Hasil untuk "Nuclear and particle physics. Atomic energy. Radioactivity"

A. Quadling

This paper represents one half of a set of two, covering the TECHNOLOGY presentations at the Fusion Energy Conference (FEC), held in London, UK, in October 2023. Dominant themes include the use of computing codes to pre-determine machine performance in fusion device design, the impetus that ITER and DEMO are providing for component fabrication innovation, and a growing global focus on blanket materials and fuel retention mechanisms. New themes include power plant costing and the control of activated corrosion products. Stellarator technology is noted, but this is not yet a strong innovation theme at FEC. The latest fusion material science considers operating conditions in power plant service, especially the impact of fuel cycle and superconducting magnet fields; fuel cycle technologies consider electrical coupling and the need for insulating components to control the magnetohydrodynamic response. Optimising correction coils and the thickness of Toroidal Field components to withstand loads is becoming increasing critical in next-step machine design. The latter increasingly utilises integrated frameworks for high-fidelity modelling. Whether coupling armour, blanket and shielding or dose rate fields with geometry, these platforms require high-performance computing. With respect to power plant programmes, the DEMO design continues to assume pulsed operation; JA DEMO, with or without neutral beam injection, sees the electron cyclotron scenario enabling 2 h of pulsed operation at 80 MW of external heating and current drive power. Spherical tokamak work —from the development of the Spherical Tokamak Advanced Reactor in the USA for substantial reduction in weight and cost, to the Spherical Tokamak with Toroidal Magnetic Field 3 T in Mexico, continues to gain momentum. Regulatory approaches are steering away from typical nuclear fission traditions. New safety focus is emerging around transport of activated corrosion products. Outreach on the benefits of fusion must be couched in the framework of legacy, as viewed by a new generation of power stakeholders.

Matthew J. Blacker, Nele Callebaut, Blanca Hergueta et al.

Abstract We employ an ADM deparametrization strategy to discuss the radial canonical formalism of asymptotically AdS3 gravity. It leads to the identification of a radial ‘time’ before quantization, which is the volume time, canonically conjugate to York time. Holographically, this allows to interpret the semi-classical path integral of T T ¯ $$ T\overline{T} $$ theory as a Schrödinger wavefunctional satisfying a Schrödinger evolution equation in volume time, and the T T ¯ $$ T\overline{T} $$ operator expectation value in terms of the Hamiltonian that generates volume time translations — both consistent with cut-off holography. We make use of the canonical perspective to construct the rotating BTZ solution from the Hamilton-Jacobi equation, with a finite cut-off energy spectrum that has a known holographic T T ¯ $$ T\overline{T} $$ interpretation, as well as semi-classical Wheeler-DeWitt states for that solution.

M. Kupczynski

In physics, we construct idealized mathematical models in order to explain various phenomena which we observe or create in our laboratories. In this article, I recall how sophisticated mathematical models evolved from the concept of a number created thousands of years ago, and I discuss some challenges and open questions in quantum foundations and in the Standard Model. We liberated nuclear energy, landed on the Moon and built ‘quantum computers’. Encouraged by these successes, many believe that when we reconcile general relativity with quantum theory we will have the correct theory of everything. Perhaps we should be much humbler. Our perceptions of reality are biased by our senses and by our brain, bending them to meet our priors and expectations. Our abstract mathematical models describe only in an approximate way different layers of physical reality. To describe the motion of a meteorite, we can use a concept of a material point, but the point-like approximation breaks completely when the meteorite hits the Earth. Similarly, thermodynamic, chemical, molecular, atomic, nuclear and elementary particle layers of physical reality are described using specific abstract mathematical models and approximations. In my opinion, the theory of everything does not exist.

Pietro Pelliconi, Julian Sonner

Abstract Open quantum systems are defined as ordinary unitary quantum theories coupled to a set of external degrees of freedom, which are introduced to take on the rôle of an unobserved environment. Here we study examples of open quantum field theories, with the aid of the so-called Feynman-Vernon Influence Functional (“IF”), including field theories that arise in holographic duality. We interpret the system in the presence of an IF as an open effective field theory, able to capture the effect of the unobserved environment. Our main focus is on computing Rényi and entanglement entropies in such systems, whose description from the IF, or “open EFT”, point of view we develop in this paper. The issue of computing the entanglement-Rényi entropies in open quantum systems is surprisingly rich, and we point out how different prescriptions for the IF may be appropriate depending on the application of choice. A striking application of our methods concerns the fine-grained entropy of subsystems when including gravity in the setup, for example when considering the Hawking radiation emitted by black holes. In this case we show that one prescription for the IF leads to answers consistent with unitary evolution, while the other merely reproduces standard EFT results, well known to be inconsistent with unitary global evolution. We establish these results for asymptotically AdS gravity in arbitrary dimensions, and illustrate them with explicit analytical expressions for the IF in the case of matter-coupled JT gravity in two dimensions.

P. Chiovaro, A. Quartararo, P. Avona et al.

In water-cooled nuclear reactors, the issue of neutron-activated products transport along the primary heat transfer system (PHTS) is very demanding, as it is a coupled neutronic/fluid-dynamic problem requiring a challenging balance between accuracy and reasonable computational time. This work addresses the transport of water activation products in large hydraulic circuits. Regarding the nuclear calculations, the assessment of the production rates of the radioisotope concentrations has been performed by Monte Carlo analyses adopting the MCNP5.1.6 code, while for the transportation calculations, an innovative method has been expressly developed. It foresees a one-dimensional nodalization, in a MATLAB-Simulink environment, of the hydraulic circuit considered with a computational fluid-dynamic (CFD) characterization (by ANSYS CFX code) of the nodes under neutron flux, that is the components where radioisotopes are formed, and the highest gradients of concentration are present. The method was compared with one-dimensional models not supported by fluid-dynamic analysis. The results of this comparison showed that in cases involving fairly complicated geometries and radioisotopes with a small half-life, CFD analyses are necessary to achieve adequate accuracy. The procedure was applied to very large and rather complex hydraulic circuits like the divertor PHTSs of DEMO fusion reactor to obtain the concentrations of the activation products of the water constituents ( ^16 N, ^17 N, ^19 O, ^14 C, ^41 Ar) along such systems.

Sergio L. Cacciatori, Samuel Grushevsky, Alexander A. Voronov

Abstract We present a complete computation of superstring scattering amplitudes at tree level, for the case of Neveu-Schwarz insertions. Mathematically, this is to say that we determine explicitly the superstring measure on the moduli space M 0 , n , 0 $$ {\mathcal{M}}_{0,n,0} $$ of super Riemann surfaces of genus zero with n ≥ 3 Neveu-Schwarz punctures. While, of course, an expression for the measure was previously known, we do this from first principles, using the canonically defined super Mumford isomorphism [1]. We thus determine the scattering amplitudes, explicitly in the global coordinates on M 0 , n , 0 $$ {\mathcal{M}}_{0,n,0} $$ , without the need for picture changing operators or ghosts, and are also able to determine canonically the value of the coupling constant. Our computation should be viewed as a step towards performing similar analysis on M 0 , 0 , n $$ {\mathcal{M}}_{0,0,n} $$ , to derive explicit tree-level scattering amplitudes with Ramond insertions.

A. M. Nagaraja, K. Sridhar, L. Seenappa et al.

Gennady V. Mishinsky

The main directions of V.I.Vernadsky's scientific activity during the period of the scientific revolution occurred at the end of the 19th and until the middle of the20th centuries are briefly listed. His decisive contribution to the initial research and practical application of the phenomenon of radioactivity and nuclear physics is shown. Based on the discovery of low-energy nuclear reactions more than 30 years ago, the development of Vernadsky's ideas about the role of radioactivity − the transformation of some chemical elements into other chemical elements − in geology, in the thermal balance of the Earth, in the prevalence of trace chemical elements is presented. Main provisions of the theory of low-energy nuclear reactions in condensed matter are listed: the threshold for excitation of the medium is indicated; shown is the possibility of generating a strong magnetic field in a unidirectional flow of electrons in a quasineutral plasma with the pairing of free electrons, and, subsequently, the pairing of atomic electrons into orthobosons with the latter forming a Bose-Einstein condensate, in which a new state of matter is formed − transatoms, which are combined, due to their ultra-strong magnetic fields, into nuclear transmolecule, in which multinuclear transmutation reactions occur with non-radioactive products; with the transformation of transmolecules into different sets of stable nuclei, subject to all conservation laws. In this case, the collective parameter that characterizes the quasi-equilibrium distribution of the mass numbers of isotopes – reaction products – is the “thermodynamic” coefficient of the energy content of the medium. Natural nucleosynthesis in the era of recombination of the Universe, which gave rise to the formation and development of organic chemical, and subsequently biochemical synthesis, is described. The development of Vernadsky's doctrine of the biosphere and noosphere of the Earth is supplemented by the concept of fractality of material, including biological structures with the further evolution of living matter, as well as by the concept of planetary nucleosynthesis. Starting from the idea of planetary nucleosynthesis, based on the mechanism of multinuclear quantum transitions of some atomic nuclei to others, a new doctrine of the geological development of the Earth and the foundations of quantum planetology were formulated, which explained the strict temporal cyclicity observed in the geological activity of the Earth associated with galactic jet energy flows. The issues discussed may become a basis for those directions in scientific research that will form a new paradigm, a new worldview.

F. Bock, N. Schmidt, P. Wang et al.

We describe the design and performance the calorimeter systems used in the ECCE detector design to achieve the overall performance specifications cost-effectively with careful consideration of appropriate technical and schedule risks. The calorimeter systems consist of three electromagnetic calorimeters, covering the combined pseudorapdity range from -3.7 to 3.8 and two hadronic calorimeters. Key calorimeter performances which include energy and position resolutions, reconstruction efficiency, and particle identification will be presented.

Antonio Amariti, Massimo Bianchi, Marco Fazzi et al.

Abstract We study various orientifold projections of 4d N $$ \mathcal{N} $$ = 1 toric gauge theories, associated with CY singularities known as L a,b,a /ℤ2, with a + b even. We obtain superconformal chiral theories that have the same central charge, anomalies and superconformal index, whereas they were different before the orientifold. Some of these projections are implemented by a novel type of orientifold without fixed loci, known as glide orientifold. We claim that these theories flow to the same conformal manifold, and they are connected by quadratic exactly marginal deformations. The latter can be written in terms of conjugate pairs of bifundamental fields of R-charge one, generalizing previous results for unoriented non-chiral theories.

Ekta Chaubey, Ina Hönemann, Stefan Weinzierl

Abstract We consider the full set of master integrals with internal top-and W-propagators contributing to the three-loop Higgs self-energy diagrams of order O $$ \mathcal{O} $$ (α 2 α s ). We split the master integrals into a system relevant to the Feynman diagrams proportional to the product of Yukawa couplings y b y t and the complement. For both systems we define master integrals of uniform weight, such that the associated differential equation is in ε-factorised form. The occurring square roots are rationalised and all master integrals are expressible in multiple polylogarithms.

B. Albertazzi, P. Mabey, Th. Michel et al.

The interaction between a molecular cloud and an external agent (e.g., a supernova remnant, plasma jet, radiation, or another cloud) is a common phenomenon throughout the Universe and can significantly change the star formation rate within a galaxy. This process leads to fragmentation of the cloud and to its subsequent compression and can, eventually, initiate the gravitational collapse of a stable molecular cloud. It is, however, difficult to study such systems in detail using conventional techniques (numerical simulations and astronomical observations), since complex interactions of flows occur. In this paper, we experimentally investigate the compression of a foam ball by Taylor–Sedov blast waves, as an analog of supernova remnants interacting with a molecular cloud. The formation of a compression wave is observed in the foam ball, indicating the importance of such experiments for understanding how star formation is triggered by external agents.

A. Kievsky, L. Girlanda

S. Acharya, D. Adamová, A. Adler et al.

A.I. Alikhanyan National Science Laboratory (Yerevan Physics Insti- tute) Foundation (ANSL), State Committee of Science and World Federation of Scientists (WFS), Armenia; Austrian Academy of Sciences, Austrian Science Fund (FWF): [M 2467- N36] and Nationalstiftung fur Forschung, Technologie und Entwicklung, Austria; Ministry of Communications and High Technologies, National Nuclear Research Center, Azerbaijan; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Financiadora de Estudos e Projetos (Finep), Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) and Universidade Federal do Rio Grande do Sul (UFRGS), Brazil; Ministry of Education of China (MOEC), Ministry of Science & Technology of China (MSTC) and National Natural Science Foundation of China (NSFC), China; Ministry of Science and Education and Croatian Science Foundation, Croatia; Centro de Aplicaciones Tecnologi- cas y Desarrollo Nuclear (CEADEN), Cubaenergia, Cuba; Ministry of Education, Youth and Sports of the Czech Republic, Czech Republic; The Danish Council for Independent Research | Natural Sciences, the VILLUM FONDEN and Danish National Research Foun- dation (DNRF), Denmark; Helsinki Institute of Physics (HIP), Finland; Commissariat a l’Energie Atomique (CEA) and Institut National de Physique Nucleaire et de Physique des Particules (IN2P3) and Centre National de la Recherche Scientifique (CNRS), France; Bundesministerium fur Bildung und Forschung (BMBF) and GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Germany; General Secretariat for Research and Technol- ogy, Ministry of Education, Research and Religions, Greece; National Research, Develop- ment and Innovation Office, Hungary; Department of Atomic Energy Government of India (DAE), Department of Science and Technology, Government of India (DST), University Grants Commission, Government of India (UGC) and Council of Scientific and Industrial Research (CSIR), India; Indonesian Institute of Science, Indonesia; Centro Fermi — MuseoStorico della Fisica e Centro Studi e Ricerche Enrico Fermi and Istituto Nazionale di Fisica Nucleare (INFN), Italy; Institute for Innovative Science and Technology, Nagasaki Insti- tute of Applied Science (IIST), Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and Japan Society for the Promotion of Science (JSPS) KAK- ENHI, Japan; Consejo Nacional de Ciencia (CONACYT) y Tecnologia, through Fondo de Cooperacion Internacional en Ciencia y Tecnologia (FONCICYT) and Direccion Gen- eral de Asuntos del Personal Academico (DGAPA), Mexico; Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands; The Research Council of Norway, Nor- way; Commission on Science and Technology for Sustainable Development in the South (COMSATS), Pakistan; Pontificia Universidad Catolica del Peru, Peru; Ministry of Sci- ence and Higher Education, National Science Centre and WUT ID-UB, Poland; Korea Institute of Science and Technology Information and National Research Foundation of Ko- rea (NRF), Republic of Korea; Ministry of Education and Scientific Research, Institute of Atomic Physics and Ministry of Research and Innovation and Institute of Atomic Physics, Romania; Joint Institute for Nuclear Research (JINR), Ministry of Education and Science of the Russian Federation, National Research Centre Kurchatov Institute, Russian Science Foundation and Russian Foundation for Basic Research, Russia; Ministry of Education, Science, Research and Sport of the Slovak Republic, Slovakia; National Research Foun- dation of South Africa, South Africa; Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW), Sweden; European Organization for Nuclear Research, Switzerland; Suranaree University of Technology (SUT), National Science and Technology Development Agency (NSDTA) and Office of the Higher Education Commission under NRU project of Thailand, Thailand; Turkish Atomic Energy Agency (TAEK), Turkey; Na- tional Academy of Sciences of Ukraine, Ukraine; Science and Technology Facilities Council (STFC), United Kingdom; National Science Foundation of the United States of America (NSF) and United States Department of Energy, Office of Nuclear Physics (DOE NP), United States of America.

Abdulrahim Al Balushi, Zhencheng Wang, Donald Marolf

Abstract We generalize the Gao-Jafferis-Wall construction of traversable two-sided wormholes to multi-boundary wormholes. In our construction, we take the background spacetime to be multi-boundary black holes in AdS3. We work in the hot limit where the dual CFT state in certain regions locally resembles the thermofield double state. Furthermore, in these regions, the hot limit makes the causal shadow exponentially small. Based on these two features of the hot limit, and with the three-boundary wormhole as our main example, we show that traversability between any two asymptotic regions in a multi-boundary wormhole can be triggered using a double-trace deformation. In particular, the two boundary regions need not have the same temperature and angular momentum. We discuss the non-trivial angular dependence of traversability in our construction, as well as the effect of the causal shadow region.

Massimo Tinto

This article discusses the potential advantages of a data processing technique for continuous gravitational wave signals searches in the data measured by ground-based gravitational wave interferometers. Its main advantage over other techniques is that it does not need to search over the signal’s direction of propagation. Although it is a “coherent method” (i.e., it coherently processes year-long data), it is applied to a data set obtained by multiplying the original time-series with a (half-year) time-shifted copy of it. As a result, the phase modulation due to the interferometer motion around the Sun is automatically canceled in the signal of the synthesized time-series. Although the resulting signal-to-noise ratio is not as high as that of a coherent search, it equals that of current hierarchical methods. In addition, since the signal search is performed over a parameters space of smaller dimensionality, the associated false-alarm probability should be smaller than those characterizing hierarchical methods and result in an improved likelihood of detection.

Jidapa Bridhikitti, MD, Jason K. Viehman, W. Scott Harmsen et al.

Purpose: Radiation therapy (RT) is the standard treatment for patients with inoperable skin malignancies of the head and neck region (H&N), and as adjuvant treatment post surgery in patients at high risk for local or regional recurrence. This study reports clinical outcomes of intensity-modulated proton therapy (IMPT) for these malignancies. Materials and Methods: We retrospectively reviewed cases involving 47 patients with H&N malignancies of the skin (squamous cell, basal cell, melanoma, Merkel cell, angiosarcoma, other) who underwent IMPT for curative intent between July 2016 and July 2019. Overall survival was estimated via Kaplan-Meier analysis, and oncologic outcomes were reported as cumulative incidence with death as a competing risk. Results: The 2-year estimated local recurrence rate, regional recurrence rate, local regional recurrence rate, distant metastasis rate, and overall survival were 11.1% (95% confidence interval [CI], 4.1%–30.3%), 4.4% (95% CI, 1.1%–17.4%), 15.5% (95% CI, 7%-34.3%), 23.4% (95% CI, 5.8%–95.5%), and 87.2% (95% CI, 75.7%–100%), respectively. No patient was reported to have a grade 3 or higher adverse event during the last week of treatment or at the 3-month follow-up visit. Conclusion: IMPT is safe and effective in the treatment of skin malignancies of the H&N.

SONG Zhihao;ZHANG Yunhan;WANG Ning;GUO Hongli;ZHAO Hailong;GAO Xiang

The use of the chromatographic method to extract 99Tcm from the low specific activity 99Mo solution is an effective way to obtain medical isotope 99Tcm that meeting clinical requirements. It has been reported that the separation technologies must use strong acid or strong alkaline solutions, which require additional treatments. Exploring the method of separating technetium from neutral molybdenum solution can simplify the treatment process. A kind of activated carbon fiber was used to extract technetium from neutral low specific activity 99Mo (＜0.2 Ci/g Mo) in 1 mol/L NaCl solution. Neutral eluent was used to desorb technetium throughout the process, and the separation of molybdenum and technetium was realized. The recoveries of 99Tcm were more than 90%. The obtained sodium pertechnetate ［99Tcm］ injection met the requirements of the Chinese Pharmacopoeia without pH adjustation, and the labeling rate of MIBI and MDP for met the Chinese Pharmacopoeia claim. The results show that the extraction of 99Tcm from 99Mo with low specific activity (<0.2 Ci/g Mo), independent intellectual property rights and obvious advantages is formed, which provides technical reserves for potential methods of preparing 99Tcm.

S. Graves, R. Flynn, D. Hyer

PURPOSE Rapid adoption of targeted radionuclide therapy as an oncologic intervention has motivated the development of patient-specific voxel-wise approaches to radiation dosimetry. These approaches often rely on pre-tabulated dose point kernels for convolution-based calculations, however, these dose kernels are sparse in literature and often have sub-optimal characteristics. The purpose of this work was to generate an extensive library of dose point kernels with sufficient size and resolution for general clinical application of voxel-wise dosimetry. METHODS Nuclear data were acquired for 2,174 radionuclides from the National Nuclear Data Center (Brookhaven National Laboratory, accessed March 2018). Based on these data, isotropic point sources of radioactivity in water were simulated using Monte Carlo N-Particle transport v6.2 (MCNP6.2, Los Alamos National Laboratory). Simulations were separated by emission type for each radionuclide - photons (γ-rays, x-rays), beta particles (positrons, electrons); and discrete electrons (conversion electrons, Auger electrons, Coster-Kronig electrons). Dose was tallied in concentric spherical shells about the point source using an energy deposition pulse-height tally (MCNP *F8 tally). Bins were spaced every 0.1 mm until a radius of 10 cm, and every 1 mm until a radius of 2 m. Positron emissions where treated as electrons for transport, with annihilation photons generated at the origin within the photon simulation. Alpha particle emissions were not simulated since their energy is deposited within ~0.2 mm of the source. Neutron and spallation effects were not considered. A subset of the resultant dose point kernels (11 C, 18 F, 32 P, 52g Mn, 64 Cu, 67 Ga, 89 Sr, 89 Zr, 90 Y, 99m Tc, 111 In, 117m Sn, 123 I, 124 I, 125 I, 131 I, 153 Sm, 177 Lu, 186 Re, 188 Re, 211 As, 212 Pb, 213 Bi, 223 Ra, and 225 Ac) were evaluated for accuracy based on conservation of energy, comparison to kernels in the literature, and statistical precision. RESULTS Among dose point kernels that were manually reviewed, good agreement with previously published dose point kernels was observed. Energy within the kernels was found to be conserved to within 1% of the value expected from nuclear data, suggesting that a radius of 2 m was sufficient to capture the almost all of the energy released during decay for all isotopes considered. Local dosimetric uncertainty, evaluated at the radius of 99% energy deposition, was found to be less than 9% for all radioisotopes evaluated. Re-binning data more coarsely by a factor of 10, similar to what would be done for a clinical dose calculation, results in all evaluated kernels having a relative error of less than 1.1% at R50% , 1.5% at R90% , and 2.7% at R99% (the radius corresponding to 50%, 90%, and 99% of total energy deposition, respectively). The kernels produced in this work have been made freely available (https://zenodo.org/record/2564036). CONCLUSIONS An extensive library of high-resolution radial dose kernels was generated and validated against published data. In addition to enabling patient-specific voxel-wise internal dosimetry by convolution superposition, the generated dose point kernels data may prove useful to the wider health physics community. This article is protected by copyright. All rights reserved.

P. Butler, L. Gaffney, L. Gaffney et al.

There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, which would indicate CP violation and hence probe physics beyond the Standard Model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we observed the low-lying quantum states in 224Rn and 226Rn by accelerating beams of these radioactive nuclei. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment. Octupole deformation in nuclei is important to understand nuclear structure and electric dipole moments of heavy atoms. Here the authors measure energies of excited quantum states in radon isotopes and find that these isotopes do not provide favourable conditions in the search for CP-violation.