Sub-barrier fusion: An experimental review

International Nuclear Information System (INIS)

Betts, R.R.

1991-01-01

This paper contains a review of the current status of the experimental study of heavy-ion fusion at sub-barrier energies. Emphasis is placed on the comparison of the experimentally observed quantities with theoretical expectations. Results of measurements of the spin distributions of the composite systems formed following fusion are critically examined with a view to understanding the large discrepancies between theory and experiment which exist for some systems. 20 refs., 14 figs

Frontiers in propulsion research: Laser, matter-antimatter, excited helium, energy exchange thermonuclear fusion

Science.gov (United States)

Papailiou, D. D. (Editor)

1975-01-01

Concepts are described that presently appear to have the potential for propulsion applications in the post-1990 era of space technology. The studies are still in progress, and only the current status of investigation is presented. The topics for possible propulsion application are lasers, nuclear fusion, matter-antimatter annihilation, electronically excited helium, energy exchange through the interaction of various fields, laser propagation, and thermonuclear fusion technology.

Measurement of fusion excitation functions in the system {sup 78}Kr + {sup 100}Mo

Energy Technology Data Exchange (ETDEWEB)

Rehm, K.E.; Jiang, C.L.; Esbensen, H. [and others

1995-08-01

Earlier measurements of fusion reactions involving {sup 78}Kr and {sup 100}Mo projectiles and Ni-targets showed surprisingly large fusion yields at low energies which could not be explained by coupled-channels calculations. The main difference to similar measurements involving the neighboring {sup 86}Kr and {sup 92}Mo isotopes was the different slope of the excitation functions at sub-barrier energies. An analysis of a variety of experiments showed a correlation between the nuclear structure and the slope of the excitation functions, with the {open_quotes}soft{close_quotes} transitional nuclei ({sup 78}Kr, {sup 100}Mo) exhibiting shallower slopes than the {open_quotes}stiff{close_quotes} nuclei ({sup 86}Kr, {sup 92}Mo) measured at the same energies with respect to the barrier. In this experiment we studied the fusion excitation function involving two transitional nuclei {sup 78}Kr + {sup 100}Mo. The measurements were performed with {sup 78}Kr beams from the ECR source at energies between 285-370 MeV. Separation of the evaporation nucleus from the elastically scattered particles was achieved by measuring time-of-flight and magnetic rigidity in the gas-filled spectrograph. The data were completely analyzed. A comparison of the cross sections with measurements for the system {sup 86}Kr + {sup 92}Mo populating the same compound nucleus {sup 178}Pt. It shows good agreement at the highest energies, but quite different falloffs of the excitation functions toward lower energies. Coupled-channels calculations, including multi-phonon excitation for the two systems, are being performed.

Calculations of Excitation Functions of Some Structural Fusion Materials for ( n, t) Reactions up to 50 MeV Energy

Science.gov (United States)

Tel, E.; Durgu, C.; Aktı, N. N.; Okuducu, Ş.

2010-06-01

Fusion serves an inexhaustible energy for humankind. Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. Tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So, the working out the systematics of ( n, t) reaction cross sections is of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at different energies. In this study, ( n, t) reactions for some structural fusion materials such as 27Al, 51V, 52Cr, 55Mn, and 56Fe have been investigated. The new calculations on the excitation functions of 27Al( n, t)25Mg, 51V( n, t)49Ti, 52Cr( n, t)50V, 55Mn( n, t)53Cr and 56Fe( n, t)54Mn reactions have been carried out up to 50 MeV incident neutron energy. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the new evaluated the geometry dependent hybrid model, hybrid model and the cascade exciton model. Equilibrium effects are calculated according to the Weisskopf-Ewing model. Also in the present work, we have calculated ( n, t) reaction cross-sections by using new evaluated semi-empirical formulas developed by Tel et al. at 14-15 MeV energy. The calculated results are discussed and compared with the experimental data taken from the literature.

Design activities of a fusion experimental breeder

International Nuclear Information System (INIS)

Huang, J.; Feng, K.; Sheng, G.

1999-01-01

The fusion reactor design studies in China are under the support of a fusion-fission hybrid reactor research Program. The purpose of this program is to explore the potential near-term application of fusion energy to support the long-term fusion energy on the one hand and the fission energy development on the other. During 1992-1996 a detailed consistent and integral conceptual design of a Fusion Experimental Breeder, FEB was completed. Beginning from 1996, a further design study towards an Engineering Outline Design of the FEB, FEB-E, has started. The design activities are briefly given. (author)

Design activities of a fusion experimental breeder

International Nuclear Information System (INIS)

Huang, J.; Feng, K.; Sheng, G.

2001-01-01

The fusion reactor design studies in China are under the support of a fusion-fission hybrid reactor research Program. The purpose of this program is to explore the potential near-term application of fusion energy to support the long-term fusion energy on the one hand and the fission energy development on the other. During 1992-1996 a detailed consistent and integral conceptual design of a Fusion Experimental Breeder, FEB was completed. Beginning from 1996, a further design study towards an Engineering Outline Design of the FEB, FEB-E, has started. The design activities are briefly given. (author)

Management of Waste from the Fusion Experimental Breeder

Institute of Scientific and Technical Information of China (English)

1998-01-01

<正> Fusion breeder might be an essential intermediate application of fusion energy at earlier term, which has the potential to provide plenty of commercial fissile fuel. Based on fusion physics and technologies available at present and in near future, the realistic Fusion Experimental Breeder, FEB-E was designed. The obiectives of the FEB-E are to demonstrate the engineering feasibility of

Evaluation of Complete Fusion Excitation Functions for 42≤ZpZT≤2000

International Nuclear Information System (INIS)

Al-Haydari, A.; Abdelghany, A.A.; Hassan, G. S.

2011-01-01

For fusion channels, there are two main parameters, namely the separating distance of the two colliding nuclei and the fusion barrier, which are aken as the more interest points guiding to fit the excitation functions of fusion. Interpretations and differentiations are made on different forms to deduce all concerned variables. On the other hand, the maximum values of angular momentum 1 m ax , represents the upper limit of summing all the partial parts for fusion cross section The effect of that limiting value as well as the effects of the two main parameters are checked along iwde range of energies for different heavy ion reacting pairs in comparison with the more recently measured data for sub-barrier and complete fusion channels . Also comparisons with both 1 f us and 1 c r, taken as limiting values were displayed. The effect of the nuclear part of the barrier height and approximation techniques have been checked point out the highly differentiated ones .parameterization that could be made on the imperical forms, are also displayed and tested.

Fusion enhancement at near and sub-barrier energies in {sup 19}O + {sup 12}C

Energy Technology Data Exchange (ETDEWEB)

Singh, Varinderjit; Vadas, J.; Steinbach, T.K.; Wiggins, B.B.; Hudan, S. [Department of Chemistry and Center for Exploration of Energy and Matter, Indiana University, 2401 Milo B. Sampson Lane, Bloomington, IN 47408 (United States); Souza, R.T. de, E-mail: deSouza@indiana.edu [Department of Chemistry and Center for Exploration of Energy and Matter, Indiana University, 2401 Milo B. Sampson Lane, Bloomington, IN 47408 (United States); Lin, Zidu; Horowitz, C.J. [Department of Physics and Center for Exploration of Energy and Matter, Indiana University, 2401 Milo B. Sampson Lane, Bloomington, IN 47408 (United States); Baby, L.T.; Kuvin, S.A.; Tripathi, Vandana; Wiedenhöver, I. [Department of Physics, Florida State University, Tallahassee, FL 32306 (United States); Umar, A.S. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States)

2017-02-10

Measuring the fusion excitation function for an isotopic chain of projectile nuclei provides a stringent test of a microscopic description of fusion. We report the first measurement of the fusion excitation function at near-barrier energies for the {sup 19}O + {sup 12}C system. The measured excitation function is compared with the fusion excitation function of {sup 18}O + {sup 12}C. A significant enhancement in the fusion probability of {sup 19}O ions with a {sup 12}C target as compared to {sup 18}O ions is observed. The experimental cross-sections observed at near-barrier energies are compared with a state-of-the-art microscopic model.

Collection of experimental data for fusion neutronics benchmark

International Nuclear Information System (INIS)

Maekawa, Fujio; Yamamoto, Junji; Ichihara, Chihiro; Ueki, Kotaro; Ikeda, Yujiro.

1994-02-01

During the recent ten years or more, many benchmark experiments for fusion neutronics have been carried out at two principal D-T neutron sources, FNS at JAERI and OKTAVIAN at Osaka University, and precious experimental data have been accumulated. Under an activity of Fusion Reactor Physics Subcommittee of Reactor Physics Committee, these experimental data are compiled in this report. (author)

Hot nuclei, limiting temperatures and excitation energies

International Nuclear Information System (INIS)

Peter, J.

1986-09-01

Hot fusion nuclei are produced in heavy ion collisions at intermediate energies (20-100 MeV/U). Information on the maximum excitation energy per nucleon -and temperatures- indicated by the experimental data is compared to the predictions of static and dynamical calculations. Temperatures around 5-6 MeV are reached and seem to be the limit of formation of thermally equilibrated fusion nuclei

Experimental studies of processes with vibrationally excited hydrogen molecules that are important for tokamak edge plasma

International Nuclear Information System (INIS)

Cadez, I.; Markelj, S.; Rupnik, Z.; Pelicon, P.

2006-01-01

We are currently conducting a series of different laboratory experimental studies of processes involving vibrationally excited hydrogen molecules that are relevant to fusion edge plasma. A general overview of our activities is presented together with results of studies of hydrogen recombination on surfaces. This includes vibrational spectroscopy of molecules formed by recombination on metal surfaces exposed to the partially dissociated hydrogen gas and recombination after hydrogen permeation through metal membrane. The goal of these studies is to provide numerical parameters needed for edge plasma modelling and better understanding of plasma wall interaction processes. (author)

Excitation-energy influence at the scission configuration

Directory of Open Access Journals (Sweden)

Ramos D.

2017-01-01

Full Text Available Transfer- and fusion-induced fission in inverse kinematics was proven to be a powerful tool to investigate nuclear fission, widening the information of the fission fragments and the access to unstable fissioning systems with respect to other experimental approaches. An experimental campaign for fission investigation has being carried out at GANIL with this technique since 2008. In these experiments, a beam of 238U, accelerated to 6.1 MeV/u, impinges on a 12C target. Fissioning systems from U to Cf are populated through transfer and fusion reactions, with excitation energies that range from few MeV up to 46 MeV. The use of inverse kinematics, the SPIDER telescope, and the VAMOS spectrometer permitted the characterization of the fissioning system in terms of mass, nuclear charge, and excitation energy, and the isotopic identification of the full fragment distribution. The neutron excess, the total neutron multiplicity, and the even-odd staggering in the nuclear charge of fission fragments are presented as a function of the excitation energy of the fissioning system. Structure effects are observed at Z∼50 and Z∼55, where their impact evolves with the excitation energy.

Experimental study of the influence of partner structure in the fusion of the almost symmetrical systems; Etude experimentale de l`influence de la structure des partenaires dans la fusion de systemes presque symetriques

Energy Technology Data Exchange (ETDEWEB)

Stodel-Le Lay, Christelle [Lab. de Physique Corpusculaire, Caen Univ., 14 - Caen (France)

1998-12-04

The cross-sections for the formation of evaporation residues in {sup 70}Zn and {sup 86}Kr reactions with {sup 150}Nd and {sup 130,136}Xe isotopes were measured for excitation energies of the compound nuclei ({sup 216,220,222}Th) varied from 7 MeV to 70 MeV, at the linear accelerator UNILAC of the nuclear facility GSI, Darmstadt (Germany). After de-excitation by evaporation (xn,pxn and {alpha}xn), the residual nuclei are separated from the primary beam and from spurious reaction products by the velocity filter SHIP and implanted into a silicon localization detector. Their subsequent decay via alpha particles with characteristic energies allows us to identify them and to deduce their yields. Experimental fusion-evaporation excitation functions are compared with those leading to the same compound nuclei obtained with other projectile and target combinations and with those calculated with a code developed at GSI. This code allows us to evaluate the evolution of the fission probability as a function of the incident energy for each system. The variation of cross-sections and of the fusion probability is studied as a function of the macroscopic and microscopic variables of the partners. For the synthesis of super-heavy elements, these results demonstrate quantitatively the interest in using partners of fusion with closed shell structures and rich in neurons (the fusion cross-section increases by a factor of 9 for a complementary pair of neutrons). On the other hand, closed shell compound nuclei do not influence the fusion cross-section. It will be worth synthesizing isotopes approaching the predicted stability region, nuclei with Z greater than 110 using neutron rich projectiles coming from secondary beams. (author) 104 refs., 71 figs., 11 tabs.

Mechanical technology unique to laser fusion experimental systems

International Nuclear Information System (INIS)

Hurley, C.A.

1980-01-01

Hardware design for laser fusion experimental machines has led to a combination of engineering technologies that are critical to the successful operation of these machines. These large opto-mechanical systems are dependent on extreme cleanliness, accommodation to efficient maintenance, and high stability. These three technologies are the primary mechanical engineering criteria for laser fusion devices

Investigation of the influence of incomplete fusion on complete fusion of {sup 12}C-induced reactions at {approx} 4-7.2 MeV/nucleon

Energy Technology Data Exchange (ETDEWEB)

Amanuel, F.K. [INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova) (Italy); Zelalem, B.; Chaubey, A.K. [Addis Ababa University, Department of Physics, P.O.Box 1176, Addis Ababa (Ethiopia); Agarwal, Avinash [Bareilly College, Department of Physics, Bareilly (India); Rizvi, I.A.; Maheshwari, Anjana; Ahmed, Tauseef [Aligarh Muslim University, Department of Physics, Aligarh (India)

2011-12-15

In this paper, we present the results of our investigation of reaction dynamics leading to incomplete fusion of heavy ions at moderate excitation energies, especially the influence of incomplete fusion on complete fusion of {sup 12}C -induced reactions at specific energies {approx} 4-7.2M eV/nucleon. Excitation functions of various reaction products populated via complete and/or incomplete fusions of a {sup 12}C projectile with {sup 93}Nb, {sup 59}Co and {sup 52}Cr targets were measured at several specific energies {approx} 4-7.2 MeV/nucleon, using a recoil catcher technique, followed by off-line {gamma}-ray spectrometry. The measured excitation functions were compared with theoretical values obtained using the PACE4 statistical model code. For representative non-{alpha}-emitting channels in the {sup 12}C + {sup 93}Nb system, the experimentally measured excitation functions were, in general, found to be in good agreement with the theoretical predictions. However, for {alpha}-emitting channels in the {sup 12}C + {sup 93}Nb, {sup 12}C + {sup 59}Co, and {sup 12}C + {sup 52}Cr systems, the measured excitation functions were higher than the predictions of the theoretical model code, which may be credited to incomplete fusion reactions at these energies. An attempt was made to estimate the incomplete fusion fraction for the present systems, which revealed that the fraction was sensitive to the projectile energy and mass asymmetry of the entrance channel. (orig.)

Experimental study of the fusion dynamics of 32,34S + 197Au with quasi-elastic scattering

International Nuclear Information System (INIS)

Schuck, T.J.; Dasgupta, M.; Timmers, H.

2000-01-01

Full text: The fusion dynamics of heavy systems, such as 64 Ni + 208 Pb, leading to the synthesis of super-heavy elements is presently not fully understood. Typical beam energies in such reactions are of the order or smaller than the Coulomb barrier height to minimize the excitation energy of the compound system and increase the survival probability of evaporation residues. It is known that at such energies the relative motion of projectile and target couples to internal degrees of freedom of the system, such as collective motion and particle transfer. This can give rise to a distribution of fusion barriers, which generally leads to an enhancement of the fusion cross-section below the Coulomb barrier. The important role of the individual degrees of freedom can be identified by extracting representations of the barrier distribution from fusion excitation functions. Complementary representations can be obtained from measurements of the quasi-elastic or elastic scattering excitation functions at backward angles. The sensitivity of the representations from scattering is limited to the lower energy part of the barrier distribution, which, however, may contain important signatures of positive Q-value neutron transfer channels. Neutron transfer may be a precursor of neutron flow and neck-formation, which are considered in macroscopic models of the fusion of heavy systems. In order to study the influence of neutron transfer in heavy fusion reactions, quasielastic scattering has been measured for 32 , 34 S + 197 Au at energies spanning the Coulomb barrier. The quasi-elastic yield, including inelastic and transfer reactions, was detected at 165 deg with a Si-surface barrier detector. The excitation functions have been normalized to Rutherford scattering, detected at 30 deg using an existing gas ionisation detector. Representations of the barrier distributions have been extracted and are compared with earlier measurements for 32 S + 208 Pb

Experimental approaches to heavy ion fusion

International Nuclear Information System (INIS)

Obayashi, H.; Fujii-e, Y.; Yamaki, T.

1986-01-01

As a feasibility study on heavy-ion-beam induced inertial fusion (HIF) approach, a conceptual plant design called HIBLIC-I has been worked out since 1982. The characteristic features of this design are summarized. To experimentally confirm them and prove them at least in principle, considerations are made on possible experimental programs to give substantial information on these critical phenomena. In HIBLIC-I, an accelerator complex is adopted as driver system to provide 6 beams of 208 Pb +1 ions at 15 GeV, which will be simultaneously focussed on a single shell, three layered target. The target is designed to give an energy gain of 100, so that the total beam energy of 4 MJ with 160 TW power may release 400 MJ fusion energy. A reactor chamber is cylindrical with double-walled structure made of HT-9. There are three layers of liquid Li flow inside the reactor. The innermost layer forms a Li curtain which is effective to recover the residual cavity pressure. A thick upward flow serves as coolant and tritium breeder. Tritium will be recovered by yttrium gettering system. A driver system is operated at the repetition rate of 10 Hz and supplies beams for 10 reactor chambers. Then the plant yield of fusion power becomes 4000 MWt, corresponding a net electric output of 1.5 GW. Experimental programs related to HIBLIC-I is described and discussed, including those for heavy-ion-beam experiments and proposals for lithium curtain by electron beam to clarify the key phenomena in HIBLIC-I cavity. (Nogami, K.)

Atomic data for fusion

Energy Technology Data Exchange (ETDEWEB)

Hunter, H.T.; Kirkpatrick, M.I.; Alvarez, I.; Cisneros, C.; Phaneuf, R.A. (eds.); Barnett, C.F.

1990-07-01

This report provides a handbook of recommended cross-section and rate-coefficient data for inelastic collisions between hydrogen, helium and lithium atoms, molecules and ions, and encompasses more than 400 different reactions of primary interest in fusion research. Published experimental and theoretical data have been collected and evaluated, and the recommended data are presented in tabular, graphical and parametrized form. Processes include excitation and spectral line emission, charge exchange, ionization, stripping, dissociation and particle interchange reactions. The range of collision energies is appropriate to applications in fusion-energy research.

Atomic data for fusion

International Nuclear Information System (INIS)

Hunter, H.T.; Kirkpatrick, M.I.; Alvarez, I.; Cisneros, C.; Phaneuf, R.A.; Barnett, C.F.

1990-07-01

This report provides a handbook of recommended cross-section and rate-coefficient data for inelastic collisions between hydrogen, helium and lithium atoms, molecules and ions, and encompasses more than 400 different reactions of primary interest in fusion research. Published experimental and theoretical data have been collected and evaluated, and the recommended data are presented in tabular, graphical and parametrized form. Processes include excitation and spectral line emission, charge exchange, ionization, stripping, dissociation and particle interchange reactions. The range of collision energies is appropriate to applications in fusion-energy research

Measurements of fusion cross sections of 16O+46,50Ti systems

International Nuclear Information System (INIS)

Liguori Neto, R.

1986-01-01

Excitation functions for complete fusion of the systems 16 O + 46,50 Ti, with50)Ti, energies near and below the Coulomb barrier, were measured. With the use of the in-beam and out of beam γ spectroscopy, the formation of the compound nucleus was experimentally detected. The fusion cross was then attained by the sum of all observed compound nucleus decay channels. The limitation and advantages of measurements methods are discussed. Theoretical analysis of the experimental results using the semi-classical barrier penetration model allowed us to obtain the fusion barrier height and radius for the studied systems. These values are in good agreement with others reported for this mass range. Using the unidimensional barrier penetration model with different nuclear potentials, describing the heavy ion interactions gave theoretical fusion cross section values systematically smaller than our measured values in the energy region below the Coulomb barrier. The introduction of the nuclear surface zero point vibrations enhances the theoretical fusion cross sections in the sub-Coulomb region, but simultaneoulsy introduces an isotopic difference in the fusion excitation functions that is not observed experimentally. The statistical model predictions for the compound nucleous decay (calculated by the CASCADE program) show reasonable agreement for the more intense decay channels. (author) [pt

Measurement and analysis of excitation functions in 16O + 103Rh system in the excitation energy range ≅ 2-4 MeV/A

International Nuclear Information System (INIS)

Singh, Devendra P.; Unnati; Sharma, Manoj Kumar; Singh, Pushpendra P.; Singh, B.P.; Prasad, R.; Gupta, Sunita; Rakesh Kumar; Bhardwaj, H.D.

2006-01-01

In the present work, excitation functions for seven evaporation residues (ERs) produced via complete fusion and incomplete fusion processes in 16 O + 103 Rh system have been measured in the energy range ≅ 47-85 MeV, using recoil catcher technique followed by off-line gamma-ray spectrometry. Comparison of the experimental data with statistical model based computer code PACE 2 revealed dominance of incomplete fusion in reactions involving alpha-emission channels. To the best of our knowledge these reactions are being reported for the first time

Innovative safety ideas for fusion experimental machines

International Nuclear Information System (INIS)

Brereton, S.J.; Gouge, M.; Piet, S.J.; Merrill, B.J.; Holland, D.F.; Sze, D.K.

1990-01-01

Throughout the early stages of design of fusion experimental devices, such as ITER, safety experts have worked with designers to incorporate safety features into the design. Recent efforts have focused on passive safety features. Although designs of near-term fusion machines may appear consistent with expected regulatory requirements, the safety characteristics can potentially be more attractive. Here, a variety of suggestions that appear promising in terms of improving safety are given. These include new concepts, innovative technologies, further support of past concepts, and possible modification to operating scenarios. Some technical discussion on the feasibility of the proposals is provided. The ideas are generally conceptual at this stage and require further assessment and development work. However, each has the potential for enhancing the safety of experimental devices. 33 refs., 6 figs., 9 tabs

Measurements of fusion cross sections of the 16O+46,50Ti systems

International Nuclear Information System (INIS)

Liguori Neto, R.

1986-01-01

Excitation functions for complete fusion of the systems 16 O + 46,50 Ti, with energies near and below the Coulomb barrier, were measured. With the use of the in-beam and out of beam γ spectroscopy, the formation of the compound nucleus was experimentally detected. The fusion cross section was then attained by the sum of all observed compound nucleus decay channels. The limitation and advantages of measurements methods are discussed. Theoretical analysis of the experimental results using the semi-classical barrier penetration model allowed us to obtain the fusion barrier height and radius for the studied systems. These values are in good agreement with others reported for this mass range. Using the unidimensional barrier penetration model with different nuclear potentials, describing the heavy ion interactions gave theoretical fusion cross section values systematically smaller than our measured values in the energy region below the Coulomb barrier. The introduction of the nuclear surface zero point vibrations enhances the theoretical fusion cross sections in the sub-Coulomb region, but simultaneously introduces an isotopic difference in the fusion excitation functions that is not observed experimentally. The statistical model predictions for the compound nucleus decay (calculated by the CASCADE program) show reasonable agreement for the more intense decay channels [pt

ITER: the first experimental fusion reactor

International Nuclear Information System (INIS)

Rebut, P.H.

1995-01-01

The International Thermonuclear Experimental Reactor (ITER) project is a multiphased project, at present proceeding under the auspices of the International Atomic Energy Agency according to the terms of a four-party agreement between the European Atomic Energy Community, the Government of Japan, the Government of the USA and the Government of Russia (''the parties''). The project is based on the tokamak, a Russian invention which has been brought to a high level of development and progress in all major fusion programs throughout the world.The objective of ITER is to demonstrate the scientific and technological feasibility of fusion energy for commercial energy production and to test technologies for a demonstration fusion power plant. During the extended performance phase of ITER, it will demonstrate the characteristics of a fusion power plant, producing more than 1500MW of fusion power.The objective of the engineering design activity (EDA) phase is to produce a detailed, complete and fully integrated engineering design of ITER and all technical data necessary for the future decision on the construction of ITER.The ITER device will be a major step from present fusion experiments and will encompass all the major elements required for a fusion reactor. It will also require the development and the implementation of major new components and technologies.The inside surface of the plasma containment chamber will be designed to withstand temperature of up to 500 C, although normal operating temperatures will be substantially lower. Materials will have to be carefully chosen to withstand these temperatures, and a high neutron flux. In addition, other components of the device will be composed of state-of-the-art metal alloys, ceramics and composites, many of which are now in the early stage of development of testing. (orig.)

Fusion power and its prospects

International Nuclear Information System (INIS)

Kammash, T.

1981-01-01

Recent progress in research towards the development of fusion power is reviewed. In the magnetic approach, the impressive advances made in Tokamak research in the past few years have bolstered the confidence that experimental Tokamak devices currently under construction will demonstrate the break-even condition or scientific feasibility of fusion power. Exciting and innovative ideas in mirror magnetic confinement are expected to culminate in high-Q devices which will make open-ended confinement a serious contender for fusion reactors. In the inertial confinement approach, conflicting pellet temperature requirements have placed severe constraints on useful laser intensities and wavelengths for laser-driven fusion. Relativistic electron beam fusion must solve critical focusing and pellet coupling problems, and the newly proposed heavy ion beam fusion, though feasible and attractive in principle, requires very high energy particles for which the accelerator technology may not be available for some time to come

How does incomplete fusion show up at slightly above barrier energies?

Directory of Open Access Journals (Sweden)

Prasad R.

2012-02-01

Full Text Available Experimental results on the onset of incomplete fusion at slightly above barrier energies are discussed in this paper. Spin-distributions of evaporation residues populated via complete and/or incomplete fusion of 12C,16O (Elab ≈ 4–7 MeV with 169Tm have been measured to probe associated ℓ–values. Particle (Z=1,2 – γ – coincidence technique has been used for channel selection. Entirely different entry state spin populations have been observed during the de-excitation of complete and incomplete composites. The complete fusion residues are found to be strongly fed over a broad spin range. While, a narrow range feeding for only high spin states has been observed in case of incomplete fusion residues. In the present work, incomplete fusion is shown to be a promising tool to populate high spin states in final reaction products. For better insight into the onset and strength of incomplete fusion, the relative contributions of complete and incomplete fusion have been deduced from the analysis of excitation functions and forward recoil ranges. A significant fraction of ICF has been observed even at energy as low as ≈ 7% above the barrier. The relative strengths of complete and incomplete fusion deduced from the analysis of forward-recoil-ranges and excitation functions complement each other. All the available results are discussed in light of the Morgenstern’s mass-asymmetry systematics. Incomplete fusion fraction is found to be large for more mass-asymmetric systems for individual projectiles, which points towards the projectile structure effect on incomplete fusion fraction. Experimentally measured forward ranges of recoils complement the existence of incomplete fusion at slightly above barrier energies, where more than one linear-momentum-transfer components associated with full- and/or partial-fusion of projectile(s have been observed. Present results conclusively demonstrate the possibility to selectively populate high spin states

Angular momentum effects in subbarrier fusion

International Nuclear Information System (INIS)

Halbert, M.L.; Beene, J.R.; Hensley, D.C.; Honkanen, K.; Semkow, T.M.; Abenante, V.; Sarantites, D.G.; Li, Z.

1987-01-01

The authors discuss angular-momentum distributions σ l for the compound nucleus 164 Yb deduced from measurements of γ-ray multiplicity for all significant evaporation residues from fusion of 64 Ni and 100 Mo and 16 O + 148 Sm. At the lowest bombarding energies the σ l extend to higher l values than do predictions that include coupling of the principal inelastic channels, even if the coupling strengths are increased to match the experimental excitation function. Likewise, σ l from an energy-dependent real potential fitted to the excitation function fails to reproduce the experimental σ l distribution. No effects attributed to superdeformation were observed

Some considerations of ''cold fusion'' including the calculation of fusion rates in molecules of hydrogen isotopes

International Nuclear Information System (INIS)

Cowley, S.C.; Kulsrud, R.M.

1989-11-01

We calculate the fusion reaction rates in molecules of hydrogen isotopes. The rates are calculated analytically (for the first time) as an asymptotic expansion in the ratio of the electron mass to the reduced mass of the nucleii. The fusion rates of the P-D, D-D, and D-T reactions are given for a variable electron mass by a simple analytic formula. However, we do not know any mechanism by which a sufficiently localized electron in solid can have an 'effective mass' large enough to explain the result of Fleischman and Pons (FP). This calculation indicates that P-D rates should exceed D-D rates for D-D fusion rates less than approximately 10 -23 per molecule per second. The D-D fusion rate is enhanced by a factor of 10 5 at 10,000 degree K if the excited vibrational states are populated with a Boltzmann distribution and the rotational excitations suppressed. The suggestion that experimental results could be explained by bombardment of cold deuterons by kilovolt deuterons is shown to be an unlikely from an energetic point of view. 12 refs., 3 figs., 1 tab

Compressed Gas Safety for Experimental Fusion Facilities

Energy Technology Data Exchange (ETDEWEB)

Lee C. Cadwallader

2004-09-01

Experimental fusion facilities present a variety of hazards to the operators and staff. There are unique or specialized hazards, including magnetic fields, cryogens, radio frequency emissions, and vacuum reservoirs. There are also more general industrial hazards, such as a wide variety of electrical power, pressurized air, and cooling water systems in use, there are crane and hoist loads, working at height, and handling compressed gas cylinders. This paper outlines the projectile hazard assoicated with compressed gas cylinders and mthods of treatment to provide for compressed gas safety. This information should be of interest to personnel at both magnetic and inertial fusion experiments.

Radiation environment of fusion experimental reactor

International Nuclear Information System (INIS)

Mori, Seiji; Seki, Yasushi

1988-01-01

Next step device (experimental reactor), which is planned to succeed the large plasma experimental devices such as JT-60, JET and TFTR, generates radiation (neutron + gamma ray) during its operation. Radiation (neutronic) properties of the material are basis for the study on neutron utilization (energy recovery and tritium breeding), material selection (irradiation damage and lifetime evaluation) and radiation safety (personnel exposure and radiation waste). It is necessary, therefore, to predict radiation behaviour in the reactor correctly for the engineering design of the reactor. This report describes the outline of the radiation environment of the reactor based on the information obtained by the neutronic and shielding design calculation of the fusion experimental reactor (FER). (author)

Cold fusion in perspective

International Nuclear Information System (INIS)

Sanford, L.

1989-01-01

Since early April a great deal of excitement has been created over the Fleischmann/Pons cold fusion experiment, which if it performs as advertised, could turn out to be mankind's best hope of heading off the energy crisis scheduled for early in the next century. Dozens of groups around the world are now attempting to duplicate the experiment to see if Fleischmann and Pons' discovery is an experimental mistake, an unknown electrochemical effect or a new kind of fusion reaction. This article puts the experiment into the perspective of today and looks at how it might affect the energy scene tomorrow if it should turn out to be commercially exploitable. (author)

Elastic, excitation, ionization and charge transfer cross sections of current interest in fusion energy research

Energy Technology Data Exchange (ETDEWEB)

Schultz, D.R.; Krstic, P.S. [Oak Ridge National Lab. TN (United States). Physics Div.

1997-01-01

Due to the present interest in modeling and diagnosing the edge and divertor plasma regions in magnetically confined fusion devices, we have sought to provide new calculations regarding the elastic, excitation, ionization, and charge transfer cross sections in collisions among relevant ions, neutrals, and isotopes in the low-to intermediate-energy regime. We summarize here some of our recent work. (author)

Electron-impact excitation and recombination of molecular cations in edge fusion plasma: application to H2+and BeD+

Science.gov (United States)

Pop, Nicolina; Iacob, Felix; Mezei, Zsolt; Motapon, Ousmanou; Niyonzima, Sebastien; Schneider, Ioan

2017-10-01

Dissociative recombination, ro-vibrational excitation and dissociative excitation of molecular cations with electrons are major elementary process in the kinetics and in the energy balance of astrophysically-relevant ionized media (supernovae, interstellar molecular clouds, planetary ionospheres, early Universe), in edge fusion and in many other cold media of technological interest. For the fusion plasma edge, extensive cross sections and rate coefficients have been produced for reactions induced on HD+, H2+ and BeD+ using the Multichannel Quantum Defect Theory (MQDT). Our calculations resulted in good agreement with the CRYRING (Stockholm) and TSR (Heidelberg) magnetic storage ring results, and our approach is permanently improved in order to face the new generation of electrostatic storage rings, as CSR (Heidelberg) and DESIREE (Stockholm). Member of APS Reciprocal Society: European Physics Society.

Vibrational motions in rotating nuclei studied by Coulomb excitations

Energy Technology Data Exchange (ETDEWEB)

Shimizu, Yoshifumi R [Kyushu Univ., Fukuoka (Japan). Dept. of Physics

1998-03-01

As is well-known Coulomb excitation is an excellent tool to study the nuclear collective motions. Especially the vibrational excitations in rotating nuclei, which are rather difficult to access by usual heavy-ion fusion reactions, can be investigated in detail. Combined with the famous 8{pi}-Spectrometer, which was one of the best {gamma}-ray detector and had discovered some of superdeformed bands, such Coulomb excitation experiments had been carried out at Chalk River laboratory just before it`s shutdown of physics division. In this meeting some of the experimental data are presented and compared with the results of theoretical investigations. (author)

Excitation functions for some evaporation residues identified in the interaction of 20Ne and 93Nb at moderate excitation energies

International Nuclear Information System (INIS)

Agarwal, Avinash; Rizvi, I.A.; Gupta, Meenal; Ahamad, Tauseef; Ghugre, S.S.; Sinha, A.K.; Chaubey, A.K.

2008-01-01

With the motivation of studying the complete and incomplete fusion reactions, excitation functions for the reactions 93 Nb(Ne, p2n) 110 Sn, 93 Nb(Ne, 2pn) 110 In, 93 Nb(Ne, 2p2n) 109 In, 93 Nb(Ne, αn) 108 In, 93 Nb(Neα2n) 107 In and 93 Nb(Ne, α p n) 107 Cd have been measured at the incident energy ranging from 91.4 MeV - 145 MeV. The well established activation technique followed by off line high purity gamma- ray spectroscopy was employed. The measured excitation functions were compared with the statistical model calculations by using the codes ALICE-91 and Pace-4. The effect of variation of different parameters including level density parameter involved in these codes has also been studied. Excellent agreement was found between theoretical and experimental values in some of the fusion evaporation reaction channels. However, significant enhancement of cross-section observed in α-emission channels may be due to incomplete fusion process. (author)

Fusion barrier distributions and fission anisotropies

International Nuclear Information System (INIS)

Hinde, D.J.; Morton, C.R.; Dasgupta, M.; Leigh, J.R.; Lestone, J.P.; Lemmon, R.C.; Mein, J.C.; Newton, J.O.; Timmers, H.; Rowley, N.; Kruppa, A.T.

1995-01-01

Fusion excitation functions for 16,17 O+ 144 Sm have been measured to high precision. The extracted fusion barrier distributions show a double-peaked structure interpreted in terms of coupling to inelastic collective excitations of the target. The effect of the positive Q-value neutron stripping channel is evident in the reaction with 17 O. Fission and evaporation residue cross-sections and excitation functions have been measured for the reaction of 16 O+ 208 Pb and the fusion barrier distribution and fission anisotropies determined. It is found that the moments of the fusion l-distribution determined from the fusion and fission measurements are in good agreement. ((orig.))

Cross-sections and average angular momenta in fusion reactions near the coulomb barrier

International Nuclear Information System (INIS)

Dasgupta, M.

1992-01-01

In recent years there has been an increasing interest in the study of heavy ion collisions near the Coulomb barrier. This has been triggered mainly by the observations of enhancements by factors of about one to two order of magnitude in sub-Coulomb barrier fusion (SBF) cross-sections between medium mass nuclei, as compared to predictions based on one-dimensional barrier penetration model (l-d BPM). Though, a considerable amount of work both theoretical and experimental has been done in this field, a complete understanding of the SBF phenomenon has not yet been achieved. The relation between fusion excitation function and angular momentum (l) distribution in SBF reactions is a topic of current interest. It is believed that l-distributions provide a more stringent test of SBF models that the excitation functions alone. Simultaneous measurement of l-distribution (or its moments) and fusion excitation function is expected to lead to a better understanding of the relationship between these two qualities. Such information has been obtained in experiments done at pelletron accelerator facility. In the present talk the measurement of fusion cross-sections and the method of determination of average l from partial evaporation residue cross-section has been elaborated. An analysis of the experimental data on the basis of some of the SBF models has been discussed briefly. (author). 13 refs

Methodology to estimate parameters of an excitation system based on experimental conditions

Energy Technology Data Exchange (ETDEWEB)

Saavedra-Montes, A.J. [Carrera 80 No 65-223, Bloque M8 oficina 113, Escuela de Mecatronica, Universidad Nacional de Colombia, Medellin (Colombia); Calle 13 No 100-00, Escuela de Ingenieria Electrica y Electronica, Universidad del Valle, Cali, Valle (Colombia); Ramirez-Scarpetta, J.M. [Calle 13 No 100-00, Escuela de Ingenieria Electrica y Electronica, Universidad del Valle, Cali, Valle (Colombia); Malik, O.P. [2500 University Drive N.W., Electrical and Computer Engineering Department, University of Calgary, Calgary, Alberta (Canada)

2011-01-15

A methodology to estimate the parameters of a potential-source controlled rectifier excitation system model is presented in this paper. The proposed parameter estimation methodology is based on the characteristics of the excitation system. A comparison of two pseudo random binary signals, two sampling periods for each one, and three estimation algorithms is also presented. Simulation results from an excitation control system model and experimental results from an excitation system of a power laboratory setup are obtained. To apply the proposed methodology, the excitation system parameters are identified at two different levels of the generator saturation curve. The results show that it is possible to estimate the parameters of the standard model of an excitation system, recording two signals and the system operating in closed loop with the generator. The normalized sum of squared error obtained with experimental data is below 10%, and with simulation data is below 5%. (author)

The effects of one-body dissipation and collective inertias in heavy-ion scattering and fusion

International Nuclear Information System (INIS)

Stryjewski, J.S.

1989-01-01

A classical dynamical model of heavy ion scattering and fusion is presented. The model includes deformations, deformation-dependent inertias and one-body friction in both the entrance and exit channels. The deformation-dependent inertias are calculated using a hydrodynamic approach and the one-body friction is determined with the classical wall friction formalism. This model is used to study the effects of one-body friction and collective inertias on strongly damped heavy ion reactions and fusion. Quantum-mechanical calculations suggest that the strength of classical one-body friction, as calculated by the wall formalism, is too large by a factor of 3. Therefore, the fusion excitation functions for the reactions: 16 O + 16 O, 28 Si + 28 Si, 40 Ca + 40 Ca and 56 Fe + 56 Fe are calculated and compared with similar calculations in which the strength of the wall friction has been reduced by a factor of 3. Calculations using the full wall friction reproduce the experimental fusion excitation functions more accurately than calculations using the weaker wall friction. Also, because hydrodynamical inertias are the smallest possible classical inertias, the fusion excitation functions for: 16 O + 16 O, 28 Si + 28 Si, 40 Ca + 40 Ca and 56 Fe + 56 Fe are calculated with the size of the collective inertias increased by a factor of 2 over the hydrodynamical values. Once again, calculations using hydrodynamical collective inertias reproduce the experimental fusion excitation functions more accurately than calculations using the larger collective inertias. The effects of one-body friction and collective inertias on heavy ion scattering are also investigated; reaction times, scattering angles and energy loss are determined as functions of energy and angular momentum for the reactions 98 Mo + 98 Mo and 238 U + 238 U

Some thoughts on a simple mechanism for the 2H + 2H → 4He cold fusion reaction

International Nuclear Information System (INIS)

Park, A.E.

1993-01-01

A speculative mechanism for the creation of 4 He using cold fusion is proposed. The nuclear transformation can be made by the fusion of two excited rotating ground states of deuterium into a highly excited rotating ground state of 4 He. Under compression and relatively stable conditions, the formation of such a bound, stretched-out pnnp state of 4 He would be favored (with respect to Coulomb repulsion) over other nuclear ground states without as much angular momentum. The reaction likely occurs at the surface of palladium. A more descriptive name for this reaction is compressed-rotational-shielded (CRS) fusion. Potential experimental conditions for enhancing the initiation of CRS fusion are discussed. 8 refs., 2 figs

Applications of Skyrme energy-density functional to fusion reactions spanning the fusion barriers

International Nuclear Information System (INIS)

Liu Min; Wang, Ning; Li Zhuxia; Wu Xizhen; Zhao Enguang

2006-01-01

The Skyrme energy density functional has been applied to the study of heavy-ion fusion reactions. The barriers for fusion reactions are calculated by the Skyrme energy density functional with proton and neutron density distributions determined by using restricted density variational (RDV) method within the same energy density functional together with semi-classical approach known as the extended semi-classical Thomas-Fermi method. Based on the fusion barrier obtained, we propose a parametrization of the empirical barrier distribution to take into account the multi-dimensional character of real barrier and then apply it to calculate the fusion excitation functions in terms of barrier penetration concept. A large number of measured fusion excitation functions spanning the fusion barriers can be reproduced well. The competition between suppression and enhancement effects on sub-barrier fusion caused by neutron-shell-closure and excess neutron effects is studied

Incomplete fusion studies

International Nuclear Information System (INIS)

Singh, B.P.

2011-01-01

In order to study the incomplete fusion reaction dynamics at energies ≅ 4-7 MeV/nucleon, several experiments have been carried out using accelerator facilities available in India. The measurements presented here cover a wide range of projectile-target combinations and enhance significantly our knowledge about incomplete fusion reaction dynamics. Here, the three sets of measurements have been presented; (i) excitation functions, (ii) forward recoil range distributions and (iii) the spin distributions. The first evidence of these reactions has been obtained from the measurement and analysis of excitation functions for xn/αxn/2αxn-channels. The measured excitation functions have been analyzed within the framework of compound nucleus model. The results obtained indicate the occurrence of fusion incompleteness at low beam energies. However, in order to determine the relative contribution of complete and incomplete fusion reaction processes, the recoil range distributions of the heavy residues have also been measured and analyzed within the framework of breakup fusion model which confirmed the fusion incompleteness in several heavy ion reactions involving α-emitting reaction channels. Further, in order to study the role of l-values in these reactions the spin distributions of the residues populated in case of complete and incomplete channels have been measured and are found to be distinctly different. The analysis of the data on spin distribution measurements indicate that the mean values of driving input angular momenta associated with direct-α-emitting (incomplete fusion) channels are higher than that observed for fusion-evaporation xn or α-emitting (complete fusion) channels, and is found to increase with direct α-multiplicity in the forward cone. One of the important conclusions drawn in the present work is that, there is significant incomplete fusion contribution even at energies slightly above the barrier. Further, the projectile structure has been found to

Dust removal system for fusion experimental reactors

International Nuclear Information System (INIS)

Onozuka, M.; Ueda, Y.; Takahashi, K.; Oda, Y.; Seki, Y.; Ueda, S.; Aoki, I.

1995-01-01

Development of a dust removal system using static electricity has been conducted. It is envisioned that the system can collect and transport dust under vacuum. In the system, the dust is charged by dielectric polarization and floated by an electrostatic attraction force that is generated by the DC electric field. The dust is then transported by the electric curtain formed by the three-phase AC electric field. Experimental investigation has been conducted to examine the characteristics of the system. Current research results indicate that the dust removal system using static electricity can be used for fusion experimental reactors

Dust removal system for fusion experimental reactors

Energy Technology Data Exchange (ETDEWEB)

Onozuka, M.; Ueda, Y.; Takahashi, K.; Oda, Y. [Mitsubishi Heavy Industries, Ltd., Yokohama (Japan); Seki, Y.; Ueda, S.; Aoki, I. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan)

1995-12-31

Development of a dust removal system using static electricity has been conducted. It is envisioned that the system can collect and transport dust under vacuum. In the system, the dust is charged by dielectric polarization and floated by an electrostatic attraction force that is generated by the DC electric field. The dust is then transported by the electric curtain formed by the three-phase AC electric field. Experimental investigation has been conducted to examine the characteristics of the system. Current research results indicate that the dust removal system using static electricity can be used for fusion experimental reactors.

Diagnostics of MCF plasmas using Lyman-α fluorescence excited by one or two photons

International Nuclear Information System (INIS)

Voslamber, D.

1998-11-01

Laser-induced Lyman-α fluorescence of the hydrogen isotopes is investigated with regard to diagnostic applications in magnetically confined fusion plasmas. A formal analysis is presented for two excitation schemes: one-photon and Doppler-free two-photon excitation. The analysis includes estimates of the expected experimental errors arising from the photon noise and from the sensitivity of the observed fluorescence signals to variations of the plasma and laser parameters. Both excitation schemes are suitable primarily for application in the plasma edge, but even in the plasma bulk of large machines they can still be applied in combination with a diagnostic neutral beam. The two-photon excitation scheme is particularly attractive because it involves absorption spectra that are resolved within the Doppler width. This implies a large diagnostic potential and in particular offers a way to measure the deuterium-tritium fuel mix in fusion reactors. (author)

Conceptual design of Fusion Experimental Reactor (FER)

International Nuclear Information System (INIS)

Tone, T.; Fujisawa, N.

1983-01-01

Conceptual design studies of the Fusion Experimental Reactor (FER) have been performed. The FER has an objective of achieving selfignition and demonstrating engineering feasibility as a next generation tokamak to JT-60. Various concepts of the FER have been considered. The reference design is based on a double-null divertor. Optional design studies with some attractive features based on advanced concepts such as pumped limiter and RF current drive have been carried out. Key design parameters are; fusion power of 440 MW, average neutron wall loading of 1MW/m 2 , major radius of 5.5m, plasma minor radius of 1.1m, plasma elongation of 1.5, plasma current of 5.3MA, toroidal beta of 4%, toroidal field on plasma axis of 5.7T and tritium breeding ratio of above unity

Experimental results on advanced inertial fusion schemes obtained within the HiPER project

International Nuclear Information System (INIS)

Batani, Dimitri; Santos, Jorge J.; Schurtz, Guy; Hulin, Sebastien; Ribeyre, Xavier; Nicolai, Philippe; Vauzour, Benjamin; Dorchies, Fabien; Gizzi, Leonida A.; Koester, Petra; Labate, Luca; Honrubia, Javier; Antonelli, Luca; Morace, Alessio; Volpe, Luca; Nazarov, Wiger; Pasley, John; Richetta, Maria; Lancaster, Kate; Spindloe, Christopher; Tolley, Martin; Neely, David; Kozlova, Michaela; Nejdl, Jaroslav; Rus, Bedrich; Wolowski, Jerzy; Badziak, Jan

2012-01-01

This paper presents the results of experiments conducted within the Work Package 10 (fusion experimental programme) of the HiPER project. The aim of these experiments was to study the physics relevant for advanced ignition schemes for inertial confinement fusion, i.e. the fast ignition and the shock ignition. Such schemes allow to achieve a higher fusion gain compared to the indirect drive approach adopted in the National Ignition Facility in United States, which is important for the future inertial fusion energy reactors and for realising the inertial fusion with smaller facilities. (authors)

Experimental Investigation of Ternary Alloys for Fusion Breeding Blankets

Energy Technology Data Exchange (ETDEWEB)

Choi, B. William [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chiu, Ing L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-10-26

Future fusion power plants based on the deuterium-tritium (DT) fuel cycle will be required to breed the T fuel via neutron reactions with lithium, which will be incorporated in a breeding blanket that surrounds the fusion source. Recent work by LLNL proposed the used of liquid Li as the breeder in an inertial fusion energy (IFE) power plant. Subsequently, an LDRD was initiated to develop alternatives ternary alloy liquid metal breeders that have reduced chemical reactivity with water and air compared to pure Li. Part of the work plan was to experimentally investigate the phase diagrams of ternary alloys. Of particular interest was measurement of the melt temperature, which must be low enough to be compatible with the temperature limits of the steel used in the construction of the chamber and heat transfer system.

Neutron rich clusters and the dynamics of fission and fusion

International Nuclear Information System (INIS)

Armbruster, P.

1988-07-01

In this lecture I want to discuss experimental evidence for the appearance of cluster aspects in the dynamics of large rearrangement processes, as fusion and fission. Clusters in the sense as used in my lecture are the strongly bound doubly magic nuclei as 20 Ca 28 48 , 28 Ni 50 78 , 132 50 Sn 82 , and 208 82 Pb 126 and the superheavy nucleus 298 114 184 . Two of these nuclei, 78 Ni and 298 114 have not yet been identified. I discuss first the experimental findings from heavy element production. Then I cover the stability of cluster aspects to intrinsic excitation energy in fusion and fission. (orig./HSI)

Development step toward fusion power plant and role of experimental reactor ITER

International Nuclear Information System (INIS)

Hiwatari, Ryouji; Asaoka, Yoshiyuki; Okano, Kunihiko

2005-01-01

The development of fusion energy is going into the experimental reactor stage, and the thermal energy from the fusion reaction will be generated in a plant scale through the ITER (International Thermonuclear Experimental Reactor) project. The remaining critical issue toward the realization of fusion energy is to map out the development strategy. Recently early realization approach as for the fusion energy development is being discussed in Japan, Europe, and the United States. This approach implies that the devices for a Demo reactor and a proto-type reactor as seen in the fast breeder reactor are combined into a single device in order to advance the fusion energy development. On the other hand, a clear development road map for fusion energy hasn't been suggested yet, and whether that early realization approach is feasible or not is still ambiguous. In order to realize the fusion energy as an user-friendly energy system, the suggestion of the development missions and the road map from the user-side point of view is instructive not only to Japanese but also to other country's development policy after the ITER project. In this report, first of all, the development missions from the user's point of view have been structured. Second, the development target required to demonstrate net electric generation and to introduce the fusion energy into the market is investigated, respectively. This investigation reveals that the completion of the ITER reference operation gives the outlook toward the demonstration of net electric generation and that the completion of the ITER advanced operation gives the possibility to introduce the fusion energy into the market. At last, the electric demonstration power plant Demo-CREST and the commercial power plant CREST are proposed to construct the development road map for fusion energy. (author)

Conceptual design study of Fusion Experimental Reactor (FY87FER)

International Nuclear Information System (INIS)

1988-05-01

The design study of Fusion Experimental Reactor(FER) which has been proposed to be the next step fusion device has been conducted by JAERI Reactor System Laboratory since 1982 and by FER design team since 1984. This is the final report of the FER design team program and describes the results obtained in FY1987 (partially in FY1986) activities. The contents of this report consist of the reference design which is based on the guideline in FY1986 by the Subcomitees set up in Nuclear Fusion Council of Atomic Energy Commission of Japan, the Low-Physics-Risk reactor design for achieving physics mission more reliably and the system study of FER design candidates including above two designs. (author)

Remote welding and cutting techniques for fusion experimental reactors

International Nuclear Information System (INIS)

Onozuka, M.; Ishide, T.; Oda, Y.; Nagaoka, E.; Ue, K.; Kamei, H.

1995-01-01

Experimental investigation of the YAG laser cutting/welding and plasma gouging techniques has been conducted to examine their suitability for remote maintenance systems in future fusion experimental reactors. Using a hybrid beam coupling system, two laser beams of 500W and 740W powers were successfully combined to provide a 1,240W beam power. The combined laser was transmitted through the optical fiber for cutting and welding. The transmission loss for the beams is in the range of 13% to 14%, which is low. As for plasma gouging, the shallow gouging made a groove measuring 10 mm in width and 4 mm in depth on the stainless steel plates at a traversing speed of 75 cm/min, while the deep gouging made a groove of 12 mm in width and 7.5 mm in depth at a traversing speed of 50 cm/min. In addition, it was found that the shallow gouging did not leave byproducts from the material, providing a clean surface. Based on the findings, it is shown that the YAG laser cutting/welding and plasma gouging techniques can be us3ed for remote welding and cutting in future fusion experimental reactors

Remote welding and cutting techniques for fusion experimental reactors

Energy Technology Data Exchange (ETDEWEB)

Onozuka, M.; Ishide, T.; Oda, Y.; Nagaoka, E.; Ue, K.; Kamei, H. [Mitsubishi Heavy Industries, Ltd., Yokohama (Japan)

1995-12-31

Experimental investigation of the YAG laser cutting/welding and plasma gouging techniques has been conducted to examine their suitability for remote maintenance systems in future fusion experimental reactors. Using a hybrid beam coupling system, two laser beams of 500W and 740W powers were successfully combined to provide a 1,240W beam power. The combined laser was transmitted through the optical fiber for cutting and welding. The transmission loss for the beams is in the range of 13% to 14%, which is low. As for plasma gouging, the shallow gouging made a groove measuring 10 mm in width and 4 mm in depth on the stainless steel plates at a traversing speed of 75 cm/min, while the deep gouging made a groove of 12 mm in width and 7.5 mm in depth at a traversing speed of 50 cm/min. In addition, it was found that the shallow gouging did not leave byproducts from the material, providing a clean surface. Based on the findings, it is shown that the YAG laser cutting/welding and plasma gouging techniques can be us3ed for remote welding and cutting in future fusion experimental reactors.

Electrical insulation and conduction coating for fusion experimental devices

International Nuclear Information System (INIS)

Onozuka, Masanori; Tsujimura, Seiji; Toyoda, Masahiko; Inoue, Masahiko; Abe, Tetsuya; Murakami, Yoshio

1996-01-01

The development of electrical insulation and conduction coating methods that can be applied to large components of fusion experimental devices has been investigated. A thermal spraying method is used to coat the insulation or conduction materials on the structural components because of its applicability for large surfaces. The insulation material chosen was Al 2 O 3 , while Cr 3 C 2 -NiCr and WC-NiCr were chosen as conduction materials. These materials were coated on stainless steel substrates to examine the basic characteristics of the coated layers, such as their adhesive strength to the substrate, thermal shock resistance, electrical resistance, dielectric breakdown voltage, and thermal conductivity. It was found that they have sufficient electrical insulation and conduction properties, respectively. In addition, the sliding tests of the coated layers showed adequate frictional properties. The spraying method was tested on a 100- x 1000-mm surface and found to be applicable for large surfaces of experimental fusion devices. 9 refs., 6 figs., 15 tabs

Excitation functions for some Ne induced reactions with Holmium: incomplete fusion vs complete fusion

International Nuclear Information System (INIS)

Agarwal, Avinash; Kumar, Munish; Sharma, Anjali; Rizvi, I.A.; Ahamad, Tauseef; Ghugre, S.S.; Sinha, A.K.; Chaubey, A.K.

2010-01-01

Reactions induced by 20 Ne are expected to be considerably more complex than those of 12 C, and 16 O. As a part of the ongoing program to understand CF and ICF reaction mechanisms, it is of great interest to see whether the same experimental technique yield similarly valuable information for 20 Ne induced reactions. In this present work an attempt has been made to measure the excitation functions for fifteen evaporation residues (ERs) identified in the interaction of 20 Ne + 165 Ho system in the energy range 4 -7 MeV/A

Fusion Materials Irradiation Test Facility: experimental capabilities and test matrix

International Nuclear Information System (INIS)

Opperman, E.K.

1982-01-01

This report describes the experimental capabilities of the Fusion Materials Irradiation Test Facility (FMIT) and reference material specimen test matrices. The description of the experimental capabilities and the test matrices has been updated to match the current single test cell facility ad assessed experimenter needs. Sufficient detail has been provided so that the user can plan irradiation experiments and conceptual hardware. The types of experiments, irradiation environment and support services that will be available in FMIT are discussed

Cold fusion, Alchemist's dream

International Nuclear Information System (INIS)

Clayton, E.D.

1989-09-01

In this report the following topics relating to cold fusion are discussed: muon catalysed cold fusion; piezonuclear fusion; sundry explanations pertaining to cold fusion; cosmic ray muon catalysed cold fusion; vibrational mechanisms in excited states of D 2 molecules; barrier penetration probabilities within the hydrogenated metal lattice/piezonuclear fusion; branching ratios of D 2 fusion at low energies; fusion of deuterons into 4 He; secondary D+T fusion within the hydrogenated metal lattice; 3 He to 4 He ratio within the metal lattice; shock induced fusion; and anomalously high isotopic ratios of 3 He/ 4 He

Experimental investigation of particle-hole excitations in 91Nb

International Nuclear Information System (INIS)

Singh, Purnima; Palit, R.; Choudhury, D.

2014-01-01

Investigation of high-spin states in nuclei near N = 50 shell closure have attracted considerable attention in recent years. These nuclei provide a suitable laboratory for testing the residual interactions of the spherical shell model. Studies of N = 50, Z ∼ 40 nuclei, revealed that the low-lying states in these nuclei arise from proton excitations within the f 5/2 , p 3/2 , p 1/2 , and g 9/2 orbits. The higher angular momentum states were observed to have dominant contribution of 1p - 1h configurations involving a single g 9/2 neutron excitation across the N = 50 shell gap into the d 5/2 orbit. A comprehensive study of multiparticle-multihole (mp-mh) excitations in these nuclei may provide necessary insight into the evolution of shell structure above N = 50 shell gap. However, till date there is no experimental evidence of states involving two or more neutron excitations across the N = 50 shell gap in N = 50, Z ∼ 40 nuclei. The present work investigates high-spin states in the N = 50 nucleus, 91 Nb, with the purpose to search for states involving 2p - 2h excitations across the N = 50 shell closure

Near and sub-barrier fusion studies with radioactive nuclei: an overview

International Nuclear Information System (INIS)

Majumdar, Harashit

2004-01-01

Full text: Understanding of the reaction mechanism with radioactive nuclei, e.g., halo nuclei, at near barrier energies appears to be a challenging problem at present. Recent experimental and theoretical investigations of fusion of exotic nuclei with stable targets have yielded new insights into the structure of these nuclei and its effects on the fusion reaction dynamics. One interesting and intriguing result of this type of study is the controversy over fusion enhancement in the presence of strong break-up channels. Other novel information include an increase of break-up cross-sections and weakening or absence of threshold anomaly, related to energy dependence of optical model potentials, in the neighbourhood of the barrier. It is believed that the coupling of the entrance channel to different non-elastic channels (including break-up) is responsible for the above phenomena and these aspects are more prominent in the near barrier region. An overview of the experimental studies of fusion excitation function with RIB will be presented

Near and sub-barrier fusion studies with radioactive nuclei: an overview

International Nuclear Information System (INIS)

Majumdar, Harashit

2004-01-01

Full Text: Understanding of the reaction mechanism with radioactive nuclei, e.g., halo nuclei, at near barrier energies appears to be a challenging problem at present. Recent experimental and theoretical investigations of fusion of exotic nuclei with stable targets have yielded new insights into the structure of these nuclei and its effects on the fusion reaction dynamics. One interesting and intriguing result of this type of study is the controversy over fusion enhancement in the presence of strong break-up channels. Other novel information include an increase of break-up cross-sections and weakening or absence of threshold anomaly, related to energy dependence of optical model potentials, in the neighbourhood of the barrier. It is believed that the coupling of the entrance channel to different non-elastic channels (including break-up) is responsible for the above phenomena and these aspects are more prominent in the near barrier region. An overview of the experimental studies of fusion excitation function with RIB will be presented

Early history of experimental inertial confinement fusion and diagnostics in China

International Nuclear Information System (INIS)

Wang Chuanke; Jiang Shao'en; Ding Yongkun

2014-01-01

The early history of China's research on experimental laser inertial confinement fusion (ICF) and diagnostics technology is reviewed. The long and difficult path started from scratch, from learning the basics, looking up the literature and copying experiments, to independent research and development of comprehensive experimental facilities. This article fills a gap in the history of China's ICF experimental and diagnostics research. (authors)

Angular-momentum effects in subbarrier fusion

International Nuclear Information System (INIS)

Halbert, M.L.; Beene, J.R.

1993-01-01

It has been known since about 1980 that fusion of heavy ions is greatly enhanced below the Coulomb barrier compared with normal barrier-penetration expectations. The excitation function for fusion of 64 Ni + 100 Mo measured in collaboration with a group at Washington University shows the effect clearly. The barrier energy is about 142 MeV; the lowest point is at about 90% of the barrier energy. The dotted curve is the prediction of a one-dimensional-barrier-penetration calculation of a type that reproduces the fusion of light projectiles very well. Several theoretical approaches have been successful in explaining the enhancement seen in much of the excitation-function data, but it cannot be said that a full understanding of the physics is in hand even after more than a decade of hard work. In fact, the reasonable success of several rather different models shows that the underlying phenomena are not well understood. Other types of data might be helpful in distinguishing among the many different theoretical approaches. An important kind of information not measured in most of the experiments is the dependence on ell, the angular momentum of the fusing system. We obtained such information on the cross sections, σ ell, as a function of ell for the fusion of 64 Ni and 100 Mo using the Spin Spectrometer. This paper will first review the experimental method and data and then present results from a more sophisticated analysis of the same data

A new analysis procedure to extract fusion excitation function with large beam energy dispersions: application to the 6Li+120Sn and 7Li+119Sn

Directory of Open Access Journals (Sweden)

Di Pietro Alessia

2017-01-01

Full Text Available In the present paper it is described an analysis procedure suited for experiments where cross-sections strongly varying with energy are measured using beams having large energy dispersion. These cross-sections are typically the sub-barrier fusion excitation function of reactions induced by radioactive beams. The large beam energy dispersion, typical of these experiments, can lead to ambiguities in the association of the effective beam energy to the reaction product yields and consequently to an error in the determination of the excitation function. As a test case, the approach is applied to the experiments 6Li+120Sn and 7Li+119Sn measured in the energy range 14 MeV ≤ Ec.m. ≤28 MeV. The complete fusion cross sections are deduced from activation measurements using the stacked target technique. The results of these experiments, that employ the two weakly-bound stable Li isotopes, show that the complete fusion cross sections above the barrier are suppressed of about 70% and 85% with respect to the Universal Fusion Function, used as a standard reference, in the 6Li and 7Li induced reactions respectively. Moreover, the excitation functions of the two systems at energies below the barrier, do not show significant differences, despite the two systems have different n-transfer Qvalue.

Constraining statistical-model parameters using fusion and spallation reactions

Directory of Open Access Journals (Sweden)

Charity Robert J.

2011-10-01

Full Text Available The de-excitation of compound nuclei has been successfully described for several decades by means of statistical models. However, such models involve a large number of free parameters and ingredients that are often underconstrained by experimental data. We show how the degeneracy of the model ingredients can be partially lifted by studying different entrance channels for de-excitation, which populate different regions of the parameter space of the compound nucleus. Fusion reactions, in particular, play an important role in this strategy because they fix three out of four of the compound-nucleus parameters (mass, charge and total excitation energy. The present work focuses on fission and intermediate-mass-fragment emission cross sections. We prove how equivalent parameter sets for fusion-fission reactions can be resolved using another entrance channel, namely spallation reactions. Intermediate-mass-fragment emission can be constrained in a similar way. An interpretation of the best-fit IMF barriers in terms of the Wigner energies of the nascent fragments is discussed.

Multifrequency excitation of a clamped–clamped microbeam: Analytical and experimental investigation

KAUST Repository

Jaber, Nizar

2016-03-14

Using partial electrodes and a multifrequency electrical source, we present a large-bandwidth, large-amplitude clamped–clamped microbeam resonator excited near the higher order modes of vibration. We analytically and experimentally investigate the nonlinear dynamics of the microbeam under a two-source harmonic excitation. The first-frequency source is swept around the first three modes of vibration, whereas the second source frequency remains fixed. New additive and subtractive resonances are demonstrated. We illustrated that by properly tuning the frequency and amplitude of the excitation force, the frequency bandwidth of the resonator is controlled. The microbeam is fabricated using polyimide as a structural layer coated with nickel from the top and chromium and gold layers from the bottom. Using the Galerkin method, a reduced order model is derived to simulate the static and dynamic response of the device. A good agreement between the theoretical and experimental data are reported.

Multifrequency excitation of a clamped–clamped microbeam: Analytical and experimental investigation

KAUST Repository

Jaber, Nizar; Ramini, Abdallah; Younis, Mohammad I.

2016-01-01

Using partial electrodes and a multifrequency electrical source, we present a large-bandwidth, large-amplitude clamped–clamped microbeam resonator excited near the higher order modes of vibration. We analytically and experimentally investigate the nonlinear dynamics of the microbeam under a two-source harmonic excitation. The first-frequency source is swept around the first three modes of vibration, whereas the second source frequency remains fixed. New additive and subtractive resonances are demonstrated. We illustrated that by properly tuning the frequency and amplitude of the excitation force, the frequency bandwidth of the resonator is controlled. The microbeam is fabricated using polyimide as a structural layer coated with nickel from the top and chromium and gold layers from the bottom. Using the Galerkin method, a reduced order model is derived to simulate the static and dynamic response of the device. A good agreement between the theoretical and experimental data are reported.

Conceptual design of neutron diagnostic systems for fusion experimental reactor

International Nuclear Information System (INIS)

Iguchi, T.; Kaneko, J.; Nakazawa, M.

1994-01-01

Neutron measurement in fusion experimental reactors is very important for burning plasma diagnostics and control, monitoring of irradiation effects on device components, neutron source characterization for in-situ engineering tests, etc. A conceptual design of neutron diagnostic systems for an ITER-like fusion experimental reactor has been made, which consists of a neutron yield monitor, a neutron emission profile monitor and a 14-MeV spectrometer. Each of them is based on a unique idea to meet the required performances for full power conditions assumed at ITER operation. Micro-fission chambers of 235 U (and 238 U) placed at several poloidal angles near the first wall are adopted as a promising neutron yield monitor. A collimated long counter system using a 235 U fission chamber and graphite neutron moderators is also proposed to improve the calibration accuracy of absolute neutron yield determination

Conceptual design of fusion experimental reactor (FER)

International Nuclear Information System (INIS)

1984-03-01

A conceptual design study (option C) has been carried out for the fusion experimental reactor (FER). In addition to design of the tokamak reactor and associated systems based on the reference design specifications, feasibility of a water-shield reactor concept was examined as a topical study. The design study for the reference tokamak reactor has produced a reactor concept for the FER, along with major R D items for the concept, based on close examinations on thermal design, electromagnetics, neutronics and remote maintenance. Particular efforts have been directed to the area of electromagnetics. Detailed analyses with close simulation models have been performed on PF coil arrangements and configurations, shell effects of the blanket for plasma position unstability, feedback control, and eddy currents during disruptions. The major design specifications are as follows; Peak fusion power 437 MW Major radius 5.5 m Minor radius 1.1 m Plasma elongation 1.5 Plasma current 5.3 MA Toroidal beta 4 % Field on axis 5.7 T (author)

Thermally excited proton spin-flip laser emission in tokamaks

International Nuclear Information System (INIS)

Arunasalam, V.; Greene, G.J.

1993-07-01

Based on statistical thermodynamic fluctuation arguments, it is shown here for the first time that thermally excited spin-flip laser emission from the fusion product protons can occur in large tokamak devices that are entering the reactor regime of operation. Existing experimental data from TFTR supports this conjecture, in the sense that these measurements are in complete agreement with the predictions of the quasilinear theory of the spin-flip laser

Analysis of complete fusion excitation functions for 7Li+152Sm, 197Au and 209Bi reactions at around barrier energies

International Nuclear Information System (INIS)

Kharab, Rajesh; Chahal, Rajiv; Kumar, Rajiv

2017-01-01

In the present work we have analyzed the fusion excitation function for CF process using the simple Wong’s formula in conjunction with the energy dependent Woods-Saxon potential (EDWSP) in near barrier energy region for 7 Li+ 152 Sm, 197 Au and 209 Bi reactions

Complete and incomplete fusion measurement and analysis of excitation functions in sup 1 sup 2 C + sup 1 sup 2 sup 8 Te system at energies near and above the coulomb barrier

CERN Document Server

Sharma, M K; Prasad, R; Gupta, S; Musthafa, M M; Bhardwaj, H D; Sinha, A K

2003-01-01

In order to study complete and incomplete fusion in heavy ion induced reactions the experiment has been carried out for measuring excitation functions (EF's) for several reactions in the system sup 1 sup 2 C + sup 1 sup 2 sup 8 Te, in the energy range approx = 42 - 82 MeV, using activation technique. To the best of our knowledge EF's for presently measured reactions are being reported for the first time. The measured EF's have been compared with those calculated theoretically using codes CASCADE and ALICE-91. Effect of variation of parameters, of the codes, on calculated EF's has also been studied. The analysis of the present data indicates presence of contributions from incomplete fusion in some cases. In general, theoretical calculations agree well with the experimental data.

Pulsed excitation terahertz tomography - multiparametric approach

Science.gov (United States)

Lopato, Przemyslaw

2018-04-01

This article deals with pulsed excitation terahertz computed tomography (THz CT). Opposite to x-ray CT, where just a single value (pixel) is obtained, in case of pulsed THz CT the time signal is acquired for each position. Recorded waveform can be parametrized - many features carrying various information about examined structure can be calculated. Based on this, multiparametric reconstruction algorithm was proposed: inverse Radon transform based reconstruction is applied for each parameter and then fusion of results is utilized. Performance of the proposed imaging scheme was experimentally verified using dielectric phantoms.

Electrical insulation and conduction coating for fusion experimental devices

Energy Technology Data Exchange (ETDEWEB)

Onozuka, Masanori; Tsujimura, Seiji; Toyoda, Masahiko; Inoue, Masahiko [Mitsubishi Heavy Industries, Ltd., Yokohama (Japan); Abe, Tetsuya; Murakami, Yoshio [Japan Atomic Energy Research Inst., Naka (Japan)

1996-01-01

The development of electrical insulation and conduction coating methods that can be applied to large components of fusion experimental devices has been investigated. A thermal spraying method is used to coat the insulation or conduction materials on the structural components because of its applicability for large surfaces. The insulation material chosen was Al{sub 2}O{sub 3}, while Cr{sub 3}C{sub 2}-NiCr and WC-NiCr were chosen as conduction materials. These materials were coated on stainless steel substrates to examine the basic characteristics of the coated layers, such as their adhesive strength to the substrate, thermal shock resistance, electrical resistance, dielectric breakdown voltage, and thermal conductivity. It was found that they have sufficient electrical insulation and conduction properties, respectively. In addition, the sliding tests of the coated layers showed adequate frictional properties. The spraying method was tested on a 100- x 1000-mm surface and found to be applicable for large surfaces of experimental fusion devices. 9 refs., 6 figs., 15 tabs.

High power laser exciter accelerators

International Nuclear Information System (INIS)

Martin, T.H.

1975-01-01

Recent developments in untriggered oil and water switching now permit the construction of compact, high energy density pulsed power sources for laser excitation. These accelerators, developed principally for electron beam fusion studies, appear adaptable to laser excitation and will provide electron beams of 10 13 to 10 14 W in the next several years. The accelerators proposed for e-beam fusion essentially concentrate the available power from the outside edge of a disk into the central region where the electron beam is formed. One of the main problem areas, that of power flow at the vacuum diode insulator, is greatly alleviated by the multiplicity of electron beams that are allowable for laser excitation. A proposal is made whereby the disk-shaped pulsed power sections are stacked vertically to form a series of radially flowing electron beams to excite the laser gas volume. (auth)

Gross resonance-like structure of the complete fusion excitation function for the 16O + 28Si reaction

International Nuclear Information System (INIS)

Zheng Jiwen; Zheng Pingzi; Liu Guoxing

1993-01-01

The complete fusion excitation function for the 16 O + 28 Si reaction is measured in the incident energy range from 50 to 90 MeV with step of 1.0 MeV using a position sensitive ΔE-E telescope system. The striking gross resonance-like structure is observed when E c.m. c.m. 34.5, 38.5 and 43.0 MeV respectively. The structure vanishes gradually when E c.m. > 46.0 MeV

Conceptual design of fusion experimental reactor (FER)

International Nuclear Information System (INIS)

1984-02-01

This report describes the engineering conceptual design of Fusion Experimental Reactor (FER) which is to be built as a next generation tokamak machine. This design covers overall reactor systems including MHD equilibrium analysis, mechanical configuration of reactor, divertor, pumped limiter, first wall/breeding blanket/shield, toroidal field magnet, poloidal field magnet, cryostat, electromagnetic analysis, vacuum system, power handling and conversion, NBI, RF heating device, tritium system, neutronics, maintenance, cooling system and layout of facilities. The engineering comparison of a divertor with pumped limiters and safety analysis of reactor systems are also conducted. (author)

Subbarrier fusion in the systems 11,10Be+209Bi

International Nuclear Information System (INIS)

Signorini, C.; Yoshida, A.; Watanabe, Y.; Pierroutsakou, D.; Stroe, L.; Fukuda, T.; Mazzocco, M.; Fukuda, N.; Mizoi, Y.; Ishihara, M.; Sakurai, H.; Diaz-Torres, A.; Hagino, K.

2004-01-01

The subbarrier fusion cross sections with radioactive ion beams in the systems 10,11 Be+ 209 Bi have been measured and compared also with the stable system 9 Be+ 209 Bi. All three cross sections are similar within experimental accuracy; this is somehow unexpected since, in particular, the fusion process with 11 Be should be influenced by its halo structure and small binding energy and could behave in a different way from the other two Be isotopes, in particular from 10 Be, well bound. Extensive calculations were undertaken within the formalism of continuum discretized coupled channel (CDCC) that considered only the coupling to two-body breakup, into n+core, of the projectile with excitation to continuum up to 10 MeV. The results are in agreement with the 11,10 Be experimental data except at low energy where the cross sections could be influenced by target/projectile collective excitations. The CCFULL theoretical approach, compared to CDCC, seems to reproduce better the subbarrier region and worse the above barrier one. The 9 Be cross sections are all underestimated by the CDCC approach while are well reproduced by CCFULL calculations. This suggests that, in this last case, the schematization of the breakup process into 2 only fragments maybe is not adequate and/or other excitations, properly handed by the CCFULL code, could be relevant

Railgun pellet injection system for fusion experimental devices

International Nuclear Information System (INIS)

Onozuka, M.; Hasegawa, K.

1995-01-01

A railgun pellet injection system has been developed for fusion experimental devices. Using a low electric energy railgun system, hydrogen pellet acceleration tests have been conducted to investigate the application of the electromagnetic railgun system for high speed pellet injection into fusion plasmas. In the system, the pellet is pre-accelerated before railgun acceleration. A laser beam is used to induce plasma armature. The ignited plasma armature is accelerated by an electromagnetic force that accelerates the pellet. Under the same operational conditions, the energy conversion coefficient for the dummy pellets was around 0.4%, while that for the hydrogen pellets was around 0.12%. The highest hydrogen pellet velocity was 1.4 km s -1 using a 1 m long railgun. Based on the findings, it is estimated that the hydrogen pellet has the potential to be accelerated to 5 km s -1 using a 3 m long railgun. (orig.)

First preliminary design of an experimental fusion reactor

International Nuclear Information System (INIS)

1977-09-01

A preliminary design of a tokamak experimental fusion reactor to be built in the near future is under way. The goals of the reactor are to achieve reactor-level plasma conditions for a sufficiently long operation period and to obtain design, construction and operational experience for the main components of full-scale power reactors. This design covers overall reactor system including plasma characteristics, reactor structure, blanket neutronics, shielding, superconducting magnets, neutral beam injector, electric power supply system, fuel circulating system, reactor cooling system, tritium recovery system and maintenance scheme. The main design parameters are as follows: the reactor fusion power 100 MW, torus radius 6.75 m, plasma radius 1.5 m, first wall radius 1.75 m, toroidal magnet field on axis 6 T, blanket fertile material Li 2 O, coolant He, structural material 316SS and tritium breeding ratio 0.9. (auth.)

Tritium system design studies of fusion experimental breeder

International Nuclear Information System (INIS)

Deng Baiquan; Huang Jinhua

2003-01-01

A summary of the tritium system design studies for the engineering outline design of a fusion experimental breeder (FEB-E) is presented. This paper is divided into three sections. In first section, the geometry, loading features and tritium concentrations in liquid lithium of tritium breeding zones of blanket are described. The tritium flow chart corresponding to the tritium fuel cycle system has been constructed, and the inventories in ten subsystems are calculated using SWITRIM code in section 2. Results show that the necessary initial tritium storage to start up FEB-E with fusion power of 143 MW is about 319 g. In final section, the tritium leakage issues under different operation circumstances have been analyzed. It was found that the potential danger of tritium leakage could be resulted from the exhausted gas of the diverter system. It is important to elevate the tritium burnup fraction and reduce the tritium throughput. (authors)

Integrated assessment of thermal hydraulic processes in W7-X fusion experimental facility

Energy Technology Data Exchange (ETDEWEB)

Kaliatka, T., E-mail: tadas.kaliatka@lei.lt; Uspuras, E.; Kaliatka, A.

2017-02-15

Highlights: • The model of Ingress of Coolant Event experiment facility was developed using the RELAP5 code. • Calculation results were compared with Ingress of Coolant Event experiment data. • Using gained experience, the numerical model of Wendelstein 7-X facility was developed. • Performed analysis approved pressure increase protection system for LOCA event. - Abstract: Energy received from the nuclear fusion reaction is one of the most promising options for generating large amounts of carbon-free energy in the future. However, physical and technical problems existing in this technology are complicated. Several experimental nuclear fusion devices around the world have already been constructed, and several are under construction. However, the processes in the cooling system of the in-vessel components, vacuum vessel and pressure increase protection system of nuclear fusion devices are not widely studied. The largest amount of radioactive materials is concentrated in the vacuum vessel of the fusion device. Vacuum vessel is designed for the vacuum conditions inside the vessel. Rupture of the in-vessel components of the cooling system pipe may lead to a sharp pressure increase and possible damage of the vacuum vessel. To prevent the overpressure, the pressure increase protection system should be designed and implemented. Therefore, systematic and detailed experimental and numerical studies, regarding the thermal-hydraulic processes in cooling system, vacuum vessel and pressure increase protection system, are important and relevant. In this article, the numerical investigation of thermal-hydraulic processes in cooling systems of in-vessel components, vacuum vessels and pressure increase protection system of fusion devices is presented. Using the experience gained from the modelling of “Ingress of Coolant Event” experimental facilities, the numerical model of Wendelstein 7-X (W7-X) experimental fusion device was developed. The integrated analysis of the

Experimental and theoretical evidence for fluctuation driven activations in an excitable chemical system

Science.gov (United States)

Hastings, Harold; Sobel, Sabrina; Field, Richard; Minchenberg, Scott; Spinelli, Nicole; Zauderer, Keith

2011-03-01

An excitable medium is a system in which small perturbations die out, but sufficiently large perturbations generate large ``excitations.'' Biological examples include neurons and the heart; the latter supports waves of excitation normally generated by the sinus node, but occasionally generated by other mechanisms. The ferroin-catalyzed Belousov-Zhabotinsky reaction is the prototype chemical excitable medium. We present experimental and theoretical evidence for that random fluctuations can generate excitations in the Belousov-Zhabothinsky reaction. Although the heart is significantly different, there are some scaling analogies. This material is based upon work supported by the Department of Energy under Award Number DE-FG02-08ER64623.

Higher order modes excitation of electrostatically actuated clamped–clamped microbeams: experimental and analytical investigation

KAUST Repository

Jaber, Nizar

2016-01-06

© 2016 IOP Publishing Ltd. In this study, we demonstrate analytically and experimentally the excitations of the higher order modes of vibrations in electrostatically actuated clamped-clamped microbeam resonators. The concept is based on using partial electrodes with shapes that induce strong excitation of the mode of interest. The devices are fabricated using polyimide as a structural layer coated with nickel from the top and chrome and gold layers from the bottom. Experimentally, frequency sweeps with different electro-dynamical loading conditions are shown to demonstrate the excitation of the higher order modes of vibration. Using a half electrode, the second mode is excited with high amplitude of vibration compared with almost zero response using the full electrode. Also, using a two-third electrode configuration is shown to amplify the third mode resonance amplitude compared with the full electrode under the same electrical loading conditions. An analytical model is developed based on the Euler-Bernollui beam model and the Galerkin method to simulate the device response. Good agreement between the simulation results and the experimental data is reported.

8th International School of Fusion Reactor Technology "Ettore Majorana"

CERN Document Server

Leotta, G G; Muon-catalyzed fusion and fusion with polarized nuclei

1988-01-01

The International School of Fusion Reactor Technology started its courses 15 years ago and since then has mantained a biennial pace. Generally, each course has developed the subject which was announced in advance at the closing of the previous course. The subject to which the present proceedings refer was chosen in violation of that rule so as to satisfy the recent and diffuse interest in cold fusion among the main European laboratories involved in controlled thermonuclear research (CTR). In the second half of 1986 we started to prepare a workshop aimed at assessing the state of the art and possibly of the perspectives of muon- catalyzed fusion. Research in this field has recently produced exciting experimental results open to important practical applications. We thought it worthwhile to consider also the beneficial effects and problems of the polarization ofthe nuclei in both cold and thermonuclear fusion. In preparing the 8th Course on Fusion Reactor Technology, it was necessary to abandon the tradi...

Interpretation of the nonlinear mode excitation in the ITER gyrotron

International Nuclear Information System (INIS)

Nusinovich, G. S.; Sinitsyn, O. V.

2007-01-01

This study was motivated by an interesting physical effect observed in experiments with a 1 MW, 170 GHz, continuous-wave gyrotron developed at the Japan Atomic Energy Agency for plasma heating and current drive in ITER [see, e.g., Fusion Eng. Des. 55, issues 2-3 (2001)]. In these experiments, the gyrotron switching from a parasitic mode to the operating one was observed with the increase in external magnetic field in the region of hard self-excitation of the operating mode where it cannot be excited from the noise level in the absence of other modes. Below, the theory describing this effect is developed. The switching mechanism caused by merging and disappearance of two (one stable and another unstable) equilibrium states with nonzero amplitudes of both modes is proposed. It is found that the present theory can correctly interpret experimental results qualitatively, but the lack of experimental data does not let the authors carry out some simulations more adequate to experimental conditions

Excitation cross sections for Li3+, Ne10+ and Ar18++H(1s) collisions of interest in fusion plasma diagnostics

International Nuclear Information System (INIS)

Suarez, J; Errea, L F; Guzman, F; Pons, B

2013-01-01

We have calculated state-selective excitation cross sections in fully stripped Li 3+ , Ne 10+ and Ar 18+ +H(1s) collisions from low (1 keV/amu) to high (1000 keV/amu) impact energies, relevant in fusion plasma diagnostics. In order to cover this broad impact energy range, three different theoretical methods have been employed: the semi-classical molecular and one-centre atomic-orbital close-coupling approaches, and the classical trajectory Monte Carlo method. Recommended partial excitation cross sections are provided by merging the results obtained with each method in the energy range where they are the most accurate. (paper)

Investigation of incomplete fusion dynamics by measurement of excitation functions in the 20Ne + 59Co system

International Nuclear Information System (INIS)

Singh, D.; Linda, Sneha Bharti; Giri, Pankaj K.; Singh, Smita Shree; Kumar, Harish; Afzal Ansari, M.; Ali, Rahbar; Rashid, M.H.; Guin, R.; Das, S.K.

2015-01-01

In the present work, an attempt has been made to address some important aspects of CF and ICF dynamics for the system 20 Ne + 59 Co in the projectile energy range ≈ 62–150 MeV by using recoil catcher activation technique with the following off-line γ-ray spectroscopy. Excitation Functions (EFs) for the following reactions: 59 Co(Ne, α p4n) 70 Ga, 59 Co(Ne, 3αp3n) 63 Zn, 59 Co (Ne, 3αp4n) 62 Zn and 59 Co (Ne, 4α3n) 60 Cu have been measured. No precursor decay contribution has been observed for these measured evaporation residues. The measured values of total fusion cross-sections of the above evaporation residues have been compared with the theoretical total complete fusion cross sections calculated by code PACE-2, which do not take into account ICF contribution

Railgun pellet injection system for fusion experimental devices

Energy Technology Data Exchange (ETDEWEB)

Onozuka, M. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan). Adv. Tech. Dev. Dept.; Oda, Y. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan). Adv. Tech. Dev. Dept.; Azuma, K. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan). Adv. Tech. Dev. Dept.; Satake, K. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan). Adv. Tech. Dev. Dept.; Kasai, S. [Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun 319-11 (Japan); Hasegawa, K. [Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun 319-11 (Japan)

1995-11-01

A railgun pellet injection system has been developed for fusion experimental devices. Using a low electric energy railgun system, hydrogen pellet acceleration tests have been conducted to investigate the application of the electromagnetic railgun system for high speed pellet injection into fusion plasmas. In the system, the pellet is pre-accelerated before railgun acceleration. A laser beam is used to induce plasma armature. The ignited plasma armature is accelerated by an electromagnetic force that accelerates the pellet. Under the same operational conditions, the energy conversion coefficient for the dummy pellets was around 0.4%, while that for the hydrogen pellets was around 0.12%. The highest hydrogen pellet velocity was 1.4 km s{sup -1} using a 1 m long railgun. Based on the findings, it is estimated that the hydrogen pellet has the potential to be accelerated to 5 km s{sup -1} using a 3 m long railgun. (orig.).

Determination of atomic data pertinent to the Magnetic Fusion Program: Technical progress report, 15 May 1986-30 September 1987

International Nuclear Information System (INIS)

Wiese, W.L.

1987-01-01

Dielectronic recombination and excitation rates, electron-impact excitation and ionization cross sections, and wavelengths and energy levels of prominent spectral lines are experimentally and theoretically determined. Wavelengths for both electric and magnetic dipole transitions and atomic energy level data are also critically evaluated, compiled, and tabulated. Theoretical methods use both relativistic and nonrelativistic formulations. The work concentrated on ions of materials commonly used in current fusion devices, such as titanium, iron, and nickel, as well as heavier elements expected to be introduced into next-generation fusion devices for diagnostic purposes, such as krypton and xenon. The range of ions is extended to include very highly charged species in anticipation of needs in very high-temperature fusion devices such as TFTR and its successors. Work described also represents collaboration with major fusion laboratories such as Oak Ridge National Laboratory, Princeton Plasma Physics Laboratory, and GA Technologies

Nuclear dynamics around the barrier: from fusion to evaporation

International Nuclear Information System (INIS)

Simenel, Cedric

2003-01-01

This work is devoted to aspects of nuclear dynamics around the barrier. It is shown that for fusion reactions, the Coulomb field couples relative motion of nuclei to rotation of a deformed projectile independently of the energy and the charge of the nuclei. An experimental study of the reaction 6 He + 190 Os via gamma spectroscopy of product nuclei has shown that the break up of the 6 He is coupled to the relative motion too, a strong hindrance resulting in the fusion around and above the fusion barrier. The path to fusion after overcoming the barrier, especially the charge equilibration, have been studied in the framework of the TDHF theory via the preequilibrium GDR excited in N/Z asymmetric reactions. An application to formation of the super-heavy elements has been proposed. Finally, couplings between protons and neutrons have been shown up in mean field calculations. Their main expected effect is an emission of protons under the Coulomb barrier. (author)

Experimental determination of fragment excitation energies in multifragmentation events

Energy Technology Data Exchange (ETDEWEB)

Marie, N.; Natowitz, J.B. [Texas A and M Univ., College Station, TX (United States). Cyclotron Inst.; Chbihi, A.; Le Fevre, A.; Salou, S.; Wieleczko, J.P.; Gingras, L.; Auger, G. [Grand Accelerateur National d`Ions Lourds, 14 - Caen (France); Assenard, M. [Nantes Univ., 44 (France); Bacri, Ch.O. [Centre National de la Recherche Scientifique, CNRS, 91 - Orsay (France)] [and others

1998-03-17

For 50 MeV/nucleon {sup 129}Xe + {sup nat}Sn multifragmentation events, by means of correlation techniques, the multiplicities of the hydrogen and helium isotopes which were emitted by the hot primary excited fragments produced at the stage of the disassembly of an equilibrated hot source are determined. The relative kinetic energy distributions between the primary clusters and the light charged particles that they evaporate are also derived. From the comparison between the secondary multiplicities observed experimentally and the multiplicities predicted by the GEMINI model, it is concluded that the source breaks into primary fragments which are characterized by the same N/Z ratio as the combined system. Knowing the secondary light charged particle multiplicities and kinetic energies, the average charges of the hot fragments and are reconstructed their mean excitation energies are estimated. The fragment excitation energies are equal to 3.0 MeV/nucleon for the full range of intermediate mass fragment atomic number. This global constancy indicates that, on the average, thermodynamical equilibrium was achieved at the disassembly stage of the source. (author) 25 refs.

Experimental determination of fragment excitation energies in multifragmentation events

International Nuclear Information System (INIS)

Marie, N.; Natowitz, J.B.; Assenard, M.; Bacri, Ch.O.

1998-01-01

For 50 MeV/nucleon 129 Xe + nat Sn multifragmentation events, by means of correlation techniques, the multiplicities of the hydrogen and helium isotopes which were emitted by the hot primary excited fragments produced at the stage of the disassembly of an equilibrated hot source are determined. The relative kinetic energy distributions between the primary clusters and the light charged particles that they evaporate are also derived. From the comparison between the secondary multiplicities observed experimentally and the multiplicities predicted by the GEMINI model, it is concluded that the source breaks into primary fragments which are characterized by the same N/Z ratio as the combined system. Knowing the secondary light charged particle multiplicities and kinetic energies, the average charges of the hot fragments and are reconstructed their mean excitation energies are estimated. The fragment excitation energies are equal to 3.0 MeV/nucleon for the full range of intermediate mass fragment atomic number. This global constancy indicates that, on the average, thermodynamical equilibrium was achieved at the disassembly stage of the source. (author)

Alpha particle emission as a probe of the level density in highly excited A∼200 nuclei

International Nuclear Information System (INIS)

Fabris, D.; Fioretto, E.; Viesti, G.; Cinausero, M.; Gelli, N.; Hagel, K.; Lucarelli, F.; Natowitz, J.B.; Nebbia, G.; Prete, G.; Wada, R.

1994-01-01

The alpha particle emission from 90 to 140 MeV 19 F+ 181 Ta fusion-evaporation reactions has been studied. The comparisons of the experimental spectral shapes and multiplicities with statistical model predictions indicate a need to use an excitation energy dependent level-density parameter a=A/K in which K increases with excitation energy. This increase is more rapid than that in lower mass nuclei. The effect of this change in level density on the prescission multiplicities in fission is significant

Effect of the adiabatic vibrational coupling on the fusion of the 16O-238U interaction

International Nuclear Information System (INIS)

Ismail, M.; Osman, M.; Ramadan, Kh.A.; Seif, W.

2003-01-01

The effect of both rotation and vibration of a deformed target nucleus on the fusion cross-section and barrier distributions was studied. This was done in the framework of the microscopically derived heavy-ion (HI) potential. Moreover, the effect of target deformation up to β 6 and the density dependence of the NN force on the fusion process was studied in the presence of vibrational excitations of the target. The results obtained were compared with experimental data. (author)

In-complete fusion of 16O with 159Tb: measurement and analysis of excitation functions

International Nuclear Information System (INIS)

Singh, Pushpendra P.; Unnati; Sharma, Manoj Kumar; Singh, B.P.; Prasad, R.; Rakesh Kumar; Golda, K.S.; Bhardwaj, H.D.

2006-01-01

In order to have better understanding of incomplete fusion reaction dynamics, more experimental data covering a wide range of periodic table and energy are required. Cross-section data of such products are also in demand to determine the optimum irradiation conditions for the production of radioactive ion beams

Development of electrical insulation and conduction coating for fusion experimental devices

Energy Technology Data Exchange (ETDEWEB)

Onozuka, M. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan); Tsujimura, S. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan); Toyoda, M. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan); Inoue, M. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan); Abe, T. [Japan Atomic Energy Research Inst., Naka (Japan); Murakami, Y. [Japan Atomic Energy Research Inst., Naka (Japan)

1995-12-31

Development of electrical insulation and conduction methods that can be applied for large components have been investigated for future large fusion experimental devices. A thermal spraying method is employed to coat the insulation or conduction materials on the structural components. Al{sub 2}O{sub 3} has been selected as an insulation material, while Cr{sub 3}C{sub 2}-NiCr and WC-NiCr have been chosen as conduction materials. These materials were coated on stainless steel base plates to examine the basic characteristics of the coated layers, such as their adhesive strength to the base plate and electrical resistance. It was found that they have sufficient electrical insulation and conduction properties, respectively. In addition, the sliding tests of the coated layers showed sufficient frictional properties. The applicability of the spraying method was examined on a 100mm x 1000mm surface and found to be applicable for large surfaces in fusion experimental devices. (orig.).

Development of electrical insulation and conduction coating for fusion experimental devices

International Nuclear Information System (INIS)

Onozuka, M.; Tsujimura, S.; Toyoda, M.; Inoue, M.; Abe, T.; Murakami, Y.

1995-01-01

Development of electrical insulation and conduction methods that can be applied for large components have been investigated for future large fusion experimental devices. A thermal spraying method is employed to coat the insulation or conduction materials on the structural components. Al 2 O 3 has been selected as an insulation material, while Cr 3 C 2 -NiCr and WC-NiCr have been chosen as conduction materials. These materials were coated on stainless steel base plates to examine the basic characteristics of the coated layers, such as their adhesive strength to the base plate and electrical resistance. It was found that they have sufficient electrical insulation and conduction properties, respectively. In addition, the sliding tests of the coated layers showed sufficient frictional properties. The applicability of the spraying method was examined on a 100mm x 1000mm surface and found to be applicable for large surfaces in fusion experimental devices. (orig.)

Neutron spectrometer for DD/DT burning ratio measurement in fusion experimental reactor

International Nuclear Information System (INIS)

Asai, Keisuke; Naoi, Norihiro; Iguchi, Tetsuo; Watanabe, Kenichi; Kawarabayashi, Jun; Nishitani, Takeo

2006-01-01

The most feasible fuels for a fusion reactor are D (Deuterium) and T (Tritium). DD and/or DT fusion reaction or nuclear burning reaction provides two kinds of neutrons, DD neutron and DT neutron, respectively. DD/DT burning ratio, which can be estimated by DD/DT neutron ratio in the burning plasma, is essential for burn control, alpha particle emission rate monitoring and tritium fuel cycle estimation. Here we propose a new neutron spectrometer for the absolute DD/DT burning ratio measurement. The system consists of a Proton Recoil Telescope (PRT) and a Time-of-Flight (TOF) technique. We have conducted preliminary experiments with a prototype detector and a DT neutron beam (φ20 mm) at the Fusion Neutronics Source, Japan Atomic Energy Agency (JAEA), to assess its basic performance. The detection efficiency obtained by the experiment is consistent with the calculation results in PRT, and sufficient energy resolution for the DD/DT neutron discrimination has been achieved in PRT and TOF. The validity of the Monte Carlo calculation has also been confirmed by comparing the experimental results with the calculation results. The design consideration of this system for use in ITER (International Thermonuclear Experimental Reactor) has shown that this system is capable of monitoring the line-integrated DD/DT burning ratio for the plasma core line of sight with the required measurement accuracy of 20% in the upper 4 decades of the ITER operation (fusion power: 100 kW-700 MW). (author)

Analytical and experimental study of two delay-coupled excitable units.

Science.gov (United States)

Weicker, Lionel; Erneux, Thomas; Keuninckx, Lars; Danckaert, Jan

2014-01-01

We investigate the onset of time-periodic oscillations for a system of two identical delay-coupled excitable (nonoscillatory) units. We first analyze these solutions by using asymptotic methods. The oscillations are described as relaxation oscillations exhibiting successive slow and fast changes. The analysis highlights the determinant role of the delay during the fast transition layers. We then study experimentally a system of two coupled electronic circuits that is modeled mathematically by the same delay differential equations. We obtain quantitative agreements between analytical and experimental bifurcation diagrams.

Atomic and molecular physics of controlled thermonuclear fusion

International Nuclear Information System (INIS)

Joachain, C.J.; Post, D.E.

1983-01-01

This book attempts to provide a comprehensive introduction to the atomic and molecular physics of controlled thermonuclear fusion, and also a self-contained source from which to start a systematic study of the field. Presents an overview of fusion energy research, general principles of magnetic confinement, and general principles of inertial confinement. Discusses the calculation and measurement of atomic and molecular processes relevant to fusion, and the atomic and molecular physics of controlled thermonuclear research devices. Topics include recent progress in theoretical methods for atomic collisions; current theoretical techniques for electron-atom and electronion scattering; experimental aspects of electron impact ionization and excitation of positive ions; the theory of charge exchange and ionization by heavy particles; experiments on electron capture and ionization by multiply charged ions; Rydberg states; atomic and molecular processes in high temperature, low-density magnetically confined plasmas; atomic processes in high-density plasmas; the plasma boundary region and the role of atomic and molecular processes; neutral particle beam production and injection; spectroscopic plasma diagnostics; and particle diagnostics for magnetic fusion experiments

Effect of dissipation on dynamical fusion thresholds

International Nuclear Information System (INIS)

Sierk, A.J.

1986-01-01

The existence of dynamical thresholds to fusion in heavy nuclei (A greater than or equal to 200) due to the nature of the potential-energy surface is shown. These thresholds exist even in the absence of dissipative forces, due to the coupling between the various collective deformation degrees of freedom. Using a macroscopic model of nuclear shape dynamics, It is shown how three different suggested dissipation mechanisms increase by varying amounts the excitation energy over the one-dimensional barrier required to cause compound-nucleus formation. The recently introduced surface-plus-window dissipation may give a reasonable representation of experimental data on fusion thresholds, in addition to properly describing fission-fragment kinetic energies and isoscalar giant multipole widths. Scaling of threshold results to asymmetric systems is discussed. 48 refs., 10 figs

Fusion below the Coulomb barrier (I); Fusion abajo de la barrera coulombiana (I)

Energy Technology Data Exchange (ETDEWEB)

Aguilera R, E.F.; Vega C, J.J.; Murillo, G.; Kolata, J.J. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

1987-02-15

Absolute normalization factors for fusion sections are determined with good precision by means of a system of four monitors that it measure Rutherford scattering. An excitation function for fusion of the system {sup 37}Cl + {sup 55}Ni, which presents the prospective behavior based on the one existent systematic is obtained. (Author)

Some fusion perspectives

International Nuclear Information System (INIS)

McNally, J.R. Jr.

1977-01-01

Some of the concepts of nuclear fusion reactions, advanced fusion fuels, environmental impacts, etc., are explored using the following general outline: I. Principles of Fusion (Nuclear Fuels and Reactions, Lawson Condition, n tau vs T, Nuclear Burn Characteristics); II. Magnetic Mirror Possibilities (the Ion Layer and Electron Layer, Exponential Build-up at MeV energies, Lorentz trapping at GeV energies); III. Pellet Fuel Fusion Prospects (Advanced Pellet Fuel Fusion Prospects, Burn Characteristics and Applications, Excitation-heating Prospects for Runaway Ion Temperatures). Inasmuch as the outline is very skeletal, a significant research and development effort may be in order to evaluate these prospects in more detail and hopefully ''harness the H-bomb'' for peaceful applications, the author concludes. 28 references

Conceptual design study of fusion experimental reactor (FER)

International Nuclear Information System (INIS)

1986-11-01

Since 1980 the design study has been conducted at JAERI for the Fusion Experimental Reactor (FER) which has been proposed to be the next machine to JT-60 in the Japanese long term program of fusion reactor development. During two years from 1984 to 1985 FER concept was reviewed and redesigned. This report is the summary of the results obtained in the review and redesign activities in 1984 and 85. In the first year FER concept was discussed again and its frame work was reestablished. According to the new frame work the major reactor components of FER were designed. In the second year the whole plant system design including plant layout plan was conducted as well as the more detailed design analysis of the reactor conponents. The newly established frame for FER design is as follows: 1) Plasma : Self-ignition. 2) Operation scenario : Quasi-steady state operation with long burn pulse. 3) Neutron fluence on the first wall : 0.3 MWY/M 2 . 4) Blanket : Non-tritium breeding blanket with test modules for breeding blanket development. 5) Magnets : Superconducting Magnets. (author)

Structure information from fusion barriers

Indian Academy of Sciences (India)

Pb, using the coupled reaction channel (CRC) method and correct structure information, have been analysed. The barrier distributions derived from these excitation functions including many of the significant channels are featureless, although these channels have considerable effects on the fusion excitation function.

Effect of projectile on incomplete fusion reactions at low energies

Directory of Open Access Journals (Sweden)

Sharma Vijay R.

2017-01-01

Full Text Available Present work deals with the experimental studies of incomplete fusion reaction dynamics at energies as low as ≈ 4 - 7 MeV/A. Excitation functions populated via complete fusion and/or incomplete fusion processes in 12C+175Lu, and 13C+169Tm systems have been measured within the framework of PACE4 code. Data of excitation function measurements on comparison with different projectile-target combinations suggest the existence of ICF even at slightly above barrier energies where complete fusion (CF is supposed to be the sole contributor, and further demonstrates strong projectile structure dependence of ICF. The incomplete fusion strength functions for 12C+175Lu, and 13C+169Tm systems are analyzed as a function of various physical parameters at a constant vrel ≈ 0.053c. It has been found that one neutron (1n excess projectile 13C (as compared to 12C results in less incomplete fusion contribution due to its relatively large negative α-Q-value, hence, α Q-value seems to be a reliable parameter to understand the ICF dynamics at low energies. In order to explore the reaction modes on the basis of their entry state spin population, the spin distribution of residues populated via CF and/or ICF in 16O+159Tb system has been done using particle-γ coincidence technique. CF-α and ICF-α channels have been identified from backward (B and forward (F α-gated γspectra, respectively. Reaction dependent decay patterns have been observed in different α emitting channels. The CF channels are found to be fed over a broad spin range, however, ICF-α channels was observed only for high-spin states. Further, the existence of incomplete fusion at low bombarding energies indicates the possibility to populate high spin states

Effect of projectile on incomplete fusion reactions at low energies

Science.gov (United States)

Sharma, Vijay R.; Shuaib, Mohd.; Yadav, Abhishek; Singh, Pushpendra P.; Sharma, Manoj K.; Kumar, R.; Singh, Devendra P.; Singh, B. P.; Muralithar, S.; Singh, R. P.; Bhowmik, R. K.; Prasad, R.

2017-11-01

Present work deals with the experimental studies of incomplete fusion reaction dynamics at energies as low as ≈ 4 - 7 MeV/A. Excitation functions populated via complete fusion and/or incomplete fusion processes in 12C+175Lu, and 13C+169Tm systems have been measured within the framework of PACE4 code. Data of excitation function measurements on comparison with different projectile-target combinations suggest the existence of ICF even at slightly above barrier energies where complete fusion (CF) is supposed to be the sole contributor, and further demonstrates strong projectile structure dependence of ICF. The incomplete fusion strength functions for 12C+175Lu, and 13C+169Tm systems are analyzed as a function of various physical parameters at a constant vrel ≈ 0.053c. It has been found that one neutron (1n) excess projectile 13C (as compared to 12C) results in less incomplete fusion contribution due to its relatively large negative α-Q-value, hence, α Q-value seems to be a reliable parameter to understand the ICF dynamics at low energies. In order to explore the reaction modes on the basis of their entry state spin population, the spin distribution of residues populated via CF and/or ICF in 16O+159Tb system has been done using particle-γ coincidence technique. CF-α and ICF-α channels have been identified from backward (B) and forward (F) α-gated γspectra, respectively. Reaction dependent decay patterns have been observed in different α emitting channels. The CF channels are found to be fed over a broad spin range, however, ICF-α channels was observed only for high-spin states. Further, the existence of incomplete fusion at low bombarding energies indicates the possibility to populate high spin states

Quantitative analysis of the fusion cross sections using different microscopic nucleus-nucleus interactions

Energy Technology Data Exchange (ETDEWEB)

Adel, A. [Cairo University, Physics Department, Faculty of Science, Giza (Egypt); Majmaah University, Physics Department, College of Science, Al-Zulfi (Saudi Arabia); Alharbi, T. [Majmaah University, Physics Department, College of Science, Al-Zulfi (Saudi Arabia)

2017-01-15

The fusion cross sections for reactions involving medium and heavy nucleus-nucleus systems are investigated near and above the Coulomb barrier using the one-dimensional barrier penetration model. The microscopic nuclear interaction potential is computed by four methods, namely: the double-folding model based on a realistic density-dependent M3Y NN interaction with a finite-range exchange part, the Skyrme energy density functional in the semiclassical extended Thomas-Fermi approximation, the generalized Proximity potential, and the Akyuez-Winther interaction. The comparison between the calculated and the measured values of the fusion excitation functions indicates that the calculations of the DFM give quite satisfactory agreement with the experimental data, being much better than the other methods. New parameterized forms for the fusion barrier heights and positions are presented. Furthermore, the effects of deformation and orientation degrees of freedom on the distribution of the Coulomb barrier characteristics as well as the fusion cross sections are studied for the reactions {sup 16}O + {sup 70}Ge and {sup 28}Si + {sup 100}Mo. The calculated values of the total fusion cross sections are compared with coupled channel calculations using the code CCFULL and compared with the experimental data. Our results reveal that the inclusion of deformations and orientation degrees of freedom improves the comparison with the experimental data. (orig.)

Nuclear structure and heavy-ion fusion

International Nuclear Information System (INIS)

Stokstad, R.G.

1980-10-01

A series of lectures is presented on experimental studies of heavy-ion fusion reactions with emphasis on the role of nuclear structure in the fusion mechanism. The experiments considered are of three types: the fusion of lighter heavy ions at subcoulomb energies is studied with in-beam γ-ray techniques; the subbarrier fusion of 16 O and 40 Ar with the isotopes of samarium is detected out of beam by x-radiation from delayed activity; and measurements at very high energies, again for the lighter ions, employ direct particle identification of evaporation residues. The experimental data are compared with predictions based on the fusion of two spheres with the only degree of freedom being the separation of the centers, and which interact via potentials that vary smoothly with changes in the mass and charge of the projectile and target. The data exhibit with the isotopes of samarium, a portion of these deviations can be understood in terms of the changing deformation of the target nucleus, but an additional degree of freedom such as neck formation appears necessary. The results on 10 B + 16 O and 12 C + 14 N → 26 Al at high bombarding energies indicate a maximum limiting angular momentum characteristic of the compound nucleus. At lower energies the nuclear structure of the colliding ion seems to affect strongly the cross section for fusion. Measurements made at subbarrier energies for a variety of projectile-target combinations in the 1p and 2s - 1d shell also indicate that the valence nucleons can affect the energy dependence for fusion. About half the systems studied so far have structureless excitation functions which follow a standard prediction. The other half exhibit large variations from this prediction. The possible importance of neutron transfer is discussed. The two-center shell model appears as a promising approach for gaining a qualitative understanding of these phenomena. 95 references, 52 figures, 1 table

KEWPIE2: A cascade code for the study of dynamical decay of excited nuclei

Science.gov (United States)

Lü, Hongliang; Marchix, Anthony; Abe, Yasuhisa; Boilley, David

2016-03-01

KEWPIE-a cascade code devoted to investigating the dynamical decay of excited nuclei, specially designed for treating very low probability events related to the synthesis of super-heavy nuclei formed in fusion-evaporation reactions-has been improved and rewritten in C++ programming language to become KEWPIE2. The current version of the code comprises various nuclear models concerning the light-particle emission, fission process and statistical properties of excited nuclei. General features of the code, such as the numerical scheme and the main physical ingredients, are described in detail. Some typical calculations having been performed in the present paper clearly show that theoretical predictions are generally in accordance with experimental data. Furthermore, since the values of some input parameters cannot be determined neither theoretically nor experimentally, a sensibility analysis is presented. To this end, we systematically investigate the effects of using different parameter values and reaction models on the final results. As expected, in the case of heavy nuclei, the fission process has the most crucial role to play in theoretical predictions. This work would be essential for numerical modeling of fusion-evaporation reactions.

Modeling an Excitable Biosynthetic Tissue with Inherent Variability for Paired Computational-Experimental Studies.

Directory of Open Access Journals (Sweden)

Tanmay A Gokhale

2017-01-01

Full Text Available To understand how excitable tissues give rise to arrhythmias, it is crucially necessary to understand the electrical dynamics of cells in the context of their environment. Multicellular monolayer cultures have proven useful for investigating arrhythmias and other conduction anomalies, and because of their relatively simple structure, these constructs lend themselves to paired computational studies that often help elucidate mechanisms of the observed behavior. However, tissue cultures of cardiomyocyte monolayers currently require the use of neonatal cells with ionic properties that change rapidly during development and have thus been poorly characterized and modeled to date. Recently, Kirkton and Bursac demonstrated the ability to create biosynthetic excitable tissues from genetically engineered and immortalized HEK293 cells with well-characterized electrical properties and the ability to propagate action potentials. In this study, we developed and validated a computational model of these excitable HEK293 cells (called "Ex293" cells using existing electrophysiological data and a genetic search algorithm. In order to reproduce not only the mean but also the variability of experimental observations, we examined what sources of variation were required in the computational model. Random cell-to-cell and inter-monolayer variation in both ionic conductances and tissue conductivity was necessary to explain the experimentally observed variability in action potential shape and macroscopic conduction, and the spatial organization of cell-to-cell conductance variation was found to not impact macroscopic behavior; the resulting model accurately reproduces both normal and drug-modified conduction behavior. The development of a computational Ex293 cell and tissue model provides a novel framework to perform paired computational-experimental studies to study normal and abnormal conduction in multidimensional excitable tissue, and the methodology of modeling

Fission times of excited nuclei: An experimental overview

International Nuclear Information System (INIS)

Morjean, M.; Morjean, M.; Jacquet, D.

2009-01-01

An overview of selected recent experimental results on fission times is presented. Evidences for over-damped motion up to saddle point during the fission process of highly excited nuclei have been obtained independently through fission probability, pre-scission multiplicity and direct time measurements. In addition, strong clues have been found for a temperature dependency of friction. Experiments probing transient effects through fission probabilities are presented and the counterbalanced effects of friction and level density parameters are discussed. Promising perspectives for super-heavy stability studies, based on fission time measurements, are presented. (authors)

Nuclear structure and fusion at the barrier

International Nuclear Information System (INIS)

Reisdorf, W.

1985-01-01

A comparative study of measured fusion excitation functions in the vicinity of the barrier reveals nuclear structure effects, due in particular to the coupling of the fusion process to direct-reaction channels. (orig.)

Parametric and alternative studies for fusion experimental reactor (FER) (FY 1984)

International Nuclear Information System (INIS)

1986-01-01

Since 1980 the design study has been conducted at JAERI for the Fusion Experimental Reactor (FER) which has been proposed to be the next machine to JT-60 in the Japanese long term program of fusion reactor development. Starting from 1984 FER design is being reviewed and redesigned. This report is a part of the interim report which describes the results obtained in the review and redesign activities in FY 1984. This report includes the following parametric and alternative studies for the FER reference design: 1) parametric studies concerning with core plasma magnets, and operation scenario and power supply, 2) tritium breeding blanket, 3) the study for the steady state operation FER, 4) OTHERS. (AUTHOR)

The international thermonuclear experimental reactor and the future of nuclear fusion energy

International Nuclear Information System (INIS)

Pan Chuanhong

2010-01-01

Energy shortage and environmental problems are now the two largest challenges for human beings. Magnetic confinement nuclear fusion, which has achieved great progress since the 1990's, is anticipated to be a way to realize an ideal source of energy in the future because of its abundance, environmental compatibility, and zero carbon release. Exemplified by the construction of the International Thermonuclear Experimental Reactor (ITER), the development of nuclear fusion energy is now in its engineering phase, and should be realized by the middle of this century if all objectives of the ITER project are met. (author)

Some manufacture and installation problems in experimental assemblies for fusion research

International Nuclear Information System (INIS)

Partridge, J.E.; Rappe, G.; Hoare, F.; McDonald, J.

1976-01-01

Many of the manufacturing problems encountered when developing specialised items of fusion apparatus are only solved after much experimentation and a good deal of trial and error. After the experiment is built such problems may be forgotten and are often not recorded so that subsequent workers in the same field may start with no past experience on which to build. The paper therefore highlights some of the manufacturing problems which have been solved during the construction of some of the experimental apparatus at Culham

Study of Cold Fusion Reactions Using Collective Clusterization Approach

Science.gov (United States)

Kaur, Gurjit; Sandhu, Kirandeep; Sharma, Manoj K.

2017-10-01

Within the framework of the dynamical cluster decay model (DCM), the 1n evaporation cross-sections ({σ }1n) of cold fusion reactions (Pb and Bi targets) are calculated for {Z}{CN}=104-113 superheavy nuclei. The calculations are carried out in the fixed range of excitation energy {E}{CN}* =15+/- 1 {MeV}, so that the comparative analysis of reaction dynamics can be worked out. First of all, the fission barriers (B f ) and neutron separation energies ({S}1n) are estimated to account the decreasing cross-sections of cold fusion reactions. In addition to this, the importance of hot optimum orientations of β 2i-deformed nuclei over cold one is explored at fixed angular momentum and neck-length parameters. The hot optimum orientations support all the target-projectile (t,p) combinations, which are explored experimentally in the cold fusion reactions. Some new target-projectile combinations are also predicted for future exploration. Further, the 1n cross-sections are addressed for {Z}{CN}=104-113 superheavy nuclei at comparable excitation energies which show the decent agrement with experimental data upto {Z}{CN}=109 nuclei. Finally, to understand the dynamics of higher-Z superheavy nuclei, the cross-sections are also calculated at maximum available energies around the Coulomb barrier and the effect of non-sticking moment of inertia ({I}{NS}) is also investigated at these energies. Supported by the Council of Scientific and Industrial Research (CSIR), in the Form of Research Project Grant No. 03(1341)/15/EMR-II, and to DST, New Delhi, for INSPIRE-Fellowship Grant No. DST/INSPIRE/03/2015/000199

Experimental studies of tritium barrier concepts for fusion reactors

International Nuclear Information System (INIS)

Maroni, V.A.; Van Deventer, E.H.; Renner, T.A.; Pelto, R.H.; Wierdak, C.J.

1976-01-01

Ongoing experimental studies at ANL aimed at the development of methods to reduce tritium migration in fusion reactor systems currently include (1) work on the development of multilayered metal composites and impurity-coated refractory metals as barriers to tritium permeation in elevated temperature (greater than 300 0 C) structures and (2) investigations of the kinetics of tritium trapping reactions in inert gas purge streams under conditions that emulate fusion reactor environments. Significant results obtained thus far are (1) demonstration of greater than 50-fold reductions in the hydrogen permeability of stainless steel structures by using stainless steel-clad composites containing an intermediate layer of a selected copper alloy and (2) verification that surface-oxide coatings lead to greater than 100-fold reductions in the hydrogen permeability of vanadium, but that severe oxygen penetration and embrittlement of the vanadium occur at temperatures in the range from 300 to 800 0 C and under conditions of extremely low oxygen potential. Other considerations pertaining to the large-scale use of metal composites in fusion reactors are discussed, and progress in efforts to demonstrate the fabricability of metal composites is reviewed. Also presented are results of studies of the efficiencies of (1) CuO and CuO--MnO 2 beds in converting HT to HTO and (2) magnesium metal beds in converting HTO to HT

Design study of blanket structure for tokamak experimental fusion reactor

International Nuclear Information System (INIS)

1979-11-01

Design study of the blanket structure for JAERI Experimental Fusion Reactor (JXFR) has been carried out. Studied here were fabrication and testing of the blanket structure (blanket cells, blanket rings, piping and blanket modules), assembly and disassembly of the blanket module, and monitering and testing technique. Problems in design and fabrication of the blanket structure could be revealed. Research and development problems for the future were also disclosed. (author)

Fusion de-excitation process in heavy ion interactions

International Nuclear Information System (INIS)

Fleury, A.

1979-01-01

Various aspects of compound nucleus formation and de-excitation are analysed with particular emphasis on de-excitation by particle emission and fission. Calculations of level densities are described and the validity of various approximations studied. The explanatory and predictive possibilities of the statistical model are pointed out [fr

Open problems in sub-barrier fusion

International Nuclear Information System (INIS)

Vandenbosch, R.

1992-01-01

Two aspects of sub-barrier fusion are discussed. A challenge to the use of fission fragment angular distributions to probe the spin distribution in fusion is addressed. Evidence from excitation functions for the importance of neutron transfer and the neck degree of freedom is examined

Recent theoretical and experimental evidence on the cold fusion of elementary particles

International Nuclear Information System (INIS)

Santilli, R.M.

1993-01-01

Recent experiments have shown the apparent existence of the cold fusion/chemical synthesis of protons and electrons into neutrons (plus neutrinos), much along Rutherford's original conception. These findings have received indirect, yet significant experimental confirmations in Bose-Einstein correlations, superconductivity and other fields to warrant additional studies. In this paper we present a quantitative theoretical study of the apparent tendency of all massive particles to form a bound state at small distances which is enhanced at low energy. The study is centrally dependent on the isominkowskian geometrization of the expected nonlocal interactions due to total mutual penetrations, and their causal description via the isopoincare symmetry. The cold fusion considered is then made possible by isorenormalizations of the 'intrinsic' characteristics of particles originating from the contact-nonhamiltonian character of the internal nonlocal effects. This latter feature illustrates the reasons why the cold fusion considered is simply beyond the descriptive capacities of relativistic quantum mechanics, but it is fully predicted by its isotopic covering. 23 refs

Li2O-pebble type tritium breeding blanket for fusion experimental reactor, 1

International Nuclear Information System (INIS)

Tone, Tatsuzo; Iida, Hiromasa; Tanaka, Yoshihisa

1984-01-01

The fusion experimental reactor is the next stage device in Japan, which is planned to be constructed following the critical plasma experimental device JT-60 being constructed at present. The breeding blanket installed in nuclear fusion reactors is one of most important structures, and it is required to satisfy the fundamental performance of producing and continuously recovering tritium as the nuclear fusion fuel, and other requirement in good coordination. The Li 2 O pebble type breeding blanket that Kawasaki Heavy Industries Ltd. has examined is the concept for resolving the problems of the mass transfer and thermal stress cracking of Li 2 O, which are important in blanket design. In this paper, the concept and characteristics of this breeding blanket are discussed from the viewpoint of the breeding and continuous recovery of tritium, the ease of manufacture and the maintenance of soundness. The breeding blanket is composed of breeding region, tritium purge region, cooling region, plasma stabilizing conductors and blanket container. Li 2 O is excellent in its tritium breeding performance and heat conductivity. The functions required for the breeding blanket, the fundamental structure, the examples of breeding blanket concept, the selection of breeding blanket concept, the characteristics of Li 2 O pebble type blanket and its future prospect are described. (Kako, I.)

Design, calculation and experimental studies for liquid metal system main parameters in support of the liquid lithium fusion reactor

International Nuclear Information System (INIS)

Evtikhin, V.A.; Lyublinski, I.E.; Vertkov, A.V.

1999-01-01

A new concept of a Liquid Lithium Fusion Reactor and the first experimental results were presented at the 16th IAEA Conference on Fusion Energy. During the past two years theoretical estimations have been made, and calculated and experimental results have been obtained in confirmation of this concept and supporting its progress. The main results of this work are given in the paper. (author)

Design, calculation and experimental studies for liquid metal system main parameters in support of the liquid lithium fusion reactor

International Nuclear Information System (INIS)

Evtikhin, V.A.; Lyublinski, I.E.; Vertkov, A.V.

2001-01-01

A new concept of a Liquid Lithium Fusion Reactor and the first experimental results were presented at the 16th IAEA Conference on Fusion Energy. During the past two years theoretical estimations have been made, and calculated and experimental results have been obtained in confirmation of this concept and supporting its progress. The main results of this work are given in the paper. (author)

Fusion rates for hydrogen isotopic molecules of relevance for ''cold fusion''

International Nuclear Information System (INIS)

Szalewicz, K.; Morgan, J.D. III; Monkhorst, H.J.

1989-01-01

In response to the recent announcements of evidence for room-temperature fusion in the electrolysis of D 2 O, we have analyzed how the fusion rate depends on the reduced mass of the fusing nuclei, the effective mass of a ''heavy'' electron, and the degree of vibrational excitation. Our results have been obtained both by accurately solving the Schroedinger equation for the hydrogen molecule and by using the WKB approximation. We find that in light of the reported d-d fusion rate, the excess heat in the experiment by Fleischmann, Pons, and Hawkins [J. Electroanal. Chem. 261, 301 (1989)] is difficult to explain in terms of conventional nuclear processes

Conceptual design of fusion experimental reactor (FER)

International Nuclear Information System (INIS)

1984-01-01

Conceptual Design of Fusion Experimental Reactor (FER) of which the objective will be to realize self-ignition with D-T reaction is reported. Mechanical Configurations of FER are characterized with a noncircular plasma and a double-null divertor. The primary aim of design studies is to demonstrate fissibility of reactor structures as compact and simple as possible with removable torus sectors. The structures of each component such as a first-wall, blanket, shielding, divertor, magnet and so on have been designed. It is also discussed about essential reactor plant system requirements. In addition to the above, a brief concept of a steady-state reactor based on RF current drive is also discussed. The main aim, in this time, is to examine physical studies of a possible RF steady-state reactor. (author)

35Cl + 12C asymmetrical fission excitation functions

International Nuclear Information System (INIS)

Beck, C.; Mahboub, D.; Nouicer, R.; Freeman, R.M.; Haas, F.; Youlal, M.; Matsuse, T.; Sanders, S.J.

1996-04-01

The fully energy-damped yields from the 35 Cl + 12 C reaction have been systematically investigated using particle-particle coincidence techniques at a 35 Cl bombarding energy of ∼ 8 MeV/nucleon. The fragment-fragment correlation data show that the majority of events arises from a binary-decay process with rather large numbers of secondary light-charged particles emitted from the two excited exit fragments. No evidence is observed for ternary breakup events. The binary-process results of the present measurement, along with those of earlier, inclusive experimental data obtained at several lower bombarding energies are compared with predictions of two different kinds of statistical model calculations. The methods give comparable predictions and are both in good agreement with the experimental results thus confirming the fusion-fission origin of the fully-damped yields. (author)

An experimental and theoretical investigation into the excited electronic states of phenol

Energy Technology Data Exchange (ETDEWEB)

Jones, D. B.; Chiari, L. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Silva, G. B. da [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso (Brazil); Neves, R. F. C. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Departamento de Física, UFJF, Juiz de Fora, MG (Brazil); Instituto Federal do Sul de Minas Gerais, Campus Poços de Caldas, Minas Gerais (Brazil); Duque, H. V. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Departamento de Física, UFJF, Juiz de Fora, MG (Brazil); Oliveira, E. M. de; Lima, M. A. P. [Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo (Brazil); Lopes, M. C. A. [Departamento de Física, UFJF, Juiz de Fora, MG (Brazil); Costa, R. F. da [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-580 Santo André, São Paulo (Brazil); Varella, M. T. do N. [Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970 São Paulo (Brazil); Bettega, M. H. F. [Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná (Brazil); and others

2014-08-21

We present experimental electron-energy loss spectra (EELS) that were measured at impact energies of 20 and 30 eV and at angles of 90° and 10°, respectively, with energy resolution ∼70 meV. EELS for 250 eV incident electron energy over a range of angles between 3° and 50° have also been measured at a moderate energy resolution (∼0.9 eV). The latter spectra were used to derive differential cross sections and generalised oscillator strengths (GOS) for the dipole-allowed electronic transitions, through normalization to data for elastic electron scattering from benzene. Theoretical calculations were performed using time-dependent density functional theory and single-excitation configuration interaction methods. These calculations were used to assign the experimentally measured spectra. Calculated optical oscillator strengths were also compared to those derived from the GOS data. This provides the first investigation of all singlet and triplet excited electronic states of phenol up to the first ionization potential.

Electron Impact Excitation and Dielectronic Recombination of Highly Charged Tungsten Ions

Directory of Open Access Journals (Sweden)

Zhongwen Wu

2015-11-01

Full Text Available Electron impact excitation (EIE and dielectronic recombination (DR of tungsten ions are basic atomic processes in nuclear fusion plasmas of the International Thermonuclear Experimental Reactor (ITER tokamak. Detailed investigation of such processes is essential for modeling and diagnosing future fusion experiments performed on the ITER. In the present work, we studied total and partial electron-impact excitation (EIE and DR cross-sections of highly charged tungsten ions by using the multiconfiguration Dirac–Fock method. The degrees of linear polarization of the subsequent X-ray emissions from unequally-populated magnetic sub-levels of these ions were estimated. It is found that the degrees of linear polarization of the same transition lines, but populated respectively by the EIE and DR processes, are very different, which makes diagnosis of the formation mechanism of X-ray emissions possible. In addition, with the help of the flexible atomic code on the basis of the relativistic configuration interaction method, DR rate coefficients of highly charged W37+ to W46+ ions are also studied, because of the importance in the ionization equilibrium of tungsten plasmas under running conditions of the ITER.

Conceptual design study of quasi-steady state fusion experimental reactor (FEQ-Q), part 1

International Nuclear Information System (INIS)

1985-12-01

Since 1980 the design study has been conducted at JAERI for the Fusion Experimental Reactor (FER) which has been proposed to be the next machine to JT-60 in the Japanese long term program of fusion reactor development. Starting from 1984 JER design is being reviewed and redesigned. This report is a part of the interim report which describes the results obtained in the review and redesign activities in FY 1984. The results of the following design items are included; core plasma, reactor structure, reactor core components, magnets. (author)

Estimating Total Fusion Cross Sections by Using a Coupled-Channel Method

Energy Technology Data Exchange (ETDEWEB)

Choi, Ki-Seok; Cheoun, Myung-Ki [Soongsil University, Seoul (Korea, Republic of); Kim, K. S. [Korea Aerospace University, Koyang (Korea, Republic of); Kim, T. H.; So, W. Y. [Kangwon National University at Dogye, Samcheok (Korea, Republic of)

2017-01-15

We calculate the total fusion cross sections for the {sup 6}He + {sup 209}Bi, {sup 6}Li + {sup 209}Bi,{sup 9}Be + {sup 208}Pb, {sup 10}Be + {sup 209}Bi, and {sup 11}Li + {sup 208}Pb systems by using a coupled-channel (CC) method and compare the results with the experimental data. In the CC approach for the total fusion cross sections, we exploit a globally determined Wood-Saxon potential with Aky¨uz-Winther parameters and couplings of the ground state to the low-lying excited states in the projectile and the target nuclei. The total fusion cross sections obtained with the CC are compared with those obtained without the CC couplings. The latter approach is tantamount to a one-dimensional barrier penetration model. Finally, our approach is applied to understand new data for the {sup 11}Li+{sup 208}Pb system. Possible ambiguities inherent in those approaches are discussed in detail for further applications to the fusion system of halo and/or neutron-rich nuclei.

Present activities for the preparation of a Japanese draft of structural design guidelines for the experimental fusion reactor

International Nuclear Information System (INIS)

Miya, K.; Muto, Y.; Takatsu, H.; Hada, K.; Koizumi, K.; Jitsukawa, S.; Arai, T.; Ohkawa, Y.; Shimakawa, T.; Aoto, K.; Shiraishi, H.; Takagi, T.; Miki, N.; Takahashi, S.; Sato, K.; Takemasa, F.; Kasaba, M.; Kudough, F.; Fujita, J.; Kajiura, S.; Kinoshita, S.

1996-01-01

Since November 1990, systematic research has been carried out in preparation for a Japanese draft of structural design guidelines for the experimental fusion reactor. This report summarizes the major results of the work and the status of these efforts. A classification of components and definition of operating conditions are proposed on the basis of the ITER-CDA design, in the light of the safety characteristics of the fusion reactor and relevant conventions for the existing fission reactor design code. Specific issues regarding the structural design of the experimental fusion reactor are discussed based on the experimental and analytical work. The validity of the existing structural design method is confirmed for the use of irradiated 316 SS, irrespective of the significant reduction in uniform elongation capability caused by heavy neutron irradiation. Further important phenomena are treated such as magnetic damping, magnetic stiffness and fracture due to electromagnetic forces. Finally, the issues concerned with welding and non-destructive examinations are discussed with relevance to component classification. (orig.)

Second preliminary design of JAERI experimental fusion reactor (JXFR)

International Nuclear Information System (INIS)

Sako, Kiyoshi; Tone, Tatsuzo; Seki, Yasushi; Iida, Hiromasa; Yamato, Harumi

1979-06-01

Second preliminary design of a tokamak experimental fusion reactor to be built in the near future has been performed. This design covers overall reactor system including plasma characteristics, reactor structure, blanket neutronics radiation shielding, superconducting magnets, neutral beam injector, electric power supply system, fuel recirculating system, reactor cooling and tritium recovery systems and maintenance scheme. Safety analyses of the reactor system have been also performed. This paper gives a brief description of the design as of January, 1979. The feasibility study of raising the power density has been also studied and is shown as appendix. (author)

Experimental studies on cold fusion and hydrogen-metal

International Nuclear Information System (INIS)

Locou, P.

2007-01-01

The cold fusion is a nuclear fusion realized in pervading conditions of temperature and pressure. My own process is parallel to that of the team of the University of Los Angeles, but shaped in 1996 within my personal and private Laboratory: A small cylinder in which we replace the air by some deuterium to the gas state in - 33 d egree (the deuterium is some hydrogen with a neutron, which we find in quantity in the sea water). We introduce a crystal there, extremely rare - the property of which is to emit continuously one thousand times dose of successful energy and it during several years without outside pyro, natural excitement - electric - that is it creates an electric field in the slightest change in temperature. We carry then the whole in + 7 d egree, what generates in some seconds a 200 000 volt electric field, an intense enough field to separate the pits of the deuterium of their electrons and to admit them to collide with those of the crystal. There is a fusion of protons between them (positive particles of the pit (core)) and a emission of neutrons, which do not merge. It is this emission which serves for measuring the quantity of energy produced by the fusion (merger). We so managed to produce some energy in unlimited quantity, allowing us to feed our installation with electric current in total autarky, and to reduce so our costs of functioning to divers domains. This crystal is exceptional in its applications and to give it the name would return has to break our current headway: the thorough problem, in this current period of takeover by the financial bodies of the possible patents, brought to us to the biggest caution as regards our results. And, as we look for no outside financing, we do not need to submit ourselves to the requirements lauded by the scientific Community, only our results are strictly estimated. For example we can make estimate our bars or patches of Hydrogen - Metal: a simple spectroscopy in YEW will give as result, only, the element H

Elastic scattering, fusion, and breakup of light exotic nuclei

Energy Technology Data Exchange (ETDEWEB)

Kolata, J.J. [University of Notre Dame, Physics Department, Notre Dame, IN (United States); Guimaraes, V. [Universidade de Sao Paulo, Instituto de Fisica, Sao Paulo, SP (Brazil); Aguilera, E.F. [Instituto Nacional de Investigaciones Nucleares, Departamento de Aceleradores, Mexico, Distrito Federal (Mexico)

2016-05-15

The present status of fusion reactions involving light (A< 20) radioactive projectiles at energies around the Coulomb barrier (E<10 MeV per nucleon) is reviewed, emphasizing measurements made within the last decade. Data on elastic scattering (providing total reaction cross section information) and breakup channels for the involved systems, demonstrating the relationship between these and the fusion channel, are also reviewed. Similarities and differences in the behavior of fusion and total reaction cross section data concerning halo nuclei, weakly-bound but less exotic projectiles, and strongly-bound systems are discussed. One difference in the behavior of fusion excitation functions near the Coulomb barrier seems to emerge between neutron-halo and proton-halo systems. The role of charge has been investigated by comparing the fusion excitation functions, properly scaled, for different neutron- and proton-rich systems. Possible physical explanations for the observed differences are also reviewed. (orig.)

Excited states v.6

CERN Document Server

Lim, Edward C

1982-01-01

Excited States, Volume 6 is a collection of papers that discusses the excited states of molecules. The first paper discusses the linear polyene electronic structure and potential surfaces, considering both the theoretical and experimental approaches in such electronic states. This paper also reviews the theory of electronic structure and cites some experimental techniques on polyene excitations, polyene spectroscopic phenomenology, and those involving higher states of polyenes and their triplet states. Examples of these experimental studies of excited states involve the high-resolution one-pho

Maximum neutron yeidls in experimental fusion devices

International Nuclear Information System (INIS)

Jassby, D.L.

1979-02-01

The optimal performances of 12 types of fusion devices are compared with regard to neutron production rate, neutrons per pulse, and fusion energy multiplication, Q/sub p/ (converted to the equivalent value in D-T operation). The record values in all categories are held by the beam-injected tokamak plasma, followed by other beam-target systems. The achieved values of Q/sub p/ for nearly all laboratory plasma fusion devices (magnetically or inertially confined) are found to roughly satisfy a common empirical scaling, Q/sub p/ approx. 10 -6 E/sub in//sup 3/2/, where E/sub in/ is the energy (in kilojoules) injected into the plasma during one or two energy confinement times, or the total energy delivered to the target for inertially confined systems. Fusion energy break-even (Q/sub p/ = 1) in any system apparently requires E/sub in/ approx. 10,000 kJ

External events analysis for experimental fusion facilities

International Nuclear Information System (INIS)

Cadwallader, L.C.

1990-01-01

External events are those off-normal events that threaten facilities either from outside or inside the building. These events, such as floods, fires, and earthquakes, are among the leading risk contributors for fission power plants, and the nature of fusion facilities indicates that they may also lead fusion risk. This paper gives overviews of analysis methods, references good analysis guidance documents, and gives design tips for mitigating the effects of floods and fires, seismic events, and aircraft impacts. Implications for future fusion facility siting are also discussed. Sites similar to fission plant sites are recommended. 46 refs

Fusion of 48Ti+58Fe and 58Ni+54Fe below the Coulomb barrier

Science.gov (United States)

Stefanini, A. M.; Montagnoli, G.; Corradi, L.; Courtin, S.; Bourgin, D.; Fioretto, E.; Goasduff, A.; Grebosz, J.; Haas, F.; Mazzocco, M.; Mijatović, T.; Montanari, D.; Pagliaroli, M.; Parascandolo, C.; Scarlassara, F.; Strano, E.; Szilner, S.; Toniolo, N.; Torresi, D.

2015-12-01

Background: No data on the fusion excitation function of 48Ti+58Fe in the energy region near the Coulomb barrier existed prior to the present work, while fusion of 58Ni+54Fe was investigated in detail some years ago, down to very low energies, and clear evidence of fusion hindrance was noticed at relatively high cross sections. 48Ti and 58Fe are soft and have a low-lying quadrupole excitation lying at ≈800 -900 keV only. Instead, 58Ni and 54Fe have a closed shell (protons and neutrons, respectively) and are rather rigid. Purpose: We aim to investigate (1) the possible influence of the different structures of the involved nuclei on the fusion excitation functions far below the barrier and, in particular, (2) whether hindrance is observed in 48Ti+58Fe , and to compare the results with current coupled-channels models. Methods: 48Ti beams from the XTU Tandem accelerator of INFN-Laboratori Nazionali di Legnaro were used. The experimental setup was based on an electrostatic beam separator, and fusion-evaporation residues (ERs) were detected at very forward angles. Angular distributions of ERs were measured. Results: Fusion cross sections of 48Ti+58Fe have been obtained in a range of nearly six orders of magnitude around the Coulomb barrier, down to σ ≃2 μ b . The sub-barrier cross sections of 48Ti+58Fe are much larger than those of 58Ni+54Fe . Significant differences are also observed in the logarithmic derivatives and astrophysical S factors. No evidence of hindrance is observed, because coupled-channels calculations using a standard Woods-Saxon potential are able to reproduce the data in the whole measured energy range. Analogous calculations for 58Ni+54Fe predict clearly too large cross sections at low energies. The two fusion barrier distributions are wide and display a complex structure that is only qualitatively fit by calculations. Conclusions: It is pointed out that all these different trends originate from the dissimilar low-energy nuclear structures of

Energy balance of controlled thermonuclear fusion

International Nuclear Information System (INIS)

Hashmi, M.; Staudenmaier, G.

2000-01-01

It is shown that a discrepancy and incompatibility persist between basic physics and fusion-literature regarding the radiation losses from a thermonuclear plasma. Whereas the fusion-literature neglects the excitation or line radiation completely, according to basic physics it depends upon the prevailing conditions and cannot be neglected in general. Moreover, for a magnetized plasma, while the fusion-literature assumes a self-absorption or reabsorption of cyclotron or synchrotron radiation emitted by the electrons spiraling along the magnetic field, the basic physics does not allow any effective reabsorption of cyclotron or synchrotron radiation. As is demonstrated, fallacious assumptions and notions, which somehow or other crept into the fusion-literature, are responsible for this discrepancy. In the present work, the theory is corrected. On the grounds of basic physics, a complete energy balance of magnetized and non-magnetized plasmas is presented for pulsed, stationary and self-sustaining operations by taking into account the energy release by reactions of light nuclei as well as different kinds of diffusive (conduction) and radiative (bremsstrahlung, cyclotron or synchrotron radiation and excitation radiation) energy losses. Already the energy losses by radiation make the energy balance negative. Hence, a fusion reactor-an energy producing device-seems to be beyond the realms of realization. (orig.)

Current experimental situation in heavy-ion reactions

International Nuclear Information System (INIS)

Scott, D.K.

1978-06-01

A detailed survey of the present experimental situation in heavy-ion physics is presented. The discussion begins by considering the simple excitation of discrete states in elastic scattering, transfer, and compound-nucleus reactions; it then turns to more drastic perturbations of the nucleus high in the continuum through fusion, fission, and deeply inelastic scattering, and concludes with the (possibly) limiting asymptotic phenomena of relativistic heavy-ion collisions. 138 figures, 5 tables, 451 references

Conceptual design study of quasi-steady state fusion experimental reactor (FER-Q), part 2

International Nuclear Information System (INIS)

1985-12-01

Since 1980 the design study has been conducted at JAERI for the Fusion Experimental Reactor (FER) which has been proposed to be the next machine to JT-60 in the Japanese long term program of fusion reactor development. Starting from 1984 FER design is being reviewed and redesigned. This report is a part of the interim report which describes the results obtained in the review and redesign activities in FY 1984. The results of the following design items are included: heating/current drive system, plasma position control, power supply, diagnostics, neutronics, blanket test module, repair and maintenance and safety. (author)

Higher order modes excitation of electrostatically actuated clamped–clamped microbeams: experimental and analytical investigation

KAUST Repository

Jaber, Nizar; Ramini, Abdallah; Carreno, Armando Arpys Arevalo; Younis, Mohammad I.

2016-01-01

© 2016 IOP Publishing Ltd. In this study, we demonstrate analytically and experimentally the excitations of the higher order modes of vibrations in electrostatically actuated clamped-clamped microbeam resonators. The concept is based on using

Experimental system to measure excitation cross-sections by electron impact. Measurements for ArI and ArII

International Nuclear Information System (INIS)

Blanco, F.; Sanchez, J.A.; Aguilera, J.A.; Campos, J.

1989-01-01

An experimental set-up to measure excitation cross-section of atomic and molecular levels by electron impact based on the optical method is reported. We also present some measurements on the excitation cross-section for ArI 5p'(1/2)0 level, and for simultaneous ionization and excitation of Ar leading to ArII levels belonging to the 3p 4 4p and 3p 4 4d configurations. (Author)

Conceptual design of fusion experimental reactor (FER)

International Nuclear Information System (INIS)

1985-01-01

The Fusion Experimental Reactor (FER) being developed at JAERI as a next generation tokamak to JT-60 has a major mission of realizing a self-ignited long-burning DT plasma and demonstrating engineering feasibility. During FY82 and FY83 a comprehensive and intensive conceptual design study has been conducted for a pulsed operation FER as a reference option which employs a conventional inductive current drive and a double-null divertor. In parallel with the reference design, studies have been carried out to evaluate advanced reactor concepts such as quasi-steady state operation and steady state operation based on RF current drive and pumped limiter, and comparative studies for single-null divertor/pumped limiter. This report presents major results obtained primarily from FY83 design studies, while the results of FY82 design studies are described in previous references (JAERI-M 83-213--216). (author)

Conceptual design study of fusion experimental reactor (FY86 FER)

International Nuclear Information System (INIS)

Kobayashi, Takeshi; Yamada, Masao; Mizoguchi, Tadanori

1987-09-01

This report describes the results of the reactor configuration/structure design for the fusion experimental reactor (FER) performed in FY 1986. The design was intended to meet the physical and engineering mission of the next step device which was decided by the subcommittee on the next step device of the nuclear fusion council. The objectives of the design study in FY 1986 are to advance and optimize the design concept of the last year because the recommendation of the subcommittee was basically the same as the design philosophy of the last year. Six candidate reactor configurations which correspond to options C ∼ D presented by the subcommittee were extensively examined. Consequently, ACS reactor (Advanced Option-C with Single Null Divertor) was selected as the reference configuration from viewpoints of technical risks and cost performance. Regarding the reactor structure, the following items were investigated intensively: minimization of reactor size, protection of first wall against plasma disruption, simplification of shield structure, reactor configuration which enables optimum arrangement of poloidal field coils. (author)

Barrier distribution in the heavy-ions fusion near Coulomb barrier

International Nuclear Information System (INIS)

Shilov, V.M.

1992-01-01

Experimental data on fusion cross section and average angular momenta of the compound nucleus are analyzed on the basis of the coupled-channel model for the reactions 32 S+ 100 Mo and 36 S+ 96 Mo. It is shown that it is important to take into account the transfer channels with positive value Q r for the description of the data. The intermediate coupling between excited states changes the distribution of barriers and approximates them to the ones of the Stelson phenomenological model. 22 refs.; 4 figs.; 2 tabs

Isomer depletion as experimental evidence of nuclear excitation by electron capture

Science.gov (United States)

Chiara, C. J.; Carroll, J. J.; Carpenter, M. P.; Greene, J. P.; Hartley, D. J.; Janssens, R. V. F.; Lane, G. J.; Marsh, J. C.; Matters, D. A.; Polasik, M.; Rzadkiewicz, J.; Seweryniak, D.; Zhu, S.; Bottoni, S.; Hayes, A. B.; Karamian, S. A.

2018-02-01

The atomic nucleus and its electrons are often thought of as independent systems that are held together in the atom by their mutual attraction. Their interaction, however, leads to other important effects, such as providing an additional decay mode for excited nuclear states, whereby the nucleus releases energy by ejecting an atomic electron instead of by emitting a γ-ray. This ‘internal conversion’ has been known for about a hundred years and can be used to study nuclei and their interaction with their electrons. In the inverse process—nuclear excitation by electron capture (NEEC)—a free electron is captured into an atomic vacancy and can excite the nucleus to a higher-energy state, provided that the kinetic energy of the free electron plus the magnitude of its binding energy once captured matches the nuclear energy difference between the two states. NEEC was predicted in 1976 and has not hitherto been observed. Here we report evidence of NEEC in molybdenum-93 and determine the probability and cross-section for the process in a beam-based experimental scenario. Our results provide a standard for the assessment of theoretical models relevant to NEEC, which predict cross-sections that span many orders of magnitude. The greatest practical effect of the NEEC process may be on the survival of nuclei in stellar environments, in which it could excite isomers (that is, long-lived nuclear states) to shorter-lived states. Such excitations may reduce the abundance of the isotope after its production. This is an example of ‘isomer depletion’, which has been investigated previously through other reactions, but is used here to obtain evidence for NEEC.

Fusion energy division computer systems network

International Nuclear Information System (INIS)

Hammons, C.E.

1980-12-01

The Fusion Energy Division of the Oak Ridge National Laboratory (ORNL) operated by Union Carbide Corporation Nuclear Division (UCC-ND) is primarily involved in the investigation of problems related to the use of controlled thermonuclear fusion as an energy source. The Fusion Energy Division supports investigations of experimental fusion devices and related fusion theory. This memo provides a brief overview of the computing environment in the Fusion Energy Division and the computing support provided to the experimental effort and theory research

Experimental measurement of 12C+16O fusion at stellar energies

Science.gov (United States)

Fang, X.; Tan, W. P.; Beard, M.; deBoer, R. J.; Gilardy, G.; Jung, H.; Liu, Q.; Lyons, S.; Robertson, D.; Setoodehnia, K.; Seymour, C.; Stech, E.; Vande Kolk, B.; Wiescher, M.; deSouza, R. T.; Hudan, S.; Singh, V.; Tang, X. D.; Uberseder, E.

2017-10-01

The total cross section of the 12C+16O fusion reaction has been measured at low energies to investigate the role of this reaction during late stellar evolution burning phases. A high-intensity oxygen beam, produced by the 5 MV pelletron accelerator at the University of Notre Dame, impinged on a thick, ultrapure graphite target. Protons and γ rays were simultaneously measured in the center-of-mass energy range from 3.64 to 5.01 MeV for singles and from 3.73 to 4.84 MeV for coincidence events, using silicon and Ge detectors. Statistical model calculations were employed to interpret the experimental results. The emergence of a new resonance-like broad structure and a decreasing trend in the S -factor data towards lower energies (opposite to previous data) are found for the 12C+16O fusion reaction. Based on these results the uncertainty range of the reaction rate within the temperature range of late stellar burning environments is discussed.

Simulation of the control rod drop under seismic excitations. Experimental program

International Nuclear Information System (INIS)

Chaudat, Th.

2001-01-01

This paper describes the experimental program that will be performed at the end of 1998 at the CEA Saclay on a specially constructed analytical mock-up of a control rod. The purpose of these tests is to partially validate the current methodology of the drop time numerical calculations of a PWR (pressurized water reactor) control rod under seismic excitations. The French nuclear partners (EDF and FRAMATOME) are involved in this program. (author)

The ITER fusion reactor and its role in the development of a fusion power plant

International Nuclear Information System (INIS)

McLean, A.

2002-01-01

Energy from nuclear fusion is the future source of sustained, full life-cycle environmentally benign, intrinsically safe, base-load power production. The nuclear fusion process powers our sun, innumerable other stars in the sky, and some day, it will power the Earth, its cities and our homes. The International Thermonuclear Experimental Reactor, ITER, represents the next step toward fulfilling that promise. ITER will be a test bed for key steppingstones toward engineering feasibility of a demonstration fusion power plant (DEMO) in a single experimental step. It will establish the physics basis for steady state Tokamak magnetic containment fusion reactors to follow it, exploring ion temperature, plasma density and containment time regimes beyond the breakeven power condition, and culminating in experimental fusion self-ignition. (author)

The FENIX [Fusion ENgineering International EXperimental] test facility

International Nuclear Information System (INIS)

Slack, D.S.; Patrick, R.E.; Chaplin, M.R.; Miller, J.R.; Shen, S.S.; Summers, L.T.; Kerns, J.A.

1989-01-01

The Fusion ENgineering International EXperimental Magnet Facility (FENIX), under construction at Lawrence Livermore National Laboratory (LLNL), is a significant step forward in meeting the testing requirements necessary for the development of superconductor for large-scale, superconducting magnets. A 14-T, transverse field over a test volume of 150 x 60 x 150 mm in length will be capable of testing conductors the size of the International Thermonuclear Experimental Reactor (ITER). Proposed conductors for ITER measure ∼35 mm on one side and will operate at currents of up to 40 kA at fields of ∼14 T. The testing of conductors and associated components, such as joints, will require large-bore, high-field magnet facilities. FENIX is being constructed using the existing A 2o and A 2i magnets from the idle MFTF. The east and west A 2 pairs will be mounted together to form a split-pair solenoid. The pairs of magnets will be installed in a 4.0-m cryostat vessel located in the HFTF building at LLNL. Each magnet is enclosed in its own cryostat, the existing 4.0-m vessel serving only as a vacuum chamber. 4 refs., 8 figs

Feasibility study of teleoperational maintenance using real-time simulator for experimental fusion reactor

International Nuclear Information System (INIS)

Hamada, Tomoyuki; Tanaka, Keiji; Oka, Kiyoshi; Shibanuma, Kiyoshi

2004-01-01

The maintenance manipulator for the experimental fusion reactor has long vertical and horizontal telescopic booms to access the neutral beam injector of the fusion reactor. Due to this boom structure, the vibration and deflection of the manipulator are the critical issues for the accurate operation. A real-time simulation system was constructed to evaluate the maneuverability of the manipulator under these vibration and deflection. In this simulation system, the dynamic behavior of the flexible manipulator is calculated synchronized with the real-time control input of the human operator. A vibration and position compensation method was adapted to improve the maneuverability. Through the evaluation using the real-time simulation system, it was verified that the manipulator is maneuverable by using vibration and position compensation. (author)

Fusion of 16O+46,50Ti near and below the Coulomb barrier

International Nuclear Information System (INIS)

Liguori Neto, R.; Acquadro, J.C.; Gomes, P.R.S.; Toledo, A.S. de; Crema, E.; Carlin Filho, N.; Coimbra, M.M.

1988-11-01

Fusion excitation functions for the systems 16 O+ 46 , 50 Ti at bombarding energies in the range 30 MeV ≤ E LAB ( 16 O) ≤ 65 MeV were measured by means of the γ-ray spectroscopy technique. The fusion excitation functions are analysed using a semi-classical one-dimensional barrier-penetration model with different nuclear potentials describing the heavy-ion interaction. From the analysis the fusion barrier parameters were obtained. The observed fusion cross sections at subbarrier energies are larger than predicted by this conventional one-dimensional barrier-penetration model. The fusion enhacement at sub-barrier energies for these systems can be explained by the simple approach of Wong's model, considering explicitly the quadrupole deformation parameter of the target-nucleus. (author) [pt

The Penning fusion experiment-ions

International Nuclear Information System (INIS)

Schauer, M. M.; Umstadter, K. R.; Barnes, D. C.

1999-01-01

The Penning fusion experiment (PFX) studies the feasibility of using a Penning trap as a fusion confinement device. Such use would require spatial and/or temporal compression of the plasma to overcome the Brillouin density limit imposed by the nonneutrality of Penning trap plasmas. In an earlier experiment, we achieved enhanced plasma density at the center of a pure, electron plasma confined in a hyperbolic, Penning trap by inducing spherically convergent flow in a nonthermal plasma. The goal of this work is to induce similar flow in a positive ion plasma confined in the virtual cathode provided by a spherical, uniform density electron plasma. This approach promises the greatest flexibility in operating with multi-species plasmas (e.g. D + /T + ) or implementing temporal compression schemes such as the Periodically Oscillating Plasma Sphere of Nebel and Barnes. Here, we report on our work to produce and diagnose the necessary electron plasma

Experimental determination of electron shock excitation cross sections for a singly charged gadolinium ion

International Nuclear Information System (INIS)

Smirnov, Yu.M.

1995-01-01

The trends observed in the processes of excitation with simultaneous ionization have received little study. This is particularly so for rare-earth elements having electron shells of complex structure and optical spectra very rich in lines. Among the basic factors responsible for such a situation, we should mention two: the difficulty presented by theoretical analysis of the processes discussed and the absence of factual information about the excitation cross sections with simultaneous ionization for the majority of rare-earth elements. The aim of the present work is to investigate the excitation of a singly charged gadolinium ion in the collisions of monokinetic electrons with gadolinium atoms. Up to the present time, only the excitation cross sections of a gadolinium atom have been measured, where investigation of the electron shock excitation of gadolinium atoms in their free state is associated with overcoming large experimental difficulties. About 160 crosss sections for the excitation of a singly charged gadolinium ion were measured and for a third of the cross sections; the energy dependences were recorded for the change in energy of the elecrons from the excitation threshold up to 200 eV. Included are tables of the wavelength, transistion, internal quantum number, the energy of the lowere and upper levels, and the values of cross sections for the charged gadolinium ion. Diagrams of the transistion energy states of Gd (II) and spectroscopy are presented and explained

Collective dynamics of nuclear fusion: deformation changes and heating during the fusion

International Nuclear Information System (INIS)

Mikhailov, I.N.; Mikhailova, T.I.; Toro, M. di; Baran, V.; Briancon, C.

1996-01-01

The formalism developed elsewhere for the theoretical description of the dynamics involved in the heavy nucleus fusion is applied in this paper to study the history of the fusion of two identical heavy nuclei experiencing central collision. The evolution of the shape and of the temperature of symmetrical fusing systems is studied. The role of the elastoplasticity of nuclear matter in the nonmonotonical changes of the shape is elucidated in this way. A tentative explanation of the ''extra push'' phenomenon is given in terms of the competition between elastic properties of fusing systems driving to the re-separation of colliding nuclei and the dissipative (plastic) properties of nuclear matter transforming the energy of collective motion into the energy of statistical excitation and thus leading to the fusion. The fingerprints of the heavy-nucleus fusion history as it is depicted by the model are traced in the anisotropy of the dipole and quadrupole γ-radiation emitted during the fusion. The parallels in the description of the fusion dynamics given by the simple model used in this paper and by the more fundamental approaches based on the kinetic equation are emphasised. (orig.)

Comparison of various structural damage tracking techniques with unknown excitations based on experimental data

Science.gov (United States)

Huang, Hongwei; Yang, Jann N.; Zhou, Li

2009-03-01

An early detection of structural damages is critical for the decision making of repair and replacement maintenance in order to guarantee a specified structural reliability. Consequently, the structural damage detection, based on vibration data measured from the structural health monitoring (SHM) system, has received considerable attention recently. The traditional time-domain analysis techniques, such as the least square estimation (LSE) method and the extended Kalman filter (EKF) approach, require that all the external excitations (inputs) be available, which may not be the case for some SHM systems. Recently, these two approaches have been extended to cover the general case where some of the external excitations (inputs) are not measured, referred to as the LSE with unknown inputs (LSE-UI) and the EKF with unknown inputs (EKF-UI). Also, new analysis methods, referred to as the sequential non-linear least-square estimation with unknown inputs and unknown outputs (SNLSE-UI-UO) and the quadratic sum-square error with unknown inputs (QSSE-UI), have been proposed for the damage tracking of structures when some of the acceleration responses are not measured and the external excitations are not available. In this paper, these newly proposed analysis methods will be compared in terms of accuracy, convergence and efficiency, for damage identification of structures based on experimental data obtained through a series of experimental tests using a small-scale 3-story building model with white noise excitation. The capability of the LSE-UI, EKF-UI, SNLSE-UI-UO and QSSE-UI approaches in tracking the structural damages will be demonstrated.

Inertial confinement fusion (ICF)

International Nuclear Information System (INIS)

Nuckolls, J.

1977-01-01

The principal goal of the inertial confinement fusion program is the development of a practical fusion power plant in this century. Rapid progress has been made in the four major areas of ICF--targets, drivers, fusion experiments, and reactors. High gain targets have been designed. Laser, electron beam, and heavy ion accelerator drivers appear to be feasible. Record-breaking thermonuclear conditions have been experimentally achieved. Detailed diagnostics of laser implosions have confirmed predictions of the LASNEX computer program. Experimental facilities are being planned and constructed capable of igniting high gain fusion microexplosions in the mid 1980's. A low cost long lifetime reactor design has been developed

Excitation energy dependence of fragment-mass distributions from fission of 180,190Hg formed in fusion reactions of 36Ar + 144,154Sm

Directory of Open Access Journals (Sweden)

K. Nishio

2015-09-01

Full Text Available Mass distributions of fission fragments from the compound nuclei 180Hg and 190Hg formed in fusion reactions 36Ar + 144Sm and 36Ar + 154Sm, respectively, were measured at initial excitation energies of E⁎(Hg180=33–66 MeV and E⁎(Hg190=48–71 MeV. In the fission of 180Hg, the mass spectra were well reproduced by assuming only an asymmetric-mass division, with most probable light and heavy fragment masses A¯L/A¯H=79/101. The mass asymmetry for 180Hg agrees well with that obtained in the low-energy β+/EC-delayed fission of 180Tl, from our earlier ISOLDE(CERN experiment. Fission of 190Hg is found to proceed in a similar way, delivering the mass asymmetry of A¯L/A¯H=83/107, throughout the measured excitation energy range. The persistence as a function of excitation energy of the mass-asymmetric fission for both proton-rich Hg isotopes gives strong evidence for the survival of microscopic effects up to effective excitation energies of compound nuclei as high as 40 MeV. This behavior is different from fission of actinide nuclei and heavier mercury isotope 198Hg.

Fusion Imaging for Procedural Guidance.

Science.gov (United States)

Wiley, Brandon M; Eleid, Mackram F; Thaden, Jeremy J

2018-05-01

The field of percutaneous structural heart interventions has grown tremendously in recent years. This growth has fueled the development of new imaging protocols and technologies in parallel to help facilitate these minimally-invasive procedures. Fusion imaging is an exciting new technology that combines the strength of 2 imaging modalities and has the potential to improve procedural planning and the safety of many commonly performed transcatheter procedures. In this review we discuss the basic concepts of fusion imaging along with the relative strengths and weaknesses of static vs dynamic fusion imaging modalities. This review will focus primarily on echocardiographic-fluoroscopic fusion imaging and its application in commonly performed transcatheter structural heart procedures. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Plasma fluctuations and confinement of fusion reaction products

International Nuclear Information System (INIS)

Coppi, B.; Pegoraro, F.

1981-01-01

The interaction between the fluctuations that can be excited in a magnetically confined plasma and the high-energy-particle population produced by fusion reactions is analyzed in view of its relevance to the process of thermonuclear ignition. The spectrum of the perturbations that, in the absence of fusion reaction products, would be described by the incompressible ideal magnetohydrodynamic approximation is studied considering finite value of the plasma pressure relative ot the magnetic pressure. The combined effects of the magnetic field curvature and shear are taken into account and the relevant spectrum is shown to consist of a continuous portion, that could be identified as a mixture of shear-Alfven and interchange oscillations, and a discrete unstable part corresponding to the so-called ballooning modes. The rate of diffusion of the fusion reaction products induced by oscillations in the continuous part of the spectrum, as estimated from the appropriate quasi-linear theory, is found to be significantly smaller than could be expected if normal modes (i.e., nonconvective solutions) were excited. However, a relatively wide intermediate region is identified where opalescent fluctuations, capable of achieving significant amplitudes and corresponding to a quasi-discrete spectrum, can be excited

An experimentally validated bimorph cantilever model for piezoelectric energy harvesting from base excitations

International Nuclear Information System (INIS)

Erturk, A; Inman, D J

2009-01-01

Piezoelectric transduction has received great attention for vibration-to-electric energy conversion over the last five years. A typical piezoelectric energy harvester is a unimorph or a bimorph cantilever located on a vibrating host structure, to generate electrical energy from base excitations. Several authors have investigated modeling of cantilevered piezoelectric energy harvesters under base excitation. The existing mathematical modeling approaches range from elementary single-degree-of-freedom models to approximate distributed parameter solutions in the sense of Rayleigh–Ritz discretization as well as analytical solution attempts with certain simplifications. Recently, the authors have presented the closed-form analytical solution for a unimorph cantilever under base excitation based on the Euler–Bernoulli beam assumptions. In this paper, the analytical solution is applied to bimorph cantilever configurations with series and parallel connections of piezoceramic layers. The base excitation is assumed to be translation in the transverse direction with a superimposed small rotation. The closed-form steady state response expressions are obtained for harmonic excitations at arbitrary frequencies, which are then reduced to simple but accurate single-mode expressions for modal excitations. The electromechanical frequency response functions (FRFs) that relate the voltage output and vibration response to translational and rotational base accelerations are identified from the multi-mode and single-mode solutions. Experimental validation of the single-mode coupled voltage output and vibration response expressions is presented for a bimorph cantilever with a tip mass. It is observed that the closed-form single-mode FRFs obtained from the analytical solution can successfully predict the coupled system dynamics for a wide range of electrical load resistance. The performance of the bimorph device is analyzed extensively for the short circuit and open circuit resonance

Numerical and experimental study of Ti6Al4V components manufactured using powder bed fusion additive manufacturing

OpenAIRE

Zielinski, J.; Mindt, H.-W.; Düchting, J.; Schleifenbaum, J.H.; Megahed, M.

2017-01-01

Powder bed fusion additive manufacturing of titanium alloys is an interesting manufacturing route for many applications requiring high material strength combined with geometric complexity. Managing powder bed fusion challenges, including porosity, surface finish, distortions and residual stresses of as-built material, is the key to bringing the advantages of this process to production main stream. This paper discusses the application of experimental and numerical analysis towards optimizing t...

Experimental and evaluated data on the discrete level excitation function of the 238U(n,n') reaction

International Nuclear Information System (INIS)

Simakov, S.P.

1991-01-01

Experimental data on the 238 U excitation function are compiled and analyzed. The experimental data are compared with the evaluated data from the BNAB, ENDF/B-IV and ENDL-78 evaluated data libraries. It is shown that the BNAB evaluated data are in good agreement with the existing experimental data, including new results from recent experiments. (author). 26 refs, 2 figs, 2 tabs

Fusion hindrance for the positive Q -value system 12C+30Si

Science.gov (United States)

Montagnoli, G.; Stefanini, A. M.; Jiang, C. L.; Hagino, K.; Galtarossa, F.; Colucci, G.; Bottoni, S.; Broggini, C.; Caciolli, A.; Čolović, P.; Corradi, L.; Courtin, S.; Depalo, R.; Fioretto, E.; Fruet, G.; Gal, A.; Goasduff, A.; Heine, M.; Hu, S. P.; Kaur, M.; Mijatović, T.; Mazzocco, M.; Montanari, D.; Scarlassara, F.; Strano, E.; Szilner, S.; Zhang, G. X.

2018-02-01

Background: The fusion reaction 12C+30Si is a link between heavier cases studied in recent years, and the light heavy-ion systems, e.g., 12C+12C , 16O+16O that have a prominent role in the dynamics of stellar evolution. 12C+30Si fusion itself is not a relevant process for astrophysics, but it is important to establish its behavior below the barrier, where couplings to low-lying collective modes and the hindrance phenomenon may determine the cross sections. The excitation function is presently completely unknown below the barrier for the 12C+30Si reaction, thus no reliable extrapolation into the astrophysical regime for the C+C and O+O cases can be performed. Purpose: Our aim was to carry out a complete measurement of the fusion excitation function of 12C+30Si from well below to above the Coulomb barrier, so as to clear up the consequence of couplings to low-lying states of 30Si, and whether the hindrance effect appears in this relatively light system which has a positive Q value for fusion. This would have consequences for the extrapolated behavior to even lighter systems. Methods: The inverse kinematics was used by sending 30Si beams delivered from the XTU Tandem accelerator of INFN-Laboratori Nazionali di Legnaro onto thin 12C (50 μ g /cm2 ) targets enriched to 99.9 % in mass 12. The fusion evaporation residues (ER) were detected at very forward angles, following beam separation by means of an electrostatic deflector. Angular distributions of ER were measured at Ebeam=45 , 59, and 80 MeV, and they were angle integrated to derive total fusion cross sections. Results: The fusion excitation function of 12C+30Si was measured with high statistical accuracy, covering more than five orders of magnitude down to a lowest cross section ≃3 μ b . The logarithmic slope and the S factor have been extracted and we have convincing phenomenological evidence of the hindrance effect. These results have been compared with the calculations performed within the model that

Fusion neutronics

CERN Document Server

Wu, Yican

2017-01-01

This book provides a systematic and comprehensive introduction to fusion neutronics, covering all key topics from the fundamental theories and methodologies, as well as a wide range of fusion system designs and experiments. It is the first-ever book focusing on the subject of fusion neutronics research. Compared with other nuclear devices such as fission reactors and accelerators, fusion systems are normally characterized by their complex geometry and nuclear physics, which entail new challenges for neutronics such as complicated modeling, deep penetration, low simulation efficiency, multi-physics coupling, etc. The book focuses on the neutronics characteristics of fusion systems and introduces a series of theories and methodologies that were developed to address the challenges of fusion neutronics, and which have since been widely applied all over the world. Further, it introduces readers to neutronics design’s unique principles and procedures, experimental methodologies and technologies for fusion systems...

Core excitation and de-excitation spectroscopies of free atoms and molecules

International Nuclear Information System (INIS)

Ueda, Kiyoshi

2006-01-01

This article provides a review of the current status of core excitation and de-excitation spectroscopy studies of free atoms molecules using a high-resolution soft X-ray monochromator and a high-resolution electron energy analyzer, installed in the soft X-ray photochemistry beam line at SPring-8. Experimental results are discussed for 1s excitation of Ne, O 1s excitation of CO and H 2 O, and F 1s excitation of CF 4 . (author)

Influence of mass asymmetry in fusion cross section of intermediate weight ions

International Nuclear Information System (INIS)

Anjos, R.M. dos.

1987-01-01

The mass asymmetry degree effect on fusion, was investigated for different systems involving nucleus A projectie , A target ≤ 40, populating a compound nucleus. The following systems were studied: ( 19 F + 19 F), ( 12 C + 26 Mg) and ( 19 F + 12 C, 16 O, 27 Al, 40 Ca) in the energy range of 32 ≤ E lab ≤ 72 MeV and angular range 6 0 ≤ Θ lab ≤ 28 0 . The experimental method employed the time of flight technique, of the evaporation residuals. Analysis of excitation function indicate different behavior for symmetric and asymmetric systems suggesting that the presence of other more competitive processes is more pronounced in asymmetric entrance channels at high energies. These behaviors indicate that mass asymmetry is an important point in complete and incomplete fusion processes. (A.C.A.S.) [pt

General description of preliminary design of an experimental fusion reactor and the future problems

International Nuclear Information System (INIS)

Sako, Kiyoshi

1976-01-01

Recently, the studies on plasma physics has progressed rapidly, and promising experimental data emerged successively. Especially expectation mounts high that Tokamak will develop into power reactors. In Japan, the construction of large plasma devices such as JT-60 of JAERI is going to start, and after several years, the studies on plasma physics will come to the end of first stage, then the main research and development will be directed to power reactors. The studies on the design of practical fusion reactors have been in progress since 1973 in JAERI, and the preliminary design is being carried out. The purposes of the preliminary design are the clarification of the concept of the experimental reactor and the requirements for the studies on core plasma, the examination of the problems for developing main components and systems of the reactor, and the development of design technology. The experimental reactor is the quasi-steady reactor of 100 MW fusion reaction output, and the conditions set for the design and the basis of their setting are explained. The outline of the design, namely core plasma, blankets, superconductive magnets and the shielding with them, vacuum wall, neutral particle injection heating device, core fuel supply and exhaust system, and others, is described. In case of scale-up the reactor structural material which can withstand neutron damage must be developed. (Kako, I.)

Coupled-channel calculation for cross section of fusion and barrier distribution of {}^{16,17,18}O + {}^{16}O reactions

Science.gov (United States)

Fereidonnejad, R.; Sadeghi, H.; Ghambari, M.

2018-03-01

In this work, the effect of multi-phonon excitation on heavy-ion fusion reactions has been studied and fusion barrier distributions of energy intervals near and below the Coulomb barrier have been studied for 16,17,18O + 16O reactions. The structure and deformation of nuclear projectiles have been studied. Given the adaptation of computations to experimental data, our calculations predict the behavior of reactions in intervals of energy in which experimental measurements are not available. In addition the S-factor for these reactions has been calculated. The results showed that the structure and deformation of a nuclear projectile are important factors. The S-factor, obtained in the coupled-channel calculations for the {}^{16}O + {}^{16}O, {}^{17}O +{}^{16}O and {}^{18}O +{}^{16}O reactions, showed good agreement with the experimental data and had a maximum value at an energy near 5, 4.5 and 4 MeV, respectively.

Canada's Fusion Program

International Nuclear Information System (INIS)

Jackson, D. P.

1990-01-01

Canada's fusion strategy is based on developing specialized technologies in well-defined areas and supplying these technologies to international fusion projects. Two areas are specially emphasized in Canada: engineered fusion system technologies, and specific magnetic confinement and materials studies. The Canadian Fusion Fuels Technology Project focuses on the first of these areas. It tritium and fusion reactor fuel systems, remote maintenance and related safety studies. In the second area, the Centre Canadian de fusion magnetique operates the Tokamak de Varennes, the main magnetic fusion device in Canada. Both projects are partnerships linking the Government of Canada, represented by Atomic Energy of Canada Limited, and provincial governments, electrical utilities, universities and industry. Canada's program has extensive international links, through which it collaborates with the major world fusion programs, including participation in the International Thermonuclear Experimental Reactor project

The Measurement of the Evaporation Residues Excitation Functions in the Fusion Reactions 144Sm (40Ar,xn) and 166Er(40Ar,xn)

Science.gov (United States)

Chernysheva, E. V.; Rodin, A. M.; Belozerov, A. V.; Dmitriev, S. N.; Gulyaev, A. V.; Gulyaeva, A. V.; Itkis, M. G.; Novoselov, A. S.; Oganessian, Yu. Ts.; Salamatin, V. S.; Stepantsov, S. V.; Vedeneev, V. Yu.; Yukhimchuk, S. A.; Krupa, L.; Kliman, J.; Motycak, S.; Sivacek, I.

2015-06-01

The evaporation residues excitation functions for the reactions 40Ar+144Sm→184Hg and 40Ar+166Er→206Rn were measured at the energies below and above the Coulomb barrier (Elab=142-207 MeV) using a mass-separator MASHA. The experimental data were compared with theoretical calculations using a Channel Coupling Model. The influence of experimental beam energy spread on the excitation functions was taking into account. It was found that structure of xn-cross sections correlate strongly with the nuclear structure of colliding nuclei.

Excitation of autoionizing states of helium by 100 keV proton impact: II. Excitation cross sections and mechanisms of excitation

Energy Technology Data Exchange (ETDEWEB)

Godunov, A.L. [Department of Physics, Tulane University, New Orleans, LA 70118-5698 (United States); Ivanov, P.B.; Schipakov, V.A. [Troitsk Institute of Innovation and Fusion Research Troitsk, Moscow region, 142092 (Russian Federation); Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A. [Laboratoire Collisions, Agregats, Reactivite, IRSAMC, UMR 5589, CNRS-Universite Paul Sabatier, 31062 Toulouse Cedex (France)

2000-03-14

Mechanisms of two-electron excitation of the (2s{sup 2}){sup 1} S, (2p{sup 2} ){sup 1} D and (2s2p){sup 1} P autoionizing states of helium are studied both experimentally and theoretically. It is shown that an explicit introduction of a kinematic factor, with a process-specific phase leads to a productive parametrization of experimental cross sections of ionization, allowing one to extract cross sections of excitation of autoionizing states. Using a new fitting procedure together with the proposed parametrization made it possible to obtain the excitation cross sections and magnetic sublevel population from electron spectra as well as, for the first time, to resolve the contribution of resonance and interference components to resonance profiles. Interference with direct ionization is shown to contribute significantly into resonance formation even for backward ejection angles. We demonstrate theoretically that the excitation cross sections thus extracted from experimental electron spectra hold information about the interaction of autoionizing states with an adjacent continuum. (author)

Electron-beam-excited gas laser research

International Nuclear Information System (INIS)

Johnson, A.W.; Gerardo, J.B.; Patterson, E.L.; Gerber, R.A.; Rice, J.K.; Bingham, F.W.

1975-01-01

Net energy gain in laser fusion places requirements on the laser that are not realized by any existing laser. Utilization of relativistic electron beams (REB's), a relatively new source for the excitation of gas laser media, may lead to new lasers that could satisfy these requirements. Already REB's have been utilized to excite gas laser media and produce gas lasers that have not been produced as successfully any other way. Electron-beam-excitation has produced electronic-transition dimer lasers that have not yet been produced by any other excitation scheme (for example, Xe 2 / sup *(1)/, Kr:O(2 1 S)/sup 2/, KrF/sup *(3)/). In addition, REB's have initiated chemical reactions to produce HF laser radiation with unique and promising results. Relativistic-electron-beam gas-laser research is continuing to lead to new lasers with unique properties. Results of work carried out at Sandia Laboratories in this pioneering effort of electron-beam-excited-gas lasers are reviewed. (U.S.)

Source term evaluation for accident transients in the experimental fusion facility ITER

Energy Technology Data Exchange (ETDEWEB)

Virot, F.; Barrachin, M.; Cousin, F. [IRSN, BP3-13115, Saint Paul lez Durance (France)

2015-03-15

We have studied the transport and chemical speciation of radio-toxic and toxic species for an event of water ingress in the vacuum vessel of experimental fusion facility ITER with the ASTEC code. In particular our evaluation takes into account an assessed thermodynamic data for the beryllium gaseous species. This study shows that deposited beryllium dusts of atomic Be and Be(OH){sub 2} are formed. It also shows that Be(OT){sub 2} could exist in some conditions in the drain tank. (authors)

Measurements of fusion cross section for 12C +63,65 Cu systems

International Nuclear Information System (INIS)

Rocha, C.A. da.

1987-01-01

Cross-section measurements for nuclear fusion in the 12 C+ 63.65 Cu system, at 12 C energy range from 0.9 to 1.8 times the Coulomb barrier are presented. In order to detect and to obtain the mass identification of the evaporation residues following the fusion process, the time of flight method was adopted in conjunction with an eletrostatic deflector capable of separating the evaporation residues from the beam particles. The limitation and advantadges of this method of measurement are discussed. The excitation functions were analysed using the unidimensional barrier penetration model with different nuclear potentials. Theoretical fusion cross-section values obtained from this analysis were systematically smaller than our measured values, in the energy region below the Coulomb barrier. In order to discover which channel enhances the fusion cross-section in this region, a coupled channel calculation was performed, with the CCFUS code. The experimental data for the above reactions were compared with the systems 16.18 O+ 63.65 Cu, measured by our group. In this comparison, it was noted that the systems 12 C+ 63.65 Cu, have greater fusion cross section below the Coulomb barrier. The comparison of velocity spectra of the evaporated residues for the two systems shows that 12 C+ 63 Cu has a strong reaction channel that was not present in the 12 C+ 65 Cu system. (author) [pt

Generation of thermonuclear fusion neutrons by means of a pure explosion. Part 2. Experimental results

International Nuclear Information System (INIS)

Derentowicz, H.; Kaliski, S.; Wolski, J.; Ziolkowski, Z.

1977-01-01

This paper presents the experimental results of the generation of a thermonuclear fusion neutrons by means of explosion. The experimental set is based on a quasi-spherical experiment in which a polyethylene layer is shot into a conic region hollowed out in a golden target and filled with deuterium gas. The speeding-up system is based on shooting the conic liner onto the surface of the Cu cone in which the Mach wave is generated and propagates along the cone axis leading to an implosion velocity of the polyethylene layer of the order of (4 - 5).10 6 cm/s. This affords a 10 3 -multiple compression of the D 2 gas (p 0 approximately 1.2 atm) and a neutron emission of the order of 3.10 7 from a mass of about 10 -7 g. This result is in full agreement with theoretical estimates. This is the first published and documented experiment in which a neutron stream of thermonuclear fusion was obtained by means of a pure explosion. (author)

Fusion Physics

Energy Technology Data Exchange (ETDEWEB)

Kikuchi, Mitsuru; Lackner, Karl; Tran, Minh Quang [eds.

2012-09-15

Recreating the energy production process of the Sun - nuclear fusion - on Earth in a controlled fashion is one of the greatest challenges of this century. If achieved at affordable costs, energy supply security would be greatly enhanced and environmental degradation from fossil fuels greatly diminished. Fusion Physics describes the last fifty years or so of physics and research in innovative technologies to achieve controlled thermonuclear fusion for energy production. The International Atomic Energy Agency (IAEA) has been involved since its establishment in 1957 in fusion research. It has been the driving force behind the biennial conferences on Plasma Physics and Controlled Thermonuclear Fusion, today known as the Fusion Energy Conference. Hosted by several Member States, this biennial conference provides a global forum for exchange of the latest achievements in fusion research against the backdrop of the requirements for a net energy producing fusion device and, eventually, a fusion power plant. The scientific and technological knowledge compiled during this series of conferences, as well as by the IAEA Nuclear Fusion journal, is immense and will surely continue to grow in the future. It has led to the establishment of the International Thermonuclear Experimental Reactor (ITER), which represents the biggest experiment in energy production ever envisaged by humankind.

Fusion reactors - types - problems

International Nuclear Information System (INIS)

Schmitter, K.H.

1979-07-01

A short account is given of the principles of fusion reactions and of the expected advantages of fusion reactors. Descriptions are presented of various Tokamak experimental devices being developed in a number of countries and of some mirror machines. The technical obstacles to be overcome before a fusion reactor could be self-supporting are discussed. (U.K.)

An Experimental and Theoretical Investigation of a Micromirror Under Mixed-Frequency Excitation

KAUST Repository

Ilyas, Saad; Ramini, Abdallah; Carreno, Armando Arpys Arevalo; Younis, Mohammad I.

2015-01-01

We present an experimental and theoretical investigation of a micromachined mirror under a mixed-frequency signal composed of two harmonic ac sources. The micromirror is made of polyimide as the main structural layer. The experimental and theoretical dynamics are explored via frequency sweeps in the desired neighborhoods. One frequency is fixed while the other frequency is swept through a wide range to study the dynamic responses. To simulate the behavior of the micromirror, it is modeled as a single degree of freedom system, where the parameters of the model are extracted experimentally. A good agreement is reported among the simulation results and the experimental data. These responses are studied under different frequencies and input voltages. The results show interesting dynamics, where the system exhibits primary resonance and combination resonances of additive and subtractive type. The mixed excitation is demonstrated as a way to increase the bandwidth of the resonator near primary resonance, which can be promising for resonant sensing applications in the effort to increase the signal-noise ratio over extended frequency range.

An Experimental and Theoretical Investigation of a Micromirror Under Mixed-Frequency Excitation

KAUST Repository

Ilyas, Saad

2015-01-12

We present an experimental and theoretical investigation of a micromachined mirror under a mixed-frequency signal composed of two harmonic ac sources. The micromirror is made of polyimide as the main structural layer. The experimental and theoretical dynamics are explored via frequency sweeps in the desired neighborhoods. One frequency is fixed while the other frequency is swept through a wide range to study the dynamic responses. To simulate the behavior of the micromirror, it is modeled as a single degree of freedom system, where the parameters of the model are extracted experimentally. A good agreement is reported among the simulation results and the experimental data. These responses are studied under different frequencies and input voltages. The results show interesting dynamics, where the system exhibits primary resonance and combination resonances of additive and subtractive type. The mixed excitation is demonstrated as a way to increase the bandwidth of the resonator near primary resonance, which can be promising for resonant sensing applications in the effort to increase the signal-noise ratio over extended frequency range.

Electron capture into excited states of multi-charged ions

International Nuclear Information System (INIS)

Dijkkamp, D.

1985-01-01

This thesis deals with charge exchange reactions in slow collisions of multi-charged ions with neutral atoms or molecules. These reactions proceed very efficiently via a curve crossing mechanism, which leads to preferential population of excited states of the ion. The subsequent decay of these states leads to the emission of characteristic radiation. From wavelength resolved measurements of the absolute intensity of this radiation, cross sections for selective population of the excited (n,l-) states of the ion were determined. In addition, for some systems the total capture cross section was measured directly by means of charge state analysis of the secondary projectile ions. The role of charge exchange processes in fusion plasmas and in astrophysical plasmas is indicated. An experimental set-up is described with emphasis on the Electron Cyclotron Resonance Ion Source that was used in the experiments. Results for collisions of C 6+ , N 6+ , O 6+ and Ne 6+ with He, H 2 and Ar are presented as well as for electron capture from Li atoms by C 4+ and He 2+ . The interaction of the iso-electronic sequence C 4+ , N 5+ , O 6+ with atomic hydrogen, molecular hydrogen and helium is studied. First results for partial and total cross sections in collisions of fully stripped carbon, nitrogen and oxygen ions with atomic hydrogen are presented. These data are of particular importance for applications in fusion diagnostics. The data indicate that calculations of both molecular and atomic orbital type yield correct results, if an extended basis set is used. (Auth.)

Hyperenhanced Li - Li Chemonuclear Fusion

International Nuclear Information System (INIS)

Ikegami, Hidetsugu

2006-01-01

A new fusion scheme, the Li - Li chemonuclear fusion is presented, where nuclear fusion reactions are linked to atomic fusion reactions. Lithium ions are implanted on a surface of metallic Li liquid at an energy of nuclear stopping (several keV/amu). The ions collide slowly with liquid Li atoms without electronic excitation and lead to the Li - Li chemonuclear fusion through the formation of united atoms or quasi-C atoms at their turning points. Inside the quasi-atoms twin nuclei are confined within respective sub-pm scale spheres of zero-point oscillation and form themselves into ultradense intermediate nuclear complexes. Their density is million times as large as the solar interior density and close to densities of white dwarfs or white-dwarf progenitors of supernovae. This confinement of nuclear complexes is enormously prolonged towards the pycno-nuclear reactions induced by the zero-point oscillation under the presence of thermodynamic force specified by the Gibbs energy change in the quasi-atom formation in the liquid. Resulted rate enhancement of nuclear fusion by a factor of 10 48 has been anticipated. The enhancement is also argued in connection with the Bose-Einstein condensation

Peaceful fusion

Energy Technology Data Exchange (ETDEWEB)

Englert, Matthias [IANUS, TU Darmstadt (Germany)

2014-07-01

Like other intense neutron sources fusion reactors have in principle a potential to be used for military purposes. Although the use of fissile material is usually not considered when thinking of fusion reactors (except in fusion-fission hybrid concepts) quantitative estimates about the possible production potential of future commercial fusion reactor concepts show that significant amounts of weapon grade fissile materials could be produced even with very limited amounts of source materials. In this talk detailed burnup calculations with VESTA and MCMATH using an MCNP model of the PPCS-A will be presented. We compare different irradiation positions and the isotopic vectors of the plutonium bred in different blankets of the reactor wall with the liquid lead-lithium alloy replaced by uranium. The technical, regulatory and policy challenges to manage the proliferation risks of fusion power will be addressed as well. Some of these challenges would benefit if addressed at an early stage of the research and development process. Hence, research on fusion reactor safeguards should start as early as possible and accompany the current research on experimental fusion reactors.

Manipulator system for remote maintenance of fusion experimental reactor

International Nuclear Information System (INIS)

Shibanuma, Kiyoshi; Munakata, Tadashi; Murakami, Shin; Kondoh, Mitsunori.

1991-01-01

We have completed the conceptual design for a rail-mounted vehicle type remote maintenance system for the fusion experimental reactor (FER), which will be the first D-T burning reactor in Japan. We have fabricated a 1/5-scale model and confirmed the feasibility of the design. In this system, a rail is deployed into the vessel and supported at four horizontal ports. A vehicle then moves along the rail and handles in-vessel components with manipulators. The advantages of this concept are the high stiffness and high reliability of the rail, and the high mobility of the vehicle for efficient maintenance operations. In the FER, this concept is considered to be the first option for in-vessel maintenance. This paper describes the conceptual design of the system and the feasibility study using the 1/5-scale model. (author)

Excited charmed mesons

International Nuclear Information System (INIS)

Butler, J.N.; Shukla, S.

1995-05-01

The experimental status of excited charmed mesons is reviewed and is compared to theoretical expectations. Six states have been observed and their properties are consistent with those predicted for excited charmed states with orbital angular momentum equal to one

Gene Fusion Markup Language: a prototype for exchanging gene fusion data.

Science.gov (United States)

Kalyana-Sundaram, Shanker; Shanmugam, Achiraman; Chinnaiyan, Arul M

2012-10-16

An avalanche of next generation sequencing (NGS) studies has generated an unprecedented amount of genomic structural variation data. These studies have also identified many novel gene fusion candidates with more detailed resolution than previously achieved. However, in the excitement and necessity of publishing the observations from this recently developed cutting-edge technology, no community standardization approach has arisen to organize and represent the data with the essential attributes in an interchangeable manner. As transcriptome studies have been widely used for gene fusion discoveries, the current non-standard mode of data representation could potentially impede data accessibility, critical analyses, and further discoveries in the near future. Here we propose a prototype, Gene Fusion Markup Language (GFML) as an initiative to provide a standard format for organizing and representing the significant features of gene fusion data. GFML will offer the advantage of representing the data in a machine-readable format to enable data exchange, automated analysis interpretation, and independent verification. As this database-independent exchange initiative evolves it will further facilitate the formation of related databases, repositories, and analysis tools. The GFML prototype is made available at http://code.google.com/p/gfml-prototype/. The Gene Fusion Markup Language (GFML) presented here could facilitate the development of a standard format for organizing, integrating and representing the significant features of gene fusion data in an inter-operable and query-able fashion that will enable biologically intuitive access to gene fusion findings and expedite functional characterization. A similar model is envisaged for other NGS data analyses.

Research into thermonuclear fusion

International Nuclear Information System (INIS)

Schumacher, U.

1989-01-01

The experimental and theoretical studies carried out in close international cooperation in the field of thermonuclear fusion by magnetic plasma confinement have achieved such progress towards higher plasma temperatures and densities, longer confinement times and, thus, increased fusion product, that emphasis now begins to be shifted from problems of physics to those of technology as a next major step is being prepared towards a large international project (ITER) to achieve thermonuclear burning. The generation and maintenance of a burning fusion plasma in an experimental physics phase will be followed by a phase of technical materials studies at high fluxes of fusion neutrons. These goals have been pursued since 1983 by an international study group at Garching working on the design of a Next European Torus (NET). Since May 1988, an international study group comprising ten experts each from the USSR, USA, Japan, and the European Community has begun to work on a design draft of ITER (International Thermonuclear Experimental Reactor) in Garching under the auspices of IAEA. (orig.) [de

C+C Fusion Cross Sections Measurements for Nuclear Astrophysics

International Nuclear Information System (INIS)

Almaraz-Calderon, S.; Carnelli, P. F. F.; Rehm, K. E.; Albers, M.; Alcorta, M.; Bertone, P. F.; Digiovine, B.; Esbensen, H.; Fernandez Niello, J. O.; Jiang, C. L.; Lai, J.; Nusair, O.; Palchan-Hazan, T.; Pardo, R. C.; Paul, M.; Giardina, G.; Eidelman, S.; Venanzoni, G.; Battaglieri, M.; Mandaglio, G.

2015-01-01

Total fusion cross section of carbon isotopes were obtained using the newly developed MUSIC detector. MUSIC is a highly efficient, active target-detector system designed to measure fusion excitation functions with radioactive beams. The present measurements are relevant for understanding x-ray superbursts. The results of the first MUSIC campaign as well as the astrophysical implications are presented in this work

C+C Fusion Cross Sections Measurements for Nuclear Astrophysics

Science.gov (United States)

Almaraz-Calderon, S.; Carnelli, P. F. F.; Rehm, K. E.; Albers, M.; Alcorta, M.; Bertone, P. F.; Digiovine, B.; Esbensen, H.; Fernandez Niello, J. O.; Henderson, D.; Jiang, C. L.; Lai, J.; Marley, S. T.; Nusair, O.; Palchan-Hazan, T.; Pardo, R. C.; Paul, M.; Ugalde, C.

2015-06-01

Total fusion cross section of carbon isotopes were obtained using the newly developed MUSIC detector. MUSIC is a highly efficient, active target-detector system designed to measure fusion excitation functions with radioactive beams. The present measurements are relevant for understanding x-ray superbursts. The results of the first MUSIC campaign as well as the astrophysical implications are presented in this work.

Advanced lasers for fusion

International Nuclear Information System (INIS)

Krupke, W.F.; George, E.V.; Haas, R.A.

1979-01-01

Laser drive systems' performance requirements for fusion reactors are developed following a review of the principles of inertial confinement fusion and of the technical status of fusion research lasers (Nd:glass; CO 2 , iodine). These requirements are analyzed in the context of energy-storing laser media with respect to laser systems design issues: optical damage and breakdown, medium excitation, parasitics and superfluorescence depumping, energy extraction physics, medium optical quality, and gas flow. Three types of energy-storing laser media of potential utility are identified and singled out for detailed review: (1) Group VI atomic lasers, (2) rare earth solid state hybrid lasers, and (3) rare earth molecular vapor lasers. The use of highly-radiative laser media, particularly the rare-gas monohalide excimers, are discussed in the context of short pulse fusion applications. The concept of backward wave Raman pulse compression is considered as an attractive technique for this purpose. The basic physics and device parameters of these four laser systems are reviewed and conceptual designs for high energy laser systems are presented. Preliminary estimates for systems efficiencies are given. (Auth.)

Fusion pumped laser

Science.gov (United States)

Pappas, D.S.

1987-07-31

The apparatus of this invention may comprise a system for generating laser radiation from a high-energy neutron source. The neutron source is a tokamak fusion reactor generating a long pulse of high-energy neutrons and having a temperature and magnetic field effective to generate a neutron flux of at least 10/sup 15/ neutrons/cm/sup 2//center dot/s. Conversion means are provided adjacent the fusion reactor at a location operable for converting the high-energy neutrons to an energy source with an intensity and energy effective to excite a preselected lasing medium. A lasing medium is spaced about and responsive to the energy source to generate a population inversion effective to support laser oscillations for generating output radiation. 2 figs., 2 tabs.

Some considerations on a plasma in the JAERI experimental fusion reactor

International Nuclear Information System (INIS)

Tone, T.; Yamato, H.; Maki, K.

1976-01-01

The preliminary analysis of the plasma characteristics for the JAERI tokamak experimental fusion reactor is reported. In order to make the reactor compact, the self-sustaining condition has been removed. Stationary heating by 200 keV neutral deuteron beam to maintain the power balance is applied expecting the power amplification by the TCT effect. The main parameters determined are power output of 100 MW, toroidal field on axis of 6 T, aspect ratio of 4.5 and major radius of 6.75 m. The results of the plasma power balance, fueling by means of the gas blanket scheme, power stabilization with feedback and the start-up are presented

Critical safety function guidelines for experimental fusion facilities

International Nuclear Information System (INIS)

Cadwallader, L.C.

1989-01-01

As fusion experiments proceed toward deuterium-tritium operation, more attention is being given to public safety. This paper presents the four classes of functions that fusion experiments must provide to assure safe, stable shutdown and retention of radionuclides. These functions are referred to as critical safety functions (CSFs). Selecting CSFs is an important step in probabilistic risk assessment (PRA). An example of CSF selection and usage for the Compact Ignition Tokamak (CIT) is also presented

Thought-shape fusion in anorexia nervosa: an experimental investigation.

Science.gov (United States)

Radomsky, Adam S; de Silva, Padmal; Todd, Gillian; Treasure, Janet; Murphy, Tara

2002-10-01

Cognitive biases and cognitive distortions have been implicated as important factors in the development and maintenance of many disorders. The concept of thought-shape fusion (TSF) in eating disorders was developed by Shafran, Teachman, Kerry, and Rachman (British Journal of Clinical Psychology 38 (1999) 167) as a variant of thought-action fusion, described by Shafran, Thordarson and Rachman (Journal of Anxiety Disorders 10 (1996) 379). TSF occurs when thinking about eating certain types of food increases a person's estimate of their shape and/or weight, elicits a perception of moral wrongdoing, and/or makes the person feel fat. Shafran et al. (1999) examined both the psychometric and experimental properties of TSF in an undergraduate sample. This paper reports an extension of this work to a clinical group (N=20) of patients with anorexia nervosa. After completing a set of relevant questionnaires, participants were asked to think about a food which they considered extremely fattening. They were then asked to write out the sentence, "I am eating--.", inserting the name of the fattening food in the blank. After being asked to rate their anxiety, guilt, feelings about their weight, morality, etc., participants were given the opportunity to neutralize their statement in any way they chose. The majority of the participants neutralized in ways consistent with the findings of Shafran et al. (1999). The results are discussed in terms of cognitive-behavioural formulations of eating disorders, and of the influence of cognitive biases and cognitive distortions on the processing of information relevant to food, weight and shape in anorexia nervosa.

Structural Transition and Antibody Binding of EBOV GP and ZIKV E Proteins from Pre-Fusion to Fusion-Initiation State

Directory of Open Access Journals (Sweden)

Anna Lappala

2018-05-01

Full Text Available Membrane fusion proteins are responsible for viral entry into host cells—a crucial first step in viral infection. These proteins undergo large conformational changes from pre-fusion to fusion-initiation structures, and, despite differences in viral genomes and disease etiology, many fusion proteins are arranged as trimers. Structural information for both pre-fusion and fusion-initiation states is critical for understanding virus neutralization by the host immune system. In the case of Ebola virus glycoprotein (EBOV GP and Zika virus envelope protein (ZIKV E, pre-fusion state structures have been identified experimentally, but only partial structures of fusion-initiation states have been described. While the fusion-initiation structure is in an energetically unfavorable state that is difficult to solve experimentally, the existing structural information combined with computational approaches enabled the modeling of fusion-initiation state structures of both proteins. These structural models provide an improved understanding of four different neutralizing antibodies in the prevention of viral host entry.

Lifetime and g-factor measurements of excited states using Coulomb excitation and alpha transfer reactions

Energy Technology Data Exchange (ETDEWEB)

Guevara, Z. E., E-mail: zjguevaram@unal.edu.co; Torres, D. A., E-mail: datorresg@unal.edu.co [Physics Department, Universidad Nacional de Colombia, Bogotá D.C. (Colombia)

2016-07-07

In this contribution the challenges in the use of a setup to simultaneously measure lifetimes and g-factor values will be presented. The simultaneous use of the transient field technique and the Doppler Shift Attenuation Method, to measure magnetic moments and lifetimes respectively, allows to obtain a complete characterization of the currents of nucleons and the deformation in excited states close to the ground state. The technique is at the moment limited to Coulomb excitation and alpha-transfer reactions, what opens an interesting perspective to consider this type of experiments with radioactive beams. The use of deep-inelastic and fusion-evaporation reactions will be discussed. An example of a setup that makes use of a beam of {sup 106}Cd to study excited states of {sup 110}Sn and the beam nuclei itself will be presented.

Fusion basis for lattice gauge theory and loop quantum gravity

Energy Technology Data Exchange (ETDEWEB)

Delcamp, Clement [Perimeter Institute for Theoretical Physics,31 Caroline Street North, Waterloo, Ontario N2L 2Y5 (Canada); Department of Physics Astronomy and Guelph-Waterloo Physics Institute, University of Waterloo,Waterloo, Ontario N2L 3G1 (Canada); Dittrich, Bianca; Riello, Aldo [Perimeter Institute for Theoretical Physics,31 Caroline Street North, Waterloo, Ontario N2L 2Y5 (Canada)

2017-02-10

We introduce a new basis for the gauge-invariant Hilbert space of lattice gauge theory and loop quantum gravity in (2+1) dimensions, the fusion basis. In doing so, we shift the focus from the original lattice (or spin-network) structure directly to that of the magnetic (curvature) and electric (torsion) excitations themselves. These excitations are classified by the irreducible representations of the Drinfel’d double of the gauge group, and can be readily “fused” together by studying the tensor product of such representations. We will also describe in detail the ribbon operators that create and measure these excitations and make the quasi-local structure of the observable algebra explicit. Since the fusion basis allows for both magnetic and electric excitations from the onset, it turns out to be a precious tool for studying the large scale structure and coarse-graining flow of lattice gauge theories and loop quantum gravity. This is in neat contrast with the widely used spin-network basis, in which it is much more complicated to account for electric excitations, i.e. for Gauß constraint violations, emerging at larger scales. Moreover, since the fusion basis comes equipped with a hierarchical structure, it readily provides the language to design states with sophisticated multi-scale structures. Another way to employ this hierarchical structure is to encode a notion of subsystems for lattice gauge theories and (2+1) gravity coupled to point particles. In a follow-up work, we have exploited this notion to provide a new definition of entanglement entropy for these theories.

Fusion basis for lattice gauge theory and loop quantum gravity

International Nuclear Information System (INIS)

Delcamp, Clement; Dittrich, Bianca; Riello, Aldo

2017-01-01

We introduce a new basis for the gauge-invariant Hilbert space of lattice gauge theory and loop quantum gravity in (2+1) dimensions, the fusion basis. In doing so, we shift the focus from the original lattice (or spin-network) structure directly to that of the magnetic (curvature) and electric (torsion) excitations themselves. These excitations are classified by the irreducible representations of the Drinfel’d double of the gauge group, and can be readily “fused” together by studying the tensor product of such representations. We will also describe in detail the ribbon operators that create and measure these excitations and make the quasi-local structure of the observable algebra explicit. Since the fusion basis allows for both magnetic and electric excitations from the onset, it turns out to be a precious tool for studying the large scale structure and coarse-graining flow of lattice gauge theories and loop quantum gravity. This is in neat contrast with the widely used spin-network basis, in which it is much more complicated to account for electric excitations, i.e. for Gauß constraint violations, emerging at larger scales. Moreover, since the fusion basis comes equipped with a hierarchical structure, it readily provides the language to design states with sophisticated multi-scale structures. Another way to employ this hierarchical structure is to encode a notion of subsystems for lattice gauge theories and (2+1) gravity coupled to point particles. In a follow-up work, we have exploited this notion to provide a new definition of entanglement entropy for these theories.

Cell Fusion along the Anterior-Posterior Neuroaxis in Mice with Experimental Autoimmune Encephalomyelitis.

Directory of Open Access Journals (Sweden)

Sreenivasa R Sankavaram

Full Text Available It is well documented that bone marrow-derived cells can fuse with a diverse range of cells, including brain cells, under normal or pathological conditions. Inflammation leads to robust fusion of bone marrow-derived cells with Purkinje cells and the formation of binucleate heterokaryons in the cerebellum. Heterokaryons form through the fusion of two developmentally differential cells and as a result contain two distinct nuclei without subsequent nuclear or chromosome loss.In the brain, fusion of bone marrow-derived cells appears to be restricted to the complex and large Purkinje cells, raising the question whether the size of the recipient cell is important for cell fusion in the central nervous system. Purkinje cells are among the largest neurons in the central nervous system and accordingly can harbor two nuclei.Using a well-characterized model for heterokaryon formation in the cerebellum (experimental autoimmune encephalomyelitis - a mouse model of multiple sclerosis, we report for the first time that green fluorescent protein-labeled bone marrow-derived cells can fuse and form heterokaryons with spinal cord motor neurons. These spinal cord heterokaryons are predominantly located in or adjacent to an active or previously active inflammation site, demonstrating that inflammation and infiltration of immune cells are key for cell fusion in the central nervous system. While some motor neurons were found to contain two nuclei, co-expressing green fluorescent protein and the neuronal marker, neuron-specific nuclear protein, a number of small interneurons also co-expressed green fluorescent protein and the neuronal marker, neuron-specific nuclear protein. These small heterokaryons were scattered in the gray matter of the spinal cord.This novel finding expands the repertoire of neurons that can form heterokaryons with bone marrow-derived cells in the central nervous system, albeit in low numbers, possibly leading to a novel therapy for spinal cord

Critical safety function guidelines for experimental fusion facilities

International Nuclear Information System (INIS)

Cadwallader, L.C.

1989-01-01

As fusion experiments proceed toward deuterium-tritium operation, more attention is being given to public safety. This paper presents the four classes of functions that fusion experiments must provide to assure safe, stable shutdown and retention of radionuclides. These functions are referred to as critical safety functions (CSFs). Selecting CSFs is an important step in probabilistic risk assessment (PRA). An example of CSF selection and usage for the Compact Ignition Tokamak (CIT) is also presented. 10 refs., 6 figs

Experimental Investigation of Muon-Catalyzed $dt$ Fusion in Wide Ranges of $D/T$ Mixture Conditions

CERN Document Server

Bom, V R; Demin, D L; van Eijk, C W E; Faifman, M P; Filchenkov, V V; Golubkov, A N; Grafov, N N; Grishenchkin, S K; Gritsaj, K I; Klevtsov, V G; Konin, A D; Kuryakin, A V; Medved', S V; Musyaev, R K; Perevozchikov, V V; Rudenko, A I; Sadetsky, S M; Vinogradov, Yu I; Yukhimchuk, A A; Yukhimchuk, S A; Zinov, V G; Zlatoustovskii, S V

2004-01-01

A vast program of the experimental investigation of muon-catalyzed $dt$ fusion was performed at the JINR Phasotron. Parameters of the $dt$ cycle were obtained in a wide range of $D/T$ mixture conditions: temperatures of $20\\div 800$ K, densities of $0.2\\div1.2$ LHD and tritium concentrations of $15\\div 86\\%$. The results obtained are summarized.

High-energy fusion: A quest for a simple, small and environmentally acceptable colliding-beam fusion power source

International Nuclear Information System (INIS)

Maglich, B.

1978-01-01

Fusion goals should be lowered for a speedier research and development of a less ambitious but a workable 'low-gain fusion power amplifier', based on proven technologies and concepts. The aim of the Migma Program of Controlled Fusion is a small (10-15 liters) fusion power source based on colliding beams instead of plasma or laser heating. Its scientific and technological 'philosophy' is radically different from that of the governmental fusion programs of the USA and USSR. Migmacell uses radiation-free fuels, ('advanced fuels'), rather than tritium. Economic projections show that such a smaller power cell can be econonomically competitive in spite of its low power gain, because it can be mass produced. Power stations could be made either large or small and the power transmission and distribution pattern in the nation would change. An interspersion of energy resources would result. Minifusion opens the possibility to smaller countries (and medium size institutions of large countries), for participation in fusion research; this resource of research talent is presently excluded from fusion by the high cost of the mainline governmental research (over $ 200 million for one experimental fusion device, as compared to $ 1 million for migmacell). The time-scale for obtaining experimental results is reduced from decades to years. Experimental accomplishments to date and the further research needed, are presented. (orig.) [de

Identification and selection of initiating events for experimental fusion facilities

International Nuclear Information System (INIS)

Cadwallader, L.C.

1989-01-01

This paper describes the current approaches used in probabilistic risk assessment (PRA) to identify and select accident initiating events for study in either probabilistic safety analysis or PRA. Current methods directly apply to fusion facilities as well as other types of industries, such as chemical processing and nuclear fission. These identification and selection methods include the Master Logic Diagram, historical document review, system level Failure Modes and Effects Analysis, and others. A combination of the historical document review, such as Safety Analysis Reports and fusion safety studies, and the Master Logic Diagram with appropriate quality assurance reviews, is suggested for standardizing US fusion PRA effects. A preliminary set of generalized initiating events applicable to fusion facilities derived from safety document review is presented as a framework to start from for the historical document review and Master Logic Diagram approach. Fusion designers should find this list useful for their design reviews. 29 refs., 2 tabs

Identification and selection of initiating events for experimental fusion facilities

International Nuclear Information System (INIS)

Cadwallader, L.C.

1989-01-01

This paper describes the current approaches used in probabilistic risk assessment (PRA) to identify and select accident initiating events for study in either probabilistic safety analysis or PRA. Current methods directly apply to fusion facilities as well as other types of industries, such as chemical processing and nuclear fission. These identification and selection methods include the Master Logic Diagram, historical document review, system level Failure Modes and Effects Analysis, and others. A combination of the historical document review, such as Safety Analysis Reports and fusion safety studies, and the Master Logic Diagram with appropriate quality assurance reviews, is suggested for standardizing U.S. fusion PRA efforts. A preliminary set of generalized initiating events applicable to fusion facilities derived from safety document review is presented as a framework to start from for the historical document review and Master Logic Diagram approach. Fusion designers should find this list useful for their design reviews. 29 refs., 1 tab

Fusion of Nonionic Vesicles

DEFF Research Database (Denmark)

Bulut, Sanja; Oskolkova, M. Z.; Schweins, R.

2010-01-01

We present an experimental study of vesicle fusion using light and neutron scattering to monitor fusion events. Vesicles are reproducibly formed with an extrusion procedure using an single amphiphile triethylene glycol mono-n-decyl ether in water. They show long-term stability for temperatures ar...... a barrier to fusion changing from 15 k(B)T at T = 26 degrees C to 10k(H) T at T = 35 degrees C. These results are compatible with the theoretical predictions using the stalk model of vesicle fusion....

World progress toward fusion energy

International Nuclear Information System (INIS)

Davies, N.A.

1989-01-01

The author discusses international progress in fusion research during the last three years. Much of the technical progress has been achieved through international collaboration in magnetic fusion research. This progress has stimulated political interest in a multinational effort, aimed at designing and possibly constructing the world's first experimental fusion reactor. This interest was reflected in recent summit-level discussions involving President Mitterand, General Secretary Gorbachev, and President Reagan. Most recently, the European Community (EC), Japan, the United States, and the U.S.S.R. have decided to begin serious preparation for taking the next step toward practical fusion energy. These parties have agreed to begin the design and supporting R and D for an International Thermonuclear Experimental Reactor (ITER) under the auspices of the International Atomic Energy Agency (IAEA). The initiation of this international program to prepare for a fusion test reactor is discussed

Excited states 2

CERN Document Server

Lim, Edward C

2013-01-01

Excited States, Volume 2 is a collection of papers that deals with molecules in the excited states. The book describes the geometries of molecules in the excited electronic states. One paper describes the geometries of a diatomic molecule and of polyatomic molecules; it also discusses the determination of the many excited state geometries of molecules with two, three, or four atoms by techniques similar to diatomic spectroscopy. Another paper introduces an ordered theory related to excitons in pure and mixed molecular crystals. This paper also presents some experimental data such as those invo

New results in low-energy fusion of 40Ca+Zr,9290

Science.gov (United States)

Stefanini, A. M.; Montagnoli, G.; Esbensen, H.; Čolović, P.; Corradi, L.; Fioretto, E.; Galtarossa, F.; Goasduff, A.; Grebosz, J.; Haas, F.; Mazzocco, M.; Soić, N.; Strano, E.; Szilner, S.

2017-07-01

Background: Near- and sub-barrier fusion of various Ca + Zr isotopic combinations have been widely investigated. A recent analysis of 40Ca+96Zr data has highlighted the importance of couplings to multiphonon excitations and to both neutron and proton transfer channels. Analogous studies of 40Ca+90Zr tend to exclude any role of transfer couplings. However, the lowest measured cross section for this system is rather high (840 μ b ). A rather complete data set is available for 40Ca+94Zr , while no measurement of 40Ca+92Zr fusion has been performed in the past. Purpose: Our aim is to measure the full excitation function of 40Ca+92Zr near the barrier and to extend downward the existing data on 40Ca+90Zr , in order to estimate the transfer couplings that should be used in coupled-channels calculations of the fusion of these two systems and of 40Ca+94Zr . Methods: 40Ca beams from the XTU Tandem accelerator of INFN-Laboratori Nazionali di Legnaro were used, bombarding thin metallic 90Zr (50 μ g /cm2 ) and 92ZrO2 targets (same thickness) enriched to 99.36 % and 98.06 % in masses 90 and 92, respectively. An electrostatic beam deflector allowed the detection of fusion evaporation residues (ER) at very forward angles, and angular distributions of ER were measured. Results: The excitation function of 40Ca+92Zr has been measured down to the level of ≃60 μ b . Coupled-channels (CC) calculations using a standard Woods-Saxon (WS) potential and following the line of a previous analysis of 40Ca+96Zr fusion data give a good account of the new data, as well as of the existing data for 40Ca+94Zr . The previous excitation function of 40Ca+90Zr has been extended down to 40 μ b . Conclusions: Transfer couplings play an important role in explaining the fusion data for 40Ca+92Zr and 40Ca+94Zr . The strength of the pair-transfer coupling is deduced by applying a simple recipe based on the value obtained for 40Ca+96Zr . The logarithmic slopes and the S factors for fusion are reproduced

International bulletin on atomic and molecular data for fusion. No. 18

International Nuclear Information System (INIS)

Katsonis, K.

1982-02-01

This bulletin deals with atomic and molecular data for fusion. A bibliography for the most recent data presented in the document is provided. Work in progress is briefly reported (electron impact excitation of hydrogen-like argon ions, excitation and charge transfer in collisions of Li atoms with alpha particles)

Effect of projectile structure on evaporation residue yields in incomplete fusion reactions

CERN Document Server

Babu, K S; Sudarshan, K; Shrivastava, B D; Goswami, A; Tomar, B S

2003-01-01

The excitation functions of heavy residues, representing complete and incomplete fusion products, produced in the reaction of sup 1 sup 2 C and sup 1 sup 3 C on sup 1 sup 8 sup 1 Ta have been measured over the projectile energy range of 5 to 6.5 MeV/nucleon by the recoil catcher method and off-line gamma-ray spectrometry. Comparison of the measured excitation functions with those calculated using the PACE2 code based on the statistical model revealed the occurrence of incomplete fusion reactions in the formation of alpha emission products. The fraction of incomplete fusion cross sections in the sup 1 sup 2 C + sup 1 sup 8 sup 1 Ta reaction was found to be higher, by a factor of approx 2, than that in the sup 1 sup 3 C + sup 1 sup 8 sup 1 Ta reaction. The results have been discussed in terms of the effect of alpha cluster structure of the projectile on incomplete fusion reactions.

Preliminary study on power balance in the plasma of an experimental fusion reactor

International Nuclear Information System (INIS)

Tone, Tatsuzo; Yamato, Harumi

1976-03-01

The preliminary study on power balance in the plasma is described in the first-stage design of an experimental fusion reactor. The purpose is to show the ranges of plasma parameters for the design output of about 100 MW with an injection power less than 50 MW. The impurity is permitted to the extent of Zsub(eff) -- 5 to meet the design requirement. Influences of the uncertainty in scaling law on the power output and injection power are discussed, and also possibility of the self-ignition. (auth.)

Theoretical and experimental study of the vibrational excitations in ethane monolayers adsorbed on graphite (0001) surfaces

DEFF Research Database (Denmark)

Hansen, Flemming Yssing; Taub, H.

1987-01-01

The collective vibrational excitations of two different crystalline monolayer phases of ethane (C2H6) adsorbed on the graphite (0001) surface have been investigated theoretically and experimentally. The monolayer phases studied are the commensurate 7/8 ×4 structure in which the ethane molecules lie...

Study of excitation energy dependence of nuclear level density parameter

International Nuclear Information System (INIS)

Mohanto, G.; Nayak, B.K.; Saxena, A.

2016-01-01

In the present study, we have populated CN by fusion reaction and excitation energy of the intermediate nuclei is determined after first chance α-emission to investigate excitation energy dependence of the NLD parameter. Evaporated neutron spectra were measured following alpha evaporation for obtaining NLD parameter for the reaction 11 B + 197 Au, populating CN 208 Po. This CN after evaporating an α-particle populates intermediate nucleus 204 Pb. The 204 Pb has magic number of Z=82. Our aim is to study the excitation energy dependence of NLD parameter for closed shell nuclei

Implications of fusion power plant studies for materials requirements

International Nuclear Information System (INIS)

Cook, Ian; Ward, David; Dudarev, Sergei

2002-01-01

This paper addresses the key requirements for fusion materials, as these have emerged from studies of commercial fusion power plants. The objective of the international fusion programme is the creation of power stations that will have very attractive safety and environmental features and viable economics. Fusion power plant studies have shown that these objectives may be achieved without requiring extreme advances in materials. But it is required that existing candidate materials perform at least as well as envisaged in the environment of fusion neutrons, heat fluxes and particle fluxes. The development of advanced materials would bring further benefits. The work required entails the investigation of many intellectually exciting physics issues of great scientific interest, and of wider application than fusion. In addition to giving an overview, selected aspects of the science, of particular physics interest, are illustrated

Influence of projectile α-breakup threshold on complete fusion

International Nuclear Information System (INIS)

Mukherjee, A.; Subinit Roy; Pradhan, M.K.; Saha Sarkar, M.; Basu, P.; Dasmahapatra, B.; Bhattacharya, T.; Bhattacharya, S.; Basu, S.K.; Chatterjee, A.; Tripathi, V.; Kailas, S.

2006-01-01

Complete fusion excitation functions for B11,10+Tb159 have been measured at energies around the respective Coulomb barriers, and the existing complete fusion measurements for Li7+Tb159 have been extended to higher energies. The measurements show significant reduction of complete fusion cross sections at above-barrier energies for both the reactions, B10+Tb159 and Li7+Tb159, when compared to those for B11+Tb159. The comparison shows that the extent of suppression of complete fusion cross sections is correlated with the α-separation energies of the projectiles. Also, the two reactions, B10+Tb159 and Li7+Tb159 were found to produce incomplete fusion products at energies near the respective Coulomb barriers, with the α-particle emitting channel being the favoured incomplete fusion process in both the cases

Heavy cluster in cold nuclear rearrangements in fusion and fission

International Nuclear Information System (INIS)

Armbruster, P.

1997-01-01

The experimental evidence for the appearance of cluster aspects in the dynamics of large rearrangements processes, as fusion and fission, is presented. Clusters in the sense as used in the following are strongly bound, doubly magic neutron rich nuclei as 48 Ca 28 , 78 Ni 50 , 132 Sn 82 , and 208 Pb 126 , the spherical nuclei Z=114 - 126 and N=184, and nuclei with closed shells N=28, 50, 82, and 126, and Z=28, 50, and 82. As with increasing nucleon numbers, the absolute shell corrections to the binding energies increase, the strongest effects are to be observed for the higher shells. The 132 cluster manifests itself in low energy fission (Faissner, H. and Wildermuth, K. Nucl. Phys., 58 (1964) 177). The 208 Pb cluster gave the new radioactivity (Rose, M.J. and Jones G.A., Nature, 307 (1984) 245) and the first superheavy elements (SHE) (Armbruster P., Ann. Rev. Nucl. Part. Sci., 35 (1985) 135-94; Munzenberg, G. Rep. Progr. Phys., 51 (1988) 57). The paper discuss experiments concerning the stability of clusters to intrinsic excitation energy in fusion and fission (Armbruster, P. Lect. Notes Phys., 158 (1982) 1). and the manifestation of clusters in the fusion entrance channel (Armbruster, P., J. Phys. Soc. Jpn., 58 (1989) 232). The importance of compactness of the clustering system seems to be equally decisive in fission and fusion. Finally, it s covered the importance of clusters for the production of SHEs)

An Experimental Investigation of the Dynamic Behavior of an In-Plane MEMS Shallow Arch Under Electrostatic Excitation

KAUST Repository

Ramini, Abdallah; Hafiz, Abdullah; Bellaredj, Mohammed Lamine Faycal; Al Hennawi, Qais M.; Younis, Mohammad I.

2016-01-01

We present experimental investigation of the nonlinear dynamics of a clamped-clamped in-plane MEMS shallow arch when excited by an electrostatic force. We explore the dynamic behaviors of the in-plane motion of the shallow arches via frequency

Building the US National Fusion Grid: results from the National Fusion Collaboratory Project

International Nuclear Information System (INIS)

Schissel, D.P.; Burruss, J.R.; Finkelstein, A.; Flanagan, S.M.; Foster, I.T.; Fredian, T.W.; Greenwald, M.J.; Johnson, C.R.; Keahey, K.; Klasky, S.A.; Li, K.; McCune, D.C.; Papka, M.; Peng, Q.; Randerson, L.; Sanderson, A.; Stillerman, J.; Stevens, R.; Thompson, M.R.; Wallace, G.

2004-01-01

The US National Fusion Collaboratory Project is developing a persistent infrastructure to enable scientific collaboration for all aspects of magnetic fusion research. The project is creating a robust, user-friendly collaborative software environment and making it available to more than 1000 fusion scientists in 40 institutions who perform magnetic fusion research in the United States. In particular, the project is developing and deploying a national Fusion Energy Sciences Grid (FusionGrid) that is a system for secure sharing of computation, visualization, and data resources over the Internet. The FusionGrid goal is to allow scientists at remote sites to fully participate in experimental and computational activities as if they were working at a common site thereby creating a virtual organization of the US fusion community. The project is funded by the USDOE Office of Science, Scientific Discovery through Advanced Computing (SciDAC) Program and unites fusion and computer science researchers to directly address these challenges

High energy resolution characteristics on 14MeV neutron spectrometer for fusion experimental reactor

Energy Technology Data Exchange (ETDEWEB)

Iguchi, Tetsuo [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.; Takada, Eiji; Nakazawa, Masaharu

1996-10-01

A 14MeV neutron spectrometer suitable for an ITER-like fusion experimental reactor is now under development on the basis of a recoil proton counter telescope principle in oblique scattering geometry. To verify its high energy resolution characteristics, preliminary experiments are made for a prototypical detector system. The comparison results show reasonably good agreement and demonstrate the possibility of energy resolution of 2.5% in full width at half maximum for 14MeV neutron spectrometry. (author)

Window of cold nuclear fusion and biased-pulse electrolysis experiment

International Nuclear Information System (INIS)

Takahashi, Akito; Jida, Toshiyuki; Maekawa, Fujio; Sugimoto, Hisashi; Yoshida, Shigeo

1989-01-01

Based on the electron screening effect and the excitation of deuteron harmonic oscillators in palladium lattice, theoretical aspects are given to explain the cold fusion phenomena and the possibility of nuclear heating. A narrow window is proposed to meet ≅ 10 watts per cubic centimeter for the nuclear heating, by the hypothetical excitation-screening model. A relatively wide window is feasible to meet a few fusion events per second per cc under the non-stationary conditions of deuteron-charging and discharging. For stationary lattice conditions, the probability of cold fusion is not feasible at all. To confirm the cold fusion phenomena, a heavy water electrolysis experiment was carried out using biased-pulse-electrolytic currents, expecting the enhancement of cold fusion events under charging and discharging of deuterons. For the neutron detection, a cross-checking system between a recoil-proton scintillation detector and a 3 He thermal neutron detector was employed to see coincident time-patterns of neutron emission from an electrolysis cell. To check the energy of emitted neutrons, pulse height spectrum of the recoil-proton detector was monitored. Up to the D-charging time of 300 hr, neutron yields of 1-2 n/s/cc were obtained for time-intervals of 60-200 hr. From the recoil-proton spectra, it was confirmed that 2.45 MeV neutrons by the D(d, n) 3 He fusion branch were emitted. The observed time-patterns of neutron emission suggest the existence of cold fusion under the charging and discharging conditions. (orig.)

Alternative Experimental Evidence for Chiral Restoration in Excited Baryons

International Nuclear Information System (INIS)

Glozman, L. Ya.

2007-01-01

It has been suggested that chiral symmetry is approximately restored in excited hadrons at zero temperature and density (effective symmetry restoration). Using very general chiral symmetry arguments, it is shown that those excited nucleons that are assumed from the spectroscopic patterns to be in approximate chiral multiplets must only weakly decay into the Nπ channel (f N*Nπ /f NNπ ) 2 NNπ . It turns out that for all those well-established excited nucleons which can be classified into chiral doublets the ratio is (f N*Nπ /f NNπ ) 2 ∼0.1 or much smaller for the high-spin states. In contrast, the only well-established excited nucleon for which the chiral partner cannot be identified from the spectroscopic data, N(1520), has a decay constant into the Nπ channel that is comparable with f NNπ

Thinking about the cold fusion fever

International Nuclear Information System (INIS)

Kitsunezaki, Akio

1989-01-01

The excitement since March 23 on cold fusion seems to be unprecedented evidence that the people of the world are waiting for fusion power with much enthusiasm. Cold fusion is really a surprise because it does not need high temperature and because it seems to be easy to enlarge the test tube into a useful power source if the claim by Professors Pons and Fleischmann at the University of Utah are true. The second announcement of cold fusion came from the Brigham Young University, also in the state of Utah, by Professor Jones, but his report was totally different from that given by Pons and Fleischmann. From the beginning of the 'fever', physicists have been very skeptical about cold fusion. Most of the critics and criticisms are targeted on Pons and Fleischmann rather than Jones, because not only was their paper poor but also their statements have not been scientific. They insisted that the heat came from fusion reaction, but without any scientific proof. They had not carried out the basic control experiment by running the same test with ordinary water instead of heavy water. A meeting on cold fusion was held at JAERI on May 15. At the end of the meeting, the some 260 attendants knew that cold fusion was not conceivable with the current scientific knowledge. (N.K.)

Experimental demonstration of tunable directional excitation of surface plasmon polaritons with a subwavelength metallic double slit

Science.gov (United States)

Li, Xiaowei; Tan, Qiaofeng; Bai, Benfeng; Jin, Guofan

2011-06-01

We demonstrate experimentally the directional excitation of surface plasmon polaritons (SPPs) on a metal film by a subwavelength double slit under backside illumination, based on the interference of SPPs generated by the two slits. By varying the incident angle, the SPPs can be tunably directed into two opposite propagating directions with a predetermined splitting ratio. Under certain incident angle, unidirectional SPP excitation can be achieved. This compact directional SPP coupler is potentially useful for many on-chip applications. As an example, we show the integration of the double-slit couplers with SPP Bragg mirrors, which can effectively realize selective coupling of SPPs into different ports in an integrated plasmonic chip.

Low energy incomplete fusion and its relevance to the synthesis of super heavy elements

Directory of Open Access Journals (Sweden)

Yadav Abhishek

2015-01-01

Full Text Available To study the presence of incomplete fusion at energies around the Coulomb-barrier and to understand its dependence on various entrance-channel parameters, the incomplete fusion fractions have been deduced (i from excitation function measurements for 18O,13,12C+159Tb, and (ii from forward recoil range measurements for 12C+159Tb systems, at low energies (<7MeV/A. The data have been analyzed within the framework of compound nucleus decay, which suggests the production of xn/pxn-channels via complete fusion, as these are found to be well reproduced by PACE4 predictions, while, a significant enhancement in the excitation functions of α-emitting channels has been observed over the theoretical ones, which has been attributed due to the incomplete fusion processes. Further, the incomplete fusion events observed in case of forward recoil ranges have been explained on the basis of the breakup fusion model, where these events may be attributed to the fusion of 8Be and/or 4He from 12C projectile to the target nucleus. For better insight into the underlying dynamics, the deduced fractions of incomplete fusion have been compared with other nearby systems as a function of various entrance channel parameters. The incomplete fusion has been found to be sensitive to the projectile’s energy and alpha-Q-value of the projectile.

Muon sticking factor in muon catalyzed fusion and the other aspect of this fusion process

International Nuclear Information System (INIS)

Takahashi, H.

1986-01-01

The effect of resonance nuclear fusion reaction on the initial muon sticking factor is formulated. The analysis shows that it is very sensitive to the resonance parameter, and the factor calculated, using the molecular wave function obtained by the Diffusion Monte Carlo method, is 0.1 +- 0.01 for the presently evaluated resonance parameter. The analysis of the multistep excitation effect on the reactivation factor shows that the effect is not so large, and the analysis of muonic x-ray spectra of μ 3 He from Pμd and dμd fusions is in good agreement with the values measured by Bossy et al

Fusion probability and survivability in estimates of heaviest nuclei production

Directory of Open Access Journals (Sweden)

Sagaidak Roman N.

2012-02-01

Full Text Available Production of the heavy and heaviest nuclei (from Po to the region of superheavy elements close to Z=114 and N=184 in fusion-evaporation reactions induced by heavy ions has been considered in a systematic way within the framework of the barrier-passing model coupled with the statistical model (SM of de-excitation of a compound nucleus (CN. Excitation functions for fission and evaporation residues (ER measured in very asymmetric combinations can be described rather well. One can scale and fix macroscopic (liquid-drop fission barriers for nuclei involved in the calculation of survivability with SM. In less asymmetric combinations, effects of fusion suppression caused by quasi-fission (QF are starting to appear in the entrance channel of reactions. QF effects could be semi-empirically taken into account using fusion probabilities deduced as the ratio of measured ER cross sections to the ones obtained in the assumption of absence of the fusion suppression in corresponding reactions. SM parameters (fission barriers obtained at the analysis of a very asymmetric combination leading to the production of (nearly the same CN should be used for this evaluation.

Analysis of the accident with the coolant discharge into the plasma vessel of the W7-X fusion experimental facility

Energy Technology Data Exchange (ETDEWEB)

Ušpuras, E.; Kaliatka, A.; Kaliatka, T., E-mail: tadas@mail.lei.lt

2013-06-15

Highlights: • The accident with water ingress into the plasma vessel in Wendelstein nuclear fusion device W7-X was analyzed. • The analysis of the processes in the plasma vessel and ventilation system was performed using thermal-hydraulic RELAP5 Mod3.3 code. • The suitability of pressure increase prevention system was assessed. • All analyses results will be used for the optimization of W7-X design and to ensure safe operation of this nuclear fusion device. -- Abstract: Fusion is the energy production technology, which could potentially solve problems with growing energy demand of population in the future. Starting 2007, Lithuanian Energy Institute (LEI) is a member of European Fusion Development Agreement (EFDA) organization. LEI is cooperating with Max Planck Institute for Plasma Physics (IPP, Germany) in the frames of EFDA project by performing safety analysis of fusion device W7-X. Wendelstein 7-X (W7-X) is an experimental stellarator facility currently being built in Greifswald, Germany, which shall demonstrate that in the future energy could be produced in such type of fusion reactors. In this paper the safety analysis of 40 mm inner diameter coolant pipe rupture in cooling circuit and discharge of steam–water mixture through the leak into plasma vessel during the W7-X no-plasma “baking” operation mode is presented. For the analysis the model of W7-X cooling system (pumps, valves, pipes, hydro-accumulators, and heat exchangers) and plasma vessel was developed by employing system thermal-hydraulic state-of-the-art RELAP5 Mod3.3 code. This paper demonstrated that the developed RELAP5 model enables to analyze the processes in divertor cooling system and plasma vessel. The results of analysis demonstrated that the proposed burst disc, connecting the plasma vessel with venting system, opens and pressure inside plasma vessel does not exceed the limiting 1.1 × 10{sup 5} Pa absolute pressure. Thus, the plasma vessel remains intact after loss

Effects of breakup of weakly bound projectile and neutron transfer on fusion reactions around Coulomb barrier

International Nuclear Information System (INIS)

Lin, C.J.; Zhang, H.Q.; Yang, F.; Ruan, M.; Liu, Z.H.; Wu, Y.W.; Wu, X.K.; Zhou, P.; Zhang, C.L.; Zhang, G.L.; An, G.P.; Jia, H.M.; Xu, X.X.

2007-01-01

The excitation functions of quasielastic and elastic scattering at backward angles have been measured for the systems of 16 O+ 152 Sm, 6,7 Li+ 208 Pb and 32 S+ 90,96 Zr. The barrier distributions are extracted from these measured excitation functions and compared with the corresponding fusion barrier distributions. Except some details, the barrier distributions derived from the data of fusion and quasielastic/elastic scattering are almost the same for the tightly bound reaction systems. For the reaction systems with weakly bound projectile, the barrier distributions extracted from quasielastic scattering are obviously different from the fusion barrier distributions. However, the barrier distributions extracted from the excitation functions of the quasielastic scattering plus breakup are almost the same as the one extracted from the complete fusion data. This result means that barrier distribution not only bears the information of nuclear structures but also contains the knowledge of reaction mechanisms. Our results show that the complete fusion of the weakly bound projectile with heavy target is suppressed at the above barrier energies as compared with the model predictions. In addition, the measured barrier distribution of 32 S+ 96 Zr is broaden and extends to lower energy than in the case of 32 S+ 90 Zr due to the coupling of neutron transfer with positive Q-values, which result in a significant enhancement of fusion cross sections at the subbarrier energies

Multiple electromagnetic excitations of relativistic projectiles

International Nuclear Information System (INIS)

Llope, W.J.; Braun-Munzinger, P.

1992-01-01

Conditions optimum for the first experimental verification of the multiplication electromagnetic excitations of nuclei in relativistic nucleus-nucleus collisions are described. The relative magnitudes of three important physical processes that might interfere with such a measurement are compared to the predicted strengths for the single and multiple electromagnetic excitations for various choices of the projectile mass and beam energy. Strategies are presented for making inferences concerning the presence of multiple excitation strength in experimental data

Overview on Fusion Nuclear Technology Experimental Testing

Czech Academy of Sciences Publication Activity Database

Entler, Slavomír; Kysela, J.

2016-01-01

Roč. 2, č. 2 (2016), č. článku 021018. ISSN 2332-8983 Institutional support: RVO:61389021 Keywords : fusion * corrosion * thermohydraulic * LiPb * HHF * ITER Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

Contribution to the experimental study of excited states of 58,60,62,64Ni

International Nuclear Information System (INIS)

Beuzit, Pierre

1971-01-01

In its experimental part, this research thesis addresses the use of nuclear spectrometry to study electromagnetic properties of excited states of 58,60,62,64 Ni by using coincidence measurements of particles scattered by the nucleus, and of γ lines emitted by the nucleus in reaction. The author also computed energies, wave functions and transition probabilities of levels related to the quasi-particle model according the RPA (random phase approximation) approximation. After a description of the experimental device and a presentation of data reduction methods, the author reports the experimental results. Then, after a recall of theoretical models and calculation approximations, the author discusses the calculated results obtained within the framework of the layer model, and presents those obtained by using the quasi-particle model with the RPA approximation. By using experimental results, a level classification is proposed. The importance of the core configuration and of the proton-neutron interaction is highlighted

Study of the giant dipole resonance built on highly excited states in Sn and Dy nuclei

International Nuclear Information System (INIS)

Stolk, A.

1988-01-01

A study is presented of the giant dipole resonance built on highly excited states. The aim is to get more detailed information on the properties of the GDR and to use it as a tool for the investigation of nuclear structure at high excitation energy. The high energy γ-rays seen from the decay of excited state GDRs in heavy ion fusion reactions reflect the average properties of the states populated by the γ-emission. The measurements at different initial excitation energies of 114 Sn provide information on the nuclear level density near the particle separation energy at an average angular momentum of 10ℎ. The study of shape changes at very high spin in 152-156 Dy nuclei is presented. A theoretical model developed to describe fusion-evaporation reactions is presented. 149 refs.; 63 figs.; 13 tabs

Cold fusion in symmetric 90Zr induced reactions

International Nuclear Information System (INIS)

Keller, J.G.; Schmidt, K.H.; Hessberger, F.P.; Muenzenberg, G.; Reisdorf, W.; Clerc, H.G.; Sahm, C.C.

1985-08-01

Excitation functions for evaporation residues were measured for the reactions 90 Zr+ 89 Y, 90 Zr, 92 Zr, 96 Zr, and 94 Mo. Deexcitation only by γ radiation was found for the compound nuclei 179 Au, 180 Hg, 182 Hg, and 184 Pb. The cross sections for this process were found to be considerably larger than predicted by a statistical-model calculation using standard parameters for the γ-strength function. Fusion probabilities as well as fusion-barrier distributions were deduced from the measured cross sections. There are strong nuclear structure effects in subbarrier fusion. For energies far below the fusion barrier the increase of the fusion probabilities with increasing energy is found to be much steeper than predicted by WKB calculations. As a by-product of this work new α-spectroscopic information could be obtained for neutron deficient isotopes between Ir and Pb. (orig.)

Nuclear fusion experimental study on 16 O + 60 Ni system

International Nuclear Information System (INIS)

Silva, C.P. da.

1990-01-01

Nuclear fusion cross section measurements were performed in the energy range near The Coulomb Barrier (E Lab -> 40-72 MeV), for the system 16 O + 60 Ni, aiming the study of Fusion Process involving heavy ions. (L.C.J.A.)

Can Measured Synergy Excitations Accurately Construct Unmeasured Muscle Excitations?

Science.gov (United States)

Bianco, Nicholas A; Patten, Carolynn; Fregly, Benjamin J

2018-01-01

Accurate prediction of muscle and joint contact forces during human movement could improve treatment planning for disorders such as osteoarthritis, stroke, Parkinson's disease, and cerebral palsy. Recent studies suggest that muscle synergies, a low-dimensional representation of a large set of muscle electromyographic (EMG) signals (henceforth called "muscle excitations"), may reduce the redundancy of muscle excitation solutions predicted by optimization methods. This study explores the feasibility of using muscle synergy information extracted from eight muscle EMG signals (henceforth called "included" muscle excitations) to accurately construct muscle excitations from up to 16 additional EMG signals (henceforth called "excluded" muscle excitations). Using treadmill walking data collected at multiple speeds from two subjects (one healthy, one poststroke), we performed muscle synergy analysis on all possible subsets of eight included muscle excitations and evaluated how well the calculated time-varying synergy excitations could construct the remaining excluded muscle excitations (henceforth called "synergy extrapolation"). We found that some, but not all, eight-muscle subsets yielded synergy excitations that achieved >90% extrapolation variance accounted for (VAF). Using the top 10% of subsets, we developed muscle selection heuristics to identify included muscle combinations whose synergy excitations achieved high extrapolation accuracy. For 3, 4, and 5 synergies, these heuristics yielded extrapolation VAF values approximately 5% lower than corresponding reconstruction VAF values for each associated eight-muscle subset. These results suggest that synergy excitations obtained from experimentally measured muscle excitations can accurately construct unmeasured muscle excitations, which could help limit muscle excitations predicted by muscle force optimizations.

Role of giant resonance excitation in heavy ion collisions

International Nuclear Information System (INIS)

Catara, F.; Chomaz, Ph.

1987-01-01

In this paper we discuss several aspects of heavy ion collisions involving collective vibrational modes. In our approach the relative motion is treated in a semiclassical approximation, while the intrinsic degrees of freedom are described microscopically within the RPA. The differences with respect to macroscopic models are analyzed in the appendix. First we present some results on the inelastic scattering cross section and we show that the structures observed experimentally can be explained in terms of multiple excitation of the Giant Quadrupole Resonance. After we calculate an adiabatic polarization potential describing the coupling to the collective vibrational modes and show that it produces a strong enhancement of the subbarrier fusion cross section. This enhancement is found to be enough to reproduce the experimental data for symmetric systems, while for asymmetric reactions the coupling to other degrees of freedom, like transfer, is needed. Finally we report some preliminary results on a dynamical calculation of the real and imaginary parts of the polarization potential. We show that at high incident energies (E/A > 20MeV) the role of the Giant Quadrupole Resonance becomes dominant

Impurity studies in fusion devices using laser-fluorescence-spectroscopy

International Nuclear Information System (INIS)

Husinsky, W.R.

1980-08-01

Resonance fluorescence excitation of neutral atoms using tunable radiation from dye lasers offers a number of unique advantages for impurity studies in fusion devices. Using this technique, it is possible to perform local, time-resolved measurements of the densities and velocity distributions of metallic impurities in fusion devices without disturbing the plasma. Velocities are measured by monitoring the fluorescence intensity while tuning narrow bandwidth laser radiation through the Doppler - broadened absorbtion spectrum of the transition. The knowledge of the velocity distribution of neutral impurities is particularly useful for the determination of impurity introduction mechanisms. The laser fluorescence technique will be described in terms of its application to metallic impurities in fusion devices and related laboratory experiments. Particular attention will be given to recent results from the ISX-B tokamak using pulsed dye lasers where detection sensitivities for neutral Fe of 10 6 atoms/cm 3 with a velocity resolution of 600 m/sec (0.1 eV) have been achieved. Techniques for exciting plasma particles (H,D) will also be discussed

Conceptual design study of fusion experimental reactor (FY86 FER)

International Nuclear Information System (INIS)

Saito, Ryusei; Kashihara, Shin-ichiro; Itoh, Shin-ichi

1987-08-01

This report describes the results of conceptual design study on plant systems for the Fusion Experimental Reactor (FY86 FER). Design studies for FER plant systems have been continued from FY85, especially for design modifications made in accordance with revisions of plasma scaling parameters and system improvements. This report describes 1) system construction, 2) site and reactor building plan, 3) repaire and maintenance system, 4) tritium circulation system, 5) heating, ventilation and air conditioning system, 6) tritium clean-up system, 7) cooling and baking system, 8) waste treatment and storage system, 9) control system, 10) electric power system, 11) site factory plan, all of which are a part of FY86 design work. The plant systems described in this report generally have been based on the FY86 FER (ACS Reactor) which is an one of the six candidates for FER. (author)

Simulation for evaluation of the multi-ion-irradiation Laboratory of TechnoFusion facility and its relevance for fusion applications

International Nuclear Information System (INIS)

Jimenez-Rey, D.; Mota, F.; Vila, R.; Ibarra, A.; Ortiz, Christophe J.; Martinez-Albertos, J.L.; Roman, R.; Gonzalez, M.; Garcia-Cortes, I.; Perlado, J.M.

2011-01-01

Thermonuclear fusion requires the development of several research facilities, in addition to ITER, needed to advance the technologies for future fusion reactors. TechnoFusion will focus in some of the priority areas identified by international fusion programmes. Specifically, the TechnoFusion Area of Irradiation of Materials aims at surrogating experimentally the effects of neutron irradiation on materials using a combination of ion beams. This paper justifies this approach using computer simulations to validate the multi-ion-irradiation Laboratory. The planned irradiation facility will investigate the effects of high energetic radiations on reactor-relevant materials. In a second stage, it will also be used to analyze the performance of such materials and evaluate newly designed materials. The multi-ion-irradiation Laboratory, both triple irradiation and high-energy proton irradiation, can provide valid experimental techniques to reproduce the effect of neutron damage in fusion environment.

On experimental determination of characteristics of nuclear fusion reactions from mu-molecular resonance states

International Nuclear Information System (INIS)

Bystritskij, V.M.; Pen'kov, F.M.

1997-01-01

Charge-nonsymmetrical deuterium-helium muon complexes (dμHe) are studied. A method is proposed for experimentally determining the rates of nuclear fusion reactions in dμHe molecules in the J=1 and J=0 states (J is the orbital moment of the system) and the partial rates for radiative decay of these complexes in these states. Experiments are supposed to be carried out at meson factories with gaseous and cryogenic targets filled with a mixture of deuterium and helium

Basic experiments during loss of vacuum event (LOVE) in fusion experimental reactor

International Nuclear Information System (INIS)

Ogawa, Masuro; Kunugi, Tomoaki; Seki, Yasushi

1993-01-01

If a loss of vacuum event (LOVE) occurs due to damage of the vacuum vessel of a nuclear fusion experimental reactor, some chemical reactions such as a graphic oxidation and a buoyancy-driven exchange flow take place after equalization of the gas pressure between the inside and outside of the vacuum vessel. The graphite oxidation would generate inflammable carbon monoxide and release tritium retained in the graphite. The exchange flow through the breaches may transport the carbon monoxide and tritium out of the vacuum vessel. To add confidence to the safety evaluations and analyses, it is important to grasp the basic phenomena such as the exchange flow and the graphite oxidation. Experiments of the exchange flow and the graphite oxidation were carried out to obtain the exchange flow rate and the rate constant for the carbon monoxide combustion, respectively. These experimental results were compared with existing correlations. The authors plan a scaled-model test and a full-scale model test for the LOVE

Experimental measurement of the 12C+16O fusion cross sections at astrophysical energies

Science.gov (United States)

Fang, X.; Tan, W. P.; Beard, M.; deBoer, R. J.; Gilardy, G.; Jung, H.; Liu, Q.; Lyons, S.; Robertson, D.; Setoodehnia, K.; Seymour, C.; Stech, E.; Vande Kolk, B.; Wiescher, M.; de Souza, R.; Hudan, S.; Singh, V.; Tang, X. D.; Uberseder, E.

2018-05-01

The total cross sections of the 12C+16O fusion have been experimentally determined at low energies to investigate the role of this reaction during late stellar evolution burning phases. A high-intensity oxygen beam was produced by the 5MV pelletron accelerator at the University of Notre Dame impinging on a thick ultra-pure graphite target. Protons and γ-rays were measured simultaneously in the center-of-mass energy range from 3.64 to 5.01 MeV, using strip silicon and HPGe detectors. Statistical model calculations were employed to interpret the experimental results. A new broad resonance-like structure is observed for the 12C+16O reaction, and a decreasing trend of its S-factor towards low energies is found.

Recent results on fusion and direct reactions with weakly bound stable nuclei

International Nuclear Information System (INIS)

Shrivastava, A.

2011-01-01

Recent measurements of fusion and direct reactions in case of weakly bound stable nuclei at extreme sub-barrier energies using a sensitive off beam technique are presented. First section deals with deep sub-barrier fusion cross-section measurement for 67 Li + 198 Pt followed by the study of fragment capture reaction of 7 Li + 198 Pt. Deviation in the slope of the fusion excitation function, as observed in case of medium heavy systems, is absent in the present asymmetric systems at these low energies. This study shows the absence of fusion hindrance, suggesting modifications in models that explain deep sub-barrier fusion data to incorporate weakly bound asymmetric systems

Remote maintenance design for Fusion Experimental Reactor (FER)

International Nuclear Information System (INIS)

Tachikawa, K.; Iida, H.; Nishio, S.; Tone, T.; Aota, T.; Iwamoto, T.; Niikura, S.; Nishizawa, H.

1984-01-01

Design of Fusion Experimental Reactor, FER, has been conducted by Japan Atomic Energy Research Institute (JAERI) since 1981. Two typical reactors can be classified in general from the viewpoints of remote maintenance among four design concepts of FER. In the case of the type 1 FER, the torus module consists of shield structure and blanket, and the connective joints between toruses provided at the outer region of the reactor. As for the type 2 FER, the shield structure is joined with the vacuum cryostat, and only the blanket module is allowed to move, but connection between toruses are located in the inner region of the reactor. Comparing type 1 with type 2 FER, this paper describes on the remote maintenance of FER including reactor configurations, work procedures, remote systems/equipments, repairing facility and future R and D problems. Reviewing design studies and investigation for the existing robotics technologies, R and D for FER remote maintenance technology should be performed under the reasonable long-term program. The main items of remote technology required to start urgently are multi-purpose manipulator system with performance of dextrousity, tele-viewing system which reduces operator fatigue and remote tests for commercially available components

Resonantly enhanced production of excited fragments of gaseous molecules following core-level excitation

International Nuclear Information System (INIS)

Chen, J.M.; Lu, K.T.; Lee, J.M.; Ho, S.C.; Chang, H.W.; Lee, Y.Y.

2005-01-01

State-selective dissociation dynamics for the excited fragments of gaseous Si(CH 3 ) 2 Cl 2 following Cl 2p and Si 2p core-level excitations have been investigated by resonant photoemission spectroscopy and dispersed UV/optical fluorescence spectroscopy. The main features in the gaseous Si(CH 3 ) 2 Cl 2 fluorescence spectrum are identified as the emission from excited Si*, Si + *, CH* and H*. The core-to-Rydberg excitations at both Si 2p and Cl 2p edges lead to a noteworthy production of not only the excited atomic fragments, neutral and ionic (Si*, Si + *) but also the excited diatomic fragments (CH*). In particular, the excited neutral atomic fragments Si* are significantly reinforced. The experimental results provide deeper insight into the state-selective dissociation dynamics for the excited fragments of molecules via core-level excitation

A traveling wave direct energy converter for a D-3He fusion reactor

International Nuclear Information System (INIS)

Sato, K.; Katayama, H.; Miyawaki, F.; Tajima, T.

1994-01-01

A concept of a traveling wave direct energy converter (TWDEC) is developed for 14.7-MeV fusion protons based on the principle of a backward wave oscillator. Separation of fusion protons from thermal ions is accomplished by using ExB ion drift. Energy conversion rate up to 0.87 is attained by applying three-stage modulation of the proton beam. A one-dimensional particle-circuit code is developed to examine self-excitation of the traveling wave and its stability under loading. Electrostatic wave with a fixed frequency is excited spontaneously, and stability of the wave is ensured under loading. (author)

A new analysis technique to measure fusion excitation functions with large beam energy dispersions

Science.gov (United States)

Figuera, P.; Di Pietro, A.; Fisichella, M.; Lattuada, M.; Shotter, A. C.; Ruiz, C.; Zadro, M.

2018-01-01

Peculiar nuclear structures of two colliding nuclei such has clustering, neutron halo/skin or very low breakup thresholds can affect the reaction dynamics below the Coulomb barrier and this may also have astrophysical consequences. In order to have a better understanding of this topic, in the last decade, several experiments were performed. A typical experimental challenge of such studies is the need to measure excitation functions below the Coulomb barrier, having a strong energy dependence, with rather large beam energy dispersions inside the target. This may easily lead to ambiguities in associating the measured cross section with a proper beam energy. In this paper a discussion on this topic is reported and a new technique to deal with the above problem will be proposed.

Experimental Study on Bioluminescence Tomography with Multimodality Fusion

Directory of Open Access Journals (Sweden)

Yujie Lv

2007-01-01

Full Text Available To verify the influence of a priori information on the nonuniqueness problem of bioluminescence tomography (BLT, the multimodality imaging fusion based BLT experiment is performed by multiview noncontact detection mode, which incorporates the anatomical information obtained by the microCT scanner and the background optical properties based on diffuse reflectance measurements. In the reconstruction procedure, the utilization of adaptive finite element methods (FEMs and a priori permissible source region refines the reconstructed results and improves numerical robustness and efficiency. The comparison between the absence and employment of a priori information shows that multimodality imaging fusion is essential to quantitative BLT reconstruction.

Electron-impact excitation of the potassium atom

International Nuclear Information System (INIS)

Phelps, J.O.; Solomon, J.E.; Korff, D.F.; Lin, C.C.; Lee, E.T.P.

1979-01-01

Absolute optical electron-impact excitation functions for 24 transitions of the sharp, principal, diffuse, and fundamental spectral series of potassium have been measured. The determination of the density of the potassium vapor in the collision chamber was made by measuring the degree of transmission, by the vapor, of potassium resonance radiation generated externally in a fluorescence cell. Direct excitation functions were determined for 14 states (5S, 6S, 7S, 8S, 4P, 5P, 6P, 7P, 3D, 5D, 6D, 5F, 6F, and 7F) with the aid of known radiative-transition probabilities. Theoretical calculations of these same 14 excitation functions, as well as 4D and 4F, were carried out by means of the Born approximation. The 4P, 5P, 5S, 3D, and 4D direct excitation functions at intermediate energies (10--25 eV) were also calculated by the method of multistate close coupling, neglecting projectile--target-electron exchange. The high-energy (above 100 eV) Born-approximation cross sections agree with the experimental results for 4P and for all S states, but are lower than experimental results, by 30--40%, for the D and F states. At intermediate energies the close-coupling excitation calculations agree well with the experimental excitation functions for 4P and 5P, but are significantly higher than experimental values for 5S and 3D. The discrepancies between the experimental and theoretical results are probably due to a combination of systematic experimental errors, errors in the available transition-probability values, and errors in the theoretical excitation functions introduced by the use of approximate excited-state wave functions (Hartree-Fock-Slater), by the neglect of projectile--target-electron exchange. The polarization of the 4P-4S and 3D-4P radiation produced by electron impact was measured, and the results were used to determine the direct excitation functions of the separate magnetic sublevels of the 4P state

Experimental and numerical response of rigid slender blocks with geometrical defects under seismic excitation

Directory of Open Access Journals (Sweden)

Mathey Charlie

2015-01-01

Full Text Available The present work investigates on the influence of small geometrical defects on the behavior of slender rigid blocks. A comprehensive experimental campaign was carried out on one of the shake tables of CEA/Saclay in France. The tested model was a massive steel block with standard manufacturing quality. Release, free oscillations tests as well as shake table tests revealed a non-negligible out-of-plane motion even in the case of apparently plane initial conditions or excitations. This motion exhibits a highly reproducible part for a short duration that was used to calibrate a numerical geometrically asymmetrical model. The stability of this model when subjected to 2 000 artificial seismic horizontal bidirectional signals was compared to the stability of a symmetrical one. This study showed that the geometrical imperfections slightly increase the rocking and overturning probabilities under bidirectional seismic excitations in a narrow range of peak ground acceleration.

New trends in fusion research

CERN Multimedia

CERN. Geneva

2004-01-01

The efforts of the international fusion community aim at demonstrating the scientific feasibility of thermonuclear fusion energy power plants. Understanding the behavior of burning plasmas, i.e. plasmas with strong self-heating, represents a primary scientific challenge for fusion research and a new science frontier. Although integrated studies will only be possible, in new, dedicated experimental facilities, such as the International Tokamak Experimental Reactor (ITER), present devices can address specific issues in regimes relevant to burning plasmas. Among these are an improvement of plasma performance via a reduction of the energy and particle transport, an optimization of the path to ignition or to sustained burn using additional heating and a control of plasma-wall interaction and energy and particle exhaust. These lectures address recent advances in plasma science and technology that are relevant to the development of fusion energy. Mention will be made of the inertial confinement line of research, but...

Investigation of excitation functions using new evaluated empirical and semi-empirical systematic for 14-15 MeV (n, t) reaction cross sections

International Nuclear Information System (INIS)

Tel, E.; Aydin, E. G.; Aydin, A.; Kaplan, A.

2007-01-01

The hybrid reactor is a combination of the fusion and fission processes. In the fusion-fission hybrid reactor, tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. Working out the systematics of (n,t) reaction cross sections is of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at energies up to 20 MeV. In this study, we have investigated the asymmetry term effect for the (n,t) reaction cross sections at 14-15 neutron incident energy. It has been discussed the odd even effect and the pairing effect considering binding energy systematic of the nuclear shell model for the new experimental data and new cross section formulas (n,t) reactions developed by Tel et al. We have determined a different parameter groups by the classification of nuclei into even-even, even-odd and odd-even for (n,t) reactions cross sections. The obtained empirical formulas by fitting two parameter for (n,t) reactions were given. All calculated results have been compared with the experimental data. By using the new cross sections formulas (n,t) reactions the obtained results have been discussed and compared with the available experimental data

Measurement of the X and gamma radiation after muon-catalyzed pd-, dd-, and dt-fusion

International Nuclear Information System (INIS)

Bossy, H.

1987-01-01

The muonic X radiation emitted after muon-catalyzed fusion of two hydrogen nuclei has been measured for the fusion reactions of pd, dd, and dt (p=proton, d=deuteron, t=triton). The quantum yields (per fusion) of the μHe(2-1) transition were evaluated to be 3.2(4)% (pd fusion), 1.6(2)% (dd fusion), and 0.21(5)% (dt fusion, preliminary value). The intensity ratios of the transitions μHe(3-1)/μHe(2-1) were found to be 0.052(5) (pd fusion) and 0.13(2) (dd fusion). The investigation of the gamma radiation intensities for pd fusion yielded excitement probabilities of the μHe atom. (orig.) [de

Experimental stand-alone self-excited induction generator driven by a diesel motor

Directory of Open Access Journals (Sweden)

Mhamdi Taoufik

2017-12-01

Full Text Available This paper presents an experimental work to design and size a diesel generator (DG. The basic system is equipped with a 1.5 kW self-excited induction generator (SEIG, a diesel motor (DM, a static voltage compensator (SVC and controllers. A proportional integral controller is used to meet the requirement of the SEIG frequency regulation. A controlled voltage source is performed by using an SVC with a fuzzy controller, which adjusts voltage by varying the amount of the injected reactive power. An experimental set-up is used to identify the SEIG parameters and select the convenient bank of capacitors that minimize the SEIG starting up time and fix the convenient margin of voltage. The system has been tested by simulation using models implemented by Matlab/Simulink software. The simulation results confirm the efficiency of the proposed strategy of voltage regulation. Keywords: Diesel motor, SEIG, SVC, Voltage regulation, Frequency regulation

Laser fusion

International Nuclear Information System (INIS)

Ashby, D.E.T.F.

1976-01-01

A short survey is given on laser fusion its basic concepts and problems and the present theoretical and experimental methods. The future research program of the USA in this field is outlined. (WBU) [de

Atomic and plasma-material interaction data for fusion. V. 2

International Nuclear Information System (INIS)

1992-01-01

This issues of the Atomic and Plasma-Material Interaction Data for Fusion contains 9 papers on atomic and molecular processes in the edge region of magnetically confined fusion plasmas, including spectroscopic data for fusion edge plasmas; electron collision processes with plasma edge neutrals; electron-ion collisions in the plasma edge; cross-section data for collisions of electrons with hydrocarbon molecules; dissociative and energy transfer reactions involving vibrationally excited hydrogen or deuterium molecules; an assessment of ion-atom collision data for magnetic fusion plasma edge modeling; an extended scaling of cross sections for the ionization of atomic and molecular hydrogen as well as helium by multiply-charged ions; ion-molecule collision processes relevant to fusion edge plasmas; and radiative losses and electron cooling rates for carbon and oxygen plasma impurities. Refs, figs and tabs

Stochastic semi-classical description of sub-barrier fusion reactions

Directory of Open Access Journals (Sweden)

Ayik Sakir

2011-10-01

Full Text Available A semi-classical method that incorporates the quantum effects of the low-lying vibrational modes is applied to fusion reactions. The quantum effect is simulated by stochastic sampling of initial zero-point fluctuations of the surface modes. In this model, dissipation of the relative energy into non-collective excitations of nuclei can be included straightforwardly. The inclusion of dissipation is shown to increase the agreement with the fusion cross section data of Ni isotopes.

Fusion energy science: Clean, safe, and abundant energy through innovative science and technology

International Nuclear Information System (INIS)

2001-01-01

Fusion energy science combines the study of the behavior of plasmas--the state of matter that forms 99% of the visible universe--with a vision of using fusion--the energy source of the stars--to create an affordable, plentiful, and environmentally benign energy source for humankind. The dual nature of fusion energy science provides an unfolding panorama of exciting intellectual challenge and a promise of an attractive energy source for generations to come. The goal of this report is a comprehensive understanding of plasma behavior leading to an affordable and attractive fusion energy source

Fusion Simulation Program

International Nuclear Information System (INIS)

Greenwald, Martin

2011-01-01

Many others in the fusion energy and advanced scientific computing communities participated in the development of this plan. The core planning team is grateful for their important contributions. This summary is meant as a quick overview the Fusion Simulation Program's (FSP's) purpose and intentions. There are several additional documents referenced within this one and all are supplemental or flow down from this Program Plan. The overall science goal of the DOE Office of Fusion Energy Sciences (FES) Fusion Simulation Program (FSP) is to develop predictive simulation capability for magnetically confined fusion plasmas at an unprecedented level of integration and fidelity. This will directly support and enable effective U.S. participation in International Thermonuclear Experimental Reactor (ITER) research and the overall mission of delivering practical fusion energy. The FSP will address a rich set of scientific issues together with experimental programs, producing validated integrated physics results. This is very well aligned with the mission of the ITER Organization to coordinate with its members the integrated modeling and control of fusion plasmas, including benchmarking and validation activities. (1). Initial FSP research will focus on two critical Integrated Science Application (ISA) areas: ISA1, the plasma edge; and ISA2, whole device modeling (WDM) including disruption avoidance. The first of these problems involves the narrow plasma boundary layer and its complex interactions with the plasma core and the surrounding material wall. The second requires development of a computationally tractable, but comprehensive model that describes all equilibrium and dynamic processes at a sufficient level of detail to provide useful prediction of the temporal evolution of fusion plasma experiments. The initial driver for the whole device model will be prediction and avoidance of discharge-terminating disruptions, especially at high performance, which are a critical

Cold versus hot fusion deuterium branching ratios

International Nuclear Information System (INIS)

Fox, H.; Bass, R.

1995-01-01

A major source of misunderstanding of the nature of cold nuclear fusion has been the expectation that the deuterium branching ratios occurring within a palladium lattice would be consistent with the gas-plasma branching ratios. This misunderstanding has led to the concept of the dead graduate student, the 1989's feverish but fruitless search for neutron emissions from cold fusion reactors, and the follow-on condemnation of the new science of cold fusion. The experimental facts are that in a properly loaded palladium lattice, the deuterium fusion produces neutrons at little above background, a greatly less-than-expected production of tritium (the tritium desert), and substantially more helium-4 than is observed in hot plasma physics. The experimental evidence is now compelling (800 reports of success from 30 countries) that cold nuclear fusion is a reality, that the branching ratios are unexpected, and that a new science is struggling to be recognized. Commercialization of some types of cold fusion devices has already begun

An experimental investigation of stimulated Brillouin scattering in laser-produced plasmas relevant to inertial confinement fusion

International Nuclear Information System (INIS)

Bradley, K.S.

1993-01-01

Despite the apparent simplicity of controlled fusion, there are many phenomena which have prevented its achievement. One phenomenon is laser-plasma instabilities. An investigation of one such instability, stimulated Brillouin scattering (SBS), is reported here. SBS is a parametric process whereby an electromagnetic wave (the parent wave) decays into another electromagnetic wave and an ion acoustic wave (the daughter waves). SBS impedes controlled fusion since it can scatter much or all of the incident laser light, resulting in poor drive symmetry and inefficient laser-plasma coupling. It is widely believed that SBS becomes convectively unstable--that is, it grows as it traverses the plasma. Though it has yet to be definitively tested, convective theory is often invoked to explain experimental observations, even when one or more of the theory's assumptions are violated. In contrast, the experiments reported here not only obeyed the assumptions of the theory, but were also conducted in plasmas with peak densities well below quarter-critical density. This prevented other competing or coexisting phenomena from occurring, thereby providing clearly interpretable results. These are the first SBS experiments that were designed to be both a clear test of linear convective theory and pertinent to controlled fusion research. A crucial part of this series of experiments was the development of a new instrument, the Multiple Angle Time Resolving Spectrometer (MATRS). MATRS has the unique capability of both spectrally and temporally resolving absolute levels of scattered light at many angles simultaneously, and is the first of its kind used in laser-plasma experiments. A detailed comparison of the theoretical predictions and the experimental observations is made

Influence of INCONEL 625 composition on the activation characteristics of the vacuum vessel of experimental fusion tokamaks

International Nuclear Information System (INIS)

Cambi, G.; Cepraga, D.G.; Boeriu, S.; Maganzani, I.

1995-01-01

The radioactive inventory, the decay heat and the contact dose rate of permanent components such as the vacuum vessel of two experimental fusion tokamaks, the compact IGNITOR-ULT and the ITER-EDA fusion machines, are evaluated by using the ENEA-Bologna integrated methodology. The vacuum vessel material considered is the INCONEL 625. The neutron flux is calculated using the VITAMIN-C 171-group library, based on EFF-2 data and the 1-D transport code XSDRNPM in the S 8 -P 3 approximation. The ANITA-2 code, using updated cross sections and decay data libraries based on EAF-3 and IRDF90 evaluation files is used for activation calculations. The fusion neutron source has been normalised to a neutron first wall load of 2 MW/m 2 and 1 MW/m 2 for IGNITOR-ULT and ITER, respectively. The material irradiation have been described by multistep time histories, resulting in the designed total fluence. Variations in the composition of INCONEL 625 have been assessed and their impact on the activation characteristics are discussed, also from the point of view of waste disposal. (orig.)

The controlled thermonuclear fusion

International Nuclear Information System (INIS)

Barre, Bertrand

2014-01-01

After some generalities on particle physics, and on fusion and fission reactions, the author outlines that the fission reaction is easier to obtain than the fusion reaction, evokes the fusion which takes place in stars, and outlines the difficulty to manage and control this reaction: one of its application is the H bomb. The challenge is therefore to find a way to control this reaction and make it a steady and continuous source of energy. The author then presents the most promising way: the magnetic confinement fusion. He evokes its main issues, the already performed experiments (tokamak), and gives a larger presentation of the ITER project. Then, he evokes another way, the inertial confinement fusion, and the two main experimental installations (National Ignition Facility in Livermore, and the Laser Megajoule in Bordeaux). Finally, he gives a list of benefits and drawbacks of an industrial nuclear fusion

Electronic-excitation energy transfer in heterogeneous dye solutions under laser excitation

International Nuclear Information System (INIS)

Levshin, L.V.; Mukushev, B.T.; Saletskii, A.M.

1995-01-01

An experimental study has been made of electronic-excitation energy transfer (EEET) among dye molecules of different types for different exciting-fight wavelengths and temperatures. Upon selective laser excitation of the donor, the inhomogeneous broadening of molecular levels increases the probability of EEET from the donor to acceptor molecules. The efficiency of this process is directly proportional to the acceptor molecule concentration and is temperature dependent. The EEET is accompanied by the spectral migration of energy among donor molecules, which reduces the fluorescence quantum efficiency of the donor. Increasing the frequency of the exciting light decreases in the donor fluorescence quantum efficiency. An increase in the acceptor molecule concentration results in a decrease of the spectral migration of excitation in the donor molecule system. 5 refs., 5 figs

Clustering effects in fusion evaporation reactions with light even-even N = Z nuclei. The {sup 24}Mg and {sup 28}Si cases

Energy Technology Data Exchange (ETDEWEB)

Morelli, L., E-mail: luca.morelli@bo.infn.it; D’Agostino, M.; Bruno, M. [Dipartimento di Fisica e Astronomia dell’Università and INFN, Bologna (Italy); Baiocco, G. [Dipartimento di Fisica dell’Università and INFN, Pavia (Italy); Gulminelli, F. [CNRS, LPC, Caen, France and ENSICAEN, Caen (France); Cinausero, M.; Gramegna, F.; Marchi, T. [INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova) (Italy); Degerlier, M. [University of Nevsehir, Physics Department, Nevsehir (Turkey); Fabris, D. [INFN, Sezione di Padova, Padova (Italy); Barlini, S.; Bini, M.; Casini, G.; Gelli, N.; Olmi, A.; Pasquali, G.; Piantelli, S. [Dipartimento di Fisica e Astronomia dell’Università and INFN, Firenze (Italy)

2015-10-15

In the recent years, cluster structures have been evidenced in many ground and excited states of light nuclei [1, 2]. Within the currently ongoing experimental campaign by the NUCL-EX collaboration we have measured the {sup 12}C+{sup 12}C and {sup 14}N+{sup 10}B reactions at 95 MeV and 80 MeV respectively, and compared experimental data corresponding to complete fusion of target and projectile into an excited {sup 24}Mg nucleus to the results of a pure statistical model[3, 4]. We found clear deviations from the statstical model in the decay pattern: emission channels involving multiple α particles are more probable than expected from a purely statistical behavior. To continue the investigation on light systems, we have recentely measured the {sup 16}O+{sup 12}C reaction at three different beam energies, namely E{sub beam} = 90, 110 and 130 MeV.

Fusion, magnetic confinement

International Nuclear Information System (INIS)

Berk, H.L.

1992-01-01

An overview is presented of the principles of magnetic confinement of plasmas for the purpose of achieving controlled fusion conditions. Sec. 1 discusses the different nuclear fusion reactions which can be exploited in prospective fusion reactors and explains why special technologies need to be developed for the supply of tritium or 3 He, the probable fuels. In Sec. 2 the Lawson condition, a criterion that is a measure of the quality of confinement relative to achieving fusion conditions, is explained. In Sec. 3 fluid equations are used to describe plasma confinement. Specific confinement configurations are considered. In Sec. 4 the orbits of particle sin magneti and electric fields are discussed. In Sec. 5 stability considerations are discussed. It is noted that confinement systems usually need to satisfy stability constraints imposed by ideal magnetohydrodynamic (MHD) theory. The paper culminates with a summary of experimental progress in magnetic confinement. Present experiments in tokamaks have reached the point that the conditions necessary to achieve fusion are being satisfied

Opportunities in the Fusion Energy Sciences Program. Appendix C: Topical Areas Characterization

Energy Technology Data Exchange (ETDEWEB)

None

1999-06-30

Recent years have brought dramatic advances in the scientific understanding of fusion plasmas and in the generation of fusion power in the laboratory. Today, there is little doubt that fusion energy production is feasible. The challenge is to make fusion energy practical. As a result of the advances of the last few years, there are now exciting opportunities to optimize fusion systems so that an attractive new energy source will be available when it may be needed in the middle of the next century. The risk of conflicts arising from energy shortages and supply cutoffs, as well as the risk of severe environmental impacts from existing methods of energy production, are among the reasons to pursue these opportunities.

Near-barrier heavy-ion fusion (panel discussion)

International Nuclear Information System (INIS)

Vandenbosch, R.

1991-01-01

We are approaching a semi-quantitative understanding of the role of the coupling of shape and transfer degrees of freedom in the enhancement of near and sub-barrier fusion cross sections, although there remains some debate about the relative importance of the different degrees of freedom. The information content in fusion excitation functions is limited and it is therefore important to obtain additional information such as higher moments of the partial wave distribution. The present status of information obtained with difference probes will be critically discussed. Among the open problems in sub-barrier fusion is the importance of a neck degree of freedom and a concomitant departure of the inertial mass from the reduced mass. A coupled channels description in terms of the asymptotic exit channels may only converge slowly. (author)

Experimental validation of decay heat calculation codes and associated nuclear data libraries for fusion energy

International Nuclear Information System (INIS)

Maekawa, Fujio; Wada, Masayuki; Ikeda, Yujiro

2001-01-01

Validity of decay heat calculations for safety designs of fusion reactors was investigated by using decay heat experimental data on thirty-two fusion reactor relevant materials obtained at the 14-MeV neutron source facility of FNS in JAERI. Calculation codes developed in Japan, ACT4 and CINAC version 4, and nuclear data bases such as JENDL/Act-96, FENDL/A-2.0 and Lib90 were used for the calculation. Although several corrections in algorithms for both the calculation codes were needed, it was shown by comparing calculated results with the experimental data that most of activation cross sections and decay data were adequate. In cases of type 316 stainless steel and copper which were important for ITER, prediction accuracy of decay heat within ±10% was confirmed. However, it was pointed out that there were some problems in parts of data such as improper activation cross sections, e,g., the 92 Mo(n, 2n) 91g Mo reaction in FENDL, and lack of activation cross section data, e.g., the 138 Ba(n, 2n) 137m Ba reaction in JENDL. Modifications of cross section data were recommended for 19 reactions in JENDL and FENDL. It was also pointed out that X-ray and conversion electron energies should be included in decay data. (author)

Experimental validation of decay heat calculation codes and associated nuclear data libraries for fusion energy

Energy Technology Data Exchange (ETDEWEB)

Maekawa, Fujio; Wada, Masayuki; Ikeda, Yujiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2001-01-01

Validity of decay heat calculations for safety designs of fusion reactors was investigated by using decay heat experimental data on thirty-two fusion reactor relevant materials obtained at the 14-MeV neutron source facility of FNS in JAERI. Calculation codes developed in Japan, ACT4 and CINAC version 4, and nuclear data bases such as JENDL/Act-96, FENDL/A-2.0 and Lib90 were used for the calculation. Although several corrections in algorithms for both the calculation codes were needed, it was shown by comparing calculated results with the experimental data that most of activation cross sections and decay data were adequate. In cases of type 316 stainless steel and copper which were important for ITER, prediction accuracy of decay heat within {+-}10% was confirmed. However, it was pointed out that there were some problems in parts of data such as improper activation cross sections, e,g., the {sup 92}Mo(n, 2n){sup 91g}Mo reaction in FENDL, and lack of activation cross section data, e.g., the {sup 138}Ba(n, 2n){sup 137m}Ba reaction in JENDL. Modifications of cross section data were recommended for 19 reactions in JENDL and FENDL. It was also pointed out that X-ray and conversion electron energies should be included in decay data. (author)

Experimental investigation of snap-through motion of in-plane MEMS shallow arches under electrostatic excitation

KAUST Repository

Ramini, Abdallah

2015-12-11

We present an experimental investigation for the nonlinear dynamic behaviors of clamped–clamped in-plane MEMS shallow arches when excited by harmonic electrostatic forces. Frequency sweeps are conducted to study the dynamic behaviors in the neighborhoods of the first and third resonance frequencies as well as the super-harmonic resonances. Experimental results show local softening behavior of small oscillations around the first resonance frequency and hardening behavior at the third resonance frequency for small dc and ac loads. Interesting dynamic snap-through cross-well motions are observed experimentally at high voltages for the first time in the micro-scale world. In addition to the dynamic snap-through motion, the MEMS arch exhibits large oscillations of a continuous band of snap-through motion between the super-harmonic resonance regime and the first primary resonance regime. This continuous band is unprecedented experimentally in the micro/macro world, and is promising for a variety of sensing, actuation and communications applications.

Experimental investigation of snap-through motion of in-plane MEMS shallow arches under electrostatic excitation

KAUST Repository

Ramini, Abdallah; Bellaredj, Mohammed L F; Al Hafiz, Md Abdullah; Younis, Mohammad I.

2015-01-01

We present an experimental investigation for the nonlinear dynamic behaviors of clamped–clamped in-plane MEMS shallow arches when excited by harmonic electrostatic forces. Frequency sweeps are conducted to study the dynamic behaviors in the neighborhoods of the first and third resonance frequencies as well as the super-harmonic resonances. Experimental results show local softening behavior of small oscillations around the first resonance frequency and hardening behavior at the third resonance frequency for small dc and ac loads. Interesting dynamic snap-through cross-well motions are observed experimentally at high voltages for the first time in the micro-scale world. In addition to the dynamic snap-through motion, the MEMS arch exhibits large oscillations of a continuous band of snap-through motion between the super-harmonic resonance regime and the first primary resonance regime. This continuous band is unprecedented experimentally in the micro/macro world, and is promising for a variety of sensing, actuation and communications applications.

Membrane Fusion Involved in Neurotransmission: Glimpse from Electron Microscope and Molecular Simulation

Directory of Open Access Journals (Sweden)

Zhiwei Yang

2017-06-01

Full Text Available Membrane fusion is one of the most fundamental physiological processes in eukaryotes for triggering the fusion of lipid and content, as well as the neurotransmission. However, the architecture features of neurotransmitter release machinery and interdependent mechanism of synaptic membrane fusion have not been extensively studied. This review article expounds the neuronal membrane fusion processes, discusses the fundamental steps in all fusion reactions (membrane aggregation, membrane association, lipid rearrangement and lipid and content mixing and the probable mechanism coupling to the delivery of neurotransmitters. Subsequently, this work summarizes the research on the fusion process in synaptic transmission, using electron microscopy (EM and molecular simulation approaches. Finally, we propose the future outlook for more exciting applications of membrane fusion involved in synaptic transmission, with the aid of stochastic optical reconstruction microscopy (STORM, cryo-EM (cryo-EM, and molecular simulations.

Membrane Fusion Involved in Neurotransmission: Glimpse from Electron Microscope and Molecular Simulation

Science.gov (United States)

Yang, Zhiwei; Gou, Lu; Chen, Shuyu; Li, Na; Zhang, Shengli; Zhang, Lei

2017-01-01

Membrane fusion is one of the most fundamental physiological processes in eukaryotes for triggering the fusion of lipid and content, as well as the neurotransmission. However, the architecture features of neurotransmitter release machinery and interdependent mechanism of synaptic membrane fusion have not been extensively studied. This review article expounds the neuronal membrane fusion processes, discusses the fundamental steps in all fusion reactions (membrane aggregation, membrane association, lipid rearrangement and lipid and content mixing) and the probable mechanism coupling to the delivery of neurotransmitters. Subsequently, this work summarizes the research on the fusion process in synaptic transmission, using electron microscopy (EM) and molecular simulation approaches. Finally, we propose the future outlook for more exciting applications of membrane fusion involved in synaptic transmission, with the aid of stochastic optical reconstruction microscopy (STORM), cryo-EM (cryo-EM), and molecular simulations. PMID:28638320

Interaction of heavy ions beams with hot and dense plasmas. Application to inertial fusion

International Nuclear Information System (INIS)

Maynard, Gilles

1987-01-01

The subject of this work is the variation with time, on one of the energy and charge state of an heavy ion beam which through a plasma, and on another side, of a target used in ion inertial confinement fusion. We take in account projectile excitation, and higher order corrections to the Born stopping power formula are calculated. Comparison with experimental results in gas and solid are good. In hot plasma case, non-equilibrium charge states are described. We present an hydrodynamic simulation code of one dimension and three temperatures. We show that the shortening of the heavy ions beams with temperature reinforces the radiative transfer importance. (author) [fr

Fusion safety regulations in the United States: Progress and trends

International Nuclear Information System (INIS)

DeLooper, J.

1994-01-01

This paper explores the issue of regulations as they apply to current and future fusion experimental machines. It addresses fusion regulatory issues, current regulations used for fusion, the Tokamak Fusion Test Reactor experience with regulations, and future regulations to achieve fusion's safety and environmental potential

Conceptual design study of fusion experimental reactor (FY86FER)

International Nuclear Information System (INIS)

Nakashima, Kunihiko; Ishigaki, Yukio; Ozaki, Akira; Yamane, Minoru.

1987-09-01

This report describes the results of the capacity estimation for the electrical power system on the typical two candidates for the FER (Fusion Experimental Reactor) which were picked out through the process of '86 FER scoping studies. Main concern in the electrical systems is coil power supplies which have a capacity of about 1 GW, and this is dominated by poloidal coil power supplies. Then, studies to reduce the converter capacity are concentrated on the poloidal coil power system in relation to the sypplying poloidal flux at the initial phase of plasma ramp-up. A quench protection circuit was proposed on the toroidal coil power supply. On the position control power supply, a circuit with reasonable functions was proposed. Under these system studies, general specifications were determined and the capacity of each power supply unit was estimated. On the poloidal coil power supply system, the accumulated capacity of converters amounted to 885 MW for the one candidate and 782 MW for another. (author)

Conceptual design study of fusion experimental reactor (FY86 FER)

International Nuclear Information System (INIS)

Seki, Yasushi; Iida, Hiromasa; Honda, Tsutomu.

1987-08-01

This report describes the study on safety for FER(Fusion Experimental Reactor) which has been designed as a next step machine to the JT-60. Though the final purpose of this study is to have an image of design base accident, maximum credible accident and to assess their risk or probability, etc., as FER plant system, the emphasis of this years study is placed on fuel-gas circulation system where the tritium inventory is maximum. This report consists of two chapters. The first chapter of this report summaries the FER system and describes FMEA(Failure Mode and Effect Analysis) and related accident progression sequence for FER plant system as a whole. The second chapter of this report is focused on fuel-gas circulation system including the purification, isotope separation system and storage system. Here, probability of risk is assessed by the probabilistic risk analysis (PRA) procedure based on FMEA, ETA and FTA. (author)

Three-stage classical molecular dynamics model for simulation of heavy-ion fusion

Directory of Open Access Journals (Sweden)

Godre Subodh S.

2015-01-01

Full Text Available A three-stage Classical Molecular Dynamics (3S-CMD approach for heavy-ion fusion is developed. In this approach the Classical Rigid-Body Dynamics simulation for heavy-ion collision involving light deformed nucleus is initiated on their Rutherford trajectories at very large initial separation. Collision simulation is then followed by relaxation of the rigid-body constrains for one or both the colliding nuclei at distances close to the barrier when the trajectories of all the nucleons are obtained in a Classical Molecular Dynamics approach. This 3S-CMD approach explicitly takes into account not only the long range Coulomb reorientation of the deformed collision partner but also the internal vibrational excitations of one or both the nuclei at distances close to the barrier. The results of the dynamical simulation for 24Mg+208Pb collision show significant modification of the fusion barrier and calculated fusion cross sections due to internal excitations.

Complex fragment emission at low and high excitation energy

International Nuclear Information System (INIS)

Moretto, L.G.

1986-08-01

Complex fragment emission has been certified as a compound nucleus process at low energies. An extension of the measurements to heavy ion reactions up to 50 MeV/u shows that most complex fragments are emitted by highly excited compound nuclei formed in incomplete fusion reactions. 12 refs., 26 figs

Magnetic fusion energy

International Nuclear Information System (INIS)

Anon.

1978-01-01

The efforts of the Chemical Technology Division in the area of fusion energy include fuel handling, processing, and containment. These studies are closely coordinated with the ORNL Fusion Energy Division. Current experimental studies are concerned with the development of vacuum pumps for fusion reactors, the evaluation and development of techniques for recovering tritium (fuel) from either solid or liquid lithium containing blankets, and the use of deep beds of sorbents as roughing pumps and/or transfer operations. In addition, a small effort is devoted to the support of the ORNL design of The Next Step (TNS) in tokamak reactor development. The more applied studies--vacuum pump development and TNS design--are funded by the DOE/Magnetic Fusion Energy, and the more fundamental studies--blanket recovery and sorption in deep beds--are funded by the DOE/Basic Energy Sciences

FENIX [Fusion ENgineering International eXperimental]: A test facility for ITER [International Thermonuclear Experimental Reactor] and other new superconducting magnets

International Nuclear Information System (INIS)

Slack, D.S.; Patrick, R.E.; Miller, J.R.

1990-01-01

The Fusion ENgineering International eXperimental (FENIX) Test Facility which is nearing completion at Lawrence Livermore National Laboratory, is a 76-t set of superconducting magnets housed in a 4-m-diameter cryostat. It represents a significant step toward meeting the testing needs for the development of superconductors appropriate for large-scale magnet applications such as the International Thermonuclear Experimental Reactor (ITER). The magnet set is configured to allow radial access to the 0.4-m-diameter high-field region where maximum fields up to 14 T will be provided. The facility is fitted with a thermally isolated test well with a port to the high-field region that allows insertion and removal of test conductors without disturbing the cryogenic environment of the magnets. It is expected that the facility will be made available to magnet developers internationally, and this paper discusses its general design features, its construction, and its capabilities

Coulomb excitation of $^{110}$Sn using REX-ISOLDE

CERN Document Server

Ekström, A; Hurst, A; Fahlander, C; Banu, A; Butler, P; Eberth, J; Górska, M; Habs, D; Huyse, M; Kester, O; Niedermayer, O; Nilsson, T; Pantea, M; Scheit, H; Schwalm, D; Sletten, G; Ushasi, D P; Van Duppen, P; Warr, N; Weisshaar, D

2006-01-01

In this paper, we report the preliminary result from the first Coulomb excitation experiment at REX-ISOLDE (Habs et al 1998 Nucl. Instrum. Methods B 139 128) using neutron-deficient Sn-beams. The motivation of the experiment is to deduce the reduced transition probability, B(E2 ; 2$^+\\rightarrow$ 0$^+$) , for the sequence of neutron deficient, unstable, even-even Sn-isotopes from using a radioactive beam opens up a new path to study the lifetime of the first excited 2$^+$ state in these isotopes. The de-excitation path following fusion-evaporation reactions will for the even-even Sn isotopes pass via an isomeric 6$^+$ state, located at higher energy, which thus hampers measurements of the lifetime of the first excited state using, e.g., recoil-distance methods. For this reason the reduced transition probability of the first excited 2$^+$ state has remained unknown in this chain of isotopes although the B(E2) value of the stable isotope $^{112}$Sn was measured approximately 30 years ago (see, e.g., Stelson et...

Is the anomalous effect an experimental evidence for the excitation of new exotic states in heavy-ion collisions

International Nuclear Information System (INIS)

Ion, D.B.; Ion, R.; Topor Pop, V.

1984-10-01

Lower bound on the mean free path of the projectile fragments from the relativistic heavy ion collisions are drived using generalized Rarita-Schwed's theorems. These bounds are compared with the experimental data on the anomalous mean free path observed in recent experiments. The near saturation of these bounds provide a specific interpretation of the anomalous effects as an experimental evidence for the excitation of those extreme nuclear states which saturate the limits of the convetional nuclear physics. (authors)

Effect of breakup on near barrier fusion

International Nuclear Information System (INIS)

Dasgupta, M.; Berriman, A.C.; Butt, R.D.; Hinde, D.J.; Morton, C.R.; Newton, J.O.

2000-01-01

Full text: Unstable neutron-rich nuclei having very weakly bound neutrons exhibit characteristic features such as a neutron halo extending to large radii, and a low energy threshold for breakup. These features may dramatically affect fusion and other reaction processes. It is well accepted that the extended nuclear matter distribution will lead to an enhancement in fusion cross-sections over those for tightly bound nuclei. The effect of couplings to channels which act as doorways to breakup is, however, controversial, with model predictions differing in the relative magnitudes of enhancement and suppression. To investigate the effect on fusion of couplings specific to unstable neutron-rich nuclei, it is necessary to understand (and then predict) the cross-sections expected for their stable counterparts. This requires knowledge of the energy of the average fusion barrier, and information on the couplings. Experimentally all this information can be obtained from precisely measured fusion cross-sections. Such precision measurements of complete fusion cross-sections for 9 Be + 208 Pb and 6 Li, 7 Li + 209 Bi systems have been done at the Australian National University. The distribution of fusion barriers extracted from these data were used to reliably predict the expected fusion cross-sections. Comparison of the theoretical expectations with the experimentally measured cross-sections show conclusively that complete fusion, at above barrier energies, for all three systems is suppressed (by about 30%) compared with the fusion of more tightly bound nuclei. These measurements, in conjunction with incomplete fusion cross-sections, which were also measured, should encourage a complete theoretical description of fusion and breakup

Helios, a 20 TW CO2 laser fusion facility

International Nuclear Information System (INIS)

Ladish, J.S.

1979-01-01

Since June 1978 the Los Alamos Scientific Laboratory's Helios CO 2 laser fusion facility has been committed to an experimental target program to investigate the feasibility of laser produced inertial confinement fusion. This system is briefly described, and preliminary experimental results are reported

Myoblast fusion in Drosophila

Energy Technology Data Exchange (ETDEWEB)

Haralalka, Shruti [Stowers Institute for Medical Research, Kansas City, MO 64110 (United States); Abmayr, Susan M., E-mail: sma@stowers.org [Stowers Institute for Medical Research, Kansas City, MO 64110 (United States); Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, MO 66160 (United States)

2010-11-01

The body wall musculature of a Drosophila larva is composed of an intricate pattern of 30 segmentally repeated muscle fibers in each abdominal hemisegment. Each muscle fiber has unique spatial and behavioral characteristics that include its location, orientation, epidermal attachment, size and pattern of innervation. Many, if not all, of these properties are dictated by founder cells, which determine the muscle pattern and seed the fusion process. Myofibers are then derived from fusion between a specific founder cell and several fusion competent myoblasts (FCMs) fusing with as few as 3-5 FCMs in the small muscles on the most ventral side of the embryo and as many as 30 FCMs in the larger muscles on the dorsal side of the embryo. The focus of the present review is the formation of the larval muscles in the developing embryo, summarizing the major issues and players in this process. We have attempted to emphasize experimentally-validated details of the mechanism of myoblast fusion and distinguish these from the theoretically possible details that have not yet been confirmed experimentally. We also direct the interested reader to other recent reviews that discuss myoblast fusion in Drosophila, each with their own perspective on the process . With apologies, we use gene nomenclature as specified by Flybase (http://flybase.org) but provide Table 1 with alternative names and references.

Myoblast fusion in Drosophila

International Nuclear Information System (INIS)

Haralalka, Shruti; Abmayr, Susan M.

2010-01-01

The body wall musculature of a Drosophila larva is composed of an intricate pattern of 30 segmentally repeated muscle fibers in each abdominal hemisegment. Each muscle fiber has unique spatial and behavioral characteristics that include its location, orientation, epidermal attachment, size and pattern of innervation. Many, if not all, of these properties are dictated by founder cells, which determine the muscle pattern and seed the fusion process. Myofibers are then derived from fusion between a specific founder cell and several fusion competent myoblasts (FCMs) fusing with as few as 3-5 FCMs in the small muscles on the most ventral side of the embryo and as many as 30 FCMs in the larger muscles on the dorsal side of the embryo. The focus of the present review is the formation of the larval muscles in the developing embryo, summarizing the major issues and players in this process. We have attempted to emphasize experimentally-validated details of the mechanism of myoblast fusion and distinguish these from the theoretically possible details that have not yet been confirmed experimentally. We also direct the interested reader to other recent reviews that discuss myoblast fusion in Drosophila, each with their own perspective on the process . With apologies, we use gene nomenclature as specified by Flybase (http://flybase.org) but provide Table 1 with alternative names and references.

Sub-Coulomb fusion with halo nuclei

International Nuclear Information System (INIS)

Fekou-Youmbi, V.; Sida, J.L.; Alamanos, N.; Auger, F.; Bazin, D.; Borcea, C.; Cabot, C.; Cunsolo, A.; Foti, A.; Gillibert, A.; Lepine, A.; Lewitowicz, M.; Liguori-Neto, R.; Mittig, W.; Pollacco, E.; Roussel-Chomaz, P.; Volant, C.; Yong Feng, Y.

1995-01-01

The nuclear structure of halo nuclei may have strong influence on the fusion cross section at sub-barrier energies. The actual theoretical debate is briefly reviewed and sub-barrier fusion calculations for the system 11 Be+ 238 U are presented. An experimental program on sub-barrier fusion for the systems 7,9,10,11 Be+ 238 U is underway at GANIL. First results with 9 Be and 11 Be beams were obtained using the F.U.S.ION detector. Relative fission cross sections are presented. ((orig.))

Saturated excitation of Fluorescence to quantify excitation enhancement in aperture antennas

KAUST Repository

Aouani, Heykel

2012-07-23

Fluorescence spectroscopy is widely used to probe the electromagnetic intensity amplification on optical antennas, yet measuring the excitation intensity amplification is a challenge, as the detected fluorescence signal is an intricate combination of excitation and emission. Here, we describe a novel approach to quantify the electromagnetic amplification in aperture antennas by taking advantage of the intrinsic non linear properties of the fluorescence process. Experimental measurements of the fundamental f and second harmonic 2f amplitudes of the fluorescence signal upon excitation modulation are used to quantify the electromagnetic intensity amplification with plasmonic aperture antennas. © 2012 Optical Society of America.

Saturated excitation of Fluorescence to quantify excitation enhancement in aperture antennas

KAUST Repository

Aouani, Heykel; Hostein, Richard; Mahboub, Oussama; Devaux, Eloï se; Rigneault, Hervé ; Ebbesen, Thomas W.; Wenger, Jé rô me

2012-01-01

Fluorescence spectroscopy is widely used to probe the electromagnetic intensity amplification on optical antennas, yet measuring the excitation intensity amplification is a challenge, as the detected fluorescence signal is an intricate combination of excitation and emission. Here, we describe a novel approach to quantify the electromagnetic amplification in aperture antennas by taking advantage of the intrinsic non linear properties of the fluorescence process. Experimental measurements of the fundamental f and second harmonic 2f amplitudes of the fluorescence signal upon excitation modulation are used to quantify the electromagnetic intensity amplification with plasmonic aperture antennas. © 2012 Optical Society of America.

Isotopic effects in sub-barrier fusion of Si + Si systems

Science.gov (United States)

Colucci, G.; Montagnoli, G.; Stefanini, A. M.; Esbensen, H.; Bourgin, D.; Čolović, P.; Corradi, L.; Faggian, M.; Fioretto, E.; Galtarossa, F.; Goasduff, A.; Grebosz, J.; Haas, F.; Mazzocco, M.; Scarlassara, F.; Stefanini, C.; Strano, E.; Szilner, S.; Urbani, M.; Zhang, G. L.

2018-04-01

Background: Recent measurements of fusion cross sections for the 28Si+28Si system revealed a rather unsystematic behavior; i.e., they drop faster near the barrier than at lower energies. This was tentatively attributed to the large oblate deformation of 28Si because coupled-channels (CC) calculations largely underestimate the 28Si+28Si cross sections at low energies, unless a weak imaginary potential is applied, probably simulating the deformation. 30Si has no permanent deformation and its low-energy excitations are of a vibrational nature. Previous measurements of this system reached only 4 mb, which is not sufficient to obtain information on effects that should show up at lower energies. Purpose: The aim of the present experiment was twofold: (i) to clarify the underlying fusion dynamics by measuring the symmetric case 30Si+30Si in an energy range from around the Coulomb barrier to deep sub-barrier energies, and (ii) to compare the results with the behavior of 28Si+28Si involving two deformed nuclei. Methods: 30Si beams from the XTU tandem accelerator of the Laboratori Nazionali di Legnaro of the Istituto Nazionale di Fisica Nucleare were used, bombarding thin metallic 30Si targets (50 μ g /cm2) enriched to 99.64 % in mass 30. An electrostatic beam deflector allowed the detection of fusion evaporation residues (ERs) at very forward angles, and angular distributions of ERs were measured. Results: The excitation function of 30Si+30Si was measured down to the level of a few microbarns. It has a regular shape, at variance with the unusual trend of 28Si+28Si . The extracted logarithmic derivative does not reach the LCS limit at low energies, so that no maximum of the S factor shows up. CC calculations were performed including the low-lying 2+ and 3- excitations. Conclusions: Using a Woods-Saxon potential the experimental cross sections at low energies are overpredicted, and this is a clear sign of hindrance, while the calculations performed with a M3Y + repulsion

Probing of complete and incomplete fusion dynamics in heavy-ion ...

Indian Academy of Sciences (India)

2014-04-04

Apr 4, 2014 ... Heavy-ion induced reactions; complete and incomplete fusion; ... CF reaction the projectile completely fuses with the target nucleus and the highly excited .... input parameters have been used as default except the charge and ...

An Experimental Validated Control Strategy of Maglev Vehicle-Bridge Self-Excited Vibration

Directory of Open Access Journals (Sweden)

Lianchun Wang

2017-01-01

Full Text Available This study discusses an experimentally validated control strategy of maglev vehicle-bridge vibration, which degrades the stability of the suspension control, deteriorates the ride comfort, and limits the cost of the magnetic levitation system. First, a comparison between the current-loop and magnetic flux feedback is carried out and a minimum model including flexible bridge and electromagnetic levitation system is proposed. Then, advantages and disadvantages of the traditional feedback architecture with the displacement feedback of electromagnet yE and bridge yB in pairs are explored. The results indicate that removing the feedback of the bridge’s displacement yB from the pairs (yE − yB measured by the eddy-current sensor is beneficial for the passivity of the levitation system and the control of the self-excited vibration. In this situation, the signal acquisition of the electromagnet’s displacement yE is discussed for the engineering application. Finally, to validate the effectiveness of the aforementioned control strategy, numerical validations are carried out and the experimental data are provided and analyzed.

Opportunities in the Fusion Energy Sciences Program [Includes Appendix C: Topical Areas Characterization

Energy Technology Data Exchange (ETDEWEB)

None

1999-06-01

Recent years have brought dramatic advances in the scientific understanding of fusion plasmas and in the generation of fusion power in the laboratory. Today, there is little doubt that fusion energy production is feasible. The challenge is to make fusion energy practical. As a result of the advances of the last few years, there are now exciting opportunities to optimize fusion systems so that an attractive new energy source will be available when it may be needed in the middle of the next century. The risk of conflicts arising from energy shortages and supply cutoffs, as well as the risk of severe environmental impacts from existing methods of energy production, are among the reasons to pursue these opportunities.

Theoretical and Experimental Study on Synchronization of the Two Homodromy Exciters in a Non-Resonant Vibrating System

Directory of Open Access Journals (Sweden)

Xue-Liang Zhang

2013-01-01

Full Text Available In this paper we give some theoretical analyses and experimental results on synchronization of the two non-identical exciters. Using the average method of modified small parameters, the dimensionless coupling equation of the two exciters is deduced. The synchronization criterion for the two exciters is derived as the torque of frequency capture being equal to or greater than the absolute value of difference between the residual electromagnetic torques of the two motors. The stability criterion of synchronous state is verified to satisfy the Routh-Hurwitz criterion. The regions of implementing synchronization and that of stability of phase difference for the two exciters are manifested by numeric method. Synchronization of the two exciters stems from the coupling dynamic characteristic of the vibrating system having selecting motion, especially, under the condition that the parameters of system are complete symmetry, the torque of frequency capture stemming from the circular motion of the rigid frame drives the phase difference to approach PI and carry out the swing of the rigid frame; that from the swing of the rigid frame forces the phase difference to near zero and achieve the circular motion of the rigid frame. In the steady state, the motion of rigid frame will be one of three types: pure swing, pure circular motion, swing and circular motion coexistence. The numeric and experiment results derived thereof show that the two exciters can operate synchronously as long as the structural parameters of system satisfy the criterion of stability in the regions of frequency capture. In engineering, the distance between the centroid of the rigid frame and the rotational centre of exciter should be as far as possible. Only in this way, can the elliptical motion of system required in engineering be realized.

Fusion hindrance in reactions with very heavy ions: Border between normal and hindered fusion

International Nuclear Information System (INIS)

Shen Caiwan; Li Qingfeng; Boilley, David; Shen Junjie; Abe, Yasuhisa

2011-01-01

The fusion hindrance in heavy-ion collisions is studied in the framework of the two-center liquid drop model. It appears that the neck and the radial degrees of freedom might both be hampered by an inner potential barrier on their path between the contact configuration to the compound nucleus. Heavy-ion reactions with and without the two kinds of fusion hindrance are classified through systematic calculations. It is found that the number of reactions without radial fusion hindrance is much smaller than that without neck fusion hindrance, and for both kinds of fusion hindrance the number of reactions without fusion hindrance at small mass-asymmetry parameter α is smaller than that at large α. In the formation of a given compound nucleus, if a reaction with α c is not hindered, then other reactions with α>α c are also not hindered, as is well known experimentally.

Analysis of Consequences in the Loss-of-Coolant Accident in Wendelstein 7-X Experimental Nuclear Fusion Facility

Energy Technology Data Exchange (ETDEWEB)

Uspuras, E., E-mail: algis@mail.lei.lt [Laboratory of Nuclear Installations Safety, Lithuanian Energy Institute, Kaunas (Lithuania)

2012-09-15

Full text: Fusion is the energy production technology, which could potentially solve problems with growing energy demand of population in the future. Starting 2007, Lithuanian energy institute (LEI) is a member of European Fusion Development Agreement (EFDA) organization. LEI is cooperating with Max Planck Institute for Plasma Physics (IPP, Germany) in the frames of EFDA project by performing safety analysis of fusion device W7-X. Wendelstein 7-X (W7-X) is an experimental stellarator facility currently being built in Greifswald, Germany, which shall demonstrate that in the future energy could be produced in such type of fusion reactors. The W7-X facility divertor cooling system consists of two coolant circuits: the main cooling circuit and the so-called 'baking' circuit. Before plasma operation, the divertor and other invessel components must be heated up in order to 'clean' the surfaces by thermal desorption and the subsequent pumping out of the released volatile molecules. The rupture of pipe, providing water for the divertor targets during the 'baking' regime is one of the critical failure events, since primary and secondary steam production leads to a rapid increase of the inner pressure in the plasma (vacuum) vessel. Such initiating event could lead to the loss of vacuum condition up to overpressure of the plasma vessel, damage of in-vessel components and bellows of the ports. In this paper the safety analysis of 40 mm inner diameter coolant pipe rupture in cooling circuit and discharge of steam-water mixture through the leak into plasma vessel during the W7-X no-plasma 'baking' operation mode is presented. For the analysis the model of W7-X cooling system (pumps, valves, pipes, hydro-accumulators, and heat exchangers) and plasma vessel was developed by employing system thermal-hydraulic state-of-the-art RELAP5 Mod 3.3 code. This paper demonstrated, that the developed RELAP5 model allows to analyze the processes in divertor cooling system and plasma vessel

The role of the dinuclear system in the processes of nuclear fusion, quasi-fission, fission and cluster formation

International Nuclear Information System (INIS)

Volkov, V.V.

1999-01-01

The nuclear fusion, quasi-fission, fission and cluster formation in an excited nucleus are considered as the processes of the formation and evolution of the dinuclear system. This approach allows one to reveal new aspects of nuclear fusion, to show that quasi-fission plays an important role in nuclear reactions used to synthesise superheavy elements. A qualitative picture is given of the fission process of an excited nucleus and an important role of cluster formation in this process is shown

An Experimental Investigation of the Dynamic Behavior of an In-Plane MEMS Shallow Arch Under Electrostatic Excitation

KAUST Repository

Ramini, Abdallah

2016-01-20

We present experimental investigation of the nonlinear dynamics of a clamped-clamped in-plane MEMS shallow arch when excited by an electrostatic force. We explore the dynamic behaviors of the in-plane motion of the shallow arches via frequency sweeps in the neighborhood of the first resonance frequency. The shallow arch response is video microscopy recorded and analyzed by means of digital imaging. The experimental data show local softening behavior for small DC and AC loads. For high voltages, the experimental investigation reveals interesting dynamics, where the arch exhibits a dynamic snap-Through behavior. These attractive experimental results verify the previously reported complex behavior of in-plane MEMS arches and show promising results to implement these structures for variety of sensing and actuation applications. © Copyright 2015 by ASME.

Numerical and Experimental Study of Ti6Al4V Components Manufactured Using Powder Bed Fusion Additive Manufacturing

Science.gov (United States)

Zielinski, Jonas; Mindt, Hans-Wilfried; Düchting, Jan; Schleifenbaum, Johannes Henrich; Megahed, Mustafa

2017-12-01

Powder bed fusion additive manufacturing of titanium alloys is an interesting manufacturing route for many applications requiring high material strength combined with geometric complexity. Managing powder bed fusion challenges, including porosity, surface finish, distortions and residual stresses of as-built material, is the key to bringing the advantages of this process to production main stream. This paper discusses the application of experimental and numerical analysis towards optimizing the manufacturing process of a demonstration component. Powder characterization including assessment of the reusability, assessment of material consolidation and process window optimization is pursued prior to applying the identified optima to study the distortion and residual stresses of the demonstrator. Comparisons of numerical predictions with measurements show good correlations along the complete numerical chain.

Experimental study of precisely selected evaporation chains in the decay of excited 25Mg

Science.gov (United States)

Camaiani, A.; Casini, G.; Morelli, L.; Barlini, S.; Piantelli, S.; Baiocco, G.; Bini, M.; Bruno, M.; Buccola, A.; Cinausero, M.; Cicerchia, M.; D'Agostino, M.; Degelier, M.; Fabris, D.; Frosin, C.; Gramegna, F.; Gulminelli, F.; Mantovani, G.; Marchi, T.; Olmi, A.; Ottanelli, P.; Pasquali, G.; Pastore, G.; Valdré, S.; Verde, G.

2018-04-01

The reaction 12C+13C at 95 MeV bombarding energy is studied using the Garfield + Ring Counter apparatus located at the INFN Laboratori Nazionali di Legnaro. In this paper we want to investigate the de-excitation of 25Mg aiming both at a new stringent test of the statistical description of nuclear decay and a direct comparison with the decay of the system 24Mg formed through 12C+12C reactions previously studied. Thanks to the large acceptance of the detector and to its good fragment identification capabilities, we could apply stringent selections on fusion-evaporation events, requiring their completeness in charge. The main decay features of the evaporation residues and of the emitted light particles are overall well described by a pure statistical model; however, as for the case of the previously studied 24Mg, we observed some deviations in the branching ratios, in particular for those chains involving only the evaporation of α particles. From this point of view the behavior of the 24Mg and 25Mg decay cases appear to be rather similar. An attempt to obtain a full mass balance even without neutron detection is also discussed.

Comparative study of the excitation functions of nuclear reactions induced by light ions (protons and α) and heavy ions (Ne, Ca, Ar) and, after neutron evaporation, leading to platinum and polonium isotopes. Analysis by de-excitation programme allowing for the angular momentum and fission

International Nuclear Information System (INIS)

Lagarde, Brigitte.

1979-01-01

This work is a study on the de-excitation of heavy nuclei from the Pt - Po area obtained by the complete fusion of various projectiles (p, 3 He, 4 He, 20 Ne, 40 Ar and 40 Ca) and of various targets. The aim was to create from different couples the same compound nucleus of a mass equal to the sum of the masses of the component parts. The excitation energy of the system thus created can vary between 60 and 120 MeV. The experimental study of one or more particular de-excitation channels performed by measuring the cross sections of residual nuclei production for various bombardment energies is a very conventional approach. An in depth examination was made of the effect of the angular momentum given to the compound nucleus by the input channel to the de-excitation processes. Now the population of orbital angular momenta depends essentially on the mass of the projectile at equal velocities. Consequently, the utilization of projectiles extending from the proton to mass 40 covers a wide range. Decay by neutrons is not the only de-excitation method. Fission has a significant role particularly for the Po's and consequently this strongly diminishes the probability (P,xn). The decay of (α,xn) when going from the compound nucleus of 204 Po to 182 Pt makes it possble to evaluate the importance of the phenomenon and to have an item of experimental information that can be compared to a theoretical calculation. Theoretical calculations using the 'ALICE' code which expresses schematically the reduction in level densities by subtracting from the excitation energy a rotation energy and the 'JULIAN' code which uses a more accurate level density calculation and takes into account the gamma emission competing with the emission of neutrons show that the last programme reports the experimental results whereas the 'ALICE' code does not enable a consistent presentation to be made of all the results by light and heavy ions. Finally, it had to be agreed that the fission does not intervene as

Inertial fusion sciences and applications 99: state of the art 1999

International Nuclear Information System (INIS)

Labaune, Ch.; Hogan, W.J.; Tanaka, K.A.

2000-01-01

This book brings together the texts of the communications presented at the conference 'Inertial fusion sciences and applications' held in Paris in 1999. These proceedings are shared into five sessions: laser fusion physics, fusion with particle beams, fusion with implosions, inertial fusion energy, and experimental applications of inertial fusion. (J.S.)

Influence of fusion dynamics on fission observables: A multidimensional analysis

Science.gov (United States)

Schmitt, C.; Mazurek, K.; Nadtochy, P. N.

2018-01-01

An attempt to unfold the respective influence of the fusion and fission stages on typical fission observables, and namely the neutron prescission multiplicity, is proposed. A four-dimensional dynamical stochastic Langevin model is used to calculate the decay by fission of excited compound nuclei produced in a wide set of heavy-ion collisions. The comparison of the results from such a calculation and experimental data is discussed, guided by predictions of the dynamical deterministic HICOL code for the compound-nucleus formation time. While the dependence of the latter on the entrance-channel properties can straigthforwardly explain some observations, a complex interplay between the various parameters of the reaction is found to occur in other cases. A multidimensional analysis of the respective role of these parameters, including entrance-channel asymmetry, bombarding energy, compound-nucleus fissility, angular momentum, and excitation energy, is proposed. It is shown that, depending on the size of the system, apparent inconsistencies may be deduced when projecting onto specific ordering parameters. The work suggests the possibility of delicate compensation effects in governing the measured fission observables, thereby highlighting the necessity of a multidimensional discussion.

An Overview of INEL Fusion Safety R&D Facilities

Science.gov (United States)

McCarthy, K. A.; Smolik, G. R.; Anderl, R. A.; Carmack, W. J.; Longhurst, G. R.

1997-06-01

The Fusion Safety Program at the Idaho National Engineering Laboratory has the lead for fusion safety work in the United States. Over the years, we have developed several experimental facilities to provide data for fusion reactor safety analyses. We now have four major experimental facilities that provide data for use in safety assessments. The Steam-Reactivity Measurement System measures hydrogen generation rates and tritium mobilization rates in high-temperature (up to 1200°C) fusion relevant materials exposed to steam. The Volatilization of Activation Product Oxides Reactor Facility provides information on mobilization and transport and chemical reactivity of fusion relevant materials at high temperature (up to 1200°C) in an oxidizing environment (air or steam). The Fusion Aerosol Source Test Facility is a scaled-up version of VAPOR. The ion-implanta-tion/thermal-desorption system is dedicated to research into processes and phenomena associated with the interaction of hydrogen isotopes with fusion materials. In this paper we describe the capabilities of these facilities.

Single photon simultaneous K-shell ionization and K-shell excitation. I. Theoretical model applied to the interpretation of experimental results on H2O

International Nuclear Information System (INIS)

Carniato, S.; Selles, P.; Andric, L.; Palaudoux, J.; Penent, F.; Lablanquie, P.; Žitnik, M.; Bučar, K.; Nakano, M.; Hikosaka, Y.; Ito, K.

2015-01-01

We present in detail a theoretical model that provides absolute cross sections for simultaneous core-ionization core-excitation (K −2 V ) and compare its predictions with experimental results obtained on the water molecule after photoionization by synchrotron radiation. Two resonances of different symmetries are assigned in the main K −2 V peak and comparable contributions from monopolar (direct shake-up) and dipolar (conjugate shake-up) core-valence excitations are identified. The main peak is observed with a much greater width than the total experimental resolution. This broadening is the signature of nuclear dynamics

Laser fusion experiments at LLL

Energy Technology Data Exchange (ETDEWEB)

Ahlstrom, H.G.

1980-06-16

These notes present the experimental basis and status for laser fusion as developed at LLL. Two other chapters, one authored by K.A. Brueckner and the other by C. Max, present the theoretical implosion physics and laser plasma interaction physics. The notes consist of six sections. The first is an introductory section which provides some of the history of inertial fusion and a simple explanation of the concepts involved. The second section presents an extensive discussion of diagnostic instrumentation used in the LLL Laser Fusion Program. The third section is a presentation of laser facilities and capabilities at LLL. The purpose here is to define capability, not to derive how it was obtained. The fourth and fifth sections present the experimental data on laser-plasma interaction and implosion physics. The last chapter is a short projection of the future.

Laser fusion experiments at LLL

International Nuclear Information System (INIS)

Ahlstrom, H.G.

1980-01-01

These notes present the experimental basis and status for laser fusion as developed at LLL. Two other chapters, one authored by K.A. Brueckner and the other by C. Max, present the theoretical implosion physics and laser plasma interaction physics. The notes consist of six sections. The first is an introductory section which provides some of the history of inertial fusion and a simple explanation of the concepts involved. The second section presents an extensive discussion of diagnostic instrumentation used in the LLL Laser Fusion Program. The third section is a presentation of laser facilities and capabilities at LLL. The purpose here is to define capability, not to derive how it was obtained. The fourth and fifth sections present the experimental data on laser-plasma interaction and implosion physics. The last chapter is a short projection of the future

On Korean strategy and plan for fusion energy

International Nuclear Information System (INIS)

Kim, H.J.; Choi, W-J.; Park, C.; Kim, H.C.

2012-01-01

In developing KSTAR (Korean Superconducting Tokamak Advanced Research), Korea had initiated a mid-entry strategy to catch up with the technologies required for the development of a fusion reactor, based on the tokamak magnetic confinement concept. Upon joining ITER (International Thermonuclear Experimental Reactor), Korean government enacted a promotional law for the fusion energy development. Under this promotional law the national promotional plans for developing fusion energy have been established. The National Fusion Research Institute (NFRI) developed the strategy and plan for a fusion DEMO program to realize the magnetic fusion energy. (author)

On Korean strategy and plan for fusion energy

Energy Technology Data Exchange (ETDEWEB)

Kim, H.J. [National Fusion Research Inst., Daejeon (Korea, Republic of); Choi, W-J. [Chungnam National Univ., Daejeon (Korea, Republic of); Park, C. [POSTECH, Pohang (Korea, Republic of); Kim, H.C. [National Fusion Research Inst., Daejeon (Korea, Republic of)

2012-07-01

In developing KSTAR (Korean Superconducting Tokamak Advanced Research), Korea had initiated a mid-entry strategy to catch up with the technologies required for the development of a fusion reactor, based on the tokamak magnetic confinement concept. Upon joining ITER (International Thermonuclear Experimental Reactor), Korean government enacted a promotional law for the fusion energy development. Under this promotional law the national promotional plans for developing fusion energy have been established. The National Fusion Research Institute (NFRI) developed the strategy and plan for a fusion DEMO program to realize the magnetic fusion energy. (author)

Study of the angular momentum distribution of compound nuclei obtained from fusion reactions close to the Coulomb barrier

International Nuclear Information System (INIS)

Romain, P.

1990-03-01

The effect of the mass asymmetry of the input channel on the compound nuclei spin distribution. The 16 O + 144 Nd and 80 Se + 80 Se reactions produce the same 160 Er compound nucleus in the 38 to 68 MeV energy range. In certain cases, the incident energies required to form the compound nucleus, at the same excitation energies, are very close to the Coulomb barrier. In the experimental device, the 'Chateau de Cristal' multidetector and additional sensors are used. The angular momentum distribution of the different evaporation products are measured by gamma spectrometry techniques. The fusion cross sections are measured by the time-of-flight technique. Theoretical predictions and experimental results concerning the distribution of the compound nucleus angular momentum are compared [fr

Course/workshop on muon catalyzed fusion and fusion with polarized nuclei

International Nuclear Information System (INIS)

Kulsrud, R.M.

1987-08-01

There seems to be some real connection between the spin states of the d-t nuclei in the muon mesomolecule dtμ and the resultant sticking probability. This paper discusses this connection. No new experimental results on spin polarization are reported, but illuminating ideas emerged as to the role spin polarized plasmas could play in inertial confinement fusion and magnetic fusion. In addition, realistic evaluations were made as to the possibility of producing and preserving spin polarized plasmas. 4 refs

World progress toward fusion energy

International Nuclear Information System (INIS)

Clarke, J.F.

1989-09-01

This paper will describe the progress in fusion science and technology from a world perspective. The paper will cover the current technical status, including the understanding of fusion's economic, environmental, and safety characteristics. Fusion experiments are approaching the energy breakeven condition. An energy gain (Q) of 30 percent has been achieved in magnetic confinement experiments. In addition, temperatures required for an ignited plasma (Ti = 32 KeV) and energy confinements about 75 percent of that required for ignition have been achieved in separate experiments. Two major facilities have started the experimental campaign to extend these results and achieve or exceed Q = 1 plasma conditions by 1990. Inertial confinement fusion experiments are also approaching thermonuclear conditions and have achieved a compression factor 100-200 times liquid D-T. Because of this progress, the emphasis in fusion research is turning toward questions of engineering feasibility. Leaders of the major fusion R and D programs in the European Community (EC), Japan, the United States, and the U.S.S.R. have agreed on the major steps that are needed to reach the point at which a practical fusion system can be designed. The United States is preparing for an experiment to address the last unexplored scientific issue, the physics of an ignited plasma, during the late 1990's. The EC, Japan, U.S.S.R., and the United States have joined together under the auspices of the International Atomic Energy Agency (IAEA) to jointly design and prepare the validating R and D for an international facility, the International Thermonuclear Experimental Reactor (ITER), to address all the remaining scientific issues and to explore the engineering technology of fusion around the turn of the century. In addition, a network of international agreements have been concluded between these major parties and a number of smaller fusion programs, to cooperate on resolving a complete spectrum of fusion science and

Experimental study on the kinetically induced electronic excitation in atomic collisional cascades

International Nuclear Information System (INIS)

Meyer, S.

2006-01-01

the present thesis deals with the ion-collision-induced electronic excitation of metallic solids. For this for the first time metal-insulator-metal layer systems are used for the detection of this electronic excitation. The here applied aluminium/aluminium oxide/silver layer sytems have barrier heights of 2.4 eV on the aluminium respectively 3.3 eV on the silver side. With the results it could uniquely be shown that the electronic excitation is generated by kinetic processes, this excitation dependenc on the kinetic energy of the colliding particles, and the excitation dependes on the charge state of the projectile

The library of evaluated and experimental data on charged particles for fusion application (SaBa). Summary documentation

International Nuclear Information System (INIS)

Zvenigorodskij, A.G.; Zherebtsov, V.A.; Lazarev, L.M.; Dunaeva, S.A.; Generalov, L.N.; Taova, S.M.; Kamskaya, E.V.; Marshalkina, R.I.

1999-01-01

An electronic version of the evaluated and experimental data on charged particles for thermonuclear applications (SaBa) was prepared on the base of handbook 'Nuclear Physics Constants for Thermonuclear Fusion', INDC(CCP)-326/L+F, Vienna, 1991. Data on 100 channels for 52 reactions are presented in the Library. Program code was performed using the object-oriented programming environment Borland C ++ Builder for Microsoft Windows 95 and Windows NT operating systems. Optimal set of data processing procedures and friendly interface provide remarkable possibilities for the active use of this program for various applications in the field of thermonuclear fusion. It is available online (http:/www-nds.iaea.or.at/reports/data/saba/disk1.zip, ../disk2.zip, ../disk3.zip, on CD-ROM or on a set of PC diskettes from the IAEA Nuclear Data Section, costfree, upon request. (author)

Excitation of giant resonances in heavy ion collisions

International Nuclear Information System (INIS)

Kuehn, W.

1991-01-01

Introduction: What are Giant Resonances? General Features of Giant Resonances, Macroscopic Description and Classification, Basic Excitation Mechanisms, Decay Modes, Giant Resonances Built on Excited States, Relativistic Coulomb Excitation of Giant Resonances, Experimental Situation. (orig.)

Efficient channel-plasmon excitation by nano-mirrors

DEFF Research Database (Denmark)

Radko, Ilya P.; Stær, Tobias Holmgaard; Han, Zhanghua

2011-01-01

We demonstrate a configuration for efficient channel-plasmon mode excitation using tapered terminations of V-shaped groove waveguides. The plasmon excitation is achieved by directly illuminating tapers of gold V-grooves with a focused laser beam, incident normally onto the sample surface. For near......-infrared wavelengths, we find experimentally as well as numerically, by conducting three-dimensional finite-difference time-domain calculations, that the efficiency of channel-plasmon mode excitation exceeds 10% in the optimum configuration, which is the highest experimentally observed efficiency of coupling from free-propagation...

Neutron emission as a probe of fusion-fission and quasi-fission dynamics

International Nuclear Information System (INIS)

Hinde, D.J.

1991-01-01

Pre- and post scission neutron yeilds have been measured as a function of projectile mass, compound nucleus fissility, and fission mass-split and total kinetic energy (TKE) for 27 fusion-fission and quasi-fission reactions induced by beams of 16,18 O, 40 Ar and 64 Ni. A new method of interpretation of experimental pre-scission neutron multiplicities ν-pre and mean kinetic energies ε ν allows the extraction of fission time scales with much less uncertainty than previously, all fusion-fission results being consistent with a dynamical time scale of (35±15) x 10 -21 s for symmetric fission. All reactions show that ν-pre falls quite rapidly with increasing mass-asymmetry; evidence is presented that for fusion-fission reactions this is partly due to a reduction of the dynamical fission time scale with mass-asymmetry. For quasi-fission, the data indicate that the pre-scission multiplicity and mean neutron kinetic energy are very sensitive to the final mass-asymmetry, but that the time scale is virtually independent of mass-asymmetry. It is concluded that for fusion-fission there is no dependence of ν-pre on TKE, whilst for 64 Ni-induced quasi-fission reactions, a strong increase of ν-pre with decreasing TKE is observed, probably largely caused by neutron emission during the acceleration time of the fission fragments in these fast reactions. Interpretation of post-scission multiplicities in terms of fragment excitation energies leads to deduced time scales consistent with those determined from the pre-scission data. 54 refs., 17 tabs., 25 figs

Experimental and analytical study on vibration control effects of eddy-current tuned mass dampers under seismic excitations

Science.gov (United States)

Lu, Zheng; Huang, Biao; Zhang, Qi; Lu, Xilin

2018-05-01

Eddy-current tuned mass dampers (EC-TMDs) are non-contacting passive control devices and are developed on the basis of conventional tuned mass dampers. They comprise a solid mass, a stiffness element, and a damping element, wherein the damping mechanism originates from eddy currents. By relative motion between a non-magnetic conductive metal and a permanent magnet in a dynamic system, a time-varying magnetic field is induced in the conductor, thereby generating eddy currents. The eddy currents induce a magnetic field with opposite polarity, causing repulsive forces, i.e., damping forces. This technology can overcome the drawbacks of conventional tuned mass dampers, such as limited service life, deterioration of mechanical properties, and undesired additional stiffness. The experimental and analytical study of this system installed on a multi-degree-of-freedom structure is presented in this paper. A series of shaking table tests were conducted on a five-story steel-frame model with/without an EC-TMD to evaluate the effectiveness and performance of the EC-TMD in suppressing the vibration of the model under seismic excitations. The experimental results show that the EC-TMD can effectively reduce the displacement response, acceleration response, interstory drift ratio, and maximum strain of the columns under different earthquake excitations. Moreover, an analytical method was proposed on the basis of electromagnetic and structural dynamic theories. A comparison between the test and simulation results shows that the simulation method can be used to estimate the response of structures with an EC-TMD under earthquake excitations with acceptable accuracy.

A light water excess heat reaction suggests that cold fusion may be alkali-hydrogen fusion

International Nuclear Information System (INIS)

Bush, R.T.

1992-01-01

This paper reports that Mills and Kneizys presented data in support of a light water excess heat reaction obtained with an electrolytic cell highly reminiscent of the Fleischmann-Pons cold fusion cell. The claim of Mills and Kneizys that their excess heat reaction can be explained on the basis of a novel chemistry, which supposedly also explains cold fusion, is rejected in favor of their reaction being, instead, a light water cold fusion reaction. It is the first known light water cold fusion reaction to exhibit excess heat, it may serve as a prototype to expand our understanding of cold fusion. From this new reactions are deduced, including those common to past cold fusion studies. This broader pattern of nuclear reactions is typically seen to involve a fusion of the nuclides of the alkali atoms with the simplest of the alkali-type nuclides, namely, protons, deuterons, and tritons. Thus, the term alkali-hydrogen fusion seems appropriate for this new type of reaction with three subclasses: alkali-hydrogen fusion, alkali-deuterium fusion, and alkali-tritium fusion. A new three-dimensional transmission resonance model (TRM) is sketched. Finally, preliminary experimental evidence in support of the hypothesis of a light water nuclear reaction and alkali-hydrogen fusion is reported. Evidence is presented that appears to strongly implicate the transmission resonance phenomenon of the new TRM

Structures excited by heavy ions in 208Pb target. Interpretation involving giant resonances and multiphonon excitations

International Nuclear Information System (INIS)

Chomaz, P.

1984-01-01

Kinetic energy spectra of heavy fragments from the 36Ar+208Pb reaction at 11 MeV/n and 20 Ne+ 208 Pb at 30 MeV/n have been measured with a time of flight spectrometer. Numerous structures ranging up to 100 MeV excitation energy are observed in the inelastic and few nucleon transfer channels. These structures are shown to be due to an excitation of the 208 Pb target nucleus and not to decay products of excited ejectiles. Positions of low lying structures (E* 208 Pb. The linear response of the target nucleus to the external field created by the projectile is calculated microscopically in the Random Phase Approximation resolved using the Green's function method in coordinate space with a Skyrme interaction. In the independant quasi-boson approximation multiple phonon excitations reproduce the main features of the experimental data and appear as a plausible interpretation of the observed structures. The theoretical calculations and experimental observations suggest that multiphonon excitations play an important role in heavy ion reactions and contribute strongly to the kinetic energy dissipation [fr

Production of proton-rich nuclei around Z = 84-90 in fusion-evaporation reactions

Energy Technology Data Exchange (ETDEWEB)

Chen, Peng-Hui [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China); University of Chinese Academy of Sciences, Beijing (China); Feng, Zhao-Qing; Li, Jun-Qing; Jin, Gen-Ming [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Niu, Fei [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Henan Normal University, Institute of Particle and Nuclear Physics, Xinxiang (China); Guo, Ya-Fei [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China); Zhang, Hong-Fei [Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China)

2017-05-15

Within the framework of the dinuclear system model, production cross sections of proton-rich nuclei with charged numbers of Z = 84-90 are investigated systematically. Possible combinations with the {sup 28}Si, {sup 32}S, {sup 40}Ar bombarding the target nuclides {sup 165}Ho, {sup 169}Tm, {sup 170-174}Yb, {sup 175,176}Lu, {sup 174,} {sup 176-180}Hf and {sup 181}Ta are analyzed thoroughly. The optimal excitation energies and evaporation channels are proposed to produce the proton-rich nuclei. The systems are feasible to be constructed in experiments. It is found that the neutron shell closure of N = 126 is of importance during the evaporation of neutrons. The experimental excitation functions in the {sup 40}Ar induced reactions can be nicely reproduced. The charged particle evaporation is comparable with neutrons in cooling the excited proton-rich nuclei, in particular for the channels with α and proton evaporation. The production cross section increases with the mass asymmetry of colliding systems because of the decrease of the inner fusion barrier. The channels with pure neutron evaporation depend on the isotopic targets. But it is different for the channels with charged particles and more sensitive to the odd-even effect. (orig.)

Additive effects on the energy barrier for synaptic vesicle fusion cause supralinear effects on the vesicle fusion rate

DEFF Research Database (Denmark)

Schotten, Sebastiaan; Meijer, Marieke; Walter, Alexander Matthias

2015-01-01

supralinear effects on the fusion rate. To test this prediction experimentally, we developed a method to assess the number of releasable vesicles, rate constants for vesicle priming, unpriming, and fusion, and the activation energy for fusion by fitting a vesicle state model to synaptic responses induced......-linear effects of genetic/pharmacological perturbations on synaptic transmission and a novel interpretation of the cooperative nature of Ca2+-dependent release....

Fusion-fission of superheavy nuclei at low excitation energies

International Nuclear Information System (INIS)

Itkis, M.G.; Oganesyan, Yu.Ts.; Kozulin, E.M.

2000-01-01

The process of fusion-fission of superheavy nuclei with Z = 102 -122 formed in the reactions with 22 Ne, 26 Mg, 48 Ca, 58 Fe and 86 Kr ions at energies near and below the Coulomb barrier has been studied. The experiments were carried out at the U-400 accelerator of the Flerov Laboratory of Nuclear Reactions (JINR) using a time-of-flight spectrometer of fission fragments CORSET and a neutron multi-detector DEMON. As a result of the experiments, mass and energy distributions of fission fragments, fission and quasi-fission cross sections, multiplicities of neutrons and gamma-rays and their dependence on the mechanism of formation and decay of compound superheavy systems have been studied

Progress in heavy-ion drivers for inertial fusion

International Nuclear Information System (INIS)

Friedman, A.; Bangerter, R.O.; Herrmannsfeldt, W.B.

1995-01-01

This document deals with heavy-ion induction accelerators developed as fusion drivers for Inertial Confinement Fusion power. It presents the results of research aimed at developing drivers having reduced cost and size as well as the Elise accelerator being built at Lawrence Berkeley Laboratory. An experimental program at Lawrence Livermore National Laboratory concerning recirculating induction accelerators is also presented. Eventually, the document provides some information on other elements of the U.S. Heavy-Ion Fusion (HIF) research program: the experimental study of beam merging, a magnetic quadrupole development program and a study of plasma lenses. (TEC). 28 refs., 6 figs

Muon reactivation in muon-catalyzed d-t fusion from accurate p-He+ stripping and excitation cross sections

International Nuclear Information System (INIS)

Stodden, C.D.; Monkhorst, H.J.; Szalewicz, K.

1990-01-01

Accurate cross sections are obtained for the excitation and stripping of a muon from αμ in collisions with hydrogen atoms. This is done by calculating the excitation, ionization, and charge-transfer cross sections for the p-He + collision and scaling the results. An impact-parameter coupled-state method with a basis set of up to 51 Sturmian wave functions is used to obtain cross sections at center-of-mass energies ranging from 20 to 600 keV. Along with Stark, Auger, radiative, and stopping rates these cross sections are used to calculate the probability of stripping a muon from αμ by numerically solving a set of coupled differential equations that describe the kinetics of αμ as it travels through a mixture of D 2 and T 2 . An effort has been made to minimize the uncertainty in the value of the stripping probability resulting in error bars of 9% and 11% at densities of 1.2 and 0.05 times liquid-hydrogen density, respectively. X-ray yields belonging to K and L series transitions among αμ states have also been computed. The present results are compared with recent theoretical and experimental data

Electron-excited molecule interactions

International Nuclear Information System (INIS)

Christophorou, L.G.; Tennessee Univ., Knoxville, TN

1991-01-01

In this paper the limited but significant knowledge to date on electron scattering from vibrationally/rotationally excited molecules and electron scattering from and electron impact ionization of electronically excited molecules is briefly summarized and discussed. The profound effects of the internal energy content of a molecule on its electron attachment properties are highlighted focusing in particular on electron attachment to vibrationally/rotationally and to electronically excited molecules. The limited knowledge to date on electron-excited molecule interactions clearly shows that the cross sections for certain electron-molecule collision processes can be very different from those involving ground state molecules. For example, optically enhanced electron attachment studies have shown that electron attachment to electronically excited molecules can occur with cross sections 10 6 to 10 7 times larger compared to ground state molecules. The study of electron-excited molecule interactions offers many experimental and theoretical challenges and opportunities and is both of fundamental and technological significance. 54 refs., 15 figs

Is there hope for fusion?

International Nuclear Information System (INIS)

Fowler, T.K.

1990-01-01

From the outset in the 1950's, fusion research has been motivated by environmental concerns as well as long-term fuel supply issues. Compared to fossil fuels both fusion and fission would produce essentially zero emissions to the atmosphere. Compared to fission, fusion reactors should offer high demonstrability of public protection from accidents and a substantial amelioration of the radioactive waste problem. Fusion still requires lengthy development, the earliest commercial deployment being likely to occur around 2025--2050. However, steady scientific progress is being made and there is a wide consensus that it is time to plan large-scale engineering development. A major international effort, called the International Thermonuclear Experimental Reactor (ITER), is being carried out under IAEA auspices to design the world's first fusion engineering test reactor, which could be constructed in the 1990's. 4 figs., 3 tabs

Fusion Power measurement at ITER

Energy Technology Data Exchange (ETDEWEB)

Bertalot, L.; Barnsley, R.; Krasilnikov, V.; Stott, P.; Suarez, A.; Vayakis, G.; Walsh, M. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France)

2015-07-01

Nuclear fusion research aims to provide energy for the future in a sustainable way and the ITER project scope is to demonstrate the feasibility of nuclear fusion energy. ITER is a nuclear experimental reactor based on a large scale fusion plasma (tokamak type) device generating Deuterium - Tritium (DT) fusion reactions with emission of 14 MeV neutrons producing up to 700 MW fusion power. The measurement of fusion power, i.e. total neutron emissivity, will play an important role for achieving ITER goals, in particular the fusion gain factor Q related to the reactor performance. Particular attention is given also to the development of the neutron calibration strategy whose main scope is to achieve the required accuracy of 10% for the measurement of fusion power. Neutron Flux Monitors located in diagnostic ports and inside the vacuum vessel will measure ITER total neutron emissivity, expected to range from 1014 n/s in Deuterium - Deuterium (DD) plasmas up to almost 10{sup 21} n/s in DT plasmas. The neutron detection systems as well all other ITER diagnostics have to withstand high nuclear radiation and electromagnetic fields as well ultrahigh vacuum and thermal loads. (authors)

Remote control of a fusion facility

Energy Technology Data Exchange (ETDEWEB)

Schissel, D.P. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States)], E-mail: schissel@fusion.gat.com; Abla, G.; Humphreys, D.A.; Penaflor, B.G.; Sammuli, B.S.; Walker, M.L. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States)

2009-06-15

Magnetic fusion experiments keep growing in size and complexity resulting in a concurrent growth in collaboration between experimental sites and laboratories worldwide. This scientific collaboration activity is strong at existing experimental sites, is a major element of machines just coming on line, and is also a thrust of experiments that will come on line in the next decade. Computer science research into enhancing the ability to scientifically participate in a fusion experiment remotely has been growing in size in an attempt to better address the needs of fusion scientists worldwide. The natural progression of this research is to examine how to move from remote scientific participation to remote hardware control. This paper examines the challenges associated with remote experimental device control and proposes a solution based on a semantic approach that defines a Gatekeeper software system that will be the only channel of interaction for incoming requests to the experimental site. The role of the Gatekeeper is to validate the identification and access privilege of the requestor and to ensure the validity of the proposed request. The Gatekeeper will be a modular system, transparent to end-users, and allow a high volume of activity.

Remote control of a fusion facility

International Nuclear Information System (INIS)

Schissel, D.P.; Abla, G.; Humphreys, D.A.; Penaflor, B.G.; Sammuli, B.S.; Walker, M.L.

2009-01-01

Magnetic fusion experiments keep growing in size and complexity resulting in a concurrent growth in collaboration between experimental sites and laboratories worldwide. This scientific collaboration activity is strong at existing experimental sites, is a major element of machines just coming on line, and is also a thrust of experiments that will come on line in the next decade. Computer science research into enhancing the ability to scientifically participate in a fusion experiment remotely has been growing in size in an attempt to better address the needs of fusion scientists worldwide. The natural progression of this research is to examine how to move from remote scientific participation to remote hardware control. This paper examines the challenges associated with remote experimental device control and proposes a solution based on a semantic approach that defines a Gatekeeper software system that will be the only channel of interaction for incoming requests to the experimental site. The role of the Gatekeeper is to validate the identification and access privilege of the requestor and to ensure the validity of the proposed request. The Gatekeeper will be a modular system, transparent to end-users, and allow a high volume of activity.

(Fusion energy research)

Energy Technology Data Exchange (ETDEWEB)

Phillips, C.A. (ed.)

1988-01-01

This report discusses the following topics: principal parameters achieved in experimental devices (FY88); tokamak fusion test reactor; Princeton beta Experiment-Modification; S-1 Spheromak; current drive experiment; x-ray laser studies; spacecraft glow experiment; plasma deposition and etching of thin films; theoretical plasma; tokamak modeling; compact ignition tokamak; international thermonuclear experimental reactor; Engineering Department; Project Planning and Safety Office; quality assurance and reliability; and technology transfer.

[Fusion energy research

International Nuclear Information System (INIS)

Phillips, C.A.

1988-01-01

This report discusses the following topics: principal parameters achieved in experimental devices (FY88); tokamak fusion test reactor; Princeton beta Experiment-Modification; S-1 Spheromak; current drive experiment; x-ray laser studies; spacecraft glow experiment; plasma deposition and etching of thin films; theoretical plasma; tokamak modeling; compact ignition tokamak; international thermonuclear experimental reactor; Engineering Department; Project Planning and Safety Office; quality assurance and reliability; and technology transfer

Controlling flexible rotor vibrations using parametric excitation

Energy Technology Data Exchange (ETDEWEB)

Atepor, L, E-mail: katepor@yahoo.co [Department of Mechanical Engineering, University of Glasgow, G12 8QQ (United Kingdom)

2009-08-01

This paper presents both theoretical and experimental studies of an active vibration controller for vibration in a flexible rotor system. The paper shows that the vibration amplitude can be modified by introducing an axial parametric excitation. The perturbation method of multiple scales is used to solve the equations of motion. The steady-state responses, with and without the parametric excitation terms, is investigated. An experimental test machine uses a piezoelectric exciter mounted on the end of the shaft. The results show a reduction in the rotor response amplitude under principal parametric resonance, and some good correlation between theory and experiment.

Characterization of weakly excited final states by shakedown spectroscopy of laser-excited potassium

International Nuclear Information System (INIS)

Schulz, J.; Heinaesmaeki, S.; Aksela, S.; Aksela, H.; Sankari, R.; Rander, T.; Lindblad, A.; Bergersen, H.; Oehrwall, G.; Svensson, S.; Kukk, E.

2006-01-01

3p shakedown spectra of laser excited potassium atoms as well as direct 3p photoemission of ground state potassium have been studied. These two excitation schemes lead to the same final states and thereby provide a good basis for a detailed study of the 3p 5 (4s3d) 1 configurations of singly ionized potassium and the photoemission processes leading to these configurations. The comparison of direct photoemission from the ground state and conjugate shakedown spectra from 4p 1/2 laser excited potassium made it possible to experimentally determine the character of final states that are only weakly excited in the direct photoemission but have a much higher relative intensity in the shakedown spectrum. Based on considerations of angular momentum and parity conservation the excitation scheme of the final states can be understood

Electron impact excitation and ionization of laser-excited sodium atoms Na*(7d)

International Nuclear Information System (INIS)

Nienhaus, J.; Dorn, A.; Mehlhorn, W.; Zatsarinny, O.I.

1997-01-01

We have investigated the ejected-electron spectrum following impact excitation and ionization of laser-excited Na * (nl) atoms by 1.5 keV electrons. By means of two-laser excitation 3s → 3p 3/2 → 7d and subsequent cascading transitions about 8% (4%) of the target atoms were in excited states with n > 3 (7d). The experimental ejected-electron spectrum due to the decay of Auger and autoionization states of laser-excited atoms Na * (nl) with n = 4-7 has been fully interpreted by comprehensive calculations of the energies, cross sections and decay probabilities of the corresponding states. The various processes contributing to the ejected-electron spectrum are with decreasing magnitude: 2s ionization leading to 2s2p 6 nl Auger states, 2p → 3s excitation leading to 2p 5 3s( 1 P)nl autoionization states and 2s → 3l' excitation leading to 2s2p 6 3l'( 1 L)nl autoionization states. (Author)

Calibrated Noncontact Exciters for Optical Modal Analysis

Directory of Open Access Journals (Sweden)

Henrik O. Saldner

1996-01-01

Full Text Available Two types of exciters were investigated experimentally One of the exciters uses a small permanent magnet fastened on the object. The force is introduced by the change in the electromagnetic field from a coil via an air gap. The second exciter is an eddy-current electromagnet one. The amplitude of the forces from these exciters are calibrated by using dynamic reciprocity in conjunction with electronic holography. These forces strongly depend upon the distance between the exciter and the object.

Experimental fusion power reactor conceptual design study. Final report. Volume II

International Nuclear Information System (INIS)

Baker, C.C.

1976-12-01

This document is the final report which describes the work carried out by General Atomic Company for the Electric Power Research Institute on a conceptual design study of a fusion experimental power reactor (EPR) and an overall EPR facility. The primary objective of the two-year program was to develop a conceptual design of an EPR that operates at ignition and produces continuous net power. A conceptual design was developed for a Doublet configuration based on indications that a noncircular tokamak offers the best potential of achieving a sufficiently high effective fuel containment to provide a viable reactor concept at reasonable cost. Other objectives included the development of a planning cost estimate and schedule for the plant and the identification of critical R and D programs required to support the physics development and engineering and construction of the EPR. This volume contains the following sections: (1) reactor components, (2) auxiliary systems, (3) operations, (4) facility design, (5) program considerations, and (6) conclusions and recommendations

Characterization of incomplete fusion in the reactions Ar + KCl at 32,40,52 and 74 MeV/u; Caracterisation de la fusion incomplete dans les reactions Ar + KCl a 32,40,52 et 74 Mev/u

Energy Technology Data Exchange (ETDEWEB)

Bisquer, E [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; [Universite Claude Bernard, 69 - Lyon (France)

1996-12-20

Heavy ion collisions at intermediate energies (10 to 100 A.MeV) have been investigated and gave evidence to the persistence of so-called low energy mechanisms such as incomplete fusion. This thesis aims at determining the energy threshold beyond which such a mechanism does not occur any more. First we investigated the so-called conventional incomplete fusion. This mechanism is well known from low energy studies: a thermalized compound nucleus is formed which further de-excites by evaporating particles. Residues will be therefore detected in coincidence with mainly light particles. Ar + KCl at incident energies of 32, 40, 52 and 74 A.MeV has been selected for this analysis. These experiments have been performed using the INDRA multidetector in GANIL (Caen). The detection performance of INDRA allowed to use new analysis methods via global variables. In a first step, global variables have been compared in order to find the one that is the most appropriate to our study. Then incomplete fusion events have been extracted from raw events recorded at incident energies of 32, 40 and 52 A.MeV. It turned out that the contribution of this mechanisms was very weak at 52. A.MeV. It turned out that the contribution of this mechanism was very weak at 52 A.MeV and even zero at 74 A.MeV. We then investigated events in which three fragments were detected which could possibly sign multifragmentation. We did not find instantaneous multifragmentation with any expansion contribution. We also performed BNV simulations in order to compare our experimental results to model predictions, solving in a semi-classical way the Vlasov transport equation. A good agreement has been obtained on the size of the compound nucleus formed. However the excitation energy has not been reproduced, as the code seems to overestimate the energy taken away by preequilibrium particles. Incomplete fusion decreases as a function of energy but is not replaced by instantaneous multifragmentation with any expansion

US-Japan Workshop on atomic-collision data for fusion

International Nuclear Information System (INIS)

Crandall, D.H.; Hafford, P.M.; Itikawa, Y.

1981-04-01

This report, containing abstracts of each of the presentations and discussions, includes: brief talks on the applications of atomic data in tokamaks and in inertial confinement; reviews of the specific atomic collisions projects for fusion in Japan and the United States; discussions of how the data centers operate and manner of exchanging data; brief reviews of the status of electron-ion scattering and ion-atom scattering; discussions of criteria to be used in evaluating and selecting both experimental and theoretical data in these two areas; comparisons of data selected for each of six specific collision reactions which were evaluated by both groups prior to the workshop; brief reviews of activities in the related areas of atomic structure and plasma wall interactions; and a decision to pursue a joint or collaborative compilation of recommended cross sections for oxygen ions for electron impact excitation and electron capture from atomic hydrogen

Catalogue of nuclear fusion codes - 1976

International Nuclear Information System (INIS)

1976-10-01

A catalogue is presented of the computer codes in nuclear fusion research developed by JAERI, Division of Thermonuclear Fusion Research and Division of Large Tokamak Development in particular. It contains a total of about 100 codes under the categories: Atomic Process, Data Handling, Experimental Data Processing, Engineering, Input and Output, Special Languages and Their Application, Mathematical Programming, Miscellaneous, Numerical Analysis, Nuclear Physics, Plasma Physics and Fusion Research, Plasma Simulation and Numerical Technique, Reactor Design, Solid State Physics, Statistics, and System Program. (auth.)

The European Fusion Energy Research Programme towards the realization of a fusion demonstration reactor

International Nuclear Information System (INIS)

Gasparotto, M.; Laesser, R.

2006-01-01

Since its inception, the European Fusion Programme has been orientated towards the establishment of the knowledge base needed for the definition of a reactor to be used for power production. Its ultimate goal is then to demonstrate the scientific and the technological feasibility of fusion power while incorporating the assessment of the safety, environmental, social and economic features of this type of energy source. At present, the JET device, the largest tokamak in the world, and the other medium-sized experimental machines are contributing essentially to the basic scientific phase of this development path. Their successful operation greatly contributed to support the design basis of ITER, the next step in fusion, which will aim to demonstrate the scientific and technical feasibility of fusion power production by achieving extended D-T burning plasma operation. Following ITER, the conception and construction of the DEMO device is planned. DEMO will be a demonstration power plant which will be the first fusion device to generate a significant amount of electrical power from fusion. This paper describes the status of fusion research and the European strategy for achievement of the ultimate goal of construction of a prototype reactor. (author)

Fiber pigtailed thin wall capillary coupler for excitation of microsphere WGM resonator.

Science.gov (United States)

Wang, Hanzheng; Lan, Xinwei; Huang, Jie; Yuan, Lei; Kim, Cheol-Woon; Xiao, Hai

2013-07-01

In this paper, we demonstrate a fiber pigtailed thin wall capillary coupler for excitation of Whispering Gallery Modes (WGMs) of microsphere resonators. The coupler is made by fusion-splicing an optical fiber with a capillary tube and consequently etching the capillary wall to a thickness of a few microns. Light is coupled through the peripheral contact between inserted microsphere and the etched capillary wall. The coupling efficiency as a function of the wall thickness was studied experimentally. WGM resonance with a Q-factor of 1.14 × 10(4) was observed using a borosilicate glass microsphere with a diameter of 71 μm. The coupler operates in the reflection mode and provides a robust mechanical support to the microsphere resonator. It is expected that the new coupler may find broad applications in sensors, optical filters and lasers.

Fusion energy research for ITER and beyond

International Nuclear Information System (INIS)

Romanelli, Francesco; Laxaaback, Martin

2011-01-01

The achievement in the last two decades of controlled fusion in the laboratory environment is opening the way to the realization of fusion as a source of sustainable, safe and environmentally responsible energy. The next step towards this goal is the construction of the International Thermonuclear Experimental Reactor (ITER), which aims to demonstrate net fusion energy production on the reactor scale. This paper reviews the current status of magnetic confinement fusion research in view of the ITER project and provides an overview of the main remaining challenges on the way towards the realization of commercial fusion energy production in the second half of this century. (orig.)

Experimental study of angular neutron flux spectra on a slab surface to assess nuclear data and calculational methods for a fusion reactor design

International Nuclear Information System (INIS)

Oyama, Yukio

1988-06-01

This paper presents an experimental approach to interpret the results of integral experiments for fusion neutronics research. The measurement is described of the angular neutron flux on a restricted area of slab assemblies with D-T neutron bombardment by using the time-of-flight (TOF) method with an NE213 neutron detector over an energy range from 0.05 to 15 MeV. A two bias scheme was developed to obtain an accurate detection efficiency over a wide energy range. The detector-collimator response function was introduced to define the restricted surface area and to determine the effective measured area. A series of measurements of the angular neutron flux on slabs of fusion blanket materials, i.e., Be, C, and Li 2 O, as functions of neutron leaking angle and slab thickness have been performed to examine neutron transport characteristics in bulk materials. The calculational analyses of the experimental results have been also carried out by using Monte Carlo neutron transport codes, i.e., MORSE-DD and MCNP. The existing nuclear data files, i.e., JENDL-3PR1, -3PR2, ENDF/B-IV and -V were tested by comparing with the experimental results. From the comparisons, the data on C and 7 Li in the present files are fairly sufficient. Those on beryllium, however, is insufficient for the estimation of high threshold reactions such as tritium production in a fusion reactor blanket design. It is also found that the total and elastic cross sections are more important for accurate predictions of neutronic parameters at deep position. The comparisons between the measured and calculated results provide information to understand the results of the previous integral experiments for confirmation of accuracy of fusion reactor designs. (author)

Cold fusion catalyzed by muons and electrons

International Nuclear Information System (INIS)

Kulsrud, R.M.

1990-10-01

Two alternative methods have been suggested to produce fusion power at low temperature. The first, muon catalyzed fusion or MCF, uses muons to spontaneously catalyze fusion through the muon mesomolecule formation. Unfortunately, this method fails to generate enough fusion energy to supply the muons, by a factor of about ten. The physics of MCF is discussed, and a possible approach to increasing the number of MCF fusions generated by each muon is mentioned. The second method, which has become known as ''Cold Fusion,'' involves catalysis by electrons in electrolytic cells. The physics of this process, if it exists, is more mysterious than MCF. However, it now appears to be an artifact, the claims for its reality resting largely on experimental errors occurring in rather delicate experiments. However, a very low level of such fusion claimed by Jones may be real. Experiments in cold fusion will also be discussed

Experimental study of electron temperature gradient influence on impurity turbulent transport in fusion plasmas

International Nuclear Information System (INIS)

Villegas, D.

2010-01-01

Understanding impurity transport is a key to an optimal regime for a future fusion device. In this thesis, the theoretical and experimental influence of the electron temperature gradient R/L Te on heavy impurity transport is analyzed both in Tore Supra and ASDEX Upgrade. The electron temperature profile is modified locally by heating the plasma with little ECRH power deposited at two different radii. Experimental results have been obtained with the impurity transport code (ITC) which has been completed with a genetic algorithm allowing to determine the transport coefficient profiles with more accuracy. Transport coefficient profiles obtained by a quasilinear gyrokinetic code named QuaLiKiz are consistent with the experimental ones despite experimental uncertainties on gradients. In the core dominated by electron modes, the lower R/L Te the lower the nickel diffusion coefficient. The latter tends linearly to the neoclassical level when the instability threshold is approached. The experimental threshold is in agreement with the one computed by QuaLiKiz. Further out, where the plasma is dominated by ITG, which are independent of R/L Te , both experimental and simulated results show no modification in the diffusion coefficient profile. Furthermore, the convection velocity profile is not modified. This is attributed to a very small contribution of the thermodiffusion (1/Z dependence) in the total convection. On ASDEX, the preliminary results, very different from the Tore Supra ones, show a internal transport barrier for impurities located at the same radius as the strong ECRH power deposit. (author) [fr

Study of incomplete fusion reaction dynamics in 13C +165 Ho system and its dependence on various entrance channel parameters

Science.gov (United States)

Tali, Suhail A.; Kumar, Harish; Ansari, M. Afzal; Ali, Asif; Singh, D.; Ali, Rahbar; Giri, Pankaj K.; Linda, Sneha B.; Parashari, Siddharth; Kumar, R.; Singh, R. P.; Muralithar, S.

2018-02-01

The excitation functions for the evaporation residues populated in the interaction of 13C +165 Ho system have been measured at projectile energies ≈ 4-7 MeV/nucleon. Stacked foil activation technique followed by off-line γ-ray spectroscopy have been employed in the present work. The experimentally measured cross-sections are analyzed in the frame work of statistical model code PACE4, which takes into account only the complete fusion reaction cross-sections. The evaporation residues populated via xn and pxn channels were found to be in good agreement with the PACE4 predictions, while a significant enhancement in the measured cross-sections over PACE4 predictions is observed in case of α-emitting channels, which may be attributed to the incomplete fusion process. For the better understanding of incomplete fusion dynamics, the incomplete fusion fraction has also been deduced and its sensitivity with various entrance channel parameters like: projectile energy, mass-asymmetry, projectile structure in terms of Qα-value and Coulomb effect has been studied in the present work. The incomplete fusion fraction is found to increase with increasing the projectile energy and a strong projectile structure dependent mass-asymmetry systematic is also observed. The incomplete fusion fraction is also found to be small for more negative Qα-value projectile (13C) induced reactions as compared to less negative Qα-value projectiles (12C, 16O and 20Ne) induced reactions with the same target nucleus 165Ho. An interesting trend is obtained on further investigation of incomplete fusion dependence on Coulomb effect (ZPZT).

Dirac R -matrix calculations for the electron-impact excitation of neutral tungsten providing noninvasive diagnostics for magnetic confinement fusion

Science.gov (United States)

Smyth, R. T.; Ballance, C. P.; Ramsbottom, C. A.; Johnson, C. A.; Ennis, D. A.; Loch, S. D.

2018-05-01

Neutral tungsten is the primary candidate as a wall material in the divertor region of the International Thermonuclear Experimental Reactor (ITER). The efficient operation of ITER depends heavily on precise atomic physics calculations for the determination of reliable erosion diagnostics, helping to characterize the influx of tungsten impurities into the core plasma. The following paper presents detailed calculations of the atomic structure of neutral tungsten using the multiconfigurational Dirac-Fock method, drawing comparisons with experimental measurements where available, and includes a critical assessment of existing atomic structure data. We investigate the electron-impact excitation of neutral tungsten using the Dirac R -matrix method, and by employing collisional-radiative models, we benchmark our results with recent Compact Toroidal Hybrid measurements. The resulting comparisons highlight alternative diagnostic lines to the widely used 400.88-nm line.

Propagation and excitation of graphene plasmon polaritons

DEFF Research Database (Denmark)

Zhu, Xiaolong; Yan, Wei; Jeppesen, Claus

2013-01-01

We theoretically investigate the propagation of graphene plasmon polaritons in graphene nanoribbon waveguides and experimentally observe the excitation of the graphene plasmon polaritons in a continuous graphene monolayer. We show that graphene nanoribbon bends do not induce any additional loss...... and nanofocusing occurs in a tapered graphene nanoriboon, and we experimentally demonstrate the excitation of graphene plasmon polaritonss in a continuous graphene monolayer assisted by a two-dimensional subwavelength silicon grating....

Dynamical limitations to heavy ion fusion

International Nuclear Information System (INIS)

Back, B.B.

1983-01-01

Dynamical limitations to heavy ion fusion reaction are considered. The experimental signatures and the importance of a quasi-fission process are examined. The anaular distributions of fission fragments for the 32 S+ 208 Pb and 16 O+ 238 U systems are presented. It is shown that the observations of quasi-fission for even rather ''light'' heavy ions poeess severe limitations on the fusion process. This result may consequently be responsible for the lack of success of the search for super heavy elements in heavy ion fusion reactions

Fusion the energy of the universe

CERN Document Server

McCracken, Garry

2012-01-01

Fusion: The Energy of the Universe, 2e is an essential reference providing basic principles of fusion energy from its history to the issues and realities progressing from the present day energy crisis. The book provides detailed developments and applications for researchers entering the field of fusion energy research. This second edition includes the latest results from the National Ignition Facility at the Lawrence Radiation Laboratory at Livermore, CA, and the progress on the International Thermonuclear Experimental Reactor (ITER) tokamak programme at Caderache, France.

Two-photon excitation of argon

International Nuclear Information System (INIS)

Pindzola, P.S.; Payne, M.C.

1982-01-01

The authors calculate two photon excitation parameters for various excited states of argon assuming the absorption of near resonance broad-bandwidth laser radiation. Results are given for the case of two photons absorbed for the same laser beam as well as the case of absorbing photons of different frequency from each of two laser beams. The authors use multiconfiguration Hartree-Fock wave functions to evaluate the second-order sums over matrix elements. Various experimental laser schemes are suggested for the efficient excitation and subsequent ionization of argon

A dynamical theory of incomplete fusion reactions: The breakup-fusion reaction approach

International Nuclear Information System (INIS)

Udagawa, T.

1984-01-01

A dynamical theory of partial fusion reactions is presented, which may fill the gap between direct and compound nuclear reaction theories. With the new theory one can calculate partial fusion taking place in three-body (and many more) channels reached via direct reactions, e.g., breakup and knockout reactions. The authors present first the results for the cross section for such reactions, taking as an example breakup followed by fusion. They then discuss a physical picture which emerges from their theory, namely that the partial fusion reactions, particularly of the massive-transfer type, take place in a so-called deep peripheral region. It is also shown that the deep peripheral character of such processes diminishes as the mass of the fused system decreases, so that the reactions essentially evolve to the usual peripheral character. Finally, comparisons are made of results of numerical calculations with experimental data, taking as an example the /sup 159/Tb(/sup 14/N,α) reaction with E/sub lab/ = 95 MeV

Physics of laser fusion. Volume II. Diagnostics of experiments on laser fusion targets at LLNL

Energy Technology Data Exchange (ETDEWEB)

Ahlstrom, H.G.

1982-01-01

These notes present the experimental basis and status for laser fusion as developed at LLNL. There are two other volumes in this series: Vol. I, by C.E. Max, presents the theoretical laser-plasma interaction physics; Vol. III, by J.F. Holzrichter et al., presents the theory and design of high-power pulsed lasers. A fourth volume will present the theoretical implosion physics. The notes consist of six sections. The first, an introductory section, provides some of the history of inertial fusion and a simple explanation of the concepts involved. The second section presents an extensive discussion of diagnostic instrumentation used in the LLNL Laser Fusion Program. The third section is a presentation of laser facilities and capabilities at LLNL. The purpose here is to define capability, not to derive how it was obtained. The fourth and fifth sections present the experimental data on laser-plasma interaction and implosion physics. The last chapter is a short projection of the future.

Physics of laser fusion. Volume II. Diagnostics of experiments on laser fusion targets at LLNL

International Nuclear Information System (INIS)

Ahlstrom, H.G.

1982-01-01

These notes present the experimental basis and status for laser fusion as developed at LLNL. There are two other volumes in this series: Vol. I, by C.E. Max, presents the theoretical laser-plasma interaction physics; Vol. III, by J.F. Holzrichter et al., presents the theory and design of high-power pulsed lasers. A fourth volume will present the theoretical implosion physics. The notes consist of six sections. The first, an introductory section, provides some of the history of inertial fusion and a simple explanation of the concepts involved. The second section presents an extensive discussion of diagnostic instrumentation used in the LLNL Laser Fusion Program. The third section is a presentation of laser facilities and capabilities at LLNL. The purpose here is to define capability, not to derive how it was obtained. The fourth and fifth sections present the experimental data on laser-plasma interaction and implosion physics. The last chapter is a short projection of the future

Academic Training: New Trends in Fusion Research

CERN Multimedia

Françoise Benz

2004-01-01

11, 12 and 13 October 2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 11 October from 11.00 to 12.00 hrs, 12 and 13 October from 10.00 to 12.00 hrs - 11 and 12 October in the Main Auditorium, bldg. 500, 13 October in the TH Amphitheatre New Trends in Fusion Research A. FASOLI / EPFL, Lausanne, CH The efforts of the international fusion community aim at demonstrating the scientific feasibility of thermonuclear fusion energy power plants. Understanding the behavior of burning plasmas, i.e. plasmas with strong self-heating, represents a primary scientific challenge for fusion research and a new science frontier. Although integrated studies will only be possible, in new, dedicated experimental facilities, such as the International Tokamak Experimental Reactor (ITER), present devices can address specific issues in regimes relevant to burning plasmas. Among these are an improvement of plasma performance via a reduction of the energy and particle transport, an optimization of the path to ignition or to su...

Academic Training: New Trends in Fusion Research

CERN Multimedia

Françoise Benz

2004-01-01

11, 12 and 13 October 2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 11 October from 11.00 to 12.00 hrs, 12 and 13 October from 10.00 to 12.00 hrs - 11 and 12 October in the Main Auditorium, bldg. 500, 13 October in the Theory Conference Room, bldg. 4 New Trends in Fusion Research A. FASOLI / EPFL, Lausanne, CH The efforts of the international fusion community aim at demonstrating the scientific feasibility of thermonuclear fusion energy power plants. Understanding the behavior of burning plasmas, i.e. plasmas with strong self-heating, represents a primary scientific challenge for fusion research and a new science frontier. Although integrated studies will only be possible, in new, dedicated experimental facilities, such as the International Tokamak Experimental Reactor (ITER), present devices can address specific issues in regimes relevant to burning plasmas. Among these are an improvement of plasma performance via a reduction of the energy and particle transport, an optimization of the path to i...

Laser Fusion: status, future, and tritium control

International Nuclear Information System (INIS)

Coyle, P.E.

1978-11-01

At Livermore the 10 kJ, 20 to 30 TW Shiva facility is now operational and producing regular new fusion results. Design work has begun on a 200 to 300 TW laser designed to carry the program through the first breakeven demonstration experiments in the mid-1980's. Confidence in reaching this goal is based on the significant progress we have made in state-of-the-art, high-power Nd:glass laser technology, in experimental laser fusion and laser plasma interaction physics, and in theoretical and analytical computer codes which reliably model and predict experimental results. For all of these experiments, a variety of fusion targets are being fabricated in the laboratory, and the control and handling of tritium is now a regular and routine part of ongoing inertial fusion experiments. Target design with gains of about 1000 have been studied and the means to mass produce such pellets at low cost are also being developed

Survey of the laser-solenoid fusion reactor

International Nuclear Information System (INIS)

Amherd, N.A.

1975-09-01

This report surveys the prospects for a laser-solenoid fusion reactor. A sample reactor and scaling laws are used to describe the concept's characteristics. Experimental results are reviewed, and the laser and magnet technologies that undergird the laser-solenoid concept are analyzed. Finally, a systems analysis of fusion power reactors is given, including a discussion of direct conversion and fusion-fission effects, to ascertain the system attributes of the laser-solenoid configuration

EDITORIAL: Plasma Surface Interactions for Fusion

Science.gov (United States)

2006-05-01

Because plasma-boundary physics encompasses some of the most important unresolved issues for both the International Thermonuclear Experimental Reactor (ITER) project and future fusion power reactors, there is a strong interest in the fusion community for better understanding and characterization of plasma wall interactions. Chemical and physical sputtering cause the erosion of the limiters/divertor plates and vacuum vessel walls (made of C, Be and W, for example) and degrade fusion performance by diluting the fusion fuel and excessively cooling the core, while carbon redeposition could produce long-term in-vessel tritium retention, degrading the superior thermo-mechanical properties of the carbon materials. Mixed plasma-facing materials are proposed, requiring optimization for different power and particle flux characteristics. Knowledge of material properties as well as characteristics of the plasma material interaction are prerequisites for such optimizations. Computational power will soon reach hundreds of teraflops, so that theoretical and plasma science expertise can be matched with new experimental capabilities in order to mount a strong response to these challenges. To begin to address such questions, a Workshop on New Directions for Advanced Computer Simulations and Experiments in Fusion-Related Plasma Surface Interactions for Fusion (PSIF) was held at the Oak Ridge National Laboratory from 21 to 23 March, 2005. The purpose of the workshop was to bring together researchers in fusion related plasma wall interactions in order to address these topics and to identify the most needed and promising directions for study, to exchange opinions on the present depth of knowledge of surface properties for the main fusion-related materials, e.g., C, Be and W, especially for sputtering, reflection, and deuterium (tritium) retention properties. The goal was to suggest the most important next steps needed for such basic computational and experimental work to be facilitated

Fusion reactor materials

Energy Technology Data Exchange (ETDEWEB)

none,

1989-01-01

This paper discuses the following topics on fusion reactor materials: irradiation, facilities, test matrices, and experimental methods; dosimetry, damage parameters, and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; radiation effects; development of structural alloys; solid breeding materials; and ceramics.

Fusion reactor materials

International Nuclear Information System (INIS)

1989-01-01

This paper discuses the following topics on fusion reactor materials: irradiation, facilities, test matrices, and experimental methods; dosimetry, damage parameters, and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; radiation effects; development of structural alloys; solid breeding materials; and ceramics

Fusion Technology for ITER, the ITER Project. Further Development Towards a DEMO Fusion Power Plant (3/4)

CERN Multimedia

CERN. Geneva

2011-01-01

This is the second half of a lecture series on fusion and will concentrate on fusion technology. The early phase of fusion development was concentrated on physics. However, during the 1980s it was realized that if one wanted to enter the area of fusion reactor plasmas, even in an experimental machine, a significant advance in fusion technologies would be needed. After several conceptual studies of reactor class fusion devices in the 1980s the engineering design phase of ITER started in earnest during the 1990s. The design team was in the beginning confronted with many challenges in the fusion technology area as well as in physics for which no readily available solution existed and in a few cases it was thought that solutions may be impossible to find. However, after the initial 3 years of intensive design and R&D work in an international framework utilizing basic fusion technology R&D from the previous decade it became clear that for all problems a conceptual solution could be found and further devel...

Nuclear Fusion Fuel Cycle Research Perspectives

International Nuclear Information System (INIS)

Chung, Hongsuk; Koo, Daeseo; Park, Jongcheol; Kim, Yeanjin; Yun, Sei-Hun

2015-01-01

As a part of the International Thermonuclear Experimental Reactor (ITER) Project, we at the Korea Atomic Energy Research Institute (KAERI) and our National Fusion Research Institute (NFRI) colleagues are investigating nuclear fusion fuel cycle hardware including a nuclear fusion fuel Storage and Delivery System (SDS). To have a better knowledge of the nuclear fusion fuel cycle, we present our research efforts not only on SDS but also on the Fuel Supply System (FS), Tokamak Exhaust Processing System (TEP), Isotope Separation System (ISS), and Detritiation System (DS). To have better knowledge of the nuclear fusion fuel cycle, we presented our research efforts not only on SDS but also on the Fuel Supply System (FS), Tokamak Exhaust Processing System (TEP), Isotope Separation System (ISS), and Detritiation System (DS). Our efforts to enhance the tritium confinement will be continued for the development of cleaner nuclear fusion power plants

The fusion rate in the transmission resonance model

International Nuclear Information System (INIS)

Jaendel, M.

1992-01-01

Resonant transmission of deuterons through a chain of target deuterons in a metal matrix has been suggested as an explanation for the cold fusion phenomena. In this paper the fusion rate in such transmission resonance models is estimated, and the basic physical constraints are discussed. The dominating contribution to the fusion yield is found to come from metastable states. The fusion rate is well described by the Wentzel-Kramer-Brillouin approximation and appears to be much too small to explain the experimental anomalies

Oscillations in the fusion of the Si + Si systems; Oscilaciones en la fusion de sistemas de Si + Si

Energy Technology Data Exchange (ETDEWEB)

Aguilera R, E F; Kolata, J J; DeYoung, P A; Vega, J J [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

1986-02-15

Excitation functions for the yields of all the residual nuclei from the {sup 28} Si + {sup 28,30} and {sup 30} Si + {sup 30} Si reactions have been measured via the {gamma}-ray technique for center of mass energies in the region within one and two times the Coulomb barrier.Thirteen elements were identified for the first reaction and ten for the other two. While no structure is shown by the data for the {sup 28} + {sup 28} Si reaction, we have found evidence for intermediate width structure in the 2{alpha} and the {alpha}pn channels in {sup 28} Si + {sup 30} Si and for broad structure in the total fusion cross sections for {sup 30} Si + {sup 30} Si. Calculations using a barrier penetration model with one free parameter reproduce the experimental results quite well. Evaporation model calculations indicate that the individual structure of the nuclei involved in the respective decay chains might have an important influence upon the deexcitation process at the energies relevant to our experiments. (Author)

International bulletin on atomic and molecular data for fusion. No. 17

International Nuclear Information System (INIS)

Katsonis, K.; Langley, R.A.

1981-11-01

This bulletin deals with atomic and molecular data for fusion. A bibliography for the most recent data presented in the document is provided. Work in progress is briefly reported: Electron ionization cross sections for light elements, single electron capture by highly charged ions colliding with hydrogen, inconel 626 surface exfoliation, cavities in nickel induced by helium ion irradiation, electron impact excitation of hydrogenic ions. The bulletin contains a list of references for the publications on controlled fusion and plasma physics for 1980 and 1981

Reconnaissance blind multi-chess: an experimentation platform for ISR sensor fusion and resource management

Science.gov (United States)

Newman, Andrew J.; Richardson, Casey L.; Kain, Sean M.; Stankiewicz, Paul G.; Guseman, Paul R.; Schreurs, Blake A.; Dunne, Jeffrey A.

2016-05-01

This paper introduces the game of reconnaissance blind multi-chess (RBMC) as a paradigm and test bed for understanding and experimenting with autonomous decision making under uncertainty and in particular managing a network of heterogeneous Intelligence, Surveillance and Reconnaissance (ISR) sensors to maintain situational awareness informing tactical and strategic decision making. The intent is for RBMC to serve as a common reference or challenge problem in fusion and resource management of heterogeneous sensor ensembles across diverse mission areas. We have defined a basic rule set and a framework for creating more complex versions, developed a web-based software realization to serve as an experimentation platform, and developed some initial machine intelligence approaches to playing it.

Relaxation of helium levels excited by heavy ion impact: III.- Orientation by anisotropic relaxation of excited atoms in previously aligned states

International Nuclear Information System (INIS)

Chamoun, E.; Lombardi, M.; Carre, M.; Gaillard, M.L.

1977-01-01

In the last paper of this series devoted to relaxation phenomena in a low pressure cell of helium excited by an accelerated ion beam, experimental evidence is given for a new mechanism of transfer between alignment and orientation through anisotropic relaxation of initially aligned excited states. The theory predicting this effect is briefly outlined and then description is given of the exact experimental conditions to detect the circularly polarized component of the light emitted by the target excited in the 4 1 D level of He I by Na + impact [fr

Experimental and theoretical dipole moments of purines in their ground and lowest excited singlet states

Science.gov (United States)

Aaron, Jean-Jacques; Diabou Gaye, Mame; Párkányi, Cyril; Cho, Nam Sook; Von Szentpály, László

1987-01-01

The ground-state dipole moments of seven biologically important purines (purine, 6-chloropurine, 6-mercaptopurine, hypoxanthine, theobromine, theophylline and caffeine) were determined at 25°C in acetic acid (all the above compounds with the exception of purine) and in ethyl acetate (purine, theophylline and caffeine). Because of its low solubility, it was not possible to measure the dipole moment of uric acid. The first excited singlet-state dipole moments were obtained on the basis of the Bakhshiev and Chamma—Viallet equations using the variation of the Stokes shift with the solvent dielectric constant-refractive index term. The theoretical dipole moments for all the purines listed above and including uric acid were calculated by combining the use of the PPP (π-LCI-SCF-MO) method for the π-contribution to the overall dipole moment with the σ-contribution obtained as a vector sum of the σbond moments and group moments. The experimental and theoretical values were compared with the data available in the literature for some of the purines under study. For several purines, the calculations were carried out for different tautomeric forms. Excited singlet-state dipole moments are smaller than the ground-state values by 0.8 to 2.2 Debye units for all purines under study with the exception of 6-chloropurine. The effects of the structure upon the ground- and excited-state dipole moments of the purines are discussed.

Helical-type device and laser fusion. Rivals for tokamak-type device at n-fusion development in Japan

International Nuclear Information System (INIS)

Anon.

1994-01-01

Under the current policy on the research and development of nuclear fusion in Japan, as enunciated by the Atomic Energy Commission of Japan, the type of a prototype fusion reactor will be chosen after 2020 from tokamak, helical or some other type including the inertial confinement fusion using lasers. A prototype fusion reactor is the next step following the tokamak type International Thermonuclear Experimental Reactor (ITER). With the prototype reactor, the feasibility as a power plant will be examined. At present the main research and development of nuclear fusion in Japan are on tokamak type, which have been promoted by Japan Atomic Energy Research Institute (JAERI). As for the other types of nuclear fusion, researches have been carried out on the helical type in Kyoto University and National Institute for Fusion Science (NIFS), the mirror type in Tsukuba University, the tokamak type using superconductive coils in Kyushu University, and the laser fusion in Osaka University. The features and the present state of research and development of the Large Helical Device and the laser fusion which is one step away from the break-even condition are reported. (K.I.)

Additional gleaning of fusion energy development

International Nuclear Information System (INIS)

Yamamoto, Kenzo; Koizumi, Koichi

2002-09-01

This report summarizes the major topics in the history of fusion energy development in Japan from its dawn to the tokamak fusion experimental reactor, ITER. The domestic circumstances and situation in foreign countries in those days, and the details of each decision and discussion, are described. Since my previous writing, 'Forty years for Nuclear Fusion Energy Development - Big Science in Japan (1997, ERC Press. Co. Ltd.)', was a book which briefly summarize a large quantity of documents on the history, there are many points, which require additional detail explanation. This time, I selected and extracted major topics in the fusion research history, and added additional descriptions and my comments so as to supplement my previous writing. (author)

Fusion research at ORNL

International Nuclear Information System (INIS)

1982-03-01

The ORNL Fusion Program includes the experimental and theoretical study of two different classes of magnetic confinement schemes - systems with helical magnetic fields, such as the tokamak and stellarator, and the ELMO Bumpy Torus (EBT) class of toroidally linked mirror systems; the development of technologies, including superconducting magnets, neutral atomic beam and radio frequency (rf) heating systems, fueling systems, materials, and diagnostics; the development of databases for atomic physics and radiation effects; the assessment of the environmental impact of magnetic fusion; and the design of advanced demonstration fusion devices. The program involves wide collaboration, both within ORNL and with other institutions. The elements of this program are shown. This document illustrates the program's scope; and aims by reviewing recent progress

A proposed safety assurance method and its application to the fusion experimental reactor

International Nuclear Information System (INIS)

Okazaki, T.; Seki, Y.; Inabe, T.; Aoki, I.

1995-01-01

Importance categorization and hazard identification methods have been proposed for a fusion experimental reactor. A parameter, the system index, is introduced in the categorization method. The relative importance of systems with safety functions can be classified by the largeness of the system index and whether or not the system acts as a boundary for radioactive materials. This categorization can be used as the basic principle in determining structure design assessment, seismic design criteria etc. For the hazard identification the system time energy matrix is proposed, where the time and spatial distributions of hazard energies are used. This approach is formulated more systematically than an ad-hoc identification of hazard events and it is useful to select design basis events which are employed in the assessment of safety designs. (orig.)

Nuclear structure in cold rearrangement processes in fission and fusion

Energy Technology Data Exchange (ETDEWEB)

Armbruster, P.

1998-11-01

In fission and fusion of heavy nuclei large numbers of nucleons are rearranged at a scale of excitation energy very small compared to the binding energy of the nuclei. The energies involved are less than 40 MeV at nuclear temperatures below 1.5 MeV. The shapes of the configurations in the rearrangement of a binary system into a monosystem in fusion, or vice versa in fission, change their elongations by as much as 8 fm, the radius of the monosystem. The dynamics of the reactions macroscopically described by a potential energy surface, inertia parameters, dissipation, and a collision energy is strongly modified by the nuclear structure of the participating nuclei. Experiments showing nuclear structure effects in fusion and fission of the heaviest nuclei are reviewed. The reaction kinematics and the multitude of isotopes involved are investigated by detector techniques and by recoil spectrometers. The advancement of the latter allows to find very small reaction branches in the range of 10{sup -5} to 10{sup -10}. The experiments reveal nuclear structure effects in all stages of the rearrangement processes. These are discussed pointing to analogies in fusion and fission on the microscopic scale, notwithstanding that both processes macroscopically are irreversible. Heavy clusters, as 132Sn, 208Pb, nuclei with closed shell configurations N=82,126, Z=50,82 survive in large parts of the nuclear rearrangement. They determine the asymmetry in the mass distribution of low energy fission, and they allow to synthesise superheavy elements, until now up to element 112. Experiments on the cold rearrangement in fission and fusion are presented. Here, in the range of excitation energies below 12 MeV the phenomena are observed most convincingly. (orig.)

Nuclear Fusion prize laudation Nuclear Fusion prize laudation

Science.gov (United States)

Burkart, W.

2011-01-01

Clean energy in abundance will be of critical importance to the pursuit of world peace and development. As part of the IAEA's activities to facilitate the dissemination of fusion related science and technology, the journal Nuclear Fusion is intended to contribute to the realization of such energy from fusion. In 2010, we celebrated the 50th anniversary of the IAEA journal. The excellence of research published in the journal is attested to by its high citation index. The IAEA recognizes excellence by means of an annual prize awarded to the authors of papers judged to have made the greatest impact. On the occasion of the 2010 IAEA Fusion Energy Conference in Daejeon, Republic of Korea at the welcome dinner hosted by the city of Daejeon, we celebrated the achievements of the 2009 and 2010 Nuclear Fusion prize winners. Steve Sabbagh, from the Department of Applied Physics and Applied Mathematics, Columbia University, New York is the winner of the 2009 award for his paper: 'Resistive wall stabilized operation in rotating high beta NSTX plasmas' [1]. This is a landmark paper which reports record parameters of beta in a large spherical torus plasma and presents a thorough investigation of the physics of resistive wall mode (RWM) instability. The paper makes a significant contribution to the critical topic of RWM stabilization. John Rice, from the Plasma Science and Fusion Center, MIT, Cambridge is the winner of the 2010 award for his paper: 'Inter-machine comparison of intrinsic toroidal rotation in tokamaks' [2]. The 2010 award is for a seminal paper that analyzes results across a range of machines in order to develop a universal scaling that can be used to predict intrinsic rotation. This paper has already triggered a wealth of experimental and theoretical work. I congratulate both authors and their colleagues on these exceptional papers. W. Burkart Deputy Director General Department of Nuclear Sciences and Applications International Atomic Energy Agency, Vienna

Quinary excitation method for pulse compression ultrasound measurements.

Science.gov (United States)

Cowell, D M J; Freear, S

2008-04-01

A novel switched excitation method for linear frequency modulated excitation of ultrasonic transducers in pulse compression systems is presented that is simple to realise, yet provides reduced signal sidelobes at the output of the matched filter compared to bipolar pseudo-chirp excitation. Pulse compression signal sidelobes are reduced through the use of simple amplitude tapering at the beginning and end of the excitation duration. Amplitude tapering using switched excitation is realised through the use of intermediate voltage switching levels, half that of the main excitation voltages. In total five excitation voltages are used creating a quinary excitation system. The absence of analogue signal generation and power amplifiers renders the excitation method attractive for applications with requirements such as a high channel count or low cost per channel. A systematic study of switched linear frequency modulated excitation methods with simulated and laboratory based experimental verification is presented for 2.25 MHz non-destructive testing immersion transducers. The signal to sidelobe noise level of compressed waveforms generated using quinary and bipolar pseudo-chirp excitation are investigated for transmission through a 0.5m water and kaolin slurry channel. Quinary linear frequency modulated excitation consistently reduces signal sidelobe power compared to bipolar excitation methods. Experimental results for transmission between two 2.25 MHz transducers separated by a 0.5m channel of water and 5% kaolin suspension shows improvements in signal to sidelobe noise power in the order of 7-8 dB. The reported quinary switched method for linear frequency modulated excitation provides improved performance compared to pseudo-chirp excitation without the need for high performance excitation amplifiers.

Fusion cross sections measurement for 6Li + 159Tb

International Nuclear Information System (INIS)

Pradhan, M.K.; Mukherjee, A.; Kshetri, R.; Roy, Subinit; Basu, P.; Goswami, A.; Saha Sarkar, M.; Ray, M.; Parkar, V.; Santra, S.; Kailas, S.; Palit, R.

2009-01-01

In order to investigate the effect of projectile breakup threshold energy on fusion in mass region around A∼170, we have carried out a systematic investigation of the fusion (both CF and ICF) cross sections for the systems 11 B, 10 B + 159 Tb and 7 Li + 159 Tb at energies near and close to the barrier where 11 B was considered to be a strongly bound nucleus. The nucleus 10 B has a α-separation energy of 4.5 MeV. The measurements show that the extent of suppression of CF cross sections is correlated with the α-separation energies of the projectiles. As a further continuation of this work, we have recently carried out fusion excitation function measurement for the system 6 Li + 159 Tb (Coulomb barrier 27 MeV) at energies near and close to the barrier

Fusion Teaching: Utilizing Course Management Technology to Deliver an Effective Multimodal Pedagogy

Science.gov (United States)

Childs, Bradley D.; Cochran, Howard H.; Velikova, Marieta

2013-01-01

Fusion teaching merges several pedagogies into a coherent whole. Course management technology allows for the digitization and delivery of pedagogies in an effective and exciting manner. Online course management options more easily enable outcome assessment and monitoring for continuous improvement.

West European magnetic confinement fusion research

International Nuclear Information System (INIS)

McKenney, B.L.; McGrain, M.; Hogan, J.T.; Porkolab, M.; Thomassen, K.I.

1990-01-01

This report presents a technical assessment and review of the West European program in magnetic confinement fusion by a panel of US scientists and engineers active in fusion research. Findings are based on the scientific and technical literature, on laboratory reports and preprints, and on the personal experiences and collaborations of the panel members. Concerned primarily with developments during the past 10 years, from 1979 to 1989, the report assesses West European fusion research in seven technical areas: tokamak experiments; magnetic confinement technology and engineering; fusion nuclear technology; alternate concepts; theory; fusion computations; and program organization. The main conclusion emerging from the analysis is that West European fusion research has attained a position of leadership in the international fusion program. This distinction reflects in large measure the remarkable achievements of the Joint European Torus (JET). However, West European fusion prominence extends beyond tokamak experimental physics: the program has demonstrated a breadth of skill in fusion science and technology that is not excelled in the international effort. It is expected that the West European primacy in central areas of confinement physics will be maintained or even increased during the early 1990s. The program's maturity and commitment kindle expectations of dramatic West European advances toward the fusion energy goal. For example, achievement of fusion breakeven is expected first in JET, before 1995

Optimal Face-Iris Multimodal Fusion Scheme

Directory of Open Access Journals (Sweden)

Omid Sharifi

2016-06-01

Full Text Available Multimodal biometric systems are considered a way to minimize the limitations raised by single traits. This paper proposes new schemes based on score level, feature level and decision level fusion to efficiently fuse face and iris modalities. Log-Gabor transformation is applied as the feature extraction method on face and iris modalities. At each level of fusion, different schemes are proposed to improve the recognition performance and, finally, a combination of schemes at different fusion levels constructs an optimized and robust scheme. In this study, CASIA Iris Distance database is used to examine the robustness of all unimodal and multimodal schemes. In addition, Backtracking Search Algorithm (BSA, a novel population-based iterative evolutionary algorithm, is applied to improve the recognition accuracy of schemes by reducing the number of features and selecting the optimized weights for feature level and score level fusion, respectively. Experimental results on verification rates demonstrate a significant improvement of proposed fusion schemes over unimodal and multimodal fusion methods.

Symmetric fusion of heavy ions around the Coulomb barrier energy

International Nuclear Information System (INIS)

Royer, G.; Remaud, B.

1983-01-01

Using the liquid drop model, we have performed a systematic study of the symmetric fusion with a neck degree of freedom and tunnelling effects, the nuclear potential being calculated with the proximity approach. Barrier heights and positions are in very good agreement with experimental data when they are known (light-medium systems); the recent experimental data of the reactions 58 Ni + 58 Ni and 64 Ni + 64 Ni are particularly investigated. For heavier systems double-humped fusion barriers and isomeric states are predicted which strongly limit the complete fusion probability

Excitation methods for energy dispersive analysis

International Nuclear Information System (INIS)

Jaklevic, J.M.

1976-01-01

The rapid development in recent years of energy dispersive x-ray fluorescence analysis has been based primarily on improvements in semiconductor detector x-ray spectrometers. However, the whole analysis system performance is critically dependent on the availability of optimum methods of excitation for the characteristic x rays in specimens. A number of analysis facilities based on various methods of excitation have been developed over the past few years. A discussion is given of the features of various excitation methods including charged particles, monochromatic photons, and broad-energy band photons. The effects of the excitation method on background and sensitivity are discussed from both theoretical and experimental viewpoints. Recent developments such as pulsed excitation and polarized photons are also discussed

Lithium excitation by slow H+ and He2+ ions

NARCIS (Netherlands)

Turkstra, JW; Meyer, D; Hoekstra, R; Morgenstern, R; Schweinzer, J

1999-01-01

Experimental and theoretical cross sections for the excitation of ground-state lithium by Hf and He2+ impact are presented for the 2-30 keV/amu energy regime. Li(2s) excitation up to the Li(n = 4) level was simulated by means of the atomic-orbital close-coupling method. Experimentally, absolute

Oscillations in the fusion of the Si + Si systems

International Nuclear Information System (INIS)

Aguilera R, E.F.; Kolata, J.J.; DeYoung, P.A.; Vega, J.J.

1986-02-01

Excitation functions for the yields of all the residual nuclei from the 28 Si + 28,30 and 30 Si + 30 Si reactions have been measured via the γ-ray technique for center of mass energies in the region within one and two times the Coulomb barrier.Thirteen elements were identified for the first reaction and ten for the other two. While no structure is shown by the data for the 28 + 28 Si reaction, we have found evidence for intermediate width structure in the 2α and the αpn channels in 28 Si + 30 Si and for broad structure in the total fusion cross sections for 30 Si + 30 Si. Calculations using a barrier penetration model with one free parameter reproduce the experimental results quite well. Evaporation model calculations indicate that the individual structure of the nuclei involved in the respective decay chains might have an important influence upon the deexcitation process at the energies relevant to our experiments. (Author)

Experimental studies of laser guiding and wake excitation in plasma channels

International Nuclear Information System (INIS)

Volfbeyn, P.; Lawrence Berkeley National Lab., CA

1998-06-01

This thesis presents results of experimental investigations of laser guiding in plasma channels. A new technique for plasma channel creation, the Ignitor-Heater scheme was proposed and experimentally tested in hydrogen and nitrogen. It made use of two laser pulses. The Ignitor, an ultrashort ( 17 W/cm 2 , 75fs laser pulse. The guiding properties and transmission and coupling efficiency were studied as a function of relative position of the channel and the injection pulse focus. Whereas entrance coupling efficiency into the channel was lower than expected, channel coupling to continuum losses were found to be in good agreement with analytical predictions. The authors speculate that increased coupling efficiency can be achieved through better mode matching into the channel. Analytic and numerical one dimensional (1-D), nonrelativistic theory of laser pulse propagation in underdense plasma was presented, in the context of laser wakefield acceleration. The relation between the laser pulse energy depletion, longitudinal laser pulse shape distortion, and changes in the group velocity and center wavelength was explored. 1-D theory was extended to treat the case of a laser exciting a wake in a hollow plasma channel, by making use of an energy conservation argument. Based on the results of this theory, a laser wakefield diagnostic was proposed where, by measuring the changes in phase or spectrum of the driving laser pulse, it is possible to infer the amplitude of the plasma wake

Collaborations in fusion research

International Nuclear Information System (INIS)

Barnes, D.; Davis, S.; Roney, P.

1995-01-01

This paper reviews current experimental collaborative efforts in the fusion community and extrapolates to operational scenarios for the Tokamak Physics Experiment (TPX) and the International Thermonuclear Experimental Reactor (ITER). Current requirements, available technologies and tools, and problems, issues and concerns are discussed. This paper specifically focuses on the issues that apply to experimental operational collaborations. Special requirements for other types of collaborations, such as theoretical or design and construction efforts, will not be addressed. Our current collaborative efforts have been highly successful, even though the tools in use will be viewed as primitive by tomorrow's standards. An overview of the tools and technologies in today's collaborations can be found in the first section of this paper. The next generation of fusion devices will not be primarily institutionally based, but will be national (TPX) and international (ITER) in funding, management, operation and in ownership of scientific results. The TPX will present the initial challenge of real-time remotely distributed experimental data analysis for a steady state device. The ITER will present new challenges with the possibility of several remote control rooms all participating in the real-time operation of the experimental device. A view to the future of remote collaborations is provided in the second section of this paper

Disentangling unisensory from fusion effects in the attentional modulation of McGurk effects: a Bayesian modeling study suggests that fusion is attention-dependent

DEFF Research Database (Denmark)

Schwartz, Jean-Luc; Tiiippana, Kaisa; Andersen, Tobias

2010-01-01

The McGurk effect has been shown to be modulated by attention. However, it remains unclear whether attentional effects are due to changes in unisensory processing or in the fusion mechanism. In this paper, we used published experimental data showing that distraction of visual attention weakens th...... Selection criterion. Our findings suggest that distraction of visual attention affects fusion by decreasing the weight of the visual input.......The McGurk effect has been shown to be modulated by attention. However, it remains unclear whether attentional effects are due to changes in unisensory processing or in the fusion mechanism. In this paper, we used published experimental data showing that distraction of visual attention weakens...... the McGurk effect, to fit either the Fuzzy Logical Model of Perception (FLMP) in which the fusion mechanism is fixed, or a variant of it in which the fusion mechanism could be varied depending on attention. The latter model was associated with a larger likelihood when assessed with a Bayesian Model...

Multifrequency Excitation of a Clamped-Clamped Microbeam

KAUST Repository

Jaber, Nizar R.

2016-01-20

We present analytical and experimental investigation of an electrically actuated clamped-clamped microbeam under a twosource harmonic excitation. The first frequency is swept around the first mode of vibration where the second one is fixed. These microbeams are fabricated using polyimide as structural layer coated with nickel form top and chromium and gold layers from bottom. We demonstrate the excitation of additive and subtractive type resonance. We show that by properly tuning the frequency and the amplitude of the excitation force, the frequency bandwidth of the resonator is increased. Theoretically, we solved the eigenvalue problem for different axial forces to find the natural frequencies ratio that match the experimental values. Using Galerkin method, a reduced order model is derived to simulate the static and dynamic response of the device where using three symmetric mode shapes provided a good agreement with experimental data. © Copyright 2015 by ASME.

Neutral beam systems for the magnetic fusion program

International Nuclear Information System (INIS)

Beal, J.W.; Staten, H.S.

1977-01-01

The attainment of economic, safe fusion power has been described as the most sophisticated scientific problem ever attacked by mankind. The presently established goal of the magnetic fusion program is to develop and demonstrate pure fusion central electric power stations for commercial applications. Neutral beam heating systems are a basic component of the tokamak and mirror experimental fusion plasma confinement devices. The requirements placed upon neutral beam heating systems are reviewed. The neutral beam systems in use or being developed are presented. Finally, the needs of the future are discussed

The role of fusion as a future power source

International Nuclear Information System (INIS)

Kintner, E.E.; Hirsch, R.L.

1977-01-01

Nations of western Europe, Japan, the Soviet Union, and the United States are working together to demonstrate the practicality of fusion power early in the 21st century. Many difficult engineering problems make fusion development one of the most formidable scientific and technological challenges ever attempted. However, the outlook is promising for achieving an inexhaustible energy source that is safe, economic, and with acceptable environmental effects. The United States magnetic fusion power development program aims at producing fusion energy experimentally in the early 1980's and demonstrating power production on a commercial scale before 2000. This prognosis reflects the confidence gained in scientific successes of the late 1960's through the present. However, many physics problems remain to be solved and many complex engineering problems without obvious solutions await attention. In response to experimental successes and the perceived importance of the fusion energy alternative, the United States effort has grown rapidly. Scientific investigations of plasma physics continue while planned engineering studies lead toward the practical goal of a commercial technology that will take a prominent place among available energy sources of the next century. Development of laser and electron beam fusion proceeds. Alternative fusion devices are investigated for their potential feasibility while the tokamak configuration is used for principal experimental devices. A national program plan and budget coordinates the efforts of federal laboratories, universities and industry. The utilities industry conducts an independent program which is increasingly coordinated with government-sponsored activity. Fusion energy programs of several nations benefit one another and should cooperate more closely in specific problem areas. Achievement of practical fusion power could be advanced through more effective mutually supporting fusion development programs. The economic and technical

Small suppression of the complete fusion of {sup 6}Li + {sup 28}Si reaction at near barrier energies

Energy Technology Data Exchange (ETDEWEB)

Sinha, Mandira [Bose Institute, Department of Physics, Kolkata (India); Lubian, J. [Universidade Federal Fluminense, Instituto de Fisica, Niteroi, Rio de Janeiro (Brazil)

2017-11-15

The incomplete fusion cross section of the {sup 6}Li + {sup 28}Si weakly bound system at above barrier energies was deduced from the measured γ-ray cross sections. The complete fusion cross section was estimated from the measured total fusion and incomplete fusion cross section and is found to be 85-100% of the total fusion cross section. The coupled channel calculation has been performed considering ground and first excited states of {sup 28}Si target. The fusion cross section estimated from coupled channel calculation shows good agreement with measured total fusion cross section at higher energies. The suppression of about 15% of the fusion cross section predicted by coupled channel calculation shows good agreement with the complete fusion cross section. The effect of the channel couplings on the elastic scattering angular distribution is also investigated. (orig.)

Inertial fusion: strategy and economic potential

International Nuclear Information System (INIS)

Nuckolls, J.H.

1983-01-01

Inertial fusion must demonstrate that the high target gains required for practical fusion energy can be achieved with driver energies not larger than a few megajoules. Before a multi-megajoule scale driver is constructed, inertial fusion must provide convincing experimental evidence that the required high target gains are feasible. This will be the principal objective of the NOVA laser experiments. Implosions will be conducted with scaled targets which are nearly hydrodynamically equivalent to the high gain target implosions. Experiments which demonstrate high target gains will be conducted in the early nineties when multi-megajoule drivers become available. Efficient drivers will also be demonstrated by this time period. Magnetic fusion may demonstrate high Q at about the same time as inertial fusion demonstrates high gain. Beyond demonstration of high performance fusion, economic considerations will predominate. Fusion energy will achieve full commercial success when it becomes cheaper than fission and coal. Analysis of the ultimate economic potential of inertial fusion suggests its costs may be reduced to half those of fission and coal. Relative cost escalation would increase this advantage. Fusions potential economic advantage derives from two fundamental properties: negligible fuel costs and high quality energy (which makes possible more efficient generation of electricity)

Coulomb Excitation of Neutron Deficient Sn-Isotopes using REX-ISOLDE

CERN Multimedia

Di julio, D D; Kownacki, J M; Marechal, F; Andreoiu, C; Siem, S; Perrot, F; Van duppen, P L E; Napiorkowski, P J; Iwanicki, J S

2002-01-01

It is proposed to study the evolution of the reduced transition probabilities, B(E2; 0$^{+} \\rightarrow$ 2$^{+}$), for neutron deficient Sn isotopes by Coulomb excitation in inverse kinematics using REX-ISOLDE and the MINIBALL detector array. Measurements of the reduced transition matrix element for the transition between the ground state and the first excited 2$^{+}$ state in light even-even Sn isotopes provide a means to study e.g. core polarization effects in the $^{100}$Sn core. Previous attempts to measure this quantity have been carried out using the decay of isomeric states populated in fusion evaporation reactions. We thus propose to utilize the unique opportunity provided by REX-ISOLDE, after the energy upgrade to 3.1 MeV/u, to use the more model-independent approach of Coulomb excitation to measure this quantity in a number of isotopes in this region.

Fusion-fission dynamics

International Nuclear Information System (INIS)

Blocki, J.; Planeta, R.; Brzychczyk, J.; Grotowski, K.

1992-01-01

Classical dynamical calculations of the heavy ion induced fission processes have been performed for the reactions 40 Ar+ 141 Pr, 20 Ne+ 165 Ho and 12 C+ 175 Lu leading to the iridium like nucleus. As a result prescission lifetimes were obtained and compared with the experimental values. The comparison between the calculated and experimental lifetimes indicates that the one-body dissipation picture is much more relevant in describing the fusion-fission dynamics than the two-body one. (orig.)

Quantum propagator approach to heavy-ion fusion

International Nuclear Information System (INIS)

Bao, J.D.

2002-01-01

The real-time path integral propagator approach is used to study the fusion probability of massive nuclei including quantum effect. An analytical expression of the probability to pass over barrier of an inverted harmonic potential is obtained, in which both height and curvature of the barrier are controlled by the neck degree of freedom. The fusion probability of three systems in central collision as a function of the center of mass energy are calculated and compared to experimental results. It is shown that the quantum fluctuation enhances the fusion probability at low energies, and the neck fluctuation makes the slope of the fusion probability curve become flatter. (author)

Transference of particles in the fusion process of 6He + 209Bi

International Nuclear Information System (INIS)

Lizcano, D.; Aguilera, E.F.; Martinez Q, E.

2000-01-01

In a recent work were reported measurements done to energy which was to the Coulomb barrier for the 6 He + 209 Bi system. The fusion excitation function measured for this system shows a strong enhancement with respect to the predictions of the penetration model of unidimensional barrier at minor energies to the Coulombian barrier. In basis with the results obtained for different degrees of freedom it was determined with the CCDEF code, that the transfer of 2 neutrons of 6 He to binding states to 209 Bi, producing 211 Bi, is the mechanism looked as the best candidate for explain the great enhancement in the fusion excitation function of this system at energies under Coulomb barrier. It is corroborated what was affirmed by others authors about the strength value at 1.5 MeV as a typical value for the transference of two particles between the projectile and the target. (Author)

Physics of mirror fusion systems

International Nuclear Information System (INIS)

Post, R.F.

1976-01-01

Recent experimental results with the 2XIIB mirror machine at Lawrence Livermore Laboratory have demonstrated the stable confinement of plasmas at fusion temperatures and with energy densities equaling or exceeding that of the confining fields. The physics of mirror confinement is discussed in the context of these new results. Some possible approaches to further improving the confinement properties of mirror systems and the impact of these new approaches on the prospects for mirror fusion reactors are discussed

Evaluation of multimodality imaging using image fusion with ultrasound tissue elasticity imaging in an experimental animal model.

Science.gov (United States)

Paprottka, P M; Zengel, P; Cyran, C C; Ingrisch, M; Nikolaou, K; Reiser, M F; Clevert, D A

2014-01-01

To evaluate the ultrasound tissue elasticity imaging by comparison to multimodality imaging using image fusion with Magnetic Resonance Imaging (MRI) and conventional grey scale imaging with additional elasticity-ultrasound in an experimental small-animal-squamous-cell carcinoma-model for the assessment of tissue morphology. Human hypopharynx carcinoma cells were subcutaneously injected into the left flank of 12 female athymic nude rats. After 10 days (SD ± 2) of subcutaneous tumor growth, sonographic grey scale including elasticity imaging and MRI measurements were performed using a high-end ultrasound system and a 3T MR. For image fusion the contrast-enhanced MRI DICOM data set was uploaded in the ultrasonic device which has a magnetic field generator, a linear array transducer (6-15 MHz) and a dedicated software package (GE Logic E9), that can detect transducers by means of a positioning system. Conventional grey scale and elasticity imaging were integrated in the image fusion examination. After successful registration and image fusion the registered MR-images were simultaneously shown with the respective ultrasound sectional plane. Data evaluation was performed using the digitally stored video sequence data sets by two experienced radiologist using a modified Tsukuba Elasticity score. The colors "red and green" are assigned for an area of soft tissue, "blue" indicates hard tissue. In all cases a successful image fusion and plan registration with MRI and ultrasound imaging including grey scale and elasticity imaging was possible. The mean tumor volume based on caliper measurements in 3 dimensions was ~323 mm3. 4/12 rats were evaluated with Score I, 5/12 rates were evaluated with Score II, 3/12 rates were evaluated with Score III. There was a close correlation in the fused MRI with existing small necrosis in the tumor. None of the scored II or III lesions was visible by conventional grey scale. The comparison of ultrasound tissue elasticity imaging enables a

Characterization of incomplete fusion in the reactions Ar + KCl at 32,40,52 and 74 MeV/u

International Nuclear Information System (INIS)

Bisquer, E.

1996-01-01

Heavy ion collisions at intermediate energies (10 to 100 A.MeV) have been investigated and gave evidence to the persistence of so-called low energy mechanisms such as incomplete fusion. This thesis aims at determining the energy threshold beyond which such a mechanism does not occur any more. First we investigated the so-called conventional incomplete fusion. This mechanism is well known from low energy studies: a thermalized compound nucleus is formed which further de-excites by evaporating particles. Residues will be therefore detected in coincidence with mainly light particles. Ar + KCl at incident energies of 32, 40, 52 and 74 A.MeV has been selected for this analysis. These experiments have been performed using the INDRA multidetector in GANIL (Caen). The detection performance of INDRA allowed to use new analysis methods via global variables. In a first step, global variables have been compared in order to find the one that is the most appropriate to our study. Then incomplete fusion events have been extracted from raw events recorded at incident energies of 32, 40 and 52 A.MeV. It turned out that the contribution of this mechanisms was very weak at 52. A.MeV. It turned out that the contribution of this mechanism was very weak at 52 A.MeV and even zero at 74 A.MeV. We then investigated events in which three fragments were detected which could possibly sign multifragmentation. We did not find instantaneous multifragmentation with any expansion contribution. We also performed BNV simulations in order to compare our experimental results to model predictions, solving in a semi-classical way the Vlasov transport equation. A good agreement has been obtained on the size of the compound nucleus formed. However the excitation energy has not been reproduced, as the code seems to overestimate the energy taken away by preequilibrium particles. Incomplete fusion decreases as a function of energy but is not replaced by instantaneous multifragmentation with any expansion

Prospects for Tokamak Fusion Reactors

International Nuclear Information System (INIS)

Sheffield, J.; Galambos, J.

1995-01-01

This paper first reviews briefly the status and plans for research in magnetic fusion energy and discusses the prospects for the tokamak magnetic configuration to be the basis for a fusion power plant. Good progress has been made in achieving fusion reactor-level, deuterium-tritium (D-T) plasmas with the production of significant fusion power in the Joint European Torus (up to 2 MW) and the Tokamak Fusion Test Reactor (up to 10 MW) tokamaks. Advances on the technologies of heating, fueling, diagnostics, and materials supported these achievements. The successes have led to the initiation of the design phases of two tokamaks, the International Thermonuclear Experimental Reactor (ITER) and the US Toroidal Physics Experiment (TPX). ITER will demonstrate the controlled ignition and extended bum of D-T plasmas with steady state as an ultimate goal. ITER will further demonstrate technologies essential to a power plant in an integrated system and perform integrated testing of the high heat flux and nuclear components required to use fusion energy for practical purposes. TPX will complement ITER by testing advanced modes of steady-state plasma operation that, coupled with the developments in ITER, will lead to an optimized demonstration power plant

Inertial fusion in the nineties

International Nuclear Information System (INIS)

Harris, D.; Dudziak, D.J.; Cartwright, D.C.

1987-01-01

The 1980s have proven to be an exciting time for the inertial confinement fusion (ICF) program. Major new laser and light-ion drivers have been constructed and have produced some encouraging results. The 1990s will be a crucial time for the ICF program. A decision for proceeding with the next facility is scheduled for the early 1990s. If the decision is positive, planning and construction of this facility will occur. Depending on the time required for design and construction, this next-generation facility could become operational near the turn of the century

Status report on controlled thermonuclear fusion

International Nuclear Information System (INIS)

1990-06-01

The International Fusion Research Council (IFRC), an advisory body to the International Atomic Energy Agency, reports on the current status of fusion; this report updates its 1978 status report. This report contains a General Overview and Executive Summary, and reports on all current approaches to fusion throughout the world; a series of technical reports is to be published elsewhere. This report is timely in that it not only shows progress which has occurred over the past, but interfaces with possible future devices, in particular the International Thermonuclear Experimental Reactor (ITER), whose conceptual design phase is nearing completion. 5 refs, 6 figs

Review of the conceptual design of a Doublet fusion experimental power reactor

International Nuclear Information System (INIS)

Baker, C.C.

1976-01-01

The results of a two-year, conceptual design study of a fusion experimental power reactor (EPR) are presented. For this study, the primary objectives of the EPR are to obtain plasma ignition conditions and produce net electrical power. The design features a Doublet plasma configuration with a major radius of 4.5 m. The average plasma beta is 10 percent which yields a thermonuclear power level of 410 MW during a 105-sec burn period. With a duty factor of 0.84, the gross electrical output is 124 MW(e) while the net output is 37 MW(e). The design features a 25-cm-thick, helium-cooled, modular, stainless-steel blanket with a 1-cm-thick, silicon carbide first wall. Sufficient shielding is provided to permit contact maintenance outside the shield envelope within 24 hr after shutdown. An overall plant concept has been developed including a superheated steam cycle power conversion system. Preliminary cost estimates and construction schedules have also been developed. 3 refs

Fusion of 110Pd with 110Pd

International Nuclear Information System (INIS)

Morawek, W.

1991-07-01

In the framework of this thesis the excitation functions of the systems 110 Pd + 110 Pd and 110 Pd + 104 Ru could be measured. The evaporation-residual-nucleus cross sections is deviating from lighter systems dominated by channels, which arise from evaporation of α particles. In the reaction 110 Pd + 110 Pd no xn channels were observed. In comparison to other reactions qualitatively a strong fusion hindrance of this system is shown. (orig./HSI) [de

Public Relations on Fusion in Europe

Science.gov (United States)

Ongena, J.; van Oost, G.; Paris, P. J.

2000-10-01

A summary will be presented of PR efforts on fusion energy research in Europe. A 3-D movie of a fusion research experimental reactor has been realized at the start of this year. It has been made entirely on virtual animation basis. Two versions exists, a short version of 3 min., as a video clip, and a longer version of nearly 8 min. Both could be viewed in 3D, using special projections and passive glasses or in normal VHS video projections. A new CD-ROM for individual and classroom use will be presented, discussing (i) the different energy forms, (ii) general principles of fusion, (iii) current research efforts and (iv) future prospects of fusion. This CD-ROM is now produced in English, German, French, Spanish, Italian and Portuguese Several new brochures and leaflets intended to increase the public awareness on fusion in Europe will be on display.

Fusion enhancement in the reactions of neutron-rich nuclei

International Nuclear Information System (INIS)

Bian Baoan; Zhang Fengshou; Zhou Hongyu

2009-01-01

The neutron-rich fusion reactions are investigated systematically using the improved isospin dependent quantum molecular dynamics model. By studying the systematic dependence of fusion barrier on neuron excess, we find the enhancement of the fusion cross sections for neutron-rich nuclear reactions that give the lowered static Coulomb barriers. The calculated fusion cross sections agree quantitatively with the experimental data. We further discuss the mechanism of the fusion enhancement of the cross sections for neutron-rich nuclear reactions by analyzing the dynamical lowering of the Coulomb barrier that is attributed to the enhancement of the N/Z ratio at the neck region.

Experimental study of deceleration process of traveling wave direct energy converter for advanced fusion

International Nuclear Information System (INIS)

Takeno, Hormasa; Yamamoto, Takayoshi; Takada, Kousuke; Yasaka, Yasuyoshi

2007-01-01

Advanced fusion is attractive in the view point of utilization of high efficiency direct energy conversion from fusion produced ions. Deuterium-helium-3 reaction is the most possible, however, the energy of created fast proton is so enormous that conventional electro-static converters cannot be applied. Use of a traveling wave direct energy converter (TWDEC), the principle of which was inverse process of a linear accelerator, was proposed for recovering energy of the fast protons. In order to realize the TWDEC, the authors are continuing experimental study by employing a small-scale simulator. A TWDEC consists of a modulator and a decelerator. Fast proton beam extracted from a reactor is introduced in the modulator where radio frequency (RF) electrostatic field modulate the beam velocity, and hence, the protons are bunched and density-modulated in the downstream. The density-modulated protons flow into the decelerator where a number of electrodes connected to a transmission circuit are axially aligned. The flowing protons induce RF current which creates RF traveling voltage on the electrodes. The RF traveling field between aligned electrodes decelerates the protons, thus their energy is recovered into RF power. In this paper, deceleration process of TWDEC is experimentally examined. In our experimental simulator, because of the small beam current, the induced potential, i.e. the deceleration field is so weak that the beam cannot be decelerated. Thus, we examined the process by dividing into two: one was induction of the deceleration field by the modulated beam, which was called as passive decelerator. The other was energy recovery through interaction between the deceleration field and the modulated beam. In this latter experiment, the deceleration field was supplied externally, and we called this as active decelerator. As for the active decelerator mode, we performed higher beam energy experiment than previous one. As the beam energy increases, the divergence of

Non-LTE effects in inertial confinement fusion target chambers

International Nuclear Information System (INIS)

MacFarlane, J.J.; Moses, G.A.; Peterson, R.R.

1989-01-01

In previous studies of transport processes in inertial confinement fusion target chambers, the radiative properties of the background plasma were calculated under the assumption of local thermodynamic equilibrium (LTE). In this paper, the authors present a study of the equation of state and the radiative properties of high temperature, low-to-moderate density ( 21 cm -3 ) plasmas for the determination of the conditions under which non-LTE effects become important and for an assessment of the importance of non-LTE processes in target chambers during high yield inertial fusion target explosions. For this purpose, two-body (radiative and dielectronic) and three-body (collisional) recombination and de-excitation processes are considered in calculating the steady state ionization and excitation populations. The results of this study indicate that non-LTE processes generally become important at temperatures of > or approx. 1, 10 and 100 eV for plasma densities of 10 18 , 10 19 and 10 21 cm -3 , respectively. Radiation hydrodynamic simulations utilizing the equation of state and the opacities for a non-LTE argon plasma were performed to study the response of a background gas to an inertial fusion target explosion. These calculations indicate that non-LTE processes are often the dominant atomic processes in the background plasma and that they can strongly affect the radiative and shock properties as energy is transported away from the point of the target explosion. (author). 22 refs, 10 figs, 1 tab

Coherent excitation of a single atom to a Rydberg state

DEFF Research Database (Denmark)

Miroshnychenko, Yevhen; Gaëtan, Alpha; Evellin, Charles

2010-01-01

We present the coherent excitation of a single Rubidium atom to the Rydberg state 58d3/2 using a two-photon transition. The experimental setup is described in detail, as are experimental techniques and procedures. The coherence of the excitation is revealed by observing Rabi oscillations between...

Bouillabaisse sushi fusion power

CERN Multimedia

2004-01-01

"If avant-garde cuisine is any guide, Japanese-French fusion does not work all that well. And the interminable discussions over the International Thermonuclear Experimental Reactor (ITER) suggest that what is true of cooking is true of physics" (1 page)

Proceedings of the second United Nations international conference on the peaceful uses of atomic energy. V. 31. Theoretical and experimental aspects of controlled nuclear fusion

International Nuclear Information System (INIS)

1958-01-01

The main topics covered by the Conference are: possibility of controlled fusion and status of the research programmes in different countries (USSR, Germany, USA, UK); theoretical aspects of plasma physics; experimental aspects of plasma physics

Advanced nuclear fuel production by using fission-fusion hybrid reactor

International Nuclear Information System (INIS)

Al-Kusayer, T.A.; Sahin, S.; Abdulraoof, M.

1993-01-01

Efforts are made at the College of Engineering, King Saud University, Riyadh to lay out the main structure of a prototype experimental fusion and fusion-fission (hybrid) reactor blanket in cylindrical geometry. The geometry is consistent with most of the current fusion and hybrid reactor design concepts in respect of the neutronic considerations. Characteristics of the fusion chamber, fusion neutrons and the blanket are provided. The studies have further shown that 1 GWe fission-fusion reactor can produce up to 957 kg/year which is enough to fuel five light water reactors of comparable power. Fuel production can be increased further. 29 refs

Fusability and fissionability in 86Kr induced reactions near and below the fusion barrier

International Nuclear Information System (INIS)

Reisdorf, W.; Hessberger, F.P.; Hildenbrand, K.D.; Hofmann, S.; Muenzenberg, G.; Schmidt, K.H.; Schneider, W.F.W.; Suemmerer, K.; Wirth, G.; Kratz, J.V.; Schlitt, K.; Sahm, C.C.

1985-04-01

Evaporation-residue excitation functions for the reactions 86 Kr + sup(70,76)Ge, sup(92,100)Mo, sup(99,102,104)Ru have been measured using activation methods and the velocity filter SHIP. The data span the region from well below the fusion barrier up to and beyond the energy where limitation by fission competition takes place. The data are shown to be compatible with the concept of complete fusion followed by the statistical decay of the equilibrated compound nucleus. Information on both the fusion probability at and below the fusion threshold and the fissionability of the compound nuclei formed is extracted. The model dependence of the extracted fission barriers is discussed in detail. In analogy to studies involving lighter projectiles, strong correlations between the low-energy nuclear-structure properties of the nuclei and the subbarrier fusion probability are found. A relative shift of the fusion barrier to higher energies, that increases with the number of valence neutrons in the target nuclei, is observed. (orig.)

Present status of fusion researches in USA, 4

International Nuclear Information System (INIS)

Yoshikawa, Shoichi; Okabayashi, Michio

1983-01-01

25 years have elapsed since nuclear fusion was published at the second Geneva conference in 1958. During this period, the Plasma Physics Laboratory of Princeton University has achieved the central role in the research on toroidal system nuclear fusion devices. Also the experiment of the large tokamak TFTR started from December, 1982, recorded the longest containment time of 200 ms as the initial data, and toroidal devices look to approach one step close to the scientific verification experiment (Q = 1) of reactors. In the PPPL, in order to perfect the basis required for the realization of nuclear fusion reactors, the experimental and theoretical developments have been carried out. Plasma containment experiment has been advanced successively from stellarater through internal conductor type to tokamak, and in plasma heating, ion cyclotron heating, fast neutral particle injection heating and low region hybrid heating were successfully carried out. As the experimental apparatuses, that for poloidal divertor experiment, Princeton large torus, tokamak fusion test reactor (TFTR) and S-1 spheromak are described. From the theories developed recently, bean type tokamak, heliac-stellarator and nuclear fusion reaction utilizing μ-mesons and nuclear spin are explained. (Kako, I.)

Excitation of giant resonances through inelastic scattering

International Nuclear Information System (INIS)

Kailas, S.

1981-01-01

In the last few years, exciting developments have taken place in the study of giant resonances (GR). In addition to the already well known gjant dipole resonance (GDR), the presence of at least two more new GRs viz. giant quadrupole resonance (GQR) and giant monopole resonance (GMR) has been experimentally established. The systematics covering these GRs is found to be consistent with the theoretical expectation. Though the existence of higher multipoles has been predjcted by theory, so far only some of these have been found to be excited experimentally. Various probe particles - electrons, protons (polarized and unpolarized), light and heavy ions and pions - at different bombarding energies have been used to excite the GR region, primarily through the inelastic scattering process. Detailed experiments, looking at the decay modes of GR region, have also been performed. These studies have contributed significantly to a better understanding of the phenomenon of nuclear collective excitation. In this report, the current status of 'GR' research is reviewed. (author)

Development of fusion safety standards

International Nuclear Information System (INIS)

Longhurst, G.R.; Petti, D.A.; Dinneen, G.A.; Herring, J.S.; DeLooper, J.; Levine, J.D.; Gouge, M.J.

1996-01-01

Two new U.S. Department of Energy (DOE) standards have been prepared to assist in the design and regulation of magnetic fusion facilities. They are DOE-STD-6002-96, 'Safety of Magnetic Fusion Facilities - Requirements,' and DOE-STD-6003-96 'Safety of Magnetic Fusion Facilities - Guidance.' The first standard sets forth requirements, mostly based on the Code of Federal Regulations, deemed necessary for the safe design and operation of fusion facilities and a set of safety principles to use in the design. The second standard provides guidance on how to meet the requirements identified in DOE-STD-6002-96. It is written specifically for a facility such as the International Thermonuclear Experimental Reactor (ITER) in the DOE regulatory environment. As technical standards, they are applicable only to the extent that compliance with these standards is included in the contracts of the developers. 7 refs., 1 fig

Nuclear data for fusion reactor technology

International Nuclear Information System (INIS)

1988-06-01

The meeting was organized in four sessions and four working groups devoted to the following topics: Requirements of nuclear data for fusion reactor technology (6 papers); Status of experimental and theoretical investigations of microscopic nuclear data (10 papers); Status of existing libraries for fusion neutronic calculations (5 papers); and Status of integral experiments and benchmark tests (6 papers). A separate abstract was prepared for each of these papers

Experimental progress and innovation on the HL-2A tokamak