DOCSLIB.ORG

A Photofission Delayed Γ-Ray Spectra Calculation Tool for the Conception of a Nuclear Material Characterization Facility

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Photofission Delayed Γ-Ray Spectra Calculation Tool for the Conception of a Nuclear Material Characterization Facility EPJ Web of Conferences 170, 06001 (2018) https://doi.org/10.1051/epjconf/201817006001 ANIMMA 2017 A Photofission Delayed γ-ray Spectra Calculation Tool for the Conception of a Nuclear Material Characterization Facility D. BERNARD*, O. SEROT*, E. SIMON*, L. BOUCHER* and S. PLUMERI+ packages are made of concrete in a big cylindrical container of Abstract—The photon interrogation analysis is a non- more than 800 L. Despite of the photon attenuation through destructive technique allowing to identify and quantify fissile concrete, the photon interrogation is one of the most ambitious materials in nuclear waste packages. This paper details an ways to interrogate the waste package. The photon pulsed automatic procedure which has been developed to simulate the beam is generated by an electron convertor made of tungsten delayed γγγ-ray spectra for several actinide photofissions. This calculation tool will be helpful for the fine conception or other metal (copper, silicon,…) allowing the (collimation, shielding, noise background optimizations, etc.) and Bremsstrahlung emission. The LINAC maximum energy is for the on-line analysis of such a facility. supposed to be flexible between 15 to 25 MeV. During this irradiation phase (roughly 2 to 3 hours), the waste package is Index Terms—Photonic Interrogation, Nuclear Material axially rotating to make uniform the irradiation dose. The Characterization, Photofission Yields, Delayed γγγ, Decay Data. beam is then stopped and after a reasonable decay time (1 to 5 minutes), High Purity Germanium detectors are deployed all around the package to permit the photon spectrum acquisition I. INTRODUCTION for a large duration (around 2 to 3 hours). This photon HIS paper proposes a new tool to help the conception of a spectrum contains delayed γ-rays and X-rays emitted by the Tnew facility in order to detect and distinguish actinides in fission products decay. Its analysis then gives the quantitative a waste package. The technique used is based on the analysis information on the fissile mass present in the waste container. of delayed photons emitted after photon-burst-induced The next sections will be devoted to the developed tools to fissions. Because of the difference on fission yields, the perform the fine conception of this facility. delayed photons spectra are a signature of different actinides, if any. The first section will present the overall studied facility for the III. BATEMAN EQUATIONS photon beam inducing fissions and the delayed gamma The irradiation phase and the cooling/acquisition phase will detection set-up. The second part will be devoted to the be described sequentially. specific developed tool, called DEGAS (Delayed Gamma Spectrum), to obtain γ spectra (including fission yields and decay data libraries, Bateman depletion equations solving - A. Irradiation Phase involving numerical issues and the verification of the whole 1) Statement of the problem procedure). At the end, we will propose an automated tool to γ-induced fission of actinides leads to around 1000 select specific γ-ray lines ratios to detect a specific actinide in independent fission products for which we have to calculate the waste package. the atomic number densities , at a given time , by solving the coupled Bateman equations [1] : II. THE EXAMINATION FACILITY () This facility, under design phase, has to detect the amount of actinides and to distinguish uranium from plutonium species in nuclear waste packages. Some of these waste = − + (1) Paper submitted to ANIMMA conference for proceedings and to IEEE + () transactions in June 2017. This work was supported by the CEA/DEN and The first two terms are associated to decay probabilities ( ) ANDRA/R&D collaborative project DISN/ANDRA/CHK/A-CARAC-01-12. * and branching ratios ( ) for the disappearance and creation of CEA/DEN/DER&DTN Cadarache, F-13108 Saint-Paul-Lez-Durance, France, corresponding authors: [email protected], [email protected], the fission product (based on the specific JEFF-3.1.1/Decay [email protected], [email protected]. Data Library [2]). The last term involves the production rate + ANDRA, 1-7 rue Jean Monnet, F-92290 Châtenay-Malabry, France, by folding (with respect to the incident photon energy ) the corresponding author : [email protected]. photofission cross section ( ) of the fissile actinide times its © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/). EPJ Web of Conferences 170, 06001 (2018) https://doi.org/10.1051/epjconf/201817006001 ANIMMA 2017 independent fission yield ( ) to the incident photon flux . - The photofission cross sections are taken heavy mass region (around the mass 140) and (5) The number density is calculated at the distance (location consequently a shift of the mass yield in the light mass from the ENDF/B-VII.1 library [4] (,)for major actinides of the fission event) from the center of the cylindrical waste 235,238 238,239,240,241 241 region from one fissioning nucleus to another, which ( U, Pu, Am) and from the TENDL- () = () − 242 242m package. The latter is rotating during this irradiation phase 2015 library [5] for Pu and Am: ensures the conservation of the fissioning nucleus mass Where the user’s input data stand for the distance with a period close to 2 to 3 minutes. (removing the prompt neutron multiplicity). of the fissile material from the center of the waste package, the In order to solve equation (1), we assume first the , , 0.020 10 distance between the conversion target and the package = 2⁄ 400 238 decoupling in energy, space and time of the photon incident Pu (ENDF\B7.1) 239Pu (ENDF\B7.1) surface and finally, the package radius, respectively. 350 240Pu (ENDF\B7.1) flux . In addition, since 241 0.016 Pu (ENDF\B7.1) 242Pu (TENDL-2015) the rotation period of the waste package is much lower than 300 2) Solving the Bateman equations , , = ×() ×() 1 the irradiation time, the time dependent production term is 250 0.012 For a given fissile nucleus amount, we will solve the reduced to the averaged value. By this way, equation (1) is previously described equation 2. The user has to fix a given 200 transformed into the following equation: 0.008 238 mass and the location in the waste package for this 150 Pu 239 0.1 Pu particular isotope. The boundary conditions impose that no 100 240 0.004 Pu fission product are present before the irradiation in the waste 241 BremsstrahlungSpectrum Pu 50 (%) Yield Post-neutron 242 package, . PhotofissionCross Section [mb] Pu We decide to use the DARWIN code package [8] to solve ≅ − + + × ( ) × (2) 0 0.000 6 8 101214161820 0.01 such equations, (= because) = of its robustness but also because it Where: 80 90 100 110 120 130 140 150 160 Incident Gamma Energy [MeV] contains already preprocessed nuclear data libraries. This code - stands for the energy-averaged independent 10 Fig. 2. Evaluated photofission cross sections (left axis) with incident γ- package is able to solve non homogeneous differential isotopic fission product yield for an actinide , spectrum (dashed line, right axis). equation but the source term has to be associated to neutron - its specific fission rate (relative to the mass induced production and not to photon induced reactions. One - The independent fission product yield for a given that we look for). 1 can analytically demonstrate that solving the following () fissioning nucleus at a given incident energy, homogeneous and time-iterative system (see lower case for For a given fissile isotope and by identification of equation is determined from a Monte Carlo code “homogeneous” number densities ): (1) and equation (2), the effective yield is defined as: called GEF (acronym for GEneral description of 235 , 0.1 U Fission observables) [6]. This code first calculates 238 U fission fragment yields before prompt neutron 241Am (6) Post-neutron Yield (%) Yield Post-neutron 242m (3) emission, from the concept of fission modes developed Am = − + ∑ (,) by Brosa [7]. These fission modes correspond to the 0.01 = (. ) = . (). (,) various valleys observed in the deformation potential 80 90 100 110 120 130 140 150 160 leads to the following actual number densities which solve Where: energy surface of the fissioning nucleus. When the Mass equation (2): - The incident γ-spectrum is calculated with nucleus starts its deformation from the ground state up Fig. 3. Independent effective fission (15MeV+W) mass yields obtained from to the scission point, it follows one of those valleys (7) MCNPX [3] and depends on the electron/photon the GEF code (version 2015 V2.2) [6]. conversion target and on the maximum energy of the with a given probability. The depth and width of each () = ∑ ( − . ) LINAC (see figure 1). mode are determined in order to deduce the main The average excitation energy available for a given Our developed DEGAS tool is using a MATLAB® [9] properties of the fission fragments (yield, deformation fissioning nucleus can be easily calculated: script which reads first the output file from the GEF 100 at scission, kinetic energy…). In a second step, the total simulation ( ), produces and submits a DARWIN input file excitation energy available at scission is calculated and (owing to the user specifications - -) in a second shared between the two nascent fragments. Finally, (4) Simulation 15 MeV step, and then calculates the atomic number densities at the (,) , Simulation 20 MeV thanks to a statistical treatment, the emission of prompt end of the irradiation phase: from equation (6). -1 10 Simulation 25 MeV < >= neutrons and prompt gammas are simulated to predict (,) their properties (energy spectrum, multiplicity ...). In These energies are reported in Tab. 1 for all fissioning () this way, the GEF code is able to calculate almost all nuclei investigated in the present work.
Load more

Recommended publications
  • The R-Process Nucleosynthesis and Related Challenges
    EPJ Web of Conferences 165, 01025 (2017) DOI: 10.1051/epjconf/201716501025 NPA8 2017 The r-process nucleosynthesis and related challenges Stephane Goriely1,, Andreas Bauswein2, Hans-Thomas Janka3, Oliver Just4, and Else Pllumbi3 1Institut d’Astronomie et d’Astrophysique, Université Libre de Bruxelles, CP 226, 1050 Brussels, Belgium 2Heidelberger Institut fr¨ Theoretische Studien, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany 3Max-Planck-Institut für Astrophysik, Postfach 1317, 85741 Garching, Germany 4Astrophysical Big Bang Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan Abstract. The rapid neutron-capture process, or r-process, is known to be of fundamental importance for explaining the origin of approximately half of the A > 60 stable nuclei observed in nature. Recently, special attention has been paid to neutron star (NS) mergers following the confirmation by hydrodynamic simulations that a non-negligible amount of matter can be ejected and by nucleosynthesis calculations combined with the predicted astrophysical event rate that such a site can account for the majority of r-material in our Galaxy. We show here that the combined contribution of both the dynamical (prompt) ejecta expelled during binary NS or NS-black hole (BH) mergers and the neutrino and viscously driven outflows generated during the post-merger remnant evolution of relic BH-torus systems can lead to the production of r-process elements from mass number A > 90 up to actinides. The corresponding abundance distribution is found to reproduce the∼ solar distribution extremely well. It can also account for the elemental distributions observed in low-metallicity stars. However, major uncertainties still affect our under- standing of the composition of the ejected matter.
    [Show full text]
  • Photofission Cross Sections of 238U and 235U from 5.0 Mev to 8.0 Mev Robert Andrew Anderl Iowa State University
    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1972 Photofission cross sections of 238U and 235U from 5.0 MeV to 8.0 MeV Robert Andrew Anderl Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Nuclear Commons, and the Oil, Gas, and Energy Commons Recommended Citation Anderl, Robert Andrew, "Photofission cross sections of 238U and 235U from 5.0 MeV to 8.0 MeV " (1972). Retrospective Theses and Dissertations. 4715. https://lib.dr.iastate.edu/rtd/4715 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS This dissertation was produced from a microfilm copy of the original document. While the most advanced technological means to photograph and reproduce this document have been used, the quality is heavily dependent upon the quality of the original submitted. The following explanation of techniques is provided to help you understand markings or patterns which may appear on this reproduction, 1. The sign or "target" for pages apparently lacking from the document photographed is "Missing Page(s)". If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting thru an image and duplicating adjacent pages to insure you complete continuity, 2.
    [Show full text]
  • Photofission Cross Sections of 232Th and 236U from Threshold to 8
    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1972 Photofission cross sections of 232Th nda 236U from threshold to 8 MeV Michael Vincent Yester Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Nuclear Commons Recommended Citation Yester, Michael Vincent, "Photofission cross sections of 232Th nda 236U from threshold to 8 MeV " (1972). Retrospective Theses and Dissertations. 6137. https://lib.dr.iastate.edu/rtd/6137 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS This dissertation was produced from a microfilm copy of the original document. While the most advanced technological means to photograph and reproduce this document have been used, the quality is heavily dependent upon the quality of the original submitted. The following explanation of techniques is provided to help you understand markings or patterns which may appear on this reproduction. 1. The sign or "target" for pages apparently lacking from the document photographed is "Missing Page(s)". If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting thru an image and duplicating adjacent pages to insure you complete continuity. 2. When an image on the film is obliterated with a large round black mark, it is an indication that the photographer suspected that the copy may have moved during exposure and thus cause a blurred image.
    [Show full text]
  • The R-Process Nucleosynthesis During the Decompression of Neutron Star Crust Material
    Journal of Physics: Conference Series PAPER • OPEN ACCESS Related content - The Impact of Fission on R-Process The r-process nucleosynthesis during the Calculations M Eichler, A Arcones, R Käppeli et al. decompression of neutron star crust material - Variances in r-process predictions from uncertain nuclear rates Matthew Mumpower, Rebecca Surman To cite this article: S Goriely et al 2016 J. Phys.: Conf. Ser. 665 012052 and Ani Aprahamian - Discovery of a strongly r-process enhanced extremely metal-poor star LAMOST J110901.22plus075441.8 Hai-Ning Li, Wako Aoki, Satoshi Honda et View the article online for updates and enhancements. al. This content was downloaded from IP address 188.184.3.52 on 18/01/2018 at 15:57 Nuclear Physics in Astrophysics VI (NPA6) IOP Publishing Journal of Physics: Conference Series 665 (2016) 012052 doi:10.1088/1742-6596/665/1/012052 The r-process nucleosynthesis during the decompression of neutron star crust material S Goriely1,ABauswein2,H-TJanka2, S Panebianco3, J-L Sida3,J-F Lemaˆıtre3, S Hilaire4, N Dubray4 1 Institut d’Astronomie et d’Astrophysique, ULB, CP226, 1050 Bruxelles, Belgium 2 Max-Planck-Institut f¨urAstrophysik, Postfach 1317, 85741 Garching, Germany 3 CEA Saclay, Irfu/Service de Physique Nuclaire, 91191 Gif-sur-Yvette, France 4 CEA, DAM, DIF, F-91297 Arpajon, France E-mail: [email protected] Abstract. About half of the nuclei heavier than iron observed in nature are produced by the so-called rapid neutron capture process, or r-process, of nucleosynthesis. The identification of the astrophysics site and the specific conditions in which the r-process takes place remains, however, one of the still-unsolved mysteries of modern astrophysics.
    [Show full text]
  • Effect of Gamma-Strength on Nuclear Reaction Calculations
    Effect of gamma-strength on nuclear reaction calculations Igor Kadenko1, Vladimir Plujko1,*, Borys Bondar1, Oleksandr Gorbachenko1, Borys Leshchenko2, Kateryna Solodovnyk1, Oleksandr Tkach1, and Viktor Zheltonozhskyi3. 1Nuclear Physics Department, Taras Shevchenko National University, Kyiv, Ukraine 2National Technical University of Ukraine “Kyiv Polytechnic Institute”, Kyiv, Ukraine 3Nuclear Structure Department, Institute for Nuclear Research of NAS, Kyiv, Ukraine Abstract. The results of the study of gamma-transition description in fast neutron capture and photofission are presented. Recent experimental data were used, namely, the spectrum of prompt gamma-rays in the energy range 2÷18 MeV from 14-MeV neutron capture in natural Ni and isomeric ratios in primary fragments of photofission of the isotopes of U, Np and Pu by bremsstrahlung with end-point energies Ee= 10.5, 12 and 18 MeV. The data are compared with the theoretical calculations performed within EMPIRE 3.2 and TALYS 1.6 codes. The mean value of angular momenta and their distributions were determined in the primary fragments 84Br, 97Nb, 90Rb, 131,133Te, 132Sb, 132,134I, 135Xe of photofissions. An impact of the characteristics of nuclear excited states on the calculation results is studied using different models for photon strength function and nuclear level density. determination of mean angular momenta in primary fragments is analyzed. 1 Introduction Nuclear reactions with different projectiles provide an 2 Experimental data information on properties of the excited nuclear states and nuclear reaction mechanisms. They are also Figure 1 demonstrates comparison of our recent required to different applications. Specifically, data of experimental data [4] for γ-spectrum from (n,x γ ) (n,x γ ) reactions with any outgoing particle (x) and reactions on natNi with the earlier data from EXFOR gamma-rays for atomic nuclei of the reactor materials database [5-8].
    [Show full text]
  • Photonuclear Reactions of Actinide and Pre-Actinide Nuclei at Intermediate Energies
    Photonuclear reactions of actinide and pre-actinide nuclei at intermediate energies Tapan Mukhopadhyay1 and D.N. Basu2 Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700 064, India ∗ (Dated: August 9, 2021) Photonuclear reaction is described with an approach based on the quasideuteron nuclear pho- toabsorption model followed by the process of competition between light particle evaporation and fission for the excited nucleus. Thus fission process is considered as a decay mode. The evaporation- fission process of the compound nucleus is simulated in a Monte-Carlo framework. Photofission reaction cross sections are analysed in a systematic manner in the energy range ∼ 50-70 MeV for the actinides 232Th, 233U, 235U, 238U and 237Np and the pre-actinide nuclei 208Pb and 209Bi. The study reproduces satisfactorily well the available experimental data of photofission cross sections at energies ∼ 50-70 MeV and the increasing trend of nuclear fissility with the fissility parameter Z2/A for the actinides and pre-actinides at intermediate energies [∼ 20-140 MeV]. Keywords: Photonuclear reactions; Photofission; Nuclear fissility; Monte-Carlo PACS numbers: 25.20.-x, 27.90.+b, 25.85.Jg, 25.20.Dc, 24.10.Lx I. INTRODUCTION Isotopes of plutonium and other actinides tend to be long-lived with half-lives of many thousands of years, whereas radioactive fission products tend to be shorter- In recent years the study of photofission has attracted lived (most with half-lives of 30 years or less). Many of considerable interest. When a gamma (photon) above the actinides are very radiotoxic because they also have the nuclear binding energy of an element is incident on long biological half-lives and are α emitters as well.
    [Show full text]
  • Photofission Analysis for Fissile Dosimeters Dedicated to Reactor
    EPJ Web of Conferences 106, 02007 (2016) DOI: 10.1051/epjconf/201610602007 C Owned by the authors, published by EDP Sciences, 2016 Photofission Analysis for Fissile Dosimeters Dedicated to Reactor Pressure Vessel Surveillance Stéphane Bourganel1,a , Margaux Faucher2, and Nicolas Thiollay3 1 CEA Saclay, DEN/DANS/DM2S/SERMA/LPEC, 91191 Gif-sur-Yvette Cedex, France 2 PHELMA, 3 Parvis Louis Néel - CS 50257, 38016 Grenoble Cedex 1, France 3 CEA Cadarache, DEN/DER/SPEx/LDCI, 13108 Saint Paul Lez Durance Cedex, France Abstract. Fissile dosimeters are commonly used in reactor pressure vessel surveillance programs. In this paper, the photofission contribution is analyzed for in-vessel 237Np and 238U fissile dosimeters in French PWR. The aim is to reassess this contribution using recent tools (the TRIPOLI-4 Monte Carlo code) and latest nuclear data (JEFF3.1.1 and ENDF/B- VII nuclear libraries). To be as exhaustive as possible, this study is carried out for different configurations of fissile dosimeters, irradiated inside different kinds of PWR: 900 MWe, 1300 MWe, and 1450 MWe. Calculation of photofission rate in dosimeters does not present a major problem using the TRIPOLI-4® Monte Carlo code and the coupled neutron-photon simulation mode. However, preliminary studies were necessary to identify the origin of photons responsible of photofissions in dosimeters in relation to the photofission threshold reaction (around 5 MeV). It appears that the main contribution of high enough energy photons generating photofissions is the neutron inelastic scattering in stainless steel reactor structures. By contrast, 137Cs activity calculation is not an easy task since photofission yield data are known with high uncertainty.
    [Show full text]
  • Total Nuclear Photoabsorption Cross Section in the Range 0.2 - 1.0 Gev for Nuclei Throughout the Periodic Table
    IS&N 002ft-sees -CEKTRO BRASILEIRO DE PESOUlSAS FlSlCAS Notas de Ffsica CBPF-NF-059/93 Total Nuclear Photoabsorption Cross Section in the Range 0.2 - 1.0 GeV for Nuclei Throughout the Periodic Table by M.L. Terranova and O.A.P. Tavares di Janeiro 1993 NOTAS DE FlSICA e uma pre-publicac. ao de trabalho original em Fis.ica .» NOTAS DE FlSICA is a preprint of original works un published in Physics * Pedidos de copias desta publicagao devem ser envia. dos aos autores ou a: \ . « Requests for copies of these reports should be addressed to: Centro Brasileiro de Pesquisas Fisicas Xrea de Publicagoes Rua Dr. Xavier Sigaud, 150 - 49 andar 22.290 - Rio de Janeiro, RJ BRASIL ISSN 0029-3865 CBPF'NF'059/93 Total Nuclear Photoabsorption Cross Section in the Range 0.2- 1.0 GeV for Nuclei Throughout the Periodic Table by M.L. Terranova* and O.A.P. Tavares Centro Brasileiro de Pesquisas Fisicas — CBPF/CNPq Rua Dr. Xavier Sigaud, 150 22290-180 - Rio de Janeiro, RJ - Brasil * Dipartimento di Scienze e Tecnoloye Chimiciie, Universita degli Studi di Roma "Tor Vergata" Via della Ricerca Scientifica 1-00133 Roma, Italy and Istituto Nasionale di Fisica Nuclcare - INFN Sezione di Roma 2, Roma, Italy CBPF-NF-059/93 Abstract. An analysis of the total photoabsorption cross section for nuclei ranging from *Ke up to 238u has been performed in the energy range 0.2-1.0 GeV. Kean total photoabsorption cross sections have been obtained by summing up the contributions from partial photoreactior.s, and found to follow an A^-dependence in the 0.2-1.0 GeV range.
    [Show full text]
  • Measurement of Cumulative Photofission Yields of 235U and 238U with a 16 Mev Bremsstrahlung Photon Beam Manon Delarue, E
    Measurement of cumulative photofission yields of 235U and 238U with a 16 MeV Bremsstrahlung photon beam Manon Delarue, E. Simon, B. Pérot, P.G. Allinei, N. Estre, E. Payan, D. Eck, D. Tisseur, Isabelle Espagnon, J. Collot To cite this version: Manon Delarue, E. Simon, B. Pérot, P.G. Allinei, N. Estre, et al.. Measurement of cumulative photofission yields of 235U and 238U with a 16 MeV Bremsstrahlung photon beam. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Elsevier, 2021, 1011, pp.165598. 10.1016/j.nima.2021.165598. cea-03276202 HAL Id: cea-03276202 https://hal-cea.archives-ouvertes.fr/cea-03276202 Submitted on 1 Jul 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Journal Pre-proof Measurement of cumulative photofission yields of 235U and 238U with a 16 MeV Bremsstrahlung photon beam M. Delarue, E. Simon, B. Pérot, P.G. Allinei, N. Estre, E. Payan, D. Eck, D. Tisseur, I. Espagnon, J. Collot PII: S0168-9002(21)00583-0 DOI: https://doi.org/10.1016/j.nima.2021.165598 Reference: NIMA 165598 To appear in: Nuclear Inst.
    [Show full text]
  • PRODUCTION of PHOTOFISSION FRAGMENTS and STUDY of THEIR NUCLEAR STRUCTURE by LASER SPECTROSCOPY Yu
    ¨¸Ó³ ¢ —Ÿ. 2005. ’. 2, º 2(125). ‘. 50Ä59 “„Š 539.183+539.143 PRODUCTION OF PHOTOFISSION FRAGMENTS AND STUDY OF THEIR NUCLEAR STRUCTURE BY LASER SPECTROSCOPY Yu. P. Gangrsky, S. G. Zemlyanoi, D. V. Karaivanov, K. P. Marinova, B. N. Markov, L. M. Melnikova, G. V. Mishinsky, Yu. E. Penionzhkevich, V. I. Zhemenik Joint Institute for Nuclear Research, Dubna The prospective nuclear structure investigations of the ˇssion fragments by resonance laser spec- troscopy methods are discussed. Research in this ˇeld is currently being carried out as part of the DRIBs project, which is under development at the Laboratory of Nuclear Reactions, JINR. The ˇs- sion fragments under study are mainly very neutron-rich nuclei near the proton (Z =50) and neutron (N =50and 82) closed shells, nuclei in the region of strong deformation (N>60 and N>90)and nuclei with high-spin isomeric states. Resonance laser spectroscopy is used successfully in the study of the structure of such nuclei. It allows one to determine a number of nuclear parameters (mean-square charge radius, magnetic dipole and electric quadrupole moments) and to make conclusions about the collective and single-particle properties of the nuclei. ¡¸Ê¦¤ ÕÉ¸Ö ¶¥·¸¶¥±É¨¢Ò ¨¸¸²¥¤µ¢ ´¨Ö ¸É·Ê±ÉÊ·Ò · ¤¨µ ±É¨¢´ÒÌ Ö¤¥· Å ¶·µ¤Ê±Éµ¢ ˵ɵ¤¥- ²¥´¨Ö ³¥Éµ¤ ³¨ ·¥§µ´ ´¸´µ° ² §¥·´µ° ¸¶¥±É·µ¸±µ¶¨¨. ˆ¸¸²¥¤µ¢ ´¨Ö ¢ Ôɵ³ ´ ¶· ¢²¥´¨¨ ¢Ò¶µ²- ´ÖÕÉ¸Ö ¢ · ³± Ì ¶·µ¥±É DRIBs, ·¥ ²¨§Ê¥³µ£µ ¢ ‹ ¡µ· ɵ·¨¨ Ö¤¥·´ÒÌ ·¥ ±Í¨° ˆŸˆ. ˆ¸¸²¥- ¤Ê¥³Ò³¨ ¶·µ¤Ê±É ³¨ ˵ɵ¤¥²¥´¨Ö Ö¢²ÖÕÉ¸Ö ¸¨²Ó´µ ´¥°É·µ´µµ¡µ£ Ð¥´´Ò¥ Ö¤· ¢¡²¨§¨ § ³±´ÊÉÒÌ ¶·µÉµ´´µ° (Z =50) ¨ ´¥°É·µ´´µ° (N =50¨ 82) µ¡µ²µÎ¥±, Ö¤· ¢ µ¡² ¸ÉÖÌ ¸¨²Ó´µ° ¤¥Ëµ·³ ͨ¨ (N>60 ¨ N>90), ¢Ò¸µ±µ¸¶¨´µ¢Ò¥ ¨§µ³¥·Ò.
    [Show full text]
  • Production of Neutron-Rich Nuclei Approaching R-Process by Gamma-Induced fission of 238U at ELI-NP
    EPJ Web of Conferences 178, 04009 (2018) https://doi.org/10.1051/epjconf/201817804009 CGS16 Production of neutron-rich nuclei approaching r-process by gamma-induced fission of 238U at ELI-NP Bo Mei1,2,⋆, Dimiter Balabanski1, Paul Constantin1, Tuan Anh Le1,3, and Phan Viet Cuong1,4 1Extreme Light Infrastructure Nuclear Physics, “Horia Hulubei" National Institute for Physics and Nuclear Engineering, Str. Reactorului 30, 077125 Bucharest Magurele, Romania 2Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China 3Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam 4Centre of Nuclear Physics, Institute of Physics, Vietnam Academy of Science and Technology, Hanoi, Vietnam Abstract. The investigation of neutron-rich exotic nuclei is crucial not only for nuclear physics but also for nuclear astrophysics. Experimentally, only few neutron-rich nuclei near the stability have been studied, however, most neutron-rich nuclei have not been measured due to their small production cross sections as well as short half-lives. At ELI-NP, gamma beams with high intensities will open new opportunities to investigate very neutron-rich fragments produced by photofission of 238U targets in a gas cell. Based on some simulations, a novel gas cell has been designed to produce, stop and extract 238U photofission fragments. The extraction time and efficiency of photofission fragments have been optimized by using SIMION simulations. According to these simulations, a high extraction efficiency and a short extraction time can be achieved for 238U photofission fragments in the gas cell, which will allow one to measure very neutron-rich fragments with short half-lives by using the IGISOL facility proposed at ELI-NP.
    [Show full text]
  • ENERGY DEPENDENT PROMPT NEUTRON MULTIPLICITY PARAMETERIZATION for ACTINIDE PHOTOFISSION A.I. Lengyel , O.O. Parlag , I.V. Pylyp
    ENERGY DEPENDENT PROMPT NEUTRON MULTIPLICITY PARAMETERIZATION FOR ACTINIDE PHOTOFISSION A.I. Lengyel 1, O.O. Parlag 1, I.V. Pylypchynec 1, V.T. Maslyuk 1, M.I. Romanyuk 1, O.O. Gritzay 2 1) Institute of Electron Physics Universitetska 21, Uzhgorod 88017 Ukraine, [email protected] 2) Institute for Nuclear Research Prospekt Nauky 47, Kyiv 03028 Ukraine The prompt neutron averaged number ν and the dependence of prompt neutron yield on fragment mass ν(A) of photofission of actinide nuclei 235 U and 238 U in the giant dipole resonance energy range has been parameterized. This allows us to describe the observed changes of saw-tooth behavior of neutron yield from the light and heavy fragments using few energy and nucleon composition dependent free parameters and to predict ν(A) for other actinide isotopes. Keywords : prompt neutrons, average number of prompt neutrons, photofission, actinides PACS: 24.75.+1, 25.85.-w, 25.85. Ec, 25.85. Ca 1. INTRODUCTION The number of prompt neutrons is important nuclear-physical parameter necessary for practical calculations. This value is determined in detail and accurately for neutron-induced reactions for the most nuclides. At the same time, the experimental data and evaluation of prompt neutron yield in the case of photofission are much scarcer. With the increasing interest in the methods of nuclear fuel burning and long-lived actinide decontamination the need in precise values of nuclear constants is evident during last years [1-6]. This is especially true for photonuclear constants. Therefore, the search was focused on a formulas that can be used to estimate the value of average number ν (A F), AF – mass of fissioning nuclide, and number of neutrons ν(A) , emitted by corresponding fission fragments of atomic mass for photofission of arbitrary actinide [7].
    [Show full text]