Shielding performances analysis for the IFMIF test facility based on high-fidelity Monte Carlo neutronic calculations

Energy Technology Data Exchange (ETDEWEB)

Kondo, Keitaro, E-mail: kondo.keitaro@jaea.go.jp; Arbeiter, Frederik; Fischer, Ulrich; Lu, Lei; Qiu, Yuefeng; Tian, Kuo

2015-10-15

Highlights: • A detailed geometry model with pipe penetrations and gaps was prepared for the IFMIF test cell. • The neutron streaming effect due to gaps and pipes with shielding plugs was investigated. • The present analysis revealed that the streaming effect can be mitigated by some counter measures. • Occupational workers can access to the room above the test cell during operation. - Abstract: The IFMIF Test Cell (TC) design was developed and optimized in the EVEDA phase, and finally the reference TC design was proposed. The present study is devoted to further investigations of open issues on the reference TC design. In order to examine the neutron streaming effect caused by pipe penetrations and gaps around removable shielding plugs, a new geometry model for neutronic analyses has been prepared directly from engineering CAD data by utilizing the McCad conversion software. All removable shielding plugs are separately described in the model and a detailed description of pipes was incorporated into the model. The calculation result suggests that the streaming effect is mitigated if the pipe penetration is designed appropriately, while the gaps around the shielding plugs above the TC have large impact on the radiation dose in the access cell. The concept of the reference TC design has been basically validated from the neutronics point of view, although the streaming effect should be compensated by the shielding capability of the test cell cover plate so that occupational workers can access to the access cell during operation.

Shielding performances analysis for the IFMIF test facility based on high-fidelity Monte Carlo neutronic calculations

International Nuclear Information System (INIS)

Kondo, Keitaro; Arbeiter, Frederik; Fischer, Ulrich; Lu, Lei; Qiu, Yuefeng; Tian, Kuo

2015-01-01

Highlights: • A detailed geometry model with pipe penetrations and gaps was prepared for the IFMIF test cell. • The neutron streaming effect due to gaps and pipes with shielding plugs was investigated. • The present analysis revealed that the streaming effect can be mitigated by some counter measures. • Occupational workers can access to the room above the test cell during operation. - Abstract: The IFMIF Test Cell (TC) design was developed and optimized in the EVEDA phase, and finally the reference TC design was proposed. The present study is devoted to further investigations of open issues on the reference TC design. In order to examine the neutron streaming effect caused by pipe penetrations and gaps around removable shielding plugs, a new geometry model for neutronic analyses has been prepared directly from engineering CAD data by utilizing the McCad conversion software. All removable shielding plugs are separately described in the model and a detailed description of pipes was incorporated into the model. The calculation result suggests that the streaming effect is mitigated if the pipe penetration is designed appropriately, while the gaps around the shielding plugs above the TC have large impact on the radiation dose in the access cell. The concept of the reference TC design has been basically validated from the neutronics point of view, although the streaming effect should be compensated by the shielding capability of the test cell cover plate so that occupational workers can access to the access cell during operation.

Atomic site tunneling spectroscopy on high-Tc superconductors

International Nuclear Information System (INIS)

Hasegawa, T.; Nantoh, M.; Takagi, A.; Yamaguchi, W.; Ogino, M.; Kawasaki, M.

1994-01-01

Superconducting gap structures of Bi 2 Sr 2 CaCu 2 O y (BSCCO) and YBa 2 Cu 3 O y (YBCO) have been probed by scanning tunneling microscopy (STM) at cryogenic temperatures. The tunneling conductance curves observed on bulk single crystals of BSCCO and epitaxial thin films of YBCO revealed clear obershooting peaks and flat bottom regions around V=0 with quite low zero-bias conductances of ∝1%. Since the electron tunneling process in STM is essentially incoherent, the present observation is favored by the s-wave pairing mechanism. However, the conductance curves were found to be substantially smeared in comparison with the conventional spectra predicted in the BCS (isotropic s-wave) superconductors, suggesting gap anisotropy. (orig.)

600 A HTc current lead based on BSCCO 2212 rods for LHC magnets

CERN Document Server

García-Tabarés, L; Abramian, P; Toral, F; Angurel, L A; Diez, J C; Burriel, R; Natividad, E; Iturbe, R; Etxeandia, J

2000-01-01

A 600 A current lead using 2212 BSCCO bulk material is now under construction and will be soon delivered to CERN. Present paper describes the main steps of its design and fabrication, including the two main parts in which it is divided, the superconducting module with the BSCCO rods and the conventional resistive part. An important role in this design was played by previous experimental measurements on subassemblies, which are also described along the paper. (5 refs).

Strategic flat rolling of Ag/BSCCO-2223 tapes

DEFF Research Database (Denmark)

Nielsen, Morten Storgård; Bech, Jakob Ilsted; Eriksen, Morten

2002-01-01

In the process of single-step flat rolling of multifilament Ag/BSCCO-2223 wire to tape previous work has shown the optimum strategy giving maximum critical current density to be it balance between the length and width strain, so they are of equal size i.e. so, that the logarithmic strain ratio, L...

High Density Radiation Shielding Concretes for Hot Cells of 99mTc Project

International Nuclear Information System (INIS)

Sakr, K.

2006-01-01

High density concrete [more than 3.6 ton/m 3 (3.6x10 3 kg/m 3 )] was prepared to be used as a radiation shielding concrete (RSC) for hot-cells in gel technetium project at inshas to attenuate gamma radiation emitted from radioactive sources. different types of concrete were prepared by mixing local mineral aggregates mainly gravel and ilmenite . iron shots were added to the concrete mixture proportion as partial replacement of heavy aggregates to increase its density. the physical properties of prepared concrete in both plastic and hardened phases were investigated. compressive strength and radiation attenuation of gamma rays were determined. Results showed that ilmenite concrete mixed with iron shots had the highest density suitable to be use as RSC according to the chinese hot cell design requirements. Recommendations to avoid some technical problems of manufacturing radiation shielding concrete were maintained

Pinning in BSCCO above the ordinary irreversibility line

Science.gov (United States)

Indenbom, M. V.; van der Beek, C. J.; Berseth, V.; Konczykowski, M.; Motohira, N.; Berger, H.; Benoit, W.

1996-12-01

Frequency-dependent observations of magnetic flux structures are used to show that pinning plays a principal role in the whole mixed state in Bi2Sr2CaCu2O8 (BSCCO) single crystals. We speculate that the random pinning force on the moving vortices may dominate over thermal fluctuations and considerably modify the position of the vortex lattice phase transition.

High-Tc superconductor applications

International Nuclear Information System (INIS)

Anon.

1988-01-01

There has been much speculation about new products and business opportunities which high-Tc superconductors might make possible. However, with the exception of one Japanese survey, there have not been any recognized forecasts suggesting a timeframe and relative economic impact for proposed high-Tc products. The purpose of this survey is to provide definitive projections of the timetable for high-Tc product development, based on the combined forecasts of the leading U.S. superconductivity experts. The FTS panel of experts on high-Tc superconductor applications, representing both business and research, forecast the commercialization and economic impact for 28 classes of electronic, magnetic, communications, instrumentation, transportation, industrial, and power generation products. In most cases, forecasts predict the occurrence of developments within a 90% statistical confidence limit of 2-to-3 years. The report provides background information on the 28 application areas, as well as other information useful for strategic planners. The panel also forecast high-Tc research spending, markets, and international competitiveness, and provide insight into how the industry will evolve

Recent development of drastically innovative BSCCO wire (DI-BISCCO)

International Nuclear Information System (INIS)

Kikuchi, M.; Kato, T.; Ohkura, K.; Ayai, N.; Fujikami, J.; Fujino, K.; Kobayashi, S.; Ueno, E.; Yamazaki, K.; Yamade, S.; Hayashi, K.; Sato, K.; Nagai, T.; Matsui, Y.

2006-01-01

Up to this day, Ag-sheathed Bi2223 superconducting wires have been widely investigated and the long wires about 1000 m have been produced by using powder-in-tube (PIT) method on a commercial basis in the various facilities or companies. Although the wires are used for some applications such as HTS cables, magnets, motor and so on, the Bi2223 wires not only require much more improvements of the superconducting properties such as critical current, mechanical properties, but also longer and more uniform wires. Recently, the performances of Bi2223 wires have been drastically improved by using Controlled Over Pressure (CT-OP) sintering process. CT-OP process increased critical current (I c ) by more than 60% at 77 K and self field and improved the mechanical strength by more than 70%. The maximum I c was increased up to 166 A. These drastic improvements were caused by the higher density of Bi2223 filament up to almost 100% and better connectivity of the Bi2223 grains. The dense structure of the Bi2223 filaments prevents the ballooning phenomenon which is caused by the gasification of the trapped liquid nitrogen during temperature rise. Additionally, higher uniformity and higher production yield of long length wire were also achieved by exterminating defects during sintering. These high performance levels in CT-OP wires have contributed commercial level applications. We call as Drastically Innovative BSCCO (DI-BSCCO)

Microstructure and critical current density in high-Tc metal oxide superconductors

International Nuclear Information System (INIS)

Johnson, S.M.; Gusman, M.I.

1992-03-01

Superconductor powders in the U-Ba-Cu-O (YBCO) and Bi-Pb-Sr-Ca-Cu-O (BSCCO) systems were synthesized by freeze-drying. Powders were characterized, and processed into samples for evaluation of superconducting behavior. Freeze-drying is attractive because the powders have high purity, are homogeneous, have a small size and are active. YBCO powders can be sintered to high density at 890 degrees C. Many compositions, processing approaches and heat treatments were explored in an effort to understand relations between microstructure and critical density, and to improve the critical current density. Powders were also formed into sputtering targets for coating preparation at Stanford University. The highest critical current density achieved with the YBCO powders was ∼15,000 A/cm 2 at 4.2K and 0.5T using powders treated to prevent carbon contamination. The BSCCO materials with the highest critical current density, ∼30,000 A/cm 2 at the same conditions were formed by heat treating melted and quenched samples. All critical current density measurements were made by Stanford University, a subcontractor to this effort. Stanford University also prepared coatings by off-axis magnetron sputtering

Modelling and measurement of ac loss in BSCCO/Ag-tape windings

International Nuclear Information System (INIS)

Oomen, M P; Nanke, R; Leghissa, M

2003-01-01

High-temperature superconducting (HTS) transformers promise decreased weight and volume and higher efficiency. A 1 MVA HTS railway transformer was built and tested at Siemens AG. This paper deals with the prediction of ac loss in the BSCCO/Ag-tape windings. In a railway transformer the tape carries ac current in alternating field, the temperature differs from 77 K, tapes are stacked or cabled and overcurrents and higher harmonics occur. In ac-loss literature these issues are treated separately, if at all. We have developed a model that predicts the ac loss in sets of BSCCO/Ag-tape coils, and deals with the above-mentioned issues. The effect of higher harmonics on the loss in HTS tapes is considered for the first time. The paper gives a complete overview of the model equations and required input parameters. The model is validated over a wide range of the input parameters, using the measured critical current and ac loss of single tapes, single coils and sets of coils in the 1 MVA transformer. An accuracy of around 25% is achieved in all relevant cases. Presently the model is developed further, in order to describe other HTS materials and other types of applications

Study of casks shielded with heavy metal to transport highly radioactive substances

International Nuclear Information System (INIS)

Lucchesi, R.F.; Hara, D.H.S.; Martinez, L.G.; Mucsi, C.S.; Rossi, J.L.

2014-01-01

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)

Flux dynamics and magnetovoltage measurements in a macroscopic cylindrical hole drilled in BSCCO

International Nuclear Information System (INIS)

Yetis, H.; Altinkok, A.; Olutas, M.; Kilic, A.; Kilic, K.

2007-01-01

Slow transport relaxation measurements (V-t curves) and magnetovoltage measurements (V-H curves) were carried out in a polycrystalline sample of Bi 1.7 Pb 0.3 Sr 2 Ca 2 Cu 3 O x (BSCCO) with a macroscopic cylindrically drilled hole (CH). The time evolution of quenched state in V-t curves was interpreted in terms of enhancement of the superconducting order parameter and the relaxation of moving entity. Upon cycling of the external magnetic field with different sweep rates, unusual counter clockwise hysteresis effects and asymmetry in V-H curves are observed in BSCCO sample with CH, which can also be correlated to the trapping of the macroscopic flux bundles in CH

Flux dynamics and magnetovoltage measurements in a macroscopic cylindrical hole drilled in BSCCO

Science.gov (United States)

Yetiş, H.; Altinkok, A.; Olutaş, M.; Kiliç, A.; Kiliç, K.

2007-10-01

Slow transport relaxation measurements (V-t curves) and magnetovoltage measurements (V-H curves) were carried out in a polycrystalline sample of Bi1.7Pb0.3Sr2Ca2Cu3Ox (BSCCO) with a macroscopic cylindrically drilled hole (CH). The time evolution of quenched state in V-t curves was interpreted in terms of enhancement of the superconducting order parameter and the relaxation of moving entity. Upon cycling of the external magnetic field with different sweep rates, unusual counter clockwise hysteresis effects and asymmetry in V-H curves are observed in BSCCO sample with CH, which can also be correlated to the trapping of the macroscopic flux bundles in CH.

Flux dynamics and magnetovoltage measurements in a macroscopic cylindrical hole drilled in BSCCO

Energy Technology Data Exchange (ETDEWEB)

Yetis, H.; Altinkok, A.; Olutas, M. [Abant Izzet Baysal University, Department of Physics, Turgut Gulez Research Laboratory, 14280 Bolu (Turkey); Kilic, A. [Abant Izzet Baysal University, Department of Physics, Turgut Gulez Research Laboratory, 14280 Bolu (Turkey)], E-mail: kilic_a@ibu.edu.tr; Kilic, K. [Abant Izzet Baysal University, Department of Physics, Turgut Gulez Research Laboratory, 14280 Bolu (Turkey)

2007-10-01

Slow transport relaxation measurements (V-t curves) and magnetovoltage measurements (V-H curves) were carried out in a polycrystalline sample of Bi{sub 1.7}Pb{sub 0.3}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (BSCCO) with a macroscopic cylindrically drilled hole (CH). The time evolution of quenched state in V-t curves was interpreted in terms of enhancement of the superconducting order parameter and the relaxation of moving entity. Upon cycling of the external magnetic field with different sweep rates, unusual counter clockwise hysteresis effects and asymmetry in V-H curves are observed in BSCCO sample with CH, which can also be correlated to the trapping of the macroscopic flux bundles in CH.

Observation of an hexatic vortex glass in flux lattices of the high-Tc superconductor Bi2.1Sr1.9Ca0.9Cu2O8+δ

International Nuclear Information System (INIS)

Bishop, D.J.; Gammel, P.L.; Murray, C.A.; Mitzi, D.B.; Kapitulnik, A.

1991-01-01

We report observation of hexatic order in Abrikosov flus lattices in very clean crystals of the high-Tc superconductor Bi 2.1 Sr 1.9 Ca 0.9 Cu 2 O 8+δ (BSCCO). Our experiments consist of in situ magnetic decoration of the flux lattice at 4.2 K. Analysis of the decoration images shows that the positional order decays exponentially with a correlation length of a few lattice constants while the orientational order persists for hundreds of lattice constants and decays algebraically with an exponent η 6 =0.6±0.01. Our results confirm recent theoretical speculation that the positional order should be far more sensitive to disorder than the orientational order and that the low-temperature ordered phase of the flux lines in these systems might be an hexatic glass. (orig.)

Observation of an hexatic vortex glass in flux lattices of the high- Tc superconductor Bi 2.1Sr 1.9Ca 0.9Cu 2O 8+δ

Science.gov (United States)

Bishop, D. J.; Gammel, P. L.; Murray, C. A.; Mitzi, D. B.; Kapitulnik, A.

1991-02-01

We report observation of hexatic order in Abrikosov flux lattices in very clean crystals of the high- Tc superconductor Bi 2.1Sr 1.9Ca 0.9Cu 2O 8+δ (BSCCO). Our experiments consist of in situ magnetic decoration of the flux lattice at 4.2 K. Analysis of the decoration images shows that the positional order decays exponentially with a correlation length of a few lattice constants while the orientational order persists for hundreds of lattice constants and decays algebraically with an exponent η 6 = 0.6 ± 0.01. Our results confirm recent theoretical speculation that the positional order should be far more sensitive to disorder than the orientational order and that the low-temperature ordered phase of the flux lines in these systems might be an hexatic glass.

Observation of an hexatic vortex glass in flux lattices of the high Tc superconductor Bi2.1Sr1.9Ca0.9Cu2O8+δ

Science.gov (United States)

Bishop, D. J.; Gammel, P. L.; Murray, C. A.; Mitzi, D. B.; Kapitulnik, A.

1990-10-01

We report observation of hexatic order in Abrikosov flux lattices in very clean crystals of the high Tc superconductor Bi2.1Sr1.9Ca0.9Cu2O8+δ (BSCCO). Our experiments consist of in situ magnetic decoration of the flux lattice at 4.2 K. Analysis of the decoration images shows that the positional order decays exponentially with a correlation length of a few lattice constants while the orientational order persists for hundreds of lattice constants and decays algebraically with an exponent η6=0.06±0.01. Our results confirm recent theoretical speculation that the positional order should be far more sensitive to disorder than the orientational order and that the low temperature ordered phase of the flux lines in these systems might be an hexatic glass.

New possibility of magnetic ripple shielding for specific heat measurements in hybrid magnets

NARCIS (Netherlands)

Tarnawski, Z.; Meulen, der, H. van; Franse, J.J.M.; Kadowaki, K.; Veenhuizen, P.A.; Klaasse, J.

1988-01-01

A test of the new high Tc superconducting materials for magnetic ripple shielding has been carried out. It was found that magnetic ripples of 0.0009 T (peak-to-peak) in the frequency range below 20 kHz can be completely shielded in high static fields by a 2 mm thick Y-Ba-Cu-O screen.

The Goettingen high-Tc superconductivity research pool: the effects of structure and structural defects on the performance of high-Tc superconductors. Final reports

International Nuclear Information System (INIS)

1992-02-01

The compilation presents the final reports prepared by the various teams of the Goettingen research pool for high-Tc superconductivity. The reports are entitled: Structure and phase transition in high-Tc superconductors (Krebs/Freyhardt). Preparation and critical properties of high-Tc superconductors (Freyhardt/Heinemann/Zimmermann). EMC measurements in high-Tc superconductors (Bormann/Noelting). Phase analysis of the various phases observed in the preparation of high-Tc superconductors (Faupel/Hehenkamp). Positron annihilation in high-Tc superconductors (Hehenkamp). Preparation and characterization of thin films consisting of superconducting oxide ceramics (v. Minnigerode/Samwer). High-Tc superconductivity in monocrystals (Winzer/Beuermann). Microwave conductivity in high-Tc superconductors (Helberg). High-resolution structural analyses in high-Tc superconductors (Kupcik/Bente). Synthesis, structural analyses and spectroscopy of high-Tc superconductors (Bente). Synthesis, monocrystal growing, crystal structure of high-Tc superconductors (Schwarzmann). Ion-beam-aided studies in high-Tc superconductors (Uhrmacher). (orig./MM) [de

Quantitative analysis of the effects of strain-state on the microstructure and Jc of BSCCO tapes

International Nuclear Information System (INIS)

Blumenthal, W.R.; Zhu, Y.T.; Sebring, R.J.; Lowe, T.C.; Asaro, R.J.

1996-01-01

After considerable optimization efforts, conventional thermomechanical processing of long, high temperature superconductors has not produced critical current densities (J c ) adequate for most liquid nitrogen temperature applications. New approaches are needed to improve the J c of superconducting tape produced by co-deforming a ductile silver sheath containing the superconducting oxide using the powder-in-tube process. This study investigates improvements in J c generated by modifying the strain-state during rolling of silver-sheathed Bi 2 Sr 2 Ca 2 Cu 3 O 10+x (BSCCO-2223) tape using quantitative image analysis of the different phases. Pure compression and combined compression-shear loading was achieved by embedding BSCCO-2223 tapes at different locations within thick steel blocks. High hydrostatic compressive stress was imposed by confining the tape width. Tapes deformed with combined shear-compression exhibited measurably higher J c values than tapes subjected to pure compression, but their microstructures showed little difference in the amount of nonconducting (including porosity) phase content. However, constraining the tape width resulted in the most significant increase in J c which corresponded to a much lower porosity and nonconducting phase volume in the oxide near the tape edge

Finite-element analysis and comparison of the AC loss performance of BSCCO and YBCO conductors

International Nuclear Information System (INIS)

Stavrev, Svetlomir; Grilli, Francesco; Dutoit, Bertrand; Ashworth, Stephen

2006-01-01

The AC loss performance of two BSCCO and two YBCO conductors of different geometry, characterized by the same self-field critical current of 150 A, is analysed and compared quantitatively. The comparison is made using the finite-element method with a nonlinear B-dependent E-J relation. A new shell-region model is utilised for the simulations of thin YBCO strips. Different AC working conditions are simulated: self-field, applied external field, and combined transport current and external perpendicular field application. Magnetic field and current density profiles are investigated in order to illustrate the reasons for the loss difference in the conductors. Depending on the application, the advantages of using BSCCO or YBCO conductors with specific geometry are outlined

Progress in the development of BSCCO-2212 superconductors

International Nuclear Information System (INIS)

Walker, M.S.; Dietderich, D.R.

1992-11-01

BSCCO-2212 powders were uniformly dip coated on silver ribbons of 1 meter lengths. Short sample sandwiches of various combinations of silver and the dip coated ribbon were reacted to form possible conductor geometries for characterization and testing. Optical and Scanning Electron Microscope (SEM) examination of surfaces and cross sections showed good but still not ideal microstructure. Representative critical current densities at 6 T and 4.2 K ranged from 8 x 10 3 A/cm 2 for sandwich samples to 2 x 10 4 A/cm 2 for open-faced samples

Fault current limiter-predominantly resistive behavior of a BSCCO shielded-core reactor

International Nuclear Information System (INIS)

Ennis, M. G.; Tobin, T. J.; Cha, Y. S.; Hull, J. R.

2000-01-01

Tests were conducted to determine the electrical and magnetic characteristics of a superconductor shielded core reactor (SSCR). The results show that a closed-core SSCR is predominantly a resistive device and an open-core SSCR is a hybrid resistive/inductive device. The open-core SSCR appears to dissipate less than the closed-core SSCR. However, the impedance of the open-core SSCR is less than that of the closed-core SSCR. Magnetic and thermal diffusion are believed to be the mechanism that facilitates the penetration of the superconductor tube under fault conditions

Enhancement in the high-T{sub c} phase of BSCCO superconductors by Nb addition

Energy Technology Data Exchange (ETDEWEB)

Soezeri, Hueseyin [TUBITAK-UME, National Metrology Institute, PO Box 54 TR-41470, Gebze Kocaeli (Turkey); Ghazanfari, Nader [Middle East Technical University, Physics Department, 06531 Ankara (Turkey); Oezkan, Huesnue [Middle East Technical University, Physics Department, 06531 Ankara (Turkey); Kilic, Ahmet [Middle East Technical University, Physics Department, 06531 Ankara (Turkey)

2007-06-15

Pure and Nb{sub 2}O{sub 5} added Bi{sub 1.6}Pb{sub 0.4}Nb{sub x}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub {delta}} superconductors (x varies up to 0.30) were synthesized by the solid state reaction method. Structural and superconducting properties of the samples were investigated. The fraction of the high-T{sub c} phase (2223) increases with Nb addition up to x = 0.10, for which a nearly single 2223 phase was obtained. The critical temperature of the samples increases from 96 to 104 K with doping up to x = 0.20 and a further increase in Nb decreases the T{sub c} sharply. Similarly, there is a considerable enhancement in the critical current density (j{sub c}) of the samples in the same doping range. Both AC susceptibility and transport measurements showed that the optimum Nb concentration is x = 0.20. The out-of-phase component of the AC susceptibility measurements showed that inter-grain coupling was enhanced up to the same doping level. Nb additions above x = 0.30 decrease the fraction of the high-T{sub c} phase and degrade the superconducting properties. Present measurements indicate that x = 0.20 is the optimum Nb concentration in the BSCCO superconductor to enhance phase purity, inter-grain coupling and superconducting parameters (T{sub c} and j{sub c})

Shielding technology for high energy radiation production facility

International Nuclear Information System (INIS)

Lee, Byung Chul; Kim, Heon Il

2004-06-01

In order to develop shielding technology for high energy radiation production facility, references and data for high energy neutron shielding are searched and collected, and calculations to obtain the characteristics of neutron shield materials are performed. For the evaluation of characteristics of neutron shield material, it is chosen not only general shield materials such as concrete, polyethylene, etc., but also KAERI developed neutron shields of High Density PolyEthylene (HDPE) mixed with boron compound (B 2 O 3 , H 2 BO 3 , Borax). Neutron attenuation coefficients for these materials are obtained for later use in shielding design. The effect of source shape and source angular distribution on the shielding characteristics for several shield materials is examined. This effect can contribute to create shielding concept in case of no detail source information. It is also evaluated the effect of the arrangement of shield materials using current shield materials. With these results, conceptual shielding design for PET cyclotron is performed. The shielding composite using HDPE and concrete is selected to meet the target dose rate outside the composite, and the dose evaluation is performed by configuring the facility room conceptually. From the result, the proper shield configuration for this PET cyclotron is proposed

Frequency dependence of magnetic shielding performance of HTS plates in mixed states

International Nuclear Information System (INIS)

Kamitani, Atsushi; Yokono, Takafumi; Yokono, Takafumi

2000-01-01

The magnetic shielding performance of the high-Tc superconducting (HTS) plate is investigated numerically. The behavior of the shielding current density in the HTS plate is expressed as the integral-differential equation with a normal component of the current vector potential as a dependent variable. The numerical code for solving the equation has been developed by using the combination of the Newton-Raphson method and the successive substitution method and, by use of the code, damping coefficients and shielding factors are evaluated for the various values of the frequency ω. The results of computations show that the HTS plate has a possibility of shielding the high-frequency magnetic field with ω > or approx. 1 kHz. (author)

Frequency dependence of magnetic shielding performance of HTS plates in mixed states

Energy Technology Data Exchange (ETDEWEB)

Kamitani, Atsushi; Yokono, Takafumi [Yamagata Univ., Yonezawa (Japan). Faculty of Engineering; Yokono, Takafumi [Tsukuba Univ., Ibaraki (Japan). Inst. of Information Sciences and Electronics

2000-06-01

The magnetic shielding performance of the high-Tc superconducting (HTS) plate is investigated numerically. The behavior of the shielding current density in the HTS plate is expressed as the integral-differential equation with a normal component of the current vector potential as a dependent variable. The numerical code for solving the equation has been developed by using the combination of the Newton-Raphson method and the successive substitution method and, by use of the code, damping coefficients and shielding factors are evaluated for the various values of the frequency {omega}. The results of computations show that the HTS plate has a possibility of shielding the high-frequency magnetic field with {omega} > or approx. 1 kHz. (author)

New superconductors from granular to high T$_{c}$

CERN Document Server

Deutscher, Guy

2018-01-01

How new are the high Tc superconductors, as compared to the conventional low Tc ones? In what sense are these oxides different from regular metals in their normal state? How different is the mechanism for high Tc superconductivity from the well-known electron-phonon interaction that explains so well superconductivity in metals and alloys? What are the implications of the new features of the high Tc oxides for their practical applications? This interesting book aims to provide some answers to those questions, drawing particularly on similarities between the high Tc oxides and granular superconductors, which also present a short coherence length, a small superfluid density and an inhomogeneous structure.

New superconductors from granular to high T$_{c}$

CERN Document Server

Deutscher, Guy

2006-01-01

How new are the high Tc superconductors, as compared to the conventional low Tc ones? In what sense are these oxides different from regular metals in their normal state? How different is the mechanism for high Tc superconductivity from the well-known electron-phonon interaction that explains so well superconductivity in metals and alloys? What are the implications of the new features of the high Tc oxides for their practical applications? This book aims to give some answers to those questions, drawing particularly on similarities between the high Tc oxides and granular superconductors, which also present a maximum of their critical temperature near the metal-insulator transition.

Pressure and high-Tc superconductivity in sulfur hydrides.

Science.gov (United States)

Gor'kov, Lev P; Kresin, Vladimir Z

2016-05-11

The paper discusses fundamentals of record-TC superconductivity discovered under high pressure in sulfur hydride. The rapid increase of TC with pressure in the vicinity of Pcr ≈ 123GPa is interpreted as the fingerprint of a first-order structural transition. Based on the cubic symmetry of the high-TC phase, it is argued that the lower-TC phase has a different periodicity, possibly related to an instability with a commensurate structural vector. In addition to the acoustic branches, the phonon spectrum of H3S contains hydrogen modes with much higher frequencies. Because of the complex spectrum, usual methods of calculating TC are here inapplicable. A modified approach is formulated and shown to provide realistic values for TC and to determine the relative contributions of optical and acoustic branches. The isotope effect (change of TC upon Deuterium for Hydrogen substitution) originates from high frequency phonons and differs in the two phases. The decrease of TC following its maximum in the high-TC phase is a sign of intermixing with pairing at hole-like pockets which arise in the energy spectrum of the cubic phase at the structural transition. On-pockets pairing leads to the appearance of a second gap and is remarkable for its non-adiabatic regime: hydrogen mode frequencies are comparable to the Fermi energy.

Highly heat removing radiation shielding material

International Nuclear Information System (INIS)

Asano, Norio; Hozumi, Masahiro.

1990-01-01

Organic materials, inorganic materials or metals having excellent radiation shielding performance are impregnated into expanded metal materials, such as Al, Cu or Mg, having high heat conductivity. Further, the porosity of the expanded metals and combination of the expanded metals and the materials to be impregnated are changed depending on the purpose. Further, a plurality of shielding materials are impregnated into the expanded metal of the same kind, to constitute shielding materials. In such shielding materials, impregnated materials provide shielding performance against radiation rays such as neutrons and gamma rays, the expanded metals provide heat removing performance respectively and they act as shielding materials having heat removing performance as a whole. Accordingly, problems of non-informity and discontinuity in the prior art can be dissolved be provide materials having flexibility in view of fabrication work. (T.M.)

Observation of an hexatic vortex glass in flux lattices of the high-Tc superconductor Bi sub 2. 1 Sr sub 1. 9 Ca sub 0. 9 Cu sub 2 O sub 8+. delta

Energy Technology Data Exchange (ETDEWEB)

Bishop, D J; Gammel, P L; Murray, C A [AT and T Bell Labs., Murray Hill, NJ (USA); Mitzi, D B; Kapitulnik, A [Stanford Univ., CA (USA)

1991-02-01

We report observation of hexatic order in Abrikosov flus lattices in very clean crystals of the high-Tc superconductor Bi{sub 2.1}Sr{sub 1.9}Ca{sub 0.9}Cu{sub 2}O{sub 8+{delta}} (BSCCO). Our experiments consist of in situ magnetic decoration of the flux lattice at 4.2 K. Analysis of the decoration images shows that the positional order decays exponentially with a correlation length of a few lattice constants while the orientational order persists for hundreds of lattice constants and decays algebraically with an exponent {eta}{sub 6}=0.6{+-}0.01. Our results confirm recent theoretical speculation that the positional order should be far more sensitive to disorder than the orientational order and that the low-temperature ordered phase of the flux lines in these systems might be an hexatic glass. (orig.).

Detection of nuclear magnetic resonance in the microtesla range using a high Tc dc-SQUID

Science.gov (United States)

Wang, Ning; Jin, Yirong; Li, Shao; Ren, Yufeng; Tian, Ye; Chen, Yingfei; Li, Jie; Chen, Genghua; Zheng, Dongning

2012-12-01

We have detected the ultra-low field nuclear magnetic resonance signal from water samples using a high-Tc dc-SQUID sensor. The measurements were carried out in a homemade magnetically shielded room. Resonance spectra of 1H from tap water and other substance samples were obtained in the field range from 7-110μT corresponding to resonance frequency 300-4.68kHz. Two kind of experimental systems were built, the first one is a directly coupled system, its signal to noise ratio in a single-shot measurement is around 4 for about 15 ml water. The second one used a Cu coil to transfer the flux to the SQUID sensor. Signal to noise ratio was improved to about 20 in a single-shot measurement for 5ml water, which benefits from the improvement of coupling efficiency. The effect of residual gradient in the magnetically shielded room was also investigated. J-coupling of 2,2,2-Trifluoroethyl alcohol was measured, the peaks are consistent with high field results.

Magnetic levitation systems using a high-Tc superconducting bulk magnet

Energy Technology Data Exchange (ETDEWEB)

Ohsaki, Hiroyuki [Dept. of Electrical Engineering, Univ. of Tokyo (Japan); Kitahara, Hirotaka [Dept. of Electrical Engineering, Univ. of Tokyo (Japan); Masada, Eisuke [Dept. of Electrical Engineering, Univ. of Tokyo (Japan)

1996-12-31

Recent development of high-performance high-Tc bulk superconductors is making their application for electromagnetic force use feasible. We have studied electromagnetic levitation systems using high-Tc bulk superconducting material. In this paper, after an overview of superconducting magnetic levitation systems, with an emphasis on high-Tc bulk superconductor applications, experimental results of a high-Tc bulk EMS levitation and FEM analysis results of magnetic gradient levitation using bulk superconductor are described. Problems to be solved for their application are also discussed. (orig.)

Josephson plasma resonance in superconducting multilayers

DEFF Research Database (Denmark)

Pedersen, Niels Falsig

1999-01-01

We derive an analytical solution for the josephson plasma resonance of superconducting multilayers. This analytical solution is derived mainly for low T-c systems with magnetic coupling between the superconducting layers, but many features of our results are more general, and thus an application...... to the recently derived plasma resonance phenomena for high T-c superconductors of the BSCCO type is discussed....

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.

Evaluation of radiation shielding rate of lead aprons in nuclear medicine

International Nuclear Information System (INIS)

Han, Sang Hyun; Han, Beom Heui; Lee, Sang Ho; Hong, Dong Heui; Kim, Gi Jin

2017-01-01

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 "9"9"mTc, "1"8F, "1"3"1I, "1"2"3I, and "2"0"1Tl, 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 "9"9"mTc 31.59%, "2"0"1Tl 68.42%, and "1"2"3I 76.63%. When using an apron, the shielding rate of "1"3'1I actually resulted in average dose rate increase of 33.72%, and "1"8F 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 "1"2"3I, "2"0"1Tl, "9"9"mTc, "1"8F, "1"3"1I. 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

Electronic properties of high-Tc superconductors. The normal and the superconducting state of high-Tc materials. Proceedings

International Nuclear Information System (INIS)

Kuzmany, H.; Mehring, M.; Fink, J.

1993-01-01

The International Winter School on Electronic Properties of High-Temperature Superconductors, held between March 7-14, 1992, in Kirchberg, (Tyrol) Austria, was the sixth in a series of meetings to be held at this venue. Four of the earlier meetings were dedicated to issues in the field of conducting polymers, while the winter school held in 1990 was devoted to the new discipline of high-Tc superconductivity. This year's meeting constituted a forum not only for the large number of scientists engaged in high-Tc research, but also for those involved in the new and exciting field of fullerenes. Many of the issues raised during the earlier winter schools on conducting polymers, and the last one on high-Tc superconductivity, have taken on a new significance in the light of the discovery of superconducting C 60 materials. The Kirchberg meetings are organized in the style of a school where experienced scientists from universities, research laboratories and industry have the opportunity to discuss their most recent results, and where students and young scientists can learn about the present status of research and applications from some of the most eminent workers in their field. In common with the previous winter school on high-Tc superconductors, the present one focused on the electronic properties of the cuprate superconductors. In addition, consideration was given to related compounds which are relevant to the understanding of the electronic structure of the cuprates in the normal state, to other oxide superconductors and to fulleride superconductors. Contributions dealing with their preparation, transport and thermal properties, high-energy spectroscopies, nuclear magnetic resonance, inelastic neutron scattering, and optical spectroscopy are presented in this volume. The theory of the normal and superconducting states also occupies a central position. (orig.)

Thermoelectric coefficient L(T) of polycrystalline silver doped BSCCO samples

International Nuclear Information System (INIS)

Rodriguez, J.E.; Marino, A.

1998-01-01

We present a study of the thermoelectric coefficient L(T) of polycrystalline silver doped BSCCO samples. The quantity L(T) relates the thermoelectric coefficient S(T) with the electrical conductivity σ (T) and gives an indication of the influence of the order parameter fluctuations (OPF) on S(T) in the mean field region (Mfr). The results of L(T) indicate that the critical behavior of S(T) above the superconducting transition is not only driven by σ (T). These results suggest that in the Mfr, L(T) is affected by thermodynamic fluctuations of the superconducting order parameter (OPF). The OPF effects show a two-dimensional (2D) character in the entire Mfr. (Author)

Highly Efficient and Reliable Transparent Electromagnetic Interference Shielding Film.

Science.gov (United States)

Jia, Li-Chuan; Yan, Ding-Xiang; Liu, Xiaofeng; Ma, Rujun; Wu, Hong-Yuan; Li, Zhong-Ming

2018-04-11

Electromagnetic protection in optoelectronic instruments such as optical windows and electronic displays is challenging because of the essential requirements of a high optical transmittance and an electromagnetic interference (EMI) shielding effectiveness (SE). Herein, we demonstrate the creation of an efficient transparent EMI shielding film that is composed of calcium alginate (CA), silver nanowires (AgNWs), and polyurethane (PU), via a facile and low-cost Mayer-rod coating method. The CA/AgNW/PU film with a high optical transmittance of 92% achieves an EMI SE of 20.7 dB, which meets the requirements for commercial shielding applications. A superior EMI SE of 31.3 dB could be achieved, whereas the transparent film still maintains a transmittance of 81%. The integrated efficient EMI SE and high transmittance are superior to those of most previously reported transparent EMI shielding materials. Moreover, our transparent films exhibit a highly reliable shielding ability in a complex service environment, with 98 and 96% EMI SE retentions even after 30 min of ultrasound treatment and 5000 bending cycles (1.5 mm radius), respectively. The comprehensive performance that is associated with the facile fabrication strategy imparts the CA/AgNW/PU film with great potential as an optimized EMI shielding material in emerging optoelectronic devices, such as flexible solar cells, displays, and touch panels.

Rugged Low-Resistance Contacts To High-Tc Superconductors

Science.gov (United States)

Caton, Randall; Selim, Raouf; Byvik, Charles E.; Buoncristiani, A. Martin

1992-01-01

Newly developed technique involving use of gold makes possible to fabricate low-resistance contacts with rugged connections to high-Tc superconductors. Gold diffused into specimen of superconducting material by melting gold beads onto surface of specimen, making strong mechanical contacts. Shear strength of gold bead contacts greater than epoxy or silver paste. Practical use in high-current-carrying applications of new high-Tc materials, including superconducting magnets, long-wavelength sensors, electrical ground planes at low temperatures, and efficient transmission of power.

Radiation Attenuation and Stability of ClearView Radiation Shielding TM-A Transparent Liquid High Radiation Shield.

Science.gov (United States)

Bakshi, Jayeesh

2018-04-01

Radiation exposure is a limiting factor to work in sensitive environments seen in nuclear power and test reactors, medical isotope production facilities, spent fuel handling, etc. The established choice for high radiation shielding is lead (Pb), which is toxic, heavy, and abidance by RoHS. Concrete, leaded (Pb) bricks are used as construction materials in nuclear facilities, vaults, and hot cells for radioisotope production. Existing transparent shielding such as leaded glass provides minimal shielding attenuation in radiotherapy procedures, which in some cases is not sufficient. To make working in radioactive environments more practicable while resolving the lead (Pb) issue, a transparent, lightweight, liquid, and lead-free high radiation shield-ClearView Radiation Shielding-(Radium Incorporated, 463 Dinwiddie Ave, Waynesboro, VA). was developed. This paper presents the motivation for developing ClearView, characterization of certain aspects of its use and performance, and its specific attenuation testing. Gamma attenuation testing was done using a 1.11 × 10 Bq Co source and ANSI/HPS-N 13.11 standard. Transparency with increasing thickness, time stability of liquid state, measurements of physical properties, and performance in freezing temperatures are reported. This paper also presents a comparison of ClearView with existing radiation shields. Excerpts from LaSalle nuclear power plant are included, giving additional validation. Results demonstrated and strengthened the expected performance of ClearView as a radiation shield. Due to the proprietary nature of the work, some information is withheld.

Mechanism of Pb and Sb role on the 2223 phase of BSCCO system superconductor

Energy Technology Data Exchange (ETDEWEB)

Sukirman, E; Sulisworo, P; Prasuad, W; Wuryanto, [Material Science Research Centre, National Atomic Energy Agency, Kawasan Puspiptek Serpong Tangerang (Indonesia)

1998-10-01

The mechanism of Pb and Sb role on the 2223 phase of Bi-Sr-Ca-Cu-O (BSCCO) system superconductor has been investigated. The 2223 phase samples without doping and with doping: Pb, and Sb have been synthesized by solid state reaction method. The samples characterization have been carried out through a susceptibility-, resistivity-, neutron diffraction profile-, and microstructure measurements. Crystal structure of the samples have been analyzed using RIETAN software. The analysis results show that relative content of the 2223 phase increase from 28% in the non-doped sample (TDP) to 75% in Pb-doped (DPB) and 44% in Sb-doped (DSB) samples. When, Pb, or Sb enter into the 2223 phase crystal system, then the oxygen atoms on SrO layers shift toward the copper atoms position on Cu(2)O{sub 2} layers as far as 0.1(1) and 0.1(1) A in DPB, and DSB, respectively. BiO layers shift away from SrO layers as far as 0.3(1) and 0.1(1) A in DPB, and DSB, respectively. The critical current density Jc increase from 3 A/cm{sup 2} in TDP to 210 and 35 A/cm{sup 2} in DPB, and DSB, respectively. The onset point of Tc also increase from 99 K in TDP to 103 and 107 K in DPB and DSB, respectively. It is concluded that the enhancement of the 2223 phase, Jc and onset point are due to improvement on the structure stability, improvement on the connection between unit-cells, and shortening the apical oxygen-Cu chains, respectively. (author)

Beta induced Bremsstrahlung dose rate in concrete shielding

International Nuclear Information System (INIS)

Manjunatha, H.C.

2013-01-01

Dosimetric study of beta-induced Bremsstrahlung in concrete is importance in the field of radiation protection. The efficiency, intensity and dose rate of beta induced Bremsstrahlung by 113 pure beta nuclides in concrete shielding is computed. The Bremsstrahlung dosimetric parameters such as the efficiency (yield), Intensity and dose rate of Bremsstrahlung are low for 199 Au and high for 104 Tc in concrete. The efficiency, Intensity and dose rate of Bremsstrahlung increases with maximum energy of beta nuclide (Emax) and modified atomic number (Zmod) of the target. The estimated Bremsstrahlung efficiency, Intensity and dose rate are useful in the calculations photon track-length distributions. These parameters are useful to determine the quality and quantity of the radiation (known as the source term). Precise estimation of this source term is very important in planning of radiation shielding. (author)

Study on Basic Characteristics for the Development of Radiation Shielding High-Weight Concrete

Energy Technology Data Exchange (ETDEWEB)

Mun, Young Bum; Lee, Jea Hyung; Choi, Hyun Kook [Sungshin Cement CO., Sejong (Korea, Republic of); Oh, Jeong Hwan; Choi, Soo Seok [Jeju National University, Jeju (Korea, Republic of)

2016-05-15

It is planned to build a power plant more than 6 units. Although the demand of a nuclear power plant is going to increase, the attention for radiation shielding is relatively in a low level. Concrete is one of the excellent and widely used shielding materials. Since the radiation shielding of a given material is proportional to density and thickness, a high-weight concrete with high-weight aggregate which is higher than normal concrete is used for radiation shielding. However, there are a few studies and references about radiation shielding concrete. Therefore, it is required to find a high-weight aggregate. The purpose of this paper is the development of a highweight concrete to improve radiation shielding capability. The radiation shielding rate of high-weight concrete is higher than that of reference concrete. It is confirmed that the density of aggregate and the unit weight of concreate is proportional to the radiation shielding rate. In addition, the chemical composition of aggregate has also has an important effect on γ-ray shielding. Therefore, high weight aggregates of higher density are essentially required to improve radiation shielding capability. The compressive strength of a high weight concrete is better than that of reference concrete. Slump and air contents, however, are slightly increased with by-product aggregates.

Minimizing exposure in nuclear medicine through optimum use of shielding devices

International Nuclear Information System (INIS)

Rutherford, B.L.; King, S.H.; Erdman, M.C.; Miller, K.L.

1991-01-01

Exposure to radiation from nuclear medicine nuclides can be minimized through the use of various shielding devices. This paper reviews the dose reductions achieved through use of various syringe shields, lead aprons, leaded gloves, and several types of eyeglass lenses for 67 Ga, 99m Tc, 131 I and 201 Tl. The authors have found that combination of devices can best provide for minimizing doses

Remote sampling and analysis of highly radioactive samples in shielded boxes

International Nuclear Information System (INIS)

Kirpikov, D.A.; Miroshnichenko, I.V.; Pykhteev, O.Yu.

2010-01-01

The sampling procedure used for highly radioactive coolant water is associated with high risk of personnel irradiation and uncontrolled radioactive contamination. Remote sample manipulation with provision for proper radiation shielding is intended for safety enhancement of the sampling procedure. The sampling lines are located in an isolated compartment, a shielded box. Various equipment which enables remote or automatic sample manipulation is used for this purpose. The main issues of development of the shielded box equipment intended for a wider ranger of remote chemical analyses and manipulation techniques for highly radioactive water samples are considered in the paper. There were three principal directions of work: Transfer of chemical analysis performed in the laboratory inside the shielded box; Prevalence of computer-aided and remote techniques of highly radioactive sample manipulation inside the shielded box; and, Increase in control over sampling and determination of thermal-hydraulic parameters of the coolant water in the sampling lines. The developed equipment and solutions enable remote chemical analysis in the restricted volume of the shielded box by using ion-chromatographic, amperometrical, fluorimetric, flow injection, phototurbidimetric, conductometric and potentiometric methods. Extent of control performed in the shielded box is determined taking into account the requirements of the regulatory documents as well as feasibility and cost of the technical adaptation of various methods to the shielded box conditions. The work resulted in highly precise determination of more than 15 indexes of the coolant water quality performed in on-line mode in the shielded box. It averages to 80% of the total extent of control performed at the prototype reactor plants. The novel solutions for highly radioactive sample handling are implemented in the shielded box (for example, packaging, sample transportation to the laboratory, volume measurement). The shielded box is

Preparation and characterization of thick BSCCO 2223 films

International Nuclear Information System (INIS)

Ciancio, G; Avila, A; Malachevsky, M.T; Ovidio, C.A

2002-01-01

Among the most widespread applications for critical high-temperature ceramic superconductors are for silver veined tapes, with the superconductor in the middle. These tapes are prepared by the powder- in - tube method. To attain high densities of critical current, the ceramic material must have a certain texture, with the grains oriented with the c axis perpendicular to the direction in which the current circulates. In the system that was studied, the degree of orientation increases as the distance to the vein decreases, with the maximum being in the silver-ceramic inter-phase. Superconductor tapes become inconvenient when defining the ceramic, especially because of the orientation of their plates as a function of the distance to the silver. Although the silver can be dissolved by a chemical attack in order to uncover the ceramic, greater precaution is needed while manipulating the superconductor and obtaining representative data. The behavior of thick films of the compound BSCCO 2223, deposited on silver sheets, forming silver-ceramic composites, was studied. These sheets simulate the silver-ceramic inter-phase and the distribution of the grains towards the center in a thick tape. After the samples were prepared, the phases that were present were characterized by x-ray diffraction and the resulting microstructure was analyzed with a SEM (Scanning Electron Microscope). Its mechanical properties were evaluated, following the formation and propagation of cracks in real time using four point flexion microassays inside the SEM chamber, as well as generating tension-deformation curves. The method of preparation of the thick films is discussed and its influence on the results obtained with the different characterizations (cw)

Magnetically-related properties of bismuth containing high Tc superconductors

Science.gov (United States)

Vezzoli, Gary C.; Chen, M. F.; Craver, F.; Safari, A.; Moon, B. M.; Lalevic, B.; Burke, Terence; Shoga, M.

1990-08-01

The effect of magnetic fields to 15 T on electrical resistance has been measured for the BiSrCaCuO superconductor at precise temperatures during the transition to the superconducting state from pre-onset conditions to essentially zero resistance conditions. The results show that the temperature at which the magnetic field causes a divergence in the resistance versus 1000/ T curve is approximately the same temperature as the value at which, during cooling, the positive Hall coefficient begins its abrupt descent to zero. This temperature gives the best measure of Tc. It is also shown that small oscillations of low frequency start near onset conditions, the amplitude of which at a given temperature is B-field dependent. Additionally, Hall effect studies as a function of temperature at 4 T in three separate experiments (including high Tc BiSrCaCu PbO of > 90% theoretical density) show that sharp delta-function-like peaks in + RH are observed near Tc and are superimposed on a broader maximum. The Hall data are explicable in terms of exciton formation and ionization. The bound holes associated with these excitons are believed to be the mediators producing Cooper-pairing, and scale very well with Tc for all the known high Tc oxides.

Presentation of test cases TC-2A, TC-2B, TC-2C, TC-2D - Twodimensional, incompressible, wall flows with separation

DEFF Research Database (Denmark)

Scheel Larsen, Poul

1988-01-01

The four test cases comprise the backfacing step at high Re-number (TC-2A) and low Re-number (TC-2B), a low Re-number boundary layer flow past a thin obstacle, fence-on-wall (TC-2C), and a high Re-number developed channel flow past a squareobstacle (TC-2D). Geometry, test conditions and available...

Electrochemical investigations of high-Tc superconductors - low-temperature electrochemistry

International Nuclear Information System (INIS)

Lorenz, W.J.

1992-01-01

This research report presents a summary of results obtained by electrochemical investigations of high-Tc superconductors at room temperature and below the critical temperature (Tc). The studies were to reveal the behaviour of the ceramic superconducting materials at the interface between superconductor and ionic conductor. (MM) With 4 tabs., 8 figs [de

Annotated references on shielding experiment and calculation of high energy particles

International Nuclear Information System (INIS)

Hirayama, H.; Ban, S.; Nakamura, T.

1990-12-01

The literature on shielding experiment and calculation of high energy particles above 20 MeV has been surveyed. The survey covers thirteen journals, from 1965 up to 1989. For each paper, applicable information is listed on type and energy of the projectile, the accelerator used, composition and thickness of the target and shielding materials, shielding geometry, the experimental and calculational methods, and the quantities obtained. The references on shielding experiment and on shielding calculation are accessed through two indices which list the projectile-target and shielding material combination, shielding geometry and the projectile energy range. The literature on neutron, photon and hadron production from thick target bombarded by charged particles has been surveyed mainly from 1984 as a complement of the previous work. (author)

Computational methods for high-energy source shielding

International Nuclear Information System (INIS)

Armstrong, T.W.; Cloth, P.; Filges, D.

1983-01-01

The computational methods for high-energy radiation transport related to shielding of the SNQ-spallation source are outlined. The basic approach is to couple radiation-transport computer codes which use Monte Carlo methods and discrete ordinates methods. A code system is suggested that incorporates state-of-the-art radiation-transport techniques. The stepwise verification of that system is briefly summarized. The complexity of the resulting code system suggests a more straightforward code specially tailored for thick shield calculations. A short guide line to future development of such a Monte Carlo code is given

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)

Double-layer neutron shield design as neutron shielding application

Science.gov (United States)

Sariyer, Demet; Küçer, Rahmi

2018-02-01

The shield design in particle accelerators and other high energy facilities are mainly connected to the high-energy neutrons. The deep penetration of neutrons through massive shield has become a very serious problem. For shielding to be efficient, most of these neutrons should be confined to the shielding volume. If the interior space will become limited, the sufficient thickness of multilayer shield must be used. Concrete and iron are widely used as a multilayer shield material. Two layers shield material was selected to guarantee radiation safety outside of the shield against neutrons generated in the interaction of the different proton energies. One of them was one meter of concrete, the other was iron-contained material (FeB, Fe2B and stainless-steel) to be determined shield thicknesses. FLUKA Monte Carlo code was used for shield design geometry and required neutron dose distributions. The resulting two layered shields are shown better performance than single used concrete, thus the shield design could leave more space in the interior shielded areas.

Bi-Polaron Condensation in High Tc Superconductors

International Nuclear Information System (INIS)

Ranninger, J.

1995-01-01

On the basis of optical measurements-, photoemission-, EXAFS- and neutron scattering-experiments we conclude that itinerant valence electrons coexist with localized bi-polarons.Entering the metallic phase upon chemical doping, a charge transfer between the two electronic subsystems is triggered off. We show that as the temperature is lowered towards Tc this process leads to a delocalization of bi-polarons due to a precursor effect of superfluidity of those bi-polarons. Upon entering the superconducting phase, these bipolarons ultimately condense into a superfluid state which is expected to largely determine the superconducting properties of high Tc materials. (authors)

Terahertz emission and electromagnetic waves in single crystal Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} structures

Energy Technology Data Exchange (ETDEWEB)

Wieland, Raphael; Rudau, Fabian; Gross, Boris; Judd, Thomas; Koelle, Dieter; Kleiner, Reinhold [Physikalisches Institut and Center for Collective Quantum Phenomena in LISA" +, Universitaet Tuebingen, Tuebingen (Germany); Kinev, Nickolay; Koshelets, Valery [Kotel' nikov Institute of Radio Engineering and Electronics, Moscow (Russian Federation); Tsujimoto, Manabu [Kyoto University, Kyoto (Japan); Ji, Min; Huang, Ya; Zhou, Xianjing; An, Deyue; Wang, Huabing [National Institute for Materials Science, Tsukuba (Japan); Research Institute of Superconductor Electronics, Nanjing University, Nanjing (China); Wu, Peihang [Research Institute of Superconductor Electronics, Nanjing University, Nanjing (China); Hatano, Takeshi [National Institute for Materials Science, Tsukuba (Japan)

2015-07-01

Josephson Junctions (JJs) offer a natural way to convert a dc voltage into high-frequency electromagnetic radiation. In the high-Tc superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} (BSCCO), JJs form intrinsically, allowing to fabricate stacks of hundreds of junctions easily. Emission can occur at relatively low bias currents but also at larger input power with frequencies from 0.4 to 1 THz. At high bias, a hot spot forms, affecting both the intensity and the linewidth of the radiation. BSCCO mesas are believed to work as a cavity for electromagnetic standing waves, synchronizing all the junctions in the stack. We investigated THz emission and hotspot formation using a combination of transport measurements, electromagnetic wave detection via a superconducting receiver and low temperature scanning laser microscopy.

Temperature profile evolution in quenching high-Tc ...

Indian Academy of Sciences (India)

Abstract. Irreversible normal zones leading to quench is an important aspect of high-temperature superconductors (HTS) in all practical applications. As a consequence of quench, transport current gets diverted to the matrix stabilizer material of the high-Tc composite and causes Joule heating till the original conditions are ...

Mechanisms of conventional and high Tc superconductivity

International Nuclear Information System (INIS)

Kresin, V.L.; Morawitz, H.; Wolf, S.A.

1993-01-01

This book gives a careful and objective review of theories of superconductivity in traditional superconductors, organics, and high Tc cuprates. Of course, the authors do still present their own theories of cuprate superconductivity, but only in the final chapter after other possibilities have been discussed. The book should be especially useful for researchers entering the field of high Tc superconductivity. The reviews of photon mediated pairing and strong coupling theory are very welcome, since much of this material has not been reviewed since the classic 1969 volume edited by Parks. In particular the authors dispel the various myths that phonon mediated pairing leads to upper bounds on Tc. In addition to phonon mediated pairing the book discussed in detail pairing due to exchange of acoustic (demon) plasmons, excitons, or magnetic fluctuations. There have been so many diverse mechanisms based on strong correlation and large U Hubbard models that a book like this can only discuss a limited selection of the main contenders. In particular here the emphasis on Fermi liquid based models no doubt reflects the authors' own point of view. A whole chapter discusses the concepts of induced superconductivity, in the proximity effect, and its application to materials with several different electronic subsystems

Hot-cell shielding system for high power transmission in DUPIC fuel fabrication

International Nuclear Information System (INIS)

Kim, K.; Lee, J.; Park, J.; Yang, M.; Park, H.

2000-01-01

This paper presents a newly designed hot-cell shielding system for use in the development of DUPIC (Direct Use of spent PWR fuel In CANDU reactors) fuel at KAERI (Korea Atomic Energy Research Institute). This hot-cell shielding system that was designed to transmit high power to sintering furnace in-cell from the out-of-cell through a thick cell wall has three subsystems - a steel shield plug with embedded spiral cooling line, stepped copper bus bars, and a shielding lead block. The dose-equivalent rates of the hot-cell shielding system and of the apertures between this system and the hot-cell wall were calculated. Calculated results were compared with the allowable dose limit of the existing hot-cell. Experiments for examining the temperature changes of the shielding system developed during normal furnace operation were also carried out. Finally, gamma-ray radiation survey experiments were conducted by Co-60 source. It is demonstrated that, from both calculated and experimental results, the newly designed hot-cell shielding system meets all the shielding requirements of the existing hot-cell facility, enabling high power transmission to the in-cell sintering furnace. (author)

Pre-installation empirical testing of room shielding for high dose rate remote afterloaders

International Nuclear Information System (INIS)

Klein, E.E.; Grigsby, P.W.; Williamson, J.F.; Meigooni, A.S.

1993-01-01

PURPOSE: Many facilities are acquiring high dose rate remote afterloading units. It is economical that these units be placed in existing shielded teletherapy rooms. Scatter-radiation barriers marginally protect uncontrolled areas from a high dose rate source especially in a room that houses a non-dynamic Cobalt-60 unit. In addition the exact thickness and material composition of the barriers are unknown and therefore, a calculation technique may give misleading results. Also, it would be impossible to evaluate an entire wall barrier by taking isolated core samples in order to assist in the calculations. A quick and inexpensive measurement of dose equivalent using a rented high activity 192Ir source evaluates the barriers and locates shielding deficiencies. METHODS AND MATERIALS: We performed transmission calculations for primary and scattered radiation based on National Council on Radiation Protection and Measurements Reports 49 and 51, respectively. We then rented a high activity 21.7 Ci (8.03 x 10(11) Bq) Ir-192 source to assess our existing teletherapy room shielding for adequacy and voids. This source was placed at the proposed location for clinical high dose rate treatment and measurements were performed. RESULTS: No deficiencies were found in controlled areas surrounding the room, but large differences were found between the calculated and measured values. Our survey located a region in the uncontrolled area above the room requiring augmented shielding which was not predicted by the calculations. A canopy shield was designed to potentially augment the shielding in the ceiling direction. CONCLUSION: Pre-installation testing by measurement is an invaluable method for locating shielding deficiencies and avoiding unnecessary enhancement of shielding particularly when there is lack of information of the inherent shielding

Analysis of 99mTc-labeled radiopharmaceuticals by high-performance liquid chromatography

International Nuclear Information System (INIS)

Muto, Toshio

1990-01-01

High-performance liquid chromatography (HPLC) equiped with on line radiometric and optical detectors (i.e. radio-HPLC) have been applied to the radiochemical analysis of commonly-used 99m Tc-radio pharma ceuticals with a view point to check the radiochemical purities of the compounds. Chromatographic conditions were determined by examination of the types of column, mobile phase and pH. An aqueous size-exclusion (Shim-pack Diol-300) and reversed-phase column (Zorbax-ODS) were found to be suitable for 99m Tc-HSA and the other 99m Tc-agents, respectively. The analysis of low molecular weight 99m Tc-agents (e.g. 99m Tc-DTPA, 99m Tc-DMSA, 99m Tc-pyrophosphate, 99m Tc-phytic acid, 99m Tc-MDS, 99m Tc-HMDP) were done by reversed-phaseion pairing chromatography using a optimized mobile phase consisted on a mixture of 50 mM phosphate buffer (pH 7.0) and 2 mM TBA (tetra nbutyl) ammonium hydroxide) in 30 % methanol. The mobile phases for analysis of medium molecular weight 99m Tc-HSA were consisted of a mixture of 50 mM phosphate buffer (ph 7.0) in 30 % methanol, and a mixtures of 1 % SDS (sodium dodecyl sulfonate) in Tris buffer (pH. 7.0), respectively. It was apparent from the radio-chromatograms obtained from these chromatographic conditions, that impurity of 99m TcO 4 was observed in 99m Tc-pyrophosphate, 99m Tc-phytic acid, 99m Tc-MDP, 99m Tc-HMDP, and impurities of 99m Tc-labeled species and 99m TcO 4 , were observed in 99m Tc-HIDA, 99m Tc-HIDA, 99m Tc-HSA. The radiochemical impurities of the 99m Tc-radiopharmaceuticals were ranged between 90 and 100 %. From these results, radio-HPLC has been shown to be suitable method for analysis of 99m Tc-radiopharmaceuticals, with rapidity and excellent precision. (author)

Microstructural development of superconducting phases in Pb-BSCCO system derived from sol-gel technique

International Nuclear Information System (INIS)

Qureshi, A.H.; Hussain, N.; Durrani, S.K.; Waqas, H.; Arshad, M.

2010-01-01

Sol-gel processing technique has been utilized to produce the gel of Pb-BSCCO system (Bi/sub 2/-xPbxSr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10/+-y, where x 0.2, 0.4, and 0.8, are the mole fraction of Pb substituted against Bi). The gel samples were subsequently heated to 800 deg. C for 2 h to obtain the powders which were then pressed and sintered at 845 deg. C for 60 h. The morphologies in the Pb-BSCCO gel, powder and sintered products were observed with scanning electron microscope (SEM) and optical microscope. The plate-like growths of the superconducting phases are evident from the SEM micrographs. The optical micrographs of sintered samples showed that the samples containing 0.2 and 0.8 mole fraction of Pb mainly consisted of dark grey and white regions, while sample having 0.4 mole fraction of Pb comprised of dark grey, light grey, and white regions. The different regions were analyzed by using energy dispersive X-rays (EDX) analyzer attached with SEM. The results revealed that the dark grey regions in all the samples represented the Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8/ +- y (2212) phase whereas, light grey regions in sample (x = 0.4) constituted the Bi/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10/ +- y (2223) phase. The white regions in all samples depicted the presence of CuO. The best result in term of larger fraction of superconducting phase (2223) has been observed in sample containing 0.4 mole fraction of Pb. (author)

Plasma resonance and flux dynamics in layered high-Tc superconductors

DEFF Research Database (Denmark)

Pedersen, Niels Falsig; Sakai, S.

2000-01-01

Flux dynamics of layered high Tc superconductors are considered with special emphasis on the small oscillation modes. In particular we find the dispersion relation for the plasma modes and discuss the spectra to be observed in microwave experiments.......Flux dynamics of layered high Tc superconductors are considered with special emphasis on the small oscillation modes. In particular we find the dispersion relation for the plasma modes and discuss the spectra to be observed in microwave experiments....

Simplified shielding calculation system for high-intensity proton accelerators

Energy Technology Data Exchange (ETDEWEB)

Masumura, Tomomi; Nakashima, Hiroshi; Nakane, Yoshihiro; Sasamoto, Nobuo [Center for Neutron Science, Tokai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)

2000-06-01

A simplified shielding calculation system is developed for applying conceptual shielding design of facilities in the joint project for high-intensity proton accelerators. The system is composed of neutron transmission calculation part for bulk shielding using simplified formulas: Moyer model and Tesch's formula, and neutron skyshine calculation part using an empirical formula: Stapleton's formula. The system is made with the Microsoft Excel software for user's convenience. This report provides a manual for the system as well as calculation conditions used in the calculation such as Moyer model's parameters. In this report preliminary results based on data at December 8, 1999, are also shown as an example. (author)

Dependence of critical current on sample length analyzed by the variation of local critical current bent of BSCCO superconducting composite tape

International Nuclear Information System (INIS)

Matsubayashi, H.; Mukai, Y.; Shin, J.K.; Ochiai, S.; Okuda, H.; Osamura, K.; Otto, A.; Malozemoff, A.

2008-01-01

Using the high critical current type BSCCO composite tape fabricated at American Superconductor Corporation, the relation of overall critical current to the distribution of local critical current and the dependence of overall critical current on sample length of the bent samples were studied experimentally and analytically. The measured overall critical current was described well from the distribution of local critical current and n-value of the constituting short elements, by regarding the overall sample to be composed of local series circuits and applying the voltage summation model. Also the dependence of overall critical current on sample length could be reproduced in computer satisfactorily by the proposed simulation method

Early high-Tc commercial activity

International Nuclear Information System (INIS)

Anon.

1988-01-01

The high temperature superconductors have already begun to generate the first stirrings of commercial activity. Companies that supply instruments and chemicals to researchers have enjoyed increased business. At least one company has begun to supply educational materials. Venture capital firms have invested about $15 million in startups to capitalize on developments in high-field applications, superconducting electronics, and magnetic shielding. Consulting firms are gathering and selling market research information. And the federal government is studying the question of how to cooperate with American companies to commercialize the research taking place in the national laboratories. This article discusses these issues

On the application of High-Tc superconductors in power coils and transformers

NARCIS (Netherlands)

Chevtchenko, O.A.

2002-01-01

In this study, the electro-magnetic properties of high-Tc tapes and coils are investigated. The focus is on Bi-2223/Ag tapes with non-twisted superconducting filaments as these are the only high-Tc superconductors at present available in sufficient length for practical applications. The study is

Magneto-optical imaging of magnetic flux distribution in high-Tc superconductors

International Nuclear Information System (INIS)

Ueno, K.; Murakamia, H.; Kawayama, I.; Doda, Y.; Tonouchi, M.; Chikumoto, N.

2004-01-01

Prototype systems of home-made magneto-optical microscopes were fabricated, and preliminary studies were carried out using Bi 2 Sr 2 CaCu 2 O 8+δ single crystals and an YBa 2 Cu 3 O 7-δ superconductor vortex flow transistor. In the study using BSCCO crystals, we succeeded in the observation of magnetic flux penetration into half-peeled thin flake region on the crystal surface, and it was found that the magnetic fluxes penetrate in characteristic one-dimensional alignment almost along the crystal a-axis. On the other hand, in the study using the YBCO device clear changes in the generated magnetic field distribution could be detected corresponding to the current direction

Practical aspects of shielding high-energy particle accelerators

International Nuclear Information System (INIS)

Thomas, R.H.; Univ. of California, Berkeley, CA

1993-09-01

The experimental basis of shielding design for high-energy accelerators that has been established over the past thirty years is described. Particular emphasis is given to the design of large accelerators constructed underground. The first data obtained from cosmic-ray physics were supplemented by basic nuclear physics. When these data proved insufficient, experiments were carried out and interpreted by several empirical formulae -- the most successful of which has been the Moyer Model. This empirical model has been used successfully to design the shields of most synchrotrons currently in operation, and is still being used in preliminary design and to check the results of neutron transport calculations. Accurate shield designs are needed to reduce external radiation levels during accelerator operations and to minimize environmental impacts such as open-quotes skyshineclose quotes and the production of radioactivity in groundwater. Examples of the cost of minimizing such environmental impacts are given

Development of highly effective neutron shields and neutron absorbing materials

International Nuclear Information System (INIS)

Tsuda, K.; Matsuda, F.; Taniuchi, H.; Yuhara, T.; Iida, T.

1993-01-01

A wide range of materials, including polymers and hydrogen-occluded alloys that might be usable as the neutron shielding material were examined. And a wide range of materials, including aluminum alloys that might be usable as the neutron-absorbing material were examined. After screening, the candidate material was determined on the basis of evaluation regarding its adaptabilities as a high-performance neutron-shielding and neutron-absorbing material. This candidate material was manufactured for trial, after which material properties tests, neutron-shielding tests and neutron-absorbing tests were carried out on it. The specifications of this material were thus determined. This research has resulted in materials of good performance; a neutron-shielding material based on ethylene propylene rubber and titanium hydride, and a neutron-absorbing material based on aluminum and titanium hydride. (author)

Internal friction around Tc connected with superconductivity in high Tc superconductors

International Nuclear Information System (INIS)

Wang Yening

1993-01-01

Internal friction and ultrasonic measurements show that there always exists a phase-like transition (PLT) characterized by the jump of lattice parameters at tens degrees above Tc in superconducting YBaCuO, BiSrCaCuO and TlBaCaCuO. Ferroelastic loops and shape memory effect associated with elastic softening invariably occur at the PLT temperature, showing the characteristics of thermoelastic martensitic transition. Internal frictions in KHz of Bi(Pb)SrCaCuO reveal a static hysteretic plateau (Qp -1 ) above Tc that drops linearly with temperature below Tc. The Qp -1 of YBaCuO decreases with decreasing oxygen content. The origin of the hysteretic Qp -1 is attributed to the lattice distortions around the carriers. (orig.)

Effect of milking efficiency on Tc-99 content of Tc-99m derived from Tc-99m generators

International Nuclear Information System (INIS)

Bonnyman, J.

1983-01-01

Tc-99m obtained by separation from its parent Mo-99 always contains Tc-99 produced by decay of Tc-99m and Mo-99. Factors effecting the Tc-99/Tc-99m ratios are discussed. An HPLC method has been developed to measure the 99 TcO 4- content of sodium pertechnetate from generators with a detection limit of 0.9 ng Tc-99 for a 500 μl/ aliquot of TcO 4- -99m. First eluates of 10 chromatograph-ic generators gave Tc-99/Tc-99m ratios ranging from 3.5-46 ng Tc/mCi Tc-99m measured at the time of milking. The measurements indicate that Tc-99/Tc-99m ratios high enough to cause adverse labelling effects could be found in 'instant pertechnetate' and in the first eluate from Tc-99m generators for the activities normally used in radiopharmaceutical production

Metallorganic precursors route for high Tc superconducting materials and related phases

International Nuclear Information System (INIS)

Beltran-porter, D.; Gonzalez, A.; Sanchis, M.J.; Beltran-porter, A.; Ibanez, R.; Sapina, F.

1991-01-01

The adequacy of the precursors approach for high Tc superconducting materials is validated by means of three examples of a new synthesis of mixed oxides which are directly related to the high Tc superconductors. The synthesis temperature is lowered significantly, and the need for extending the classic 'building block' approach is shown. The hypothesis that topochemical reactions from molecular to extended solids are posssible is proven. 28 refs

In-house cyclotron production of high-purity Tc-99m and Tc-99m radiopharmaceuticals.

Science.gov (United States)

Martini, Petra; Boschi, Alessandra; Cicoria, Gianfranco; Zagni, Federico; Corazza, Andrea; Uccelli, Licia; Pasquali, Micòl; Pupillo, Gaia; Marengo, Mario; Loriggiola, Massimo; Skliarova, Hanna; Mou, Liliana; Cisternino, Sara; Carturan, Sara; Melendez-Alafort, Laura; Uzunov, Nikolay M; Bello, Michele; Alvarez, Carlos Rossi; Esposito, Juan; Duatti, Adriano

2018-05-30

In the last years, the technology for producing the important medical radionuclide technetium-99m by cyclotrons has become sufficiently mature to justify its introduction as an alternative source of the starting precursor [ 99m Tc][TcO 4 ] - ubiquitously employed for the production of 99m Tc-radiopharmaceuticals in hospitals. These technologies make use almost exclusively of the nuclear reaction 100 Mo(p,2n) 99m Tc that allows direct production of Tc-99m. In this study, it is conjectured that this alternative production route will not replace the current supply chain based on the distribution of 99 Mo/ 99m Tc generators, but could become a convenient emergency source of Tc-99m only for in-house hospitals equipped with a conventional, low-energy, medical cyclotron. On this ground, an outline of the essential steps that should be implemented for setting up a hospital radiopharmacy aimed at the occasional production of Tc-99m by a small cyclotron is discussed. These include (1) target production, (2) irradiation conditions, (3) separation/purification procedures, (4) terminal sterilization, (5) quality control, and (6) Mo-100 recovery. To address these issues, a comprehensive technology for cyclotron-production of Tc-99m, developed at the Legnaro National Laboratories of the Italian National Institute of Nuclear Physics (LNL-INFN), will be used as a reference example. Copyright © 2018 Elsevier Ltd. All rights reserved.

Scavenging of Tc(V) formed by I.T. in 95mTcO4- solutions

International Nuclear Information System (INIS)

Ianoz, E.; Colin, M.; Kosinski, M.

1988-01-01

The chemical effects of the I.T. of 95m Tc in 95m TcO 4 - have been studied in chelating ligand solutions. At high pH and at high concentration of 1,4,8,11-tetraazacyclotetradecane and 1,4-dithia-8, 11-diazacyclotetradecane, the retention of 95g Tc is about 20% and the unretained 95g Tc appears preponderantly (ca. 73%) as [TcO 2 L] + complexes. In glucoheptonate solution, the 95g Tc retention remains practically the same (22%) but the unretained 95g Tc is found in high proportion (73%) as [TcObis(glucoheptonate)] - . The added ligands are very good scavengers for 95g Tc(V). A comparison is made between 95g Tc species formed by the I.T. in 95m TcO 4 - and 99m Tc species resulting from the chemical reduction of 99m TcO 4 - . (orig.)

Tumor affinity of technetium-99m labeled radiopharmaceuticals. II. Sup(99m)Tc-Sn-diphosphonate (sup(99m)Tc-EHDP), sup(99m)Tc-Sn-dimercaptosuccinic acid (sup(99m)Tc-DMSA), sup(99m)Tc-Sn-diethyl stilbestrol diphosphate (sup(99m)Tc-DSDP)

Energy Technology Data Exchange (ETDEWEB)

Itoh, K; Kobayashi, S; Hisada, K; Tonami, N [Kanazawa Univ. (Japan). School of Medicine; Ando, A

1976-10-01

The authors have examined the tumor affinity of various sup(99m)Tc-labelled radiopharmaceuticals to Ehrlich's tumor for the purpose of delineating human malignant neoplasm positively. The biologic distributions of sup(99m)Tc-Sn-diphosphonate (sup(99m)Tc-EHDP), sup(99m)Tc-Sn-dimercaptosuccinic acid (sup(99m)Tc-DMSA) and sup(99m)Tc-Sn-diethyl stilbestrol diphosphate (sup(99m)Tc-DSDP, sup(99m)Tc-Honvan) are included as the second report on the tumor affinity of Ehrlich-bearing mice. Tumor concentration of sup(99m)Tc-EHDP was lowest and the positive delineation of implanted tumor with sup(99m)Tc-EHDP was poorest in sequential images, though active accumulation in some soft tissues malignant neoplasms, breast cancer, and thyroid cancer, has been reported. Tumor concentration and the tumor-to-blood ratio of sup(99m)Tc-DMSA were not so high, contrary to our expectation that /sup 197/Hg-DMSA might show high tumor concentration and high tumor-to-blood ratio the same as /sup 197/Hg chlormerodrin of the renal scanning radiopharmaceuticals. Tumor concentration of sup(99m)Tc-DSDP was highest. The tumor-to-blood concentration ratio was lower than that of the above mentioned radiopharmaceuticals but the tumor-to-liver ratio and/or tumor-to-lung ratio was over 1.0 at the earlier time. Biologic distribution of sup(99m)Tc-DSDP was similar to that of /sup 32/P labeled DSDP. It is presumed that sup(99m)Tc is labeled at the phosphate ester of DSDP which is dephospholytated immediately by phospholylase in vivo following intravenous injection. Although it is not known precisely it may be assumed that the mechanism of accumulating sup(99m)Tc-DSDP in Ehrlich's tumor is related to the phospholylase activity in neoplasms.

Robust high-yield ~1 TBq production of cyclotron based sodium [99mTc]pertechnetate.

Science.gov (United States)

Andersson, J D; Thomas, B; Selivanova, S V; Berthelette, E; Wilson, J S; McEwan, A J B; Gagnon, K

2018-03-02

This paper presents the irradiation and processing of high-current 100 Mo targets at the University of Alberta (UofA) in a GMP compliant setting. For purpose of comparison with a second production facility, additional studies at Centre Hospitalier Universitaire de Sherbrooke (CHUS) are also described. More than 70% of today's diagnostic radiopharmaceuticals are based on 99m Tc, however the conventional supply chain for obtaining 99m Tc is fragile. The aim of this work was to demonstrate reliable high yield production and processing of 99m Tc with medium-energy, high-current, cyclotrons. We used two cyclotrons (TR-24, Advanced Cyclotron Systems, Inc) for irradiations with 22 MeV or 24 MeV incident energy and 400 μA current up to a maximum of 6 h. The irradiated 100 Mo was dissolved using peroxide, basified using ammonium carbonate, and purified using a PEG-based solid phase extraction technique. High-yield productions with 22 MeV (400 μA, 6 h) yielded an average isolated [ 99m Tc]TcO 4 - yield of 878 GBq ± 99 GBq (23.7 Ci ± 2.7 Ci) decay corrected to EOB, n = 8 (isolated saturation yield: 4.36 ± 0.49 GBq/μA). Irradiations with 24 MeV (400 μA, 6 h) resulted in an average isolated [ 99m Tc]TcO 4 - yield of 993 GBq ± 100 GBq (26.8 Ci ± 2.7 Ci) decay corrected to EOB, n = 7 (isolated saturation yield: 4.97 ± 0.50 GBq/μA). These yields corresponds to 600-700 GBq (16-19 Ci) of [ 99m Tc]TcO 4 - at release (i.e. 3 hour post-EOB). For all tested batches, the QC results were within the recently published specifications in the European Pharmacopoeia. Reliable near-TBq production yields for 99m Tc can be obtained using medium-energy cyclotrons. This work presents evidence that medium-energy high-current cyclotrons can provide high yields of [ 99m Tc]TcO 4 - with radionuclidic impurities levels within the specifications of the existing European Pharmacopoeia monograph, indicating that this

Radiation Build-Up Of High Energy Gamma In Shielding Of High Atomic Number

International Nuclear Information System (INIS)

Yuliati, Helfi; Akhadi, Mukhlis

2000-01-01

Research to observe effect of radiation build-up factor (b) in iron (Fe) and lead (Pb) for high energy gamma shielding from exp.137 Cs (E gamma : 662 keV) and exp.60 Co (E gamma : 1332 keV) sources has been carried out. Research was conducted bt counting of radiation intensity behind shielding with its thickness vary from 1 to 5 times of half value thickness (HVT). NaI (TI) detector which connected to multi channel analyzer (MCA) was used for the counting. Calculation result show that all of b value are near to 1 (b∼1) both for Fe and Pb. Without inserting b in calculation, from the experiment it was obtained HVT value of Fe for high gamma radiation of 662 and 1332 keV were : (12,94 n 0,03) mm and (17,33 n 0,01) mm with their deviation standards were 0,2% and 0,06% respectively. Value of HVT for Pb with the same energy were : (6,31 n 0,03) mm and (11,86 n 0,03) mm with their deviation standars were : 0,48% and 0,25% respectively. HVL concept could be applied directly to estimate shielding thickness of high atomic number of high energy gamma radiation, without inserting correction of radiation build-up factor

Single crystal Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} structures as THz-emitters

Energy Technology Data Exchange (ETDEWEB)

Wieland, Raphael; Rudau, Fabian; Langer, Julian; Koelle, Dieter; Kleiner, Reinhold [Physikalisches Institut and Center for Collective Quantum Phenomena in LISA+, Universitaet Tuebingen, Tuebingen (Germany); Kinev, Nickolay; Koshelets, Valery [Kotel' nikov Institute of Radio Engineering and Electronics, Moscow (Russian Federation); Yuan, Jie; Ishii, Akira; Hatano, Takeshi [National Institute for Materials Science, Tsukuba (Japan); Huang, Ya; Ji, Min; Zhou, Xianjing; Wang, Huabing [National Institute for Materials Science, Tsukuba (Japan); Research Institute of Superconductor Electronics, Nanjing University, Nanjing (China); Wu, Peiheng [Research Institute of Superconductor Electronics, Nanjing University, Nanjing (China)

2016-07-01

By means of Josephson Junctions (JJs) one can easily convert a dc voltage into high-frequency electromagnetic radiation. The high-Tc superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} (BSCCO) has a layered crystal structure in such a way that JJs form intrinsically. This allows to fabricate hundreds of stacked junctions with reasonable effort. Terahertz emission can be observed at relatively low bias currents but also at higher input power. Emission frequencies from 0.4 to 2.4 THz have been measured. A hot spot forms at high bias currents with effect on both intensity and linewidth of the THz emission.BSCCO mesas probably act as a cavity for electromagnetic standing waves that synchronize all junctions in the stack. We investigated hotspot formation and THz emission using a combination of transport measurements, low temperature scanning laser microscopy and electromagnetic wave detection via a superconducting receiver.

Neutron shielding properties of a new high-density concrete

International Nuclear Information System (INIS)

Lorente, A.; Gallego, E.; Vega Carrillo, H.R.; Mendez, R.

2008-01-01

The neutron shielding properties of a new high-density concrete (commercially available under the name Hormirad TM , developed in Spain by the company CT-RAD) have been characterized both experimentally and by Monte Carlo calculations. The shielding properties of this concrete against photons were previously studied and the material is being used to build bunkers, mazes and doors in medical accelerator facilities with good overall results. In this work, the objective was to characterize the material behaviour against neutrons, as well as to test alternative mixings including boron compounds in an effort to improve neutron shielding efficiency. With that purpose, Hormirad TM slabs of different thicknesses were exposed to an 241 Am-Be neutron source under controlled conditions in the neutron measurements laboratory of the Nuclear Engineering Department at UPM. The original mix, which includes a high fraction of magnetite, was then modified by adding different proportions of anhydrous borax (Na 2 B 4 O 7 ). In order to have a reference against common concrete used to shield medical accelerator facilities, the same experiment was repeated with ordinary (HA-25) concrete slabs. In parallel to the experiments, Monte Carlo calculations of the experiments were performed with MCNP5. The experimental results agree reasonably well with the Monte Carlo calculations. Therefore, the first and equilibrium tenth-value layers have been determined for the different types of concrete tested. The results show an advantageous behaviour of the Hormirad TM concrete, in terms of neutron attenuation against real thickness of the shielding. Borated concretes seem less practical since they did not show better neutron attenuation with respect to real thickness and their structural properties are worse. The neutron attenuation properties of Hormirad TM for typical neutron spectra in clinical LINAC accelerators rooms have been also characterized by Monte Carlo calculation. (author)

[Trial manufacture of a plunger shield for a disposable plastic syringe].

Science.gov (United States)

Murakami, Shigeki; Emoto, Takashi; Mori, Hiroshige; Fujita, Katsuhisa; Kubo, Naoki

2008-08-20

A syringe-type radiopharmaceutical being supplied by a manufacturer has a syringe shield and a plunger shield, whereas an in-hospital labeling radiopharmaceutical is administered by a disposable plastic syringe without the plunger shield. In cooperation with Nihon Medi-Physics Co. Ltd., we have produced a new experimental plunger shield for the disposable plastic syringe. In order to evaluate this shielding effect, we compared the leaked radiation doses of our plunger shield with those of the syringe-type radiopharmaceutical (Medi shield type). Our plunger shield has a lead plate of 21 mm in diameter and 3 mm thick. This shield is equipped with the plunger-end of a disposal plastic syringe. We sealed 99mTc solution into a plastic syringe (Terumo Co.) of 5 ml with our plunger shield and Medi shield type of 2 ml. We measured leaked radiation doses around syringes using fluorescent glass dosimeters (Dose Ace). The number of measure points was 18. The measured doses were converted to 70 microm dose equivalent at 740 MBq of radioactivity. The results of our plunger shield and the Medi shield type were as follows: 4-13 microSv/h and 3-14 microSv/h at shielding areas, 3-545 microSv/h and 6-97 microSv/h at non-shielding areas, 42-116 microSv/h and 88-165 microSv/h in the vicinity of the syringe shield, and 1071 microSv/h and 1243 microSv/h at the front of the needle. For dose rates of shielding areas around the syringe, the shielding effects were approximately the same as those of the Medi shield type. In conclusion, our plunger shield may be useful for reducing finger exposure during the injection of an in-hospital labeled radiopharmaceutical.

Pinning and creep in high-Tc superconductors

International Nuclear Information System (INIS)

Ovchinnikov, Yu.N.; Ivlev, B.I.

1992-01-01

The angular and magnetic field dependence of a critical current parallel to the layers in the layered superconductors is studied. The critical current value is found for a superconductor with strong pinning centers. Quantum flux creep in sufficiently perfect layered high-Tc superconductors is discussed. The cross-over temperature between activated and quantum creep is found. (orig.)

Plasma resonance in anisotropic layered high-Tc superconductors

DEFF Research Database (Denmark)

Sakai, Shigeki; Pedersen, Niels Falsig

1999-01-01

The plasma resonance is described theoretically by the inductive coupling model for a large stacked Josephson-junction system such as the intrinsic Josephson-junction array in anisotropic high- T-c superconductors. Eigenmodes of the plasma oscillation are analytically described and a numerical...

Shielding design of highly activated sample storage at reactor TRIGA PUSPATI

International Nuclear Information System (INIS)

Naim Syauqi Hamzah; Julia Abdul Karim; Mohamad Hairie Rabir; Muhd Husamuddin Abdul Khalil; Mohd Amin Sharifuldin Salleh

2010-01-01

Radiation protection has always been one of the most important things considered in Reaktor Triga PUSPATI (RTP) management. Currently, demands on sample activation were increased from variety of applicant in different research field area. Radiological hazard may occur if the samples evaluation done were misjudge or miscalculated. At present, there is no appropriate storage for highly activated samples. For that purpose, special irradiated samples storage box should be provided in order to segregate highly activated samples that produce high dose level and typical activated samples that produce lower dose level (1 - 2 mR/ hr). In this study, thickness required by common shielding material such as lead and concrete to reduce highly activated radiotracer sample (potassium bromide) with initial exposure dose of 5 R/ hr to background level (0.05 mR/ hr) were determined. Analyses were done using several methods including conventional shielding equation, half value layer calculation and Micro shield computer code. Design of new irradiated samples storage box for RTP that capable to contain high level gamma radioactivity were then proposed. (author)

Shielding augmentation of roll-on shield from NAPS to Kaiga-2

International Nuclear Information System (INIS)

Pradhan, A.S.; Kumar, A.N.

2000-01-01

Extensive radiation field surveys were conducted in NAPS and KAPS reactor buildings as a part of commissioning checks on radiation shielding. During such surveys, dose rate higher than the expected values were noticed in fuelling machine service areas. A movable shield, separating high field area fuelling machine vault and low field area fuelling machine service area, known as roll-on shield was identified as one of the causes of high field in fuelling machine service area along with weaker end-shield. This paper discusses systematic approach adopted in bringing down the dose rates in fuelling machine service area by augmentation of roll-on shield. (author)

Electromagnetic shielding

International Nuclear Information System (INIS)

Tzeng, Wen-Shian V.

1991-01-01

Electromagnetic interference (EMI) shielding materials are well known in the art in forms such as gaskets, caulking compounds, adhesives, coatings and the like for a variety of EMI shielding purposes. In the past, where high shielding performance is necessary, EMI shielding has tended to use silver particles or silver coated copper particles dispersed in a resin binder. More recently, aluminum core silver coated particles have been used to reduce costs while maintaining good electrical and physical properties. (author). 8 figs

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

International Nuclear Information System (INIS)

Warren-Forward, H.; Cardew, P.; Smith, B.; Clack, L.; McWhirter, K.; Johnson, S.; Wessel, K.

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, 9 cm 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 99m Tc labelled radiopharmaceutical. (authors)

Risks in production and utilisation of labelled compounds for nuclear medicine. 2. Benefits and risks of utilization of 99mTc generator in nuclear medicine

International Nuclear Information System (INIS)

Olteanu-Chiper, D.; Barna, C.; Gard, E.; Negoita, N.

1999-01-01

The growth of radioisotope applications in nuclear medicine, imposed the reduction of the radiation effects and so, the reduction of associated risk of these applications. The utilization of radioactive isotopes for investigations in nuclear medicine is conditioned by the chemical behaviour and the means of detection of the emitted radiation on one hand, and by the radiation doses received by the patient, on the other hand. In these conditions, the nuclear medicine uses only the radioisotopes which are short half-time and low radiation energy, but high enough to be detected from the exterior of human body, 99m Tc being the most favourable for utilization in diagnostic purpose. This advantage is increased by the multiple possibilities to obtain different chemical forms with 99m Tc included, which permit the production of a large variety of radiopharmaceutical products, having a specific localization in the human body (organ-targets), thus allowing the diagnosis of numerous diseases. In the work the benefits and risks of the 99m Tc-Generator utilization in the nuclear medicine are shown and the utilization technique in these applications is presented . The 99m Tc-Generator is a compact chromatographic system, with lead shielding, which permits the elution of a sterile, pyrogen-free, injectable sodium pertechnetate solution, from an aluminium chromatographic column which keeps the 99 Mo. The 99m Tc-Generator system ensures the operator protection. The radioactive solution with 99m Tc is obtained in a closed vial, within lead shielding, the irradiation or contamination risks being mostly reduced. The utilization of 99m Tc in scintigraphic exam for diagnostic medicine implies a labelling operation with 99m Tc chemically bounded in forms appropriate to the target-organ and than the intravenously injection in doses dependent on the specific scintigraphic investigation or examination. (authors)

Integrated-circuit microwave detector based on granular high-Tc thin films. [Y-Ba-Cu-O

Energy Technology Data Exchange (ETDEWEB)

Drobinin, A.V.; Lutovinov, V.S.; Starostenko, I.V. (Moscow Inst. of Radioengineering, Electronics and Automation, (MIREA), Moscow (USSR))

1991-12-01

A highly sensitive integrative-circuit microwave detector based on granular High-Tc film has been designed. All matching circuits and High-Tc microbridge are located on the same substrate. The voltage responsivity 10{sup 3} V/W has been found at 65 K and frequency 5 GHz. Different modes of microwave detection have been observed: bolometric response near Tc in high-quality films, rectification mode caused by an array of weak links dominating in low-quality films, detection caused by nonlinear magnetic flux motion. (orig.).

High-performance magnetic field sensor based on superconducting quantum interference filters

Science.gov (United States)

Caputo, P.; Oppenländer, J.; Häussler, Ch.; Tomes, J.; Friesch, A.; Träuble, T.; Schopohl, N.

2004-08-01

We have developed an absolute magnetic field sensor using a superconducting quantum interference filter (SQIF) made of high-Tc grain-boundary Josephson junctions. The device shows the typical magnetic-field-dependent voltage response V(B ), which is a sharp deltalike dip in the vicinity of zero-magnetic field. When the SQIF is cooled with magnetic shield, and then the shield is removed, the presence of the ambient magnetic field induces a shift of the dip position from B0≈0 to a value B ≈B1, which is about the average value of the Earth's magnetic field, at our latitude. When the SQIF is cooled in the ambient field without shielding, the dip is first found at B ≈B1, and the further shielding of the SQIF results in a shift of the dip towards B0≈0. The low hysteresis observed in the sequence of experiments (less than 5% of B1) makes SQIFs suitable for high precision measurements of the absolute magnetic field. The experimental results are discussed in view of potential applications of high-Tc SQIFs in magnetometry.

Development of 99mTc labelled somatostatin analogues with high affinity for somatostatin receptors

International Nuclear Information System (INIS)

Maina, T.; Nock, B.; Nicolopoulou, A.; Tsipra, C.; Poppe, M.; Chiotellis, E.

2001-01-01

A recent development in oncology involves the use of metabolically stabilized peptide hormone analogues labelled with metallic radionuclides for the diagnosis or therapy of malignant disease. This approach was successfully applied for the first time in the visualization of somatostatin positive tumours and their metastases with 111 In DTPA-octreotide. In an effort to obtain a 99m Tc somatostatin receptor affine radioligand we describe herein the synthesis, radiochemistry and preliminary biological evaluation of two novel 99m Tc labelled somatostatin analogues, N 4 -TOC and N 4 -RC-160. In these compounds a tetraamine bifunctional unit was covalently attached to the N-terminal (D)Phe 1 of the peptide chain using Boc-protection strategies. The peptide conjugates were purified by high performance liquid chromatography (HPLC) and characterized by UV/Vis and ES-MS spectroscopies. As revealed by HPLC, 99m Tc labelling was quantitative under mild conditions, leading to a single 99m Tc species in high specific activities. Affinity of 99m Tc N 4 -TOC for the somatostatin receptor, as determined by in vitro binding assays in rat brain cortex membranes, was found unaffected by the presence of the bulky metal chelate. The binding properties of 99m Tc N 4 -RC-160 could not be determined by this assay due to an extremely high non-specific binding of this radioligand, and will be shortly investigated by other methods. Tissue distribution in healthy mice revealed that 99m Tc N 4 -TOC is clearing mainly through the kidneys and the urinary tract whereas 99m Tc N 4 -RC-160 shows a high accumulation in the liver as a result of its lipophilicity. Analysis of urine samples by HPLC showed that 99m Tc N 4 -TOC is excreted integer from the body of mice, while 99m Tc N 4 -RC-160 is totally transformed to an unidentified hydrophilic metabolite in vivo. The location of this metabolism is currently investigated. In vivo blocking experiments using animals pre-treated with 50 μg octreotide

Spectroscopic Characterization of Aqua [ fac-Tc(CO)3]+ Complexes at High Ionic Strength.

Science.gov (United States)

Chatterjee, Sayandev; Hall, Gabriel B; Engelhard, Mark H; Du, Yingge; Washton, Nancy M; Lukens, Wayne W; Lee, Sungsik; Pearce, Carolyn I; Levitskaia, Tatiana G

2018-06-05

Understanding fundamental Tc chemistry is important to both the remediation of nuclear waste and the reprocessing of nuclear fuel; however, current knowledge of the electronic structure and spectral signatures of low-valent Tc compounds significantly lags behind the remainder of the d-block elements. In particular, identification and treatment of Tc speciation in legacy nuclear waste is challenging due to the lack of reference data especially for Tc compounds in the less common oxidation states (I-VI). In an effort to establish a spectroscopic library corresponding to the relevant conditions of extremely high ionic strength typical for the legacy nuclear waste, compounds with the general formula of [ fac-Tc(CO) 3 (OH 2 ) 3- n (OH) n ] 1- n (where n = 0-3) were examined by a range of spectroscopic techniques including 99 Tc/ 13 C NMR, IR, XPS, and XAS. In the series of monomeric aqua species, stepwise hydrolysis results in the increase of the Tc metal center electron density and corresponding progressive decrease of the Tc-C bond distances, Tc electron binding energies, and carbonyl stretching frequencies in the order [ fac-Tc(CO) 3 (OH 2 ) 3 ] + > [ fac-Tc(CO) 3 (OH 2 ) 2 (OH)] > [ fac-Tc(CO) 3 (OH 2 )(OH) 2 ] - . These results correlate with established trends of the 99 Tc upfield chemical shift and carbonyl 13 C downfield chemical shift. The lone exception is [ fac-Tc(CO) 3 (OH)] 4 which exhibits a comparatively low electron density at the metal center attributed to the μ 3 -bridging nature of the - OH ligands causing less σ-donation and no π-donation. This work also reports the first observations of these compounds by XPS and [ fac-Tc(CO) 3 Cl 3 ] 2- by XAS. The unique and distinguishable spectral features of the aqua [ fac-Tc(CO) 3 ] + complexes lay the foundation for their identification in the complex aqueous matrixes.

The effect of long annealing on Pb-doped high-Tc Bi-Sr-Ca-Cu-O systems

Energy Technology Data Exchange (ETDEWEB)

Chandra, S.; Agnihotry, S.A.; Asthana, P.; Nagpal, K.C.; Saini, K.K.; Chanderkant; Sharma, C.P.; Ekbote, S.N. (National Physical Lab., New Delhi (India))

1991-01-16

The lead doped Bi based copper oxide high-Tc superconductors with different nominal compositions and with different annealing time periods are studied. The highest Tc (zero) achieved is 112 K in bulk phase 2223. The varying intensity of the low angle line at 2{theta}{approx equal}4.7deg suggests the gradual formation of the high-Tc phase due to the long annealing of nearly 200 to 250 h. It is also found that the high-Tc phase starts degrading after 250 h of annealing and Tc reduces. The distortion of the 2223 phase is suggested by the broadening of different XRD peaks, also the SEM studies support the above contention. The EDAX studies show no presence of Pb in the crystallites. (orig.).

Critical temperatures Tc estimated by Josephson-junction array model of layered high Tc superconductors

International Nuclear Information System (INIS)

Kawabata, C.; Shenoy, S.R.; Bishop, A.R.

1994-11-01

We model high T c superconductors (HTS) by quantum capacitive Josephson junction arrays (JJA), with Angstrom-scale parameters, to obtain an estimate of Tc trends. The basic idea is as follows. Number (or change) and phase are conjugate variables, with the uncertainty products obeying ΔN · Δ Θ > 1. Thus, in HTS, global phase coherence is opposed by charging-energy induced quantum phase fluctuations, especially across Josephson-coupled CuO 2 planes. These have separation d 1 and effective interplanar dielectric constant ε, e.g. from Y atoms in YBaCuO. Decreasing the interplane charging energy E 0 perpendicular to ∼ d 1 /ε, raises Tc. In Section 1, we motivate a modelling of HTS phase excitations by a quantum capacitive 3D JJA model, with XY planar phases. Section 2 gives a physical picture of the HTS transition, relating the complex layered HTS structure to a simpler ''intermediate level'' quantum 3D JJA/XY model. Section 3 sets up a path integral (3+1)D model that reduces to a previously studied anisotropic 3D XY/JJA model, with constants renormalized in some way, by the capacitance. Postponing a detailed analysis to elsewhere, we make a heuristic estimate for the reduction of the previous Tc, by the charging energy. (author). 30 refs, 8 figs

Shielding synchrotron light sources: Advantages of circular shield walls tunnels

Energy Technology Data Exchange (ETDEWEB)

Kramer, S.L. [Design and Accelerator Operations Consulting, 568 Wintergreen Ct Ridge, NY 11961 (United States); Ghosh, V.J.; Breitfeller, M. [NSLS-II, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2016-08-11

Third generation high brightness light sources are designed to have low emittance and high current beams, which contribute to higher beam loss rates that will be compensated by Top-Off injection. Shielding for these higher loss rates will be critical to protect the projected higher occupancy factors for the users. Top-Off injection requires a full energy injector, which will demand greater consideration of the potential abnormal beam miss-steering and localized losses that could occur. The high energy electron injection beam produce significantly higher neutron component dose to the experimental floor than lower energy injection and ramped operations. High energy neutrons produced in the forward direction from thin target beam losses are a major component of the dose rate outside the shield walls of the tunnel. The convention has been to provide thicker 90° ratchet walls to reduce this dose to the beam line users. We present an alternate circular shield wall design, which naturally and cost effectively increases the path length for this forward radiation in the shield wall and thereby substantially decreasing the dose rate for these beam losses. This shield wall design will greatly reduce the dose rate to the users working near the front end optical components but will challenge the beam line designers to effectively utilize the longer length of beam line penetration in the shield wall. Additional advantages of the circular shield wall tunnel are that it's simpler to construct, allows greater access to the insertion devices and the upstream in tunnel beam line components, as well as reducing the volume of concrete and therefore the cost of the shield wall.

Study and application of high-density concrete in radiation-shielding experiment

International Nuclear Information System (INIS)

Wu Chongming; Ding Dexin; Xiao Xuefu; Wang Shaolin; Lin Xingjun; Shen Yuanyuan

2008-01-01

According to the demand for research and construction project, a series of systematic experiments and studies on shielding γ-ray radiation concrete with the density of 4.60 t/m 3 were made in such aspects as mix ratio design, construction technology, uniformly shielding etc. Such issues as uniformity in the construction and compactness were solved. The ray test method for uniformly shielding concrete was presented and some technical steps for this high-density concrete used in the process of test design or construction were summed up. A series of tests and practical applications show that this technology of mix ratio design and construction is feasible. (authors)

On the superconducting phase diagram of high Tc superconductors

International Nuclear Information System (INIS)

de la Cruz, F.

1990-01-01

The tendency of oxide superconductors to show granularity has been pointed out since the beginning of research on superconductivity in this type of materials. Nevertheless, only very recently the full phase diagram and characteristics of the grains have been determined. In this paper, the authors review and discuss the different critical fields and their relation to the transport of superconducting current. The superconducting response of single crystals of High Tc superconductors is discussed. Special attention is devoted to the behavior of the vortex lattice and, in particular, to the recent discovery of the quenching of H c1 in YBaCuO, several degrees below Tc

High ionization radiation field remote visualization device - shielding requirements

International Nuclear Information System (INIS)

Fernandez, Antonio P. Rodrigues; Omi, Nelson M.; Silveira, Carlos Gaia da; Calvo, Wilson A. Pajero

2011-01-01

The high activity sources manipulation hot-cells use special and very thick leaded glass windows. This window provides a single sight of what is being manipulated inside the hot-cell. The use of surveillance cameras would replace the leaded glass window, provide other sights and show more details of the manipulated pieces, using the zoom capacity. Online distant manipulation may be implemented, too. The limitation is their low ionizing radiation resistance. This low resistance also limited the useful time of robots made to explore or even fix problematic nuclear reactor core, industrial gamma irradiators and high radioactive leaks. This work is a part of the development of a high gamma field remote visualization device using commercial surveillance cameras. These cameras are cheap enough to be discarded after the use for some hours of use in an emergency application, some days or some months in routine applications. A radiation shield can be used but it cannot block the camera sight which is the shield weakness. Estimates of the camera and its electronics resistance may be made knowing each component behavior. This knowledge is also used to determine the optical sensor type and the lens material, too. A better approach will be obtained with the commercial cameras working inside a high gamma field, like the one inside of the IPEN Multipurpose Irradiator. The goal of this work is to establish the radiation shielding needed to extend the camera's useful time to hours, days or months, depending on the application needs. (author)

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.

Tc Generator Development: Up-to-Date Tc Recovery Technologies for Increasing the Effectiveness of Mo Utilisation

Directory of Open Access Journals (Sweden)

Van So Le

2014-01-01

Full Text Available A review on the Mo sources available today and on the Tc generators developed up to date for increasing the effectiveness of Mo utilisation is performed in the format of detailed description of the features and technical performance of the technological groups of the Mo production and Tc recovery. The latest results of the endeavour in this field are also surveyed in regard of the technical solution for overcoming the shortage of Mo supply. The technological topics are grouped and discussed in a way to reflect the similarity in the technological process of each group. The following groups are included in this review which are high specific activity Mo: the current issues of production, the efforts of more effective utilisation, and the high specific activity Mo-based Tc generator and Tc concentration units; low specific activity Mo: the Mo production based on neutron capture and accelerators and the direct production of Tc and the methods of increasing the specific activity of Mo using Szilard-Chalmers reaction and high electric power isotopic separator; up-to-date technologies of Tc recovery from low specific activity Mo: the solvent extraction-based Tc generator, the sublimation methods for Mo/Tc separation, the electrochemical method for Tc recovery, and the column chromatographic methods for Tc recovery. Besides the traditional Tc-generator systems, the integrated Tc generator systems (Tc generator column combined with postelution purification/concentration unit are discussed with the format of process diagram and picture of real generator systems. These systems are the technetium selective sorbent column-based generators, the high Mo-loading capacity column-based integrated Tc generator systems which include the saline-eluted generator systems, and the nonsaline aqueous and organic solvent eluent-eluted generator systems using high Mo-loading capacity molybdategel and recently developed sorbent columns. Tc concentration methods used in the

Radiation shielding lead shield

International Nuclear Information System (INIS)

Dei, Shoichi.

1991-01-01

The present invention concerns lead shields for radiation shielding. Shield boxes are disposed so as to surround a pipeline through which radioactive liquids, mists or like other objects are passed. Flanges are formed to each of the end edges of the shield boxes and the shield boxes are connected to each other by the flanges. Upon installation, empty shield boxes not charged with lead particles and iron plate shields are secured at first at the periphery of the pipeline. Then, lead particles are charged into the shield boxes. This attains a state as if lead plate corresponding to the depth of the box is disposed. Accordingly, operations for installation, dismantling and restoration can be conducted in an empty state with reduced weight to facilitate the operations. (I.S.)

A novel phthalimide derivative, TC11, has preclinical effects on high-risk myeloma cells and osteoclasts.

Directory of Open Access Journals (Sweden)

Maiko Matsushita

Full Text Available Despite the recent advances in the treatment of multiple myeloma (MM, MM patients with high-risk cytogenetic changes such as t(4;14 translocation or deletion of chromosome 17 still have extremely poor prognoses. With the goal of helping these high-risk MM patients, we previously developed a novel phthalimide derivative, TC11. Here we report the further characterization of TC11 including anti-myeloma effects in vitro and in vivo, a pharmacokinetic study in mice, and anti-osteoclastogenic activity. Intraperitoneal injections of TC11 significantly delayed the growth of subcutaneous tumors in human myeloma-bearing SCID mice. Immunohistochemical analyses showed that TC11 induced apoptosis of MM cells in vivo. In the pharmacokinetic analyses, the Cmax was 2.1 μM at 1 h after the injection of TC11, with 1.2 h as the half-life. TC11 significantly inhibited the differentiation and function of tartrate-resistant acid phosphatase (TRAP-positive multinucleated osteoclasts in mouse osteoclast cultures using M-CSF and RANKL. We also revealed that TC11 induced the apoptosis of myeloma cells accompanied by α-tubulin fragmentation. In addition, TC11 and lenalidomide, another phthalimide derivative, directly bound to nucleophosmin 1 (NPM1, whose role in MM is unknown. Thus, through multiple molecular interactions, TC11 is a potentially effective drug for high-risk MM patients with bone lesions. The present results suggest the possibility of the further development of novel thalidomide derivatives by drug designing.

A feasibility study of high-strength Bi-2223 conductor for high-field solenoids

Science.gov (United States)

Godeke, A.; Abraimov, D. V.; Arroyo, E.; Barret, N.; Bird, M. D.; Francis, A.; Jaroszynski, J.; Kurteva, D. V.; Markiewicz, W. D.; Marks, E. L.; Marshall, W. S.; McRae, D. M.; Noyes, P. D.; Pereira, R. C. P.; Viouchkov, Y. L.; Walsh, R. P.; White, J. M.

2017-03-01

We performed a feasibility study on a high-strength Bi{}2-xPb x Sr2Ca2Cu3O{}10-x(Bi-2223) tape conductor for high-field solenoid applications. The investigated conductor, DI-BSCCO Type HT-XX, is a pre-production version of Type HT-NX, which has recently become available from Sumitomo Electric Industries. It is based on their DI-BSCCO Type H tape, but laminated with a high-strength Ni-alloy. We used stress-strain characterizations, single- and double-bend tests, easy- and hard-way bent coil-turns at various radii, straight and helical samples in up to 31.2 T background field, and small 20-turn coils in up to 17 T background field to systematically determine the electro-mechanical limits in magnet-relevant conditions. In longitudinal tensile tests at 77 K, we found critical stress- and strain-levels of 516 MPa and 0.57%, respectively. In three decidedly different experiments we detected an amplification of the allowable strain with a combination of pure bending and Lorentz loading to ≥slant 0.92 % (calculated elastically at the outer tape edge). This significant strain level, and the fact that it is multi-filamentary conductor and available in the reacted and insulated state, makes DI-BSCCO HT-NX highly suitable for very high-field solenoids, for which high current densities and therefore high loads are required to retain manageable magnet dimensions.

Radiological Shielding Design for the Neutron High-Resolution Backscattering Spectrometer EMU at the OPAL Reactor

Directory of Open Access Journals (Sweden)

Ersez Tunay

2017-01-01

Full Text Available The shielding for the neutron high-resolution backscattering spectrometer (EMU located at the OPAL reactor (ANSTO was designed using the Monte Carlo code MCNP 5-1.60. The proposed shielding design has produced compact shielding assemblies, such as the neutron pre-monochromator bunker with sliding cylindrical block shields to accommodate a range of neutron take-off angles, and in the experimental area - shielding of neutron focusing guides, choppers, flight tube, backscattering monochromator, and additional shielding elements inside the Scattering Tank. These shielding assemblies meet safety and engineering requirements and cost constraints. The neutron dose rates around the EMU instrument were reduced to < 0.5 µSv/h and the gamma dose rates to a safe working level of ≤ 3 µSv/h.

Radiological Shielding Design for the Neutron High-Resolution Backscattering Spectrometer EMU at the OPAL Reactor

Science.gov (United States)

Ersez, Tunay; Esposto, Fernando; Souza, Nicolas R. de

2017-09-01

The shielding for the neutron high-resolution backscattering spectrometer (EMU) located at the OPAL reactor (ANSTO) was designed using the Monte Carlo code MCNP 5-1.60. The proposed shielding design has produced compact shielding assemblies, such as the neutron pre-monochromator bunker with sliding cylindrical block shields to accommodate a range of neutron take-off angles, and in the experimental area - shielding of neutron focusing guides, choppers, flight tube, backscattering monochromator, and additional shielding elements inside the Scattering Tank. These shielding assemblies meet safety and engineering requirements and cost constraints. The neutron dose rates around the EMU instrument were reduced to < 0.5 µSv/h and the gamma dose rates to a safe working level of ≤ 3 µSv/h.

Dosimetric perturbations of a lead shield for surface and interstitial high-dose-rate brachytherapy

International Nuclear Information System (INIS)

Candela-Juan, Cristian; Granero, Domingo; Vijande, Javier; Ballester, Facundo; Perez-Calatayud, Jose; Rivard, Mark J

2014-01-01

In surface and interstitial high-dose-rate brachytherapy with either 60 Co, 192 Ir, or 169 Yb sources, some radiosensitive organs near the surface may be exposed to high absorbed doses. This may be reduced by covering the implants with a lead shield on the body surface, which results in dosimetric perturbations. Monte Carlo simulations in Geant4 were performed for the three radionuclides placed at a single dwell position. Four different shield thicknesses (0, 3, 6, and 10 mm) and three different source depths (0, 5, and 10 mm) in water were considered, with the lead shield placed at the phantom surface. Backscatter dose enhancement and transmission data were obtained for the lead shields. Results were corrected to account for a realistic clinical case with multiple dwell positions. The range of the high backscatter dose enhancement in water is 3 mm for 60 Co and 1 mm for both 192 Ir and 169 Yb. Transmission data for 60 Co and 192 Ir are smaller than those reported by Papagiannis et al (2008 Med. Phys. 35 4898–4906) for brachytherapy facility shielding; for 169 Yb, the difference is negligible. In conclusion, the backscatter overdose produced by the lead shield can be avoided by just adding a few millimetres of bolus. Transmission data provided in this work as a function of lead thickness can be used to estimate healthy organ equivalent dose saving. Use of a lead shield is justified. (paper)

Shielding analysis of high level waste water storage facilities using MCNP code

Energy Technology Data Exchange (ETDEWEB)

Yabuta, Naohiro [Mitsubishi Research Inst., Inc., Tokyo (Japan)

2001-01-01

The neutron and gamma-ray transport analysis for the facility as a reprocessing facility with large buildings having thick shielding was made. Radiation shielding analysis consists of a deep transmission calculation for the concrete wall and a skyshine calculation for the space out of the buildings. An efficient analysis with a short running time and high accuracy needs a variance reduction technique suitable for all the calculation regions and structures. In this report, the shielding analysis using MCNP and a discrete ordinate transport code is explained and the idea and procedure of decision of variance reduction parameter is completed. (J.P.N.)

Rapid solidification for preparation of high Tc superconductors

International Nuclear Information System (INIS)

Yavari, A.R.

1988-01-01

High Tc superconducting oxides are prepared in two different ways using rapid solidification: by oxidation of microcrystalline or amorphous tapes obtained by quenching the liquid alloy and via crystallisation of the amorphous oxide obtained by rapid quenching of the oxide melt. This technique is applied for the first time to the BiCaSrCuO family [fr

'99Mo/99mTc Generator Based on High Radionuclidic Pure Zirconium Molybdate Gel

International Nuclear Information System (INIS)

Amin, M.; Mostafa, M.; El-Amir, M.A.; El-Absy, M.A.; Mohamed, O.I.; Farag, A.B.

2014-01-01

99 Mo / 99 mTc radioisotope generator was prepared using in-situ precipitated zirconium molybdate chromatographic column. Zirconium molybdate gel matrix was synthesized by precipitation of neutron activation molybdenum-99 from its solution after variety purification processes to prevent contamination of the 99m Tc eluate with cross-contaminants. Greeter than 82.7 ± 0.4 % of the generated 99m Tc was immediately and reproducible eluted by passing 10 ml 0.9 % NaCl solution through the 1 g zirconium molybdate- 99 Mo column matrix at a flow rate of 0.5 ml / min and room temperature with high chemical, radionuclide ( ≥ 99.9 % 99m Tc) and radiochemical purity ( ≥ 97.7 % % as 99 mTcO 4 - ) with ph value suitable for medical uses.

Development and application of high performance liquid shielding materials

International Nuclear Information System (INIS)

Miura, Toshimasa; Omata, Sadao; Otano, Naoteru; Hirao, Yoshihiro; Kanai, Yasuji

1998-01-01

Development of liquid shielding material with good performance for neutron and γ-ray was investigated. Lead, hydrogen and boron were selected as the elements of shielding materials which were made by the ultraviolet curing method. Good performance shielding materials with about 1 mm width to neutron and gamma ray were produced by mixing lead, boron compound and ultraviolet curing monomer with many hydrogens. The shielding performance was the same as a concrete with two times width. The activation was very small such as 1/10 6 -1/10 8 of the standard concrete. The weight and the external appearance did not charged from room temperature to 100degC. Polyfunctional monomer had good thermal resistance. This shielding material was applied to double bending cylindrical duct and annulus ring duct. The results proved the shielding materials developed had good performance. (S.Y.)

Temperature Dependence of Quasiparticle Spectral Weight and Coherence in High Tc Superconductors

Science.gov (United States)

He, Yang; Zhang, Jessie; Hoffman, Jennifer; Hoffman Lab Team

2014-03-01

Superconductivity arises from the Cooper pairing of quasiparticles on the Fermi surface. Understanding the formation of Cooper pairs is an essential step towards unveiling the mechanism of high Tc superconductivity. We compare scanning tunneling microscope investigations of the temperature dependence of quasiparticle spectral weight and quasiparticle interference in several families of high Tc materials. We calculate the coherent spectral weight related to superconductivity, despite the coexistence of competing orders. The relation between pairing temperature and coherent spectral weight is discussed. We acknowledge support by the New York Community Trust-George Merck Fund.

Oxygen stoichiometry and the high Tc superconducting oxides

International Nuclear Information System (INIS)

Tarascon, J.M.; Bagley, B.G.

1989-01-01

Methods for determining the oxygen content in high Tc materials, such as thermogravimetric analysis and chemical analysis, are discussed. Consideration is given to La-based cuprates, Y-based cuprates, and Bi-based cuprates. Superconducting transition temperatures are analyzed as a function of the Cu(1)-O(4) bond lengths for several different compositions in the Y-based system. 28 references

Evaluation of the shielding integrity of end-shields in PHWR type NPPs

International Nuclear Information System (INIS)

Sah, B.M.L.; Ramamirtham, B.; Kutty, B.S.

1996-01-01

In the new plants (Narora Atomic Power Plants (NAPP) onwards) relatively higher radiation fields exist on the north and south fuelling machine (FM) vault walls of the E1 100m accessible area passages. These fields were first noticed at NAPS-1 and subsequently at NAPS-2 and KAPS-1. Such surveys done at RAPS have indicated that the fields on these walls would come out to be quite low (only 1-2 mR/h) from sources other than that arising from 41 Ar contamination. RAPS/MAPS experience pointed to adequacy of shielding of the FM vault walls and sufficient overall shielding thickness of the end-shields. Further, radiometry tests of end-shields carried out at Kaiga and RAPP 3 and 4 indicated fairly satisfactory and uniform filling of balls. Hence, incomplete filling of water column of the end-shields due to any venting problem was suspected to be one possible reason for the observed high fields in NAPS and Kakrapar Atomic Power Station (KAPS). Since the presence of high radiation fields, both neutron and gamma, is of long-term concern, a special study/measurement of radiation levels on reactor face during high power operation was undertaken. In order to compare the shielding integrity of the older (RAPS/MAPS solid plate type shielding) and newer (NAPS/KAPS steel ball-filled type) end shields, these experiments were done at MAPS-2 and NAPS-2. (author). 2 refs., 2 tabs

Validation of SCALE code package on high performance neutron shields

International Nuclear Information System (INIS)

Bace, M.; Jecmenica, R.; Smuc, T.

1999-01-01

The shielding ability and other properties of new high performance neutron shielding materials from the KRAFTON series have been recently published. A comparison of the published experimental and MCNP results for the two materials of the KRAFTON series, with our own calculations has been done. Two control modules of the SCALE-4.4 code system have been used, one of them based on one dimensional radiation transport analysis (SAS1) and other based on the three dimensional Monte Carlo method (SAS3). The comparison of the calculated neutron dose equivalent rates shows a good agreement between experimental and calculated results for the KRAFTON-N2 material.. Our results indicate that the N2-M-N2 sandwich type is approximately 10% inferior as neutron shield to the KRAFTON-N2 material. All values of neutron dose equivalent obtained by SAS1 are approximately 25% lower in comparison with the SAS3 results, which indicates proportions of discrepancies introduced by one-dimensional geometry approximation.(author)

High performance inboard shield design for the compact TIBER-II test reactor: Appendix A-2

International Nuclear Information System (INIS)

El-Guebaly, L.A.; Sviatoslavsky, I.N.

1987-01-01

The compactness of the TIBER-II reactor has placed a premium on the design of a high performance inboard shield to protect the inner legs of the toroidal field (TF) coils. The available space for shield is constrained to 48 cm and the use of tungsten is mandatory to protect the magnet against the 1.53 MW/m 2 neutron wall loading. The primary requirement for the shield is to limit the fast neutron fluence to 10 19 n/cm 2 . In an optimization study, the performance of various candidate materials for protecting the magnet was examined. The optimum shield consists of a 40 cm thick W layer, followed by an 8 cm thick H 2 O/LiNO 3 layer. The mechanical design of the shield calls for tungsten blocks within SS stiffened panels. All the coolant channels are vertical with more of them in the front where there is a high heat load. The coolant pressure is 0.2 MPa and the maximum structural surface temperature is 0 C. The effects of the detailed mechanical design of the shield and the assembly gaps between the shield sectors on the damage in the magnet were analyzed and peaking factors of ∼2 were found at the hot spots. 2 refs., 6 figs., 2 tabs

Linear and nonlinear flux dynamics in multilayered Bi2Sr2CaCu2Ox single crystals

DEFF Research Database (Denmark)

Pedersen, Niels Falsig; Filatrella, G.

2002-01-01

For an anisotropic, multilayered superconductor of the BSCCO type or a low Tc Josephson stack, the linear plasma resonances are derived theoretically using the inductive coupling model. The eigenmodes of these plasma oscillations are discussed. It is shown that symmetries from the plasma dispersion...

Survivor shielding. Part C. Improvements in terrain shielding

International Nuclear Information System (INIS)

Egbert, Stephen D.; Kaul, Dean C.; Roberts, James A.; Kerr, George D.

2005-01-01

A number of atomic-bomb survivors were affected by shielding provided by terrain features. These terrain features can be a small hill, affecting one or two houses, or a high mountain that shields large neighborhoods. In the survivor dosimetry system, terrain shielding can be described by a transmission factor (TF), which is the ratio between the dose with and without the terrain present. The terrain TF typically ranges between 0.1 and 1.0. After DS86 was implemented at RERF, the terrain shielding categories were examined and found to either have a bias or an excessive uncertainty that could readily be removed. In 1989, an improvement in the terrain model was implemented at RERF in the revised DS86 code, but the documentation was not published. It is now presented in this section. The solution to the terrain shielding in front of a house is described in this section. The problem of terrain shielding of survivors behind Hijiyama mountain at Hiroshima and Konpirasan mountain at Nagasaki has also been recognized, and a solution to this problem has been included in DS02. (author)

Characterization of sup(99m)Tc/sup(99)Tc-hydroxycarboxylic acid chelates by high voltage electrophoresis without supporting material

International Nuclear Information System (INIS)

Hoffmann, I.; Muenze, R.; Dreyer, I.; Dreyer, R.

1982-01-01

Ion mobilities of different sup(99m)Tc- and 99 Tc chelates prepared by reduction of pertechnetate by Sn(II) in the presence of citric, malic, tartaric, gluconic, and α-hydroxyisobutyric acid as ligands have been measured by means of electrophoresis without supporting material. All the chelates investigated proved to be anions in the pH range of 2-7. Both the Tc(V)- and Tc(IV) compounds with the same ligand including the sup(99m)Tc preparation show identical ion mobilities and dissociation characteristics. (author)

Soil biological shield exposed to high energy neutrons; Zemlja kao bioloski stit od neutrona visokih energija

Energy Technology Data Exchange (ETDEWEB)

Simovic, R; Marinkovic, N [Institute of nuclear sciences Vinca, Belgrade (Yugoslavia)

1993-04-15

Shielding efficiency of soil biological shield exposed to high energy neutrons was investigated. Dose rate equivalents for neutrons, secondary gamma and gamma radiation were computed on the surface of soil slabs having different thicknesses. Yields of primary and secondary nuclear radiation in the total dose were evaluated. Influence of the incident neutron spectrum, water content and chemical composition of the material on its shielding efficiency was examined. It was found that the soil density and the water content determine the quality of biological shield, the influence of other factors being less important. Comparison of shielding efficiencies for soil with sand, brick and ordinary concrete shields was done.

Feshbach shape resonance for high Tc pairing in superlattices of quantum stripes and quantum wells

Directory of Open Access Journals (Sweden)

A Bianconi

2006-09-01

Full Text Available   The Feshbach shape resonances in the interband pairing in superconducting superlattices of quantum wells or quantum stripes is shown to provide the mechanism for high Tc superconductivity. This mechanism provides the Tc amplification driven by the architecture of material: superlattices of quantum wells (intercalated graphite or diborides and superlattices of quantum stripes (doped high Tc cuprate perovskites where the chemical potential is tuned to a Van Hove-Lifshitz singularity (vHs in the electronic energy spectrum of the superlattice associated with the change of the Fermi surface dimensionality in one of the subbands.

Electronic components with yttrium- and bismuth-based high-Tc superconductors

International Nuclear Information System (INIS)

Daginnus, M.; Guettler, B.

1992-01-01

This project investigates the fabrication of microwave components by use of high-Tc superconductors. Detailed descriptions are given of the manufacturing and use of active Y-Ba-Cu-O components. The surface resistance of thin films used in high-quality passive microwave components such as resonators and filters is measured and optimized. (orig./MM) [de

High field septum magnet using a superconducting shield for the Future Circular Collider

Directory of Open Access Journals (Sweden)

Dániel Barna

2017-04-01

Full Text Available A zero-field cooled superconducting shield is proposed to realize a high-field (3–4 T septum magnet for the Future Circular Collider hadron-hadron (FCC-hh ring. Three planned prototypes using different materials and technical solutions are presented, which will be used to evaluate the feasibility of this idea as a part of the FCC study. The numerical simulation methods are described to calculate the field patterns around such a shield. A specific excitation current configuration is presented that maintains a fairly homogeneous field outside of a rectangular shield in a wide range of field levels from 0 to 3 Tesla. It is shown that a massless septum configuration (with an opening in the shield is also possible and gives satisfactory field quality with realistic superconducting material properties.

High field septum magnet using a superconducting shield for the Future Circular Collider

CERN Document Server

AUTHOR|(CDS)2069375

2017-01-01

A zero-field cooled superconducting shield is proposed to realize a high-field (3–4 T) septum magnet for the Future Circular Collider hadron-hadron (FCC-hh) ring. Three planned prototypes using different materials and technical solutions are presented, which will be used to evaluate the feasibility of this idea as a part of the FCC study. The numerical simulation methods are described to calculate the field patterns around such a shield. A specific excitation current configuration is presented that maintains a fairly homogeneous field outside of a rectangular shield in a wide range of field levels from 0 to 3 Tesla. It is shown that a massless septum configuration (with an opening in the shield) is also possible and gives satisfactory field quality with realistic superconducting material properties.

Highly ductile UV-shielding polymer composites with boron nitride nanospheres as fillers.

Science.gov (United States)

Fu, Yuqiao; Huang, Yan; Meng, Wenjun; Wang, Zifeng; Bando, Yoshio; Golberg, Dmitri; Tang, Chengchun; Zhi, Chunyi

2015-03-20

Polymer composites with enhanced mechanical, thermal or optical performance usually suffer from poor ductility induced by confined mobility of polymer chains. Herein, highly ductile UV-shielding polymer composites are successfully fabricated. Boron nitride (BN) materials, with a wide band gap of around ∼6.0 eV, are used as fillers to achieve the remarkably improved UV-shielding performance of a polymer matrix. In addition, it is found that spherical morphology BN as a filler can keep the excellent ductility of the composites. For a comparison, it is demonstrated that traditional fillers, including conventional BN powders can achieve the similar UV-shielding performance but dramatically decrease the composite ductility. The mechanism behind this phenomenon is believed to be lubricant effects of BN nanospheres for sliding of polymer chains, which is in consistent with the thermal analyses. This study provides a new design to fabricate UV-shielding composite films with well-preserved ductility.

AC losses in high Tc superconductors

International Nuclear Information System (INIS)

Campbell, A.M.

1998-01-01

Full text: Although in principle the AC losses in high Tc superconductors can be calculated from the critical current density, a number of complications make this difficult. The Jc is very field dependent, there are intergranular and intragranular critical currents, the material is anisotropic and there is usually a large demagnetising factor. Care must be taken in interpreting electrical measurements since the voltage depends on the position of the contacts. In spite of these complications the simple theory of Norris has proved surprisingly successful and arguments will be presented as to why this is the case. Results on a range of tapes will be compared with theory and numerical methods for predicting losses discussed. Finally a theory for coupling losses will be given for a composite conductor with high resistance barriers round the filaments

Non-combustible nuclear radiation shields with high hydrogen content

International Nuclear Information System (INIS)

Hall, W.C.; Peterson, J.M.

1978-01-01

The invention relates to compositions, methods of production, and uses of non-combustible nuclear radiation shields, with particular emphasis on those containing a high concentration of hydrogen atoms, especially effective for moderating neutron energy by elastic scatter, dispersed as a discontinuous phase in a continuous phase of a fire resistant matrix

Simulation of high field induced first-order phase transition in Bi2Sr2CaCu2O8

International Nuclear Information System (INIS)

Viana, Leonardo P.; Raposo, E.P.; Coutinho-Filho, M.D.

2004-01-01

The occurrence and nature of first-order transitions (FOT) in Bi 2 Sr 2 CaCu 2 O 8 (BSCCO) are still open issues, although results from a number of experiments do support a FOT both at low and high fields. We present a FOT obtained via Monte Carlo simulations using the Lawrence-Doniach model for layered superconductors, focusing on a clean 3D sample of BSCCO, with dc field applied perpendicular to the CuO 2 planes. Our results confirm Nelson's predictions for the random-walk-like diffusion of melted lines, contrarily to some recent suggestions. Further results for the z-dependent density-density correlation function indicate that in the high field regime the CuO 2 planes decouple along with line melting, in agreement with experimental observations in BSCCO

Quantum Monte Carlo simulations for high-Tc superconductors

International Nuclear Information System (INIS)

Muramatsu, A.; Dopf, G.; Wagner, J.; Dieterich, P.; Hanke, W.

1992-01-01

Quantum Monte Carlo simulations for a multi-band model of high-Tc superconductors are reviewed with special emphasis on the comparison of different observabels with experiments. It is shown that a give parameter set of the three-band Hubbard model leads to a consistent description of normal-state propteries as well as pairing correlation function for the copper-oxide superconductors as a function of doping and temperature. (orig.)

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

Nanoscale insight of high piezoelectricity in high-TC PMN-PH-PT ceramics

Science.gov (United States)

Zhu, Rongfeng; Zhang, Qihui; Fang, Bijun; Zhang, Shuai; Zhao, Xiangyong; Ding, Jianning

2018-03-01

The piezoelectric properties of the high-Curie temperature (high-TC) 0.15Pb(Mg1/3Nb2/3)O3-0.38PbHfO3-0.47PbTiO3 (0.15PMN-0.38PH-0.47PT) ceramics prepared by three different methods were compared. The 0.15PMN-0.38PH-0.47PT ceramics synthesized by the partial oxalate route exhibit the optimum properties, in which d33* = 845.3 pm/V, d33 = 456.2 pC/N, Kp = 67.2%, and TC = 291 °C. The nanoscale origin of the high piezoelectric response of the 0.15PMN-0.38PH-0.47PT ceramics was investigated by piezoresponse force microscopy (PFM) using the ceramics synthesized by the partial oxalate route. Large quantities of fine stripe submicron ferroelectric domains are observed, which form large island domains. In order to give further insights into the piezoelectric properties of the 0.15PMN-0.38PH-0.47PT ceramics from a microscopic point of view, the local poling experiments and local switching spectroscopy piezoresponse force microscopy (SS-PFM) were investigated, from which the local converse piezoelectric coefficient d33*(l) is calculated as 220 pm/V.

Critical currents and superconductivity ferromagnetism coexistence in high-Tc oxides

CERN Document Server

Khene, Samir

2016-01-01

The book comprises six chapters which deal with the critical currents and the ferromagnetism-superconductivity coexistence in high-Tc oxides. It begins by gathering key data for superconducting state and the fundamental properties of the conventional superconductors, followed by a recap of the basic theories of superconductivity. It then discusses the differences introduced by the structural anisotropy on the Ginzburg-Landau approach and the Lawrence-Doniach model before addressing the dynamics of vortices and the ferromagnetism-superconductivity coexistence in high-Tc oxides, and provides an outline of the pinning phenomena of vortices in these materials, in particular the pinning of vortices by the spins. It elucidates the methods to improve the properties of superconducting materials for industrial applications. This optimization aims at obtaining critical temperatures and densities of critical currents at the maximum level possible. Whereas the primary objective is the basic mechanisms pushing the superco...

Critical current of high Tc superconducting Bi223/Ag tapes

NARCIS (Netherlands)

Huang, Y.; ten Haken, Bernard; ten Kate, Herman H.J.

1998-01-01

The magnetic field dependence of the critical current of various high Tc superconducting Bi2223/Ag tapes indicates that the transport current is carried through two paths: one is through weakly-linked grain boundaries (Josephson junctions); another is through well-connected grains. The critical

Radiation Build-Up In Shielding Of Low Activity High Energia Gamma Source

International Nuclear Information System (INIS)

Helfi-Yuliati; Mukhlis-Akhadi

2003-01-01

Research to observe radiation build-up factor (b) in aluminium (Al), iron (Fe) and lead (Pb) for shielding of gamma radiation of high energy from 137 cs (E γ : 662 keV) source and 60 Co (E γ : 1332 keV) of low activity sources has been carried out. Al with Z =13 represent metal of low atomic number, Fe with Z =26 represent metal of medium atomic number, and Pb with Z = 82 represent metal of high atomic number. Low activity source in this research is source which if its dose rate decrease to 3 % of its initial dose rate became safe for the workers. Research was conducted by counting of radiation intensity behind shielding with its thickness vary from 1 to 5 times of half value thickness (HVT). NaI(TI) detector which connected to multi channel analyzer (MCA) was used for the counting. Calculation result show that all of b value are close to 1 (b ∼ 1) for all kinds of metals. No radiation build-up factor is required in estimating the shielding thickness from several kinds of metals for low activity of high energy gamma source. (author)

Enhanced microwave shielding and mechanical properties of high loading MWCNT–epoxy composites

International Nuclear Information System (INIS)

Singh, B. P.; Prasanta; Choudhary, Veena; Saini, Parveen; Pande, Shailaja; Singh, V. N.; Mathur, R. B.

2013-01-01

Dispersion of high loading of carbon nanotubes (CNTs) in epoxy resin is a challenging task for the development of efficient and thin electromagnetic interference (EMI) shielding materials. Up to 20 wt% of multiwalled carbon nanotubes (MWCNTs) loading in the composite was achieved by forming CNT prepreg in the epoxy resin as a first step. These prepreg laminates were then compression molded to form composites which resulted in EMI shielding effectiveness of −19 dB for 0.35 mm thick film and −60 dB at for 1.75 mm thick composites in the X-band (8.2–12.4 GHz). One of the reasons for such high shielding is attributed to the high electrical conductivity of the order of 9 S cm −1 achieved in these composites which is at least an order of magnitude higher than previously reported results at this loading. In addition, an improvement of 40 % in the tensile strength over the neat resin value is observed. Thermal conductivity of the MWCNTs–epoxy composite reached 2.18 W/mK as compared to only 0.14 W/mK for cured epoxy.

Enhanced microwave shielding and mechanical properties of high loading MWCNT-epoxy composites

Science.gov (United States)

Singh, B. P.; Prasanta; Choudhary, Veena; Saini, Parveen; Pande, Shailaja; Singh, V. N.; Mathur, R. B.

2013-04-01

Dispersion of high loading of carbon nanotubes (CNTs) in epoxy resin is a challenging task for the development of efficient and thin electromagnetic interference (EMI) shielding materials. Up to 20 wt% of multiwalled carbon nanotubes (MWCNTs) loading in the composite was achieved by forming CNT prepreg in the epoxy resin as a first step. These prepreg laminates were then compression molded to form composites which resulted in EMI shielding effectiveness of -19 dB for 0.35 mm thick film and -60 dB at for 1.75 mm thick composites in the X-band (8.2-12.4 GHz). One of the reasons for such high shielding is attributed to the high electrical conductivity of the order of 9 S cm-1 achieved in these composites which is at least an order of magnitude higher than previously reported results at this loading. In addition, an improvement of 40 % in the tensile strength over the neat resin value is observed. Thermal conductivity of the MWCNTs-epoxy composite reached 2.18 W/mK as compared to only 0.14 W/mK for cured epoxy.

Impurity scattering effect on charge transport in high-Tc cuprate junctions

International Nuclear Information System (INIS)

Tanaka, Y.; Asano, Y.; Kashiwaya, S.

2004-01-01

It is known that the zero-bias conductance peak (ZBCP) is expected in tunneling spectra of normal-metal/high-Tc cuprate junctions because of the formation of the midgap Andreev resonant states (MARS) at junction interfaces. In the present review, we report the recent theoretical study of impurity scattering effects on the tunneling spectroscopy. In the former part of the present paper, we discuss impurity effects in normal metal. We calculate tunneling conductance for diffusive normal metal (DN)/high Tc cuprate junctions based on the Keldysh Green's function technique. Besides the ZBCP due to the MARS, we can expect ZBCP caused by the different origin, i.e., the coherent Andreev reflection (CAR) assisted by the proximity effect in DN. Their relative importance depends on the angle a between the interface normal and the crystal axis of high-Tc superconductors. At α = 0, we find the ZBCP by the CAR for low transparent junctions with small Thouless energies in DN; this is similar to the case of diffusive normal metal/insulator/s-wave superconductor junctions. Under increase of α from zero to π/4, the contribution of MARS to ZBCP becomes more prominent and the effect of the CAR is gradually suppressed. Such complex spectral features would be observable in conductance spectra of high-Tc junctions at very low temperatures. In the latter part of our paper, we study impurity effects in superconductors. We consider impurities near the junction interface on the superconductor side. The conductance is calculated from the Andreev and the normal reflection coefficients which are estimated by using the single-site approximation in an analytic calculation and by the recursive Green function method in a numerical simulation. We find splitting of the ZBCP in the presence of the time reversal symmetry. Thus the zero-field splitting of ZBCP in the experiment does not perfectly prove an existence of broken time reversal symmetry state

High-performance heavy concrete as a multi-purpose shield

International Nuclear Information System (INIS)

Mortazavi, S. M. J.; Mosleh-Shirazi, M. A.; Roshan-Shomal, P.; Raadpey, N.; Baradaran-Ghahfarokhi, M.

2010-01-01

Concrete has long been used as a shield against high-energy photons and neutrons. In this study, colemanite and galena minerals (CoGa) were used for the production of an economical high-performance heavy concrete. To measure the gamma radiation attenuation of the CoGa concrete samples, they were exposed to a narrow beam of gamma rays emitted from a 60 Co radiotherapy unit. An Am-Be neutron source was used for assessing the shielding properties of the samples against neutrons. The compression strengths of both types of concrete mixes (CoGa and reference concrete) were investigated. The range of the densities of the heavy concrete samples was 4100-4650 kg m -3 , whereas it was 2300-2600 kg m -3 in the ordinary concrete reference samples. The half-value layer of the CoGa concrete samples for 60 Co gamma rays was 2.49 cm; much less than that of ordinary concrete (6.0 cm). Moreover, CoGa concrete samples had a 10% greater neutron absorption compared with reference concrete. (authors)

Comparison between high-resolution computed tomography and 99mTc-technegas SPECT pulmonary emphysema

International Nuclear Information System (INIS)

Nakano, Satoru; Satoh, Katashi; Takahashi, Kazue

1996-01-01

Scintigraphy with 99m Tc-technegas was recently introduced for clinical imaging of lung ventilation. This method has been found to be useful in emergencies, to be more suitable for single photon emission computed tomography (SPECT) than other agents used in ventilation scintigraphy, and could reveal abnormalities in ventilation more easily than high resolution computed tomography (HRCT) in pulmonary emphysema. We compared 99m Tc-technegas SPECT with HRCT in six regions: the right upper, middle, and lower lobes, the left upper lobe, the lingula, and the left lower lobe, in 15 patients with pulmonary emphysema. Patients with centrilobular emphysema tended to show stronger changes in upper lobes than in lower lobes on both 99m Tc-technegas SPECT and HRCT. Some regions showed no change on HRCT but various changes on 99m Tc-SPECT. Patients with panlobular emphysema showed severe changes on 99m Tc-SPECT in lower lung fields in which well-demarcated areas of low attenuation were not seen on HRCT. We conclude that 99m Tc-SPECT is useful for detecting early changes and panlobular changes in pulmonary emphysema. (author)

Infinite slab-shield dose calculations

International Nuclear Information System (INIS)

Russell, G.J.

1989-01-01

I calculated neutron and gamma-ray equivalent doses leaking through a variety of infinite (laminate) slab-shields. In the shield computations, I used, as the incident neutron spectrum, the leakage spectrum (<20 MeV) calculated for the LANSCE tungsten production target at 90 degree to the target axis. The shield thickness was fixed at 60 cm. The results of the shield calculations show a minimum in the total leakage equivalent dose if the shield is 40-45 cm of iron followed by 20-15 cm of borated (5% B) polyethylene. High-performance shields can be attained by using multiple laminations. The calculated dose at the shield surface is very dependent on shield material. 4 refs., 4 figs., 1 tab

The biological shield of a high-intensity spallation source: a monte Carlo design study

International Nuclear Information System (INIS)

Koprivnikar, I.; Schachinger, E.

2004-01-01

The design of high-intensity spallation sources requires the best possible estimates for the biological shield. The applicability of three-dimensional Monte Carlo simulation in the design of the biological shield of a spallation source will be discussed. In order to achieve reasonable computing times along with acceptable accuracy, biasing techniques are to be employed and it was the main purpose of this work to develop a strategy for an effective Monte Carlo simulation in shielding design. The most prominent MC computer codes, namely MCNPX and FLUKA99, have been applied to the same model spallation source (the European Spallation Source) and on the basis of the derived strategies, the design and characteristics of the target station shield are discussed. It is also the purpose of the paper to demonstrate the application of the developed strategy for the design of beam lines with their shielding using as an example the target-moderator-reflector complex of the ESS as the primary particle source. (author)

Concrete shielding for nuclear ship 'Mutsu'

International Nuclear Information System (INIS)

Nagase, Tetsuo; Saito, Tetsuo

1983-01-01

The repair works of the shielding for the nuclear ship ''Mutsu'' were completed in August, 1982. For the primary shielding, serpentine concrete was adopted as it contains a large quantity of water required for neutron shielding, and in the secondary shielding at the upper part of the reactor containment vessel, the original shielding was abolished, and the heavy concrete (high water content, high density concrete) which is effective for neutron and gamma-ray shielding was newly adopted. In this report, the design and construction using these shielding concrete are outlined. In September, 1974, Mutsu caused radiation leak during the test, and the cause was found to be the fast neutrons streaming through a gap between the reactor pressure vessel and the primary shielding. The repair works were carried out in the Sasebo Shipyard. The outline of the repair works of the shielding is described. The design condition for the shielding, the design standard for the radiation dose outside and inside the ship, the method of shielding analysis and the performance required for shielding concrete are reported. The selection of materials, the method of construction and mixing ratio, the evaluation of the soundness and properties of concrete, and the works of placing the shielding concrete are outlined. (Kako, I.)

Critical Current Test of Liquid Hydrogen Cooled HTC Superconductors under External Magnetic Field

OpenAIRE

Shirai, Yasuyuki; Shiotsu, Masahiro; Tatsumoto, Hideki; Kobayashi, Hiroaki; Naruo, Yoshihiro; Nonaka, Satoshi; Inatani, Yoshifumi

2016-01-01

High-Tc (HTC) superconductors including MgB2 will show excellent properties under temperature of Liquid Hydrogen (LH2:20K), which has large latent heat and low viscosity coefficient. In order to design and fabricate the LH2 cooled superconducting energy devices, we must clear the cooling property of LH2 for superconductors, the cooling system and safety design of LH2 cooled superconducting devices and electro-magnetic property evaluation of superconductors (BSCCO, REBCO and MgB2) and their ma...

Experimental Investigation of Multi-layer Insulation Effect on Damage of Stuffed Shield by High-velocity Impact

Directory of Open Access Journals (Sweden)

GUAN Gong-shun

2016-09-01

Full Text Available The stuffed shield with multi-layer insulation(MLI was designed by improving on Al Whipple shield, and a series of high-velocity impact tests were practiced with a two-stage light gas gun facility at vacuum environment. The damage model of the stuffed shield with different MLI location by Al-sphere projectile impacting was obtained. The effect of MLI on damage of the stuffed shield by high-velocity impact was studied. The results indicate when the MLI is located at front side of the first Al-plate, the protection performance of the stuffed shield is improved with the larger perforation diameter of the first Al-plate and more impact kinetic energy dissipation of the projectile. When MLI is arranged at back side of the first Al-plate, the expansion of the secondary debris cloud from projectile impacting the first Al-plate is restrained, it is not good to improve the protection performance of the stuffed shield. When MLI is arranged at front side of the stuffed wall, the perforation size of the stuffed wall increases; when MLI is arranged at front side of the rear wall, the distribution range of crater on the rear wall decreases.

Field dependence of the current density of superconductors at high temperatures

International Nuclear Information System (INIS)

Hiergeist, R.; Hergt, R.; Erb, A.; Kummeth, P.; Winzer, K.

1993-01-01

An essential drawback of the high-T c superconductors (HTS) with respect to technical applications at liquid nitrogen temperature is the large degradation of their pinning properties in magnetic fields. For the field dependence of the volume pinning force often a high field tail due to thermally activated flux flow is observed. An exponential decay of the irreversible magnetization with increasing field was reported in the case of sintered material (YBCO) for the intergranular part of the magnetization while a power law decay was found for the intragranular part. Song et al. observed an exponential field dependence of the critical current density for proton-irradiated material which before irradiation showed a power law decay. Gladun et al. found an exponential decay for BSCCO-2223 tapes. The high field behaviour of BSCCO was shown to be governed by thermally activated flux creep with a logarithmic pinning barrier, which may result in an exponential decrease of the current with the external magnetic field, as argued recently by Ries et al. We will show in the present paper that the different HTS substance classes (YBCO, BSCCO, TBCCO) behave qualitatively in a similar way. (orig.)

A study of gamma shielding

International Nuclear Information System (INIS)

Roogtanakait, N.

1981-01-01

Gamma rays have high penetration power and its attenuation depends upon the thickness and the attenuation coefficient of the shield, so it is necessary to use the high density shield to attenuate the gamma rays. Heavy concrete is considered to be used for high radiation laboratory and the testing of the shielding ability and compressibility of various types of heavy concrete composed of baryte, hematite, ilmenite and galena is carried out. The results of this study show that baryte-ilmenite concrete is the most suitable for high radiation laboratory in Thailand

Radiation shielding

International Nuclear Information System (INIS)

Aitken, D.

1979-01-01

Shields for equipment in which ionising radiation is associated with high electrical gradients, for example X-ray tubes and particle accelerators, incorporate a radiation-absorbing metal, as such or as a compound, and are electrically non-conducting and can be placed in the high electrical gradient region of the equipment. Substances disclosed include dispersions of lead, tungsten, uranium or oxides of these in acrylics polyesters, PVC, ABS, polyamides, PTFE, epoxy resins, glass or ceramics. The material used may constitute an evacuable enclosure of the equipment or may be an external shield thereof. (U.K.)

Primary shield displacement and bowing

International Nuclear Information System (INIS)

Scott, K.V.

1978-01-01

The reactor primary shield is constructed of high density concrete and surrounds the reactor core. The inlet, outlet and side primary shields were constructed in-place using 2.54 cm (1 in) thick steel plates as the forms. The plates remained as an integral part of the shields. The elongation of the pressure tubes due to thermal expansion and pressurization is not moving through the inlet nozzle hardware as designed but is accommodated by outward displacement and bowing of the inlet and outlet shields. Excessive distortion of the shields may result in gas seal failures, intolerable helium gas leaks, increased argon-41 emissions, and shield cooling tube failures. The shield surveillance and testing results are presented

Electronic Instability at High Flux-Flow Velocities in High-Tc Superconducting Films

DEFF Research Database (Denmark)

Doettinger, S. G.; Huebener, R. P.; Gerdemann, R.

1994-01-01

At high flux-flow velocities in type-II superconductors the nonequilibrium distribution of the quasiparticles leads to an electronic instability and an aburpt switching into a state with higher electric resistivity, as predicted by Larkin and Ovchinnikow (LO). We report the first obervation...... of this effect in a high-temperature superconductor, namely in epitaxial c-axis oriented films of YBa(2)Cu3O(7)-(delta). Using the LO therory, we have extracted from out results the inelastic quasiparticle scattering rare tau(in)(-1), which strongly decreases with decreasing temperature below T-c...

Practical high-density shielding materials for medical linear accelerator rooms

International Nuclear Information System (INIS)

Barish, R.J.

1990-01-01

High-energy linear accelerators are replacing lower energy units in radiation therapy centers. Radiation protection requirements necessitate expensive reconstruction of existing treatment rooms to accommodate these new machines. We describe two shielding materials: one made by embedding small pieces of scrap steel in cement, and the other made with cast iron in cement. Both materials produce high-density barriers at low cost using standard construction methods

Magnetic shield effect simulation of superconducting film shield covering directly coupled HTS dc-SQUID magnetometer

International Nuclear Information System (INIS)

Terauchi, N.; Noguchi, S.; Igarashi, H.

2011-01-01

A superconducting film shield over a SQUID ring improves the robustness of the SQUID with respect to magnetic noise. Supercurrent in the SQUID magnetometer and the superconducting film shield were simulated. The superconducting film shield reduces the influence of the external magnetic field on the SQUID ring. An HTS SQUID is a high sensitive magnetic sensor. In recent years, the HTS SQUID is widely used in various applications. In some applications, high robustness with respect to magnetic noise is required to realize stable operation at outside of a magnetic shielding room. The target of this paper is a directly coupled HTS dc-SQUID magnetometer. To enhance the robustness of the SQUID magnetometer, use of a superconducting thin film shield has been proposed. The magnetic field directly penetrating the SQUID ring causes the change of the critical current of Josephson junction, and then the SQUID magnetometer transitions into inoperative state. In order to confirm the magnetic shield effect of the superconducting film shield, electromagnetic field simulation with 3D edge finite element method was performed. To simulate the high temperature superconductor, E-J characteristics and c-axis anisotropy are considered. To evaluate the effect of the superconducting film shield, an external magnetic field which is supposed to be a magnetic noise is applied. From the simulation results, the time transition of the magnetic flux penetrating the SQUID ring is investigated and the effect of the superconducting film shield is confirmed. The amplitude of the magnetic flux penetrating the SQUID ring can be reduced to about one-sixth since the superconducting film shield prevents the magnetic noise from directly penetrating the SQUID ring.

Neutron shielding properties of a borated high-density glass

Directory of Open Access Journals (Sweden)

Saeed Aly Abdallah

2017-01-01

Full Text Available The neutron shielding properties of a borated high density glass system was characterized experimentally. The total removal macroscopic cross-section of fast neutrons, slow neutrons as well as the linear attenuation coefficient of total gamma rays, primary in addition to secondary, were measured experimentally under good geometric condition to characterize the attenuation properties of (75-x B2O3-1Li2O-5MgO-5ZnO-14Na2O-xBaO glassy system. Slabs of different thicknesses from the investigated glass system were exposed to a collimated beam of neutrons emitted from 252Cf and 241Am-Be neutron sources in order to measure the attenuation properties of fast and slow neutrons as well as total gamma rays. Results confirmed that barium borate glass was suitable for practical use in the field of radiation shielding.

Determination of Tc-99 in radioactive wastes; Determinacion de Tc-99 en desechos radiactivos

Energy Technology Data Exchange (ETDEWEB)

Rivera S, A. A.

2015-07-01

Tc-99 is a fission product and one of the most important radionuclides from the view point of safety assessment for the disposal of radioactive waste because of its long half-life (2.1 x 10{sup 5} years) and high mobility in soil-water systems, if this is released into the environment in significant quantities can concentrate on plants and animals. Tc-99 is a pure beta emitter with a maximum energy of 292 KeV, so their quantification imposes destructive methods to be analyzed by liquid scintillation. Therefore the quantification of Tc-99 in ion exchange resins requires of the mineralization of these and separation of Tc-99 of other radioisotopes present in the resin. Therefore the object of this thesis is to develop a quantification method of Tc-99 content in spent exchange resins. So in order to track the behavior of technetium during digestion exchange resins and radiochemical separation, given its high volatility, in this work the {sup 99m}Tc is used. To determine the degree of mineralization of the resins, an analysis was performed by chromatography. Subsequently the method used to determine the percentage of {sup 99m}Tc aerosolized during mineralization of resin is described. After the method for the radiochemical separation of {sup 99m}Tc is presented by liquid-liquid extraction using crown ether as extractant; for this testing was performed by varying the molarity of the extractant, the ratio of solvent extractant, type of digestion of the resin and the presence of Sr-85, in order to study the behavior of {sup 99m}Tc in the presence of this radioisotope. Finally, a track beta spectra of a sample of {sup 99m}Tc eluted from a generator {sup 99}Mo/{sup 99m}Tc function of time was performed. (Author)

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...

The disordered Bose condensate in two dimensions: application to high-Tc superconductors

International Nuclear Information System (INIS)

Gold, A.

1992-01-01

We calculate the dynamical conductivity for a weakly disordered Bose condensate in two dimensions. The disorder is due to neutral impurities. We compare the asymptotic laws (for small and large frequencies) for neutral impurities with the ones for charged impurities. Universal functions for the dynamical transport properties are derived. The plasmon density of states shows a linear increase with energy for intermediate energies and a peak structure at larger energies. Our theoretical results are compared with experimental results (far-infrared, electron-energy-loss and Raman spectroscopy) found in the high-Tc superconductor YBa 2 Cu 3 O 7-δ . The occurrence of a quasi-gap in a disordered Bose condensate is described and discussed in connection with experiments on high-Tc superconductors. (orig.)

Accelerator shielding benchmark problems

International Nuclear Information System (INIS)

Hirayama, H.; Ban, S.; Nakamura, T.

1993-01-01

Accelerator shielding benchmark problems prepared by Working Group of Accelerator Shielding in the Research Committee on Radiation Behavior in the Atomic Energy Society of Japan were compiled by Radiation Safety Control Center of National Laboratory for High Energy Physics. Twenty-five accelerator shielding benchmark problems are presented for evaluating the calculational algorithm, the accuracy of computer codes and the nuclear data used in codes. (author)

Radiation shielding cloth

International Nuclear Information System (INIS)

Ijiri, Yasuo; Fujinuma, Tadashi; Tamura, Shoji.

1989-01-01

Radiation shielding cloth having radiation shielding layers comprising a composition of inorganic powder of high specific gravity and rubber are excellentin flexibility and comfortable to put on. However, since they are heavy in the weight, operators are tired upon putting them for a long time. In view of the above, the radiation ray shielding layers are prepared by calendering sheets obtained by preliminary molding of the composition to set the variation of the thickness within a range of +15% to -0% of prescribed thickness. Since the composition of inorganic powder at high specific gravity and rubber used for radiation ray shielding comprises a great amount of inorganic powder at high specific gravity blended therein, it is generally poor in fabricability. Therefor, it is difficult to attain fine control for the sheet thickness by merely molding a composition block at once. Then, the composition is at first preliminarily molded into a sheet-like shape which is somewhat thickener than the final thickness and then finished by calendering, by which the thickness can be reduced in average as compared with conventional products while keeping the prescribed thickness and reducing the weight reduce by so much. (N.H.)

Neutron depolarization effects in a high-Tc superconductor (abstract)

Science.gov (United States)

Nunes, A. C.; Pickart, S. J.; Crow, L.; Goyette, R.; McGuire, T. R.; Shinde, S.; Shaw, T. M.

1988-11-01

Using the polarized beam small-angle neutron scattering spectrometer at the Rhode Island Nuclear Science Center Reactor, we have observed significant depolarization of a neutron beam by passage through polycrystalline high-Tc superconductors, specifically 123 Y-Ba-Cu-O prepared and characterized at the IBM Watson Research Center. We believe that this technique will prove useful in studying aspects of these materials, such as the penetration depth of shielding currents, the presence and structure of trapped flux vortices, and grain size effects on the supercurrent distribution in polycrystalline samples. The two samples showed sharp transitions at 87 and 89 K, and have been studied at temperatures of 77 K; the second sample has also been studied at 4 K. The transition to the superconducting state was monitored by the shift in resonant frequency of a coil surrounding the sample. No measurable depolarization was observed in either sample at 77 K in both the field-cooled and zero-field-cooled states, using applied fields of 0 (nominal), 54, and 1400 Oe. This negative result may be connected with the fact that the material is still in the reversible region as indicated by susceptibility measurements, but it allows an estimate of the upper bound of possible inhomogeneous internal fields, assuming a distance scale for the superconducting regions. For the 10-μm grain size suggested by photomicrographs, this upper bound for the field turns out to be 1.2 kOe, which seems reasonable. At 4 K a significant depolarization was observed when the sample was cooled in low fields and a field of 1400 Oe was subsequently applied. This result suggests that flux lines are penetrating the sample. Further investigations are being carried out to determine the field and temperature dependence of the depolarization, and attempts will be made to model it quantitatively in terms of possible internal field distributions. We are also searching for possible diffraction effects from ordered vortex

Investigation of water content in primary upper shield of high temperature engineering test reactor (HTTR)

International Nuclear Information System (INIS)

Sumita, Junya; Sawa, Kazuhiro; Mogi, Haruyoshi; Itahashi, Shuuji; Kitami, Toshiyuki; Akutu, Youichi; Fuchita, Yasuhiro; Kawaguchi, Toru; Moriya, Masahiro

1999-09-01

A primary upper shield of the High Temperature Engineering Test Reactor (HTTR) is composed of concrete (grout) which is packed into iron frames. The main function of the primary upper shield is to attenuate neutron and gamma ray from the core, that leads to satisfy dose equivalent rate limit of operating floor and stand-pipe room. Water content in the concrete is one of the most important things because it strongly affects neutron-shielding ability. Then, we carried out out-of-pile experiments to investigate relationship between temperature and water content in the concrete. Based on the experimental results, a hydrolysis-diffusion model was developed to investigate water release behavior from the concrete. The model showed that water content used for shielding design in the primary upper shield of the HTTR will be maintained if temperature during operating life is under 110degC. (author)

Shielding for high energy, high intensity electron accelerator installation

International Nuclear Information System (INIS)

Warawas, C.; Chongkum, S.

1997-03-01

The utilization of electron accelerators (eBA) is gradually increased in Thailand. For instance, a 30-40 MeV eBA are used for tumor and cancer therapy in the hospitals, and a high current eBA in for gemstone colonization. In the near future, an application of eBA in industries will be grown up in a few directions, e.g., flue gases treatment from the coal fire-power plants, plastic processing, rubber vulcanization and food preservation. It is the major roles of Office of Atomic Energy for Peace (OAEP) to promote the peaceful uses of nuclear energy and to regulate the public safety and protection of the environment. By taking into account of radiation safety aspect, high energy electrons are not only harmful to human bodies, but the radioactive nuclides can be occurred. This report presents a literature review by following the National Committee on Radiation Protection and Measurements (NCRP) report No.31. This reviews for parametric calculation and shielding design of the high energy (up to 100 MeV), high intensity electron accelerator installation

Physical properties of high-Tc superconducting oxides. Modification of tc using organic dopants. Final report. Proprietes physiques d'oxydes supraconducteurs a haute Tc. Modification de tc sous l'effet de dopants organiques

Energy Technology Data Exchange (ETDEWEB)

Brau, A

1993-01-01

An attempt was made to significantly modify the Tc transition temperature of certain copper-based superconducting oxides by introducing organic or mineral dopants, and to study the mobility of 300K-carriers in crystallized tallium-base superconducting oxides. Since the critical transition temperature of superconducting oxides is highly influenced by the density of the free carriers they contain, the authors tried making superconducting powders react with either an organic electron acceptor or a mineral compound. The goal was to increase the density of the holes by altering the copper's degree of oxidation. Their preparatory work showed a direct charge-transfer reaction between the electron-donor copper and the acceptor TCNQ and studied the degree to which the electron acceptor can alter the copper's oxidation. Initial results also showed that dopants can affect superconducting Tc and the course of R(T) curves.

Characteristics of YBa2Cu3O7 high-Tc superconductor with KCl

Science.gov (United States)

Yoon, Ki Hyun; Chang, Sung Sik

1990-03-01

The lattice parameters, microstructural change, transition temperature, and electrical properties of the YBa2-xKxCu3O7 high-Tc superconductor in the range from x=0 to x=0.25 have been investigated. The high-Tc orthorhombic phase increases with increasing KCl up to x=0.20, above which it decreases. The lattice parameters decrease with increasing KCl up to x=0.10, and then become nearly uniform. The grain size increases with increasing KCl up to x=0.20 due to its role as sintering agent. The specimens with x=0.2 have transition temperatures of 96 K and high magnetic susceptibility due to the contraction of lattice parameters a and b and the increase of orthorhombic distortion.

A Cryogenic Magnetostrictive Actuator Using a Persistent High Temperature Superconducting Magnet. Part 1; Concept and Design

Science.gov (United States)

Horner, Garnett; Bromberg, Leslie; Teter, J. P.

2000-01-01

Cryogenic magnetostrictive materials, such as rare earth zinc crystals, offer high strains and high forces with minimally applied magnetic fields, making the material ideally suited for deformable optics applications. For cryogenic temperature applications the use of superconducting magnets offer the possibility of a persistent mode of operation, i.e., the magnetostrictive material will maintain a strain field without power. High temperature superconductors (HTS) are attractive options if the temperature of operation is higher than 10 degrees Kelvin (K) and below 77 K. However, HTS wires have constraints that limit the minimum radius of winding, and even if good wires can be produced, the technology for joining superconducting wires does not exist. In this paper, the design and capabilities of a rare earth zinc magnetostrictive actuator using bulk HTS is described. Bulk superconductors can be fabricated in the sizes required with excellent superconducting properties. Equivalent permanent magnets, made with this inexpensive material, are persistent, do not require a persistent switch as in HTS wires, and can be made very small. These devices are charged using a technique which is similar to the one used for charging permanent magnets, e.g., by driving them into saturation. A small normal conducting coil can be used for charging or discharging. Because of the magnetic field capability of the superconductor material, a very small amount of superconducting magnet material is needed to actuate the rare earth zinc. In this paper, several designs of actuators using YBCO and BSCCO 2212 superconducting materials are presented. Designs that include magnetic shielding to prevent interaction between adjacent actuators will also be described. Preliminary experimental results and comparison with theory for BSCCO 2212 with a magnetostrictive element will be discussed.

Neutron shielding material

International Nuclear Information System (INIS)

Nodaka, M.; Iida, T.; Taniuchi, H.; Yosimura, K.; Nagahama, H.

1993-01-01

From among the neutron shielding materials of the 'kobesh' series developed by Kobe Steel, Ltd. for transport and storage packagings, silicon rubber base type material has been tested for several items with a view to practical application and official authorization, and in order to determine its adaptability to actual vessels. Silicon rubber base type 'kobesh SR-T01' is a material in which, from among the silicone rubber based neutron shielding materials, the hydrogen content is highest and the boron content is most optimized. Its neutron shielding capability has been already described in the previous report (Taniuchi, 1986). The following tests were carried out to determine suitability for practical application; 1) Long-term thermal stability test 2) Pouring test on an actual-scale model 3) Fire test The experimental results showed that the silicone rubber based neutron shielding material has good neutron shielding capability and high long-term fire resistance, and that it can be applied to the advanced transport packaging. (author)

sup(99m)Tc-2-mercaptopropionylglycine

International Nuclear Information System (INIS)

Saji, Hideo; Odori, Teruo; Morita, Rikushi; Yokoyama, Akira; Tanaka, Hisashi.

1979-01-01

Labeling of 2-mercaptopropionylglycine (2-MPG) with sup(99m)Tc, was studied and its chemical characteristics were examined. Further, biliary excretion behavior of this complex was comparatively estimated in mice, rats and rabbits. sup(99m)Tc-2-MPG was rapidly excreted in large quantities into the bile in mice and rats: within 1 hr after injection, 51% of the injected dose was recovered from the bile in rats. On the other hand, the ligand exchange reaction between this complex and penicillamine indicates that a low hydrolyzed sup(99m)Tc species is coordinated with 2-MPG. These results suggest that a low hydrolyzed sup(99m)Tc state is an effective feature in biliary excretion behavior of sup(99m)Tc compounds. Another interesting in vivo behavior of sup(99m)Tc-2-MPG is the difference observed in mice and rabbits: in mice, very high sup(99m)Tc activity is concentrated in the gallbladder and the clearance from tissues other than the gallbladder is rapid, whereas in rabbits, although a rapid and high excretion into the gallbladder is observed, a considerable high sup(99m)Tc activity is retained in the liver and the kidney. One reason for this different in vivo behavior is the low stability of this complex at high dilution: a big animal has the large dilution volume which lead to higher decomposition estimated by the higher liver and kidney retention or the lower bile excretion. In conclusion, studies carried on sup(99m)Tc-2-MPG showed a good biliary excretion behavior but an in vivo unstableness in big animals. (author)

Evaluation of Neutron shielding efficiency of Metal hydrides

Energy Technology Data Exchange (ETDEWEB)

Jeon, Sang Hwan; Chae, San; Kim, Yong Soo [Hanyang University, Seoul (Korea, Republic of)

2012-05-15

Neutron shielding is achieved of interaction with material by moderation and absorption. Material that contains large amounts hydrogen atoms which are almost same neutron atomic weight is suited for fast neutron shielding material. Therefore, polymers containing high density hydrogen atom are being used for fast neutron shielding. On the other hand, composite materials containing high thermal neutron absorption cross section atom (Li, B, etc) are being used for thermal neutron shielding. However, these materials have low fast neutron absorption cross section. Therefore, these materials are not suited for fast neutron shielding. Hydrogen which has outstanding neutron energy reduction ability has very low thermal neutron absorption cross section, almost cannot be used for thermal neutron shielding. In this case, a large atomic number material (Pb, U, etc.) has been used. Thus, metal hydrides are considered as complement to concrete shielding material. Because metal hydrides contain high hydrogen density and elements with high atomic number. In this research neutron shielding performance and characteristic of nuclear about metal hydrides ((TiH{sub 2}, ZrH{sub 2}, HfH{sub 2}) is evaluated by experiment and MCNPX using {sup 252}Cf neutron source as purpose development shielding material to developed shielding material

Comparison of sup(99m)Tc-MDP to sup(99m)Tc-pertechnetate by computerized quantitative joint scintigraphy

International Nuclear Information System (INIS)

Rekonen, A.; Moettoenen, T.; Oka, M.

1982-01-01

99mTc-pertechnetate was compared to 99mTc-MDP in joint pairs with asymmetric arthritis. Markedly elevated joint activity ratios (inflamed/uninflamed joint) were measured in all the joint pairs studied. In the joints affected by reactive arthritis and without roentgenologic changes the mean joint activity was the same with both tracers. A very high activity ratio with 99mTc-MDP was found in septic arthritis. In rheumatoid arthritis the sensitivity of 99mTc-MDP as an indicator of active arthritis seemed to be better than that of 99mTc-pertechnetate. Even in joints without erosions in roentgenograms the joint activity ratios were markedly elevated with 99mTc-MDP. This suggests, that high activity in 99mTc-MDP scanning might be prognostic of erosive joint changes. In this work a profile curve was used for quantitation differences between joints

High Tc screen-printed YBa2Cu3O(7-x) films - Effect of the substrate material

Science.gov (United States)

Bansal, Narottam P.; Simons, Rainee N.; Farrell, D. E.

1988-08-01

Thick films of YBa2Cu3O(7-x) have been deposited on highly polished alumina, magnesia spinel, nickel aluminum titanate (Ni-Al-Ti), and barium tetratitanate (Ba-Ti) substrates by the screen printing technique. Properties of the films were found to be highly sensitive to the choice of the substrate material. The film on Ba-Ti turned green after firing, due to a reaction with the substrate and were insulating. A film on Ni-Al-Ti had a Tc (onset) of about 95 K and lost 90 percent of its resistance by about 75 K. However, even at 4 K it was not fully superconducting, possibly due to a reaction between the film and the substrate and interdiffusion of the reaction products. The film on alumina had Tc (onset) of about 96 K, Tc (zero) of about 66 K, and Delta Tc of about 10 K. The best film was obtained on spinel and had Tc (onset) of about 94 K, zero resistance at 81 K, and a transition width of about 7 K.

Shielding calculation for treatment rooms of high energy linear accelerator

International Nuclear Information System (INIS)

Elleithy, M.A.

2006-01-01

A review of German Institute of Standardization (DIN) scheme of the shielding calculation and the essential data required has been done for X-rays and electron beam in the energy range from 1 MeV to 50 MeV. Shielding calculation was done for primary and secondary radiations generated during X-ray operation of Linac. In addition, shielding was done against X-rays generated (Bremsstrahlung) by useful electron beams. The calculations also covered the neutrons generated from the interactions of useful X-rays (at energies above 8 MeV) with the surrounding. The present application involved the computation of shielding against the double scattered components of X-rays and neutrons in the maze area and the thickness of the paraffin wax of the room door. A new developed computer program was designed to assist shielding thickness calculations for a new Linac installation or in replacing an existing machine. The program used a combination of published tables and figures in computing the shielding thickness at different locations for all possible radiation situations. The DIN published data of 40 MeV accelerator room was compared with the program calculations. It was found that there is good agreement between both calculations. The developed program improved the accuracy and speed of calculation

99mTc-MIBI, 99mTc-tetrofosmin and 99mTc-Q12 in vitro and in vivo

International Nuclear Information System (INIS)

Bernard, Bert F.; Krenning, Eric P.; Breeman, Wout A. P.; Ensing, Geert; Benjamins, Harry; Bakker, Willem H.; Visser, Theo J.; Jong, Marion de

1998-01-01

The aim of this study was to compare uptake of 99m Tc-MIBI, 99m Tc-tetrofosmin and 99m Tc-Q12 in vitro and biodistribution in vivo in rats. In vitro, uptake decreased in the order MIBI→tetrofosmin→Q12. Uptake of MIBI and tetrofosmin, but not of Q12, in cultured tumor cells was dependent on the plasma membrane and mitochondrial potential. In vivo, heart uptake of all three compounds was high and stable. Tumor uptake decreased in the order MIBI→Q12→tetrofosmin and the tumor/blood ratio in the order MIBI→tetrofosmin→Q12

Solubility of Tc(IV) oxides

International Nuclear Information System (INIS)

Liu, D.J.; Fan, X.H.

2005-01-01

Full text of publication follows: The deep geological disposal of the high level radioactive wastes is expected to be a safer disposal method in most countries. The long-lived fission product 99 Tc is present in large quantities in nuclear wastes and its chemical behavior in aqueous solution is of considerable interest. Under the reducing conditions, expected to exist in a deep geological repository, it is generally predicted that technetium will be present as TcO 2 .nH 2 O. The solubility of Tc(IV) is used as a source term in performance assessment of radioactive waste repository. Technetium oxide was prepared by reduction of a technetate solution with Sn 2+ . The solubility of Tc(IV) oxide has been determined in simulated groundwater and re-distilled water under aerobic and anaerobic conditions. The effects of pH and CO 3 2- concentration of solution on solubility of Tc(IV) oxide were studied. The concentration of total technetium and Tc(IV) species in the solutions were periodically determined by separating the oxidized and reduced technetium species using a solvent extraction procedure and counting the beta activity of the 99 Tc with a liquid scintillation counter. The experimental results show that the rate of oxidation of Tc(IV) in simulated groundwater and re-distilled water is about (1.49∼1.86) x 10 -9 mol/(L.d) under aerobic conditions, but Tc(IV) in simulated groundwater and re-distilled water is not oxidized under anaerobic conditions. Under aerobic or anaerobic conditions the solubility of Tc(IV) oxide in simulated groundwater and re-distilled water is equal on the whole after centrifugation or ultrafiltration. The solubility of Tc(IV) oxide decreases with the increase of pH at pH 10 and is pH independent in the range 2 -8 to 10 -9 mol/L at 2 3 2- concentration. These data could be used to estimate the Tc(IV) solubility for cases where solubility limits transport of technetium in reducing environments of high-level waste repositories. (authors)

The NMR probe of high-Tc materials and correlated electron systems

CERN Document Server

Walstedt, Russell E

2018-01-01

This new edition updates readers in three areas of NMR studies, namely, recent developments in high-Tc materials, heavy fermion systems and actinide oxides are presented.  The NMR probe has yielded a vast array of data for solid state materials, corresponding to different compounds, ionic sites, and nuclear species, as well as to a wide variety of experimental conditions. The last two parts of the book are completely new in this edition, while the first part has seen major updates. This edition features the latest developments for high-Tc materials, especially the advances in the area of pseudogap studies are reviewed.  An in depth overview of heavy fermion systems is presented in the second part,  notably Kondo lattices, quantum critical points and unconventional superconductivity are areas of intense research recently and are covered extensively. Finally, valuable information from NMR studies with actinide oxides will be provided. Ongoing analysis and discussion of NMR data have resulted in a wealth o...

Phenomenological Theory for Pseudogap States in High Tc Cuprate

Directory of Open Access Journals (Sweden)

Zhang Fuchun

2012-03-01

Full Text Available Pseudogap phase in the underdoped region of high-Tc cuprate is one of the challenging issues in condensed matter physics. In this talk, I will describe a phenomenological theory for this phase, based on analogies to the approach to Mott localization at weak coupling in lower dimensional systems. I will make comparisons of the theory to a series of the experiments, including angle resolved photoemission spectroscope, scanning tunneling microscope.

The exponential critical state of high-Tc ceramics

International Nuclear Information System (INIS)

Castro, H.; Rinderer, L.

1994-01-01

The critical current in high-Tc materials is strongly reduced by a magnetic field. We studied this dependency for tubular YBCO samples. We find an exponential drop as the field is increased from zero up to some tens of oersted. This behavior was already observed by others, however little work has been done in this direction. We define what we call the ''exponential critical state'' of HTSC and compare the prediction for the magnetization with experimental data. Furthermore, the ''Kim critical state'' is obtained as the small field limit. (orig.)

Evaluation of some resonance self-shielding procedures employed in high conversion light water reactor design

International Nuclear Information System (INIS)

Patino, N.E.; Abbate, M.J.; Sbaffoni, M.M.

1990-01-01

The procedures employed in the treatment of the resonance shielding effect have been identified as one of the causes of the large discrepancies found in the neutronic calculation of high conversion light water reactors (HCLWRs), indicating the need for a revision of the self-shielding procedures employed. In this work some well known techniques applied in HCLWR self-shielding calculations are evaluated; the study involves the comparison of methods for the generation of group constants, the analysis of the impact of considering some isotopes as infinitely diluted and the evaluation of the usual approximations utilized for the treatment of heterogeneities

Shielding ability of lead loaded radiation resistant gloves

International Nuclear Information System (INIS)

Kawano, Takao; Ebihara, Hiroshi

1990-01-01

The shielding ability of radiation resistant gloves were examined. The gloves are made of lead loaded (as PbO 2 ) polyvinyl chloride resin and are about 0.4 mm of thickness (70 mg/cm 2 ). Eleven test pieces were sampled from each of three gloves (total were thirty three) and the transmission rates for radiations (X-ray or γ-ray) through the test pieces were measured with radiation sources, 99m Tc, 57 Co, 133 Ba, 133 Xe and 241 Am. The differences of the transmission rate for radiations by the positions of the gloves were smaller than 15%, and the differences by three gloves were smaller than 5% in the case of 60 keV and 141 keV radiations. The average transmission rates for radiations in thirty three test pieces were about 40% for 30 keV radiation, about 90% for 80 keV and 140 keV radiations. The shielding characteristic of the gloves could be equivalent to about 0.026 mm thick lead plate. (author)

Magnetic shielding for superconducting RF cavities

Science.gov (United States)

Masuzawa, M.; Terashima, A.; Tsuchiya, K.; Ueki, R.

2017-03-01

Magnetic shielding is a key technology for superconducting radio frequency (RF) cavities. There are basically two approaches for shielding: (1) surround the cavity of interest with high permeability material and divert magnetic flux around it (passive shielding); and (2) create a magnetic field using coils that cancels the ambient magnetic field in the area of interest (active shielding). The choice of approach depends on the magnitude of the ambient magnetic field, residual magnetic field tolerance, shape of the magnetic shield, usage, cost, etc. However, passive shielding is more commonly used for superconducting RF cavities. The issue with passive shielding is that as the volume to be shielded increases, the size of the shielding material increases, thereby leading to cost increase. A recent trend is to place a magnetic shield in a cryogenic environment inside a cryostat, very close to the cavities, reducing the size and volume of the magnetic shield. In this case, the shielding effectiveness at cryogenic temperatures becomes important. We measured the permeabilities of various shielding materials at both room temperature and cryogenic temperature (4 K) and studied shielding degradation at that cryogenic temperature.

Shielding measurements and augmentation for high power operations of FBTR

International Nuclear Information System (INIS)

Jose, M.T.; Baskar, S.; Viswanathan, S.; Balasundar, S.; Subramanian, V.; Ravi, T.; Sundaram, V.M.; Raghunath, V.M.; Varadarajan, S.; Jena, A.K.

1996-01-01

Fast breeder test reactor (FBTR) at Kalpakkam is a 40 MWt loop type fast reactor with sodium coolant. Since criticality in 1985, radiation surveys were carried out at all accessible locations at different power levels to find out the hot spots and evaluate the shielding adequacy. This paper gives the details of findings of these measurements, consequent changes in shielding, and the present status of dose profile after the augmentation of shielding. (author). 1 ref., 1 fig., 1 tab

Analysis of eddy current loss in high-Tc superconducting power cables with respect to various structure of stabilizer

International Nuclear Information System (INIS)

Choi, S. J.; Song, M. K.; Lee, S. J.; Cho, J. W.; Sim, K. D.

2005-01-01

The High-Tc superconducting power cable consists of a multi-layer high-Tc superconducting cable core and a stabilizer which is used to bypass the current at fault time. Eddy current loss is generated in the stabilizer in normal operating condition and affects the whole system. In this paper, the eddy current losses are analyzed with respect to various structure of stabilizer by using opera-3d. Moreover, optimal conditions of the stabilizer are derived to minimize the eddy current losses from the analyzed results. The obtained results could be applied to the design and manufacture of the high-Tc superconducting power cable system.

Orbitals, correlation, valencies in high-Tc superconductors

International Nuclear Information System (INIS)

Khomskii, D.I.

1990-09-01

The survey is given of certain properties of high-Tc superconductors connected with the details of their electronic structure such as the kind of orbitals involved and the degree of correlation. Special attention is paid to the properties of cuprates at high doping level. The problem whether there exists a ''Mott transition'' at high electron or a hole concentration is discussed. We also discuss physical factors (d-p Coulomb interaction, orbital mixing) leading to the partial occupation of copper d x 2 -orbital. In particular we show that in localized picture (x 2 -y 2 ) and z 2 -levels in La 2-x Sr x CuO 4 may cross at x approx. 0.4 which may be responsible for a marked change of many properties at this doping. The possible role of x 2 -electrons in pairing is discussed in connection with some recent experiments. (author). 28 refs, 6 figs, 1 tab

Preparation of 99mTc-thiourea complex as a precursor for Tc(III) labeled compounds

International Nuclear Information System (INIS)

Rey, A.; Teran, M.; Molina, S.; Leon, A.; Kremer, C.; Gambino, D.; Kremer, E.

1996-01-01

Ligand exchange is one of the possible synthetic routes to obtain 99m Tc coordination compounds. However, the success of this route depends on the availability of good precursors. The objective of this work is the preparation of the complex [ 99m Tc (tu) 6 ] 3+ (tu = thiourea), as a potential precursor for 99m Tc(III) coordination compounds. The preparation was successfully performed in acidic conditions, the excess of tu serving as reducing agent. At pH values higher than 3, the compound becomes unstable and on addition of polydentate ligands new Tc(III) complexes are formed. With edta, the complex 99m Tc(III)-edta was obtained in high yield. (author). 13 refs., 3 tabs

Nuclear data for radiation shielding

International Nuclear Information System (INIS)

Miyasaka, Shunichi; Takahashi, Hiroshi.

1976-01-01

The third shielding expert conference was convened in Paris in Oct. 1975 for exchanging informations about the sensitivity evaluation of nuclear data in shielding calculation and integral bench mark experiment. The requirements about nuclear data presented at present from the field of nuclear design do not reflect sufficiently the requirements of shielding design, therefore it was the object to gather the requirements about nuclear data from the field of shielding. The nuclides used for shielding are numerous, and the nuclear data on these isotopes are required. Some of them cannot be ignored as the source of secondary γ-ray or in view of the radioactivation of materials. The requirements for the nuclear data of neutrons in the field of shielding are those concerning the reaction cross sections producing secondary γ-ray, the reaction cross sections including the production of secondary neutrons, elastic scattering cross sections, and total cross sections. The topics in the Paris conference about neutron shielding data are described, such as the methodology of sensitivity evaluation, the standardization of group constant libraries, the bench mark experiment on iron and sodium, and the cross section of γ-ray production. In the shielding of nuclear fission reactors, the γ-ray production owing to nuclear fission reaction is also important. In (d, t) fusion reactors, high energy neutrons are generated, and high energy γ-ray is emitted through giant E1 resonance. (Kako, I.)

Passive magnetic shielding in MRI-Linac systems

Science.gov (United States)

Whelan, Brendan; Kolling, Stefan; Oborn, Brad M.; Keall, Paul

2018-04-01

Passive magnetic shielding refers to the use of ferromagnetic materials to redirect magnetic field lines away from vulnerable regions. An application of particular interest to the medical physics community is shielding in MRI systems, especially integrated MRI-linear accelerator (MRI-Linac) systems. In these systems, the goal is not only to minimize the magnetic field in some volume, but also to minimize the impact of the shield on the magnetic fields within the imaging volume of the MRI scanner. In this work, finite element modelling was used to assess the shielding of a side coupled 6 MV linac and resultant heterogeneity induced within the 30 cm diameter of spherical volume (DSV) of a novel 1 Tesla split bore MRI magnet. A number of different shield parameters were investigated; distance between shield and magnet, shield shape, shield thickness, shield length, openings in the shield, number of concentric layers, spacing between each layer, and shield material. Both the in-line and perpendicular MRI-Linac configurations were studied. By modifying the shield shape around the linac from the starting design of an open ended cylinder, the shielding effect was boosted by approximately 70% whilst the impact on the magnet was simultaneously reduced by approximately 10%. Openings in the shield for the RF port and beam exit were substantial sources of field leakage; however it was demonstrated that shielding could be added around these openings to compensate for this leakage. Layering multiple concentric shield shells was highly effective in the perpendicular configuration, but less so for the in-line configuration. Cautious use of high permeability materials such as Mu-metal can greatly increase the shielding performance in some scenarios. In the perpendicular configuration, magnetic shielding was more effective and the impact on the magnet lower compared with the in-line configuration.

A detector for use in high energy bremsstrahlung shielding studies

International Nuclear Information System (INIS)

Wilson, O.J.; Thomson, J.E.M.

1983-01-01

The design, development and calibration of a detector based on the principle of the Moxon-Rae detector is discussed. It is ideally suited to the measurement of the energy fluence of photons transmitted through a thick shield which has been irradiated with high energy bremsstrahlung. The detection sensitivity is 10 4 to 10 5 times that of the P2 ion chamber

Using depleted uranium to shield vitrified high-level waste packages

International Nuclear Information System (INIS)

Yoshimura, H.R.; Gildea, P.D.; Bernard, E.A.

1995-01-01

The underlying report for this paper evaluates options for using depleted uranium as shielding materials for transport systems for disposal of vitrified high-level waste (VHLW). In addition, economic analyses are presented to compare costs associated with these options to costs, associated with existing and proposed storage, transport, and diposal capabilities. A more detailed evaluation is provided elsewhere. (Yoshimura et al. 1995.)

Improvement of critical currents in Bi-2223 bulk superconductors

International Nuclear Information System (INIS)

Eujen, R.; Brauer, D.J.; Huedepohl, J.

1991-01-01

Potential applications of the high-Tc superconductors for energy transport or high-field magnets require high critical current densities. A limiting factor in polycrystalline oxidic materials is the quality of the grain boundaries. Weak links have been made responsible for the steep decrease in the critical current density j c upon application of even weak magnetic fields of YBa CuO whereas flux creep seems to dominate the obtainable j c values for the Bi-Sr-Ca-Cu-O system (BSCCO) at 77 K. In the lead containing material (BPSCCO) the formation of a porous microstructure is enhanced by the platelike shape of the crystals. Special techniques such as powder-in-tube, hot isostatic pressing, zone melting or application of fluxes have been used in order to improve the grain contacts. A positive influence of fluxes on j c , e.g. by addition of Ca 2 CuO 3 or Ag 2 O, has been reported. In this study we have investigated the influence of various compositions and conditions on the formation of the BSCCO-2223 phase (T c ca. 107 K), the critical current density j c , and the magnet field dependence of the a.c. susceptibility. (orig.)

Positron annihilation study of the high-Tc (Bi, Pb)2Sr2Ca2Cu3Ox superconductor

International Nuclear Information System (INIS)

Lim, H.J.; Byrne, J.G.

1997-01-01

Positron lifetime spectroscopy (PLS) and positron Doppler-broadening spectroscopy (PDBS) were applied to the high-T c lead-doped Bi 2 Sr 2 Ca 2 Cu 3 O x (BPSCCO 2223) superconductor as a function of temperature. Neither positron lifetimes nor Doppler parameters (S, W, and S/W) showed significant change through T c . This may result from having the highest positron density in the open BiO 2 double layers and no significant positron density in the superconducting CuO 2 layers where positrons, if mainly present, are known to be sensitive to the transition in other high-T c superconductors. Doppler parameters showed that the probability of positron annihilations with core electrons in the lattice slightly increased and that the probability of positron annihilations with conduction electrons slightly decreased as temperature decreased from ambient temperature to 20 K. The lifetime associated with positron annihilations in the perfect lattice of the sample (τ 1 ) was 209 ps and, due to the annihilations at internal surfaces or voids in the sample (τ 2 ) was about 540 ps, independent of temperature. Finally, the mean lifetime for BSCCO 2223 was about 307 ps. (orig.)

Basic design of shield blocks for a spallation neutron source under the high-intensity proton accelerator project

Energy Technology Data Exchange (ETDEWEB)

Yoshida, Katsuhiko; Maekawa, Fujio; Takada, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2003-03-01

Under the JAERI-KEK High-Intensity Proton Accelerator Project (J-PARC), a spallation neutron source driven by a 3 GeV-1 MW proton beam is planed to be constructed as a main part of the Materials and Life Science Facility. Overall dimensions of a biological shield of the neutron source had been determined by evaluation of shielding performance by Monte Carlo calculations. This report describes results of design studies on an optimum dividing scheme in terms of cost and treatment and mechanical strength of shield blocks for the biological shield. As for mechanical strength, it was studied whether the shield blocks would be stable, fall down or move to a horizontal direction in case of an earthquake of seismic intensity of 5.5 (250 Gal) as an abnormal load. For ceiling shielding blocks being supported by both ends of the long blocks, maximum bending moment and an amount of maximum deflection of their center were evaluated. (author)

Basic design of shield blocks for a spallation neutron source under the high-intensity proton accelerator project

CERN Document Server

Yoshida, K; Takada, H

2003-01-01

Under the JAERI-KEK High-Intensity Proton Accelerator Project (J-PARC), a spallation neutron source driven by a 3 GeV-1 MW proton beam is planed to be constructed as a main part of the Materials and Life Science Facility. Overall dimensions of a biological shield of the neutron source had been determined by evaluation of shielding performance by Monte Carlo calculations. This report describes results of design studies on an optimum dividing scheme in terms of cost and treatment and mechanical strength of shield blocks for the biological shield. As for mechanical strength, it was studied whether the shield blocks would be stable, fall down or move to a horizontal direction in case of an earthquake of seismic intensity of 5.5 (250 Gal) as an abnormal load. For ceiling shielding blocks being supported by both ends of the long blocks, maximum bending moment and an amount of maximum deflection of their center were evaluated.

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.

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

International Nuclear Information System (INIS)

Zorla, Eyüp; Ipbüker, Cagatay; Biland, Alex; Kiisk, Madis; Kovaljov, Sergei; Tkaczyk, Alan H.; Gulik, Volodymyr

2017-01-01

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.

Vertical distributions of (99)Tc and the (99)Tc/(137)Cs activity ratio in the coastal water off Aomori, Japan.

Science.gov (United States)

Nakanishi, Takahiro; Zheng, Jian; Aono, Tatsuo; Yamada, Masatoshi; Kusakabe, Masashi

2011-08-01

Using a sector-field ICP-MS the vertical distributions of the (99)Tc concentration and (99)Tc/(137)Cs activity ratio were measured in the coastal waters off Aomori Prefecture, Japan, where a spent-nuclear-fuel reprocessing plant has begun test operation. The (99)Tc concentrations in surface water ranged from 1.8 to 2.4 mBq/m(3), no greater than the estimated background level. Relatively high (99)Tc/(137)Cs activity ratios (10-12 × 10(-4)) would be caused by the inflow of the high-(99)Tc/(137)Cs water mass from the Japan Sea. There is no observable contamination from the reprocessing plant in the investigated area. The (99)Tc concentration and the (99)Tc/(137)Cs activity ratio in water column showed gradual decreases with depth. Our results implied that (99)Tc behaves in a more conservative manner than (137)Cs in marine environments. Copyright © 2011 Elsevier Ltd. All rights reserved.

Shielding practice

International Nuclear Information System (INIS)

Sauermann, P.F.

1985-08-01

The basis of shielding practice against external irradiation is shown in a simple way. For most sources of radiation (point sources) occurring in shielding practice, the basic data are given, mainly in the form of tables, which are required to solve the shielding problems. The application of these data is explained and discussed using practical examples. Thickness of shielding panes of glove boxes for α and β radiation; shielding of sealed γ-radiography sources; shielding of a Co-60 radiation source, and of the manipulator panels for hot cells; damping factors for γ radiation and neutrons; shielding of fast and thermal neutrons, and of bremsstrahlung (X-ray tubes, Kr-85 pressure gas cylinders, 42 MeV betatrons, 20 MeV linacs); two-fold shielding (lead glass windows for hot cells, 14 MeV neutron generators); shielding against scattered radiation. (orig./HP) [de

Electromagnetic wave absorption in high-Tc superconductors and its application

International Nuclear Information System (INIS)

Porjesz, T.; Khatiashvili, N.; Kovacs, Gy.; Leppavuori, S.; Uusimaki, A.; Kokkomaki, T.; Hagberg, J.

1995-08-01

The experimental study of the electromagnetic wave absorption of high-Tc superconductors subjected to small magnetic fields has been extended to a wide frequency range. The results obtained show an almost frequency independent behaviour in the 4 MHz - 20 GHz region. The measurement technique for the high frequency regime was developed in such a way that the sensitivity increased so much that the sample under investigation could be used as a very sensitive magnetic field detector, too. (author). 4 refs, 8 figs, 1 tab

Comparison of carrier-added [99mTc] EDTMP and carrier-free preparations of [99mTc] EDTMP and [99mTc] DPD

International Nuclear Information System (INIS)

Krcal, A.; Kletter, K.; Dudczak, R.; Pirich, C.; Mitterhauser, M.

2002-01-01

Full text: High uptake of bone-seeking radiopharmaceuticals in malignant bone lesions is a prerequisite for adequate bone scanning. Visual image analysis is impaired due to high soft-tissue activity with currently available [ 99m Tc]-EDTMP-kits. This study aimed to compare carrier-added [ 99m Tc]-EDTMP with carrier-free [ 99m Tc]-EDTMP and [ 99m Tc]-DPD preparations in clinical routine. 15 μg and 150 μg perrhenic acid respectively were added to [ 99m Tc]-pertechnetate (>6 GBq in 3 ml phys. saline). The solution was then transferred into a vial, containing 1 mg of EDTMP, 3.6 mg stannous(II)chloride and 10 mg ascorbic acid under inert conditions. Under vigorous stirring the reaction mixture was heated to 45 o C for 10 min. After cooling down to room temperature the labelling mixture was sterile filtrated (millipore 0.22 μm). Quality control was performed using radio-ITLC (Whatman SG; acetone or ethanol: R f perrhenate/pertechnetate 0.87, colloid/product 0.05; phys. saline: R f colloid 0.00, perrhenate/pertechnetate and product 0.9) allowing rapid and efficient assessment of the product. Carrier free [ 99m Tc]-EDTMP and [ 99m Tc]-DPD were prepared according to instructions of the manufacturer. Clinical studies were performed in 29 patients according to a routine bone scanning protocol by injecting 700-800 MBq of the respective tracer and whole body imaging 3 h thereafter. Radiochemical purity and radiochemical yield relied on various parameters such as concentration of carrier and reducing agent and reaction conditions (pH, reaction time, temperature). Means of the labelling yield were 22 % for the preparation using 150 μg of carrier (5 preparations), 80 % for the preparation using 15 μpg of carrier (10 preparations) and 91 % for the carrier free products (5 preparations). Radiochemical purity was >96 % in all experiments. Colloid was formed in very low amounts, and was completely removed by sterile filtration. In clinical studies quantitative analysis

99mTc(CO)3-DTMA bombesin conjugates having high affinity for the GRP receptor

International Nuclear Information System (INIS)

Lane, Stephanie R.; Veerendra, Bhadrasetty; Rold, Tammy L.; Sieckman, Gary L.; Hoffman, Timothy J.; Jurisson, Silvia S.; Smith, Charles J.

2008-01-01

Introduction: Targeted diagnosis of specific human cancer types continues to be of significant interest in nuclear medicine. 99m Tc is ideally suited as a diagnostic radiometal for in vivo tumor targeting due to its ideal physical characteristics and diverse labeling chemistries in numerous oxidation states. Methods: In this study, we report a synthetic approach toward design of a new tridentate amine ligand for the organometallic aqua-ion [ 99m Tc(H 2 O) 3 (CO) 3 ] + . The new chelating ligand framework, 2-(N,N'-Bis(tert-butoxycarbonyl)diethylenetriamine) acetic acid (DTMA), was synthesized from a diethylenetriamine precursor and fully characterized by mass spectrometry and nuclear magnetic resonance spectroscopy ( 1 H and 13 C). DTMA was conjugated to H 2 N-(X)-BBN(7-14)NH 2 , where X=an amino acid or aliphatic pharmacokinetic modifier and BBN=bombesin peptide, by means of solid phase peptide synthesis. DTMA-(X)-BBN(7-14)NH 2 conjugates were purified by reversed-phase high-performance chromatography and characterized by electrospray-ionization mass spectrometry. Results: The new conjugates were radiolabeled with [ 99m Tc(H 2 O) 3 (CO) 3 ] + produced via Isolink radiolabeling kits to produce [ 99m Tc(CO) 3 -DTMA-(X)-BBN(7-14)NH 2 ]. Radiolabeled conjugates were purified by reversed-phase high-performance chromatography. Effective receptor binding behavior was evaluated in vitro and in vivo. Conclusions: [ 99m Tc(CO) 3 -DTMA-(X)-BBN(7-14)NH 2 ] conjugates displayed very high affinity for the gastrin releasing peptide receptor in vitro and in vivo. Therefore, these conjugates hold some propensity to be investigated as molecular imaging agents that specifically target human cancers uniquely expressing the gastrin releasing peptide receptor subtypes

Measuring space radiation shielding effectiveness

OpenAIRE

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

2017-01-01

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 ...

Radiation shielding device

International Nuclear Information System (INIS)

Nakagawa, Takahiro; Yamagami, Makoto.

1996-01-01

A fixed shielding member made of a radiation shielding material is constituted in perpendicular to an opening formed on radiation shielding walls. The fixed shielding member has one side opened and has other side, the upper portion and the lower portion disposed in close contact with the radiation shielding walls. Movable shielding members made of a radiation shielding material are each disposed openably on both side of the fixed shielding member. The movable shielding member has a shaft as a fulcrum on one side thereof for connecting it to the radiation shielding walls. The other side has a handle attached for opening/closing the movable shielding member. Upon access of an operator, when each one of the movable shielding members is opened/closed on every time, leakage of linear or scattered radiation can be prevented. Even when both of the movable shielding members are opened simultaneously, the fixed shielding member and the movable shielding members form labyrinth to prevent leakage of linear radioactivity. (I.N.)

Models of high-Tc superconductivity and applications to electric generators and motors

DEFF Research Database (Denmark)

Sørensen, Mads Peter

We present the Ginzburg Landau model for mesoscopic high-Tc superconductors of complex geometry. It is shown that giant vortices can form at boundary defects. The relation between total magnetic flux penetration through the superconductor and the externally applied field is established. This is i...

Superconducting magnetic shields production. Realisation d'ecrans magnetiques supraconducteurs

Energy Technology Data Exchange (ETDEWEB)

Lainee, F; Kormann, R [Thomson-CSF, Domaine de Corbeville, 91 - Orsay (FR); Lainee, F [Ecole des Mines de Paris, 91 - Evry (FR)

1992-02-01

Low fields and low frequency shielding properties of YBCO magnetic shields are measured at 77 K. They compare favourably with shielding properties of mumetal shields. Therefore high-T{sub c} superconducting magnetic shields can already be used to shield small volumes. The case of magnetic shields for large volumes is also discussed. 3 refs; 6 figs; 4 tabs.

Internal friction of flux motion in Hg-system high-Tc superconductors

International Nuclear Information System (INIS)

Tian, W.; Zhu, J.S.; Shao, H.M.; Li, J.; Wang, Y.N.

1996-01-01

The internal friction(IF) and modulus as functions of temperature were measured for several Hg-system high-Tc superconductors(Hg1201, Hg1223, Hg1223 doped with Fe and Pb), under the applied magnetic field, with vibrating reed technique. An IF peak associated with flux motion can be found below Tc for all samples. The temperature of the IF peak increases with reducing vibrating amplitude. This amplitude dependence of IF indicates that the flux motion is characterized by nonlinear behavior. No apparent shift of IF peak position can be detected by varying the frequency in the range from 10 2 Hz to 10 3 Hz. Furthermore, the IF peak height satisfies a scaling law Q -1 ∝ω -n . This may be originated from phase transition of flux line lattice(FLL) rather than a thermally activated diffusion process. (orig.)

Angle-resolved photoelectron spectroscopy studies of the many-body effects in the electronic structure of high-Tc cuprates

International Nuclear Information System (INIS)

Inosov, Dmytro S.

2008-01-01

In the present work some steps are done towards understanding the anomalous effects observed in the single-particle excitation spectra of cuprates. First, the electronic properties of BSCCO are considered. The main result of this part of the work is a model of the Green's function that is later used for calculating the two-particle excitation spectrum. Then, the matrix element effects in the photoemission spectra of cuprates are discussed. After a general introduction to the problem, the thesis focuses on the recently discovered anomalous behavior of the ARPES spectra that partially originates from the momentum-dependent photoemission matrix element. The momentum- and excitation energy dependence of the anomalous high-energy dispersion, termed ''waterfalls'', is covered in full detail. Understanding the role of the matrix element effects in this phenomenon proves crucial, as they obstruct the view of the underlying excitation spectrum that is of indisputable interest. For the optimally doped bilayer Bi-based cuprate, the renormalized two-particle correlation function in the superconducting state is calculated from ARPES data within an itinerant model based on the random phase approximation (RPA). (orig.)

Isomeric and high-spin states of 94Tc and the search for yrast isomers near Napprox.50

International Nuclear Information System (INIS)

Lee, I.Y.; Johnson, N.R.; McGowan, F.K.; Young, G.R.; Guidry, M.W.; Yates, S.W.

1981-01-01

A search for isomers in the Napprox.50 region has produced no evidence of high-spin yrast isomerism. A new 4.5-ns low-multiplicity isomer has been identified and assigned to 94 Tc, while the yrast sequence of 94 Tc has been established to more than 5 MeV in excitation energy

International Discussion Meeting on High-Tc Superconductors

CERN Document Server

1988-01-01

In the past two years conferences on superconductivity have been characterized by the attendance of hundreds of scientists. Consequently, the organizers were forced to schedule numerous parallel sessions and poster presentations with an almost unsurveyable amount of information. It was, therefore, felt that a more informal get-together, providing ample time for a thourough discussion of some topics of current interest in high-temperature superconductivity, was timely and benefitial for leading scientists as well as for newcomers in the field. The present volume contains the majority of papers presented at the International Discussion Meeting on High-Tc Superconductors held at the Mauterndorf Castle in the Austrian Alps from February 7 to 11, 1988. Each subject was introduced in review form by a few invited speakers and then discussed together with the contributed poster presentations. These discussion sessions chaired by selected scientists turned out to be the highlights of the meeting, not only because all ...

Josephson junction between two high Tc superconductors with arbitrary transparency of interface

Directory of Open Access Journals (Sweden)

GhR Rashedi

2010-03-01

Full Text Available In this paper, a dc Josephson junction between two singlet superconductors (d-wave and s-wave with arbitrary reflection coefficient has been investigated theoretically. For the case of high Tc superconductors, the c-axes are parallel to an interface with finite transparency and their ab-planes have a mis-orientation. The physics of potential barrier will be demonstrated by a transparency coefficient via which the tunneling will occur. We have solved the nonlocal Eilenberger equations and obtained the corresponding and suitable Green functions analytically. Then, using the obtained Green functions, the current-phase diagrams have been calculated. The effect of the potential barrier and mis-orientation on the currents is studied analytically and numerically. It is observed that, the current phase relations are totally different from the case of ideal transparent Josephson junctions between d-wave superconductors and two s-wave superconductors. This apparatus can be used to demonstrate d-wave order parameter in high Tc superconductors.

Present Status and Future Prospects in Bulk Processing of HIGH-Tc Superconductors

Science.gov (United States)

Jin, S.; Chu, C. W.

The following sections are included: * INTRODUCTION * HIGH SUPERCONDUCTING TRANSITION TEMPERATURE * HIGH CRITICAL CURRENT DENSITY * Grain Boundary Weak Links * Nature of Weak Links * Possible Processing Approaches for Weak Link Problem * Processing Techniques for Texture Formation * Flux Creep in HTSC * Desirable Pinning Defects * Processing for Flux Pinning Enhancement * PROSPECTS FOR BULK APPLICATIONS * Magnetic Field Gener * Energy Storage * Magnetic Shielding * Other Applications * CONCLUDING REMARKS * ACKNOWLEDGMENT * REFERENCES

Non-equilibrium spectroscopy of high-Tc superconductors

International Nuclear Information System (INIS)

Krasnov, V M

2009-01-01

In superconductors, recombination of two non-equilibrium quasiparticles into a Cooper pair results in emission of excitation that mediates superconductivity. This is the basis of the proposed new type of 'non-equilibrium' spectroscopy of high T c superconductors, which may open a possibility for direct and unambiguous determination of the coupling mechanism of high T c superconductivity. In case of low T c superconductors, the feasibility of such the non-equilibrium spectroscopy was demonstrated in classical phonon generation-detection experiments almost four decades ago. Recently it was demonstrated that a similar technique can be used for high T c superconductors, using natural intrinsic Josephson junctions both for injection of non-equilibrium quasiparticles and for detection of the non-equilibrium radiation. Here I analyze theoretically non-equilibrium phenomena in intrinsic Josephson junctions. It is shown that extreme non-equilibrium state can be achieved at bias equal to integer number of the gap voltage, which can lead to laser-like emission from the stack. I argue that identification of the boson type, constituting this non-equilibrium radiation would unambiguously reveal the coupling mechanism of high Tc superconductors.

Concrete shielding for nuclear ship 'Mutsu'

International Nuclear Information System (INIS)

Nagase, Tetsuo; Nakajima, Tadao; Okumura, Tadahiko; Saito, Tetsuo

1983-01-01

The nuclear ship ''Mutsu'' was constructed in 1970 as the fourth in the world. On September 1, 1974, during the power raising test in the Pacific Ocean, radiation leak was detected. As the result of investigation, it was found that the cause was the fast neutrons streaming through the gap between the reactor pressure vessel and the primary shield. In order to repair the shielding facility, the Japan Nuclear Ship Research Development Agency carried out research and development and shielding design. It was decided to adopt serpentine concrete for the primary shield, which is the excellent moderator of fast neutrons even at high temperature, and heavy concrete for the secondary shield, which is effective for shielding both gamma ray and neutron beam. The repair of shielding was carried out in the Sasebo Shipyard, and completed in August, 1982. The outline of the repair work is reported. The weight increase was about 300 t. The conditions of the shielding design, the method of shielding analysis, the performance required for the shielding concrete, the preliminary experiment on heavy concrete and the construction works of serpentine concrete and heavy concrete are described. (Kako, I.)

Solubility study of Tc(IV) oxides

International Nuclear Information System (INIS)

Liu, D.J.; Fan, X.H.

2005-01-01

The deep geological disposal of the high level radioactive wastes is expected to be a safer disposal method in most countries. The long-lived fission product 99 Tc is present in large quantities in nuclear wastes and its chemical behavior in aqueous solution is of considerable interest. Under oxidizing conditions technetium exists as the anionic species TcO 4 - whereas under the reducing conditions, expected to exist in a deep geological repository, it is generally predicted that technetium will be present as TcO 2 ·nH 2 O. Hence, the mobility of Tc(IV) in reducing groundwater may be limited by the solubility of TcO 2 ·nH 2 O under these conditions. Due to this fact it is important to investigate the solubility of TcO 2 ·nH 2 O. The solubility determines the release of radionuclides from waste form and is used as a source term in radionuclide migration analysis in performance assessment of radioactive waste repository. Technetium oxide was prepared by reduction of a technetate solution with Sn 2 + . The solubility of Tc(IV) oxide has been determined in simulated groundwater and redistilled water under aerobic and anaerobic conditions. The effects of pH and CO 3 2- concentration of solution on solubility of Tc(IV) oxide were studied. The concentration of total technetium and Tc(IV) species in the solutions were periodically determined by separating the oxidized and reduced technetium species using a solvent extraction procedure and counting the beta activity of the 99 Tc with a liquid scintillation counter. The experimental results show that the rate of oxidation of Tc(IV) in simulated groundwater and redistilled water is about (1.49-1.86) x 10 -9 mol/(L·d) under aerobic conditions, but Tc(IV) in simulated groundwater and redistilled water is not oxidized under anaerobic conditions. Under aerobic or anaerobic conditions the solubility of Tc(IV) oxide in simulated groundwater and redistilled water is equal on the whole after centrifugation or ultrafiltration. The

Shielding plugs

International Nuclear Information System (INIS)

Makishima, Kenji.

1986-01-01

Purpose: In shielding plugs of an LMFBR type reactor, to restrain natural convection of heat in an annular space between a thermal shield layer and a shield shell, to prevent the lowering of heat-insulation performance, and to alleviate a thermal stress in a reactor container and the shield shell. Constitution: A ring-like leaf spring split in the direction of height is disposed in an annular space between a thermal shield layer and a shield shell. In consequence, the space is partitioned in the direction of height and, therefore, if axial temperature conditions and space width are the same and the space is low, the natural convection is hard to occur. Thus the rise of upper surface temperature of the shielding plugs can prevent the lowering of the heat insulation performance which will result in the increment of shielding plug cooling capacity, thereby improving reliability. In the meantime, since there is mounted an earthquake-resisting support, the thermal shield layer will move for a slight gap in case of an earthquake, being supported by the earthquake-resisting support, and the movement of the thermal shield layer is restricted, thereby maintaining integrity without increasing the stroke of the ring-like spring. (Kawakami, Y.)

93Tc and sup(93m)Tc gamma spectra

International Nuclear Information System (INIS)

Podkopaev, Yu.N.; Zarubin, P.P.; Kobelev, V.F.; Padalko, V.Yu.; Khrisanfov, Yu.V.

1977-01-01

The sup(93,93m)Tc decay was studied. The spectra of γ-rays accompanying the decay of this nuclide were studied. 93 Tc and sup(93m)Tc were obtained in the (dn)-reaction on 92 Mo. To ensure a more reliable identification of γ-rays, the isotopic composition of the targets, the bombardment time, the energy of the bombarding deuterons (5-12 MeV) and the spectrum processing program were varied. The energies and relative intensities of the γ-rays of the 93 Tc and sup(93m)Tc decay are listed in tables together with data of other investigatxons. The results obtained largely confirm the known data. Four new transitions were added in the sup(93m)Tc spectrum namely 1046.8, 2011.8, 2182.0, and 2861.5 keV. The 2739.0 keV transition was eliminated from the 93 Tc spectrum. The appropriate changes and additions were made in the 93 Tc decay scheme, and three new levels were introduced: 2479.0, 2821.7, and 3025.8 keV. The values of log ft of some levels of 93 Tc were estimated

Development of high-performance shielding material by heat curing method

Energy Technology Data Exchange (ETDEWEB)

Miura, Toshimasa; Hirao, Yoshihiro; Hayashi, Takayuki; Okuno, Koichi; Sato, Osamu [National Maritime Research Institute, Ibaraki (Japan)

2002-07-01

A high-performance shielding material is developed by a heat curing method. It is mainly made of a thermosetting resin, lead powder, and a boron compound. To make the resin, a single functional monomer stearyl methacrylate (SMA) is used. To get good dispersion of lead and the boron compound in the resin, the viscosity of the SMA is increased by adding a small amount of a peroxide into the liquid monomer and heating up to the temperature of 100 .deg. C. Next, a peroxide, lead powder, a boron compound, a three functional monomer, and a curing accelerator are mixed into the viscous SMA. The mixture is cured in an atmosphere of nitrogen after removing bubbles using a vacuum pump. Measured properties of the cured material are as follows. The curing rate of SMA is 97 %. The density is kept 2.35 g/cm{sub 3} in the range from room temperature to 150 .deg. C. The weight-change measured by a thermogravimetry is 0.16 % in the range from room temperature to 200 .deg. C. Details of fragments in the gas released from the material is analyzed by a gas chromatography and a mass spectrometry. The hydrogen content of the material is 6.04x10 {sub 22} /cm{sub 3} . The shielding effect is calculated for a fission source by an Sn code ANISN. The shielding effect of the curing material is excellent. For example, concrete shield of a certain thickness can be replaced by the material having a thickness less than a half of concrete. Several samples of the material are irradiated at an irradiation equipment of the research reactor JRR-4 installed at Japan Atomic Energy Research Institute. At the 14{sub th} day after irradiating with the thermal neutron fluence of 6.6x10{sub 15} /cm{sub 2} , the radioactivity is less than one tenth of 75 Bq/g above which materials are regulated as the radioactive substance in Japan.

Shielding structure analysis for LSDS facility

Energy Technology Data Exchange (ETDEWEB)

Choi, Hong Yeop; Kim, Jeong Dong; Lee, Yong Deok; Kim, Ho Dong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

The nuclear material (Pyro, Spent nuclear fuel) itself and the target material to generate neutrons is the LSDS system for isotopic fissile assay release of high intensity neutron and gamma rays. This research was performed to shield from various strong radiation. A shielding evaluation was carried out with a facilities model of LSDS system. The MCNPX 2.5 code was used and a shielding evaluation was performed for the shielding structure and location. The radiation dose based on the hole structure and location of the wall was evaluated. The shielding evaluation was performed to satisfy the safety standard for a normal person (1 μSv/h) and to use enough interior space. The MCNPX2.5 code was used and a dose evaluation was performed for the location of the shielding material, shielding structure, and hole structure. The evaluation result differs according to the shielding material location. The dose rate was small when the shielding material was positioned at the center. The dose evaluation result regarding the location of the shielding material was applied to the facility and the shielding thickness was determined (In 50 cm + Borax 5 cm + Out 45cm). In the existing hole structure, the radiation leak is higher than the standard. A hole structure model to prevent leakage of radiation was proposed. The general public dose limit was satisfied when using the concrete reinforcement and a zigzag structure. The shielding result will be of help to the facility shielding optimization.

Shielding structure analysis for LSDS facility

International Nuclear Information System (INIS)

Choi, Hong Yeop; Kim, Jeong Dong; Lee, Yong Deok; Kim, Ho Dong

2014-01-01

The nuclear material (Pyro, Spent nuclear fuel) itself and the target material to generate neutrons is the LSDS system for isotopic fissile assay release of high intensity neutron and gamma rays. This research was performed to shield from various strong radiation. A shielding evaluation was carried out with a facilities model of LSDS system. The MCNPX 2.5 code was used and a shielding evaluation was performed for the shielding structure and location. The radiation dose based on the hole structure and location of the wall was evaluated. The shielding evaluation was performed to satisfy the safety standard for a normal person (1 μSv/h) and to use enough interior space. The MCNPX2.5 code was used and a dose evaluation was performed for the location of the shielding material, shielding structure, and hole structure. The evaluation result differs according to the shielding material location. The dose rate was small when the shielding material was positioned at the center. The dose evaluation result regarding the location of the shielding material was applied to the facility and the shielding thickness was determined (In 50 cm + Borax 5 cm + Out 45cm). In the existing hole structure, the radiation leak is higher than the standard. A hole structure model to prevent leakage of radiation was proposed. The general public dose limit was satisfied when using the concrete reinforcement and a zigzag structure. The shielding result will be of help to the facility shielding optimization

Scanning high-Tc SQUID imaging system for magnetocardiography

International Nuclear Information System (INIS)

Yang, H-C; Wu, T-Y; Horng, H-E; Wu, C-C; Yang, S Y; Liao, S-H; Wu, C-H; Jeng, J T; Chen, J C; Chen, Kuen-Lin; Chen, M J

2006-01-01

A scanning magnetocardiography (MCG) system constructed from SQUID sensors offers potential to basic or clinical research in biomagnetism. In this work, we study a first order scanning electronic high-T c (HTS) SQUID MCG system for biomagnetic signals. The scanning MCG system was equipped with an x-y translation bed powered by step motors. Using noise cancellation and μ-metal shielding, we reduced the noise level substantially. The established scanning HTS MCG system was used to study the magnetophysiology of hypercholesterolaemic (HC) rabbits. The MCG data of HC rabbits were analysed. The MCG contour map of HC rabbits provides experimental models for the interpretation of human cardiac patterns

Development of neutron shielding material for cask

International Nuclear Information System (INIS)

Najima, K.; Ohta, H.; Ishihara, N.; Matsuoka, T.; Kuri, S.; Ohsono, K.; Hode, S.

2001-01-01

Since 1980's Mitsubishi Heavy Industries, Ltd (MHI) has established transport and storage cask design 'MSF series' which makes higher payload and reliability for long term storage. MSF series transport and storage cask uses new-developed neutron shielding material. This neutron shielding material has been developed for improving durability under high condition for long term. Since epoxy resin contains a lot of hydrogen and is comparatively resistant to heat, many casks employ epoxy base neutron shielding material. However, if the epoxy base neutron shielding material is used under high temperature condition for a long time, the material deteriorates and the moisture contained in it is released. The loss of moisture is in the range of several percents under more than 150 C. For this reason, our purpose was to develop a high durability epoxy base neutron shielding material which has the same self-fire-extinction property, high hydrogen content and so on as conventional. According to the long-time heating test, the weight loss of this new neutron shielding material after 5000 hours heating has been lower than 0.04% at 150 C and 0.35% at 170 C. A thermal test was also performed: a specimen of neutron shielding material covered with stainless steel was inserted in a furnace under condition of 800 C temperature for 30 minutes then was left to cool down in ambient conditions. The external view of the test piece shows that only a thin layer was carbonized

Direct {sup 99m}Tc labeling of Herceptin (trastuzumab) by {sup 99m}Tc(I) tricarbonyl ion

Energy Technology Data Exchange (ETDEWEB)

Chen, W.-J.; Yen, C.-L.; Lo, S.-T.; Chen, K.-T. [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lo, J.-M. [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan (China)], E-mail: jmlo@mx.nthu.edu.tw

2008-03-15

By simply incubating Herceptin (trastuzumab) with [{sup 99m}Tc(CO){sub 3}(OH{sub 2}){sub 3}]{sup +} ion in saline, a significant yield of {sup 99m}Tc-labeled trastuzumab was found to be achievable. The effective labeling may be based on that trastuzumab is inherent with endogenous histidine group to which {sup 99m}Tc(I) tricarbonyl ion can be strongly bound. For practical {sup 99m}Tc labeling processing, trastuzumab was purified beforehand from the commercial product, Herceptin (Genentech) via size exclusion chromatography to remove the excipient, {alpha}-histidine and a high-labeled yield could be obtained by incubating the purified trastuzumab with [{sup 99m}Tc(CO){sub 3}(OH{sub 2}){sub 3}]{sup +}. Retention of bioactivity of the {sup 99m}Tc(I)-labeled trastuzumab was validated using a cell binding test.

Radiation shielding application of lead glass

International Nuclear Information System (INIS)

Nathuram, R.

2017-01-01

Nuclear medicine and radiotherapy centers equipped with high intensity X-ray or teletherapy sources use lead glasses as viewing windows to protect personal from radiation exposure. Lead is the main component of glass which is responsible for shielding against photons. It is therefore essential to check the shielding efficiency before they are put in use. This can be done by studying photon transmission through the lead glasses. The study of photon transmission in shielding materials has been an important subject in medical physics and is potential useful in the development of radiation shielding materials

3-dimensional shielding design for a spallation neutron source facility in the high-intensity proton accelerator project

Energy Technology Data Exchange (ETDEWEB)

Tamura, Masaya; Maekawa, Fujio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2003-03-01

Evaluation of shielding performance for a 1 MW spallation neutron source facility in the Materials and Life Science Facility being constructed in the High-Intensity Proton Accelerator Project (J-PARC) is important from a viewpoint of radiation safety and optimization of arrangement of components. This report describes evaluated results for the shielding performance with modeling three-dimensionally whole structural components including gaps between them in detail. A Monte Carlo calculation method with MCNPX2.2.6 code and LA-150 library was adopted. Streaming and void effects, optimization of shield for cost reduction and optimization of arrangement of structures such as shutters were investigated. The streaming effects were investigated quantitatively by changing the detailed structure of components and gap widths built into the calculation model. Horizontal required shield thicknesses were ranged from about 6.5 m to 7.5 m as a function of neutron beam line angles. A shutter mechanism for a horizontal neutron reflectometer that was directed downward was devised, and it was shown that the shielding performance of the shutter was acceptable. An optimal biological shield configuration was finally determined according to the calculated results. (author)

Pharmaceutical design and pharmacological characterization of Tc99m [99mTc] labelled somatostatin and gastrin analogues

International Nuclear Information System (INIS)

Guggenberg, E. von

2004-10-01

The development of regulatory peptide analogues radiolabelled with 99m Tc is of great interest for nuclear medicine applications, as 99m Tc shows very favourable imaging characteristics, such as low radiation burden to the patient, optimal image quality in SPECT, one-day-acquisition-protocol, availability on demand and cost effectiveness. In this work the principles of pharmaceutical design and preclinical pharmacological characterization of regulatory peptide analogues labelled with 99m Tc with possible application in tumour diagnosis are described. [ 99m Tc-EDDA-HYNIC0,Tyr3]octreotide ( 99m Tc-EDDA-HYNIC-TOC) is a promising new radiopharmaceutical with the potential to replace [ 111 In-DTPA0]octreotide in receptor scintigraphy of somatostatin receptor-positive tumours. Radiolabelling at high labelling yields and high specific activities could be obtained applying a coligand exchange labelling approach from tricine for EDDA under optimized conditions of pH, EDDA and stannous ion concentration. The resulting complex was characterized via HPLC, receptor binding and LC-MS. For the development of a freeze-dried kit formulation with long shelf-life, high stability of the final preparation and retained biological activity, the addition of bulking agent, the pH of the freeze-drying solution and the content of stannous chloride were of major importance. Different methods of radiochemical purity testing were evaluated to guarantee high quality of the preparation in a clinical setting, forming the basis for a further clinical evaluation of this promising new radiopharmaceutical. Radiolabelling of [D-Glu1]minigastrin (MG) with 99m Tc was studied applying two different labelling approaches. HYNIC-MG could be labelled using tricine and EDDA as coligands; and (Nalpha-His)Ac-MG was used as tridentate ligand for the 99m Tc carbonyl core. Stability experiments by HPLC analysis in PBS, serum, histidine- and cysteine-solutions as well as rat liver and kidney homogenates, receptor

Effect of vanadium and yttrium doping on BSCCO superconductors

International Nuclear Information System (INIS)

Mohamed, S.B.; Halim, S.A.; Azhan, H.; Sidek, H.A.A; Tee, T.W.; Hassan, Z.A.

1999-01-01

The effect of vanadium and yttrium doping on the superconductivity is investigated. The doping was done on the calcium site ranging from x=0.00-0.10. The temperature dependence of electrical resistance and AC susceptibility measurements were made on these samples. The zero resistance for vanadium doped samples varied from 107 K (x = 0.00) to 68.5K (x = 0.10), whereas for yttrium doped samples it varied from 107 K (x = 0.00) to 54K (x 0.10). The volume fraction of the 2223 phase for both dopalit decreases witli increasing doping concentration. The nature of the temperature derivative of the resistance curves indicates the presence of a superconducting transition between grains coupled by weak links. The AC susceptibility data show enrichment of the volume fraction of the low Tc phase at higher compositions. The presence of low Tc phase (∼70 K) is visible in the susceptibility data. X-ray diffraction confirms the presence of mixed phases in the samples. (author)

The effect of current direction on superconducting properties of BSCCO fibres grown by an electrically assisted laser floating zone process

International Nuclear Information System (INIS)

Carrasco, M F; Amaral, V S; Vieira, J M; Silva, R F; Costa, F M

2006-01-01

The application of an electric current of 200 mA through the molten zone of BSCCO superconducting fibres during laser floating zone processing constitutes an upgrade for improving the grain alignment. When a direct electric current (positively polarized fibre) passes through the solidification interface, the solidification conditions approach equilibrium, favouring the development of a higher amount of 2212 and 14/24 stable phases. The new electrically assisted laser floating zone (EALFZ) technique also improves the 2223 phase formation in fibres heat treated at high temperatures (860 deg. C). However, the 2223 crystals grow perpendicularly to the fibre axis at the interface between the 2212 and 14/24 phases, crossing the crystals of the main phase responsible for the current transport, cancelling the alignment effect. The resultant current density and critical temperature values were J c 77 K = 230 A cm -2 and T c = 85 K, respectively. When a lower heat treatment temperature was accomplished (820 deg. C), the 2223 transverse crystals do not develop and a higher current density value of J c 77 K = 510 A cm -2 was achieved, although with a critical temperature of T c = 90 K

Correlation between differential renal uptake of 99mTc-MAG3 and 99mTc-DMSA

International Nuclear Information System (INIS)

Obaldo, J.M.; Gruenwald, F.; Menzel, C.; Biersack, H.J.

1994-01-01

We reviewed the quantitative indices obtained from sequential 99m Tc-MAG3 and 99m Tc-DMSA imaging studies performed in 134 patients with a variety of renal disorders in order to determine the correlation between the measured differential renal function using these two agents. Overall correlation was high with r=.86 and the derived regression equation was R.F. DMSA =8.2+0.84 (R.F. MAG3 ), where F.F. is the relative function. Highly divergent values for differential function were obtained however in some subjects. Patients with renal obstructive disorders had a correlation coefficient of.81 which was lower than those with nonobstructive pathologies (r=.95). Although relative kidney function measured using 99m Tc-MAG3 and 99m Tc-DMSA correlate significantly, certain patients such as those with renal obstruction may necessitate quantitation using different renal parameters. (orig.) [de

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

Science.gov (United States)

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

2017-05-10

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

Development of neutron shielding concrete containing iron content materials

Science.gov (United States)

Sariyer, Demet; Küçer, Rahmi

2018-02-01

Concrete is one of the most important construction materials which widely used as a neutron shielding. Neutron shield is obtained of interaction with matter depends on neutron energy and the density of the shielding material. Shielding properties of concrete could be improved by changing its composition and density. High density materials such as iron or high atomic number elements are added to concrete to increase the radiation resistance property. In this study, shielding properties of concrete were investigated by adding iron, FeB, Fe2B, stainless - steel at different ratios into concrete. Neutron dose distributions and shield design was obtained by using FLUKA Monte Carlo code. The determined shield thicknesses vary depending on the densities of the mixture formed by the additional material and ratio. It is seen that a combination of iron rich materials is enhanced the neutron shielding of capabilities of concrete. Also, the thicknesses of shield are reduced.

Tc7, a Tc1-hitch hiking transposon in Caenorhabditis elegans.

OpenAIRE

Rezsohazy, R; van Luenen, H G; Durbin, R M; Plasterk, R H

1997-01-01

We have found a novel transposon in the genome of Caenorhabditis elegans. Tc7 is a 921 bp element, made up of two 345 bp inverted repeats separated by a unique, internal sequence. Tc7 does not contain an open reading frame. The outer 38 bp of the inverted repeat show 36 matches with the outer 38 bp of Tc1. This region of Tc1 contains the Tc1-transposase binding site. Furthermore, Tc7 is flanked by TA dinucleotides, just like Tc1, which presumably correspond to the target duplication generated...

Ultra high molecular weight polyethylene (UHMWPE) fiber epoxy composite hybridized with Gadolinium and Boron nanoparticles for radiation shielding

Science.gov (United States)

Mani, Venkat; Prasad, Narasimha S.; Kelkar, Ajit

2016-09-01

Deep space radiations pose a major threat to the astronauts and their spacecraft during long duration space exploration missions. The two sources of radiation that are of concern are the galactic cosmic radiation (GCR) and the short lived secondary neutron radiations that are generated as a result of fragmentation that occurs when GCR strikes target nuclei in a spacecraft. Energy loss, during the interaction of GCR and the shielding material, increases with the charge to mass ratio of the shielding material. Hydrogen with no neutron in its nucleus has the highest charge to mass ratio and is the element which is the most effective shield against GCR. Some of the polymers because of their higher hydrogen content also serve as radiation shield materials. Ultra High Molecular Weight Polyethylene (UHMWPE) fibers, apart from possessing radiation shielding properties by the virtue of the high hydrogen content, are known for extraordinary properties. An effective radiation shielding material is the one that will offer protection from GCR and impede the secondary neutron radiations resulting from the fragmentation process. Neutrons, which result from fragmentation, do not respond to the Coulombic interaction that shield against GCR. To prevent the deleterious effects of secondary neutrons, targets such as Gadolinium are required. In this paper, the radiation shielding studies that were carried out on the fabricated sandwich panels by vacuum-assisted resin transfer molding (VARTM) process are presented. VARTM is a manufacturing process used for making large composite structures by infusing resin into base materials formed with woven fabric or fiber using vacuum pressure. Using the VARTM process, the hybridization of Epoxy/UHMWPE composites with Gadolinium nanoparticles, Boron, and Boron carbide nanoparticles in the form of sandwich panels were successfully carried out. The preliminary results from neutron radiation tests show that greater than 99% shielding performance was

Experimental Set-Up for Evaluation of Electro-Magnetic Characteristics of High-Tc Superconductors Cooled by Liquid Hydrogen

OpenAIRE

Shirai, Yasuyuki; Hikawa, Kyosuke; Shiotsu, Masahiro; Tatsumoto, Hideki; Hata, Koichi; Kobayashi, Hiroaki; Nonaka, Satoshi; Naruo, Yoshihiro; Inatani, Yoshifumi

2013-01-01

Liquid hydrogen (LH2) has excellent properties as a coolant, such as large latent heat, low viscosity coefficient, etc. Not only MgB2 but also other high-Tc superconductors are expected to have excellent properties when cooled by LH2. It is necessary for a stability design of a high-Tc superconductor cooled by LH2 to make an electro-magnetic characteristic clear. However, due to the handling difficulties of LH2, there are only few papers on the properties of LH2-cooled superconductors, especi...

Superconducting magnetic shields for neutral beam injectors. Final report

International Nuclear Information System (INIS)

1985-04-01

Large high energy deuterium neutral beams which must be made from negative ions require extensive magnetic shielding against the intense fringe fields surrounding a magnetic fusion power plant. The feasibility of shielding by multilayer sheets of copper-superconducting laminated material was investigated. It was found that, if necessary fabrication techniques are developed, intrinsically stable type II superconductors will be able to shield against the magnetic fields of the fusion reactors. Among the immediate benefits of this research is better magnetic shields for neutral beam injectors in support of DOE's fusion program. Another application may be in the space vehicles, where difficulties in transporting heavy μ-metal sections may make a comparatively light superconducting shield attractive. Also, as high-field superconducting magnets find widespread applications, the need for high-intensity magnetic shielding will increase. As a result, the commercial market for the magnetic shields should expand along with the market for superconducting magnets

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.

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.

Electrolytic 99mTcO4- reduction: a different pathway to obtain 99mTc-labelled compounds

International Nuclear Information System (INIS)

Savio, E.; Kremer, C.; Gambino, D.; Kremer, E.; Leon, A.

1991-01-01

Electrolytic reduction of 99m TcO 4 - at inert electrodes to obtain 99m Tc cationic complexes and in vitro stability of labelled compounds were studied. Amines were used as neutral N-donor ligands and a systematic analysis of various parameters involved in the reduction process was performed. Usefulness of electrolytic reduction was proved as an alternative 99m Tc-labelling method. Its most important advantages are: production of complexes with a high radiochemical purity, negligible presence of red-hyd- 99m Tc, lack of foreign materials, simplicity of development and possibility of further applications. (author)

Determination of Tc-99 in radioactive wastes

International Nuclear Information System (INIS)

Rivera S, A. A.

2015-01-01

Tc-99 is a fission product and one of the most important radionuclides from the view point of safety assessment for the disposal of radioactive waste because of its long half-life (2.1 x 10 5 years) and high mobility in soil-water systems, if this is released into the environment in significant quantities can concentrate on plants and animals. Tc-99 is a pure beta emitter with a maximum energy of 292 KeV, so their quantification imposes destructive methods to be analyzed by liquid scintillation. Therefore the quantification of Tc-99 in ion exchange resins requires of the mineralization of these and separation of Tc-99 of other radioisotopes present in the resin. Therefore the object of this thesis is to develop a quantification method of Tc-99 content in spent exchange resins. So in order to track the behavior of technetium during digestion exchange resins and radiochemical separation, given its high volatility, in this work the 99m Tc is used. To determine the degree of mineralization of the resins, an analysis was performed by chromatography. Subsequently the method used to determine the percentage of 99m Tc aerosolized during mineralization of resin is described. After the method for the radiochemical separation of 99m Tc is presented by liquid-liquid extraction using crown ether as extractant; for this testing was performed by varying the molarity of the extractant, the ratio of solvent extractant, type of digestion of the resin and the presence of Sr-85, in order to study the behavior of 99m Tc in the presence of this radioisotope. Finally, a track beta spectra of a sample of 99m Tc eluted from a generator 99 Mo/ 99m Tc function of time was performed. (Author)

Isomeric and high-spin states of 94Tc and the search for yrast isomers near N~50

Science.gov (United States)

Lee, I. Y.; Johnson, N. R.; McGowan, F. K.; Young, G. R.; Guidry, M. W.; Yates, S. W.

1981-07-01

A search for isomers in the N~50 region has produced no evidence of high-spin yrast isomerism. A new 4.5-ns low-multiplicity isomer has been identified and assigned to 94Tc, while the yrast sequence of 94Tc has been established to more than 5 MeV in excitation energy. [NUCLEAR REACTIONS 76Ge, 78Se(20Ne,xnypγ), E=80.9 MeV, 89Y, 93Nb(10B,xnypγ), E=52.0,58.4,62.8 MeV; measured Eγ, Iγ, γ-γ prompt and delayed coin, γ-X coin; deduced levels, t12 of 94Tc isomer, yrast states.

Conductus makes high-Tc integrated circuit

International Nuclear Information System (INIS)

Anon.

1991-01-01

This paper reports that researchers at Conductus have successfully demonstrated what the company says is the world's first integrated circuit containing active devices made from high-temperature superconductors. The circuit is a SQUID magnetometer made from seven layers of material: three layers of yttrium-barium-copper oxide, two layers of insulating material, a seed layer to create grain boundaries for the Josephson junctions, and a layer of silver for making electrical contact to the device. The chip also contains vias, or pathways that make a superconducting contact between the superconducting layers otherwise separated by insulators. Conductus had previously announced the development of a SQUID magnetometer that featured a SQUID sensor and a flux transformer manufactured on separate chips. What makes this achievement important is that the company was able to put both components on the same chip, thus creating a simple integrated circuit on a single chip. This is still a long way from conventional semiconductor technology, with as many as a million components per chip, or even the sophisticated low-Tc superconducting chips made by the Japanese, but the SQUID magnetometer demonstrates all the elements and techniques necessary to build more complex high-temperature superconductor integrated circuits, making this an important first step

Five-fold way to new high Tc superconductors

Indian Academy of Sciences (India)

shook the foundation of phonon-mediated pairing mechanism. In fact, certain in- ...... of superconducting Tc in doped cuprates below optimal doping. ...... ductor transition, the following are the minimal requirements for superconductivity:.

High-Tc SQUID Application for Roll to Roll Metallic Contaminant Detector

International Nuclear Information System (INIS)

Tanaka, S.; Kitamura, Y.; Uchida, Y.; Hatsukade, Y.; Ohtani, T.; Suzuki, S.

2012-01-01

A sensitive eight-channel high-Tc Superconducting Interference Device (SQUID) detection system for magnetic contaminant in a lithium ion battery anode was developed. Finding ultra-small metallic foreign matter is an important issue for a manufacturer because metallic contaminants carry the risk of an internal short. When contamination occurs, the manufacturer of the product suffers a great loss from recalling the tainted product. Metallic particles with outer dimensions smaller than 100 microns cannot be detected using a conventional X-ray imaging system. Therefore, a highly sensitive detection system for small foreign matter is required. We have already developed a detection system based on a single-channel SQUID gradiometer and horizontal magnetization. For practical use, the detection width of the system should be increased to at least 65 mm by employing multiple sensors. In this paper, we present an 8-ch high-Tc SQUID roll-to-roll system for inspecting a lithium-ion battery anode with a width of 65 mm. A special microscopic type of a cryostat was developed upon which eight SQUID gradiometers were mounted. As a result, small iron particles of 35 microns on a real lithium-ion battery anode with a width of 70 mm were successfully detected. This system is practical for the detection of contaminants in a lithium ion battery anode sheet.

Synthesis and evaluation of 99mTc/99Tc-MAG3-biotin conjugates for antibody pretargeting strategies

International Nuclear Information System (INIS)

Gog, Frank B. van; Visser, Gerard W.M.; Gowrising, Radjish W.A.; Snow, Gordon B.; Dongen, Guus A.M.S. van

1998-01-01

Four 99m Tc-MAG3-biotin conjugates were synthesized to determine their potential use in antibody pretargeting strategies for radioimmunoscintigraphy (RIS). To use these 99m Tc-MAG3-biotin conjugates as model compounds for 186 Re-MAG3-biotin conjugates for radioimmunotherapy (RIT), nanomolar amounts of 99 Tc were added as carrier to 99m Tc. The biotin derivatives used for the preparation of the conjugates - biocytin, biotin hydrazide, biotinyl-piperazine, and biotinyl-diaminosuccinic acid - differed at the site that is regarded to be susceptible to hydrolysis by biotinidase present in human plasma. All four conjugates were produced with high radiochemical purity, were stable in PBS, and demonstrated full binding capacity to streptavidin. The 99m Tc/ 99 Tc-MAG3-labeled biotinyl-piperazine and biotinyl-diaminosuccinic acid conjugates were stable in mouse as well as human plasma, whereas the corresponding biocytin and biotin hydrazide conjugates were rapidly degraded. The biodistribution in nude mice at 30 min after injection was similar for all conjugates, and a rapid blood clearance and high intestinal excretion were both observed. It is concluded that the metabolic routing of a conjugate containing biotin and MAG3 is dominated by these two moieties. For this reason, MAG3-biotin conjugates do not seem suited for pretargeted RIT, for which quantitative and fast renal excretion is a prerequisite to minimize radiation toxicity. However, in a pretargeted RIS approach the 99m Tc-MAG3-biotin conjugates might have potential

Shielding considerations for an electron linear accelerator complex for high energy physics and photonics research

International Nuclear Information System (INIS)

Holmes, J.A.; Huntzinger, C.J.

1987-01-01

Radiation shielding considerations for a major high-energy physics and photonics research complex which comprise a 50 MeV electron linear accelerator injector, a 1.0 GeV electron linear accelerator and a 1.3 GeV storage ring are discussed. The facilities will be unique because of the close proximity of personnel to the accelerator beam lines, the need to adapt existing facilities and shielding materials and the application of strict ALARA dose guidelines while providing maximum access and flexibility during a phased construction program

Enhanced 99 Tc retention in glass waste form using Tc(IV)-incorporated Fe minerals

Energy Technology Data Exchange (ETDEWEB)

Um, Wooyong; Luksic, Steven A.; Wang, Guohui; Saslow, Sarah; Kim, Dong-Sang; Schweiger, Michael J.; Soderquist, Chuck Z.; Bowden, Mark E.; Lukens, Wayne W.; Kruger, Albert A.

2017-11-01

Technetium (99Tc) immobilization by doping into iron oxide mineral phases may alleviate the problems with Tc volatility during vitrification of nuclear waste. Reduced Tc, Tc(IV), substitutes for Fe(III) in the crystal structure by a process of Tc reduction from Tc(VII) to Tc(IV) followed by co-precipitation of Fe oxide minerals. Two Tc-incorporated Fe minerals (Tc-goethite and Tc-magnetite/maghemite) were prepared and tested for Tc retention in glass melt samples at temperatures between 600 – 1,000 oC. After being cooled, the solid glass specimens prepared at different temperatures were analyzed for Tc oxidation state using Tc K-edge XANES. In most samples, Tc was partially oxidized from Tc(IV) to Tc(VII) as the melt temperature increased. However, Tc retention in glass melt samples prepared using Tc-incorporated Fe minerals were moderately higher than in glass prepared using KTcO4 because of limited and delayed Tc volatilization.

Triamide mercaptide (N/sub 3/S) ligands for Tc-99m as potential Tc-99m renal function agents

International Nuclear Information System (INIS)

Fritzberg, A.R.; Kasina, S.; Johnson, D.L.; Eshima, D.

1985-01-01

A number of diamide dimercaptide (N/sub 2/S/sub 2/) complexes of Tc-99m have shown potential as renal tubular function radiopharmaceuticals that could replace radioiodinated hippurate (OIH). Evaluation of such ligands suggested that maximum efficiency for tubular secretion and specificity resulted from addition of a carboxylate group. However, such derivatives resulted in chelate ring stereoisomers that were differently transported by the renal tubular system. The problem of stereoisomers was obviated by replacing one sulfur with an effectively planar amido nitrogen. Groups on the nitrogen then result in diastereomers only when an additional asymetric center is present. A series of triamide mercaptide compounds have been synthesized to evaluate this class as ligands for Tc-99m. One of the simplest of the series, mercaptoacetylglycylglycylglycine (MAG/sub 3/), formed a single Tc-99m product in high yield as determined by HPLC. Preliminary results with pmr and ms of the Tc-99 complex indicate a structure consistent with a 1:1 metal to ligand ratio and monooxo technetium group. Biological evaluation of Tc-99m MAG/sub 3/ showed high renal specificity and rate of excretion exceeding OIH in several species including humans. Members of the N/sub 3/S series studied include mercaptoacetylglycylglycyl-amino acids. In some cases with second asymmetric centers, two components were seen on HPLC. In mice several dianionic Tc-99m complexes were excreted faster than OIH, Tc-99m MAG/sub 2/-ala, -asn, and -gln. Trianionic Tc-99m MAG/sub 2/-asp and -glu were excreted more slowly, and Tc-99m MAG/sub 2/-phe showed hepatobiliary excretion. Triamide mercaptides represent a new ligand class for Tc-99m

Design of piezoelectric transducer layer with electromagnetic shielding and high connection reliability

Science.gov (United States)

Qiu, Lei; Yuan, Shenfang; Shi, Xiaoling; Huang, Tianxiang

2012-07-01

Piezoelectric transducer (PZT) and Lamb wave based structural health monitoring (SHM) method have been widely studied for on-line SHM of high-performance structures. To monitor large-scale structures, a dense PZTs array is required. In order to improve the placement efficiency and reduce the wire burden of the PZTs array, the concept of the piezoelectric transducers layer (PSL) was proposed. The PSL consists of PZTs, a flexible interlayer with printed wires and signal input/output interface. For on-line SHM on real aircraft structures, there are two main issues on electromagnetic interference and connection reliability of the PSL. To address the issues, an electromagnetic shielding design method of the PSL to reduce spatial electromagnetic noise and crosstalk is proposed and a combined welding-cementation process based connection reliability design method is proposed to enhance the connection reliability between the PZTs and the flexible interlayer. Two experiments on electromagnetic interference suppression are performed to validate the shielding design of the PSL. The experimental results show that the amplitudes of the spatial electromagnetic noise and crosstalk output from the shielded PSL developed by this paper are - 15 dB and - 25 dB lower than those of the ordinary PSL, respectively. Other two experiments on temperature durability ( - 55 °C-80 °C ) and strength durability (160-1600μɛ, one million load cycles) are applied to the PSL to validate the connection reliability. The low repeatability errors (less than 3% and less than 5%, respectively) indicate that the developed PSL is of high connection reliability and long fatigue life.

On characteristic voltage of the high Tc superconductor. [Y-Ba-Cu-O

Energy Technology Data Exchange (ETDEWEB)

Vasiliev, B V; Uchaikin, S V [Joint Inst. for Nuclear Research, Low Temperature Physics Dept., Dubna (USSR)

1991-12-01

The critical currents and normal resistances of the small bridges from yttrium-based high-Tc superconducting ceramics have been measured. The characteristic voltage of these bridges was found to be approximately 20{mu}V. This effect can be explained if between the ceramic grains there are contacts of an order of one crystalline cell in size. (orig.).

A study on the development of high Tc superconducting materials and on the effects of neutron irradiation

International Nuclear Information System (INIS)

Won, Dong Yeon; Chang, In Soon; Lee, Jong Min

1990-08-01

An Ag-sheathed (Pb,Bi)SrCaCuO superconducting tape was prepared by the cold rolling and post heat treatment method. The tape shows a c-oriented texture perpendicular to the rolling direction. The aligned grain structure may be resulted from the anisotropic grain growth of the high Tc superconducting phase. The bulk (Pb,Bi)SrCaCuO samples with (a) Tc=10lK and (b) 96K were prepared by the solid state reaction method and were neutron-irradiated up to 1.5 x 10 1 8 n/cm 2 . After irradiation the zero resistance temperature(Tc) of (a) was decreased to 96K but (b) did not show any change in Tc. The critical current density of (a) also decreased from 0.75A/cm 2 but (b) was constant as 1.5 A/cm 2 after irradiation. (Author)

Enhanced conductive loss in nickel–cobalt sulfide nanostructures for highly efficient microwave absorption and shielding

Science.gov (United States)

Li, Wanrong; Zhou, Min; Lu, Fei; Liu, Hongfei; Zhou, Yuxue; Zhu, Jun; Zeng, Xianghua

2018-06-01

Microwave-absorbing materials with light weight and high efficiency are desirable in addressing electromagnetic interference (EMI) problems. Herein, a nickel–cobalt sulfide (NCS) nanostructure was employed as a robust microwave absorber, which displayed an optimized reflection loss of  ‑49.1 dB in the gigahertz range with a loading of only 20 wt% in an NCS/paraffin wax composite. High electrical conductivity was found to contribute prominent conductive loss in NCS, leading to intense dielectric loss within a relatively low mass loading. Furthermore, owing to its high electrical conductivity and remarkable dielectric loss to microwaves, the prepared NCS exhibited excellent performance in EMI shielding. The EMI shielding efficiency of the 50 wt% NCS/paraffin composite exceeded 55 dB at the X-band, demonstrating NCS is a versatile candidate for solving EMI problems.

Comparative binding characteristics of Tc-CPI, Tc-TBI, and Tc-MIBI in cultured heart cells: Correlation with biochemical analysis and animal images

International Nuclear Information System (INIS)

Piwnica-Worms, D.; Kronauge, J.F.; Holman, B.L.; Davison, A.; Jones, A.G.

1987-01-01

Hexakis (isonitrile)technetium (I) complexes are a new class of cationic, lipophilic myocaridal perfusion imaging agents. To better understand their cellular mechanisms of uptake and washout, chick heart cells grown in culture were used as a model myocardial system. Tc-MIBI showed uptake to a plateau at a rate similar to Tc-CPI (t1/2 = 4.1 +- 0.7 minutes); however, the plateau was 63% greater. Tc-TBI uptake approached a plateau 900% greater than Tc-CPI binding. Heart cell studies showed washout of Tc-CPI>Tc-TBI>Tc-MIBI, which correlated with kinetic analysis of rabbit myocardial images. Biochemical in vitro analysis in human plasma demonstrated 75% enzymatic ester hydrolysis of Tc-CPI by 3 minutes, but no hydrolysis of Tc-TBI and Tc-MIBI. The results suggest that metabolism of the ester function of Tc-CPI following myocardial uptake may in part account for the more rapid cellular washout rates of Tc-CPI compared with Tc-TBI and Tc-MIBI

Shielding concerns at a spallation source

International Nuclear Information System (INIS)

Russell, G.J.; Robinson, H.; Legate, G.L.; Woods, R.

1989-01-01

Neutrons produced by 800-MeV proton reactions at the Los Alamos Neutron Scattering Center spallation neutron source cause a variety of challenging shielding problems. We identify several characteristics distinctly different from reactor shielding and compute the dose attenuation through an infinite slab/shield composed of iron (100 cm) and borated polyethylene (15 cm). Our calculations show that (for an incident spallation spectrum characteristic of neutrons leaking from a tungsten target at 90/degree/) the dose through the shield is a complex mixture of neutrons and gamma rays. High-energy (> 20 MeV) neutron production from the target is ≅5% of the total, yet causes ≅68% of the dose at the shield surface. Primary low-energy (< 20 MeV) neutrons from the target contribute negligibly (≅0.5%) to the dose at the shield surface yet cause gamma rays, which contribute ≅31% to the total dose at the shield surface. Low-energy neutrons from spallation reactions behave similarly to neutrons with a fission spectrum distribution. 6 refs., 8 figs., 1 tab

The diffusion coefficient for 239Pu, 241Am, 99Tc and 137Cs in highly compacted buffer materials

International Nuclear Information System (INIS)

Zhou Kanghan; Li Guoding

1998-01-01

Based on one-dimension diffusion model, the diffusion coefficients of Pu, Am, Tc and Cs in highly compacted sodium-bentonite generally used as buffer materials in geologic disposal system for high-level radioactive waste have been determined at room temperature in the atmosphere of nitrogen. The results show that the diffusion coefficients of Am, Pu and Tc and about 10 -13 ∼10 -15 m 2 /s, and that of Cs about 10 -12 m 2 /s. The diffusion coefficients of these elements decrease with the increasing of the dry density of buffer materials. From the relationship of diffusion coefficient, retardation coefficient and dry density of bentonite, it has been concluded that Am and Pu transfer predominately by diffusion in solid phase, however, Cs and Tc by diffusion in pore water

Epitaxial effects in thin films of high-Tc cuprates with the K2NiF4 structure

Science.gov (United States)

Naito, Michio; Sato, Hisashi; Tsukada, Akio; Yamamoto, Hideki

2018-03-01

La2-xSrxCuO4 (LSCO) and La2-xBaxCuO4 (LBCO) have been recognized as the archetype materials of "hole-doped" high-Tc superconductors. Their crystal structures are relatively simple with a small number of constituent cation elements. In addition, the doping level can be varied by the chemical substitution over a wide range enough to obtain the full spectrum of doping-dependent electronic and magnetic properties. These attractive features have dedicated many researchers to thin-film growth of LSCO and LBCO. The critical temperature (Tc) of LSCO and LBCO is sensitive to strain as manifested by a positive pressure coefficient of Tc in bulk samples. In general, films are strained if they are grown on lattice-mismatched substrates (epitaxial strain). Early attempts (before 1997) at the growth of LSCO and LBCO films resulted in depressed Tc below 30 K as they were grown on a commonly used SrTiO3 substrate (in-plane lattice parameter asub = 3.905 Å): the in-plane lattice parameters of LSCO and LBCO are ≤3.80 Å, and hence tensile epitaxial strain is introduced. The situation was changed by the use of LaSrAlO4 substrates with a slightly shorter in-plane lattice constant (asub = 3.756 Å). On LaSrAlO4 substrates, the Tc reaches 45 K in La1.85Sr0.15CuO4, 47 K in La1.85Ba0.15CuO4, and 56 K in ozone-oxidized La2CuO4+δ films, substantially higher than the Tc's of the bulk compounds. The Tc increase in La1.85Sr0.15CuO4 films on LaSrAlO4 and decrease on SrTiO3 are semi-quantitatively in accord with the phenomenological estimations based on the anisotropic strain coefficients of Tc (dTc/dεi). In this review article, we describe the growth and properties of films of cuprates having the K2NiF4 structure, mainly focusing on the increase/decrease of Tc by epitaxial strain and quasi-stable phase formation by epitaxial stabilization. We further extract the structural and/or physical parameters controlling Tc toward microscopic understanding of the variation of Tc by epitaxial strain.

Tc Chemistry in HLW: Role of Organic Complexants

International Nuclear Information System (INIS)

Hess, Nancy S.; Conradsen, Steven D.

2003-01-01

Tc complexation with organic compounds in tank waste plays a significant role in the redox chemistry of Tc and the partitioning of Tc between the supernatant and sludge components in waste tanks. These processes need to be understood so that strategies to effectively remove Tc from high-level nuclear waste prior to waste immobilization can be developed and so that long-term consequences of Tc remaining in residual waste after sludge removal can be evaluated. Only limited data on the stability of Tc-organic complexes exists and even less thermodynamic data on which to develop predictive models of Tc chemical behavior is available. To meet these challenges we are conducting a research program to study to develop thermodynamic data on Tc-organic complexation over a wide range of chemical conditions. We will attempt to characterize Tc-speciation in actual tank waste using state-of-the-art analytical organic chemistry, separations, and speciation techniques to validate our model. On the basis of such studies we will develop credible model of Tc chemistry in HLW that will allow prediction of Tc speciation in tank waste and Tc behavior during waste pretreatment processing and in waste tank residuals

99mTc-MAG3: can it be a viable alternative to 99mTc-DTPA ?

International Nuclear Information System (INIS)

Bal, C.S.; Padhy, A.K.; Nair, R.; Gopinath, P.G.

1991-01-01

The purpose of this study was to assess the potentials of 99m Tc MAG 3 to replace universally used 99m Tc-DTPA as a routine renal agent. Five patients with different nephrological problems were first studied with 99m Tc MAG 3 and then reinvestigated with 99m Tc-DTPA two to seven days later. Renal MAG 3 gamma camera images were found to be almost identical with those of 99m Tc-DTPA images except high hepatic and splenic uptake of the former compound in four out of five patients (80%) irrespective of kidney function. MAG 3 and DTPA renograms showed identical differential renal uptake function (r=0.87) with slightly higher uptake in right kidneys. Time to reach the peak correlated well (r=0.91). Time to reach half maximum renal activity was also found to be almost identical (r=0.97) for MAG 3 and DTPA. It was felt that the age old 99m Tc-DTPA is as good a compound as 99m Tc MAG 3 with regard to imaging and assessment of renal uptake, drainage and differential renal functions. 99m Tc-DTPA is much cheaper, readily available in India and stable to suit the logistics in a busy nuclear medicine department for routine renography. (author). 10 refs., 2 figs., 3 tabs

New level schemes with high-spin states of 105,107,109Tc

International Nuclear Information System (INIS)

Luo, Y.X.; Rasmussen, J.O.; Lee, I.Y.; Fallon, P.; Hamilton, J.H.; Ramayya, A.V.; Hwang, J.K.; Gore, P.M.; Zhu, S.J.; Wu, S.C.; Ginter, T.N.; Ter-Akopian, G.M.; Daniel, A.V.; Stoyer, M.A.; Donangelo, R.; Gelberg, A.

2004-01-01

New level schemes of odd-Z 105,107,109 Tc are proposed based on the 252 Cf spontaneous-fission-gamma data taken with Gammasphere in 2000. Bands of levels are considerably extended and expanded to show rich spectroscopic information. Spin/parity and configuration assignments are made based on determinations of multipolarities of low-lying transitions and the level analogies to the previously reported levels, and to those of the neighboring Rh isotopes. A non-yrast negative-parity band built on the 3/2 - [301] orbital is observed for the first time in 105 Tc. A positive-parity band built on the 1/2 + [431] intruder orbital originating from the π(g 7/2 /d 5/2 ) subshells and having a strong deformation-driving effect is observed for the first time in 105 Tc, and assigned in 107 Tc. A positive-parity band built on the excited 11/2 + level, which has rather low excitation energy and predominantly decays into the 9/2 + level of the ground state band, provides evidence of triaxiality in 107,109 Tc, and probably also in 105 Tc. Rotational constants are calculated and discussed for the K=1/2 intruder bands using the Bohr-Mottelson formula. Level systematics are discussed in terms of the locations of proton Fermi levels and deformations. The band crossings of yrast positive-parity bands are observed, most likely related to h 11/2 neutron alignment. Triaxial-rotor-plus-particle model calculations performed with ε=0.32 and γ=-22.5 deg. on the prolate side of maximum triaxiality yielded the best reproduction of the excitation energies, signature splittings, and branching ratios of the positive-parity bands (except for the intruder bands) of these Tc isotopes. The significant discrepancies between the triaxial-rotor-plus-particle model calculations and experiment for the K=1/2 intruder bands in 105,107 Tc need further theoretical studies

99mTc renal tubular function agents: Current status

International Nuclear Information System (INIS)

Eshima, D.; Fritzberg, A.R.; Taylor, A. Jr.

1990-01-01

Orthoiodohippuric (OIH) acid labeled with 131I is a widely used renal radiopharmaceutical agent and has been the standard radiopharmaceutical agent for the measurement of effective renal plasma flow (EPRF). Limitations to the routine clinical use of 131I OIH are related to the suboptimal imaging properties of the 131I radionuclide and its relatively high radiation dose. 123I has been substituted for 131I; however, its high cost and short shelf-life have limited its widespread use. Recent work has centered on the development of a new 99mTc renal tubular function agent, which would use the optimal radionuclidic properties and availability of 99mTc and combine the clinical information provided by OIH. The search for a suitable 99mTc renal tubular function agent has focused on the diamide dithiolate (N2S2), the paraaminohippuric iminodiacetic acid (PAHIDA), and the triamide mercaptide (N3S) donor ligand systems. To date, the most promising 99mTc tubular function agent is the N3S complex: 99mTc mercaptoacetyltriglycine (99mTc MAG3). Studies in animal models in diuresis, dehydration, acid or base imbalance, ischemia, and renal artery stenosis demonstrate that 99mTc MAG3 behaves similarly to 131I OIH. A simple kit formulation is available that yields the 99mTc MAG3 complex in high radiochemical purity. Studies in normal subjects and patients indicate that 99mTc MAG3 is an excellent 99mTc renal tubular agent, but its plasma clearance is only 50% to 60% that of OIH. In an effort to develop an improved 99mTc renal tubular function agent, changes have been made in the core N3S donor ligand system, but to date no agent has been synthesized that is clinically superior to 99mTc MAG3. 61 references

Bioaccumulation and chemical modification of Tc by soil bacteria

International Nuclear Information System (INIS)

Henrot, J.

1989-01-01

Bioaccumulation and chemical modification of pertechnetate (TcO 4 -) by aerobically and anaerobically grown soil bacteria and by pure cultures of sulfate-reducing bacteria (Desulfovibrio sp.) were studied to gain insight on the possible mechanisms by which bacteria can affect the solubility of Tc in soil. Aerobically grown bacteria had no apparent effect on TcO 4 -; they did not accumulate Tc nor modify its chemical form. Anaerobically grown bacteria exhibited high bioaccumulation and reduced TcO 4 -, enabling its association with organics of the growth medium. Reduction was a metabolic process and not merely the result of reducing conditions in the growth medium. Association of Tc with bacterial polysaccharides was observed only in cultures of anaerobic bacteria. Sulfate-reducing bacteria efficiently removed Tc from solution and promoted its association with organics. Up to 70% of the total Tc in the growth medium was bioaccumulated and/or precipitated. The remaining Tc in soluble form was entirely associated with organics. Pertechnetate was not reduced by the same mechanism as dissimilatory sulfate reduction, but rather by some reducing agent released in the growth medium. A calculation of the amount of Tc that could be associated with the bacterial biomass present in soil demonstrates that high concentration ratios in cultures do not necessarily imply that bioaccumulation is an important mechanism for long-term retention of Tc in soil

Shielding experiments with high-energy heavy ions for spaceflight applications

International Nuclear Information System (INIS)

Zeitlin, C; Guetersloh, S; Heilbronn, L; Miller, J; Elkhayari, N; Empl, A; LeBourgeois, M; Mayes, B W; Pinsky, L; Christl, M; Kuznetsov, E

2008-01-01

Mitigation of radiation exposures received by astronauts on deep-space missions must be considered in the design of future spacecraft. The galactic cosmic rays (GCR) include high-energy heavy ions, many of which have ranges that exceed the depth of shielding that can be launched in realistic scenarios. Some of these ions are highly ionizing (producing a high dose per particle) and for some biological endpoints are more damaging per unit dose than sparsely ionizing radiation. The principal physical mechanism by which the dose and dose equivalent delivered by these particles can be reduced is nuclear fragmentation, the result of inelastic collisions between nuclei in the hull of the spacecraft and/or other materials. These interactions break the incident ions into lighter, less ionizing and less biologically effective particles. We have previously reported the tests of shielding effectiveness using many materials in a 1 GeV nucleon -1 56 Fe beam, and also reported results using a single polyethylene (CH 2 ) target in a variety of beam ions and energies up to 1 GeV nucleon -1 . An important, but tentative, conclusion of those studies was that the average behavior of heavy ions in the GCR would be better simulated by heavy beams at energies above 1 GeV nucleon -1 . Following up on that work, we report new results using beams of 12 C, 28 Si and 56 Fe, each at three energies, 3, 5 and 10 GeV nucleon -1 , on carbon, polyethylene, aluminium and iron targets

Shielding experiments with high-energy heavy ions for spaceflight applications

Energy Technology Data Exchange (ETDEWEB)

Zeitlin, C; Guetersloh, S; Heilbronn, L; Miller, J [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Elkhayari, N; Empl, A; LeBourgeois, M; Mayes, B W; Pinsky, L [Physics Department, University of Houston, Houston, TX (United States); Christl, M [NASA Marshall Spaceflight Center, Huntsville, AL (United States); Kuznetsov, E [Physics Department, University of Alabama, Huntsville, AL (United States)], E-mail: cjzeitlin@lbl.gov

2008-07-15

Mitigation of radiation exposures received by astronauts on deep-space missions must be considered in the design of future spacecraft. The galactic cosmic rays (GCR) include high-energy heavy ions, many of which have ranges that exceed the depth of shielding that can be launched in realistic scenarios. Some of these ions are highly ionizing (producing a high dose per particle) and for some biological endpoints are more damaging per unit dose than sparsely ionizing radiation. The principal physical mechanism by which the dose and dose equivalent delivered by these particles can be reduced is nuclear fragmentation, the result of inelastic collisions between nuclei in the hull of the spacecraft and/or other materials. These interactions break the incident ions into lighter, less ionizing and less biologically effective particles. We have previously reported the tests of shielding effectiveness using many materials in a 1 GeV nucleon{sup -1} {sup 56}Fe beam, and also reported results using a single polyethylene (CH{sub 2}) target in a variety of beam ions and energies up to 1 GeV nucleon{sup -1}. An important, but tentative, conclusion of those studies was that the average behavior of heavy ions in the GCR would be better simulated by heavy beams at energies above 1 GeV nucleon{sup -1}. Following up on that work, we report new results using beams of {sup 12}C, {sup 28}Si and {sup 56}Fe, each at three energies, 3, 5 and 10 GeV nucleon{sup -1}, on carbon, polyethylene, aluminium and iron targets.

Towards kit formulation of 99mTc labelled somatostatin receptor binding peptides of high specific activity for tumour localization

International Nuclear Information System (INIS)

Behe, M.; Powell, P.; Maecke, H.R.

2001-01-01

The project aimed to develop 99m Tc octreotide analogue for use in nuclear oncology. Several attempts to label SRIF analogues with 99m Tc have used a direct labelling approach but, for this project, HYNIC was chosen as a technetium ligand. A comparison of two different SRIF analogues designed for high specific activity labelling with 99m Tc was done. HYNIC-Octreotide and HYNIC-TOC were prepared and a kit formulation that can be labelled conveniently is currently being studied in a clinical setting. (author)

Radiation shielding and dose rate distribution for the building of the high dose rate accelerator

International Nuclear Information System (INIS)

Matsuda, Koji; Takagaki, Torao; Nakase, Yoshiaki; Nakai, Yohta.

1984-03-01

A high dose rate electron accelerator was established at Osaka Laboratory for Radiation Chemistry, Takasaki Establishment, JAERI in the fiscal year of 1975. This report shows the fundamental concept for the radiation shielding of the accelerator building and the results of their calculations which were evaluated through the model experiments. After the construction of the building, the leak radiation was measured in order to evaluate the calculating method of radiation shielding. Dose rate distribution of X-rays was also measured in the whole area of the irradiation room as a data base. (author)

Design and setup of a portable stirring device for transfer and dissolution of 99Mo applied to the use of a 99mTc generator

International Nuclear Information System (INIS)

Lopez, Yon; Rojas, Jorge

2014-01-01

This work shows the design and implementation of a portable magnetic stirring device for transfer and efficient dissolution of Mo O 3 coupled to a 99m Tc generator prototype. The development of this equipment will enable an efficient and safe transfer of 99 Mo at a 2 Ci of maximum activity from the nuclear reactor Huarangal to the point of operation of the 99m Tc generator equipment. This article describes the mechanical design, volume and shielding calculation, the electronics design and the programmable speed control of the stirring system for radioactive samples. (authors).

Recrystallization of high temperature superconductors

Energy Technology Data Exchange (ETDEWEB)

Kouzoudis, Dimitris [Iowa State Univ., Ames, IA (United States)

1996-05-09

Currently one of the most widely used high T_c superconductors is the Bi-based compounds Bi₂Sr₂CaCu₂O_z and Bi₂Sr₂Ca₂Cu₃O_z (known as BSCCO 2212 and 2223 compounds) with T_c values of about 85 K and 110 K respectively. Lengths of high performance conductors ranging from 100 to 1000 m long are routinely fabricated and some test magnets have been wound. An additional difficulty here is that although Bi-2212 and Bi-2223 phases exist over a wide range of stoichiometries, neither has been prepared in phase-pure form. So far the most successful method of constructing reliable and robust wires or tapes is the so called powder-in-tube (PIT) technique [1, 2, 3, 4, 5, 6, 7] in which oxide powder of the appropriate stoichiometry and phase content is placed inside a metal tube, deformed into the desired geometry (round wire or flat tape), and annealed to produce the desired superconducting properties. Intermediate anneals are often incorporated between successive deformation steps. Silver is the metal used in this process because it is the most compatible with the reacting phase. In all of the commercial processes for BSCCO, Ag seems to play a special catalytic role promoting the growth of high performance aligned grains that grow in the first few micrometers near the Ag/BSCCO interface. Adjacent to the Ag, the grain alignment is more perfect and the current density is higher than in the center of the tape. It is known that Ag lowers the melting point of several of the phases but the detailed mechanism for growth of these high performance grains is not clearly understood. The purpose of this work is to study the nucleation and growth of the high performance material at this interface.

Processing and critical currents of high-Tc superconductor wires

International Nuclear Information System (INIS)

Krauth, H.; Heine, K.; Tenbrink, J.

1991-01-01

High-Tc superconductors are expected to have a major impact on magnet and energy technology. For technical applications they have to fulfill the requirement of carrying sufficient current at a critical current density of the order of 10 5 A/cm 2 at operating temperature and magnetic field. At 77 K these values have not been achieved yet in bulk material or wires due to weak link problems and flux creep effects. Progress made so far and remaining problems will be discussed in detail concentrating on problems concerning development of technical wires. In Bi-based materials technically interesting critical current densities could be achieved at 4.2 K in fields above 20 T (1,2), rendering possible the use of such material for very high field application. (orig.)

The Effect of Twins on Critical Currents of High Tc Superconductors

Science.gov (United States)

1989-01-01

particles to stick together due to electrostatic forces. To overcome this we have formed a slurry of the material in liquid nitrogen and flash...can use and the liquid convection tends to counteract the separation process. We have-now designed a magnetic track which particles will slide down with...Currents of High Tc Superconductors" - A.M. Campbell and M.F. Ashby The initial work on levitation forces and separation of superconducting powders has

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.

Nonequilibrium states of high tc YBCO superconductors under tunnel injection of quasiparticles

International Nuclear Information System (INIS)

Iguchi, I.; Wang, Q.; Lee, K.; Yoshida, K.

1995-01-01

The nonequilibrium states of high Tc superconductors are investigated by means of tunnel injection of quasiparticles using Pb(or Au)/MgO/YBCO tunnel junctions. The effective critical-current reduction due to tunnel injection is observed, whose behaviour is different from simple heating. The observed results suggest that the resultant nonequilibrium states may also differ from those described by conventional nonequilibrium models

Singularity in the positive Hall coeffcient near pre-onset temperatures in high-Tc superconductors

Science.gov (United States)

Vezzoli, G. C.; Chen, M. F.; Craver, F.; Moon, B. M.; Safari, A.; Burke, T.; Stanley, W.

1990-10-01

Hall measurements using continuous extremely slow cooling and reheating rates as well as employing eqiulibrium point-by-point conventional techniques reveals a clear anomally in RH at pre-onset temperatures near Tc in polycrystalline samples Y1Ba2Cu3O7 and Bi2Sr2Ca2Cu3O10. The anomaly has the appearance of a singularity of Dirac-delta function which parallels earlier work on La1-xSrxCuO4. Recent single crystal work on the Bi-containing high-Tc superconductor is in accord with a clearcut anomaly. The singularity is tentatively interpreted to be associated (upon cooling) with initially the removal of positive holes from the hopping conduction system of the normal state such as from the increased concentration of bound virtual excitons due to increased exciton and hole lifetimes at low temperature. Subsequently the formation of Cooper pairs by mediation from these centers (bound-holes) and/or bound excitons) may cause an ionization of these bound virtual excitons thereby re-introducing holes and electrons into the conduction system at Tc.

Synthesis, Characterization, and Initial Biological Evaluation of [99m Tc]Tc-Tricarbonyl-labeled DPA-α-MSH Peptide Derivatives for Potential Melanoma Imaging.

Science.gov (United States)

Gao, Feng; Sihver, Wiebke; Bergmann, Ralf; Belter, Birgit; Bolzati, Cristina; Salvarese, Nicola; Steinbach, Jörg; Pietzsch, Jens; Pietzsch, Hans-Jürgen

2018-06-06

α-Melanocyte stimulating hormone (α-MSH) derivatives target the melanocortin-1 receptor (MC1R) specifically and selectively. In this study, the α-MSH-derived peptide NAP-NS1 (Nle-Asp-His-d-Phe-Arg-Trp-Gly-NH 2 ) with and without linkers was conjugated with 5-(bis(pyridin-2-ylmethyl)amino)pentanoic acid (DPA-COOH) and labeled with [ 99m Tc]Tc-tricarbonyl by two methods. With the one-pot method the labeling was faster than with the two-pot method, while obtaining similarly high yields. Negligible trans-chelation and high stability in physiological solutions was determined for the [ 99m Tc]Tc-tricarbonyl-peptide conjugates. Coupling an ethylene glycol (EG)-based linker increased the hydrophilicity. The peptide derivatives displayed high binding affinity in murine B16F10 melanoma cells as well as in human MeWo and TXM13 melanoma cell homogenates. Preliminary in vivo studies with one of the [ 99m Tc]Tc-tricarbonyl-peptide conjugates showed good stability in blood and both renal and hepatobiliary excretion. Biodistribution was performed on healthy rats to gain initial insight into the potential relevance of the 99m Tc-labeled peptides for in vivo imaging. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Immobilization of {sup 99}Tc (Re) using Iron-Phosphate Glasses

Energy Technology Data Exchange (ETDEWEB)

Heo, Jong; Xu, Kai; Um, Woo Yong; Hrma, Pavel [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of)

2012-05-15

Technetium-99 ({sup 99}Tc) is a fission product artificially generated during the irradiation of {sup 235}U for commercial power production or {sup 239}Pu for nuclear weapons. Under oxidizing conditions, the dominant species of Tc, the pertechnetate anion (TcO{sub 4} {sup -}), is highly soluble in ground water and thus easily transports through the geologic systems. In addition, because of its high fission yield ({approx}6 %) and long half-life (2.1x10{sup 5} yr), immobilization of {sup 99}Tc has been investigated for decades. Several waste forms such as metallic alloys, sintered titanate ceramics and chemically bonded phosphate ceramics have been proposed to encapsulate {sup 99}Tc. They have not yet been realized in the industrial-scale, mostly either due to the high volatilization of {sup 99}Tc during high temperature process (>1300 .deg. C), or the low {sup 99}Tc loading. Iron-phosphate (FeP) glasses have been developed as alternative waste forms because of their chemical durability equivalent to borosilicate glasses. Additionally, vitrification of radioactive waste by FeP glasses can be done at a relatively low temperature ({approx}1000 .deg. C) and the low-temperature process can reduce the volatilization of {sup 99}Tc significantly. Thus, this work reports the immobilization of {sup 99}Tc by FeP glasses using rhenium (Re) as a surrogate. We also examine the chemical durability of Re-containing FeP glasses using product consistency test (PCT). Experimental results reveal that FeP glass can become a promising candidate for immobilizing {sup 99}Tc

The gradient crystalline structure and microhardness in the treated layer of TC17 via high energy shot peening

International Nuclear Information System (INIS)

Li, Huimin; Liu, Yingang; Li, Miaoquan; Liu, Hongjie

2015-01-01

Graphical abstract: - Highlights: • The gradient nanocrystalline structure was induced in treated layer of TC17. • The thickness of nanograin layer with an average grain size of 10.5 nm was 20 μm. • The composition of the treated layer of TC17 was discussed. • The gradient variation of the microhardness was obtained in treated layer of TC17. - Abstract: The gradient nanocrystalline structure from the topmost surface to the matrix of a bulk coarse-grained TC17 was attained by using high energy shot peening treatment at an air pressure of 0.35 MPa and a processing duration of 30 min. The thickness from the topmost surface with a grain size of about 10.5 nm to the matrix with a micrometer structure was about 120 μm, and the thickness in the nanocrystalline layer was about 20 μm. The microscopic and nanocrystalline structure characteristic in the treated layer were investigated via X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy. The nanograins layer, the nanometer-thick laminated structure layer, the refined grains layer and the low-strain matrix layer occurred in sequence from the topmost surface to the matrix, and therefore the gradient nanocrystalline structure in the treated layer was produced by using high energy shot peening. TEM investigation confirmed that the dislocation activity with very high stacking fault energy induced by surface severe plastic deformation mainly controlled the grain refinement. The microhardness (HV 0.02 ) from the topmost surface to the matrix gradually increased by 43% from 440 to 629 and the gradient variation of the microhardness with the depths from the topmost surface to the matrix of treated TC17 was obtained.

Double-layer rotor magnetic shield performance analysis in high temperature superconducting synchronous generators under short circuit fault conditions

Science.gov (United States)

Hekmati, Arsalan; Aliahmadi, Mehdi

2016-12-01

High temperature superconducting, HTS, synchronous machines benefit from a rotor magnetic shield in order to protect superconducting coils against asynchronous magnetic fields. This magnetic shield, however, suffers from exerted Lorentz forces generated in light of induced eddy currents during transient conditions, e.g. stator windings short-circuit fault. In addition, to the exerted electromagnetic forces, eddy current losses and the associated effects on the cryogenic system are the other consequences of shielding HTS coils. This study aims at investigating the Rotor Magnetic Shield, RMS, performance in HTS synchronous generators under stator winding short-circuit fault conditions. The induced eddy currents in different circumferential positions of the rotor magnetic shield along with associated Joule heating losses would be studied using 2-D time-stepping Finite Element Analysis, FEA. The investigation of Lorentz forces exerted on the magnetic shield during transient conditions has also been performed in this paper. The obtained results show that double line-to-ground fault is of the most importance among different types of short-circuit faults. It was revealed that when it comes to the design of the rotor magnetic shields, in addition to the eddy current distribution and the associated ohmic losses, two phase-to-ground fault should be taken into account since the produced electromagnetic forces in the time of fault conditions are more severe during double line-to-ground fault.

The stress-strain relationship for multilayers of the high Tc superconducting oxides

International Nuclear Information System (INIS)

Hidaka, H.; Yamamura, H.

1988-01-01

This paper reports the calculation of the stress-strain relationship for multilayers of the high Tc superconducting oxides. The elucidation of this relationship is expected quite helpful for the preparation of high-quality multilayers of these materials. This calculation is possible to do in the same way of Timoshenko's bi-metal treatment. The authors did computation of the residual stress and strain, and the state of stress and strain for these multilayers has been acquired in detail by this calculation

Clinical use of 99mTc mebrofenin

International Nuclear Information System (INIS)

Chen Shaoliang; Zhao Huiyang

1989-01-01

A study of 124 subjects was undertaken to evaluate the image patterns of 99m Tc trimethylbromo iminodiacetic acid ( 99m Tc mebrofenin) in hepatobiliary disorders. It exhibits: (a) high specificity for the hepatobiliary system with low urinary excretion rate; (b) high competition to bilirubin; and (c) clearing more rapidly from the blood and rapid transit through the hepatobiliary system. Therefore 99m Tc mebrofenin result in the best visualization of the biliary system either in nonjaundiced or joundiced patient, and the hepatobiliary system can be clearly visualized even in patients with serum bilirubin level up to 30 mg%. The major drawback of this agent is that the urinary excretion rate increased in case of high serum bilirubin

The new 99mTc myocardial perfusion imaging agents: 99mTc-sestamibi and 99mTc-teboroxime

International Nuclear Information System (INIS)

Berman, D.S.; Kiat, H.; Maddahi, J.

1991-01-01

The two new 99m (99mTc) labeled myocardial perfusion agents, 99mTc-Sestamibi and 99mTc-Teboroxime, are now available for routine clinical application. Both agents allow assessment of ejection fraction by the first-pass technique at rest or during exercise, thus providing additional information not available with thallium-201. 99mTc-Sestamibi has long myocardial residence time, as well as adequate myocardial extraction, providing images of higher count density and superior quality compared with thallium-201. 99mTc-Teboroxime has excellent myocardial uptake characteristics but is cleared very rapidly from the myocardium. Both tracers have shown results similar to those obtained with thallium-201 for detection of coronary artery disease and the assessment of defect reversibility. 99mTc-Sestamibi studies using the rest/stress imaging sequence can be accomplished in approximately 5 hours; studies using dual-isotope imaging (rest thallium-201 and stress 99mTc-Sestamibi injection) can be completed in 1 to 2 hours. Gated stress images can be performed with 99mTc-Sestamibi, providing simultaneous information of myocardial perfusion at stress and resting wall motion or thickening and allowing rapid differentiation of ischemic from infarcted tissue. Because of its slow myocardial clearance and absence of redistribution, 99mTc-Sestamibi allows uncoupling of the time of injection from the time of imaging and thus can be valuable in the evaluation of acute myocardial infarction and outcome of thrombolytic therapy. With 99mTc-Teboroxime, rapid serial studies are feasible. Pharmacologic stress and rest studies with 99mTc-Teboroxime single photon emission computed tomography potentially can be completed in under 30 minutes. 73 references

Theory of high-Tc superconducting cuprates based on experimental evidence

International Nuclear Information System (INIS)

Abrikosov, A. A.

1999-01-01

A model of superconductivity in layered high-temperature superconducting cuprates is proposed, based on the extended saddle point singularities in the electron spectrum, weak screening of the Coulomb interaction and phonon-mediated interaction between electrons plus a small short-range repulsion of Hund's, or spin-fluctuation, origin. This permits to explain the large values of Tc, features of the isotope effect on oxygen and copper, the existence of two types of the order parameter, the peak in the inelastic neutron scattering, the positive curvature of the upper critical field, as function of temperature etc

Hydrogen-induced room-temperature plasticity in TC4 and TC21 alloys

DEFF Research Database (Denmark)

Yuan, Baoguo; Jin, Yongyue; Hong, Chuanshi

2017-01-01

In order to reveal the effect of hydrogen on the room-temperature plasticity of the titanium alloys TC4 and TC21, compression tests have been carried out at room temperature. Results show that an appropriate amount of hydrogen can improve the room-temperature plasticity of both the TC4 and TC21...... alloys. The ultimate compression strain of the TC4 alloy containing a hydrogen concentration of 0.5 wt.% increases by 39% compared to the untreated material. For the TC21 alloy the ultimate compression strain is increased by 33% at a hydrogen concentration of 0.6 wt.%. The main reason for the improvement...... of hydrogen-induced room-temperature plasticity of the TC4 and TC21 alloys is discussed....

Design of piezoelectric transducer layer with electromagnetic shielding and high connection reliability

International Nuclear Information System (INIS)

Qiu, Lei; Yuan, Shenfang; Shi, Xiaoling; Huang, Tianxiang

2012-01-01

Piezoelectric transducer (PZT) and Lamb wave based structural health monitoring (SHM) method have been widely studied for on-line SHM of high-performance structures. To monitor large-scale structures, a dense PZTs array is required. In order to improve the placement efficiency and reduce the wire burden of the PZTs array, the concept of the piezoelectric transducers layer (PSL) was proposed. The PSL consists of PZTs, a flexible interlayer with printed wires and signal input/output interface. For on-line SHM on real aircraft structures, there are two main issues on electromagnetic interference and connection reliability of the PSL. To address the issues, an electromagnetic shielding design method of the PSL to reduce spatial electromagnetic noise and crosstalk is proposed and a combined welding–cementation process based connection reliability design method is proposed to enhance the connection reliability between the PZTs and the flexible interlayer. Two experiments on electromagnetic interference suppression are performed to validate the shielding design of the PSL. The experimental results show that the amplitudes of the spatial electromagnetic noise and crosstalk output from the shielded PSL developed by this paper are − 15 dB and − 25 dB lower than those of the ordinary PSL, respectively. Other two experiments on temperature durability ( − 55 °C–80 °C ) and strength durability (160–1600με, one million load cycles) are applied to the PSL to validate the connection reliability. The low repeatability errors (less than 3% and less than 5%, respectively) indicate that the developed PSL is of high connection reliability and long fatigue life. (paper)

About the Scythian Shields

Directory of Open Access Journals (Sweden)

About the Scythian Shields

2017-10-01

Full Text Available Shields played major role in the armament system of the Scythians. Made from organic materials, they are poorly traced on the materials of archaeological excavations. Besides, scaly surface of shields was often perceived in practice as the remnants of the scaly armor. E. V. Chernenko was able to discern the difference between shields’ scaly plates and armor scales. The top edge of the scales was bent inwards, and shield plates had a wire fixation. These observations let significantly increase the number of shields, found in the burial complexes of the Scythians. The comparison of archaeological materials and the images of Scythian warriors allow distinguishing the main forms of Scythian shields. All shields are divided into fencing shields and cover shields. The fencing shields include round wooden shields, reinforced with bronze sheet, and round moon-shaped shields with a notch at the top, with a metal scaly surface. They came to the Scythians under the Greek influence and are known in the monuments of the 4th century BC. Oval shields with scaly surface (back cover shields were used by the Scythian cavalry. They protected the rider in case of frontal attack, and moved back in case of maneuver or closein fighting. Scythian battle tactics were based on rapid approaching the enemy and throwing spears and further rapid withdrawal. Spears stuck in the shields of enemies, forcing them to drop the shields, uncover, and in this stage of the battle the archers attacked the disorganized ranks of the enemy. That was followed by the stage of close fight. Oval form of a wooden shield with leather covering was used by the Scythian infantry and spearmen. Rectangular shields, including wooden shields and the shields pleached from rods, represented a special category. The top of such shield was made of wood, and a pleached pad on leather basis was attached to it. This shield could be a reliable protection from arrows, but it could not protect against javelins

Technology development for radiation shielding analysis

International Nuclear Information System (INIS)

Ha, Jung Woo; Lee, Jae Kee; Kim, Jong Kyung

1986-12-01

Radiation shielding analysis in nuclear engineering fields is an important technology which is needed for the calculation of reactor shielding as well as radiation related safety problems in nuclear facilities. Moreover, the design technology required in high level radioactive waste management and disposal facilities is faced on serious problems with rapidly glowing nuclear industry development, and more advanced technology has to be developed for tomorrow. The main purpose of this study is therefore to build up the self supporting ability of technology development for the radiation shielding analysis in order to achieve successive development of nuclear industry. It is concluded that basic shielding calculations are possible to handle and analyze by using our current technology, but more advanced technology is still needed and has to be learned for the degree of accuracy in two-dimensional shielding calculation. (Author)

Development of a highly sensitive current and position monitor with HTS squids and an HTS magnetic shield

International Nuclear Information System (INIS)

Watanabe, T.; Ikeda, T.; Kase, M.; Yano, Y.; Watanabe, S.; Sasaki, Y.; Kawaguchi, T.

2005-01-01

A highly sensitive current and position monitor with HTS (High-Temperature Superconducting) SQUIDs (Superconducting QUantum Interference Device) and an HTS magnetic shield for the measurement of the intensity of faint beams, such as a radioisotope beam, has been developed for the RIKEN RI beam factory project. The HTS magnetic shield and the HTS current sensor including the HTS SQUID are cooled by a low-vibration pulse-tube refrigerator. Both the HTS magnetic shield and the HTS current sensor were fabricated by dip-coating a thin Bi 2 -Sr 2 -Ca 2 -Cu 3 -O x (Bi-2223) layer on 99.9% MgO ceramic substrates. The HTS technology enables us to develop a system equipped with a downsized and highly sensitive current monitor. Recently, a prototype system was completed and installed in the beam transport line of the RIKEN Ring Cyclotron to measure the DC-current of high-energy heavy-ion beams. As a result, we succeeded in measuring the intensity of the 600 nA 40 Ar 17+ beam (95 MeV/u). We describe the present status of the monitor system and the results of the beam measurements. (author)

Assessment of shielding integrity of Co-60 gamma irradiation-ray scanner at Aflao Border, Ghana

International Nuclear Information System (INIS)

Agbemafo, Edwin Capacity

2016-07-01

This study examines the current state of the shielding integrity of the 38.7 TBq Co-60 gamma ray scanner with an average energy of 1.25 MeV operated by NICK TC Scan Limited, which has been in use for destination inspection at Aflao Border of Ghana, for the past six years, (2010-2016). The facility uses a high energy ionizing radiation in its operation; therefore continuous adequacy of the installed biological shielding is critical to the protection and safety of the workers and the general public. The workload of the facility has increased since its commissioning, requiring the review of the status of the installed shielding. Theoretical calculations for dose rates and barrier thicknesses based on tenth – value layer (TVL) concept and NCRP 151, 2005 recommendations, were done around the scanning facility using the current operational data. The results were then compared with the measured dose rates and the shielding thickness constituted during the commissioning stage, and international standards. Calculated dose rate at commissioning state ranges from 0.6μSv/hr to 2.4μSv/hr with an average dose rate of 1.43μSv/hr and that of the current operational state ranges from 1.1μSv/hr to 2.6μSv/hr with an average dose rate of 1.54μSv/hr, indicating an increase of 7.9%. Even though the dose rates were all below the recommended dose limit of 20μSvh"-"1 by NCRP, there has been an increase in dose to the staff and the general public. It has been observed that, the workload has increased three-fold from the commissioning stage to current operational state over the past six years. The assessment done on the installed shielding using the current operational data indicates that the shielding is inadequate in providing protection for the general public and the workers against X-ray radiation source of energy of at least 6MeV, and therefore the facility in its current state cannot be used to house a linear accelerator of energy up to 10MeV. (au)

Developmental testing of partially volatile neutron shields for high-performance shipping casks

International Nuclear Information System (INIS)

Pope, R.B.; Allen, G.C.; Rack, H.J.; Joseph, B.J.; Dupree, S.A.

1980-01-01

Results of the phase one tests have demonstrated that the neutron-shielding concept described in this paper is a viable design option for spent fuel shipping casks. The tests have shown that the Boro-silicone 236 shield is superior to the other shield materials considered. Repeated TGA, aging and fire tests demonstrated the reliability of the data. A second phase of the test program is now being pursued where the Boro-silicone 236 is injected into all-steel slab sections, and cured in place. 5 tables

High-Tc superconducting microbolometer for terahertz applications

Science.gov (United States)

Ulysse, C.; Gaugue, A.; Adam, A.; Kreisler, A. J.; Villégier, J.-C.; Thomassin, J.-L.

2002-05-01

Superconducting hot electron bolometer mixers are now a competitive alternative to Schottky diode mixers in the terahertz frequency range because of their ultra wideband (from millimeter waves to visible light), high conversion gain, and low intrinsic noise level. High Tc superconductor materials can be used to make hot electron bolometers and present some advantage in term of operating temperature and cooling. In this paper, we present first a model for the study of superconducting hot electron bolometers responsivity in direct detection mode, in order to establish a firm basis for the design of future THz mixers. Secondly, an original process to realize YBaCuO hot electron bolometer mixers will be described. Submicron YBaCuO superconducting structures are expitaxially sputter deposited on MgO substrates and patterned by using electron beam lithography in combination with optical lithography. Metal masks achieved by electron beam lithography are insuring a good bridge definition and protection during ion etching. Finally, detection experiments are being performed with a laser at 850 nm wavelength, in homodyne mode in order to prove the feasibility and potential performances of these devices.

Shielding Design and Radiation Shielding Evaluation for LSDS System Facility

International Nuclear Information System (INIS)

Kim, Younggook; Kim, Jeongdong; Lee, Yongdeok

2015-01-01

As the system characteristics, the target in the spectrometer emits approximately 1012 neutrons/s. To efficiently shield the neutron, the shielding door designs are proposed for the LSDS system through a comparison of the direct shield and maze designs. Hence, to guarantee the radiation safety for the facility, the door design is a compulsory course of the development of the LSDS system. To improve the shielding rates, 250x250 covering structure was added as a subsidiary around the spectrometer. In this study, the evaluations of the suggested shielding designs were conducted using MCNP code. The suggested door design and covering structures can shield the neutron efficiently, thus all evaluations of all conditions are satisfied within the public dose limits. From the Monte Carlo code simulation, Resin(Indoor type) and Tungsten(Outdoor type) were selected as the shielding door materials. From a comparative evaluation of the door thickness, In and Out door thickness was selected 50 cm

Design and setup of a portable stirring device for transfer and dissolution of {sup 99}Mo applied to the use of a {sup 99m}Tc generator; Diseno e implementacion de un modulo portatil para el traslado y disolucion de Mo-99 aplicado al empleo de un generador de Tc-99m

Energy Technology Data Exchange (ETDEWEB)

Lopez, Yon [Universidad Nacional de Ingenieria, Lima (Peru). Facultad de Ingenieria Mecanica; Urquizo, Rafael [Universidad Tecnologica del Peru, Lima (Peru). Facultad de Ingenieria de Sistemas y Electronica; Mendoza, Pablo [Direccion de Investigacion y Desarrollo, Instituto Peruano de Energia Nuclear, Lima (Peru); Rojas, Jorge [Universidad Nacional Mayor San Marcos, Lima (Peru). Facultad de Quimica e Ingenieria Quimica

2014-07-01

This work shows the design and implementation of a portable magnetic stirring device for transfer and efficient dissolution of Mo{sub O}3 coupled to a {sup 99m}Tc generator prototype. The development of this equipment will enable an efficient and safe transfer of {sup 99}Mo at a 2 Ci of maximum activity from the nuclear reactor Huarangal to the point of operation of the {sup 99m}Tc generator equipment. This article describes the mechanical design, volume and shielding calculation, the electronics design and the programmable speed control of the stirring system for radioactive samples. (authors).

Mismatched uptake of Tc-99m-ECD and Tc-99m-HMPAO in subacute cerebral infarction: Tc-99m-ECD for viability and Tc-99m-HMPAO for flow restoration

Energy Technology Data Exchange (ETDEWEB)

Lee, D. S.; Hyun, I. Y.; Kim, S. K. [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)] [and others

1997-07-01

Tc-99m-HMPAO reflects tissue perfusion but Tc-99m-ECD uptake is affected by tissue viability in addition to tissue perfusion which the varied state of cellular retention of Tc-99m-ECD reflects. Luxuriously perfused area on Tc-99m-HMPAO SPECT implies that this cortex was already reperfused either spontaneously or after thrombolysis and that accompanied paralysis of vascular reactivity in those zones warms progressive deterioration. We tried to find out if we can use sequential Tc-99m-ECD/Tc-99m-HMPAO SPECT to reveal cortical perfusion and severity and range of risky areas of cerbral cortex despite reperfusion in sub-acute infarction. In 13 patients (M ; F =7 : 6, mean age 57 (range: 26-84)) with cortical (n=12) and basal ganglia infarction (1), we performed sequential Tc-99m-ECD/Tc-99m-HMPAO SPECT at the same position. At first, 555 MBq of Tc-99m-ECD was injected and imaged and then 1110 MBq of Tc-99m-HMPAO was injected again and imaged with the patients in situ, and the first image (Tc-99m-ECD) and the subtracted image (2nd- 1st : Tc-99m-HMPAO) were compared slice by slice. Study was done from 3 days to 31 days (16{+-}9) after ictus. Tc-99m-ECD uptake was always less than or equal to Tc-99m-HMPAO uptake at the lesion in all cases. Luxury perfusion was prominent in four patients. Mismatched uptake was found in 10 patients. Severity of mismatch showed diverse spectrum and was ranged from total middle cerebral artery territory (1 case) to peripheral thin zones around infarction (2 cases). The other 7 showed intermediate amount of tissues with mismatch , i.e., Tc-99m-ECD defects where Tc-99m-HMPAO uptake is in part increased, normal or decreased. Upon discharge, patients having more uptake with Tc-99m-ECD predicted improvement. Patients having mismatched uptake went dichotomous way. In conclusion, Tc-99m-ECD/Tc-99m-HMPAO sequential SPECT is feasible and reveal both tissue perfusion (Tc-99m-HMPAO ) and discrepant Tc-99m-ECD uptake probably reflecting viability in acute

New applications and developments in the neutron shielding

Directory of Open Access Journals (Sweden)

Uğur Fatma Aysun

2017-01-01

Full Text Available 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.

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.

Evaluation of eye shields made of tungsten and aluminum in high-energy electron beams

International Nuclear Information System (INIS)

Weaver, Randi D.; Gerbi, Bruce J.; Dusenbery, Kathryn E.

1998-01-01

Purpose: To protect the lens and cornea of the eye when treating the eyelid with electrons, we designed a tungsten and aluminum eye shield that protected both the lens and cornea, and also limited the amount of backscatter to the overlying eyelid when using electron beam therapy. Methods and Materials: Custom curved tungsten eye shields, 2 mm and 3 mm thick, were placed on Kodak XV film on 8 cm polystyrene and irradiated to evaluate the transmission through the shields. To simulate the thickness of the eyelid and to hold the micro-TLDs, an aquaplast mold was made to match the curvature of the eye shields. Backscatter was measured by placing the micro-TLDs on the beam entrance side to check the dose to the underside of the eyelid. Measurements were done with no aluminum, 0.5, and 1.0 mm of aluminum on top of the tungsten eye shields. The measurements were repeated with 2- and 3-mm flat pieces of lead to determine both the transmission and the backscatter dose for this material. Results: Tungsten proved to be superior to lead for shielding the underlying structures and for reducing backscatter. At 6 MeV, a 3-mm flat slab of tungsten plus 0.5 mm of aluminum, resulted in .042 Gy under the shield when 1.00 Gy is delivered to d max . At 6 MeV for a 3-mm lead plus 0.5-mm aluminum, .046 Gy was measured beneath the shield, a 9.5% decrease with the tungsten. Backscatter was also decreased from 1.17 to 1.13 Gy, a 4% decrease, when using tungsten plus 0.5 mm of aluminum vs. the same thickness of lead. Measurements using 9 MeV were performed in the same manner. With 3 mm tungsten and 0.5 mm of aluminum, at 3 mm depth the dose was .048 Gy compared to .079 Gy with lead and aluminum (39% decrease). Additionally, the backscatter dose was 3% less using tungsten. Simulating the lens dose 3 mm beyond the shield for the 2-mm and 3-mm custom curved tungsten eye shields plus 0.5 mm of aluminum was .030 and .024 Gy, respectively, using 6 MeV (20% decrease). Using 9-MeV electrons, the dose

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

International Nuclear Information System (INIS)

Chu, Sung Sil; Suh, Chang Ok; Kim, Gwi Eon

2002-01-01

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

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

Modifying zirconia solid electrolyte surface property to enhance oxide transport

Energy Technology Data Exchange (ETDEWEB)

Liaw, B.Y.; Song, S.Y. [Univ. of Hawaii, Honolulu, HI (United States)

1996-12-31

Bismuth-strontium-calcium-copper oxide (Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}, BSCCO) is known for its high T{sub c} superconducting behavior and mixed conducting property. The applicability of similar high T{sub c} cuprates for intermediate-temperature solid oxide fuel cell (SOFC) application has been studied recently. We investigated the electrochemical behavior of several Ag{vert_bar}BSCCO{vert_bar}10 mol% yttria-stabilized zirconia (YSZ){vert_bar}Ag and Ag{vert_bar}YSZ{vert_bar}Ag cells using complex impedance spectroscopy. A highly uniform and porous microstructure was observed at the interface of the YSZ and BSCCO. The ionic conductivity determined from the Nyquest plots in the temperature range of 200-700{degrees}C agrees with the values reported in the literature. The specific resistance of the BSCCO{vert_bar}YSZ interface was also determined to be lower than those of the conventional manganite electrode, suggesting that BSCCO seems attractive for cathode applications in SOFC.

High-Tc superconducting antenna-coupled microbolometer on silicon

Science.gov (United States)

Rice, Joseph P.; Grossman, Erich N.; Borcherdt, L. J.; Rudman, D. A.

1994-05-01

A process is described for fabricating antenna-coupled resistive-edge microbolometers based on the high-Tc superconductor YBa2Cu3O7 (YBCO) on silicon. The YBCO and a buffer layer of yttria-stabilized zirconia (YSZ) were grown epitaxially on silicon to minimize excess electrical noise. A silicon-micromachined YBCO/YSZ air-bridge was incorporated to minimize the thermal conductance and the heat capacity. The thermal conductance of the air-bridge was measured to be 3 X 10-6 W/K at a temperature of 100 K. At an operating temperature of 89 K, the detector is estimated to have a response time of 2 microsecond(s) , a responsivity of the 1000 V/W range, and a noise-equivalent power in the 10-12 W/Hz1/2 range at 1000 Hz.

Shielding benchmark problems

International Nuclear Information System (INIS)

Tanaka, Shun-ichi; Sasamoto, Nobuo; Oka, Yoshiaki; Kawai, Masayoshi; Nakazawa, Masaharu.

1978-09-01

Shielding benchmark problems were prepared by the Working Group of Assessment of Shielding Experiments in the Research Comittee on Shielding Design of the Atomic Energy Society of Japan, and compiled by the Shielding Laboratory of Japan Atomic Energy Research Institute. Twenty-one kinds of shielding benchmark problems are presented for evaluating the calculational algorithm and the accuracy of computer codes based on the discrete ordinates method and the Monte Carlo method and for evaluating the nuclear data used in the codes. (author)

Accumulation of Tc-99m-MIBI and Tc-99m-tetrofosmin in tumor cells. Uptake and washout studies

International Nuclear Information System (INIS)

Rodrigues, M.; Aghajanian, A.A.; Sinzinger, H.; Kalinowska, W.; Zielinski, C.

2002-01-01

Tc-99m-tetrofosmin seem to be promising for the in-vivo imaging and characterization of tumors with high cellular metabolic activity, such as cells rich in mitochondria or enhanced mitochondrial activity

ICRF Faraday shield plasma sheath models: Low and high conductivity limits

International Nuclear Information System (INIS)

Whealton, J.H.; Ryan, P.M.; Raridon, R.J.

1989-01-01

Using a 2-D nonlinear formulation which explicitly considers the plasma edge near a Faraday shield in a self consistent manner, progress is indicated in the modeling of the ion motion for a Faraday shield concept and model suggested by Perkins. Several models are considered which may provide significant insight into the impurities generation for ICRH antennas. 6 refs., 8 figs

A perturbation technique for shield weight minimization

International Nuclear Information System (INIS)

Watkins, E.F.; Greenspan, E.

1993-01-01

The radiation shield optimization code SWAN (Ref. 1) was originally developed for minimizing the thickness of a shield that will meet a given dose (or another) constraint or for extremizing a performance parameter of interest (e.g., maximizing energy multiplication or minimizing dose) while maintaining the shield volume constraint. The SWAN optimization process proved to be highly effective (e.g., see Refs. 2, 3, and 4). The purpose of this work is to investigate the applicability of the SWAN methodology to problems in which the weight rather than the volume is the relevant shield characteristic. Such problems are encountered in shield design for space nuclear power systems. The investigation is carried out using SWAN with the coupled neutron-photon cross-section library FLUNG (Ref. 5)

High Tc superconducting energy storage systems

Energy Technology Data Exchange (ETDEWEB)

Werfel, Frank [Adelwitz Technologiezentrum GmbH (ATZ), Arzberg-Adelwitz (Germany)

2012-07-01

Electric energy is basic to heat and light our homes, to power our businesses and to transport people and goods. Powerful storage techniques like SMES, Flywheel, Super Capacitor, and Redox - Flow batteries are needed to increase the overall efficiency, stability and quality of electrical grids. High-Tc superconductors (HTS) possess superior physical and technical properties and can contribute in reducing the dissipation and losses in electric machines as motors and generators, in electric grids and transportation. The renewable energy sources as solar, wind energy and biomass will require energy storage systems even more as a key technology. We survey the physics and the technology status of superconducting flywheel energy storage (FESS) and magnetic energy storage systems (SMES) for their potential of large-scale commercialization. We report about a 10 kWh / 250 kW flywheel with magnetic stabilization of the rotor. The progress of HTS conductor science and technological engineering are basic for larger SMES developments. The performance of superconducting storage systems is reviewed and compared. We conclude that a broad range of intensive research and development in energy storage is urgently needed to produce technological options that can allow both climate stabilization and economic development.

Study of technetium behaviour in radiopharmaceuticals. Characterization of sup(99m)Tc-pyrophosphate, sup(99m)Tc-dimercaptosuccinate, sup(99m)Tc-diethylenetriaminepentaacetate complexes and sup(99m)Tc-colloidal rhenium sulphide

International Nuclear Information System (INIS)

Saccavini, J.-C.

1980-12-01

The chemistry of technetium in extremely dilute solution was approached through the study of three complexing agents and a colloid. By the application of high-performance chromatographic techniques to the analysis of (Tc-pyro), (Tc-DTPA), (Tc-DMSA) complexes it was possible to isolate one or more chelates from a single complexing agent. Addition of pertechnetates to a solution of sodium pyrophosphates and stannous chloride at neutral pH leads to the formation of two complexes, both highly osteotropic. By the use of sup(117m)Sn it was shown that tin employed as reducing agent enters into the composition of one of the two complexes, either of which may be obtained preferentially by varying the (Sn)/(pyro) ratio. With technetium at acid pH (2.5) DMSA gives one or more chelates according to the concentration of the reagents present. DTPA with technetium at neutral pH gives a single complex for which a structure is proposed. The addition of calcium, indispensable for DTPA injection, leads to the appearance of a second bimetallic complex in very much smaller proportions than the first. The size distribution of some colloids was studied by ultrafiltration and permeation on gel. The preparation of colloidal rhenium sulphide and the technetium labelling conditions needed to obtain a very fine colloid were developed. The behaviour of technetium in the presence of colloidal rhenium sulphide and tin pyrophosphate was followed by sup(99m)Tc - sup(186)Re and sup(99m)Tc - sup(117m)Sn double-labelling tests. One reduced technetium fraction associates with the hydrolysed tin, the other follows the rhenium sulphide [fr

Determination of radiochemical purity and pharmacokinetic parameters of sup(99m)Tc-sulphur colloid and sup(99m)Tc-tin colloid

International Nuclear Information System (INIS)

Jovanovic, V.; Konstantinovska, D.; Milivojevic, K.; Bzenic, J.

1981-01-01

Labelling yield and radiochemical purity, higher than 95%, of sup(99m)Tc-colloid preparations were determined by using the paper chromatography method. Less than 3% of labelled citric acid, added to the preparation as a buffer solution, has been found in sup(99m)Tc-sulphur colloid. High radiochemical purity and optimum size of colloid particles has also been proved by biodistribution studies on experimental animals. The analysis performed has shown that more than 50% of sup(99m)Tc-colloid preparations excreted by urine is sup(99m)TcO - , the remaining past 50% being protein bound sup(99m)Tc. Biological half-time of excretion of the fast phase is the same for both preparations, i.e. 10 min, while for the slow component it is 120 min in sup(99m)Tc-S-colloid and 160 min in sup(99m)Tc-Sn colloid. (orig.) [de

CD3+CD8+CD161high Tc17 cells are depleted in HIV-infection

DEFF Research Database (Denmark)

Gaardbo, Julie Christine; Hartling, Hans Jakob; Thorsteinsson, Kristina

2012-01-01

CD8+ Tc17 cells with pro-inflammatory properties have only recently been acknowledged, and Tc17 cells in HIV-infection are undescribed. CD3+CD8+CD161 Tc17 cells and the production of Interleukin-17 were examined in untreated and treated HIV-infected patients, HIV-HCV co-infected patients...... and healthy controls. Depletion of CD3+CD8+CD161 Tc17 cells and diminished production of Interleukin-17 in HIV-infected patients was found. The level of Tc17 cells was associated with the level of the CD4+ count in treated patients....

Electromagnetic shielding formulae

International Nuclear Information System (INIS)

Dahlberg, E.

1979-02-01

This addendum to an earlier collection of electromagnetic shielding formulae (TRITA-EPP-75-27) contains simple transfer matrices suitable for calculating the quasistatic shielding efficiency for multiple transverse-field and axial-field cylindrical and spherical shields, as well as for estimating leakage fields from long coaxial cables and the normal-incidence transmission of a plane wave through a multiple plane shield. The differences and similarities between these cases are illustrated by means of equivalent circuits and transmission line analogies. The addendum also includes a discussion of a possible heuristic improvement of some shielding formulae. (author)

Performance of TcI/TcVI/TcII Chagas-Flow ATE-IgG2a for universal and genotype-specific serodiagnosis of Trypanosoma cruzi infection.

Directory of Open Access Journals (Sweden)

Glaucia Diniz Alessio

2017-03-01

Full Text Available Distinct Trypanosoma cruzi genotypes have been considered relevant for patient management and therapeutic response of Chagas disease. However, typing strategies for genotype-specific serodiagnosis of Chagas disease are still unavailable and requires standardization for practical application. In this study, an innovative TcI/TcVI/TcII Chagas Flow ATE-IgG2a technique was developed with applicability for universal and genotype-specific diagnosis of T. cruzi infection. For this purpose, the reactivity of serum samples (percentage of positive fluorescent parasites-PPFP obtained from mice chronically infected with TcI/Colombiana, TcVI/CL or TcII/Y strain as well as non-infected controls were determined using amastigote-AMA, trypomastigote-TRYPO and epimastigote-EPI in parallel batches of TcI, TcVI and TcII target antigens. Data demonstrated that "α-TcII-TRYPO/1:500, cut-off/PPFP = 20%" presented an excellent performance for universal diagnosis of T. cruzi infection (AUC = 1.0, Se and Sp = 100%. The combined set of attributes "α-TcI-TRYPO/1:4,000, cut-off/PPFP = 50%", "α-TcII-AMA/1:1,000, cut-off/PPFP = 40%" and "α-TcVI-EPI/1:1,000, cut-off/PPFP = 45%" showed good performance to segregate infections with TcI/Colombiana, TcVI/CL or TcII/Y strain. Overall, hosts infected with TcI/Colombiana and TcII/Y strains displayed opposite patterns of reactivity with "α-TcI TRYPO" and "α-TcII AMA". Hosts infected with TcVI/CL strain showed a typical interweaved distribution pattern. The method presented a good performance for genotype-specific diagnosis, with global accuracy of 69% when the population/prototype scenario include TcI, TcVI and TcII infections and 94% when comprise only TcI and TcII infections. This study also proposes a receiver operating reactivity panel, providing a feasible tool to classify serum samples from hosts infected with distinct T. cruzi genotypes, supporting the potential of this method for universal and genotype-specific diagnosis

High Tc superconducting three-terminal device under quasi-particle injection

International Nuclear Information System (INIS)

Hashimoto, K.; Kabasawa, U.; Tonouchi, M.; Kobayashi, T.

1988-01-01

A new type of the current injection type three terminal device was fabricated using the high Tc YBaCuO thin epitaxial films, wherein the hot quasi-particle injection effect on the superconducting current was closely examined. The zero bias drain current was efficiently suppressed by the injection of the hot quasi-particles through the gate electrode. Though it is speculative, a comparison of the experimental results and analyses based on the familiar BCS theory intimates that the main mechanism of the current modulation is the non-equilibrium superconductivity due to accumulation of the excess quasi-particles

Observation of an hexatic vortex glass in flux lattices of the high Tc superconductor Bi2.1Sr1.9Ca0.9Cu2O8+δ

International Nuclear Information System (INIS)

Bishop, D.J.; Gammel, P.L.; Murray, C.A.; Mitzi, D.B.; Kapitulnik, A.

1990-01-01

We report observation of hexatic order in Abrikosov flux lattices in very clean crystals of the high T c superconductor Bi 2.1 Sr 1.9 Ca 0.9 Cu 2 O 8+δ (BSCCO). Our experiments consist of in situ magnetic decoration of the flux lattice at 4.2 K. Analysis of the decoration images shows that the positional order decays exponentially with a correlation length of a few lattice constants while the orientational order persists for hundreds of lattice constants and decays algebraically with an exponent η 6 =0.06±0.01. Our results confirm recent theoretical speculation that the positional order should be far more sensitive to disorder than the orientational order and that the low temperature ordered phase of the flux lines in these systems might be an hexatic glass

Development of HANARO ST3 shield

International Nuclear Information System (INIS)

Park, K. N.; Lee, J. S.; Shim, H. S.

2004-12-01

This report contains the design, fabrication and accurate installation of ST3 shield, which would be installed at ST3 beam port of HANARO. At first, we designed and fabricated ST3 shield casemate composed of 14 blocks. We filled it with heavy concrete, lead ingot and polyethylene that mixed B 4 C powder and epoxy. The average filling density of total shield casemate was 4.7g/cm 3 . The developed ST3 shield was installed at the ST3 beam port and the accuracy of installation for each beam path and channel was evaluated. We found that the extraction of neutron beam to meet the requirement of neutron spectrometer is possible. Also, we developed ancillary equipment such as BGU, quick shutter and exterior shield door for the effective opening and closing of neutron beam. As a result of this study, it was found that neutron spectrometer such as neutron reflectometer and high intensity powder diffractomater can be installed at the ST3 beam port

99mTc bone scanning agents preparation and chemical analysis of Tc(Sn)pyrophosphate, Tc(Sn)MDP and Tc(Sn)HMDP

International Nuclear Information System (INIS)

Kroesbergen, J.

1986-01-01

This thesis describes a comparison of the preparation, composition and properties of three bone scanning agents: 99m Tc(Sn)pyrophosphate, 99m Tc(Sn)MDP and 99m Tc(Sn)HMDP. This study has been performed for two reasons: First to investigate the preparation and composition of the radiopharmaceuticals as a function of experimental conditions. Together with previously reported results for 99m Tc(Sn)EHDP, obtained in a similar way, this enables to use well-defined preparations of the bone scanning agents. Secondly to gain an insight in the mechanism in which the agents behave 'in vivo'. Because the 'in vivo' process is too complicated to study directly, it seemed more appropriate to perform 'in vitro' investigations as simplifications of the 'in vivo' situation. 304 refs.; 26 figs.; 31 tabs

Altered [99mTc]Tc-MDP biodistribution from neutron activation sourced 99Mo.

Science.gov (United States)

Demeter, Sandor; Szweda, Roman; Patterson, Judy; Grigoryan, Marine

2018-01-01

Given potential worldwide shortages of fission sourced 99 Mo/ 99m Tc medical isotopes there is increasing interest in alternate production strategies. A neutron activated 99 Mo source was utilized in a single center phase III open label study comparing 99m Tc, as 99m Tc Methylene Diphosphonate ([ 99m Tc]Tc-MDP), obtained from solvent generator separation of neutron activation produced 99 Mo, versus nuclear reactor produced 99 Mo (e.g., fission sourced) in oncology patients for which an [ 99m Tc]Tc-MDP bone scan would normally have been indicated. Despite the investigational [ 99m Tc]Tc-MDP passing all standard, and above standard of care, quality assurance tests, which would normally be sufficient to allow human administration, there was altered biodistribution which could lead to erroneous clinical interpretation. The cause of the altered biodistribution remains unknown and requires further research.

Shielding in ungated field emitter arrays

Energy Technology Data Exchange (ETDEWEB)

Harris, J. R. [U.S. Navy Reserve, Navy Operational Support Center New Orleans, New Orleans, Louisiana 70143 (United States); Jensen, K. L. [Code 6854, Naval Research Laboratory, Washington, D.C. 20375 (United States); Shiffler, D. A. [Directed Energy Directorate, Air Force Research Laboratory, Albuquerque, New Mexico 87117 (United States); Petillo, J. J. [Leidos, Billerica, Massachusetts 01821 (United States)

2015-05-18

Cathodes consisting of arrays of high aspect ratio field emitters are of great interest as sources of electron beams for vacuum electronic devices. The desire for high currents and current densities drives the cathode designer towards a denser array, but for ungated emitters, denser arrays also lead to increased shielding, in which the field enhancement factor β of each emitter is reduced due to the presence of the other emitters in the array. To facilitate the study of these arrays, we have developed a method for modeling high aspect ratio emitters using tapered dipole line charges. This method can be used to investigate proximity effects from similar emitters an arbitrary distance away and is much less computationally demanding than competing simulation approaches. Here, we introduce this method and use it to study shielding as a function of array geometry. Emitters with aspect ratios of 10{sup 2}–10{sup 4} are modeled, and the shielding-induced reduction in β is considered as a function of tip-to-tip spacing for emitter pairs and for large arrays with triangular and square unit cells. Shielding is found to be negligible when the emitter spacing is greater than the emitter height for the two-emitter array, or about 2.5 times the emitter height in the large arrays, in agreement with previously published results. Because the onset of shielding occurs at virtually the same emitter spacing in the square and triangular arrays, the triangular array is preferred for its higher emitter density at a given emitter spacing. The primary contribution to shielding in large arrays is found to come from emitters within a distance of three times the unit cell spacing for both square and triangular arrays.

Pharmacological study of 99mTc-CO-MIBI, a new mycoardial perfusion imaging agent comparison to 99mTc-MIBI

International Nuclear Information System (INIS)

Zhao Jiandong; Wang Jincheng; Mi Hongzhi

2004-01-01

For many years, 99m Tc-MIBI has been widely used for the diagnosis of ischemic heart disease. Although it has been regarded as a successful myocardial imaging agent, it has a notable defect of high liver radioactivities due to high uptake and slowly excrete. Recently, researchers had developed a new intermediate [ 99m Tc(CO) 3 (OH 2 ) 3 ] + , considering 99m Tc-MIBI excellent biodistribution, they synthesized a new class of compound- 99m Tc-CO-MIBI with [ 99m Tc(CO) 3 ] + core and ligand MIBI. Previous studies have preliminary demonstrated the following favorable properties: rapid blood-pool clearance, high myocardial extraction and rapid clearance kinetics from liver that indicated 99m Tc-CO-MIBI a promising new myocardial perfusion imaging agent. Furthermore, researchers separated the compound by changing liquid pH value and prepared single alkaline component 99m Tc-CO-MIBI. The pharmacological experiments in rat have provided better results on its biodistribution in vivo and much faster clearance kinetics from liver compared to 99mTc-MIBI. To evaluate the potential application of 99m Tc-CO-MIBI, further investigations are necessary to determine the evidence for enhanced ability in clinical decision making as a novel new myocardial perfusion imaging agent. Objective: Here, perform pharmacological experiment of 99m Tc-CO-MIBI, a new technetium-99m-labeled myocardial imaging agent compared to 99m Tc-MIBI in canines. To identify whether it is feasible in clinical application as a novel myocardial imaging agent, or not. Results: Accordingly, prepared the single alkaline component of 99m Tc-CO-MIBI. The complex was stable up to at least 7 hours after synthesized in vitro at either room temperature or 37 degree C water bath. Labeling yield and radiochemical purity (RCP) of the complex were evaluated by TLC and HPLC, the labeling percent was 93%-97% and the RCP was over 90%. Then administer 555MBq to every dog each times. A total of 5 dogs were involved. The data of

ORNL shielded facilities capable of remote handling of highly radioactive beta--gamma emitting materials

International Nuclear Information System (INIS)

Whitson, W.R.

1977-09-01

A survey of ORNL facilities having adequate shielding and containment for the remote handling of experimental quantities of highly radioactive beta-gamma emitting materials is summarized. Portions of the detailed descriptions of these facilities previously published in ORNL/TM-1268 are still valid and are repeated

Shielding member for thermonuclear device

Energy Technology Data Exchange (ETDEWEB)

Onozuka, Masanori

1997-06-30

In a thermonuclear device for shielding fast neutrons by shielding members disposed in a shielding vessel (vacuum vessel and structures such as a blanket disposed in the vacuum vessel), the shielding member comprises a large number of shielding wires formed fine and short so as to have elasticity. The shielding wires are sealed in a shielding vessel together with water, and when the width of the shielding vessel is changed, the shielding wires follow after the change of the width while elastically deforming in the shielding vessel, so that great stress and deformation are not formed thereby enabling to improve reliability. In addition, the length, the diameter and the shape of each of the shielding wires can be selected in accordance with the shielding space of the shielding vessel. Even if the shape of the shielding vessel is complicated, the shielding wires can be inserted easily. Accordingly, the filling rate of the shielding members can be changed easily. It can be produced more easily compared with a conventional spherical pebbles. It can be produced more easily than existent spherical shielding pebbles thereby enabling to reduce the production cost. (N.H.)

Criticality safety and shielding design issues in the development of a high-capacity cask for truck transport

International Nuclear Information System (INIS)

Boshoven, J.K.

1992-01-01

General Atomics (GA) will be submitting an application for certification to the US Nuclear Regulatory Commission (NRC) for the GA-4 and GA-9 Casks In 1992. The GA-4 and GA-9 Casks are high-capacity legal weight truck casks designed to transport light water reactor spent fuel assemblies. To maintain a capacity of four pressurized-water-reactor (PWR) spent fuel assemblies, the GA-4 Cask uses burnup credit as part of the criticality control for initial enrichments over 3.0 wt% U-235. Using the US Department of Energy (DOE) Burnup Credit Program as a basis, GA has performed burnup credit analysis which is included in the Safety Analysis Report for Packaging (SARP). The GA-9 Cask can meet the criticality safety requirements using the ''fresh fuel'' assumption. Our approach to shielding design is to optimize the GA-4 and GA-9 Cask shielding configurations for minimum weights and maximum payloads. This optimization involves the use of the most effective shielding material, square cross-section geometry with rounded corners and tapered neutron shielding sections in the non-fuel regions

The Spallation Neutron Source (SNS) conceptual design shielding analysis

International Nuclear Information System (INIS)

Johnson, J.O.; Odano, N.; Lillie, R.A.

1998-03-01

The shielding design is important for the construction of an intense high-energy accelerator facility like the proposed Spallation Neutron Source (SNS) due to its impact on conventional facility design, maintenance operations, and since the cost for the radiation shielding shares a considerable part of the total facility costs. A calculational strategy utilizing coupled high energy Monte Carlo calculations and multi-dimensional discrete ordinates calculations, along with semi-empirical calculations, was implemented to perform the conceptual design shielding assessment of the proposed SNS. Biological shields have been designed and assessed for the proton beam transport system and associated beam dumps, the target station, and the target service cell and general remote maintenance cell. Shielding requirements have been assessed with respect to weight, space, and dose-rate constraints for operating, shutdown, and accident conditions. A discussion of the proposed facility design, conceptual design shielding requirements calculational strategy, source terms, preliminary results and conclusions, and recommendations for additional analyses are presented

99mTc-HYNIC-derivatized ternary ligand complexes for 99mTc-labeled polypeptides with low in vivo protein binding

International Nuclear Information System (INIS)

Ono, Masahiro; Arano, Yasushi; Mukai, Takahiro; Fujioka, Yasushi; Ogawa, Kazuma; Uehara, Tomoya; Saga, Tsuneo; Konishi, Junji; Saji, Hideo

2001-01-01

6-Hydrazinopyridine-3-carboxylic acid (HYNIC) is a representative agent used to prepare technetium-99m ( 99m Tc)-labeled polypeptides with tricine as a coligand. However, 99m Tc-HYNIC-labeled polypeptides show delayed elimination rates of the radioactivity not only from the blood but also from nontarget tissues such as the liver and kidney. In this study, a preformed chelate of tetrafluorophenol (TFP) active ester of [ 99m Tc](HYNIC)(tricine)(benzoylpyridine: BP) ternary complex was synthesized to prepare 99m Tc-labeled polypeptides with higher stability against exchange reactions with proteins in plasma and lysosomes using the Fab fragment of a monoclonal antibody and galactosyl-neoglycoalbumin (NGA) as model polypeptides. When incubated in plasma, [ 99m Tc](HYNIC-Fab)(tricine)(BP) showed significant reduction of the radioactivity in high molecular weight fractions compared with [ 99m Tc](HYNIC-Fab)(tricine) 2. When injected into mice, [ 99m Tc](HYNIC-NGA)(tricine)(BP) was metabolized to [ 99m Tc](HYNIC-lysine)(tricine)(BP) in the liver with no radioactivity detected in protein-bound fractions in contrast to the observations with [ 99m Tc](HYNIC-NGA)(tricine) 2. In addition, [ 99m Tc](HYNIC-NGA)(tricine)(BP) showed significantly faster elimination rates of the radioactivity from the liver as compared with [ 99m Tc](HYNIC-NGA)(tricine) 2. Similar results were observed with 99m Tc-labeled Fab fragments where [ 99m Tc](HYNIC-Fab)(tricine)(BP) exhibited significantly faster elimination rates of the radioactivity not only from the blood but also from the kidney. These findings indicated that conjugation of [ 99m Tc](HYNIC)(tricine)(BP) ternary ligand complex to polypeptides accelerated elimination rates of the radioactivity from the blood and nontarget tissues due to low binding of the [ 99m Tc](HYNIC)(tricine)(BP) complex with proteins in the blood and in the lysosomes. Such characteristics would render the TFP active ester of [ 99m Tc](HYNIC)(tricine)(BP) complex

Enhanced⁹⁹Tc retention in glass waste form using Tc(IV)-incorporated Fe minerals

OpenAIRE

Um, W; Luksic, SA; Wang, G; Saslow, S; Kim, DS; Schweiger, MJ; Soderquist, CZ; Bowden, ME; Lukens, WW; Kruger, AA

2017-01-01

© 2017 Elsevier B.V. Technetium ( 99 Tc) immobilization by doping into iron oxide mineral phases may alleviate the problems with Tc volatility during vitrification of nuclear waste. Because reduced Tc, Tc(IV), substitutes for Fe(III) in the crystal structure by a process of Tc reduction from Tc(VII) to Tc(IV) followed by co-precipitation of Fe oxide minerals, two Tc-incorporated Fe minerals (Tc-goethite and Tc-magnetite/maghemite) were prepared and tested for Tc retention in glass melt sample...

Preparation, quality control and biological characterization of 99mTc-vincristine

International Nuclear Information System (INIS)

Saira Hina; Muhammad Ibrahim Rajoka; Asma Haque

2015-01-01

In present study it is aimed to radiolabel vincristine with 99m Tc and to evaluate bioaffinity of 99m Tc labeled vinc. The optimum conditions required to obtain 99.6 ± 0.4 %, (n = 5) radiolabeling yield of 99m Tc-vincristine ( 99m Tc-vinc) were as follows: pH 4, 5 µg of vincristine sulphate, 6 µg SnCl 2 ·2H 2 O as a reducing agent and 10 min incubation time at room temperature. Quality control of 99m Tc-vinc was done by using paper electrophoresis and thin layer chromatography. The radiolabeling yield was confirmed by High performance liquid chromatography using radioactive and UV detector operating at 230 nm. 99m Tc-vinc was stable in vitro for 5 h. Biodistribution and scintigraphy of 99m Tc-vinc was performed in mice and rabbits respectively and that 99m Tc-vinc showed high uptake of it in liver and spleen. Finally 99m Tc-vinc may be the potential imaging agent for liver and spleen. (author)

Irrigoscopy - irrigography method, dosimetry and radiation shielding

International Nuclear Information System (INIS)

Zubanov, Z.; Kolarevic, G.

1999-01-01

Use of patient's radiation shielding during radiology diagnostic procedures in our country is insufficiently represent, so patients needlessly receive very high entrance skin doses in body areas which are not in direct x-ray beam. During irrigoscopy, patient's radiation shielding is very complex problem, because of the organs position. In the future that problem must be solved. We hope that some of our suggestions about patient's radiation shielding during irrigoscopy, can be a small step in that way. (author)

The Fabrication of Internal Shielding using Provil and Cerrobend

International Nuclear Information System (INIS)

Kim Jong Hwa; Lee, Kang Hyun; Son, Jeong Hye

1996-01-01

The skin cancer is a highly curable disease which frequently occurs in the head and neck region exposed to the sun. When the eyelid is treated usually eye shield made of lead is used to protect the eyeball as a internal shield. For the same reason on internal shield should be used when the nose is treated when electron to protect the nasal mucosa. Our hospital made an internal shield for the treatment of the skin cancer on the nose using provil and cerrobend. The characteristics of the internal shield were examined.

Estimation of temperature distribution in a reactor shield

International Nuclear Information System (INIS)

Agarwal, R.A.; Goverdhan, P.; Gupta, S.K.

1989-01-01

Shielding is provided in a nuclear reactor to absorb the radiations emanating from the core. The energy of these radiations appear in the form of heat. Concrete which is commonly used as a shielding material in nuclear power plants must be able to withstand the temperatures and temperature gradients appearing in the shield due to this heat. High temperatures lead to dehydration of the concrete and in turn reduce the shielding effectiveness of the material. Adequate cooling needs to be provided in these shields in order to limit the maximum temperature. This paper describes a method to estimate steady state and transient temperature distribution in reactor shields. The results due to loss of coolant in the coolant tubes have been studied and presented in the paper. (author). 5 figs

Efficiency of steel-concrete compositions in a side shielding of high-energy proton accelerators

International Nuclear Information System (INIS)

Getmanov, V.B.; Kryuchkov, V.P.; Lebedev, V.N.

1983-01-01

Aiming at the study of efficiency of application of heavy concretes with the density up to 6.3 g/cm -3 with iron-ore aggregate and steel scrap with shot the calculational study on high-energy radiation attenuation in the accelerator side shield has been carried out. The calculation is made for five concretes with the density 2.38; 3.66; 4.68; 5.34; 6.30 g x cm -3 and for pure iron. The real chemical composition of each concrete, including hydrogen, is taken into account. The real spectrum of hadron generated in the materiai of evacuated ionguide wall under the effect of the 70 GeV proton beam incident on the wall at a narrow angle THETA -3 ensuring the same ratio of the dose or hadron fluence with the energy > 20 MeV attenuation is accepted as a relative shield efficiency of the material. It is shown, that for steel-concrete compositions with the density > 5.6 gxcm -3 the relative shield efficiency decreases sharply. It is also shown, that aplication of concretes with the density 3.6-3.7 gxcm -3 is expedient and economically profitable

Infrared detection with high-[Tc] bolometers and response of Nb tunnel junctions to picosecond voltage pulses

Energy Technology Data Exchange (ETDEWEB)

Verghese, S.

1993-05-01

Oxide superconductors with high critical temperature [Tc] make sensitive thermometers for several types of infrared bolometers. The authors built composite bolometers with YBa[sub 2]Cu[sub 3]O[sub 7[minus][delta

Power Systems Development Facility Gasification Test Campaign TC25

Energy Technology Data Exchange (ETDEWEB)

Southern Company Services

2008-12-01

In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of TC25, the second test campaign using a high moisture lignite coal from the Red Hills mine in Mississippi as the feedstock in the modified Transport Gasifier configuration. TC25 was conducted from July 4, 2008, through August 12, 2008. During TC25, the PSDF gasification process operated for 742 hours in air-blown gasification mode. Operation with the Mississippi lignite was significantly improved in TC25 compared to the previous test (TC22) with this fuel due to the addition of a fluid bed coal dryer. The new dryer was installed to dry coals with very high moisture contents for reliable coal feeding. The TC25 test campaign demonstrated steady operation with high carbon conversion and optimized performance of the coal handling and gasifier systems. Operation during TC25 provided the opportunity for further testing of instrumentation enhancements, hot gas filter materials, and advanced syngas cleanup technologies. The PSDF site was also made available for testing of the National Energy Technology Laboratory's fuel cell module and Media Process Technology's hydrogen selective membrane with syngas from the Transport Gasifier.

Development of the Mo loading apparatus for adsorbing high level 99Mo to PZC and packing in 99mTc generator column

International Nuclear Information System (INIS)

Hishinuma, Yukio; Ohmori, Hiroyuki; Noguchi, Tuneyuki; Tatenuma, Katsuyoshi; Genka, Tsuguo; Machi, Sueo

2006-01-01

For developing the automatic system to produce the PZC- 99m Tc generator column based on (n, gamma) method, we developed and fabricated the proto-type apparatus for semi hot test to prepare and pack PZC adsorbed 99 Mo produced by (n, gamma) method into the generator column; PZC is Mo adsorbent with practical performance for (n, gamma) 99m Tc generator with high 99 Mo adsorption and high 99m Tc elution. For conducting the constant supply and delivery of 99m Tc generator, it is necessary to establish the technology of (n, gamma) method 99m Tc generator using PZC and to develop the fabrication system for 99 Mo loading to PZC and packing the 99m Tc generator column. By the reason, we are developing the Mo loading apparatus. In order to automatically conduct the process of 99 Mo adsorption to PZC and PZC- 99 Mo packing into the generator column, based on one channel system developed by JAERI-KAKEN at 3 years ago, an advanced automatic loading system functioned with 8 channels was developed as FNCA project proceeded by the core with Kaken Co. and JAIF for realizing a mass production of 99m Tc generators, and moreover the Japanese patent regarding the PZC- 99m Tc generator including the automatic loading system of 99 Mo to PZC and making 99m Tc generator columns has already been applied with joint applicants of BATAN and Kaken Co. Regarding the multi-type Mo loading apparatus mentioned above, we set it up in a hot of BATAN at December 2003 year. In this report, we will introduce mainly about the multi-channel automatic loading system of 99 Mo. (author)

Installation of Tc-99m generator manufacturing facilities

International Nuclear Information System (INIS)

Shin, B. C.; Choung, W. M.; Park, J. H.; Park, S. H.; Kim, S. J.; Park, K. B.

2004-01-01

For the characteristics of radiopharmaceuticals, the manufacturing facility should be complied with the radiation safety standards for operators as well as GMP (Good Manufacturing Practice) cleanness standards for production. We intensively modified the existing Radioisotope production facilities, which were installed only in radiation safety points of view, to meet cleanness criteria. And the concept of multi-barrier buffer zones was introduced to apply negative air pressure for hot cell with first priority and to continue relative positive air pressure for clean room. The manufacturing area for Tc-99m Generator can be entered only through a second change. The doors of each change area are interlocked to maintain air pressure differentials. The pass box for material transfer are also interlocked so that only one side may be opened at any one time to keep cleanness. Two door-type autoclave was installed crossing the wall between preparing room and aseptic room to keep cleanness after sterilization. Three lead hot cells were installed and final inspection including gamma survey test were performed. The clean room was installed and TAB for this facility was performed in order to acquire the necessary air flow. The filter bank for filtration of exhausted radiation air was installed and its efficiency test was performed. In this facility, radiation shielding utilities and manufacturing instruments were set up and their operating manuals were documented. Efficiency tests for every utilities and instruments were satisfied and the approval for use of the facilities was achieved from MOST (Ministry of Science and Technology). The Sam Young Unitech, the lessee of the facilities set up the equipment in the hot cell, which is needed to produce Tc-99m Generator, supported by IPPE in Russia. They are composing the systems complied with the guidelines and the regulations, and keep in contact to KFDA for acquiring its approval. It is expected to produce Tc-99m Generator within

Microbial reduction of 99Tc (as TcO4-) in anaerobic alkaline conditions

International Nuclear Information System (INIS)

Khizhnyak, T.; Simonoff, M.; Sergeant, C.; Simonoff, G.; Medvedeva-Lyalikova, N.N.

2003-01-01

The ability of bacteria to reduce pertechnetate in alkaline conditions was investigated using halophilic bacteria isolated from soda-lakes environments. Anaerobic halophilic bacteria were able to reduce as much as 0.25 mM pertechnetate, whereas no reduction took place without bacteria or in the presence of heat-killed bacteria. The results obtained showed reduction of Tc(VII)O 4 - to the Tc(V) and Tc(IV) at pH 10 in the carbonate-bicarbonate medium. About 57% of the total technetium was determined to be Tc(IV), 1-3% as a Tc(V) and 17-20% as a Tc(VII) after 1-3 days of incubation with bacteria. The microbial reduction of Tc(VII) in alkaline conditions has been suggested as a potential mechanism for the removal of Tc from contaminated environments or waste streams. (author)

Extended abstracts of the 12th JAERI workshop on high-Tc superconductors

Energy Technology Data Exchange (ETDEWEB)

Hojou, Kiichi; Okayasu, Satoru; Sasase, Masato [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ishida, Takekazu [Osaka Prefectual Univ., Sakai (JP)] (eds.)

2001-03-01

This workshop was held on December 7-8, 2000 at JAERI (Tokai). The research group at JAERI shares a responsibility for material modification of high-Tc superconductors by irradiation in 'the multi-core project II of the high temperature superconducting material research' organized by STA (Science and Technology Agency) of Japan. This report contains the extended abstracts of workshop presentations covering basic theories, various experimental results and material improvement studies of the superconductivity by high energy ion irradiation. The twelve presentations of the workshop were devoted to a mini symposium where the direct observations of vortices were discussed in view of the various sophisticated techniques. (author)

Extended abstracts of the 12th JAERI workshop on high-Tc superconductors

International Nuclear Information System (INIS)

Hojou, Kiichi; Okayasu, Satoru; Sasase, Masato

2001-03-01

This workshop was held on December 7-8, 2000 at JAERI (Tokai). The research group at JAERI shares a responsibility for material modification of high-Tc superconductors by irradiation in 'the multi-core project II of the high temperature superconducting material research' organized by STA (Science and Technology Agency) of Japan. This report contains the extended abstracts of workshop presentations covering basic theories, various experimental results and material improvement studies of the superconductivity by high energy ion irradiation. The twelve presentations of the workshop were devoted to a mini symposium where the direct observations of vortices were discussed in view of the various sophisticated techniques. (author)

The function of Sn(II)-apatite as a Tc immobilizing agent

Energy Technology Data Exchange (ETDEWEB)

Asmussen, R. Matthew, E-mail: matthew.asmussen@pnnl.gov [Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99352 (United States); Neeway, James J.; Lawter, Amanda R.; Levitskaia, Tatiana G. [Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99352 (United States); Lukens, Wayne W. [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720 (United States); Qafoku, Nikolla P. [Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99352 (United States)

2016-11-15

At the U.S. Department of Energy Hanford Site, Tc-99 is a component of low-activity waste (LAW) fractions of the nuclear tank waste and removal of Tc from LAW streams would greatly benefit the site remediation process. In this study, we investigated the removal of Tc(VII), as pertechnetate, from deionized water (DIW) and a LAW simulant through batch sorption testing and solid phase characterization using tin (II) apatite (Sn-A) and SnCl{sub 2}. Sn-A showed higher levels of Tc removal from both DIW and LAW simulant. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/XEDS) and X-ray absorption spectroscopy (XAS) of reacted Sn-A in DIW showed that TcO4- is reduced to Tc(IV) on the Sn-A surface. The performance of Sn-A in the LAW simulant was lowered due to a combined effect of the high alkalinity, which lead to an increased dissolution of Sn from the Sn-A, and a preference for the reduction of Cr(VI). - Highlights: • Sn(II)-Apatite shows high proficiency in removing Tc(VII) from neutral solutions. • The removal of the Tc(VII) by Sn(II)-apatite is done via reduction to Tc(IV)O{sub 2} × H{sub 2}O. • In LAW Sn(II)-apatite is less efficient in removing Tc(VII). • Interference in LAW due to a preference for the reduction of Cr(VI) and the high pH. • Sn(II)-apatite can remove Tc(VII) from LAW effectively through increasing material added.

Towards a complete Fermi surface in underdoped high Tc superconductors

Science.gov (United States)

Harrison, Neil

The discovery of magnetic quantum oscillations in underdoped high Tc superconductors raised many questions, and initiated a quest to understand the origin of the Fermi surface the like of which had not been seen since the very first discovery of quantum oscillations in elemental bismuth. While studies of the Fermi surface of materials are today mostly assisted by computer codes for calculating the electronic band structure, this was not the case in the underdoped high Tc materials. The Fermi surface was shown to reconstructed into small pockets, yet there was no hint of a viable order parameter. Crucial clues to understanding the origin of the Fermi surface were provided by the small value of the observed Fermi surface cross-section, the negative Hall coefficient and the small electronic heat capacity at high magnetic fields. We also know that the magnetic fields were likely to be too weak to destroy the pseudogap and that vortex pinning effects could be seen to persist to high magnetic fields at low temperatures. I will show that the Fermi surface that appears to fit best with the experimental observations is a small electron pocket formed by connecting the nodal `Fermi arcs' seen in photoemission experiments, corresponding to a density-wave state with two different orthogonal ordering vectors. The existence of such order has subsequently been detected by x-ray scattering experiments, thereby strengthening the case for charge ordering being responsible for reconstructing the Fermi surface. I will discuss new efforts to understand the relationship between the charge ordering and the pseudogap state, discussing the fate of the quasiparticles in the antinodal region and the dimensionality of the Fermi surface. The author acknowledges contributions from Suchitra Sebastian, Brad Ramshaw, Mun Chan, Yu-Te Hsu, Mate Hartstein, Gil Lonzarich, Beng Tan, Arkady Shekhter, Fedor Balakirev, Ross McDonald, Jon Betts, Moaz Altarawneh, Zengwei Zhu, Chuck Mielke, James Day, Doug

Graphene shield enhanced photocathodes and methods for making the same

Science.gov (United States)

Moody, Nathan Andrew

2014-09-02

Disclosed are graphene shield enhanced photocathodes, such as high QE photocathodes. In certain embodiments, a monolayer graphene shield membrane ruggedizes a high quantum efficiency photoemission electron source by protecting a photosensitive film of the photocathode, extending operational lifetime and simplifying its integration in practical electron sources. In certain embodiments of the disclosed graphene shield enhanced photocathodes, the graphene serves as a transparent shield that does not inhibit photon or electron transmission but isolates the photosensitive film of the photocathode from reactive gas species, preventing contamination and yielding longer lifetime.

Superconductivity in the W-Tc and W2C-Tc systems

International Nuclear Information System (INIS)

Giorgi, A.L.

1985-01-01

A series of compositions in the W-Tc, W 2 C-Re and W 2 C-Tc systems were prepared and examined for superconductivity. The crystal structure, lattice parameters and superconducting transition temperatures of the W 2 C-Tc are reported for the first time. Similar measurements were made on the W-Tc and W 2 C-Re systems and the results compared with previous published results for these systems. 7 refs., 2 figs., 2 tabs

On the interaction of granite with Tc(IV) and Tc(VII) in aqueous solution

International Nuclear Information System (INIS)

Eriksen, T.E.; Cui, Daquing

1991-10-01

The behaviour of technetium in granite-groundwater systems under reducing conditions was investigated. The anion TcO 4 - was reduced to Tc(IV) and simultaneously precipitated as TcO 2 xnH 2 O on the granite surfaces. The electron sources are assumed to be iron oxides and/or iron containing minerals in the granite. The technetium concentration in ground water under repository conditions may be predicted assuming TcO 2 xnH 2 O as the solid phase and TcO(OH) 2 0 and TcO 4 - as the predominant aqueous complexes using a formation constant for TcO(OH) 2 0 of log K = -8.16 and a standard reduction potential E 0 for the reaction TcO 4 - + 3e - + 4H + = TcO 2 xnH 2 O of 0.738 V. The surface related distribution ratio K a for TcO(OH) 2 0 between Stripa granite and ground water is approximately 1 cm based on geometrical surface area. (au)

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.

Cytological effects of Tc on young soybean plants

International Nuclear Information System (INIS)

Neel, J.W.; Onasch, M.A.

1989-01-01

Soybean seedlings (Glycine max cv. Williams) were exposed for 24 to 67 h to 99 TcO 4 - (Tc) at various concentrations in dilute culture solution. Reduced primary leaf midrib length was observed with 67-h exposures to greater than or equal to 6.0 mu M Tc. Cellular effects were consistently observed by a light microscope after 43-h or longer exposure to 6.6 microM Tc and higher concentrations. At lower Tc levels, abnormal cells were interspersed among cells of normal appearance. Abnormal cells displayed blockshaped nuclei which were more densely stained by Harris' hematoxylineosin Y than controls; such cells frequently demonstrated incipient plasmolysis. The number of affected cells increased with dose; both nuclei and cytoplasm demonstrated greater staining intensity and more severe plasmolysis at higher levels. At levels of greater than or equal to 13.2 Tc, cellular damage was extensive. Cells were reduced in size and were highly plasmolysed; cell walls were distorted, and intercellular spaces were reduced or became nonexistent. Mitotic activity was observed at Tc levels less than or equal to 9.9 microM. Observed Tc cellular effects are attributed principally to the alteration of membrane permeability characteristics

Neutron shielding material based on colemanite and epoxy resin

International Nuclear Information System (INIS)

Okuno, K.

2005-01-01

In recent years, there has been a need for compact shielding design such as self-shielding of a PET cyclotron or up-gradation of radiation machinery in existing facilities. In these cases, high performance shielding materials are needed. Concrete or polyethylene have been used for a neutron shield. However, for compact shielding, they fall short in terms of performance or durability. Therefore, a new type of neutron shielding material based on epoxy resin and colemanite has been developed. Slab attenuation experiments up to 40 cm for the new shielding material were carried out using a 252 Cf neutron source. Measurement was carried out using a REM-counter, and compared with calculation. The results show that the shielding performance is better than concrete and polyethylene mixed with 10 wt% boron oxide. From the result, we confirmed that the performance of the new material is suitable for practical use. (authors)

Transparent fast neutron shielding material and shielding method

International Nuclear Information System (INIS)

Nashimoto, Tetsuji; Katase, Haruhisa.

1993-01-01

Polyisobutylene having a viscosity average molecular weight of 20,000 to 80,000 and a hydrogen atom density of greater than 7.0 x 10 22 /cm 3 is used as a fast neutron shielding material. The shielding material is excellent in the shielding performance against fast neutrons, and there is no worry of leakage even when holes should be formed to a vessel. Further, it is excellent in fabricability, relatively safe even upon occurrence of fire and, in addition, it is transparent to enable to observe contents easily. (T.M.)

Electromagnetically shielded building

Energy Technology Data Exchange (ETDEWEB)

Takahashi, T; Nakamura, M; Yabana, Y; Ishikawa, T; Nagata, K

1992-04-21

This invention relates to a building having an electromagnetic shield structure well-suited for application to an information network system utilizing electromagnetic waves, and more particularly to an electromagnetically shielded building for enhancing the electromagnetic shielding performance of an external wall. 6 figs.

Electromagnetically shielded building

International Nuclear Information System (INIS)

Takahashi, T.; Nakamura, M.; Yabana, Y.; Ishikawa, T.; Nagata, K.

1992-01-01

This invention relates to a building having an electromagnetic shield structure well-suited for application to an information network system utilizing electromagnetic waves, and more particularly to an electromagnetically shielded building for enhancing the electromagnetic shielding performance of an external wall. 6 figs

Comparative biological evaluation between 99mTc tricarbonyl and 99mTc-Sn(II) levosalbutamol as a β2-adrenoceptor agonist

International Nuclear Information System (INIS)

Sanad, Mahmoud H.; Borai, Emad H.

2015-01-01

This study describes the comparison between 99m Tc-tricarbonyl and 99m Tc-Sn (II) levosalbutamol as a β 2 -adrenoceptors radiopharmaceutical and evaluation of their different biological characteristics using experimental animals. Levosalbutamol was labeled firstly with 99m Tc in the presence of SnCl 2 . 2H 2 O as a reducing agent under the optimum conditions: pH 8, 50 μg SnCl 2 . 2H 2 O, room temperature, 40 μg levosalbutamol and 30 min reaction time to give a maximum radiochemical yield of 98 ± 0.1%. The obtained 99m Tc-levosalbutamol was stable for a time up to 8 h. Secondly, 99m Tc-tricarbonyl ([ 99m Tc(CO) 3 (H 2 O) 3 ] + ) levosalbutamol was prepare under 30 min heating at 100 C. Labeling yield and stability were analyzed by high performance liquid chromatography (labeling yield >99% and stability for 8 h). Biodistribution investigation showed that, the maximum uptake ratio of the 99m Tc-levosalbutamol ( 99m Tc-Lev) between lung and heart was 2.34 ± 0.62 % of the injected activity/g tissue organ, at 30 min post-injection. But in case of 99m Tc-tricarbonyl levosalbutamol ( 99m Tc-tricarbonyl Lev) the maximum uptake ratio was 3.6 ± 0.11 of the injected activity/g tissue organ, at 30 min post-injection. This indicates that 99m Tc-tricarbonyl levosalbutamol was more selective for lung β 2 -adrenoceptors than 99m Tc-levosalbutamol. These results introduce 99m Tc-tricarbonyl levosalbutamol as a novel potential radiopharmaceutical for lung imaging.

Radiation shielding for fission reactors

Energy Technology Data Exchange (ETDEWEB)

Oka, Yoshiaki [Tokyo Univ., Nuclear Engineering Research Laboratory, Tokyo (Japan)

2000-03-01

Radiation shielding aspects relating fission reactors have been reviewed. Domestic activities in the past five years have been mainly described concerning nuclear data, calculation methods, shielding and skyshine experiments, Advanced Boiling Water Reactor (ABWR), Advanced Pressurized Water Reactor (APWR), High Temperature Engineering Test Reactor (HTTR), Experimental and Prototype Fast Reactors (JOYO, MONJU), Demonstration FBR, core shroud replacement of BWR, and spent fuel transportation cask and vessel. These studies have valuable information in safety and cost reduction issues of fission reactor design for not only existing reactors but also new reactor concepts in the next century. It has been concluded that we should maintain existing shielding technologies and improve these data and methods for coming generations in the next millennium. (author)

Radiation shielding concrete

International Nuclear Information System (INIS)

Kunishima, Shigeru.

1990-01-01

The radiation shielding concretes comprise water, cement, fine aggregates consisting of serpentines and blown mist slags, coarse aggregates consisting of serpentines and kneading materials. Since serpentines containing a relatively great amount of water of crystallization in rocks as coarse aggregates and fine aggregates, the hydrogen content in the radiation shielding concretes is increased and the neutron shielding effect is improved. In addition, since serpentines are added as the fine aggregates and blown mists slags of a great specific gravity are used, the specific gravity of the shielding concretes is increased to improve the γ-ray shielding effect. Further, by the use of the kneading material having a water reducing effect and fluidizing effect, and by the bearing effect of the spherical blown mist slags used as the fine aggregates, concrete fluidity can be increased. Accordingly, workability of the radiation shielding concretes can be improved. (T.M.)

Mechanochemical effects on high-Tc superconductor powders

International Nuclear Information System (INIS)

Yamada, Taichi; Nagai, Ryoji; Takeuchi, Manabu; Minehara, Eisuke.

1991-03-01

We have investigated the mechanochemical effects on high-Tc superconductor (YBa 2 Cu 3 O 7 -δ) powders. The powder was mechanically ground in air using an agate mortar with a pestle. The grinding time was varied from 2 to 100 min. The mean particle sizes of the powders were measured by a sedimentation method. The degradation of superconductivity was evaluated by the measurements of the crystallinity and volume fraction of the superconducting phase. The crystallinity was estimated from X-ray diffraction patterns. The volume fraction of the superconducting phase was estimated from the diamagnetization. The results of these changes of 2 min. and 100 min. grinding are respectively as follows; 1) mean particle size: 10.8 μm and 7.2 μm, 2) crystallinity: 40.0 % and 24.8 %, 3) volume fraction of superconducting phase: 91.5 % and 30.0 %. Recovery of the crystallinity and superconductivity of the ground specimens by re-sintering and re-annealing was also studied. It was found that the recovery of both of the characteristics was not complete. (author)

High-temperature superconducting conductors and cables

International Nuclear Information System (INIS)

Peterson, D.E.; Maley, M.P.; Boulaevskii, L.; Willis, J.O.; Coulter, J.Y.; Ullmann, J.L.; Cho, Jin; Fleshler, S.

1996-01-01

This is the final report of a 3-year LDRD project at LANL. High-temperature superconductivity (HTS) promises more efficient and powerful electrical devices such as motors, generators, and power transmission cables; however this depends on developing HTS conductors that sustain high current densities J c in high magnetic fields at temperatures near liq. N2's bp. Our early work concentrated on Cu oxides but at present, long wire and tape conductors can be best made from BSCCO compounds with high J c at low temperatures, but which are degraded severely at temperatures of interest. This problem is associated with thermally activated motion of magnetic flux lines in BSCCO. Reducing these dc losses at higher temperatures will require a high density of microscopic defects that will pin flux lines and inhibit their motion. Recently it was shown that optimum defects can be produced by small tracks formed by passage of energetic heavy ions. Such defects result when Bi is bombarded with high energy protons. The longer range of protons in matter suggests the possibility of application to tape conductors. AC losses are a major limitation in many applications of superconductivity such as power transmission. The improved pinning of flux lines reduces ac losses, but optimization also involves other factors. Measuring and characterizing these losses with respect to material parameters and conductor design is essential to successful development of ac devices

Organic-inorganic hybrid optical foils with strong visible reflection, excellent near infrared-shielding ability and high transparency

Science.gov (United States)

Zhou, Yijie; Huang, Aibin; Zhou, Huaijuan; Ji, Shidong; Jin, Ping

2018-03-01

Research on functional flexible films has recently been attracting widespread attention especially with regards to foils, which can be designed artificially on the basis of the practical requirements. In this work, a foil with high visible reflection and a strong near infrared shielding efficiency was prepared by a simple wet chemical method. In the process of making this kind of optical foil, emulsion polymerization was first introduced to synthesize polymer opals, which were further compressed between two pieces of polyethylene terephthalate (PET) foil under polymer melting temperature to obtain a photonic crystal film with a strong reflection in the visible region to block blue rays. The following step was to coat a layer of the inorganic nano paint, which was synthesized by dispersing Cs-doped WO3 (CWO) nanoparticles homogenously into organic resin on the surface of the PET to achieve a high near infrared shielding ability. The final composite foil exhibited unique optical properties such as high visible reflectance (23.9%) to block blue rays, and excellent near infrared shielding efficiency (98.0%), meanwhile it still maintained a high transparency meaning that this foil could potentially be applied in energy-saving window films. To sum up, this study provides new insight into devising flexible hybrid films with novel optical properties, which could be further extended to prepare other optical films for potential use in automobile, architectural and other decorative fields.

Design report for shielded glove box

International Nuclear Information System (INIS)

Ku, J. H.; Lee, J. C.; Seo, K. S.; Bang, K. S.; Lee, D. W.; Kim, J. H.; Min, D. K.; Park, S. W.

1999-05-01

For the examination of spent fuels and high radioactive specimens using a specially equipped scanning electron microscope, a shielded glove box was designed and constructed at PIE facility of KAERI. This glove box consisted of shielding walls, containment box, lead glasses, manipulators, gloves, ventilation systems, doors, hot-cell specimen cask adapter, etc. It was emphasized that both the easy operation and radiation safety are important factors in the shielded glove box were installed also considered as a important factor to build the basic concept of the assembling. Two sliding doors and one hinge-type door were installed for the easy installation, operation and maintenance of scanning electron microscope. Containment box which confines the radioactive material into the box consisted of reinforced transparent glasses, aluminum frames and stainless steel plate liner. Therefore everything beyond the containment box can be seen through the lead glass which installed at the front shielding wall. All shielding walls and doors were introduced separately into the room and assembled by bolting. (author). 3 refs., 5 tabs., 18 figs

High-{Tc} superconducting antenna-coupled microbolometer on silicon

Energy Technology Data Exchange (ETDEWEB)

Rice, J.P.; Grossman, E.N.; Borcherdt, L.J.; Rudman, D.A. [National Inst. of Standards and Technology, Boulder, CO (United States). Cryoelectronic Metrology Group

1994-12-31

A process is described for fabricating antenna-coupled resistive-edge microbolometers based on the high-{Tc} superconductor YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) on silicon. The YBCO and a buffer layer of yttria-stabilized zirconia (YSZ) were grown epitaxially on silicon to minimize excess electrical noise. A silicon-micromachined YBCO/YSZ air-bridge was incorporated to minimize the thermal conductance and the heat capacity. The thermal conductance of the air-bridge was measured to be 3 {times} 10{sup {minus}6} W/K at a temperature of 100 K. At an operating temperature of 89 K, the detector is estimated to have a response time of 2 {micro}s, a responsivity in the 1,000 V/W range, and a noise-equivalent power (NEP) in the 10{sup {minus}12} W/Hz{sup 1/2} range at 1,000 Hz.

Determination of the angular dependence of Hc2 in high Tc single crystals by a microwave technique

OpenAIRE

Shaltiel, David; Bill, Hans; Grayevsky, A.; Junod, Alain; Lovy, Dominique; Sadowski, S.; Walker, Eric

1991-01-01

It is shown that using an ESR spectrometer with magnetic field modulation and sweeping the temperature across Tc (at a constant and a very low magnetic field), is equivalent to temperature modulation. The signal intensity obtained when crossing Tc is proportional to 1/( delta Hc2/ delta T) at T=Tc. Using the WHH relation Hc2(T=0)=0.7 Tc( delta Hc2/ delta T)T=Tc enabled the measurement of the relative angular variation of Hc2 in single crystals of YBaCuO with Tc approximately 85 K. The data fi...

Safety guide data on radiation shielding in a reprocessing facility

International Nuclear Information System (INIS)

Sekiguchi, Noboru; Naito, Yoshitaka

1986-04-01

In a reprocessing facility, various radiation sources are handled and have many geometrical conditions. To aim drawing up a safety guidebook on radiation shielding in order to evaluate shielding safety in a reprocessing facility with high reliability and reasonableness, JAERI trusted investigation on safety evaluation techniques of radiation shielding in a reprocessing facility to Nuclear Safety Research Association. This report is the collection of investigation results, and describes concept of shielding safety design principle, radiation sources in reprocessing facility and estimation of its strength, techniques of shielding calculations, and definite examples of shielding calculation in reprocessing facility. (author)

Potential of Nanocellulose Composite for Electromagnetic Shielding

Directory of Open Access Journals (Sweden)

Nabila Yah Nurul Fatihah

2017-01-01

Full Text Available Nowadays, most people rely on the electronic devices for work, communicating with friends and family, school and personal enjoyment. As a result, more new equipment or devices operates in higher frequency were rapidly developed to accommodate the consumers need. However, the demand of using wireless technology and higher frequency in new devices also brings the need to shield the unwanted electromagnetic signals from those devices for both proper operation and human health concerns. This paper highlights the potential of nanocellulose for electromagnetic shielding using the organic environmental nanocellulose composite materials. In addition, the theory of electromagnetic shielding and recent development of green and organic material in electromagnetic shielding application has also been reviewed in this paper. The use of the natural fibers which is nanocelllose instead of traditional reinforcement materials provides several advantages including the natural fibers are renewable, abundant and low cost. Furthermore, added with other advantages such as lightweight and high electromagnetic shielding ability, nanocellulose has a great potential as an alternative material for electromagnetic shielding application.

Evolution of 99Tc Species in Cementitious Nuclear Waste Form

International Nuclear Information System (INIS)

Um, Woo Yong; Westsik, Joseph H.

2011-01-01

Technetium (Tc) is produced in large quantities as a fission product during the irradiation of 235 U-enriched fuel for commercial power production and plutonium genesis for nuclear weapons. The most abundant isotope of Tc present in the wastes is 99 Tc because of its high fission yield (∼6%) and long half-life (2.13x10 5 years). During the Cold War era, generation of fissile 239 Pu for use in America's atomic weapons arsenal yielded nearly 1900 kg of 99 Tc at the U.S. Department of Energy's (DOE) Hanford Site in southeastern Washington State. Most of this 99 Tc is present in fuel reprocessing wastes temporarily stored in underground tanks awaiting retrieval and permanent disposal. After the wastes are retrieved from the storage tanks, the bulk of the high-level waste (HLW) and lowactivity waste (LAW) stream is scheduled to be converted into a borosilicate glass waste form that will be disposed of in a shallow burial facility called the Integrated Disposal Facility (IDF) at the Hanford Site. Even with careful engineering controls, volatilization of a fraction of Tc during the vitrification of both radioactive waste streams is expected. Although this volatilized Tc can be captured in melter off-gas scrubbers and returned to the melter, some of the Tc is expected to become part of the secondary waste stream from the vitrification process. The off-gas scrubbers downstream from the melters will generate a high pH, sodium-ammonium carbonate solution containing the volatilized Tc and other fugitive species. Effective and cost-efficient disposal of Tc found in the off-gas scrubber solution remains difficult. A cementitious waste form (Cast Stone) is one of the nuclear waste form candidates being considered to solidify the secondary radioactive liquid waste that will be generated by the operation of the waste treatment plant (WTP) at the Hanford Site. Because Tc leachability from the waste form is closely related with Tc speciation or oxidation state in both the simulant

Analysis of accumulation of 99mTc-octreotide and 99mTc-EDDA/HYNIC-Tyr3-octreotide in the rat kidneys.

Science.gov (United States)

Kopecky, Martin; Semecky, Vladimir; Trejtnar, Frantisek; Laznicek, Milan; Laznickova, Alice; Nachtigal, Petr; Decristoforo, Clemens; Mather, Stephen J; Mäcke, Helmut R

2004-02-01

The aim of this study was to compare renal handling and distribution of (99m)Tc-octreotide and (99m)Tc-EDDA/HYNIC-Tyr(3)-octreotide (HYNIC-TOC) in rats. In kidney perfusion experiments, the renal clearance value of (99m)Tc-octreotide was three times lower than that of (99m)Tc-EDDA/HYNIC-TOC. The predominant renal excretion of (99m)Tc-EDDA/HYNIC-TOC was associated with a high and long-term renal accumulation up to 48 hrs. Microautoradiographic results indicated that (99m)Tc-EDDA/HYNIC-TOC was retained mainly in the renal medulla within the cells of the collecting ducts and in the surrounding tissue. Lower positivity was found in the proximal and distal tubular cells. We conclude that the mechanism of renal accumulation of somatostatin analogues renal accumulation is complex and that proximal tubular reabsorption is probably not the main mechanism for uptake of (99m)Tc-EDDA/HYNIC-TOC in the kidneys. The presence of the somatostatin receptors, differences in the tonicity level within kidneys and other possible mechanisms could participate in their renal accumulation.

Analysis of accumulation of 99mTc-octreotide and 99mTc-EDDA/HYNIC-Tyr3-octreotide in the rat kidneys

International Nuclear Information System (INIS)

Kopecky, Martin; Semecky, Vladimir; Trejtnar, Frantisek; Laznicek, Milan; Laznickova, Alice; Nachtigal, Petr; Decristoforo, Clemens; Mather, Stephen J.; Maecke, Helmut R.

2004-01-01

The aim of this study was to compare renal handling and distribution of 99m Tc-octreotide and 99m Tc-EDDA/HYNIC-Tyr 3 -octreotide (HYNIC-TOC) in rats. In kidney perfusion experiments, the renal clearance value of 99m Tc-octreotide was three times lower than that of 99m Tc-EDDA/HYNIC-TOC. The predominant renal excretion of 99m Tc-EDDA/HYNIC-TOC was associated with a high and long-term renal accumulation up to 48 hrs. Microautoradiographic results indicated that 99m Tc-EDDA/HYNIC-TOC was retained mainly in the renal medulla within the cells of the collecting ducts and in the surrounding tissue. Lower positivity was found in the proximal and distal tubular cells. We conclude that the mechanism of renal accumulation of somatostatin analogues renal accumulation is complex and that proximal tubular reabsorption is probably not the main mechanism for uptake of 99m Tc-EDDA/HYNIC-TOC in the kidneys. The presence of the somatostatin receptors, differences in the tonicity level within kidneys and other possible mechanisms could participate in their renal accumulation

A New Microwave Shield Preparation for Super High Frequency Range: Occupational Approach to Radiation Protection.

Science.gov (United States)

Zaroushani, Vida; Khavanin, Ali; Jonidi Jafari, Ahmad; Mortazavi, Seyed Bagher

2016-01-01

Widespread use of X-band frequency (a part of the super high frequency microwave) in the various workplaces would contribute to occupational exposure with potential of adverse health effects.  According to limited study on microwave shielding for the workplace, this study tried to prepare a new microwave shielding for this purpose. We used EI-403 epoxy thermosetting resin as a matrix and nickel oxide nanoparticle with the diameter of 15-35 nm as filler. The Epoxy/ Nickel oxide composites with 5, 7, 9 and 11 wt% were made in three different thicknesses (2, 4 and 6 mm). According to transmission / reflection method, shielding effectiveness (SE) in the X-band frequency range (8-12.5 GHz) was measured by scattering parameters directly given by the 2-port Vector Network Analyzer. The fabricated composites characterized by X-ray Diffraction and Field Emission Scanning Electron Microscope. The best average of shielding effectiveness in each thickness of fabricated composites obtained by 11%-2 mm, 7%-4 mm and 7%-6 mm composites with SE values of 46.80%, 66.72% and 64.52%, respectively. In addition, the 11%-6 mm, 5%-6 mm and 11%-4 mm-fabricated composites were able to attenuate extremely the incident microwave energy at 8.01, 8.51 and 8.53 GHz by SE of 84.14%, 83.57 and 81.30%, respectively. The 7%-4mm composite could be introduced as a suitable alternative microwave shield in radiation protection topics in order to its proper SE and other preferable properties such as low cost and weight, resistance to corrosion etc. It is necessary to develop and investigate the efficacy of the fabricated composites in the fields by future studies.

/sup 99m/Tc-aminohexylidendiphosphonate and /sup 99/mTc-Pyrophosphate in the scintigraphic diagnosis of experimental cardiomyopathy in dogs

Energy Technology Data Exchange (ETDEWEB)

Duska, F; Kafka, P; Mazurova, Y; Hadas, L; Vizda, J; Palicka, V; Grossman, V

1987-10-01

Experimental cardiomyopathy was provoked in 24 dogs with high intravenous doses of adrenaline and theophylline. These lesions were studied by means of the new agent /sup 99m/Tc-AHDP and /sup 99m/Tc-PYP in comparison. Cardiomyopathy could be imaged as early as 4 h after the onset of involvement but not later than 7 days. A maximum accumulation occurred in lesions 24 h old, /sup 99m/Tc uptake in the myocardium was graded scintigraphically, /sup 99m/Tc-AHDP was accumulated in the altered myocardium to a greater extent than /sup 99m/Tc-PYP. Scintigraphic findings were in good agreement with plasma levels of creatine-kinase. A comparison with histology demonstrated that the maximum accumulation of radiopharmaceuticals occurred at the time when the development of myocardium involvement reached the stage of myocytolysis.

Wake Shield Target Protection

International Nuclear Information System (INIS)

Valmianski, Emanuil I.; Petzoldt, Ronald W.; Alexander, Neil B.

2003-01-01

The heat flux from both gas convection and chamber radiation on a direct drive target must be limited to avoid target damage from excessive D-T temperature increase. One of the possibilities of protecting the target is a wake shield flying in front of the target. A shield will also reduce drag force on the target, thereby facilitating target tracking and position prediction. A Direct Simulation Monte Carlo (DSMC) code was used to calculate convection heat loads as boundary conditions input into ANSYS thermal calculations. These were used for studying the quality of target protection depending on various shapes of shields, target-shield distance, and protective properties of the shield moving relative to the target. The results show that the shield can reduce the convective heat flux by a factor of 2 to 5 depending on pressure, temperature, and velocity. The protective effect of a shield moving relative to the target is greater than the protective properties of a fixed shield. However, the protective effect of a shield moving under the drag force is not sufficient for bringing the heat load on the target down to the necessary limit. Some other ways of diminishing heat flux using a protective shield are discussed

Accuracy of 99Molybdenum assays in /sup 99m/Technetium solutions

International Nuclear Information System (INIS)

Williams, C.C.; Kereiakes, J.G.; Grossman, L.W.

1981-01-01

A study was performed to determine the accuracy of 99 Mo measurements using three commercial dose calibrators with their 99 Mo assay shields. One 99 Mo assay shield allowed excessive penetration by the lower energy /sup 99m/Tc photons, resulting in the calibrator's falsely high interpretation of the activity of 99 Mo present in the high-activity /sup 99m/Tc eluates. All three calibrators performed adequately with a National Bureau of Standards 99 Mo standard in equilibrium with /sup 99m/Tc. By using low-activity aliquots of 99 Mo and /sup 99m/Tc, a low-level linearity test was performed. Only one of the calibrators was found to reflect accurately the activity of 99 Mo present under all conditions tested

Method for calculating required shielding in medical x-ray rooms

International Nuclear Information System (INIS)

Karppinen, J.

1997-10-01

The new annual radiation dose limits - 20 mSv (previously 50 mSv) for radiation workers and 1 mSv (previously 5 mSv) for other persons - implies that the adequacy of existing radiation shielding must be re-evaluated. In principle, one could assume that the thicknesses of old radiation shields should be increased by about one or two half-value layers in order to comply with the new dose limits. However, the assumptions made in the earlier shielding calculations are highly conservative; the required shielding was often determined by applying the maximum high-voltage of the x-ray tube for the whole workload. A more realistic calculation shows that increased shielding is typically not necessary if more practical x-ray tube voltages are used in the evaluation. We have developed a PC-based calculation method for calculating the x-ray shielding which is more realistic than the highly conservative method formerly used. The method may be used to evaluate an existing shield for compliance with new regulations. As examples of these calculations, typical x-ray rooms are considered. The lead and concrete thickness requirements as a function of x-ray tube voltage and workload are also given in tables. (author)

Proposal for the Award of Two Contracts for the Supply of High Temperature SuperconductingTape for the LHC

CERN Document Server

2003-01-01

This document concerns the award of two contracts for the supply of high temperature superconducting (HTS) BSCCO 2223 Ag-Au tape, of two different types, for the LHC. Following a call for tenders (IT-3143/AT/LHC) sent on 5 March 2003 to four firms in two Member States and one firm in the US, CERN received one tender from a firm in a Member State and one tender from the firm in the United States. The Finance Committee is invited to agree to the negotiation of contracts with: - VACUUMSCHMELZE (DE), for the supply of 17 km of HTS BSCCO 2223 Ag-Au tape with Ic > 66 A at 77 K for a total amount of 807 833 euros (1 201 900 Swiss francs), not subject to revision, with an option for the supply of up to additional 17 km of HTS BSCCO 2223 Ag-Au tape, for a total amount of up to 807 833 euros (1 201 900 Swiss francs), not subject to revision, bringing the total amount to a maximum of 1 615 666 euros (2 403 800 Swiss francs), not subject to revision. The rate of exchange used is that stipulated in the tender.

Software Tools for Measuring and Calculating Electromagnetic Shielding Effectiveness

National Research Council Canada - National Science Library

Tesny, Neal

2005-01-01

The evaluation and the analysis of high-altitude electromagnetic pulse response of shielded enclosures require the availability of software tools able to acquire data and calculate shielding effectiveness...

/sup 99m/Tc dextran: a new blood-pool-labeling agent for radionuclide angiocardiography

International Nuclear Information System (INIS)

Henze, E.; Robinson, G.D.; Kuhl, D.E.; Schelbert, H.R.

1982-01-01

We have explored the possibility of imaging the cardiac blood pool with dextran (Dx) labeled with /sup 99m/Tc (Tc) after Sn2+ reduction. Stannous dextran (SnDx) kits were prepared in advance and labeling was performed by adding /sup 99m/Tc. The labeling efficiency was greater than 95%. /sup 99m/Tc dextran (TcDx) was highly stable both in vivo and in vitro. In seven dogs we compared the quality of blood-pool images obtained with TcDx of different molecular weights (4 X 10(4) . Dx-40; 5 X 10(5) . Dx-500; 2 X 10(6) . Dx-2000) and with /sup 99m/Tc red blood cells (TcRBC) labeled in vitro, and determined the organ distribution of this new agent by whole-body scanning and blood sampling. TcDx provided high-quality cardiac blood-pool images up to 60 min after injection. The heart-to-lung ratios averaged 3.7 for TcDx-40, 3.9 for TcDx-500, and 5.4 for TcRBC at 60 min. Whereas TcDx-40 showed a relatively rapid initial urinary excretion and TcDx-2000 was degraded rapidly, TcDx-500 demonstrated the best kinetics for blood-pool imaging. Thus, TcDx is a new radiopharmaceutical with high labeling efficiency and stability. It overcomes a number of the limitations of currently used blood-labeling agents and may become useful for blood-pool imaging in man

Neutral and plasma shielding model for pellet ablation

International Nuclear Information System (INIS)

Houlberg, W.A.; Milora, S.L.; Attenberger, S.E.

1987-10-01

The neutral gas shielding model for ablation of frozen hydrogenic pellets is extended to include the effects of an initial Maxwelliam distribution of incident electron energies; a cold plasma shield outside the neutral shield and extended along the magnetic field; energetic neutral beam ions and alpha particles; and self-limiting electron ablation in the collisionless plasma limit. Including the full electron distribution increases ablation, but adding the cold ionized shield reduces ablation; the net effect is a modest reduction in pellet penetration compared with the monoenergetic electron neutral shielding model with no plasma shield. Unlike electrons, fast ions can enter the neutral shield directly without passing through the cold ionized shield because their gyro-orbits are typically larger than the diameter of the cold plasma tube. Fast alpha particles should not enhance the ablation rate unless their population exceeds that expected from local classical thermalization. Fast beam ions, however, may enhance ablation in the plasma periphery if their population is high enough. Self-limiting ablation in the collisionless limit leads to a temporary distortion of the original plasma electron Maxwellian distribution function through preferential depopulation of the higher-energy electrons. 23 refs., 9 figs

Optimal beta-ray shielding thicknesses for different therapeutic radionuclides and shielding materials

International Nuclear Information System (INIS)

Cho, Yong In; Kim, Ja Mee; Kim, Jung Hoon

2017-01-01

To better understand the distribution of deposited energy of beta and gamma rays according to changes in shielding materials and thicknesses when radionuclides are used for therapeutic nuclear medicine, a simulation was conducted. The results showed that due to the physical characteristics of each therapeutic radionuclide, the thicknesses of shielding materials at which beta-ray shielding takes place varied. Additional analysis of the shielding of gamma ray was conducted for radionuclides that emit both beta and gamma rays simultaneously with results showing shielding effects proportional to the atomic number and density of the shielding materials. Also, analysis of bremsstrahlung emission after beta-ray interactions in the simulation revealed that the occurrence of bremsstrahlung was relatively lower than theoretically calculated and varied depending on different radionuclides. (authors)

Comparison of Tc-99m maraciclatide and Tc-99m sestamibi molecular breast imaging in patients with suspected breast cancer.

Science.gov (United States)

O'Connor, Michael K; Morrow, Melissa M B; Hunt, Katie N; Boughey, Judy C; Wahner-Roedler, Dietlind L; Conners, Amy Lynn; Rhodes, Deborah J; Hruska, Carrie B

2017-12-01

Molecular breast imaging (MBI) performed with 99m Tc sestamibi has been shown to be a valuable technique for the detection of breast cancer. Alternative radiotracers such as 99m Tc maraciclatide may offer improved uptake in breast lesions. The purpose of this study was to compare relative performance of 99m Tc sestamibi and 99m Tc maraciclatide in patients with suspected breast cancer, using a high-resolution dedicated gamma camera for MBI. Women with breast lesions suspicious for malignancy were recruited to undergo two MBI examinations-one with 99m Tc sestamibi and one with 99m Tc maraciclatide. A radiologist interpreted MBI studies in a randomized, blinded fashion to assign an assessment score (1-5) and measured lesion size. Lesion-to-background (L/B) ratio was measured with region-of-interest analysis. Among 39 analyzable patients, 21 malignant tumors were identified in 21 patients. Eighteen of 21 tumors (86%) were seen on 99m Tc sestamibi MBI and 19 of 21 (90%) were seen on 99m Tc maraciclatide MBI (p = 1). Tumor extent measured with both radiopharmaceuticals correlated strongly with pathologic size ( 99m Tc sestamibi, r = 0.84; 99m Tc maraciclatide, r = 0.81). The L/B ratio in detected breast cancers was similar for the two radiopharmaceuticals: 1.55 ± 0.36 (mean ± S.D.) for 99m Tc sestamibi and 1.62 ± 0.37 (mean ± S.D.) for 99m Tc maraciclatide (p = 0.53). No correlation was found between the L/B ratio and molecular subtype for 99m Tc sestamibi (r s  = 0.12, p = 0.63) or 99m Tc maraciclatide (r s  = -0.12, p = 0.64). Of 20 benign lesions, 10 (50%) were seen on 99m Tc sestamibi and 9 of 20 (45%) were seen on 99m Tc maraciclatide images (p = 0.1). The average L/B ratio for benign lesions was 1.34 ±0.40 (mean ±S.D.) for 99m Tc sestamibi and 1.41 ±0.52 (mean ±S.D.) for 99m Tc maraciclatide (p = 0.75). Overall diagnostic performance was similar for both radiopharmaceuticals. AUC from ROC

Comprehensive analysis of shielding effectiveness for HDPE, BPE and concrete as candidate materials for neutron shielding

International Nuclear Information System (INIS)

Dhang, Prosenjit; Verma, Rishi; Shyam, Anurag

2015-01-01

In the compact accelerator based DD neutron generator, the deuterium ions generated by the ion source are accelerated after the extraction and bombarded to a deuterated titanium target. The emitted neutrons have typical energy of ∼2.45MeV. Utilization of these compact accelerator based neutron generators of yield up to 10 9 neutron/second (DD) is under active consideration in many research laboratories for conducting active neutron interrogation experiments. Requirement of an adequately shielded laboratory is mandatory for the effective and safe utilization of these generators for intended applications. In this reference, we report the comprehensive analysis of shielding effectiveness for High Density Polyethylene (HDPE), Borated Polyethylene (BPE) and Concrete as candidate materials for neutron shielding. In shielding calculations, neutron induced scattering and absorption gamma dose has also been considered along with neutron dose. Contemporarily any material with higher hydrogenous concentration is best suited for neutron shielding. Choice of shielding material is also dominated by practical issues like economic viability and availability of space. Our computational analysis results reveal that utilization of BPE sheets results in minimum wall thickness requirement for attaining similar range of attenuation in neutron and gamma dose. The added advantage of using borated polyethylene is that it reduces the effect of both neutron and gamma dose by absorbing neutron and producing lithium and alpha particle. It has also been realized that for deciding upon optimum thickness determination of any shielding material, three important factors to be necessarily considered are: use factor, occupancy factor and work load factor. (author)

Changes of soft X-ray emission spectra of oxygen and copper in high Tc superconductors

International Nuclear Information System (INIS)

Fukushima, Sei; Gohshi, Yohichi; Kohiki, Shigemi; Saitoh, Naoki

1989-01-01

X-ray induced soft X-ray emission spectroscopy is one of the bulk analysis methods used to characterize high-Tc superconductor. In this report, some observations on the changes in O Kα and Cu L spectra of thin layer LnBa 2 Cu 3 O 7-δ (Ln=Er,Gd) samples are presented. From the measurement of O Kα, no discernible difference was found between those of Gd compounds which were composed single phase or not. It may be said that the electronic structure of p state localized on the O is not sensitive to the change of Tc or zero-resistance temperature. From the measurement of Cu L spectra, it was found that Cu Lα of only Gd containing compounds has a low energy shoulder

Hall effect in high- Tc Y 1Ba 2Cu 3O 7-δ superconductor

Science.gov (United States)

Vezzoli, G. C.; Burke, T.; Moon, B. M.; Lalevic, B.; Safari, A.; Sundar, H. G. K.; Bonometti, R.; Alexander, C.; Rau, C.; Waters, K.

1989-04-01

We have performed point-by-point and continuous Hall effect experiments as a function of temperature in polycrystalline Y 1Ba 2Cu 3O 7-δ. We have shown that the positive Hall constant shows an abrupt increase upon decreasing temperature at a value just above Tc. This temperature corresponds to where the resistance versus temperature data deviates from linearity. At very high fields of 6.8 and 15 T we observe a subsequent decrease in RH. We interpret these data as supportive of a contribution toward the superconductivity mechanism arising from internal excitions or change transfer excitations such that the bound exciton concentration increases near Tc at the expense of positive carries which are reflected in both bound and free holes.

Crossover from three - to two-dimensional behavior of the vortex energies in layered XY-models for high Tc superconductors

International Nuclear Information System (INIS)

Weber, H.; Jensen, H.J.

1992-01-01

We use Monte Carlo simulations of a layered XY-model to study the phase fluctuations in high Tc superconductors. A vortex-antivortex interaction dominated by a term linear in the vortex separation is found in the low temperature regime. This is in agreement with a zero temperature variational calculation. At temperature just above the 2D vortex unbinding temperature the linear term vanishes and an ordinary 2D vortex behaviour is found. This explains the finding that the High Tc superconductors show 2D properties in the vortex fluctuations responsible for the resistivity transition close to the critical temperature. (orig.)

A review of 99mTc labeled myocardial imaging agents for tumor-positive imaging

International Nuclear Information System (INIS)

Xing Shian; Zhang Yongxue; An Rui

2002-01-01

The tumor-positive imaging with high sensitivity and specificity was useful in primary tumor and recurrences and metastases. The 99m Tc labeled myocardial imaging agents are easily available and stable and the radiochemical purity is high. 99m Tc is the preferred choice in routine works because its physical properties. The preparation, quality control, mechanism of accumulation and the clinical use of 99m Tc-sestamibi, 99m Tc-tetrofosmin, 99m Tc-furifosmin, and 99m Tc-N-NOET were reviewed

Use of 99mTc from a commercial 99Mo/9mTc generator as yield tracer for the determination of 99Tc at low levels

DEFF Research Database (Denmark)

Hou, Xiaolin; Jensen, Mikael; Nielsen, Sven Poul

2007-01-01

The concentrations of Tc-99 and impurity radionuclides in the Tc-99m tracer solution obtained from a commercial Mo-99/Tc-99m generator were measured by gamma spectrometry and liquid scintillation counting. Mo-99 and Ru-103 were found in the Tc-99m eluate. A simple separation using two extra alumina...... cartridges was investigated to purify the eluate to obtain a suitable Tc-99m tracer with low Tc-99 concentration. The activity ratio of Tc-99/Tc-99m in the prepared Tc-99m solution is lower than 15 x 10(-9), which is higher than the theoretical ratio of less than 10 x 10(-9). The possible reason is discussed....... The Tc-99 in the 20 kBq spiked Tc-99m tracer was found to be less than 0.3mBq, which is lower than the detection limit of the radiometric method used for environmental samples. The purified Tc-99m eluate is used as yield tracer for the determination of low levels of Tc-99 in environmental samples. (c...

The shielding calculation for the CN guide shielding assembly in HANARO

International Nuclear Information System (INIS)

Kim, H. S.; Lee, B. C.; Lee, K. H.; Kim, H.

2006-01-01

The cold neutron research facility in HANARO is under construction. The area including neutron guides and rotary shutter in the reactor hall should be shielded by the guide shielding assembly which is constructed of heavy concrete blocks and structure. The guide shielding assembly is divided into 2 parts, A and B. Part A is about 6.4 meters apart from the reactor biological shield and it is constructed of heavy concrete blocks whose density is above 4.0g/cm 3 . And part B is a fixed heavy concrete structure whose density is above 3.5g/cm 3 . The rotary shutter is also made with heavy concrete whose density is above 4.0g/cm 3 and includes 5 neutron guides inside. It can block the neutron beam by rotating when CNS is not operating. The dose criterion outside the guide shielding assembly is established as 12.5 μSv/hr which is also applied to reactor shielding in HANARO

Using natural local materials for developing special radiation shielding concretes, and deduction of its shielding characteristics

International Nuclear Information System (INIS)

Kharita, M. H.; Takeyeddin, M.; Al-Nassar, M.; Yousef, S.

2006-06-01

Concrete is considered as the most important material to be used for radiation shielding in facilities contain radioactive sources and radiation generating machines. The concrete shielding properties may vary depending on the construction of the concrete, which is highly relative to the composing aggregates i.e. aggregates consist about 70 - 80% of the total weight of normal concrete. In this project tow types of concrete used in Syria (in Damascus and Aleppo) had been studied and their shielding properties were defined for gamma ray from Cs-137 and Co-60 sources, and for neutrons from Am-Be source. About 10% reduction in HVL was found in the comparison between the tow concrete types for both neutrons and gammas. Some other types of concrete were studied using aggregates from different regions in Syria, to improve the shielding properties of concrete, and another 10% of reduction was achieved in comparison with Damascene concrete (20% in comparison with the concrete from Aleppo) for both neutrons and gamma rays. (author)

Biodistribution of immunoliposome labeled with Tc-99m in tumor xenografted mice

International Nuclear Information System (INIS)

Kitamura, Naoto; Shigematsu, Naoyuki; Nakahara, Tadaki; Kanoh, Momoe; Hashimoto, Jun; Kunieda, Etsuo; Kubo, Atsushi

2009-01-01

Immunoliposome (PEG, GAH, liposome; PGL), consisting of F(ab') 2 fragment of monoclonal antibody, GAH and polyethyleneglycol-coated (PEGylated) liposome was provided. Immunoliposome, PGL was labeled with technetium-99m (Tc-99m) by two methods: labeling F(ab') 2 fragment with Tc-99m; Tc-99m-PGL, and entrapping Tc-99m into liposome; PGL[Tc-99m]. The objective of this study was to compare the biodistribution of Tc-99m-PGL and PGL[Tc-99m] in human gastric cancer xenografted mice. Tc-99m-PGL, PGL[Tc-99m], and Tc-99m-entrapped liposome; Lipo[Tc-99m] were prepared. They were injected into human gastric cancer, MKN45, xenografted mice via the tail vein, and their biodistribution was studied. No marked accumulation of either PGL[Tc-99m] or Lipo[Tc-99m] was observed in the stomach. The uptake of Tc-99m-PGL by the liver, spleen, and lung was higher than that by the tumor. On the other hand, the uptake of PGL[Tc-99m] by the lung and spleen was markedly lower as compared with that of Tc-99m-PGL; the accumulation of PGL[Tc-99m] was lower in the lung and higher in the spleen as compared with that of the tumor. Although the liver uptake of PGL[Tc-99m] was markedly decreased as compared with that of Tc-99m-PGL, it was higher than the uptake of the tumor. The Tc-99m-PGL was strongly taken up by the tumor, with a high level of incorporation also seen in the stomach. These findings suggest the need for further study of the labeling stability. PGL[Tc-99m] appears to show promise for high tumor uptake and retention. This is an important implication for the potential application of immunoliposomes entrapped with Re-186, instead of Tc-99m, in internal radiotherapy. (author)

Impeding 99Tc(IV) mobility in novel waste forms

Science.gov (United States)

Lee, Mal-Soon; Um, Wooyong; Wang, Guohui; Kruger, Albert A.; Lukens, Wayne W.; Rousseau, Roger; Glezakou, Vassiliki-Alexandra

2016-01-01

Technetium (99Tc) is an abundant, long-lived radioactive fission product whose mobility in the subsurface is largely governed by its oxidation state. Tc immobilization is crucial for radioactive waste management and environmental remediation. Tc(IV) incorporation in spinels has been proposed as a novel method to increase Tc retention in glass waste forms during vitrification. However, experiments under high-temperature and oxic conditions show reoxidation of Tc(IV) to volatile pertechnetate, Tc(VII). Here we examine this problem with ab initio molecular dynamics simulations and propose that, at elevated temperatures, doping with first row transition metal can significantly enhance Tc retention in magnetite in the order Co>Zn>Ni. Experiments with doped spinels at 700 °C provide quantitative confirmation of the theoretical predictions in the same order. This work highlights the power of modern, state-of-the-art simulations to provide essential insights and generate theory-inspired design criteria of complex materials at elevated temperatures. PMID:27357121

Simulation of photon attenuation coefficients for high effective shielding material Lead-Boron Polyethyene

Science.gov (United States)

Zhang, L.; Jia, M. C.; Gong, J. J.; Xia, W. M.

2017-12-01

The mass attenuation coefficient of various Lead-Boron Polyethylene samples which can be used as the photon shielding materials in marine reactor, have been simulated using the MCNP-5 code, and compared with the theoretical values at the photon energy range 0.001MeV—20MeV. A good agreement has been observed. The variations of mass attenuation coefficient, linear attenuation coefficient and mean free path with photon energy between 0.001MeV to 100MeV have been plotted. The result shows that all the coefficients strongly depends on the photon energy, material atomic composition and density. The dose transmission factors for source Cesium-137 and Cobalt-60 have been worked out and their variations with the thickness of various sample materials have also been plotted. The variations show that with the increase of materials thickness the dose transmission factors decrease continuously. The results of this paper can provide some reference for the use of the high effective shielding material Lead-Boron Polyethyene.

Neutron shielding material

International Nuclear Information System (INIS)

Suzuki, Shigenori; Iimori, Hiroshi; Kobori, Junzo.

1980-01-01

Purpose: To provide a neutron shielding material which incorporates preferable shielding capacity, heat resistance, fire resistance and workability by employing a mixture of thermosetting resin, polyethylene and aluminium hydroxide in special range ratio and curing it. Constitution: A mixture containing 20 to 60% by weight of thermosetting resin having preferable heat resistance, 10 to 40% by weight of polyethylene powder having high hydrogen atom density and 1000 to 60000 of molecular weight, and 15 to 55% by weight of Al(OH) 3 for imparting fire resistance and self-fire extinguishing property thereto is cured. At this time approx. 0.5 to 5% of curing catalyst of the thermosetting resin is contained in 100 parts by weight of the mixture. (Sekiya, K.)

INTOR radiation shielding for personnel access

International Nuclear Information System (INIS)

Gohar, Y.; Abdou, M.

1981-01-01

The INTOR reactor shield system consists of the blanket, bulk shield, penetration shield, component shield, and biological shield. The bulk shield consists of two parts: (a) the inboard shield; and (b) the outboard shield. The distinction between the different components of the shield system is essential to satisfy the different design constraints and achieve various objectives

Neutron shield analysis and design for the PDX fusion facility

International Nuclear Information System (INIS)

Grimesey, R.A.; Nigg, D.W.; Scott, A.J.; Wheeler, F.J.; Jassby, D.L.; Perry, E.D.

1979-01-01

The basic component of the biological shield for PDX is an existing 81 cm thick high-density concrete shielding wall surrounding the machine. The principal additional shielding requirement is a roof shield over the machine to reduce air-scattered skyshine dose into the PDX control room and to the site boundary. The roof shield is designed in removable sections on a steel support structure permitting overhead crane access to major PDX components. After analysis of a number of alternate concepts, a roof shield consisting of 50 cm of water in polyethylene tanks was selected to meet design objectives of effectiveness, weight, removability, and cost

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.

Evaluation of the absorbed dose to the kidneys due to Tc99m (DTPA) / Tc99m (Mag3) and Tc99m (Dmsa)

International Nuclear Information System (INIS)

Vasquez A, M.; Murillo C, F.; Castillo D, C.; Rocha J, J.; Sifuentes D, Y.; Sanchez S, P.; Idrogo C, J.; Marquez P, F.

2015-10-01

The absorbed dose in the kidneys of adult patients has been assessed using the biokinetics of radiopharmaceuticals containing Tc 99m (DTPA) / Tc 99m (Mag3) or Tc 99m (Dmsa).The absorbed dose was calculated using the formalism MIRD and the Cristy-Eckerman representation for the kidneys. The absorbed dose to the kidneys due to Tc 99m (DTPA) / Tc 99m (Mag3), are given by 0.00466 mGy.MBq -1 / 0.00339 mGy.MBq -1 . Approximately 21.2% of the absorbed dose is due to the bladder (content) and the remaining tissue, included in biokinetics of Tc 99m (DTPA) / Tc 99m (Mag3). The absorbed dose to the kidneys due to Tc 99m (Dmsa) is 0.17881 mGy.MBq -1 . Here, 1.7% of the absorbed dose is due to the bladder, spleen, liver and the remaining tissue, included in biokinetics of Tc 99m (Dmsa). (Author)

99mTc-Alafosfalin: an antibiotic peptide infection imaging agent

International Nuclear Information System (INIS)

Tsopelas, C.; Penglis, S.; Ruszkiewicz, A.; Bartholomeusz, F.D.L.

2003-01-01

The radiolabeled antibiotic peptide 99m Tc-alafosfalin was assessed as an infection imaging agent in a rat model by comparison with 99m Tc-DTPA and 99m Tc-leukocytes. 99m Tc-alafosfalin was prepared via an instant cold kit and 99m Tc-leukocytes were prepared using 99m Tc-stannous fluoride colloid in an ex vivo labeling procedure of whole blood. In separate experiments, the three radiotracers were administered to rats infected with staphylococcus aureus. Quantitative biodistribution studies were performed as well as scintigraphic images and histopathology. 99m Tc-alafosfalin is a stable product, obtained in high radiochemical purity (>95%). This agent was mainly renally excreted, with low liver, spleen and bone uptake, and resulted in a mean ratio of infected/non-infected thighs of 4.3/1.0 at 4 hr post radiotracer injection. 99m Tc-DTPA gave a corresponding ratio of 1.9/1.0 and 99m Tc-leukocytes gave 20.0/1.0 at the same time point. An in vitro assay found the level of 99m Tc-alafosfalin binding to staphylococcus aureas higher than 99m Tc-DTPA (10% versus 1% respectively). 99m Tc-alafosfalin accumulates at sites of infection in a rat model better than the perfusion molecule 99m Tc-DTPA, yet less than 99m Tc-leukocytes. The distribution characteristics of this 99m Tc-antibiotic peptide would be an advantage in imaging abdominal and soft tissue infection

Neutron shieldings

International Nuclear Information System (INIS)

Tarutani, Kohei

1979-01-01

Purpose: To decrease the stresses resulted by the core bendings to the base of an entrance nozzle. Constitution: Three types of round shielding rods of different diameter are arranged in a hexagonal tube. The hexagonal tube is provided with several spacer pads receiving the loads from the core constrain mechanism at its outer circumference, a handling head for a fuel exchanger at its top and an entrance nozzle for self-holding the neutron shieldings and flowing heat-removing coolants at its bottom. The diameters for R 1 , R 2 and R 3 for the round shielding rods are designed as: 0.1 R 1 2 1 and 0.2 R 1 2 1 . Since a plurality of shielding rods of small diameter are provided, soft structure are obtained and a plurality of coolant paths are formed. (Furukawa, Y.)

Repository Waste Package Transporter Shielding Weight Optimization

International Nuclear Information System (INIS)

C.E. Sanders; Shiaw-Der Su

2005-01-01

The Yucca Mountain repository requires the use of a waste package (WP) transporter to transport a WP from a process facility on the surface to the subsurface for underground emplacement. The transporter is a part of the waste emplacement transport systems, which includes a primary locomotive at the front end and a secondary locomotive at the rear end. The overall system with a WP on board weights over 350 metric tons (MT). With the shielding mass constituting approximately one-third of the total system weight, shielding optimization for minimal weight will benefit the overall transport system with reduced axle requirements and improved maneuverability. With a high contact dose rate on the WP external surface and minimal personnel shielding afforded by the WP, the transporter provides radiation shielding to workers during waste emplacement and retrieval operations. This paper presents the design approach and optimization method used in achieving a shielding configuration with minimal weight

Tungsten-based composite materials for fusion reactor shields

International Nuclear Information System (INIS)

Greenspan, E.; Karni, Y.

1985-01-01

Composite tungsten-based materials were recently proposed for the heavy constituent of compact fusion reactor shields. These composite materials will enable the incorporation of tungsten - the most efficient nonfissionable inelastic scattering (as well as good neutron absorbing and very good photon attenuating) material - in the shield in a relatively cheap way and without introducing voids (so as to enable minimizing the shield thickness). It is proposed that these goals be achieved by bonding tungsten powder, which is significantly cheaper than high-density tungsten, with a material having the following properties: good shielding ability and relatively low cost and ease of fabrication. The purpose of this work is to study the effectiveness of the composite materials as a function of their composition, and to estimate the economic benefit that might be gained by the use of these materials. Two materials are being considered for the binder: copper, second to tungsten in its shielding ability, and iron (or stainless steel), the common fusion reactor shield heavy constituent

Equipment and detectors calibration behind shielding of CERN high-energy particle accelerator SPS: June 2007

International Nuclear Information System (INIS)

Spurny, Frantisek; Ploc, Ondrej

2008-02-01

High energy stray radiation fields have been realised since 1993 at CERN also in the frame of CEC-CERN collaboration on the project: 'Detection and the Dosimetry of Neutrons and Charged Particles at Aviation Altitudes in the Earth's Atmosphere'. They are formed at the H6 beam of the north experimental area of the SPS facility. Two shielding configurations have been built, with the top concrete, resp. top iron shielding. Many intercalibration experiments have been realised since the beginning. After an interruption due to technical problems, two other campaigns have been realised during 2006 year, another one during the June 2007. This report describes analyses and discusses the most of results obtained during the last, 2007 run.. (author)

High-Tc Superconductors Based on FeAs Compounds

CERN Document Server

Izyumov, Yuri

2010-01-01

Physical properties and models of electronic structure are analyzed for a new class of high-TC superconductors which belong to iron-based layered compounds. Despite their variable chemical composition and differences in the crystal structure, these compounds possess similar physical characteristics, due to electron carriers in the FeAs layers and the interaction of these carriers with fluctuations of the magnetic order. A tremendous interest towards these materials is explained by the prospects of their practical use. In this monograph, a full picture of the formation of physical properties of these materials, in the context of existing theory models and electron structure studies, is given. The book is aimed at a broad circle of readers: physicists who study electronic properties of the FeAs compounds, chemists who synthesize them and specialists in the field of electronic structure calculations in solids. It is helpful not only to researchers active in the fields of superconductivity and magnetism, but also...

Engineering design of the IFMIF EVEDA reference test cell and key components

Energy Technology Data Exchange (ETDEWEB)

Tian, Kuo, E-mail: kuo.tian@kit.edu [Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology, Karlsruhe (Germany); Arbeiter, Frederik; Chen, Yuming; Heinzel, Volker; Kondo, Keitaro [Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology, Karlsruhe (Germany); Mittwollen, Martin [Institute for Material Handling and Logistics, Karlsruhe Institute of Technology, Karlsruhe (Germany)

2014-10-15

The latest design updates of the IFMIF-EVEDA reference test cell (TC) are described with emphasis on the following key components: active cooling pipes for concrete biological shielding walls and stainless steel liner, TC gas leak tight boundary, and piping and cabling inside TC and between TC and the access cell (AC). Water cooling is adopted for concrete shielding walls and the liner. Buried pipes are selected for active cooling of the TC surrounding shielding walls; directly welded pipes on the liner are used to remove nuclear heat of the liner. Technical features and layout of the cooling pipes are preliminary defined. The TC vacuum boundary, which includes the TC liner, an independent TC cover plate, a rubber based sealing gasket, and welding seams between interface shielding plugs and TC liner, is described. Engineering design of the piping and cabling plugs as well as the arrangement of pipes and cables under the TC covering plate and the AC floor are updated. Pipes and cable tunnels inside the shielding plugs are arranged with several bends for minimizing neutron streaming from inside to outside of the TC. Pipes, cables, and the corresponding penetrations between the TC and the AC are carefully arranged for convenient access and maintenances.

Availability of 99Tc in undisturbed soil cores

International Nuclear Information System (INIS)

Denys, Sebastien; Echevarria, Guillaume; Florentin, Louis; Leclerc-Cessac, Elisabeth; Morel, Jean-Louis

2003-01-01

Models for safety assessment of radioactive waste repositories need accurate values of the soil-to-plant transfer of radionuclides. In oxidizing environments, 99 Tc is expected to occur as pertechnetate ( 99 TcO 4 - ). Due to its high mobility, leaching of this element in the field might be important, potentially affecting the reliability of estimated transfer parameters of 99 Tc as measured in closed experimental systems such as hydroponics or pot experiments. The aim of this experiment was to measure the leaching of 99 Tc in undisturbed irrigated soil cores under cultivation as well as plant uptake and to study the possible competition between the two transfer pathways. Undisturbed soil cores (50x50 cm) were sampled from a Rendzic Leptosol (R), a colluvial Fluvic Cambisol (F) and a Dystric Cambisol (D) using PVC tubes (three cores sampled per soil type). Each core was equipped with a leachate collector at the bottom, allowing the monitoring of 99 Tc leaching through the cores. Cores were placed in a greenhouse and maize (Zea mays L., cv. DEA, Pioneer[reg]) was sown. After 135 d, maize was harvested and radioactivity determined in both plant and water samples. Results showed that during the growing period, leaching of 99 Tc was limited, due to the high evapotranspiration rate of maize. After harvest, leaching of 99 Tc went on because of the absence of evapotranspiration. Effective uptake (EU) of 99 Tc in leaves and grains was calculated. EU reached 70% of the input in the leaves and was not significantly different among soils. These results confirmed those obtained from pot experiments, even though leaching was allowed to occur in close-to-reality hydraulical conditions. As a consequence, it was concluded that pot experiments are an adequate surrogate for more complex 'close-to-reality' experimental systems for measuring transfer factors

Thermal neutron shield and method of manufacture

Science.gov (United States)

Brindza, Paul Daniel; Metzger, Bert Clayton

2013-05-28

A thermal neutron shield comprising concrete with a high percentage of the element Boron. The concrete is least 54% Boron by weight which maximizes the effectiveness of the shielding against thermal neutrons. The accompanying method discloses the manufacture of Boron loaded concrete which includes enriching the concrete mixture with varying grit sizes of Boron Carbide.

Preparation and bioevaluation of 99mTc-carbonyl complex of guanine

International Nuclear Information System (INIS)

Cigdem Ichedef; Serap Teksoez; Kamile Senocak; Eser Ucar; Ayfer Yurt Kilcar

2011-01-01

The aim of this study is to prepare radiolabeled guanine with 99m Tc(CO) 3 + core. For this purpose, guanine has been radiolabeled with 99m Tc(CO) 3 + core. Quality control study of radiolabeled guanine molecule with 99m Tc(CO) 3 + core was performed by thin layer radio chromatography (TLRC) and high performance liquid radio chromatography (HPLRC). The results showed that the radiolabeling yield was quite high (94 ± 3%). Beside that 99m Tc(CO) 3 -Gua complex has showed good in vitro stability during the 24 h period. Radiopharmaceutical potential of this complex was evaluated in Wistar Albino Rats. It was concluded that 99m Tc(CO) 3 -Gua could be used as a nucleotide radiopharmaceutical for in vivo applications. (author)

Measurement of TFTR D-T radiation shielding efficiency

International Nuclear Information System (INIS)

Kugel, H.W.; Ascione G.; Elwood, S.

1994-01-01

High power D-T fusion reactor designs presently exhibit complex geometric and material density configurations. Simulations of the radiation shielding required for safe operation and full compliance with all regulatory requirements must include sufficient margin to accommodate uncertainties in material properties and distributions, uncertainties in the final configurations, and uncertainties in approximations employing the homogenization of complex geometries. Measurements of radiation shielding efficiency performed in a realistic D-T tokamak environment can provide empirical guidance for simulating safe, efficient, and cost effective shielding systems for future high power fusion reactors. In this work, the authors present the results of initial measurements of the TFTR radiation shielding efficiency during high power D-T operations with record neutron yields. The TFTR design objective is to limit the total dose-equivalent at the nearest PPPL property lines from all radiation pathways to 10 mrem per calendar year. Compliance with this design objective over a calendar year requires measurements in the presence of typical site backgrounds of about 80 mrem per year

Tc-99m Glu-Cys-Gly-His-Gly-Lys (ECG-HGK), a novel Tc-99m labeled hexapeptide for molecular tumor imaging.

Science.gov (United States)

Kim, Dae-Weung; Kim, Myoung Hyoun; Kim, Chang Guhn

2016-03-01

Domain 5 of kinin-free high molecular weight kininogen inhibits the adhesion of many tumor cell lines, and it has been reported that the histidine-glycine-lysine (HGK)-rich region might be responsible for inhibition of cell adhesion. The authors developed HGK-containing hexapeptide, glutamic acid-cysteine-glycine (ECG)-HGK, and evaluated the utility of Tc-99m ECG-HGK for tumor imaging. Hexapeptide, ECG-HGK was synthesized using Fmoc solid-phase peptide synthesis. Radiolabeling efficiency was evaluated. The uptake of Tc-99m ECG-HGK within HT-1080 cells was evaluated in vitro. In HT-1080 tumor-bearing mice, gamma imaging and biodistribution studies were performed. The complexes Tc-99m ECG-HGK was prepared in high yield. The uptake of Tc-99m ECG-HGK within the HT-1080 tumor cells had been demonstrated by in vitro studies. The gamma camera imaging in the murine model showed that Tc-99m ECG-HGK was accumulated substantially in the HT-1080 tumor (tumor-to-muscle ratio = 5.7 ± 1.4 at 4 h), and the tumoral uptake was blocked by the co-injection of excess HGK (tumor-to-muscle ratio = 2.8 ± 0.6 at 4 h). In the present study, Tc-99m ECG-HGK was developed as a new tumor imaging agents. Our in vitro and in vivo studies revealed specific function of Tc-99m ECG-HGK for tumor imaging. Copyright © 2016 John Wiley & Sons, Ltd.

Electrical Insulation of 500-m High-Tc Superconducting Power Cable

International Nuclear Information System (INIS)

Takahashi, T; Ichikawa, M; Suzuki, H; Okamoto, T; Akita, S; Mukoyama, S; Yagi, M; Maruyama, S; Kimura, A

2006-01-01

Electrical insulation is one of the essential technologies for the electric power apparatus. Determination of testing voltages and design method of the electrical insulation layer are inextricably linked each other, and are critical to developing and realizing a cold dielectric (CD) type high-Tc superconducting (HTS) power cable. The authors had proposed the electrical insulation design method with concepts of partial discharge-free designs for ac voltage condition. This paper discusses the testing voltages for a 77 kV 1000 A HTS power cable with a length of 500 m, and describes results of various voltage withstand test. As a result, it is concluded that the proposed electrical insulation design method is appropriate for the HTS power cable

Innovative technologies for Faraday shield cooling

International Nuclear Information System (INIS)

Rosenfeld, J.H.; Lindemuth, J.E.; North, M.T.; Goulding, R.H.

1995-01-01

Alternative advanced technologies are being evaluated for use in cooling the Faraday shields used for protection of ion cyclotron range of frequencies (ICR) antennae in Tokamaks. Two approaches currently under evaluation include heat pipe cooling and gas cooling. A Monel/water heat pipe cooled Faraday shield has been successfully demonstrated. Heat pipe cooling offers the advantage of reducing the amount of water discharged into the Tokamak in the event of a tube weld failure. The device was recently tested on an antenna at Oak Ridge National Laboratory. The heat pipe design uses inclined water heat pipes with warm water condensers located outside of the plasma chamber. This approach can passively remove absorbed heat fluxes in excess of 200 W/cm 2 ;. Helium-cooled Faraday shields are also being evaluated. This approach offers the advantage of no liquid discharge into the Tokamak in the event of a tube failure. Innovative internal cooling structures based on porous metal cooling are being used to develop a helium-cooled Faraday shield structure. This approach can dissipate the high heat fluxes typical of Faraday shield applications while minimizing the required helium blower power. Preliminary analysis shows that nominal helium flow and pressure drop can sufficiently cool a Faraday shield in typical applications. Plans are in progress to fabricate and test prototype hardware based on this approach

An effective 2-band eg model of sulfur hydride H3S for high-Tc superconductivity

Science.gov (United States)

Nishiguchi, Kazutaka; Teranishi, Shingo; Miyao, Satoaki; Matsushita, Goh; Kusakabe, Koichi

To understand high transition temperature (Tc) superconductivity in sulfur hydride H3S, we propose an effective 2-band model having the eg symmetry as the minimal model for H3S. Two eg orbitals centered on a sulfur S atom are chosen for the smallest representation of relevant bands with the van-Hove singularity around the Fermi levels except for the Γ-centered small hole pockets by the sulfur 3 p orbitals. By using the maximally localized Wannier functions, we derive the minimal effective model preserving the body-centered cubic (bcc) crystal symmetry of the H3S phase having the highest Tc ( 203 K under pressures) among the other polymorphs of H3S.

Synthesis, radiochromatography and biodistribution of sup(99m)Tc-dimethylphosphinoethane (DMPE) complexes

International Nuclear Information System (INIS)

Angelberger, P.; Wagner-Loeffler, M.; Hruby, E.; Dudczak, R.

1985-01-01

The title complex were prepared from no-carrier-added sup(99m)Tc-TcOsub(4)sup(-) and the air-sensitive reducing ligand DMPE under argon in ethanol-water. At acidic pH [Tc(III)Clsub(2) dmpesub(2)]sup(+) was formed, while alkaline pH led to the formation of 95% yield in less than 1 hour, otherwise the [Tc(V)Osub(2)dmpesub(2)]sup(+) intermediate was present. Electrophoresis demonstrated the unit positive charge and reversed-phase ion-pair HPLC provided separation and identification of sup(99m)Tc-products by direct comparison with known sup(99m)Tc-complexes. In rats the sup(99m)Tc-complexes were excrated by kidneys and liver and reached high heart/blood but only low heart/lung and heart/liver ratios. In dogs satisfactory myocardial scintigrams were obtained in spite of high liver activity. (author)

Slipforming of reinforced concrete shield building

International Nuclear Information System (INIS)

Hsieh, M.C.; King, J.R.

1982-01-01

The unique design and construction features of slipforming the heavily reinforced concrete cylindrical shield walls at the Satsop nuclear plant in Washington, D.C. site are presented. The shield walls were designed in compliance with seismic requirements which resulted in the need for reinforcing steel averaging 326 kg/m/sup 3/. A 7.6 m high, three-deck moving platform was designed to permit easy installation of the reinforcing steel, embedments, and blockouts, and to facilitate concrete placement and finishing. Two circular box trusses, one on each side of the shield wall, were used in combination with a spider truss to meet both the tolerance and strength requirements for the slipform assembly

Radiation shielding plate

International Nuclear Information System (INIS)

Kobayashi, Torakichi; Sugawara, Takeo.

1983-01-01

Purpose: To reduce the weight and stabilize the configuration of a radiation shielding plate which is used in close contact with an object to be irradiated with radiation rays. Constitution: The radiation shielding plate comprises a substrate made of lead glass and a metallic lead coating on the surface of the substrate by means of plating, vapor deposition or the like. Apertures for permeating radiation rays are formed to the radiation shielding plate. Since the shielding plate is based on a lead glass plate, a sufficient mechanical strength can be obtained with a thinner structure as compared with the conventional plate made of metallic lead. Accordingly, if the shielding plate is disposed on a soft object to be irradiated with radiation rays, the object and the plate itself less deform to obtain a radiation irradiation pattern with distinct edges. (Moriyama, K.)

The development and characterization of Tc-99m mecaptoacetyltriglycine (MAG3)

International Nuclear Information System (INIS)

Taylor, A. Jr.; Eshima, D.

1990-01-01

I-131 orth-iodohippuric (OIH) acid is a widely used renal radiopharmaceutical but it is limited due to the suboptimal imaging properties of the I-131 radionuclide and the relatively high radiation dose. Recent work has focused on the development of Tc-99m renal tubular function agents which would utilize the optimal radionuclidic properties and availability of Tc-99m, provide comparable clinical information to that obtained with OIH and allow the evaluation of renal perfusion. The triamide mercaptide (N 3 S) donor ligand system has yielded the most promising Tc-99m tubular function agent to date. Tc-99m mercaptoacetyltriglycine MAG 3 does not enter the red blood cell. A simple kit formulation has been developed which yields a stable Tc-99m MAG 3 complex in high radiochemical purity. Studies in normal volunteers and patients indicate that Tc-99m MAG 3 is an excellent Tc-99m renal tubular agent but its clearance is only 50-60% that of OIH. 42 refs., 2 tabs., 2 figs

Experimental and analytical study for demonstration program on shielding of casks for high-level wastes

International Nuclear Information System (INIS)

Ueki, K.; Nakazawa, M.; Hattorl, S.; Ozaki, S.; Tamaki, H.; Kadotani, H.; Ishizuka, T.; Ishikawa, S.

1993-01-01

The following remarks were obtained from the experiment and the DOT 3.5 and the MCNP analyses on the gamma ray and the neutron dose equivalent rates in the cask of interest. 1. The cask has thinner neutron shielding parts around the trunnions. Significant neutrons streaming around the trunnion parts was observed which was also cleared by the MCNP analysis for the 252 Cf source experiment. Accordingly, detailed neutron streaming calculations are required to evaluate the dose levels around the trunnions when loading the vitrified high-level wastes. 2. The room-scattered obstructive neutrons, mainly originating from the neutrons penetrating around the trunnions, at the top and the bottom of the cask are reduced significantly by preparing the water tank at the top and the water layer at the bottom. Therefore, a more accurate experiment is to be carried out in the future shielding experiment especially for neutrons. However, because the water tank and the layer do not exist in the actual high-level wastes transport cask, the experiment without the water tank and layer are not dispensable to demonstrate the transport conditions of the actual cask, too. 3. The gamma-ray and the neutron dose equivalent rate distributions obtained from the DOT 3.5 and the MCNP calculations, respectively, agreed closely with the measured values in the cask areas of interest. Accordingly, the DOT 3.5 code and the MCNP code with the NESX estimator can be employed not only for the shielding analysis of the future experiments, but also for making a safety analysis report of high-level wastes transport casks. (J.P.N.)

Electromagnetic shield

International Nuclear Information System (INIS)

Miller, J.S.

1987-01-01

An electromagnetic shield is described comprising: closed, electrically-conductive rings, each having an open center; and binder means for arranging the rings in a predetermined, fixed relationship relative to each other, the so-arranged rings and binder means defining an outer surface; wherein electromagnetic energy received by the shield from a source adjacent its outer surface induces an electrical current to flow in a predetermined direction adjacent and parallel to the outer surface, through the rings; and wherein each ring is configured to cause source-induced alternating current flowing through the portion of the ring closest to the outer surface to electromagnetically induce an oppositely-directed current in the portion of the ring furthest from the surface, such oppositely-directed current bucking any source-induced current in the latter ring portion and thus reducing the magnitude of current flowing through it, whereby the electromagnetic shielding effected by the shield is enhanced