Showing papers by "L. Tassan-Got published in 2015"
CERN1, Technical University of Lisbon2, French Alternative Energies and Atomic Energy Commission3, University of Seville4, Centre national de la recherche scientifique5, Vienna University of Technology6, Istituto Nazionale di Fisica Nucleare7, Goethe University Frankfurt8, Charles University in Prague9, University of Manchester10, University of Zagreb11, University of Santiago de Compostela12, Polytechnic University of Catalonia13, Bhabha Atomic Research Centre14, National Technical University of Athens15, Spanish National Research Council16, Paul Scherrer Institute17, Joint Institute for Nuclear Research18, Japan Atomic Energy Agency19, University of York20, Karlsruhe Institute of Technology21, Tokyo Institute of Technology22, University of Edinburgh23, University of Bologna24, ENEA25, German National Metrology Institute26, University of Ioannina27, University of Vienna28, University of Hertfordshire29, Australian National University30
01 Nov 2015-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: The design of the beam line and the experimental hall was based on FLUKA Monte Carlo simulations, aiming at maximizing the neutron flux, reducing the beam halo and minimizing the background from neutrons interacting with the collimator or backscattered in the beam dump as discussed by the authors.
Abstract: At the neutron time-of-flight facility n_TOF at CERN a new vertical beam line was constructed in 2014, in order to extend the experimental possibilities at this facility to an even wider range of challenging cross-section measurements of interest in astrophysics, nuclear technology and medical physics. The design of the beam line and the experimental hall was based on FLUKA Monte Carlo simulations, aiming at maximizing the neutron flux, reducing the beam halo and minimizing the background from neutrons interacting with the collimator or back-scattered in the beam dump.
The present paper gives an overview on the design of the beam line and the relevant elements and provides an outlook on the expected performance regarding the neutron beam intensity, shape and energy resolution, as well as the neutron and photon backgrounds.
94 citations
TL;DR: In this paper, the authors measured residual fragment production in spallation reactions induced by a liquid deuterium target at 500A$ MeV and showed that the energy dissipated in these reactions was assessed by comparing the production yields measured in this work with the ones obtained in reaction induced by $^{136}mathrm{Xe}$ projectiles on protons at $1000A$ and $500A$ MEV.
Abstract: Residual fragment production in reactions induced by $^{136}\mathrm{Xe}$ projectiles impinging on a liquid deuterium target at $500A$ MeV has been measured at GSI. Projectile residues were unambiguously identified in atomic and mass numbers using the Fragment Separator as high-resolution zero-degree spectrometer. The isotopic production yields of these residuals were used to benchmark reference model calculations describing spallation reactions. In particular the energy dissipated in these reactions was assessed by comparing the production yields measured in this work with the ones obtained in reactions induced by $^{136}\mathrm{Xe}$ projectiles on protons at $1000A$ and $500A$ MeV.
26 citations
TL;DR: In this article, the U238 to U235 fission cross section ratio has been determined at n_TOF up to ˜1 GeV, with two different detection systems, in different geometrical configurations.
Abstract: The U238 to U235 fission cross section ratio has been determined at n_TOF up to ˜1 GeV, with two different detection systems, in different geometrical configurations. A total of four datasets has been collected and compared. They are all consistent to each other within the relative systematic uncertainty of 3–4%. The data collected at n_TOF have been suitably combined to yield a unique fission cross section ratio as a function of neutron energy. The result confirms current evaluations up to 200 MeV. Good agreement is also observed with theoretical calculations based on the INCL++/Gemini++ combination up to the highest measured energy. The n_TOF results may help solve a long-standing discrepancy between the two most important experimental datasets available so far above 20 MeV, while extending the neutron energy range for the first time up to ˜1 GeV.
24 citations
TL;DR: A review of the most important results on fission cross-sections and fragment properties obtained at n_TOF for a variety of (radioactive) isotopes is presented along with the perspectives arising from the coming on line in the second half of 2014 of a new 19 m flight-path, which will allow n_toF to expand its measurement capabilities to even more rare or short-lived isotopes, such as 230 Th, 232 U, 238,240 Pu and 244 Cm as mentioned in this paper.
9 citations
TL;DR: The first SOFIA experiment (Studies On FIssion with Aladin) was performed in August 2012 at GSI, where the fission of several neutron-deficient actinides and pre-actinides was induced in flight at 700 A MeV by electromagnetic excitation.
4 citations
TL;DR: In this article, the U 238 to U 235 fission cross section ratio has been determined at n_TOF up to ≈1 GeV, with two different detection systems, in different geometrical configurations.
Abstract: The U 238 to U 235 fission cross section ratio has been determined at n_TOF up to ≈1 GeV, with two different detection systems, in different geometrical configurations. A total of four datasets has been collected and compared. They are all consistent to each other within the relative systematic uncertainty of 3–4%. The data collected at n_TOF have been suitably combined to yield a unique fission cross section ratio as a function of neutron energy. The result confirms current evaluations up to 200 MeV. Good agreement is also observed with theoretical calculations based on the INCL++/ Gemini++ combination up to the highest measured energy. The n_TOF results may help solve a long-standing discrepancy between the two most important experimental datasets available so far above 20 MeV, while extending the neutron energy range for the first time up to ≈1 GeV.
1 citations
TL;DR: In this paper, a complete kinematic measurement of 208Pb was performed at GSI Darmstadt where the combined use of the inverse kinematics technique with an efficient detection setup allowed to measure for the first time the atomic and mass number of both fission fragments.
1 citations
01 Jan 2015
TL;DR: In this article, the authors present an overview of the experimental nuclear data activities at CERN's neutron time-of-flight facility n_TOF, which has produced a considerable amount of experimental data since it became fully operational with the start of its scientific measurement programme in 2002.
Abstract: Applications of nuclear data like neutron-induced reaction cross sections are related to research fields as stellar nucleosynthesis, the study of nuclear level densities and strength functions, and also play a key role in the safety and criticality assessment of existing and future nuclear reactors, in areas concerning radiation dosimetry, medical applications, transmutation of nuclear waste, accelerator-driven systems and fuel cycle investigations. The evaluations in nuclear data 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 2002. 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 CERN’s neutron time-of-flight facility n_TOF will be presented.
1 citations
University of Zagreb1, Istituto Nazionale di Fisica Nucleare2, Goethe University Frankfurt3, Centre national de la recherche scientifique4, Charles University in Prague5, French Alternative Energies and Atomic Energy Commission6, CERN7, University of Manchester8, Polytechnic University of Catalonia9, Technical University of Lisbon10, University of Seville11, National Technical University of Athens12, Spanish National Research Council13, Paul Scherrer Institute14, University of Santiago de Compostela15, Aristotle University of Thessaloniki16, Bhabha Atomic Research Centre17, Vienna University of Technology18, University of York19, Karlsruhe Institute of Technology20, University of Oslo21, University of Vienna22, ENEA23, University of Bologna24, University of Basel25
TL;DR: In this paper, the authors measured the capture cross section of 58 Ni at the neutron time of flight facility n_TOF at CERN, from 27 meV to 400 keV neutron energy.
Abstract: The neutron capture cross section of 58 Ni was measured at the neutron time of flight facility n_TOF at CERN, from 27 meV to 400 keV neutron energy. Special care has been taken to identify all the possible sources of background, with the so-called neutron background obtained for the first time using high-precision GEANT4 simulations. The energy range up to 122 keV was treated as the resolved resonance region, where 51 resonances were identified and analyzed by a multilevel R -matrix code SAMMY. Above 122 keV the code SESH was used in analyzing the unresolved resonance region of the capture yield. Maxwellian averaged cross sections were calculated in the temperature range of kT = 5 – 100 keV, and their astrophysical implications were investigated.