizing radiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Hee Yong; Sohn, Young Sook

    1998-04-01

    We studied on the strategies of minimizing radiation damage in animal system. To this end we studied following areas of research (1) mechanisms involved in bone marrow damage after total body irradiation, (2) extraction of components that are useful in protecting hematopoietic system from radiation damage, (3) cell therapy approach in restoring the damaged tissue, (4) development of radioprotective chemical reagent, and (5) epidemiological study on the population that had been exposed to radiation.

  2. Molecular photoemission studies using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Truesdale, C.M.

    1983-04-01

    The angular distributions of photoelectrons and Auger electrons were measured by electron spectroscopy using synchrotron radiation. The experimental results are compared with theoretical calculations to interpret the electronic behavior of photoionization for molecular systems.

  3. Radiation effect studies on anticancer drugs, cyclophosphamide and doxorubicin for radiation sterilization

    Science.gov (United States)

    Varshney, L.; Dodke, P. B.

    2004-12-01

    Two anticancer drugs, cyclophosphamide (CPH) and doxorubicin hydrochloride (DOXO), in powder form were exposed to a range of doses of 60Co gamma and electron beam radiation to study the effects of ionizing radiation. Pharmacopoeia tests, discolouration, degradation products, effect of irradiation temperature and dose rate were investigated. CPH undergoes less than 2% degradation at 30 kGy. Chromatographic studies revealed formation of several trace level degradation products, discolouration and free radicals in the irradiated CPH. N, N-bis (2-chloroethyl) group in the molecule is particularly sensitive to radiation degradation. Irradiation to 5 kGy at low temperature (77 K) did not result in significant changes. DOXO was observed to be quite radiation resistant and did not undergo significant changes in its physico-chemical properties and degradation product profile. It can be radiation sterilized at normal sterilization dose of 25 kGy.

  4. Studies on application of radiation and radioisotopes -Studies on radiation processing-

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Joon Hah; Yoon, Byung Mok; Kim, Kee Yub; Noh, Yung Chang; Lee, Yung Keun; Lee, Myun Joo; Park, Soon Chul; Nah, Bong Joo; Kim, Jae Hoh; Byun, Hyung Jik [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-07-01

    Using {gamma}-ray and electron beam, acrylic acid was grafted on polyethylene film in the presence of additives such as acid and metallic salts. The effect of metal salts and acid on the graft yield was evaluated. The graft mechanism and the physical property of grafted films were also examined. Radiation sensitivities of pathogenic microbes in waste sludges were determined to get theoretical radiation dose for disinfection. Experimental radiation dose for disinfection was investigated using real activated and digestive sludge. Feasibility of the method was studied from the experimental results. Virgin, waste and regenerated activated carbon were irradiated with electron beam with and without steam. Micropore distribution, BET surface area and sorption capacity were measured before and after irradiation. The residence time distributions of flue gas in the irradiation chamber of an electron beam flue gas treatment plant to study the effect of baffles were measured. The flow rates of gaseous material in the propylene production plant were measured to identify the origin of it`s malfunction. The equipment for column scanning were designed for production. 45 figs, 10 tabs, 30 refs. (Author).

  5. Electrostatic shielding of transformers

    Energy Technology Data Exchange (ETDEWEB)

    De Leon, Francisco

    2017-11-28

    Toroidal transformers are currently used only in low-voltage applications. There is no published experience for toroidal transformer design at distribution-level voltages. Toroidal transformers are provided with electrostatic shielding to make possible high voltage applications and withstand the impulse test.

  6. Shield For Flexible Pipe

    Science.gov (United States)

    Ponton, Michael K.; Williford, Clifford B.; Lagen, Nicholas T.

    1995-01-01

    Cylindrical shield designed to fit around flexible pipe to protect nearby workers from injury and equipment from damage if pipe ruptures. Designed as pressure-relief device. Absorbs impact of debris ejected radially from broken flexible pipe. Also redirects flow of pressurized fluid escaping from broken pipe onto flow path allowing for relief of pressure while minimizing potential for harm.

  7. Shielding for neutrons produced by medical linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Rebello, Wilson F.; Silva, Ademir X. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Nuclear]. E-mail: rebello@ime.eb.br; ademir@con.ufrj.br

    2007-07-01

    The shielding system called Multileaf Shielding (MLS) was designed in Brazil to be used for protection patients, who undergo radiotherapy treatment, against undesired neutrons produced in the medical linear accelerator heads. During the conceiving of the MLS it was necessary to evaluate its efficiency. For that purpose, several simulations using the Monte Carlo N-particle radiation transport code, MCNP5, were made, in order to evaluate the response of the new shielding system. The results showed a significant neutron dose reduction after the inclusion of the MLS. This work aims to presenting these simulation results. (author)

  8. Energy deposition study of low-energy cosmic radiation at sea level

    Science.gov (United States)

    Wijesinghe, Pushpa

    In this dissertation work, a computer simulation model based on the Geant4 simulation package has been designed and developed to study the energy deposition and track structures of cosmic muons and their secondary electrons in tissue-like materials. The particle interactions in a cubic water volume were first simulated. To analyze the energy deposition and tracks in small structures, with the intention of studying the energy localization in nanometric structures such as DNA, the chamber was sliced in three dimentions. Validation studies have been performed by comparing the results with experimental, theoretical, and other simulation results to test the accuracy of the simulation model. A human body phantom in sea-level muon environment was modeled to measure the yearly dose to a human from cosmic muons. The yearly dose in this phantom is about 22 millirems. This is close to the accepted value for the yearly dose from cosmic radiation at sea level. Shielding cosmic muons with a concrete slab from 0 to 2 meters increased the dose received by the body. This dissertation presents an extensive study on the interactions of secondary electrons created by muons in water. Index words. Radiation Dosimetry Simulation, Track Structures, Sea-Level muon Flux, Energy Deposition

  9. Radiation protection during hybrid procedures: innovation creates new challenges.

    Science.gov (United States)

    Sawdy, Jaclynn M; Gocha, Mark D; Olshove, Vincent; Chisolm, Joanne L; Hill, Sharon L; Phillips, Alistair; Galantowicz, Mark; Cheatham, John P; Holzer, Ralf J

    2009-09-01

    The cooperation between interventional cardiologists and cardiothoracic surgeons has expanded the spectrum of treatment modalities for patients with congenital heart disease. These hybrid techniques have created new challenges, one of which being the provision of adequate but practical radiation protection. This study evaluates the use of a lightweight radiation protection drape (RADPAD) that may be suitable for shielding during hybrid procedures. To simulate a pediatric patient, an 8.7 liter water-filled tub was placed on an X-ray table and exposed to 10-second cine acquisition runs. Radiation exposure was measured at twelve specified locations around the table using a model with three different levels of radiation protection: no shielding, shielding using a traditional 0.35 mm lead-equivalent apron, and shielding using the 0.25 mm lead-equivalent RADPAD. The traditional lead apron and the RADPAD significantly reduced the amount of radiation dose when compared with no shielding. The standard lead apron provided slightly greater radiation protection than the RADPAD (0.000064 radiation absorbed dose [rad] vs. 0.000091 rad; p = 0.012). The measured rad was significantly higher on the right side of the table, and the measured radiation dose decreased significantly with increasing distance from the table. The RADPAD has been shown to function as an efficient shielding device, even though it does not quite match the protection that can be expected from a standard lead apron. It complies with regulatory radiation protection requirements and its lightweight and sterile use make it particularly useful during hybrid procedures in the operating room.

  10. Usability evaluation through gonad shielding production of pediatric patients by gender and age rating

    Energy Technology Data Exchange (ETDEWEB)

    Chui, Sung Hyun; Park, Jung Eun [Dept. of Radiology, Kyung Hee University Hospital at Gangdong, Seoul (Korea, Republic of); Chun, Woon Kwan; Ju, Yong Jin; Yang, Nam Hee [Dept. of Nuclear Engineering, Chosun University, Gwangju (Korea, Republic of); Dong, Kyung Rae [Dept. of Radiological Technology, Gwangju Health University, Gwangju (Korea, Republic of)

    2015-05-15

    The gonad shielding is used to minimize the impact of the exposure to gonads when Abdomen, Plevis and Hip X-ray inspections are conducted on radiation impressionable pediatric patients. By the way, the gonad is palpable difficult and impossible to check visually because it's a sensitive area, so tests are conducted with the approximate location of shielding, thereby appearing problems of not shielding gonads accurately. Accordingly, this study produced shields by age and gender of pediatric patients and studied the method of positioning shields with ASIS as a reference point without palpable sensitive areas, and tried to evaluate its usability. The study surveyed 30 pediatric patients by gender and age, who came and got inspected in Department of Radiology, our hospital from February 2012 to January 2014 and obtained the value of tolerance by measuring the average size of the pelvis using the distance measurement function of Infinitt Piview with the images stored in the PACS and producing shields by age and gender of pediatric patients and specifying the areas at random for the comparative analysis of pre- and post-using. It calculated the technology statistics (mean±SD) with the value of tolerance measured the length using SPSS 12.0 statistical program. As for boys, differences in the tolerance range of pre- and post-using shields were 2.69 mm in case of 1 year old, 2.58 mm in 2 years, 2.37 mm in 3 years, 2.815 mm in 4-5 years, 2.043 mm in 7-10 years, and as for girls,1.92 mm in 1-2 years, 1.75 mm in 3-4 years, 2.52 mm in 5-6 years and 1.93 mm in 7-10. After analyzing the pre- and post-using shields for all of boys and girls, there were statistically significant differences (P<0.050). It is considered that we can minimize the exposure to gonads and get a better video for diagnosis in testing high biological impressionable pediatric, if we use shields correctly with ASIS as a reference point considering its shape and size by age and gender in Abdomen, Plevis

  11. Development of the safety control framework for shield tunneling in close proximity to the operational subway tunnels: case studies in mainland China.

    Science.gov (United States)

    Li, Xinggao; Yuan, Dajun

    2016-01-01

    China's largest cities like Beijing and Shanghai have seen a sharp increase in subway network development as a result of the rapid urbanization in the last decade. The cities are still expanding their subway networks now, and many shield tunnels are being or will be constructed in close proximity to the existing operational subway tunnels. The execution plans for the new nearby shield tunnel construction calls for the development of a safety control framework-a set of control standards and best practices to help organizations manage the risks involved. Typical case studies and relevant key technical parameters are presented with a view to presenting the resulting safety control framework. The framework, created through collaboration among the relevant parties, addresses and manages the risks in a systematic way based on actual conditions of each tunnel crossing construction. The framework consists of six parts: (1) inspecting the operational subway tunnels; (2) deciding allowed movements of the existing tunnels and tracks; (3) simulating effects of the shield tunneling on the existing tunnels; (4) doing preparation work; (5) monitoring design and information management; and (6) measures and activation mechanism of the countermeasures. The six components are explained and demonstrated in detail. In the end, discussions made involve construction and post-construction settlement of the operational tunnel, application of the remedial grouting to rectify excessive settlements of the operational tunnel, and use of the innovative tool of the optical fiber measurement for tunnel movement monitoring. It is concluded that the construction movement of the tunnel can be controlled within 15 mm when the shield machine is tunnel buried in the very soft ground is much greater than its construction settlement, and last several years until reaching a final stable state. Two cases are outlined to demonstrate the feasibility of using the remedial grouting to reduce the long

  12. Studies of photon spectra from a thallium-204 foil source as an aid to dosimetry and shielding

    CERN Document Server

    Francis, T M

    1976-01-01

    Beta ray foil sources incorporating nuclides such as thallium-204, promethium-147 and strontium-90 plus yttrium-90 ar increasingly used in industrial devices such as thickness gauges. These sources are so constructed that they give rise to complex photon spectra containing low energy Bremsstrahlung and X-rays characteristic of the constructional materials. The energy response of practical monitoring instruments is such that they are likely to underestimate the dose due to such spectra unless they are calibrated using appropriate spectra. This report describes a series of measurements carried out on a commercially available thallium-204 foil source and five commonly used shielding materials. The measurements made with a NaI(T1) spectrometer have been corrected for instrumental distortions to obtain the photon spectra in air. These spectra are presented and have been used to compute dose in air with the help of published data on mass energy-absorption coefficients. Also included in the report are data derived f...

  13. SHIELD 1.0: development of a shielding calculator program in diagnostic radiology; SHIELD 1.0: desenvolvimento de um programa de calculo de blindagem em radiodiagnostico

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Romulo R.; Real, Jessica V.; Luz, Renata M. da [Hospital Sao Lucas (PUCRS), Porto Alegre, RS (Brazil); Friedrich, Barbara Q.; Silva, Ana Maria Marques da, E-mail: ana.marques@pucrs.br [Pontificia Universidade Catolica do Rio Grande do Sul (PUCRS), Porto Alegre, RS (Brazil)

    2013-08-15

    In shielding calculation of radiological facilities, several parameters are required, such as occupancy, use factor, number of patients, source-barrier distance, area type (controlled and uncontrolled), radiation (primary or secondary) and material used in the barrier. The shielding design optimization requires a review of several options about the physical facility design and, mainly, the achievement of the best cost-benefit relationship for the shielding material. To facilitate the development of this kind of design, a program to calculate the shielding in diagnostic radiology was implemented, based on data and limits established by National Council on Radiation Protection and Measurements (NCRP) 147 and SVS-MS 453/98. The program was developed in C⌗ language, and presents a graphical interface for user data input and reporting capabilities. The module initially implemented, called SHIELD 1.0, refers to calculating barriers for conventional X-ray rooms. The program validation was performed by the comparison with the results of examples of shielding calculations presented in NCRP 147.

  14. ORDNANCE CORPS VIEWS ELECTROMAGNETIC RADIATION HAZARDS TO WEAPONS SYSTEMS,

    Science.gov (United States)

    EXPLOSIVES INITIATORS, * ELECTROMAGNETIC RADIATION ), HAZARDS, ELECTROMAGNETIC SHIELDING, RADIOFREQUENCY POWER, ANTENNAS, ATTENUATORS, IMPEDANCE MATCHING, SENSITIVITY, WEAPON SYSTEMS, MODULATION, CIRCUITS, BROADBAND

  15. Shielding design of an underground experimental area at point 5 of the CERN Super Proton Synchrotron (SPS).

    Science.gov (United States)

    Mueller, Mario J; Stevenson, Graham R

    2005-01-01

    Increasing projected values of the circulating beam intensity in the Super Proton Synchrotron (SPS) and decreasing limits to radiation exposure, taken with the increasing non-acceptance of unjustified and unoptimised radiation exposures, have led to the need to re-assess the shielding between the ECX and ECA5 underground experimental areas of the SPS. Twenty years ago, these experimental areas at SPS-Point 5 housed the UA1 experiment, where Carlo Rubbia and his team verified the existence of W and Z bosons. The study reported here describes such a re-assessment based on simulations using the multi-purpose FLUKA radiation transport code. This study concludes that while the main shield which is made of concrete blocks and is 4.8 m thick satisfactorily meets the current design limits even at the highest intensities presently planned for the SPS, dose rates calculated for liaison areas on both sides of the main shield significantly exceed the design limits. Possible ways of improving the shielding situation are discussed.

  16. Investigation of gamma-ray shielding effectiveness of natural marble used for external wall cladding of buildings in Riyadh, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Ibrahim F. Al-Hamarneh

    Full Text Available Gamma-ray shielding effectiveness of different types of natural marble tiles commonly used for cladding the exterior walls of residential and non-residential buildings in Riyadh, Saudi Arabia has been investigated in the energy range 59.5–1332.5 keV. To this end, linear attenuation coefficients (μℓ have been obtained by applying narrow-beam technique. Mass attenuation coefficient (μm, transmission factor (TF and half-value layer (HVL have been employed to study the shielding performance of marbles and also compared with those of calcite. The experimental findings revealed that HVL parameter correctly determined the shielding effectiveness of the dissimilar types of marble. Compared with other marbles, Carrara marble (Italy showed preferable shielding effectiveness. Moreover, a formula, μm = aE−b, was proposed to evaluate and compare the shielding properties of the marble tiles over a broad energy range. In this formula, a and b were determined empirically. In conclusion, natural marble proves to be more reliable in reducing gamma radiation when used for external building cladding than ordinary concrete, and it could be a good alternative to lead shield against high gamma energy because it is 24% heavier than lead. Keywords: Gamma-ray shielding effectiveness, Attenuation coefficients, HVL, Transmission factor, Natural marble

  17. A study of Monte Carlo radiative transfer through fractal clouds

    Energy Technology Data Exchange (ETDEWEB)

    Gautier, C.; Lavallec, D.; O`Hirok, W.; Ricchiazzi, P. [Univ. of California, Santa Barbara, CA (United States)] [and others

    1996-04-01

    An understanding of radiation transport (RT) through clouds is fundamental to studies of the earth`s radiation budget and climate dynamics. The transmission through horizontally homogeneous clouds has been studied thoroughly using accurate, discreet ordinates radiative transfer models. However, the applicability of these results to general problems of global radiation budget is limited by the plane parallel assumption and the fact that real clouds fields show variability, both vertically and horizontally, on all size scales. To understand how radiation interacts with realistic clouds, we have used a Monte Carlo radiative transfer model to compute the details of the photon-cloud interaction on synthetic cloud fields. Synthetic cloud fields, generated by a cascade model, reproduce the scaling behavior, as well as the cloud variability observed and estimated from cloud satellite data.

  18. The study of the radiation protection of propolis to the radiation effects in mice

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Y.H.; Suzuki, Ikukatsu; Hasegawa, Takeo; Muto, H. [Suzuka Univ. of Medical Science, Mie (Japan); Yanagisawa, Takaharu; Iwasa, Toshihiro; Bamen, K.

    2000-05-01

    The profit which radiation brought to the Homo sapiens is very big. But, radiation has even harmful parameter for the human besides one case. After effect on man to the radiation is thought about, the individual of which sensibility is the highest is a fetus. Therefore, even an effects to this fetus is grasped precisely, and protection criterion and resource are decided from the viewpoint of the protection of radiation as well. If it does so, a child and maturitas aren't so difficult as in the protection of radiation and the managerial side. It was examined about control group, propolis administration chisels for medical use group, 1.5 Gy independent exposure group and propolis pluse 1.5 Gy group in this study. It was examined about the protection of radiation of propolis which to malformation, fetal death, arrested development, and so on in the organogenesis (8 days post conception) being done when sensibility is the highest against the teratogenesis. Preimplantation death rate was compared with the control group and the sham control group, and statistical significant difference wasn't recognized by a 1.5 Gy radiation independent exposure group, propolis administration 1.5 Gy radiation exposure group. As for the embryonic death rate, propolis was administered, and obviously embryonic death rate was poorer than the 1.5 Gy independent exposure group, and significant difference was recognized by a 1.5 Gy radiation exposure group (p<0.001). It has a 1.5 Gy radiation exposure group made clear by this research fetal death rate propolis administer more only 1.5 Gy exposure fetal death rate development low (p<0.001). Fetal death rate wasn't recognized by propolis administration group (Sham control). As for the teratogenesis rate, propolis was administered, and the teratogenesis rate of the 1.5 Gy radiation exposure group was higher than the 1.5 Gy radiation independent exposure group. But, this is thought anamorphosis appear by propolis administration so

  19. Atomic photoelectron-spectroscopy studies using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kobrin, P.H.

    1983-02-01

    Photoelectron spectroscopy combined with tunable synchrotron radiation has been used to study the photoionization process in several atomic systems. The time structure of the synchrotron radiation source at the Stanford Synchrotron Radiation Laboratory (SSRL) was used to record time-of-flight (TOF) photoelectron spectra of gaseous Cd, Hg, Ne, Ar, Ba, and Mn. The use of two TOF analyzers made possible the measurement of photoelectron angular distributions as well as branching ratios and partial cross sections.

  20. SU-F-I-71: Fetal Protection During Fluoroscopy: To Shield Or Not to Shield?

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, S; Vanderhoek, M [Henry Ford Health System, Detroit, MI (United States)

    2016-06-15

    Purpose: Lead aprons are routinely used to shield the fetus from radiation during fluoroscopically guided interventions (FGI) involving pregnant patients. When placed in the primary beam, lead aprons often reduce image quality and increase fluoroscopic radiation output, which can adversely affect fetal dose. The purpose of this work is to identify an effective and practical method to reduce fetal dose without affecting image quality. Methods: A pregnant patient equivalent abdominal phantom is set on the table along with an image quality test object (CIRS model 903) representing patient anatomy of interest. An ion chamber is positioned at the x-ray beam entrance to the phantom, which is used to estimate the relative fetal dose. For three protective methods, image quality and fetal dose measurements are compared to baseline (no protection):1. Lead apron shielding the entire abdomen; 2. Lead apron shielding part of the abdomen, including the fetus; 3. Narrow collimation such that fetus is excluded from the primary beam. Results: With lead shielding the entire abdomen, the dose is reduced by 80% relative to baseline along with a drastic deterioration of image quality. With lead shielding only the fetus, the dose is reduced by 65% along with complete preservation of image quality, since the image quality test object is not shielded. However, narrow collimation results in 90% dose reduction and a slight improvement of image quality relative to baseline. Conclusion: The use of narrow collimation to protect the fetus during FGI is a simple and highly effective method that simultaneously reduces fetal dose and maintains sufficient image quality. Lead aprons are not as effective at fetal dose reduction, and if placed improperly, they can severely degrade image quality. Future work aims to investigate a wider variety of fluoroscopy systems to confirm these results across many different system geometries.

  1. Radiation protection in interventional radiology: survey results of attitudes and use.

    Science.gov (United States)

    Lynskey, G Emmett; Powell, Daniel K; Dixon, Robert G; Silberzweig, James E

    2013-10-01

    To assess attitudes of interventional radiologists toward personal radiation protection and the use of radiation protection devices. Invitations to an anonymous online survey that comprised eight questions focused on operator attitudes toward radiation protection devices were sent via e-mail to the active membership of the Society of Interventional Radiology (SIR): a total of 3,158 e-mail invitations. A single reminder e-mail was sent. There were 504 survey responders (16% response rate). Reported radiation safety device use included lead apron (99%), thyroid shield (94%), leaded eyeglasses (54%), ceiling-suspended leaded shield (44%), rolling leaded shields (12%), ceiling-suspended/rolling lead-equivalent apron (4%), radiation-attenuating sterile surgical gloves (1%), and sterile lead-equivalent patient-mounted drape (4%). Reasons commonly cited for not using certain devices were comfort (eyewear), ease of use (mounted shields), and lack of availability (rolling/hanging shields and patient-mounted shields). Interventionalists have an array of tools from which to choose for personal radiation protection; however, for a variety of reasons related to lack of availability or choice, these tools are not universally employed. Further study may be of value to clarify why comfort was cited most often as the primary barrier to the use of protective eyewear and difficulty of use was cited as the primary barrier to use of mounted shields (despite reporting that concern for radiation-induced injury to the eye is paramount). It may also be of interest to further study why certain devices with demonstrable protection effects are not readily available, such as rolling/hanging and patient-mounted shields. © SIR, 2013.

  2. Improved Spacecraft Materials for Radiation Protection

    Science.gov (United States)

    Wilson, John W.; Cucinotta, Francis A.; Tripathi, Ram K.; Clowdsley, M. S.; Shinn, J. L.; Singleterry, Robert C., Jr.; Thibeault, Sheila Ann; Kim, M.-H. Y.; Heinbockel, John H.; Badhwar, Gautam D.

    2001-01-01

    Sv limit for the exposure of the blood forming organs (this limit is strictly for LEO but can be used as a guideline for the Mars mission analysis). The current estimates require aluminum shield thicknesses above 50 g/sq cm., which is impractical. In such a heavily shielded vehicle, the neutrons produced throughout the vehicle also contribute significantly to the exposure and this demands greater care in describing the angular dependence of secondary particle production processes. As such the continued testing of databases and transport procedures in laboratory and spaceflight experiments has continued. This has been the focus of much of the last year's activity and has resulted in improved neutron prediction capability. These new methods have also improved our understanding of the surface environment of Mars. The Mars 2003 NRA HEDS related surface science requirements were driven by the need to validate predictions on the upward flux of neutrons produced in the Martian regolith and bedrock made by the codes developed under this project. The codes used in the surface environment definition are also being used to look at in situ resources for the development of construction material for Martian surface facilities. For example, synthesis of polyimides and polyethylene as binders of regolith for developing basic structural elements has been studied and targets built for accelerator beam testing of radiation shielding properties. Preliminary mechanical tests have also been promising. Improved spacecraft materials have been identified (using the criteria reported by this project at the last conference) as potentially important for future shielding materials. These are liquid hydrogen, hydrogenated nanofibers, liquid methane, LiH, Polyethylene, Polysulfone, and Polyetherimide (in order of decreasing shield performance). Some of the materials are multifunctional and are required for other onboard systems. We are currently preparing software for trade studies with these materials

  3. Roof Shield for Advance and Retreat Mining

    Science.gov (United States)

    Lewis, E. V.

    1985-01-01

    Shield sections change their configuration to suit mining mode. Articulation cylinders raise rear shield to advance position, and locking cylinders hold it there. To change to retreat position articulation cylinders lower shield. Locking pins at edge of outermost shield plate latch shield to chock base. Shield accommodates roof heights ranging from 36 to 60 inches (0.9 to 1.52 meters).

  4. Organ dose assessment of nuclear medicine practitioners using L-block shielding device for handing diagnostic radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Se Sik; Kim, Jung Hoon [Dep. of Radiological Science, College of Health Science, Catholic University of Pusan, Busan (Korea, Republic of); Cho, Yong In [Dept. of Diagnostic Radiology, Dongnam Institute of Radiological and Medical Science, Busan (Korea, Republic of)

    2017-03-15

    In the case of nuclear medicine practitioners in medical institutions, a wide range of exposure dose to individual workers can be found, depending on the type of source, the amount of radioactivity, and the use of shielding devices in handling radioactive isotopes. In this regard, this study evaluated the organ dose on practitioners as well as the dose reduction effect of the L-block shielding device in handling the diagnostic radiation source through the simulation based on the Monte Carlo method. As a result, the distribution of organ dose was found to be higher as the position of the radiation source was closer to the handling position of a practitioner, and the effective dose distribution was different according to the ICRP tissue weight. Furthermore, the dose reduction effect according to the L-block thickness tended to decrease, which showed the exponential distribution, as the shielding thickness increased. The dose reduction effect according to each radiation source showed a low shielding effect in proportion to the emitted gamma ray energy level.

  5. Studies on EB radiation effect on PA610

    Energy Technology Data Exchange (ETDEWEB)

    Yang Kebin; Zhang Huaming; Li Xiurong; Xiong Ruilin [Sichuan Forever Group Co. Ltd., China Academy of Engineering Physics, Miangany (China)

    2000-03-01

    Radiation effect of PA610 with polyfunctional monomer trially isocyanurate (TAIC) was studied, the results show that crosslinking effect of EB radiation on PA610 is obvious. After the PA610 samples were radiated by EB with dosage 75KGY, the physical characters of PA610 materials were greatly improved, especially their tensile strength being increased about 18% and their impact strength about 50%, but their water and oil absorption were decreased. So, EB radiation can enhance PA610 materials physical strength, resistance to solvents and water and increase their thermal-deformation temperature. (author)

  6. Lack of radiation protection for endoscopists performing endoscopic retrograde cholangiopancreatography.

    Science.gov (United States)

    Son, Byoung Kwan; Lee, Kyu Taek; Kim, Jae Seon; Lee, Seung Ok

    2011-12-01

    ERCP using fluoroscopy should be practiced with an adequate radiation protection. However, the awareness of gastrointestinal endoscopists to radiation protection was considered insufficient. In Korea, a country with a rapid increase the number of ERCP procedures, there is no data about radiation protection practices for gastrointestinal endoscopists. The purpose of this study was to investigate current clinical practices and the awareness on radiation protection in ERCP performing physicians in Korea. An anonymous questionnaire regarding radiation protection practices was mailed to 100 members of Korean Pancreatobiliary Association who was porforming ERCP. The questionnaire included ERCP volume of each endoscopist, use of protection devices such as apron, thyroid shield, lead glasses and any mobile shield for scattered radiation, and whether they monitored their own radiation exposure dosage. All respondents wore lead aprons during ERCP. While 52.5% of endoscopists answered that they always wear thyroid guards, 26.9% rarely or never wore it. Only 14% wore lead glasses during the procedure and 69% never wore it. The preparation rates of mobile shields or lead curtains were only 14% and 24%, respectively. Only 10% of endoscopists attached an X-ray badge and 66.7% never used it. Moreover, 75% of endoscopists responded that they did not monitor their own exposure dose to radiation during ERCP. The lack of radiation protection of ERCP endoscopists in Korea was seemed serious. Awareness of radiation hazard should be more concerned and educated in parallel with the preparation of radiation protection equipments.

  7. Light shielding apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Richard Dean; Thom, Robert Anthony

    2017-10-10

    A light shielding apparatus for blocking light from reaching an electronic device, the light shielding apparatus including left and right support assemblies, a cross member, and an opaque shroud. The support assemblies each include primary support structure, a mounting element for removably connecting the apparatus to the electronic device, and a support member depending from the primary support structure for retaining the apparatus in an upright orientation. The cross member couples the left and right support assemblies together and spaces them apart according to the size and shape of the electronic device. The shroud may be removably and adjustably connectable to the left and right support assemblies and configured to take a cylindrical dome shape so as to form a central space covered from above. The opaque shroud prevents light from entering the central space and contacting sensitive elements of the electronic device.

  8. Beam line shielding calculations for an Electron Accelerator Mo-99 production facility

    Energy Technology Data Exchange (ETDEWEB)

    Mocko, Michal [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-03

    The purpose of this study is to evaluate the photon and neutron fields in and around the latest beam line design for the Mo-99 production facility. The radiation dose to the beam line components (quadrupoles, dipoles, beam stops and the linear accelerator) are calculated in the present report. The beam line design assumes placement of two cameras: infra red (IR) and optical transition radiation (OTR) for continuous monitoring of the beam spot on target during irradiation. The cameras will be placed off the beam axis offset in vertical direction. We explored typical shielding arrangements for the cameras and report the resulting neutron and photon dose fields.

  9. Gas bremsstrahlung shielding calculation for first optic enclosure of ILSF XPD beamline.

    Science.gov (United States)

    Beigzadeh Jalali, H; Salimi, E; Rahighi, J

    2017-11-01

    Gas bremsstrahlung is generated in high energy electron storage ring and accompanies the synchrotron radiation into the beamlines, where both strike the various components of the beamline. In this paper, radiation shielding calculations for secondary gas bremsstrahlung are performed for the First Optics Enclosure (FOE) of X-ray powder diffraction (XPD) beamline of the Iranian Light Source Facility. Dose equivalent rate (DER) calculations are accomplished using FLUKA Monte Carlo code. A comprehensive study of DER distribution at the back wall, sides and roof are given. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Adaptive statistical iterative reconstruction and bismuth shielding for evaluation of dose reduction to the eye and image quality during head CT

    Science.gov (United States)

    Kim, Myeong Seong; Choi, Jiwon; Kim, Sun Young; Kweon, Dae Cheol

    2014-03-01

    There is a concern regarding the adverse effects of increasing radiation doses due to repeated computed tomography (CT) scans, especially in radiosensitive organs and portions thereof, such as the lenses of the eyes. Bismuth shielding with an adaptive statistical iterative reconstruction (ASIR) algorithm was recently introduced in our clinic as a method to reduce the absorbed radiation dose. This technique was applied to the lens of the eye during CT scans. The purpose of this study was to evaluate the reduction in the absorbed radiation dose and to determine the noise level when using bismuth shielding and the ASIR algorithm with the GE DC 750 HD 64-channel CT scanner for CT of the head of a humanoid phantom. With the use of bismuth shielding, the noise level was higher in the beam-hardening artifact areas than in the revealed artifact areas. However, with the use of ASIR, the noise level was lower than that with the use of bismuth alone; it was also lower in the artifact areas. The reduction in the radiation dose with the use of bismuth was greatest at the surface of the phantom to a limited depth. In conclusion, it is possible to reduce the radiation level and slightly decrease the bismuth-induced noise level by using a combination of ASIR as an algorithm process and bismuth as an in-plane hardware-type shielding method.

  11. Adaptive statistical iterative reconstruction and bismuth shielding for evaluation of dose reduction to the eye and image quality during head CT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Myeong Seong [The Korean National Cancer Center, Goyang (Korea, Republic of); Seoul National University, Seoul (Korea, Republic of); Choi, Ji Won [Jeonju University, Jeonju (Korea, Republic of); Kim, Sun Young [Hallym University of Graduate Studies, Seoul (Korea, Republic of); The Korean National Cancer Center, Goyang (Korea, Republic of); Kweon, Dae Cheol [Shinhan University, Uijeongbu (Korea, Republic of)

    2014-03-15

    There is a concern regarding the adverse effects of increasing radiation doses due to repeated computed tomography (CT) scans, especially in radiosensitive organs and portions thereof, such as the lenses of the eyes. Bismuth shielding with an adaptive statistical iterative reconstruction (ASIR) algorithm was recently introduced in our clinic as a method to reduce the absorbed radiation dose. This technique was applied to the lens of the eye during CT scans. The purpose of this study was to evaluate the reduction in the absorbed radiation dose and to determine the noise level when using bismuth shielding and the ASIR algorithm with the GE DC 750 HD 64-channel CT scanner for CT of the head of a humanoid phantom. With the use of bismuth shielding, the noise level was higher in the beam-hardening artifact areas than in the revealed artifact areas. However, with the use of ASIR, the noise level was lower than that with the use of bismuth alone; it was also lower in the artifact areas. The reduction in the radiation dose with the use of bismuth was greatest at the surface of the phantom to a limited depth. In conclusion, it is possible to reduce the radiation level and slightly decrease the bismuth-induced noise level by using a combination of ASIR as an algorithm process and bismuth as an in-plane hardware-type shielding method.

  12. Geometrical aspects of cylindric magnetic shields in strong static fields

    Science.gov (United States)

    Zhiwei, XIA; Wei, LI; Bo, LI; Qingwei, YANG

    2017-11-01

    Motivated by ITER (the International Thermonuclear Experimental Reactor), research on a magnetic shield against a strong field has been carried out. In this paper, a cylindric magnetic shield is studied by using the finite element method with a nonlinear magnetization curve. The geometrical aspects of shielding performance are identified and corresponding suggestions for application are provided. Among them, the effects of the edge and cover thickness have not been mentioned elsewhere to our knowledge.

  13. Multihelix rotating shield brachytherapy for cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Dadkhah, Hossein [Department of Biomedical Engineering, University of Iowa, 1402 Seamans Center for the Engineering Arts and Sciences, Iowa City, Iowa 52242 (United States); Kim, Yusung; Flynn, Ryan T., E-mail: ryan-flynn@uiowa.edu [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States); Wu, Xiaodong [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 and Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center for the Engineering Arts and Sciences, Iowa City, Iowa 52242 (United States)

    2015-11-15

    Purpose: To present a novel brachytherapy technique, called multihelix rotating shield brachytherapy (H-RSBT), for the precise angular and linear positioning of a partial shield in a curved applicator. H-RSBT mechanically enables the dose delivery using only linear translational motion of the radiation source/shield combination. The previously proposed approach of serial rotating shield brachytherapy (S-RSBT), in which the partial shield is rotated to several angular positions at each source dwell position [W. Yang et al., “Rotating-shield brachytherapy for cervical cancer,” Phys. Med. Biol. 58, 3931–3941 (2013)], is mechanically challenging to implement in a curved applicator, and H-RSBT is proposed as a feasible solution. Methods: A Henschke-type applicator, designed for an electronic brachytherapy source (Xoft Axxent™) and a 0.5 mm thick tungsten partial shield with 180° or 45° azimuthal emission angles and 116° asymmetric zenith angle, is proposed. The interior wall of the applicator contains six evenly spaced helical keyways that rigidly define the emission direction of the partial radiation shield as a function of depth in the applicator. The shield contains three uniformly distributed protruding keys on its exterior wall and is attached to the source such that it rotates freely, thus longitudinal translational motion of the source is transferred to rotational motion of the shield. S-RSBT and H-RSBT treatment plans with 180° and 45° azimuthal emission angles were generated for five cervical cancer patients with a diverse range of high-risk target volume (HR-CTV) shapes and applicator positions. For each patient, the total number of emission angles was held nearly constant for S-RSBT and H-RSBT by using dwell positions separated by 5 and 1.7 mm, respectively, and emission directions separated by 22.5° and 60°, respectively. Treatment delivery time and tumor coverage (D{sub 90} of HR-CTV) were the two metrics used as the basis for evaluation and

  14. Gamma radiation in ceramic capacitors: a study for space missions

    Science.gov (United States)

    dos Santos Ferreira, Eduardo; Sarango Souza, Juliana

    2017-10-01

    We studied the real time effects of the gamma radiation in ceramic capacitors, in order to evaluate the effects of cosmic radiation on these devices. Space missions have electronic circuits with various types of devices, many studies have been done on semiconductor devices exposed to gamma radiation, but almost no studies for passive components, in particular ceramic capacitors. Commercially sold ceramic capacitors were exposed to gamma radiation, and the capacitance was measured before and after exposure. The results clearly show that the capacitance decreases with exposure to gamma radiation. We confirmed this observation in a real time capacitance measurement, obtained using a data logging system developed by us using the open source Arduino platform.

  15. Film type SO-168 radiation study

    Science.gov (United States)

    Pierce, W. N.

    1972-01-01

    Investigations were performed to determine optimum exposure and processing procedures necessary to partially offset the effect of radiation to which film type SO-168 will be exposed during the Skylab Mission. This task became necessary when it was determined that original predictions of 2 to 3 RADS of radiation to which the film will be exposed were too low, and that levels as high as 3.5 to 4.0 RADS may be incurred, thus reducing image quality below an acceptable level. Tests results show that forced processing of type SO-168 film tended to reduce the density range to an unusable level, and that processing to a lower ASA value would provide greater image quality for the user.

  16. RadShield: semiautomated shielding design using a floor plan driven graphical user interface.

    Science.gov (United States)

    DeLorenzo, Matthew C; Wu, Dee H; Yang, Kai; Rutel, Isaac B

    2016-09-08

    The purpose of this study was to introduce and describe the development of RadShield, a Java-based graphical user interface (GUI), which provides a base design that uniquely performs thorough, spatially distributed calculations at many points and reports the maximum air-kerma rate and barrier thickness for each barrier pursuant to NCRP Report 147 methodology. Semiautomated shielding design calculations are validated by two approaches: a geometry-based approach and a manual approach. A series of geometry-based equations were derived giv-ing the maximum air-kerma rate magnitude and location through a first derivative root finding approach. The second approach consisted of comparing RadShield results with those found by manual shielding design by an American Board of Radiology (ABR)-certified medical physicist for two clinical room situations: two adjacent catheterization labs, and a radiographic and fluoroscopic (R&F) exam room. RadShield's efficacy in finding the maximum air-kerma rate was compared against the geometry-based approach and the overall shielding recommendations by RadShield were compared against the medical physicist's shielding results. Percentage errors between the geometry-based approach and RadShield's approach in finding the magnitude and location of the maximum air-kerma rate was within 0.00124% and 14 mm. RadShield's barrier thickness calculations were found to be within 0.156 mm lead (Pb) and 0.150 mm lead (Pb) for the adjacent catheteriza-tion labs and R&F room examples, respectively. However, within the R&F room example, differences in locating the most sensitive calculation point on the floor plan for one of the barriers was not considered in the medical physicist's calculation and was revealed by the RadShield calculations. RadShield is shown to accurately find the maximum values of air-kerma rate and barrier thickness using NCRP Report 147 methodology. Visual inspection alone of the 2D X-ray exam distribution by a medical physicist may not

  17. Thermoforming plastic in lead shield construction.

    Science.gov (United States)

    Abrahams, M E; Chow, C H; Loyd, M D

    1989-09-01

    Radiation treatments using low energy X-rays or electrons frequently require a final field defining shield to be placed on the patient's skin. A custom made lead cut-out is used to provide a close fit to a particular patient's surface contours. We have developed a procedure which utilizes POLYFORM thermoplastic to obtain a negative mold of the patient instead of the traditional plaster bandage or dental impression gel. The Polyform is softened in warm water, molded carefully over the patient's surface, and is removed when "set" or hardened, usually within five minutes. Then lead sheet cut-outs can be formed within this negative. For shielding cut-outs requiring thicker lead sheet, a positive is made from dental stone using this Polyform negative. We have found this procedure to be neat, fast and comfortable for both patient and the dosimetrist.

  18. Thermoforming plastic in lead shield construction

    Energy Technology Data Exchange (ETDEWEB)

    Abrahams, M.E.; Chow, C.H.; Loyd, M.D. (Univ. of Texas Medical Branch, Galveston (USA))

    1989-09-01

    Radiation treatments using low energy X-rays or electrons frequently require a final field defining shield to be placed on the patient's skin. A custom made lead cut-out is used to provide a close fit to a particular patient's surface contours. We have developed a procedure which utilizes POLYFORM thermoplastic to obtain a negative mold of the patient instead of the traditional plaster bandage or dental impression gel. The Polyform is softened in warm water, molded carefully over the patient's surface, and is removed when set or hardened, usually within five minutes. Then lead sheet cut-outs can be formed within this negative. For shielding cut-outs requiring thicker lead sheet, a positive is made from dental stone using this Polyform negative. We have found this procedure to be neat, fast and comfortable for both patient and the dosimetrist.

  19. Grounding and shielding circuits and interference

    CERN Document Server

    Morrison, Ralph

    2016-01-01

    Applies basic field behavior in circuit design and demonstrates how it relates to grounding and shielding requirements and techniques in circuit design This book connects the fundamentals of electromagnetic theory to the problems of interference in all types of electronic design. The text covers power distribution in facilities, mixing of analog and digital circuitry, circuit board layout at high clock rates, and meeting radiation and susceptibility standards. The author examines the grounding and shielding requirements and techniques in circuit design and applies basic physics to circuit behavior. The sixth edition of this book has been updated with new material added throughout the chapters where appropriate. The presentation of the book has also been rearranged in order to reflect the current trends in the field.

  20. Deoxyribonucleic acid-Ag nanoparticles for EMI Shielding: the effect of nanoparticle size, shape and distribution on the shielding effectiveness

    Science.gov (United States)

    Ouchen, Fahima; Wilson, Benjamin G.; Yaney, Perry P.; Salour, Michael M.; Grote, James G.

    2014-09-01

    This study focuses on the use of silver based nanoparticle as fillers in DNA host materials to form nancomposites for applications in Electro-Magnetic Interferences (EMI) shielding. For relatively low-conductivity EMI shielding nanocomposites, silver-oxide coated cenospheres are investigated as fillers. The filler loadings are varied to determine a percolation threshold for the desired low conductivity and shielding effectiveness. Microwave absorption as well as DC surface resistivity measurements are undertaken to characterize the obtained films.

  1. Physical analysis of the shielding capacity for a lightweight apron designed for shielding low intensity scattering X-rays

    Science.gov (United States)

    Kim, Seon Chil; Choi, Jeong Ryeol; Jeon, Byeong Kyou

    2016-07-01

    The purpose of this paper is to develop a lightweight apron that will be used for shielding low intensity radiation in medical imaging radiography room and to apply it to a custom-made effective shielding. The quality of existing aprons made for protecting our bodies from direct radiation are improved so that they are suitable for scattered X-rays. Textiles that prevent bodies from radiation are made by combining barium sulfate and liquid silicon. These materials have the function of shielding radiation in a manner like lead. Three kinds of textiles are produced. The thicknesses of each textile are 0.15 mm, 0.21 mm, and 0.29 mm and the corresponding lead equivalents are 0.039 mmPb, 0.095 mmPb, 0.22 mmPb for each. The rate of shielding space scattering rays are 80% from the distance of 0.5 m, 86% from 1.0 m, and 97% from 1.5 m. If we intend to approach with the purpose of shielding scattering X-rays and low intensity radiations, it is possible to reduce the weight of the apron to be 1/5 compared to that of the existing lead aprons whose weight is typically more than 4 kg. We confirm, therefore, that it is possible to produce lightweight aprons that are used for the purpose of shielding low dose radiations.

  2. Effect of metal shielding on a wireless power transfer system

    Science.gov (United States)

    Li, Jiacheng; Huang, Xueliang; Chen, Chen; Tan, Linlin; Wang, Wei; Guo, Jinpeng

    2017-05-01

    In this paper, the effect of non-ferromagnetic metal shielding (NFMS) material on the resonator of wireless power transfer (WPT) is studied by modeling, simulation and experimental analysis. And, the effect of NFMS material on the power transfer efficiency (PTE) of WPT systems is investigated by circuit model. Meanwhile, the effect of ferromagnetic metal shielding material on the PTE of WPT systems is analyzed through simulation. A double layer metal shield structure is designed. Experimental results demonstrate that by applying the novel double layer metal shielding method, the system PTE increases significantly while the electromagnetic field of WPT systems declines dramatically.

  3. Electromagnetic shielding effectiveness of 3D printed polymer composites

    Science.gov (United States)

    Viskadourakis, Z.; Vasilopoulos, K. C.; Economou, E. N.; Soukoulis, C. M.; Kenanakis, G.

    2017-12-01

    We report on preliminary results regarding the electromagnetic shielding effectiveness of various 3D printed polymeric composite structures. All studied samples were fabricated using 3D printing technology, following the fused deposition modeling approach, using commercially available filaments as starting materials. The electromagnetic shielding performance of the fabricated 3D samples was investigated in the so called C-band of the electromagnetic spectrum (3.5-7.0 GHz), which is typically used for long-distance radio telecommunications. We provide evidence that 3D printing technology can be effectively utilized to prepare operational shields, making them promising candidates for electromagnetic shielding applications for electronic devices.

  4. Implementing Dust Shielding as a Criteria for Star Formation

    Science.gov (United States)

    Byrne, Lindsey; Christensen, Charlotte

    2018-01-01

    Star formation is observed to occur in dense regions of molecular gas. Although the exact nature of the link between star formation and molecular hydrogen is still unclear, it has been suggested that dust shielding of dense gas is the key factor enabling the presence of both. We present a model in which star formation is linked explicitly to local dust shielding, rather than molecular hydrogen abundance, in smoothed particle hydrodynamics galaxy formation simulations. We used simulations of isolated Milky-Way-mass disk galaxies to develop a dust shielding model in which the radiative shielding length was based off of the Jeans length with a T=40 K temperature cap. Using this shielding model, we compare the effects of different star formation recipes, including recipes in which star formation is based on the amount of dust shielding or the local molecular hydrogen abundance. We test our star formation models on two sets of isolated disk galaxies with solar and sub-solar metallicities and on a cosmological dwarf galaxy simulation. We find that the shielding-based model can reproduce the observed transition from atomic to molecular hydrogen at realistic surface densities, exhibits periodic bursts of star formation, and allows for star formation at higher temperatures and lower densities than a model in which star formation is tied directly to H2 abundance.

  5. Radiation Shielding Using Thermally Insulating Spheres Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The design of future habitation structures and exploration vehicles will require a higher level of crew protection from dangerous solar particle events (SPE) and...

  6. Polybenzoxazine Materials for Radiation Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed work will develop lightweight multifunctional composite materials based on high hydrogen content polybenzoxazine (PBZ) composites that provide excellent...

  7. A contribution to shielding effectiveness analysis of shielded tents

    Directory of Open Access Journals (Sweden)

    Vranić Zoran M.

    2004-01-01

    Full Text Available An analysis of shielding effectiveness (SE of the shielded tents made of the metallised fabrics is given. First, two electromagnetic characteristic fundamental for coupling through electrically thin shield, the skin depth break frequency and the surface resistance or transfer impedance, is defined and analyzed. Then, the transfer function and the SE are analyzed regarding to the frequency range of interest to the Electromagnetic Compatibility (EMC Community.

  8. Measurement of the transient shielding effectiveness of shielding cabinets

    Directory of Open Access Journals (Sweden)

    H. Herlemann

    2008-05-01

    Full Text Available Recently, new definitions of shielding effectiveness (SE for high-frequency and transient electromagnetic fields were introduced by Klinkenbusch (2005. Analytical results were shown for closed as well as for non closed cylindrical shields. In the present work, the shielding performance of different shielding cabinets is investigated by means of numerical simulations and measurements inside a fully anechoic chamber and a GTEM-cell. For the GTEM-cell-measurements, a downscaled model of the shielding cabinet is used. For the simulations, the numerical tools CONCEPT II and COMSOL MULTIPHYSICS were available. The numerical results agree well with the measurements. They can be used to interpret the behaviour of the shielding effectiveness of enclosures as function of frequency. From the measurement of the electric and magnetic fields with and without the enclosure in place, the electric and magnetic shielding effectiveness as well as the transient shielding effectiveness of the enclosure are calculated. The transient SE of four different shielding cabinets is determined and discussed.

  9. Topics in radiation at accelerators: Radiation physics for personnel and environmental protection

    Energy Technology Data Exchange (ETDEWEB)

    Cossairt, J.D.

    1993-11-01

    This report discusses the following topics: Composition of Accelerator Radiation Fields; Shielding of Electrons and Photons at Accelerators; Shielding of Hadrons at Accelerators; Low Energy Prompt Radiation Phenomena; Induced Radioactivity at Accelerators; Topics in Radiation Protection Instrumentation at Accelerators; and Accelerator Radiation Protection Program Elements.

  10. Evaluation of the efficacy of pelvic shielding in preadolescent girls.

    Science.gov (United States)

    Liakos, P; Schoenecker, P L; Lyons, D; Gordon, J E

    2001-01-01

    A standing anteroposterior pelvic radiograph with gonadal shielding is used as a screening tool for all patients evaluated for intoeing at our institution. Sixty-two normal consecutive screening pelvic radiographs obtained in 61 female patients between the ages of 4 and 6 years were evaluated. Radiographs were evaluated for the adequacy to assess the hips as well as the protection afforded the ovaries from radiation exposure. Radiographs were judged to be inadequate because the shield covered essential landmarks in at least one hip in eight radiographs (13%). Five radiographs (8%) covered >50% of the area of both ovaries, and only one radiograph covered >75% of the area of both ovaries. Standard techniques of positioning gonadal shields in preadolescent girls are inadequate and provide minimal protection with a high rate of interference with vital landmarks. We no longer advocate using gonadal shields on initial screening radiographs of preadolescent girls.

  11. A Shielding Concept for the MedAustron Facility

    Science.gov (United States)

    Jägerhofer, L.; Feldbaumer, E.; Roesler, S.; Theis, C.; Vincke, H.

    2017-09-01

    MedAustron is a synchrotron based accelerator facility for cancer therapy and research in Wiener Neustadt, 50 km south of Vienna. The facility will provide protons up to kinetic energies of 250 MeV and carbon ions up to 400 MeV/n for ion beam therapy. Additionally, protons up to 800 MeV kinetic energy will be used in a dedicated room for non-clinical research. In order to obtain a shielding concept for this facility a detailed geometry of the accelerator facility was implemented into the Monte-Carlo code FLUKA and shielding simulations were performed. In the course of these simulations the contributions of different particle types to the mixed fields around the accelerator and behind shielding were analysed. In an iterative process with the architect the final design of the shielding concept was developed until it was capable of reducing the effect of secondary radiation on humans and the environment below Austrian legal limits.

  12. [The study of transpiration influence on plant infrared radiation character].

    Science.gov (United States)

    Ling, Jun; Zhang, Shuan-Qin; Pan, Jia-Liang; Lian, Chang-Chun; Yang, Hui

    2012-07-01

    Studying vegetation infrared radiation character is the base of developing infrared camouflage and concealment technology of ground military target. Accurate fusion of target and background can be achieved by simulating formation mechanism of vegetation infrared radiation character. Leaf transpiration is characteristic physiological mechanism of vegetation and one of the main factors that influence its infrared radiation character. In the present paper, physical model of leaf energy balance is set up. Based on this model the influence of plant transpiration on leaf temperature is analyzed and calculated. The daily periodic variation of transpiration, leaf temperature and infrared radiation character of typical plants such as camphor tree and holly is actually measured with porometer and infrared thermal imaging system. By contrasting plant leaf with dryness leaf, experimental data indicates that plant transpiration can regulate leaf energy balance effectively and control leaf temperature in a reasonable range and suppress deep range variation of leaf infrared radiation character.

  13. Study of electromagnetic radiation pollution in Jalandhar city, India

    Science.gov (United States)

    Basandrai, D.; Dhami, A. K.; Bedi, R. K.; Khan, S. A.

    2017-07-01

    Environment pollution from electromagnetic radiations emitted from cell phone towers is a new kind of health hazard, which has increase the public concern regarding the health implications of electromagnetic radiations on humans and animals. Long term consequences of these radiations are still unknown. So it become important to measure and maps the electromagnetic radiation level to analyze potential risk. The present study has been taken to estimate the RF pollution by measuring radiation power densities level near school, hospitals and old age home of Jalandhar City, India. The radiation exposure was measured using a handheld portable electrosmog meter. Results were compared with the safety guidelines issued by ICNIRP (International commission on non ionizing radiation protection) and Bio-initiative report, 2012. It has been found that the radiation exposure level in terms of power densities and corresponding specific absorption rate (SAR) are much below than ICNIRP guidelines for all schools, hospitals and old age home. But in the case of 3 schools, the results are quite alarming where the power density and SAR was found to be 79.6% and 4%, respectively higher in comparisons with safe biological limit.

  14. Neutron shielding for a {sup 252} Cf source

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M. [Unidades Academicas de Estudios Nucleares e Ingenieria Electrica, Universidad Autonoma de Zacatecas, C. Cipres 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Eduardo Gallego, Alfredo Lorente [Depto. de Ingenieria Nuclear, ETS Ingenieros Industriales, Universidad Politecnica de Madrid, C. Jose Gutierrez Abascal 2, 28006 Madrid (Spain)]. e-mail: fermineutron@yahoo.com

    2006-07-01

    To determine the neutron shielding features of water-extended polyester a Monte Carlo study was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through inelastic collisions and absorption reactions. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide production induced by neutron activation must be considered. In this investigation the Monte Carlo method was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a {sup 252}Cf isotopic neutron source. During calculations a detailed model for the {sup 252}Cf and the shield was utilized. To compare the shielding features of water extended polyester, the calculations were also made for the bare {sup 252}Cf in vacuum, air and the shield filled with water. For all cases the calculated neutron spectra was utilized to determine the ambient equivalent neutron dose at four sites around the shielding. In the case of water extended polyester and water shielding the calculations were extended to include the prompt gamma rays produced during neutron interactions, with this information the Kerma in air was calculated at the same locations where the ambient equivalent neutron dose was determined. (Author)

  15. Study on technology for minimizing radiation risk

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Ho; Kim, In Gyu; Kim, Jin Kyu; Lee, Kang Suk; Kim, Kug Chan; Chun, Ki Chung

    1997-01-01

    Apoptosis, also called programmed cell death to discriminate it from necrosis, is characterized by : chromatin condensation, apoptotic body formation, fragmentation of DNA into oligonucleosome sized pieces, swelling and progressive cell degradation. We examined morphological and biochemical changes of T-lymphocytes following gamma irradiation exposure. The results are followings. (1) Murine lymphocytes have several characteristics : The irradiated cells undergo morphological and biochemical changes characteristic of apoptosis, causing growth delay. (0.01, 0.1, 1.0 Gy) (2) The onset of DNA fragmentation in cells occurs after one more cell divisions. (3) DNA fragmentation in cells occurs in all irradiated group (0.1, 1.0, 2.0, 4.0 Gy, 24 hours following gamma radiation exposure) (4) Apoptotic bodies were detected by confocal microscope with ease when compared with electron microscope. For the developing technology for minimizing radiation damage, the following experimental works have been done. (1) Establishment of experimental system for pre-screening of radioprotectants - Screening of protective substances using TSH bioindicator - Efficacy test of some radioprotective materials (2) TSH bioindicator system can make a scientific role in screening unknown materials for their possible radioprotective effect. (author). 42 refs., 3 tabs., 9 figs.

  16. Radiation damage studies of silicon microstrip sensors

    CERN Document Server

    Nakayama, T; Hara, K; Shimojima, M; Ikegami, Y; Iwata, Y; Johansen, L G; Kobayashi, H; Kohriki, T; Kondo, T; Nakano, I; Ohsugi, T; Riedler, P; Roe, S; Stapnes, Steinar; Stugu, B; Takashima, R; Tanizaki, K; Terada, S; Unno, Y; Yamamoto, K; Yamamura, K

    2000-01-01

    Various types of large area silicon microstrip detectors were fabricated for the development of radiation-tolerant detectors that will operate in the LHC ATLAS SCT. The detectors were irradiated with 12-GeV protons at KEK to fluences of 1.7*10/sup 14/ and 4.2*10/sup 14 / protons/cm/sup 2/. Irradiated samples included n-on-n detectors with 4 k Omega cm bulk resistivity and p-on-n detectors with 1 k Omega cm and 4 k Omega cm bulk resistivities. Four patterns of p-stop structures are configured in the n-on-n detectors. Although Hamamatsu fabricated most of the detectors, p-on-n detectors by SINTEF are also included, as well as those fabricated in a modified process by Hamamatsu. The detector performances after irradiation that are compared are the probability of creation of faulty coupling capacitors, C-V characteristics, charge curves, and total leakage current. The p-on-n are similar to the n-on-n detectors in these performances, and will remain operational in the ATLAS radiation environment. (12 refs).

  17. Effect of a Real-Time Radiation Monitoring Device on Operator Radiation Exposure During Cardiac Catheterization: The Radiation Reduction During Cardiac Catheterization Using Real-Time Monitoring Study

    National Research Council Canada - National Science Library

    Christopoulos, Georgios; Papayannis, Aristotelis C; Alomar, Mohammed; Kotsia, Anna; Michael, Tesfaldet T; Rangan, Bavana V; Roesle, Michele; Shorrock, Deborah; Makke, Lorenza; Layne, Ronald; Grabarkewitz, Rebecca; Haagen, Donald; Maragkoudakis, Spyros; Mohammad, Atif; Sarode, Karan; Cipher, Daisha J; Chambers, Charles E; Banerjee, Subhash; Brilakis, Emmanouil S

    2014-01-01

    BACKGROUND—The Radiation Reduction During Cardiac Catheterization Using Real-Time Monitoring study sought to examine the effect of a radiation detection device that provides real-time operator dose reporting...

  18. Radiative Transfer Study of Exposure of Terrestrial and Martian Organisms During a Large Solar Flare

    Science.gov (United States)

    Scalo, J.; Smith, D. S.; Wheeler, J. C.

    2003-05-01

    We have developed a Monte Carlo code for calculations of the transport of high-energy irradiation of the atmospheres of ancient and contemporary Earth and Mars by solar flares and stellar explosions. We have calculated the dose spectrum to which surface organisms would be exposed during a large solar flare. We include details of Compton scattering and X-ray photoabsorption and an approximate treatment of the redistribution of the incident energy to ultraviolet and visible radiation by secondary electron excitation of atmospheric molecules, and its transfer to the surface, using Rayleigh scattering and scaled terrestrial ozone distribution as examples of UV shields. We find that for thick atmospheres (column densities greater than about 100 g/cm2 much of the incident ionizing radiation can be redistributed to biologically and chemically important ultraviolet wavelengths, a significant fraction of which can reach the surface. This radiation will consist primarily of a large number of auroral-like emission bands. This result is relevant to Earth and early Mars. For contemporary Mars, most of the energy reaches the surface as X-rays due to Compton scattering and photoabsorption, with a characteristic spectrum that is essentially independent of atmospheric composition. We calculate the dose per unit flare energy for water and for a DNA action spectrum, and we estimate the frequency of biologically significant flares from the Sun at Mars as a function of time using present-day flare statistics and studies of solar proxies of various ages. The question of sterilization of exposed organisms at the Martian surface is discussed using lethal dose data for prokaryotic and eukaryotic terrestrial organisms.

  19. Design for CubeSat-based dust and radiation studies at Europa

    Science.gov (United States)

    Goel, Ashish; Krishnamoorthy, Siddharth; Swenson, Travis; West, Stephen; Li, Alan; Crew, Alexander; Phillips, Derek James; Screve, Antoine; Close, Sigrid

    2017-07-01

    Europa is one of the icy moons of Jupiter and the possibility of an ocean of liquid water beneath its icy crust makes it one of the most fascinating destinations for exploration in the solar system. NASA's Europa Multiple Flyby Mission (EMFM, formerly Europa Clipper) is slated to visit the icy moon in a timeframe near the year 2022 to study the habitability of Europa. CubeSats carried along by the primary mission can supplement the measurements made, at a relatively low cost, and with the added benefits of involving students at universities in this challenging endeavor. Further, such a mission holds the key to extending the applicability of CubeSats to interplanetary missions. In this paper, we present the design of the Europa Radiation and Dust Observation Satellite (ERDOS), a 3U CubeSat designed to be deployed by the Europa Multiple Flyby Mission to carry out measurements of the radiation and dust environment, before impacting Europa's surface. We present a detailed design for a CubeSat-based secondary mission, and discuss the science goals that may be accomplished by such a mission. Further, we discuss results from a comprehensive analysis of various engineering challenges associated with an interplanetary CubeSat mission, such as radiation shielding and thermal environment control. Our results show that a short duration CubeSat-based flyby mission is feasible when the CubeSat is carried on board the primary mission until the Jovian system is reached. Such a flyby mission can provide important supplementary information to the primary mission about Europa's environment at a closer range and lead to a substantial increase in scientific knowledge about surface processes on Europa.

  20. Trade Study of System Level Ranked Radiation Protection Concepts for Deep Space Exploration

    Science.gov (United States)

    Cerro, Jeffrey A

    2013-01-01

    A strategic focus area for NASA is to pursue the development of technologies which support exploration in space beyond the current inhabited region of low earth orbit. An unresolved issue for crewed deep space exploration involves limiting crew radiation exposure to below acceptable levels, considering both solar particle events and galactic cosmic ray contributions to dosage. Galactic cosmic ray mitigation is not addressed in this paper, but by addressing credible, easily implemented, and mass efficient solutions for the possibility of solar particle events, additional margin is provided that can be used for cosmic ray dose accumulation. As a result, NASA s Advanced Engineering Systems project office initiated this Radiation Storm Shelter design activity. This paper reports on the first year results of an expected 3 year Storm Shelter study effort which will mature concepts and operational scenarios that protect exploration astronauts from solar particle radiation events. Large trade space definition, candidate concept ranking, and a planned demonstration comprised the majority of FY12 activities. A system key performance parameter is minimization of the required increase in mass needed to provide a safe environment. Total system mass along with operational assessments and other defined protection system metrics provide the guiding metrics to proceed with concept developments. After a downselect to four primary methods, the concepts were analyzed for dosage severity and the amount of shielding mass necessary to bring dosage to acceptable values. Besides analytical assessments, subscale models of several concepts and one full scale concept demonstrator were created. FY12 work terminated with a plan to demonstrate test articles of two selected approaches. The process of arriving at these selections and their current envisioned implementation are presented in this paper.

  1. Study of complex molecules of biological interest with synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Prince, K.C. [Elettra-Sincrotrone Trieste, Strada Statale 14–km 163,5 in AREA Science Park, I-34149 Trieste (Italy); Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, in Area Science Park, I-34149 Trieste (Italy); Molecular Model Discovery Laboratory, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Melbourne, Victoria, 3122 (Australia); Bolognesi, P., E-mail: paola.bolognesi@cnr.it [CNR-ISM, Area della Ricerca di Roma 1, Via Salaria Km. 29,300, Monterotondo (Roma) (Italy); Feyer, V. [Elettra-Sincrotrone Trieste, Strada Statale 14–km 163,5 in AREA Science Park, I-34149 Trieste (Italy); Research Center Jülich, Peter Grünberg Institute (PGI-6), 52425 Jülich (Germany); Plekan, O. [Elettra-Sincrotrone Trieste, Strada Statale 14–km 163,5 in AREA Science Park, I-34149 Trieste (Italy); Avaldi, L. [CNR-ISM, Area della Ricerca di Roma 1, Via Salaria Km. 29,300, Monterotondo (Roma) (Italy)

    2015-10-15

    Synchrotron radiation and synchrotron based spectroscopic techniques have found important applications in the study of isolated molecular species of biological interest. In this paper, some examples of spectroscopic and dynamic studies of amino acids and small peptides, nucleobases and pharmaceuticals are reviewed. Opportunities offered by the advent of new radiation sources combined with novel methods for the production of beams of these molecules are also discussed.

  2. Study of interrelation between electromagnetic radiation and rock strength

    Science.gov (United States)

    Yavorovich, L. V.; Bespal'ko, A. A.; Fedotov, P. I.; Pomishin, E. K.

    2016-02-01

    The paper presents the study of the electromagnetic radiation of real rock samples under acoustic impact. The test samples are made of kerns from the iron ore mine with different petrophysical features and strength. The study has shown that the electromagnetic radiation parameters are related to the sample strength. However, this dependence is not observed for samples with magnetite that can be due to individual structural-textural features and quartz inclusions.

  3. Heat pipe radiation cooling evaluation: Task 2 concept studies report

    Energy Technology Data Exchange (ETDEWEB)

    Silverstein, C.C.

    1991-10-01

    This report presents the result of Task 2, Concept Studies for Heat Pipe Radiation Cooling (HPRC), which was performed for Los Alamos National Laboratory under Contract 9-XT1-U9567. Studies under a prior contract defined a reference HPRC conceptual design for hypersonic aircraft engines operating at Mach 5 and an altitude of 80,000 ft. Task 2 involves the further investigation of heat pipe radiation cooling (HPRC) systems for additional design and operating conditions.

  4. Fetal shielding combined with state of the art CT dose reduction strategies during maternal chest CT

    Energy Technology Data Exchange (ETDEWEB)

    Chatterson, Leslie C., E-mail: lch088@mail.usask.ca [Department of Diagnostic Imaging, University of Saskatchewan (Canada); Leswick, David A.; Fladeland, Derek A. [Department of Diagnostic Imaging, University of Saskatchewan (Canada); Hunt, Megan M.; Webster, Stephen [Saskatchewan Ministry of Labour Relations and Workplace Safety (Canada); Lim, Hyun [Department of Community Health and Epidemiology, College of Medicine, University of Saskatchewan (Canada)

    2014-07-15

    Purpose: Custom bismuth-antimony shields were previously shown to reduce fetal dose by 53% on an 8DR (detector row) CT scanner without dynamic adaptive section collimation (DASC), automatic tube current modulation (ATCM) or adaptive statistical iterative reconstruction (ASiR). The purpose of this study is to compare the effective maternal and average fetal organ dose reduction both with and without bismuth-antimony shields on a 64DR CT scanner using DASC, ATCM and ASiR during maternal CTPA. Materials and methods: A phantom with gravid prosthesis and a bismuth-antimony shield were used. Thermoluminescent dosimeters (TLDs) measured fetal radiation dose. The average fetal organ dose and effective maternal dose were determined using 100 kVp, scanning from the lung apices to the diaphragm utilizing DASC, ATCM and ASiR on a 64DR CT scanner with and without shielding in the first and third trimester. Isolated assessment of DASC was done via comparing a new 8DR scan without DASC to a similar scan on the 64DR with DASC. Results: Average third trimester unshielded fetal dose was reduced from 0.22 mGy ± 0.02 on the 8DR to 0.13 mGy ± 0.03 with the conservative 64DR protocol that included 30% ASiR, DASC and ATCM (42% reduction, P < 0.01). Use of a shield further reduced average third trimester fetal dose to 0.04 mGy ± 0.01 (69% reduction, P < 0.01). The average fetal organ dose reduction attributable to DASC alone was modest (6% reduction from 0.17 mGy ± 0.02 to 0.16 mGy ± 0.02, P = 0.014). First trimester fetal organ dose on the 8DR protocol was 0.07 mGy ± 0.03. This was reduced to 0.05 mGy ± 0.03 on the 64DR protocol without shielding (30% reduction, P = 0.009). Shields further reduced this dose to below accurately detectable levels. Effective maternal dose was reduced from 4.0 mSv on the 8DR to 2.5 mSv on the 64DR scanner using the conservative protocol (38% dose reduction). Conclusion: ASiR, ATCM and DASC combined significantly reduce effective maternal and fetal

  5. Electrometric sensors for neutron radiation: conceptual study

    Science.gov (United States)

    Bogolubov, E.; Koshelev, A.; Mikerov, V.; Sviridov, A.

    2012-03-01

    The paper considers main issues related to the conceptual development of neutron electrometric sensors based on charge uploading. The performance capabilities of sensors such as the detection threshold, dynamic range and sensitivity to gamma radiation were estimated for theoretically feasible designs. The designs do not contain radioactive materials, have no limitations on the fluence and the neutron flux density, can measure the time dependence of the neutron yield, can be low-sensitive to electromagnetic noise. They have a simple structure and some designs do not require the external power supply. Such sensors can be used in the control systems of nuclear reactors and subcritical assemblies, in measurements of the neutron yield of pulsed sources and in scientific investigations.

  6. Acute radiation proctitis. A clinical, histopathological and histochemical study

    Energy Technology Data Exchange (ETDEWEB)

    Hovdenak, Nils

    2004-07-01

    The aim of the study is: 1) A sequential description of the clinical course of acute radiation proctitis during pelvic RT. 2) A sequential description of the rectal mucosal histopathology during pelvic RT as a possible substrate for clinical toxicity. 3) To assess the mucosal protease activity during RT as a possible explanation of the observed tissue changes. 4) To assess the efficacy of prophylactic sucralfate in acute radiation proctitis a randomised study was initiated and carried out together with a meta-analysis of previously available data. 5) Most studies on clinical acute toxicity in pelvic RT use either the RTOG/EORTC score system or focus on diarrhoea/stool frequency. A more differentiated and sensitive recording was developed and tested to pick up symptoms escaping the commonly used scores. 6) Study the relation between histopathological findings and the clinical picture. 4 papers presenting various studies are included. The titles are: 1) Acute radiation proctitis: a sequential clinicopathologic study during pelvic radiotherapy. 2) Clinical significance of increased gelatinolytic activity in the rectal mucosa during external beam radiation therapy of prostate cancer. 3) Profiles and time course of acute radiation toxicity symptoms during conformal radiotherapy for cancer of the prostate. 4) Sucralfate does not ameliorate acute radiation proctitis. Some future prospects are discussed.

  7. Hypervelocity impact shield

    Science.gov (United States)

    Cour-Palais, Burton G. (Inventor); Crews, Jeanne Lee (Inventor)

    1991-01-01

    A hypervelocity impact shield and method for protecting a wall structure, such as a spacecraft wall, from impact with particles of debris having densities of about 2.7 g/cu cm and impact velocities up to 16 km/s are disclosed. The shield comprises a stack of ultra thin sheets of impactor disrupting material supported and arranged by support means in spaced relationship to one another and mounted to cover the wall in a position for intercepting the particles. The sheets are of a number and spacing such that the impacting particle and the resulting particulates of the impacting particle and sheet material are successively impact-shocked to a thermal state of total melt and/or vaporization to a degree as precludes perforation of the wall. The ratio of individual sheet thickness to the theoretical diameter of particles of debris which may be of spherical form is in the range of 0.03 to 0.05. The spacing between adjacent sheets is such that the debris cloud plume of liquid and vapor resulting from an impacting particle penetrating a sheet does not puncture the next adjacent sheet prior to the arrival thereat of fragment particulates of sheet material and the debris particle produced by a previous impact.

  8. New Toroid shielding design

    CERN Multimedia

    Hedberg V

    On the 15th of June 2001 the EB approved a new conceptual design for the toroid shield. In the old design, shown in the left part of the figure above, the moderator part of the shielding (JTV) was situated both in the warm and cold areas of the forward toroid. It consisted both of rings of polyethylene and hundreds of blocks of polyethylene (or an epoxy resin) inside the toroid vacuum vessel. In the new design, shown to the right in the figure above, only the rings remain inside the toroid. To compensate for the loss of moderator in the toroid, the copper plug (JTT) has been reduced in radius so that a layer of borated polyethylene can be placed around it (see figure below). The new design gives significant cost-savings and is easier to produce in the tight time schedule of the forward toroid. Since the amount of copper is reduced the weight that has to be carried by the toroid is also reduced. Outgassing into the toroid vacuum was a potential problem in the old design and this is now avoided. The main ...

  9. γ-ray shielding behaviors of some nuclear engineering materials

    Energy Technology Data Exchange (ETDEWEB)

    Mann, Kulwinder Singh [Dept. of Physics, D.A.V. College, Punjab (India)

    2017-06-15

    The essential requirement of a material to be used for engineering purposes at nuclear establishments is its ability to attenuate the most penetrating ionizing radiations, gamma (γ)-rays. Mostly, high-Z materials such as heavy concrete, lead, mercury, and their mixtures or alloys have been used in the construction of nuclear establishments and thus termed as nuclear engineering materials (NEM). The NEM are classified into two categories, namely opaque and transparent, depending on their behavior towards the visible spectrum of EM waves. The majority of NEM are opaque. By contrast, various types of glass, which are transparent to visible light, are necessary at certain places in the nuclear establishments. In the present study, γ-ray shielding behaviors (GSB) of six glass samples (transparent NEM) were evaluated and compared with some opaque NEM in a wide range of energy (15 keV–15 MeV) and optical thickness (OT). The study was performed by computing various γ-ray shielding parameters (GSP) such as the mass attenuation coefficient, equivalent atomic number, and buildup factor. A self-designed and validated computer-program, the buildup factor-tool, was used for various computations. It has been established that some glass samples show good GSB, thus can safely be used in the construction of nuclear establishments in conjunction with the opaque NEM as well.

  10. Experimental realization of open magnetic shielding

    Science.gov (United States)

    Gu, C.; Chen, S.; Pang, T.; Qu, T.-M.

    2017-05-01

    The detection of extremely low magnetic fields has various applications in the area of fundamental research, medical diagnosis, and industry. Extracting the valuable signals from noises often requires magnetic shielding facilities. We demonstrated directly from Maxwell's equations that specifically designed superconductor coils can exactly shield the magnetic field to an extremely low value. We experimentally confirmed this effect in the frequency spectrum of 0.01-10 000 Hz and improved the electromagnetic environment in a hospital, a leading hospital in magnetocardiograph study in China.

  11. The AA disappearing under concrete shielding

    CERN Multimedia

    CERN PhotoLab

    1982-01-01

    When the AA started up in July 1980, the machine stood freely in its hall, providing visitors with a view through the large window in the AA Control Room. The target area, in which the high-intensity 26 GeV/c proton beam from the PS hit the production target, was heavily shielded, not only towards the outside but also towards the AA-Hall. However, electrons and pions emanating from the target with the same momentum as the antiprotons, but much more numerous, accompanied these through the injection line into the AA ring. The pions decayed with a half-time corresponding to approximately a revolution period (540 ns), whereas the electrons lost energy through synchrotron radiation and ended up on the vacuum chamber wall. Electrons and pions produced the dominant component of the radiation level in the hall and the control room. With operation times far exceeding original expectations, the AA had to be buried under concrete shielding in order to reduce the radiation level by an order of magnitude.

  12. Upgrading the Neutron Radiography Facility in South Africa (SANRAD): Concrete Shielding Design Characteristics

    Science.gov (United States)

    de Beer, F. C.; Radebe, M. J.; Schillinger, B.; Nshimirimana, R.; Ramushu, M. A.; Modise, T.

    A common denominator of all neutron radiography (NRAD) facilities worldwide is that the perimeter of the experimental chamber of the facility is a radiation shielding structure which,in some cases, also includes flight tube and filter chamber structures. These chambers are normally both located on the beam port floor outside the biological shielding of the neutron source. The main function of the NRAD-shielding structure isto maintain a radiological safe working environment in the entire beam hall according to standards set by individual national radiological safety regulations. In addition, the shielding's integrity and capability should not allow, during NRAD operations, an increase in radiation levels in the beam port hall and thus negatively affectadjacent scientific facilities (e.g. neutron diffraction facilities).As a bonus, the shielding for the NRAD facility should also prevent radiation scattering towards the detector plane and doing so, thus increase thecapability of obtaining better quantitative results. This paper addresses Monte Carlo neutron-particletransport simulations to theoretically optimize the shielding capabilities of the biological barrierfor the SANRAD facility at the SAFARI-1 nuclear research reactor in South Africa. The experimental process to develop the shielding, based on the principles of the ANTARES facility, is described. After casting, the homogeneity distribution of these concrete mix materials is found to be near perfect and first order experimental radiation shielding characteristicsthrough film badge (TLD) exposure show acceptable values and trends in neutron- and gamma-ray attenuation.

  13. Synthesizing Graphene Production with Polymeric Injection Molding for Enhancing EMI Shielding Effectiveness of Plastics

    Science.gov (United States)

    2017-09-01

    WITH POLYMERIC INJECTION MOLDING FOR ENHANCING EMI SHIELDING EFFECTIVENESS OF PLASTICS by George K. Winstead September 2017 David C. Jenn Thesis...POLYMERIC INJECTION MOLDING FOR ENHANCING EMI SHIELDING EFFECTIVENESS OF PLASTICS 5. FUNDING NUMBERS 6. AUTHOR(S) George K. Winstead 7. PERFORMING...which graphene may be deployed to assist in suppressing radiated emissions. 14. SUBJECT TERMS graphene, injection molding, polymeric, plastics

  14. Evaluation Of Shielding Efficacy Of A Ferrite Containing Ceramic Material

    Energy Technology Data Exchange (ETDEWEB)

    Verst, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-12

    The shielding evaluation of the ferrite based Mitsuishi ceramic material has produced for several radiation sources and possible shielding sizes comparative dose attenuation measurements and simulated projections. High resolution gamma spectroscopy provided uncollided and scattered photon spectra at three energies, confirming theoretical estimates of the ceramic’s mass attenuation coefficient, μ/ρ. High level irradiation experiments were performed using Co-60, Cs-137, and Cf-252 sources to measure penetrating dose rates through steel, lead, concrete, and the provided ceramic slabs. The results were used to validate the radiation transport code MCNP6 which was then used to generate dose rate attenuation curves as a function of shielding material, thickness, and mass for photons and neutrons ranging in energy from 200 keV to 2 MeV.

  15. Carbon nano tubes -Buckypaper- radiation studies for medical physics application

    Energy Technology Data Exchange (ETDEWEB)

    Alanazi, A.; Alkhorayef, M.; Dalton, A.; Bradley, D. A. [University of Surrey, Department of Physics, College for Nuclear and Radiation Physics, Guildford, Surrey GR2 7XH (United Kingdom); Alzimami, K. [King Saud University, Department of Radiological Sciences, P. O. Box 10219, Riyadh 11433 (Saudi Arabia); Abuhadi, N., E-mail: a.alanazi@surrey.ac.uk [Jazan University, Faculty of Medical Applied Sciences, Diagnostic Radiology Department, P. O. Box 114, Jazan (Saudi Arabia)

    2015-10-15

    Radiation dosimetry underpins safe and effective clinical applications of radiation. Many materials have been used to measure the radiation dose deposited in human tissue, their radiation response requiring the application of correction factors to account for various influencing factors, including sensitivity to dose and energy dependence. In regard to the latter, account needs to be taken of difference from the effective atomic number of human tissue, soft or calcified. Graphite ion chambers and semiconductor diode detectors have been used to make measurements in phantoms but these active devices represent a clear disadvantage when considered for in vivo dosimetry. In both circumstances, dosimeters with atomic number similar to human tissue are needed. Carbon nano tubes have properties that potentially meet the demand, requiring low voltage in active devices and an atomic number similar to adipose tissue. In this study, single-wall carbon nano tubes buckypaper has been used to measure the beta particle dose deposited from a strontium-90 source, the medium displaying thermoluminescence at potentially useful sensitivity. As an example, the samples show a clear response for a dose of 2 Gy. This finding suggests that carbon nano tubes can be used as a passive dosimeter specifically for the high levels of radiation exposures used in radiation therapy. Furthermore, the finding points towards further potential applications such as for space radiation measurements, not least because the medium satisfies a demand for light but strong materials of minimal capacitance. (Author)

  16. Late Proterozoic extensional collapse in the Arabian-Nubian Shield

    NARCIS (Netherlands)

    Blasband, B.B.; White, S.H.; Brooijmans, P.; Boorder, H. de; Visser, W.

    2000-01-01

    A structural and petrological study of the Late Proterozoic rocks in the Wadi Kid area, Sinai, Egypt indicates the presence of an extensional metamorphic core complex in the northern Arabian–Nubian Shield. Gneissic domes throughout the Arabian–Nubian Shield resemble the core complex of the Wadi Kid

  17. Cerrobend shielding stents for buccal carcinoma patients

    Directory of Open Access Journals (Sweden)

    Karma Yangchen

    2016-01-01

    Full Text Available Buccal carcinoma is one of the most common oral malignant neoplasms, especially in the South Asian region. Radiotherapy, which plays a significant role in the treatment of this carcinoma, has severe adverse effects. Different types of prosthesis may be constructed to protect healthy tissues from the adverse effects of treatment and concentrate radiation in the region of the tumor mass. However, the technique for fabrication of shielding stent with Lipowitz's alloy (cerrobend/Wood's alloy has not been well documented. This article describes detailed technique for fabrication of such a stent for unilateral buccal carcinoma patients to spare the unaffected oral cavity from potential harmful effects associated with radiotherapy.

  18. Highly conductive and flexible nano-structured carbon-based polymer nanocomposites with improved electromagnetic-interference-shielding performance

    Science.gov (United States)

    Mondal, Subhadip; Ghosh, Sabyasachi; Ganguly, Sayan; Das, Poushali; Ravindren, Revathy; Sit, Subhashis; Chakraborty, Goutam; Das, Narayan Ch

    2017-10-01

    Widespread usage and development of electrical/electronic devices can create severe problems for various other devices and in our everyday lives due to harmful exposure to electromagnetic (EM) radiation. Herein, we report on the electromagnetic interference (EMI)-shielding performance of highly flexible and conductive chlorinated polyethylene (CPE)/carbon nanofiber (CNF) nanocomposites fabricated by a probe-sonication-assisted simple solution-mixing process. The dispersion of CNF nanofillers inside the CPE matrix has been studied by electron micrographs. This dispersion is reflected in the formation of continuous conductive networks at a low percolation-threshold value of 2.87 wt% and promising EMI-shielding performance of 41.5 dB for 25 wt% CNF in the X-band frequency (8.2–12.4 GHz). Such an intriguing performance mainly depends on the unique filler–filler or filler–polymer networks in CPE nanocomposites. In addition, the composite material displays a superior EMI efficiency of 47.5 dB for 2.0 mm thickness at 8.2 GHz. However, we have been encouraged by the promotion of highly flexible and lightweight CPE/CNF nanocomposite as a superior EMI shield, which can protect electronic devices against harm caused by EM radiation and offers an adaptable solution in advanced EMI-shield applications.

  19. Study on the electromagnetic radiation characteristics of discharging excimer laser system

    Science.gov (United States)

    Zhao, Duliang; Liang, Xu; Fang, Xiaodong; Wang, Qingsheng

    2016-10-01

    Excimer laser in condition of high voltage, large current and fast discharge will produce strong electromagnetic pulse radiation and electromagnetic interference on the around electrical equipment. The research on characteristics and distribution of excimer laser electromagnetic radiation could provide important basis for electromagnetic shielding and suppressing electromagnetic interference, and further improving the electromagnetic compatibility of system. Firstly, electromagnetic radiation source is analyzed according to the working principle of excimer laser. The key test points of the electromagnetic radiation, hydrogen thyratron, main discharge circuit and laser outlet, are determined by the mechanical structure and the theory of electromagnetic radiation. Secondly, characteristics of electromagnetic field were tested using a near field probe on the key positions of the vertical direction at 20, 50, and 80 cm, respectively. The main radiation frequencies and the radiation field characteristics in the near field are obtained. The experimental results show that the main radiation frequencies distribute in 47, 65, and 130 MHz for electric field and the main radiation frequencies distribute in 34, 100, and 165 MHz for magnetic field. The intensity of electromagnetic field decreases rapidly with the increase of test distance. The higher the frequency increases, the faster the amplitude attenuate. Finally, several electromagnetic interference suppression measurement methods are proposed from the perspective of electromagnetic compatibility according to the test results.

  20. Study of electromagnetic radiation produced by household equipment

    Science.gov (United States)

    Iagăr, A.; Popa, G. N.; Diniş, C. M.

    2017-05-01

    This paper presents the experimental study of electromagnetic radiation produced by different household equipment. Measurements were performed at various distances from the tested devices and in different operating modes of these, using the FA306 electromagnetic field analyzer. Also, it has been analyzed the cumulative effect of multiple sources. The experiments allowed the identification of measures to minimize the effects of exposure to artificial electromagnetic radiation produced by electrical household equipment.