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1.
  • Alcayne, V., et al. (författare)
  • A segmented total energy detector (sTED) for (n, gamma) cross section measurements at n_TOF EAR2
  • 2023
  • Ingår i: 15TH INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY, ND2022. - : EDP Sciences.
  • Konferensbidrag (refereegranskat)abstract
    • The neutron time-of-flight facility n_TOF is characterised by its high instantaneous neutron intensity, high resolution and broad neutron energy spectra, specially conceived for neutron-induced reaction cross section measurements. Two Time-Of-Flight (TOR) experimental areas are available at the facility: experimental area 1 (EAR1), located at the end of the 185 m horizontal flight path from the spallation target, and experimental area 2 (EAR2), placed at 20 m from the target in the vertical direction. The neutron fluence in EAR2 is similar to 300 times more intense than in EARL in the relevant time-of-flight window. EAR2 was designed to carry out challenging cross-section measurements with low mass samples (approximately 1 mg), reactions with small cross-sections or/and highly radioactive samples. The high instantaneous fluence of EAR2 results in high counting rates that challenge the existing capture systems. Therefore, the sTED detector has been designed to mitigate these effects. In 2021, a dedicated campaign was done validating the performance of the detector up to at least 300 keV neutron energy. After this campaign, the detector has been used to perform various capture cross section measurements at n_TOF EAR2.
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2.
  • Stamati, M. E., et al. (författare)
  • The n_TOF NEAR Station Commissioning and first physics case
  • 2023
  • Ingår i: 15TH INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY, ND2022. - : EDP Sciences.
  • Konferensbidrag (refereegranskat)abstract
    • The NEAR Station is a new experimental area developed at the n_TOF Facility at CERN. The activation station of NEAR underwent a characterization of the beam following the installation of the new n_TOF Spallation Target. The commissioning of the neutron beam comprises a set of simulations made with the FLUKA code and experimental verification. The experimental determination of the neutron spectrum was made using activation techniques with three separate set-ups. Two set-ups were based on the Multi-foil Activation technique (MAM-1 and MAM-2), and the third set-up relied on the process of neutron moderation and activation of a single material (ANTILoPE). The three set-ups are presented. Also the present plans and future perspectives of the activation station of NEAR are discussed.
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3.
  • Tagliente, G., et al. (författare)
  • The n_TOF facility at CERN
  • 2024
  • Ingår i: 16<sup>th</sup> Varenna Conference on Nuclear Reaction Mechanisms (NRM2023). - : EDP Sciences. - 9782759891245
  • Konferensbidrag (refereegranskat)abstract
    • The neutron Time-of-Flight facility (n_TOF) is an innovative facility operative since 2001 at CERN, with three experimental areas. In this paper the n_TOF facility will be described, together with the upgrade of the facility during the Long Shutdown 2 at CERN. The main features of the detectors used for capture fission cross section measurements will be presented with perspectives for the future measurements.
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4.
  • Garcia-Infantes, F., et al. (författare)
  • First high resolution measurement of neutron capture resonances in Yb-176 at the n_TOF CERN facility.
  • 2023
  • Ingår i: 15TH INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY, ND2022. - : EDP Sciences.
  • Konferensbidrag (refereegranskat)abstract
    • Several international agencies recommend the study of new routes and new facilities for producing radioisotopes with application to nuclear medicine. Lu-177 is a versatile radioisotope used for therapy and diagnosis (theranostics) of cancer with good success in neuroendocrine tumours that is being studied to be applied to a wider range of tumours. Lu-177 is produced in few nuclear reactors mainly by the neutron capture on Lu-176. However, it could be produced at high -intensity accelerator-based neutron facilities. The energy of the neutrons in accelerator-based neutron facilities is higher than in thermal reactors. Thus, experimental data on the Yb-176(n,(sic)) cross-section in the eV and keV region are mandatory to calculate accurately the production of Yb-177, which beta decays to 177Lu. At present, there are not experimental data available from thermal to 3 keV of the Yb-176(n,(sic)) cross-section. In addition, there is no data in the resolved resonance region (RRR). This contribution shows the first results of the Yb-176 capture measurement performed at the n_TOF facility at CERN.
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5.
  • Mucciola, R., et al. (författare)
  • Neutron capture and total cross-section measurements on Mo-94'95'96 at n_TOF and GELINA
  • 2023
  • Ingår i: 15th International Conference on Nuclear Data for Science and Technology, ND2022. - : EDP Sciences.
  • Konferensbidrag (refereegranskat)abstract
    • Capture and total cross section measurements for 94'95'96 MO have been performed at the neutron time -of-flight facilities, n_TOF at CERN and GELINA at JRC-Geel. The measurements were performed using isotopically enriched samples with an enrichment above 95% for each of the (94'95'96)M0 isotopes. The capture measurements were performed at n_TOF using C6D6 detectors and a new sTED detector. The transmission measurements were performed at a 10 m station of GELINA using a Li-6 glass neutron detector. Preliminary results of these measurements are presented.
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6.
  • Pavon-Rodriguez, J. A., et al. (författare)
  • Characterisation of the n_TOF 20 m beam line at CERN with the new spallation target
  • 2023
  • Ingår i: 15TH INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY, ND2022. - : EDP Sciences.
  • Konferensbidrag (refereegranskat)abstract
    • The n_TOF facility hosts CERN's pulsed neutron source, comprising two beam lines of different flight paths and one activation station. It is based on a proton beam delivered by the PS accelerator impinging on a lead spallation target. During Long Shutdown 2 (LS2) at CERN (2019-2021), a major upgrade of the spallation target was carried out in order to optimize the performances of the neutron beam. Therefore, the characteristics of n_TOF two experimental areas were investigated in detail. In this work, the focus is on the second experimental area (EAR2), located 20 m above the spallation target. Preliminary results of the neutron energy distribution and beam line energy resolution are presented, compared to previous experimental campaigns and Monte Carlo simulations with the FLUKA code. Moreover, preliminary results of the spatial beam profile measurements are shown.
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7.
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8.
  • Alcayne, V., et al. (författare)
  • A Segmented Total Energy Detector (sTED) optimized for (n,ϒ) cross-section measurements at n_TOF EAR2
  • 2024
  • Ingår i: Radiation Physics and Chemistry. - : Elsevier. - 0969-806X .- 1879-0895. ; 217
  • Tidskriftsartikel (refereegranskat)abstract
    • The neutron time-of-flight facility n_TOF at CERN is a spallation source dedicated to measurements of neutroninduced reaction cross-sections of interest in nuclear technologies, astrophysics, and other applications. Since 2014, Experimental ARea 2 (EAR2) is operational and delivers a neutron fluence of similar to 4 center dot 10(7) neutrons per nominal proton pulse, which is similar to 50 times higher than the one of Experimental ARea 1 (EAR1) of similar to 8 center dot 10(5) neutrons per pulse. The high neutron flux at EAR2 results in high counting rates in the detectors that challenged the previously existing capture detection systems. For this reason, a Segmented Total Energy Detector (sTED) has been developed to overcome the limitations in the detector's response, by reducing the active volume per module and by using a photo-multiplier (PMT) optimized for high counting rates. This paper presents the main characteristics of the sTED, including energy and time resolution, response to gamma-rays, and provides as well details of the use of the Pulse Height Weighting Technique (PHWT) with this detector. The sTED has been validated to perform neutron-capture cross-section measurements in EAR2 in the neutron energy range from thermal up to at least 400 keV. The detector has already been successfully used in several measurements at n_TOF EAR2.
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9.
  • Diakaki, M., et al. (författare)
  • Towards the high-accuracy determination of the 238U fission cross section at the threshold region at CERN -€“ n_TOF
  • 2016
  • Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X.
  • Konferensbidrag (refereegranskat)abstract
    • The U-238 fission cross section is an international standard beyond 2 MeV where the fission plateau starts. However, due to its importance in fission reactors, this cross-section should be very accurately known also in the threshold region below 2 MeV. The U-238 fission cross section has been measured relative to the U-235 fission cross section at CERN - n_TOF with different detection systems. These datasets have been collected and suitably combined to increase the counting statistics in the threshold region from about 300 keV up to 3 MeV. The results are compared with other experimental data, evaluated libraries, and the IAEA standards.
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10.
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11.
  • Massimi, C., et al. (författare)
  • Neutron-induced cross section measurements
  • 2023
  • Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X. ; 279
  • Tidskriftsartikel (refereegranskat)abstract
    • Neutron-induced cross sections represent the main nuclear input to models of stellar and Big-Bang nucleosynthesis. While (n,γ) reactions are relevant for the formation of elements heavier than iron, (n,p) and (n,α) reactions can play an important role in specific cases. The time-of-flight method is routinely used at n_TOF to experimentally determine the cross section data. In addition, recent upgrades of the facility will allow the use of activation techniques as well, possibly opening the way to a systematic study of neutron interaction with radioactive isotopes. In the last 20 years n_TOF has provided a large amount of experimental data for Nuclear Astrophysics. Our plan is to carry on challenging measurements and produce nuclear data in the next decades as well.
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12.
  • Paradela, C., et al. (författare)
  • High-accuracy determination of the 238U/235U fission cross section ratio up to ~1 GeV at n_TOF at CERN
  • 2015
  • Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 91, s. 024602-
  • Tidskriftsartikel (refereegranskat)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.
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13.
  • Patronis, N., et al. (författare)
  • Status report of the n_TOF facility after the 2nd CERN long shutdown period
  • 2023
  • Ingår i: EPJ TECHNIQUES AND INSTRUMENTATION. - : Springer Nature. - 2195-7045. ; 10
  • Tidskriftsartikel (refereegranskat)abstract
    • During the second long shutdown period of the CERN accelerator complex (LS2, 2019-2021), several upgrade activities took place at the n_TOF facility. The most important have been the replacement of the spallation target with a next generation nitrogen-cooled lead target. Additionally, a new experimental area, at a very short distance from the target assembly (the NEAR Station) was established. In this paper, the core commissioning actions of the new installations are described. The improvement in the n_TOF infrastructure was accompanied by several detector development projects. All these upgrade actions are discussed, focusing mostly on the future perspectives of the n_TOF facility. Furthermore, some indicative current and future measurements are briefly reported.
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14.
  • Balibrea-Correa, J., et al. (författare)
  • First measurement of the 94Nb(n,γ) cross section at the CERN n_TOF facility
  • 2023
  • Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X. ; 279
  • Tidskriftsartikel (refereegranskat)abstract
    • One of the crucial ingredients for the improvement of stellar models is the accurate knowledge of neutron capture cross-sections for the different isotopes involved in the s-,r- and i- processes. These measurements can shed light on existing discrepancies between observed and predicted isotopic abundances and help to constrain the physical conditions where these reactions take place along different stages of stellar evolution.In the particular case of the radioactive 94Nb, the 94Nb(n,γ) cross-section could play a role in the determination of the s-process production of 94Mo in AGB stars, which presently cannot be reproduced by state-of-the-art stellar models. There are no previous 94Nb(n,γ) experimental data for the resolved and unresolved resonance regions mainly due to the difficulties in producing highquality samples and also due to limitations in conventional detection systems commonly used in time-of-flight experiments.Motivated by this situation, a first measurement of the 94Nb(n,γ) reaction was carried out at CERN n_TOF, thereby exploiting the high luminosity of the EAR2 area in combination with a new detection system of small-volume C6D6-detectors and a high quality 94Nb-sample. The latter was based on hyper-pure 93Nb material activated at the high-flux reactor of ILL-Grenoble. An innovative ring-configuration detection system in close geometry around the capture sample allowed us to significantly enhance the signal-to-background ratio. This set-up was supplemented with two conventional C6D6-detectors and a highresolution LaCl3(Ce)-detector, which will be employed for addressing reliably systematic effects and uncertainties.At the current status of the data analysis, 18 resonance in 94Nb+n have been observed for the first time in the neutron energy range from thermal up to 10 keV.
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15.
  • Domingo-Pardo, C., et al. (författare)
  • Advances and new ideas for neutron-capture astrophysics experiments at CERN n_TOF
  • 2023
  • Ingår i: European Physical Journal A. - : Springer. - 1434-6001 .- 1434-601X. ; 59:1
  • Tidskriftsartikel (refereegranskat)abstract
    • This article presents a few selected developments and future ideas related to the measurement of (n,γ) data of astrophysical interest at CERN n_TOF. The MC-aided analysis methodology for the use of low-efficiency radiation detectors in time-of-flight neutron-capture measurements is discussed, with particular emphasis on the systematic accuracy. Several recent instrumental advances are also presented, such as the development of total-energy detectors with γ-ray imaging capability for background suppression, and the development of an array of small-volume organic scintillators aimed at exploiting the high instantaneous neutron-flux of EAR2. Finally, astrophysics prospects related to the intermediate i neutron-capture process of nucleosynthesis are discussed in the context of the new NEAR activation area.
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16.
  • Domingo-Pardo, C., et al. (författare)
  • Compton imaging for enhanced sensitivity (n,gamma) cross section TOF experiments : Status and prospects
  • 2023
  • Ingår i: 15TH INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY, ND2022. - : EDP Sciences.
  • Konferensbidrag (refereegranskat)abstract
    • Radiative neutron-capture cross sections are of pivotal importance in many fields such as nucle-osynthesis studies or innovative reactor technologies. A large number of isotopes have been measured with high accuracy, but there are still a large number of relevant isotopes whose cross sections could not be experimentally determined yet, at least with sufficient accuracy and completeness, owing to limitations in detection techniques, sample production methods or in the facilities themselves. In the context of the HYMNS (High-sensitivitY Measurements of key stellar Nucleo-Synthesis reactions) project over the last six years we have developed a novel detection technique aimed at background suppression in radiative neutron-capture time-of-flight measurements. This new technique utilizes a complex detection set-up based on position-sensitive radiation-detectors deployed in a Compton-camera array configuration. The latter enables to implement gamma-ray imaging techniques, which help to disentangle true capture events arising from the sample under study and contaminant background events from the surroundings. A summary on the main developments is given in this contribution together with an update on recent experiments at CERN n_TOF and an outlook on future steps.
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17.
  • Domingo-Pardo, C., et al. (författare)
  • The neutron time-of-flight facility n_TOF at CERN Recent facility upgrades and detector developments
  • 2023
  • Ingår i: Journal of Physics, Conference Series. - : Institute of Physics (IOP). - 1742-6588 .- 1742-6596. ; 2586
  • Tidskriftsartikel (refereegranskat)abstract
    • Based on an idea by Carlo Rubbia, the n_TOF facility at CERN has been operating for over 20 years. It is a neutron spallation source, driven by the 20 GeV/c proton beam from the CERN PS accelerator. Neutrons in a very wide energy range (from GeV, down to sub-eV kinetic energy) are generated by a massive Lead spallation target feeding two experimental areas. EAR1, horizonal with respect to the proton beam direction is set at 185 meters from the spallation target. EAR2, on the vertical line from the spallation source, is placed at 20 m. Neutron energies for experiments are selected by the time-of-flight technique (hence the name n_TOF), while the long flight paths ensure a very good energy resolution. Over one hundred experiments have been performed by the n_TOF Collaboration at CERN, with applications ranging from nuclear astrophysics (synthesis of the heavy elements in stars, big bang nucleosynthesis, nuclear cosmo-chronology), to advanced nuclear technologies (nuclear data for applications, nuclear safety), as well as for basic nuclear science (reaction mechanisms, structure and decay of highly excited compound states). During the planned shutdown of the CERN accelerator complex between 2019 and 2021, the facility went through a substantial upgrade with a new target-moderator assembly, refurbishing of the neutron beam lines and experimental areas. An additional measuring and irradiation station (the NEAR Station) has been envisaged and its capabilities for performing material test studies and new physics opportunities are presently explored. An overview of the facility and of the activities performed at CERN is presented in this contribution, with a particular emphasis on the most relevant experiments for nuclear astrophysics.
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18.
  • Dupont, E., et al. (författare)
  • Overview of the dissemination of n_TOF experimental data and resonance parameters
  • 2023
  • Ingår i: 15TH INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY, ND2022. - : EDP Sciences.
  • Konferensbidrag (refereegranskat)abstract
    • The n_TOF neutron time-of-flight facility at CERN is used for nuclear data measurements. The n_TOF Collaboration works closely with the Nuclear Reaction Data Centres (NRDC) network to disseminate the experimental data through the international EXFOR library. In addition, the Collaboration helps integrate the results in the evaluated library projects. The present contribution describes the dissemination status of n_TOF results, their impact on evaluated libraries and ongoing efforts to provide n_TOF resonance parameters in ENDF-6 format for further use by evaluation projects.
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19.
  • Hashimoto, T., et al. (författare)
  • Beamline test of a transition-edge-sensor spectrometer in preparation for kaonic-atom measurements
  • 2017
  • Ingår i: IEEE Transactions on Applied Superconductivity. - 1051-8223. ; 27:4
  • Tidskriftsartikel (refereegranskat)abstract
    • We are developing a new technique to apply transition-edge sensors (TESs) to X-ray spectroscopy of exotic atoms, especially of kaonic atoms. To demonstrate the feasibility of this pioneering project, performance of a TES-based X-ray detector was evaluated in pion- and kaon-beam environments at particle accelerators.We successfully observed X-rays from pionic-carbon atoms with a resolution as good as 7 eV FWHM at 6 keV. Also at a kaon beamline, we confirmed that the TES spectrometer will be able to achieve our resolution goal, 6 eV, in our first scientific campaign to measure X-rays from kaonic-helium atoms.
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20.
  • Hashimoto, T., et al. (författare)
  • Kaonic-Atom X-ray Spectroscopy with Superconducting Microcalorimeters
  • 2017
  • Ingår i: Proceedings of the 12th International Conference on Hypernuclear and Strange Particle Physics (HYP2015). - 9784890271221 ; 17
  • Konferensbidrag (refereegranskat)abstract
    • We will measure kaonic helium X-rays using transition-edge-sensor microcalorimeters, TES, in the J-PARC hadron experimental facility. To demonstrate the feasibility of the experiment, we performed a measurement of pionic carbon X-rays at PSI, where an excellent FWHM energy resolution of 7 eV at 6.4 keV was achieved. We also evaluated the expected TES performance in the kaon beam at J-PARC. The simulation results show that the TES spectrometer would work with a good energy resolution, and clear peaks of kaonic helium X-rays would be observed on a reasonably suppressed background.
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21.
  • Lerendegui-Marco, J., et al. (författare)
  • New detection systems for an enhanced sensitivity in key stellar (n,γ) measurements
  • 2023
  • Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X. ; 279
  • Tidskriftsartikel (refereegranskat)abstract
    • Neutron capture cross-section measurements are fundamental in the study of astrophysical phenomena, such as the slow neutron capture (s-) process of nucleosynthesis operating in red-giant and massive stars. However, neutron capture measurements via the time-of-flight (TOF) technique on key s-process nuclei are often challenging. Difficulties arise from the limited mass (∼mg) available and the high sample-related background in the case of the unstable s-process branching points. Measurements on neutron magic nuclei, that act as s-process bottlenecks, are affected by low (n,γ) cross sections and a dominant neutron scattering background. Overcoming these experimental challenges requires the combination of facilities with high instantaneous flux, such as n_TOFEAR2, with detection systems with an enhanced detection sensitivity and high counting rate capabilities. This contribution reviews some of the latest detector developments in detection systems for (n,γ) measurements at n_TOF, such as i-TED, an innovative detection system which exploits the Compton imaging technique to reduce the dominant neutron scattering background and s-TED, a highly segmented total energy detector intended for high flux facilities. The discussion will be illustrated with results of the first measurement of key the s-process branching-point reaction 79Se(n,γ).
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22.
  • Lerendegui-Marco, J., et al. (författare)
  • New perspectives for neutron capture measurements in the upgraded CERN-n_TOF Facility
  • 2023
  • Ingår i: 15th International Conference on Nuclear Data for Science and Technology, ND2022. - : EDP Sciences.
  • Konferensbidrag (refereegranskat)abstract
    • The n_TOF facility has just undergone in 2021 a major upgrade with the installation of its third generation spallation target that has been designed to optimize the performance of the two n_TOF time-of-flight lines. This contribution describes the key features and limitations for capture measurements in the two beam lines prior to the target upgrade and presents first results of (n,gamma) measurements carried out as part of the commissioning of the upgraded facility. In particular, the energy resolution, a key factor for both increasing the signal-to background ratio and obtaining accurate resonance parameters, has been clearly improved for the 20 m long vertical beam-line with the new target design while keeping the remarkably high resolution of the long beamline n_TOF-EAR1. The improvements in the n_TOF neutron beam-lines need to be accompanied by improvements in the instrumentation. A review is given on recent detector R&D projects aimed at tackling the existing challenges and further improving the capabilities of this facility.
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23.
  • Mastromarco, M., et al. (författare)
  • Measurement of the Gd-160(n, gamma) cross section at n_TOF and its medical implications
  • 2023
  • Ingår i: 15TH INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY, ND2022. - : EDP Sciences.
  • Konferensbidrag (refereegranskat)abstract
    • Neutron-capture reactions on gadolinium isotopes play an important role in several fields of physics, in particular in nuclear Astrophysics for the understanding of the nucleosynthesis of heavy elements (beyond iron) in stars via the s- and r-processes [1] and in nuclear technology. Another important application of gadolinium is linked to the production of terbium, that offers a set of clinically interesting isotopes for theranostics, characterized by complementary physical decay characteristics. In particular, the low -energy beta(-) emitter terbium-161 is very similar to lutetium-177 in terms of half-life (6.89 d), beta(-) - energy and chemical properties. Being a significant emitter of conversion/Auger electrons, greater therapeutic effect can therefore be expected in comparison to Lu-177 [2, 3]. For this reason, in the last decade, the study of the neutron capture reaction Gd-160(n,,gamma)(161) Gd and the subsequent beta(-) - decay in terbium-161 is getting particular attention. As the nuclear data on the Gd-160 neutron capture reaction are quite scarce and inconsistent, a new measurement of the capture cross section of Gd-160 at the CERN neutron Time -Of-Flight facilty was performed in order to provide high resolution, high -accuracy data on this important reaction, in the energy range from thermal to hundreds of keV. In this contribution, the preliminary results of the n_TOF measurement are presented.
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24.
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25.
  • Leal-Cidoncha, E., et al. (författare)
  • Fission Fragment Angular Distribution measurements of 235U and 238U at CERN n_TOF facility
  • 2016
  • Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X.
  • Konferensbidrag (refereegranskat)abstract
    • Neutron-induced fission cross sections of U-238 and U-235 are used as standards in the fast neutron region up to 200 MeV. A high accuracy of the standards is relevant to experimentally determine other neutron reaction cross sections. Therefore, the detection efficiency should be corrected by using the angular distribution of the fission fragments (FFAD), which are barely known above 20 MeV. In addition, the angular distribution of the fragments produced in the fission of highly excited and deformed nuclei is an important observable to investigate the nuclear fission process. In order to measure the FFAD of neutron-induced reactions, a fission detection setup based on parallel-plate avalanche counters (PPACs) has been developed and successfully used at the CERN-n_TOF facility. In this work, we present the preliminary results on the analysis of new U-235(n,f) and U-238(n,f) data in the extended energy range up to 200 MeV compared to the existing experimental data.
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26.
  • Leal-Cidoncha, E., et al. (författare)
  • High accuracy 234U(n,f) cross section in the resonance energy region
  • 2017
  • Ingår i: ND 2016. - Les Ulis : EDP Sciences. - 9782759890200
  • Konferensbidrag (refereegranskat)abstract
    • New results are presented of the 234U neutron-induced fission cross section, obtained with high accuracy in the resonance region by means of two methods using the 235U(n,f) as reference. The recent evaluation of the 235U(n,f) obtained with SAMMY by L. C. Leal et al. (these Proceedings), based on previous n_TOF data [1], has been used to calculate the 234U(n,f) cross section through the 234U/235U ratio, being here compared with the results obtained by using the n_TOF neutron flux.
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27.
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28.
  • Praena, J., et al. (författare)
  • Preparation and characterization of 33S samples for 33S(n,alpha)30Si cross-section measurements at the n_TOF facility at CERN
  • 2018
  • Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 890, s. 142-147
  • Tidskriftsartikel (refereegranskat)abstract
    • Thin 33S samples for the study of the 33S(n,alpha)30Si cross-section at the n_TOF facility at CERN were made by thermal evaporation of 33S powder onto a dedicated substrate made of kapton covered with thin layers of copper, chromium and titanium. This method has provided for the first time bare sulfur samples a few centimeters in diameter. The samples have shown an excellent adherence with no mass loss after few years and no sublimation in vacuum at room temperature. The determination of the mass thickness of 33S has been performed by means of Rutherford backscattering spectrometry. The samples have been successfully tested under neutron irradiation.
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29.
  • Tarrío, Diego, et al. (författare)
  • Fission Fragment Angular Distribution of Th-232(n,f) at the CERN n_TOF Facility
  • 2014
  • Ingår i: Nuclear Data Sheets. - Univ Santiago de Compostela, Santiago De Compostela, Spain. [Leong, L. S.; Audouin, L.; Tassan-Got, L.; Lederer, C.] IPN, CNRS, IN2P3, Orsay, France. [Altstadt, S.; Langer, C.; Lederer, C.; Reifarth, R.; Schmidt, S.; Weigand, M.] Goethe Univ Frankfurt, D-60054 Frankfurt, Germany. [Andrzejewski, J.; Marganiec, J.; Perkowski, J.] Univ Lodz, PL-90131 Lodz, Poland. [Barbagallo, M.; Colonna, N.; Mastromarco, M.; Meaze, M.; Tagliente, G.; Variale, V.] Ist Nazl Fis Nucl, I-70126 Bari, Italy. [Becares, V.; Cano-Ott, D.; Garcia, A. R.; Gonzalez-Romero, E.; Martinez, T.; Mendoza, E.] CIEMAT, E-28040 Madrid, Spain. [Becvar, F.; Krticka, M.; Kroll, J.; Valenta, S.] Charles Univ Prague, Prague, Czech Republic. [Belloni, F.; Berthoumieux, E.; Bosnar, D.; Chiaveri, E.; Fraval, K.; Gunsing, F.] CEA Saclay, Irfu, F-91191 Gif Sur Yvette, France. [Berthoumieux, E.; Boccone, V.; Bosnar, D.; Brugger, M.; Calviani, M.; Cerutti, F.; Chiaveri, E.; Chin, M.; Ferrari, A.; Guerrero, C.; Kadi, Y.; Losito, R.; Roman, F.; Rubbia, C.; Tsinganis, A.; Versaci, R.; Vlachoudis, V.] CERN, European Org Nucl Res, CH-1211 Geneva, Switzerland. [Billowes, J.; Ware, T.; Wright, T. J.] Univ Manchester, Manchester, Lancs, England. [Zugec, P.] Univ Zagreb, Fac Sci, Dept Phys, Zagreb 41000, Croatia. [Calvino, F.; Cortes, G.; Gomez-Hornillos, M. B.; Riego, A.] Univ Politecn Cataluna, Barcelona, Spain. [Carrapico, C.; Goncalves, I. F.; Sarmento, R.; Vaz, P.] Univ Tecn Lisboa, Inst Super Tecn, Inst Tecnol Nucl, P-1096 Lisbon, Portugal. [Cortes-Giraldo, M. A.; Praena, J.; Quesada, J. M.] Univ Seville, Seville, Spain. [Diakaki, M.; Karadimos, D.; Kokkoris, M.; Vlastou, R.] Natl Tech Univ Athens, GR-10682 Athens, Greece. [Domingo-Pardo, C.; Giubrone, G.; Tain, J. L.] Univ Valencia, CSIC, Inst Fis Corpuscular, E-46003 Valencia, Spain. [Dzysiuk, N.; Mastinu, P. F.] Ist Nazl Fis Nucl, Lab Nazl Legnaro, Milan, Italy. [Eleftheriadis, C.; Manousos, A.] Aristotle Univ Thessaloniki, GR-54006 Thessaloniki, Greece. [Ganesan, S.; Gurusamy, P.] Bhabha Atom Res Ctr, Bombay 400085, Maharashtra, India. [Griesmayer, E.; Jericha, E.; Leeb, H.; Weiss, C.] Vienna Univ Technol, Inst Atom, Vienna, Austria. [Jenkins, D. G.; Vermeulen, M. J.] Univ York, York YO10 5DD, N Yorkshire, England. [Kaeppeler, F.] Karlsruhe Inst Technol, Inst Kernphys, D-76021 Karlsruhe, Germany. [Koehler, P.] Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. [Lederer, C.; Pavlik, A.; Wallner, A.] Univ Vienna, Fac Phys, A-1010 Vienna, Austria. [Massimi, C.; Mingrone, F.; Vannini, G.] Univ Bologna, Dipartimento Fis, I-40126 Bologna, Italy. [Massimi, C.; Mingrone, F.; Vannini, G.] Sez INFN Bologna, Bologna, Italy. [Mengoni, A.; Ventura, A.] Agenzia Nazl Nuove Tecnol, Eenergia & Sviluppo Econ Sostenibile ENEA, Bologna, Italy. [Milazzo, P. M.] Ist Nazl Fis Nucl, Trieste, Italy. [Mirea, M.; Roman, F.] Horia Hulubei Natl Inst Phys & Nucl Engn, IFIN HH, Bucharest, Romania. [Mondalaers, W.; Plompen, A.; Schillebeeckx, P.] European Commiss JRC, Inst Reference Mat & Measurements, B-2440 Geel, Belgium. [Rauscher, T.] Univ Basel, Dept Phys & Astron, Basel, Switzerland. [Rubbia, C.] Ist Nazl Fis Nucl, Lab Nazl Gran Sasso, Assergi, AQ, Italy. : Elsevier BV. - 0090-3752 .- 1095-9904. ; 119, s. 35-37
  • Tidskriftsartikel (refereegranskat)abstract
    • The angular distribution of fragments emitted in neutron-induced fission of Th-232 was measured in the white spectrum neutron beam at the n_TOF facility at CERN. A reaction chamber based on Parallel Plate Avalanche Counters (PPAC) was used, where the detectors and the targets have been tilted 45 degrees with respect to the neutron beam direction in order to cover the full angular range of the fission fragments. A GEANT4 simulation has been developed to study the setup efficiency. The data analysis and the preliminary results obtained for the Th-232(n,f) between fission threshold and 100 MeV are presented here.
  •  
30.
  • Tarrío, Diego, et al. (författare)
  • Neutron-induced fission cross sections of Th-232 and U-233 up to 1 GeV using parallel plate avalanche counters at the CERN n_TOF facility
  • 2023
  • Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 107:4
  • Tidskriftsartikel (refereegranskat)abstract
    • The neutron-induced fission cross sections of Th-232 and U-233 were measured relative to U-235 in a wide neutron energy range up to 1 GeV (and from fission threshold in the case of Th-232, and from 0.7 eV in case of U-233), using the white-spectrum neutron source at the CERN Neutron Time-of-Flight (n_TOF) facility. Parallel plate avalanche counters (PPACs) were used, installed at the Experimental Area 1 (EAR1), which is located at 185 m from the neutron spallation target. The anisotropic emission of fission fragments were taken into account in the detection efficiency by using, in the case of U-233, previous results available in EXFOR, whereas in the case of Th-232 these data were obtained from our measurement, using PPACs and targets tilted 45 degrees with respect to the neutron beam direction. Finally, the obtained results are compared with past measurements and major evaluated nuclear data libraries. Calculations using the high-energy reaction models INCL++ and ABLA07 were performed and some of their parameters were modified to reproduce the experimental results. At high energies, where no other neutron data exist, our results are compared with experimental data on proton-induced fission. Moreover, the dependence of the fission cross section at 1 GeV with the fissility parameter of the target nucleus is studied by combining those ( p, f) data with our (n, f) data on Th-232 and U-233 and on other isotopes studied earlier at n_TOF using the same experimental setup.
  •  
31.
  • Tatsuno, H., et al. (författare)
  • Future projects of light kaonic atom X-ray spectroscopy
  • 2016
  • Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 130
  • Tidskriftsartikel (refereegranskat)abstract
    • X-ray spectroscopy of light kaonic atoms is a unique tool to provide precise information on the fundamental KN interaction at the low-energy limit and the in-medium nuclear interaction of K-. The future experiments of kaonic deuterium strong-interaction shift and width (SIDDHARTA-2 and J-PARC E57) can extract the isospin dependent K-N interaction at threshold. The high-resolution X-ray spectroscopy of kaonic helium with microcalorimeters (J-PARC E62) has the possibility to solve the long-standing potential-strength problem of the attractive K--nucleus interaction. Here, the recent experimental results and the future projects of X-ray spectroscopy of light kaonic atoms are presented.
  •  
32.
  • Curceanu, C., et al. (författare)
  • Kaonic deuterium measurement with Siddharta-2 on daΦNE
  • 2020
  • Ingår i: Acta Physica Polonica B. - 0587-4254. ; 51:1, s. 251-257
  • Tidskriftsartikel (refereegranskat)abstract
    • The interaction of antikaons with nucleons and nuclei in the low-energy regime represents an active research field in hadron physics with still many important open questions. The investigation of light kaonic atoms is, in this context, a unique tool to obtain precise information on this interaction. The most precise kaonic hydrogen measurement to date, together with an exploratory measurement of kaonic deuterium, were carried out by the SIDDHARTA Collaboration at the DAΦNE electron–positron collider of LNF-INFN, by combining the excellent quality kaon beam delivered by the collider with new experimental techniques, as fast and precise Silicon-Drift X-ray detectors. The measurement of kaonic deuterium will be realized in the near future by SIDDHARTA-2, a major upgrade of SIDDHARTA.
  •  
33.
  • Curceanu, C., et al. (författare)
  • Low-energy kaon-nuclei interaction studies at DAΦNE : Siddharta-2 and amadeus
  • 2017
  • Ingår i: Acta Physica Polonica B. - 0587-4254. ; 48:10, s. 1855-1860
  • Tidskriftsartikel (refereegranskat)abstract
    • The DAΦNE electron-positron collider of the Laboratori Nazionali di Frascati of INFN has made available a unique quality low-energy negatively charged kaons "beam", which is being used to study the kaon-nucleon/nuclei interactions by the SIDDHARTA-2 experiment and the AMADEUS Collaboration. The dynamics of the strong interaction processes in the nonperturbative regime is approached by lattice calculations and effective field theories (ChPT) which are still lacking experimental results in the lowenergy regime, fundamental for their good understanding. The studies of kaonic atoms and of the kaonic nuclear processes performed by SIDDHARTA- 2 and AMADEUS play in this context a key-role.
  •  
34.
  • Curceanu, C., et al. (författare)
  • The kaonic atoms research program at DAΦNE : Overview and perspectives
  • 2018
  • Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 1138:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The interaction of antikaons with nucleons and nuclei in the low-energy regime represents an active research field in hadron physics with still many important open questions. The investigation of light kaonic atoms is, in this context, a unique tool to obtain precise information on this interaction. The energy shift and broadening of the lowest-lying states of such atoms, induced by the kaon-nucleus strong interaction, can be determined with high precision from atomic X-ray spectroscopy. This experimental method provides unique information to understand the low energy kaon-nucleus interaction at threshold. The lightest atomic systems, kaonic hydrogen and kaonic deuterium, deliver the isospin-dependent kaon-nucleon scattering lengths. The most precise kaonic hydrogen measurement to date, together with an exploratory measurement of kaonic deuterium, were carried out by the SIDDHARTA collaboration at the DAΦNE electron-positron collider of LNF-INFN, by combining the excellent quality kaon beam delivered by the collider with new experimental techniques, as fast and precise X-ray detectors: Silicon Drift Detectors. The measurement of kaonic deuterium will be realized in the near future by SIDDHARTA-2, a major upgrade of SIDDHARTA. In this paper an overview of the main results obtained by SIDDHARTA together with the future plans, are given.
  •  
35.
  • De Paolis, L., et al. (författare)
  • Kaonic atoms measurement at DA Φ NE : SIDDHARTA and SIDDHARTA-2
  • 2019
  • Ingår i: Basic Concepts in Nuclear Physics : Theory, Experiments and Applications - 2018 La Rábida International Scientific Meeting on Nuclear Physics - Theory, Experiments and Applications - 2018 La Rábida International Scientific Meeting on Nuclear Physics. - Cham : Springer International Publishing. - 9783030222031 ; 225, s. 191-195
  • Konferensbidrag (refereegranskat)abstract
    • Light kaonic atoms studies provide the unique opportunity to perform experiments equivalent to scattering at threshold, being their atomic binding energies in the keV range. High precision atomic X-rays spectroscopy ensures that the energy shift and broadening of the lowest-lying states of the kaonic atoms, induced by the strong interaction between the kaon and nucleus, can be detected. Kaonic hydrogen and kaonic deuterium are the lightest atomic systems and their study deliver the isospin-dependent kaon-nucleon scattering lengths. The SIDDHARTA collaboration was able to perform the most precise kaonic hydrogen measurement to date, together with an exploratory measurement of kaonic deuterium. The measurement of the kaonic deuterium will be realized in the near future by a major upgrade of SIDDHARTA: SIDDHARTA-2. In this paper an overview of the main results obtained by SIDDHARTA together with the future plans are presented.
  •  
36.
  • Marton, J., et al. (författare)
  • Spectroscopy of kaonic atoms at DAFNE and J-PARC
  • 2019
  • Ingår i: Proceedings - 15th International Workshop on Meson Physics, MESON 2018. - : EDP Sciences.
  • Konferensbidrag (refereegranskat)abstract
    • The interaction of antikaons (K) with nucleons and nuclei in the low-energy regime represents a very active research field in hadron physics. A unique and rather direct experimental access to the antikaon-nucleon scattering lengths is provided by precision X-ray spectroscopy of transitions in low-lying states in the lightest kaonic atoms (i.e. kaonic hydrogen and deuterium). In the SIDDHARTA experiment at the electron-positron collider DAFNE of LNFINFN we measured the most precise values of the strong interaction observables in conic hydrogen. The strong interaction on the 1s ground state of the electromagnetically bound K-p atom causes an energy shift and broadening of the 1s state. SIDDHARTA will extend the spectroscopy to kaonic deuterium to get access to the antikaon-neutron interaction and thus the isospin dependent scattering lengths. At J-PARC a kaon beam is used in a complementary experiment with a different setup for spectroscopy of kaonic deuterium atoms. The talk will give an overview of the of the upcoming experiments SIDDHARTA and the complementary experiment at J-PARC.Furthermore, the implications of the experiments for the theory of low-energy strong interaction with strangeness will be discussed.
  •  
37.
  • Miliucci, M., et al. (författare)
  • Kaonic Deuterium Precision Measurement at DA Φ NE : The SIDDHARTA-2 Experiment
  • 2020
  • Ingår i: Recent Progress in Few-Body Physics : Proceedings of the 22nd International Conference on Few-Body Problems in Physics, FB22 2018 - Proceedings of the 22nd International Conference on Few-Body Problems in Physics, FB22 2018. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. - 9783030323561 - 9783030323578 ; 238, s. 965-969
  • Bokkapitel (refereegranskat)abstract
    • Light kaonic atoms spectroscopy offers the unique opportunity to perform experiments equivalent to scattering at vanishing relative energies. This allows the determination of the antikaon-nucleus interaction at threshold, without the need of extrapolation to zero energy, as in the case of scattering experiments. In this framework, the SIDDHARTA-2 collaboration aims to perform the first measurement of kaonic deuterium transition to the fundamental level, which is mandatory to extract the isospin dependent antikaon—nucleon scattering lengths. The experiment will be carried out at the DA(formula presented)NE collider of LNF-INFN in 2019–2020.
  •  
38.
  • Scordo, A., et al. (författare)
  • The kaonic atoms research program at DAΦNE : From SIDDHARTA to SIDDHARTA-2
  • 2018
  • Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 181
  • Tidskriftsartikel (refereegranskat)abstract
    • The interaction of antikaons with nucleons and nuclei in the low-energy regime represents an active research field in hadron physics with still many important open questions. The investigation of light kaonic atoms, in which one electron is replaced by a negatively charged kaon, is a unique tool to provide precise information on this interaction; the energy shift and the broadening of the low-lying states of such atoms, induced by the kaon-nucleus hadronic interaction, can be determined with high precision from the atomic X-ray spectroscopy, and this experimental method provides unique information to understand the low energy kaon-nucleus interaction at the production threshold. The lightest atomic systems, like the kaonic hydrogen and the kaonic deuterium deliver, in a model-independent way, the isospin-dependent kaon-nucleon scattering lengths. The most precise kaonic hydrogen measurement to-date, together with an exploratory measurement of kaonic deuterium, were carried out in 2009 by the SIDDHARTA collaboration at the DAΦNE electron-positron collider of LNF-INFN, combining the excellent quality kaon beam delivered by the collider with new experimental techniques, as fast and very precise X-ray detectors, like the Silicon Drift Detectors. The SIDDHARTA results triggered new theoretical work, which achieved major progress in the understanding of the low-energy strong interaction with strangeness reflected by the antikaon-nucleon scattering lengths calculated with the antikaon-proton amplitudes constrained by the SIDDHARTA data. The most important open question is the experimental determination of the hadronic energy shift and width of kaonic deuterium; presently, a major upgrade of the setup, SIDDHARTA-2, is being realized to reach this goal. In this paper, the results obtained in 2009 and the proposed SIDDHARTA-2 upgrades are presented.
  •  
39.
  • Sirghi, D., et al. (författare)
  • Experiments with low-energy kaons at the DAΦNE Collider
  • 2019. - 1
  • Ingår i: XIII International Conference on Beauty, Charm and Hyperon Hadrons (BEACH 2018) 17–23 June 2018, Peniche, Portugal. - : IOP Publishing. - 1742-6588. ; 1137
  • Konferensbidrag (refereegranskat)abstract
    • The investigations of light kaonic atoms offer the unique opportunity to perform experiments equivalent to scattering at vanishing relative energies, being their atomic binding energies in the keV range. This allows the determination of the hadron-nucleus interaction at threshold without the need of an extrapolation to zero relative energy. The energy shift and broadening of the lowest-lying states of such atoms, induced by the kaon-nucleus strong interaction, can be determined with high precision from atomic X-ray spectroscopy. The lightest atomic systems, kaonic hydrogen and kaonic deuterium, deliver the isospin-dependent kaon-nucleon scattering lengths. The most precise kaonic hydrogen measurement to date, together with an exploratory measurement of kaonic deuterium, were carried out by the SIDDHARTA collaboration at the DAΦNE electron-positron collider of LNF-INFN. The measurement of kaonic deuterium will be realized in the near future by SIDDHARTA-2, a major upgrade of SIDDHARTA. A correlated study of the kaon-nuclei interaction at momenta below 130 MeV/c is carried out by the AMADEUS collaboration, using the KLOE detector and dedicated targets inserted near the collider interaction point. In this paper an overview of the main results obtained by SIDDHARTA together with the future plans, the SIDDHARTA-2 experiment and with the preliminary results of the study of charged antikaons interacting with nuclei by the AMADEUS collaboration, are shown.
  •  
40.
  • Sirghi, D., et al. (författare)
  • Kaonic atoms measurements at the DAΦNE Collider
  • 2018
  • Ingår i: Proceedings of Science. - 1824-8039. ; 336
  • Konferensbidrag (refereegranskat)abstract
    • The DAΦNE electron-positron collider of the Laboratori Nazionali di Frascati of INFN is a worldwide unique low-energy kaon source, which is being used to produce and to study kaonic atoms by the SIDDHARTA collaboration. The X-ray measurements of kaonic atoms play an important role for understanding the low-energy QCD in the strangeness sector. Significant achievements have been obtained by the SIDDHARTA experiment, among which: the most precise kaonic hydrogen measurement of the 1s level shift and width induced by the presence of the strong interaction; an upper limit of the X-ray yield for kaonic deuterium K-series; the accurate measurement of the 2p level shift and width of kaonic helium-4 and kaonic helium-3; yields of various light kaonic atoms transitions. Using the experience gained with SIDDHARTA experiment, the first kaonic deuterium measurement is in preparation in the framework of the SIDDHARTA-2 experiment, with the goal to determine the antikaon-nucleon isospin dependent scattering lengths, which is possible only by combining the K−p and the upcoming K−d results. An overview of the experimental results of SIDDHARTA and an outlook to SIDDHARTA-2 experiments are given in this paper.
  •  
41.
  • Tarrío, Diego, et al. (författare)
  • Measurement of the angular distribution of fission fragments using a PPAC assembly at CERN n_TOF
  • 2014
  • Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 743, s. 79-85
  • Tidskriftsartikel (refereegranskat)abstract
    • A fission reaction chamber based on Parallel Plate Avalanche Counters (PPACs) was built for measuring angular distributions of fragments emitted in neutron-induced fission of actinides at the neutron beam available at the Neutron Time-Of-Flight (n_TOF) facility at CERN. The detectors and the samples were tilted 45 degrees with respect to the neutron beam direction to cover all the possible values of the emission angle of the fission fragments. The main features of this setup are discussed and results on the fission fragment angular distribution are provided for the Th-232(n,f) reaction around the fission threshold. The results are compared with the available data in the literature, demonstrating the good capabilities of this setup.
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