906 research outputs found

    Post-LS3 Experimental Options in ECN3

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    International audienceThe Experimental Cavern North 3 (ECN3) is an underground experimental cavern on the CERN Prévessin site. ECN3 currently hosts the NA62 experiment, with a physics programme devoted to rare kaon decays and searches of hidden particles approved until Long Shutdown 3 (LS3). Several options are proposed on the longer term in order to make best use of the worldwide unique potential of the high-intensity/high-energy proton beam extracted from the Super Proton Synchrotron (SPS) in ECN3. The current status of their study by the CERN Physics Beyond Colliders (PBC) Study Group is presented, including considerations on beam requirements and upgrades, detector R&D and construction, schedules and cost, as well as physics potential within the CERN and worldwide landscape

    Post-LS3 Experimental Options in ECN3

    No full text
    International audienceThe Experimental Cavern North 3 (ECN3) is an underground experimental cavern on the CERN Prévessin site. ECN3 currently hosts the NA62 experiment, with a physics programme devoted to rare kaon decays and searches of hidden particles approved until Long Shutdown 3 (LS3). Several options are proposed on the longer term in order to make best use of the worldwide unique potential of the high-intensity/high-energy proton beam extracted from the Super Proton Synchrotron (SPS) in ECN3. The current status of their study by the CERN Physics Beyond Colliders (PBC) Study Group is presented, including considerations on beam requirements and upgrades, detector R&D and construction, schedules and cost, as well as physics potential within the CERN and worldwide landscape

    New detection systems for an enhanced sensitivity in key stellar (n,ő≥) measurements

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    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 (‚ąľmg) 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,ő≥) 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,ő≥) 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,ő≥).Title in Web of Science: New detection systems for an enhanced sensitivity in key stellar (n,gamma) measurements</p

    High resolution

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    Neutron capture cross section measurements of isotopes close to s-process branching-points are of fundamental importance for the understanding of this nucleosynthesis mechanism through which about 50% of the elements heavier than iron are produced. We present in this contribution the results corresponding to the high resolution measurement, for first time ever, of the 80Se(n, ő≥) cross section, in which 98 resonances never measured before have been reported. As a consequence, ten times more precise values for the MACS have been obtained compared to previous accepted value adopted in the astrophysical KADoNiS data base

    Measurement of the 77Se(n,ő≥)^{77}Se ( n , ő≥ ) cross section up to 200 keV at the n_TOF facility at CERN

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    The 77Se(n,ő≥)^{77}Se ( n , ő≥ ) reaction is of importance for 77Se^{77}Se abundance during the slow neutron capture process in massive stars. We have performed a new measurement of the 77Se^{77}Se radiative neutron capture cross section at the Neutron Time-of-Flight facility at CERN. Resonance capture kernels were derived up to 51 keV and cross sections up to 200 keV. Maxwellian-averaged cross sections were calculated for stellar temperatures between kT=5¬†keVkT=5 \space keV and kT=100¬†keVkT=100\space keV, with uncertainties between 4.2% and 5.7%. Our results lead to substantial decreases of 14% and 19% in 77Se^{77}Se abundances produced through the slow neutron capture process in selected stellar models of 15M‚äô15M‚äô and 2M‚äô2M‚äô, respectively, compared to using previous recommendation of the cross section

    Measurement of the

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    The neutron capture cross section of 241Am is an important quantity for nuclear energy production and fuel cycle scenarios. Several measurements have been performed in recent years with the aim to reduce existing uncertainties in evaluated data. Two previous measurements, performed at the 185 m flight-path station EAR1 of the neutron time-of-flight facility n_TOF at CERN, have permitted to substantially extend the resolved resonance region, but suffered in the near-thermal energy range from the unfavorable signal-to-background ratio resulting from the combination of the high radioactivity of 241Am and the rather low thermal neutron flux. The here presented 241Am(n,ő≥) measurement, performed with C6D6 liquid scintillator gamma detectors at the 20 m flight-path station EAR2 of the n_TOF facility, took advantage of the much higher neutron flux. The current status of the analysis of the data, focussed on the low-energy region, will be described here

    Compton imaging for enhanced sensitivity (n,ő≥) cross section TOF experiments: Status and prospects

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    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

    Measurement of the <math><mrow><mmultiscripts><mi>Se</mi><mprescripts/><none/><mn>77</mn></mmultiscripts><mo>(</mo><mi>n</mi><mo>,</mo><mi>ő≥</mi><mo>)</mo></mrow></math> cross section¬†up to 200 keV at the n_TOF facility at CERN

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    International audienceThe Se77(n,ő≥) reaction is of importance for Se77 abundance during the slow neutron capture process in massive stars. We have performed a new measurement of the Se77 radiative neutron capture cross section¬†at the Neutron Time-of-Flight facility at CERN. Resonance capture kernels were derived up to 51 keV and cross sections¬†up to 200 keV. Maxwellian-averaged cross sections¬†were calculated for stellar temperatures between kT=5keV and kT=100keV, with uncertainties between 4.2% and 5.7%. Our results lead to substantial decreases of 14% and 19% in Se77 abundances produced through the slow neutron capture process in selected stellar models of 15M‚äô and 2M‚äô, respectively, compared to using previous recommendation of the cross section

    Results of the

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    Accurate neutron capture cross section data for minor actinides (MAs) are required to estimate the production and transmutation rates of MAs in light water reactors, critical fast reactors like Gen-IV systems, and other innovative reactor systems such as accelerator driven systems (ADS). In particular, 244Cm, 246Cm and 248Cm play a role in the transport, storage and transmutation of the nuclear waste of the current nuclear reactors, due to the contribution of these isotopes to the radiotoxicity, neutron emission, and decay heat in the spent nuclear fuel. Also, capture reactions in these Cm isotopes open the path for the formation of heavier elements. In this work, the results of the capture cross section measurement on 244Cm, 246Cm and 248Cm performed at the CERN n_TOF facility are presented. It is important to notice that the Cm samples used in the experiment at n_TOF have been used previously in an experiment at J-PARC, this experiment and the previous one done in the 70s with a nuclear explosion were the only previous capture experiments for these isotopes. At n_TOF, the capture cross section measurements of 244Cm, 246Cm and 248Cm were performed at the 20 m vertical flight path (EAR2) with three C6D6 total energy detectors. In addition, the cross section of 244Cm was measured at the 185 m flight path (EAR1) with a Total Absorption Calorimeter (TAC). The combination of measurements in EAR1 and EAR2 has contributed to controlling and reducing the systematic uncertainties in the results. The compatibility of the different measurements performed and the techniques to obtain the results are presented in this paper as well as the procedure to obtain the resonance parameters

    Advances and new ideas for neutron-capture astrophysics experiments at CERN n_TOF

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    This article presents a few selected developments and future ideas related to the measurement of (n,ő≥) 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 ő≥-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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