Download or read book Characterization of the New Neutron Line at CERN n TOF and Study of the Neutron induced Fission of 237Np written by Yonghao Chen and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The neutron time-of-flight (n_TOF)facility at CERN is a unique worldwide pulsedneutron source to measure the nuclear data over thewidest energy range with two beam lines currentlyexploited. One is horizontal with a ~185 metersflight path, sending neutrons to experimental area-1(EAR-1). The second one is a new line sendingneutrons vertically to experimental area-2 (EAR-2)with a ~20 meters flight path.The first part of this PhD work is dedicated to thecharacterization of the beam (flux, geometricalprofile, energy spectrum) of the new EAR-2 neutronbeam, of the utmost importance for the experimentalproposals and analyses. An experiment was carriedout at EAR-2, based on PPAC detectors looking atfission of 235U, and the beam profile and neutronflux have been obtained for the entire availableenergy range (from thermal to 200 MeV).The second part of the thesis aims to study theneutron-induced fission of 237Np. 237Np isabundantly produced in present nuclear reactor andis one of the major long-lived components ofnuclear waste which can be considered as apotential target of incineration in fast neutronreactors. Consequently its neutron-induced fissioncross section has been measured at differentfacilities. However, significant discrepancies existbetween different experiments. Especially, therecent one performed at n_TOF in 2010 is about 6%higher by comparison to the evaluation data basedon previous experiments. Therefore an experimenthas been performed at n_TOF EAR-1 to measure itsfission cross section, in a configuration allowing anaccurate control of the detection efficiency, aimingto give a definite answer to the puzzle. In this work,we found that the efficiencies for different targetelements are different, even though they havesimilar thickness, reflecting the conditions ofelectrodeposition. After application of thisefficiency correction in the energy range from 1 to 5MeV, the newly extracted fission cross section is 2-3% lower compared with our previous measurementin 2010, however they are 3-4% higher than the.
Download or read book The Neutron written by Hans G. Börner and published by World Scientific. This book was released on 2012 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reactor-based laboratory at the Institut Laue-Langevin is recognized as the world's most productive and reliable source of slow neutrons for the study of low energy particle and nuclear physics. The book highlights the impact of about 600 very diverse publications about work performed in these fields during the past more than 30 years of reactor operation at this institute. On one hand neutrons are used as a tool to generate nuclei in excited states for studying their structure and decay, in particular fission. Uniquely sensitive experiments can tell us a great deal about the symmetry characteristics of nuclei and their fission properties. On the other hand, studies with slow neutrons as the object of investigation are complementary to studies at huge particle accelerators. Experiments carried out at the ILL contribute to elucidate basic questions about the building blocks of the Universe by analyzing very precisely subtle neutron properties.
Download or read book Fission Neutrons written by Nikolay Kornilov and published by Springer. This book was released on 2014-07-25 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although the fission of heavy nuclei was discovered over 75 years ago, many problems and questions still remain to be addressed and answered. The reader will be presented with an old, but persistent problem of this field: The contradiction between Prompt Fission Neutron (PFN) spectra measured with differential (microscopic) experiments and integral (macroscopic and benchmark) experiments (the Micro-Macro problem). The difference in average energy is rather small ~3% but it is stable and we cannot explain the difference due to experimental uncertainties. Can we measure the PFN spectrum with high accuracy? How may we compare results of different experiments to provide better accuracy? Are our traditional theoretical models correct? What can be done to solve the Micro-Macro problem in future? These questions are discussed in this monograph for the reader. The current work will be of interest to graduate students and researchers, particularly those working in nuclear and neutron physics.
Download or read book Neutron The A Tool And An Object In Nuclear And Particle Physics written by Hans G Borner and published by World Scientific. This book was released on 2012-02-10 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reactor-based laboratory at the Institut Laue-Langevin is recognized as the world's most productive and reliable source of slow neutrons for the study of low energy particle and nuclear physics. The book highlights the impact of about 600 very diverse publications about work performed in these fields during the past more than 30 years of reactor operation at this institute. On one hand neutrons are used as a tool to generate nuclei in excited states for studying their structure and decay, in particular fission. Uniquely sensitive experiments can tell us a great deal about the symmetry characteristics of nuclei and their fission properties. On the other hand, studies with slow neutrons as the object of investigation are complementary to studies at huge particle accelerators. Experiments carried out at the ILL contribute to elucidate basic questions about the building blocks of the Universe by analyzing very precisely subtle neutron properties.
Download or read book The N TOF Facility Neutron Beams for Challenging Future Measurements at CERN written by Enrico Chiaveri and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The CERN n_TOF neutron beam facility is characterized by a very high instantaneous neutron flux, excellent TOF resolution at the 185)m long flight path (EAR-1), low intrinsic background and coverage of a wide range of neutron energies, from thermal to a few GeV. These characteristics provide a unique possibility to perform high-accuracy measurements of neutron-induced reaction cross-sections and angular distributions of interest for fundamental and applied Nuclear Physics. Since 2001, the n_TOF Collaboration has collected a wealth of high quality nuclear data relevant for nuclear astrophysics, nuclear reactor technology, nuclear medicine, etc. The overall efficiency of the experimental program and the range of possible measurements has been expanded with the construction of a second experimental area (EAR-2), located 20)m on the vertical of the n_TOF spallation target. This upgrade, which benefits from a neutron flux 30 times higher than in EAR-1, provides a substantial extension in measurement capabilities, opening the possibility to collect data on neutron cross-section of isotopes with short half-lives or available in very small amounts. This contribution will outline the main characteristics of the n_TOF facility, with special emphasis on the new experimental area. In particular, we will discuss the innovative features of the EAR-2 neutron beam that make possible to perform very challenging measurements on short-lived radioisotopes or sub-mg samples, out of reach up to now at other neutron facilities around the world. Finally, the future perspectives of the facility will be presented.
Download or read book Study of Fission Neutron Spectra with High energy Activation Detectors written by J. A. Grundl and published by . This book was released on 1963 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fission And Properties Of Neutron rich Nuclei Proceedings Of The Fifth International Conference On Icfn5 written by Joseph H Hamilton and published by World Scientific. This book was released on 2013-09-16 with total page 746 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings are the fifth in the series of International Conferences covering fission and properties of neutron-rich nuclei, which are at the forefront of nuclear research. The time interval of 5 years between each conference allows for significant new results to be achieved. Recently, world leaders in theory and experiments in research and the development of new facilities for research presented their latest results in areas such as synthesis of superheavy elements, new facilities for and recent results with radioactive ion beams, structure of neutron-rich nuclei, nuclear fission process, fission yields and nuclear astrophysics. This book is a major source of the latest research in these areas and plans for the future. The conference brought together a unique group of over 100 speakers including leaders from the major nuclear laboratories in Canada, China, France, Finland, Germany, Italy, Japan, Russia, Switerzland and the US along with leading research scientists from around the world.
Download or read book An Analysis of the Published Data Concerning Neutron Induced Fission of Pu 239 written by Manbir Singh Kathuria and published by . This book was released on 1969 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurements of Delayed Neutron Yields from Thermal Neutron Induced Fission of 235U 233U 239Pu and 237Np written by S. B. Borzakov and published by . This book was released on 1998 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Neutron Production in the M2 Muon Beam Line at Cern written by Emily Draeger and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Measurement Programme at the Neutron Time of flight Facility N TOF at CERN written by Frank Gunsing and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron-induced reaction cross sections are important for a wide variety of research fields ranging from the study of nuclear level densities, nucleosynthesis to applications of nuclear technology like design, and criticality and safety assessment of existing and future nuclear reactors, radiation dosimetry, medical applications, nuclear waste transmutation, accelerator-driven systems and fuel cycle investigations. Simulations and calculations of nuclear technology applications largely rely on evaluated nuclear data libraries. The evaluations in these libraries are based both on experimental data and theoretical models. CERN's neutron time-of-flight facility n_TOF has produced a considerable amount of experimental data since it has become fully operational with the start of its scientific measurement programme in 2001. While for a long period a single measurement station (EAR1) located at 185 m from the neutron production target was available, the construction of a second beam line at 20 m (EAR2) in 2014 has substantially increased the measurement capabilities of the facility. An outline of the experimental nuclear data activities at n_TOF will be presented.
Download or read book New Prospects in Synthesis and Study of Neutron Rich Heavy Nuclei written by Valery I. Zagrebaev and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present limits of the upper part of the nuclear map are rather close to the beta stability line while the unexplored area of heavy neutron rich nuclides (also those located along the neutron closed shell N = 126 to the right hand side of the stability line) is extremely important for nuclear astrophysics investigations and, in particular, for the understanding of the r-process of astrophysical nucleogenesis. For elements with Z > 100 only neutron deficient isotopes (located to the left of the stability line) have been synthesized so far. The “north-east” area of the nuclear map can be reached neither in fusion-fission reactions nor in fragmentation processes widely used nowadays for the production of new nuclei. Multi-nucleon transfer processes in near barrier collisions of heavy ions seem to be the only reaction mechanism allowing us to produce and explore neutron rich heavy nuclei including those located at the superheavy island of stability. Neutron capture process can be also considered as an alternative method for the production of long-lived neutron rich superheavy nuclei. Strong neutron fluxes might be provided by nuclear reactors and nuclear explosions in laboratory frame and by supernova explosions in nature.
Download or read book Numerical results of a 2E 2v measurement for fast neutron induced fission of 1hn2 1hn3 1hn5U and 1hn2 1hn3 1hn7Np written by and published by . This book was released on 1981 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Results of a 2E 2v measurement for Fast Neutron Induced Fission of 235U and 237Np written by and published by . This book was released on 1981 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A STUDY OF THE ELECTRON LINE SPECTRA OF CERTAIN NEUTRON INDUCED RADIOACTIVITIES written by and published by . This book was released on 1951 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atlas of Neutron Resonances written by Said F. Mughabghab and published by Elsevier. This book was released on 2006-04-04 with total page 1373 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Atlas of Neutron Resonances provides detailed information on neutron resonances, thermal neutron cross sections, and average resonance properties which are important to neutron physicist, astrophysicists, solid state physicists, reactor engineers, scientists involved in activation analysis, and evaluators of neutron cross sections. · Compilation and evaluation of the world's thermal neutron cross-sections and resonance parameters for neutron physicists, reactor engineers, and neutron evaluators.· Compilation and evaluation of coherent scattering lengths for solid state physicists and evaluators· Compilation and evaluation of average 30-keV capture cross sections for astrophysicists.· Nuclear level density parameters derived from average spacings of neutron resonances following a new approach (new feature for this edition).· Brief review of sub-threshold fission.· Comparisons of optical model predictions with neutron strength function data and scattering lengths.· Estimation of average E1 radiative widths on the basis of the generalized Landau-Fermi liquid model (a new feature for this edition).
Download or read book Study of Neutron Correlations in Spontaneous and Neutron Induced Fission written by and published by . This book was released on 2014 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
