Neutron capture on ^{205}Tl: depicting the abundance pattern of lead isotopes in s-process nucleosynthesis

Proposal: Neutron capture on 205Tl: depicting the abundance pattern of lead isotopes in s-process nucleosynthesisWe propose to use the TOF technique to measure the neutron capture cross section of 205Tl(n,gamma) over the full energy range of stellar interest. An accurate measurement of this cross section is needed for a complete and consistent understanding of the s-process nucleosynthesis of the heaviest nuclei which are produced in low-mass and low metallicity AGB-stars. The only previous TOF measurement has yield only a partial information, insufficient for a reliable analysis of the complex branching pattern around 205Pb and 205Tl. Furthermore, there is also a discrepancy of 40% between the two previous activation measurements made at kT=24 keV. The cross section of 205Tl(n,gamma) is particularly relevant because it affects the equilibrium that is established in some stellar conditions between the 205Tl -> 205Pb bound-state Beta-decay and the 205Pb -> 205Tl E.C. decay. This effect induces a complex interplay which influences the final s-process abundance of both nuclei. We propose to measure accurately and with high resolution the 205Tl(n,gamma) cross section by using a set of four C6D6 detectors in combination with the pulsed neutron-source of CERN n_TOF.Preprin

Measurement of the 235U(n,f) cross section relative to the 6Li(n,t) and 10B(n,a) standards from thermal to 170 keV neutron energy range at n_TOF

The 235U(n,f) cross section was measured in a wide energy range at n_TOF relative to 6Li(n,t) and 10B(n,alpha), with high resolution and in a wide energy range, with a setup based on a stack of six samples and six silicon detectors placed in the neutron beam. This allowed us to make a direct comparison of the reaction yields under the same experimental conditions, and taking into account the forward/backward emission asymmetry. A hint of an anomaly in the 10÷30 keV neutron energy range had been previously observed in other experiments, indicating a cross section systematically lower by several percent relative to major evaluations. The present results indicate that the evaluated cross section in the 9÷18 keV neutron energy range is indeed overestimated, both in the recent updates of ENDF/B-VIII.0 and of the IAEA reference data. Furthermore, these new high-resolution data confirm the existence of resonance-like structures in the keV neutron energy region. The new, high accuracy results here reported may lead to a reduction of the uncertainty in the 1÷100 keV neutron energy region. Finally, the present data provide additional confidence on the recently re-evaluated cross section integral between 7.8 and 11 eV.Preprin

Preliminary results on the 233U capture cross section and alpha ratio measured at n_TOF (CERN) with the fission tagging technique

233U is of key importance among the fissile nuclei in the Th-U fuel cycle. A particularity of 233U is its small neutron capture cross-section, which is on average about one order of magnitude lower than the fission cross-section.The accuracy in the measurement of the 233U capture cross-section depends crucially onan efficient capture-fission discrimination, thus a combined set-up of fission and ¿-detectors is needed. A measurement of the 233U capture cross-section and capture-to-fissionratio was performed at the CERN n_TOF facility. The Total Absorption Calorimeter (TAC) of n_TOF was employed as ¿-detector coupled with a novel compact ionization chamber as fission detector. A brief description of the experimental set-up will be given, and essential parts of the analysis procedure as well as the preliminary response of the set-up to capture are presented and discussedPostprint (published version

Elämyksiä ja kohtaamisia Hopeatien palvelutalon aistihuoneessa

Opinnäytetyön tavoitteena oli selvittää ikäihmisten kokemuksia aistihuoneen käytöstä ja kartoittaa, miten he voivat hyötyä aistihuoneesta. Apuvälineyritys Haltija Groupin SHX-aistihuoneen elementit siirrettiin Helsingin kaupungin Hopeatien palvelutaloon testikäyttöön kolmeksi kuukaudeksi. Opinnäytetyö pohjautuu Gary Kielhofnerin inhimillisen toiminnan malliin “Model of Human Occupation (MOHO)” ja sen keskeiset käsitteet ohjasivat tutkimusaineiston tiedon keruuta sekä sen analysointia. Opinnäytetyön muu teoreettinen perusta muodostui ikääntymisen tarkastelusta toimintakyvyn ja aistien näkökulmasta sekä multisensorisen toiminnan perusteista. Opinnäytetyö perustui laadullisen tutkimuksen periaatteisiin ja siinä oli kaksi työelämäkumppania: Helsingin kaupungin Hopeatien palvelutalo ja Haltija Group. Tutkimusmenetelmiksi valittiin aistihuoneen käyttäjille suunnattu kyselylomake sekä hoitohenkilökunnalle suunnattu ryhmämuotoinen teemahaastattelu. Kirjallinen raporttiosuus sisältää teoreettisen perustan, opinnäytetyön toteutuksen kuvauksen, aineiston analyysin, johtopäätökset ja pohdinnan. Tässä opinnäytetyössä asiakaslähtöisyys ja aistihuoneen esteettömyys nousivat seikoiksi, jotka vaikuttivat myönteisesti ikääntyneen osallistumiseen aistihuoneessa. Asiakkaan elämänhistorian ja mielenkiinnon kohteiden tunteminen sekä yksilöllisen tahdon ja suorituskyvyn huomioiminen koettiin tärkeiksi. Onnistuneeseen käyntiin aistihuoneessa vaikuttivat orientaatio ja henkilökunnan taito käyttää aistihuoneen tekniikkaa. Asiakkaiden kokemukset aistihuoneesta olivat pääosin miellyttäviä, jopa rentouttavia. Tämän opinnäytetyön tulokset ovat yhtenäisessä linjassa verrattuna aiempiin tutkimuksiin aistihuoneista ja niiden vaikutuksista. Opinnäytetyön perusteella aistihuoneen käyttö ikääntyneiden arjessa voi tarjota positiivisia vaikutuksia ikääntyneen psyykkiseen ja sosiaaliseen toimintakykyyn. Huolellinen suunnittelu, esteettömyys ja vahva asiakastuntemus mahdollistavat asiakkaan osallistumisen terapeuttiseen toimintaan aistihuoneessa. Aistihuoneen vaikuttavuudesta pitkällä aikavälillä tarvitaan lisää tutkimustietoa, jota voisi hyödyntää myös suunniteltaessa tulevaisuuden palveluja ikääntyneille.The object of the Bachelor’s thesis was to provide the elderly in the Hopeatie service house in Helsinki with the SHX multisensory elements for trial use. The purpose of this study was to find out experiences of elderly people in the multisensory room and analyze how they can benefit from the multisensory activities in their rehabilitation. The theory is based on Gary Kielhofner’s Model of Human Occupation (MOHO) and its essential concepts that steer the data gathering and analysis. The fundamental aspects of multisensory activities and ageing accompanied by changes in performance and impaired senses are also observed. This thesis is a qualitive study executed in collaboration with two working life partners: the city of Helsinki and Haltija Group, which is a Finnish company for assistive devices, welfare technology and rehabilitation. The thematic group interview of six employees of the service house and a client questionnaire were chosen as research methods. This thesis consists of theory, description of the implementation, data analysis, results of the study, and conclusions and discussion. The results show that the client-centered approach and the accessibility to the multisensory room had an influence on participation of the elderly in the multisensory room. Successful visits of the multisensory room were enabled by employees’ skills to prepare the client for the visit and their skills to master the technology of the room. The experiences of the elderly in the multisensory room were mainly pleasant, some even relaxing. The results of this study are consistent with previous research on the effects of a multisensory room. This study proves that the use of the multisensory room in the elderly people’s daily lives may have a positive effect on their mental and social performance. Thorough planning of therapy intervention, easy access to the multisensory room and strong client knowledge enable committed client participation. More research is needed for long-term effects of multisensory room in order to benefit from the results for planning services for the elderly in the future

(n,cp) reactions study at the n_TOF facilitty at CERN: results for the cosmological lithium problem

The Big Bang Nucleosynthesis describes the production of the lightest nuclides from deuterium to Li at the early stages of the Universe. While a general good agreement is found for most of the isotopes involved in the synthesis, a serious discrepancy between the predicted abundance of 7Li and the related experimental observations is still present. This discrepancy has been referred since several decades as Cosmological Lithium Problem. In one last attempt to find nuclear solutions to this longstanding conundrum, the 7Be(n,alpha)4He and 7Be(n,p)7Li reactions, that affect predominantly the production of 7Li via the destruction of his parent nucleus 7Be, have been studied. Here we present the 7Be(n,a)4He and 7Be(n,p)7Li reaction crosssection measurements performed at the high-resolution n_TOF facility using the time-of-flight technique and high purity samples. The result of the experiments definitely rules out neutron induced reactions as a solution to the puzzle, thus indicating that explanations have to be sought out in other Physics scenarios.Postprint (published version

Recent results in nuclear astrophysics at the n_TOF facility at CERN

The neutron time of flight (n_TOF) facility at CERN is a spallation source characterized by a white neutron spectrum. The innovative features of the facility, in the two experimental areas, (20 m and 185 m), allow for an accurate determination of the neutron cross section for radioactive samples or for isotopes with small neutron capture cross section, of interest for Nuclear Astrophysics. The recent results obtained at n_TOF facility are presented.Postprint (published version

The CERN n_TOF facility: a unique tool for nuclear data measurement

The study of the resonant structures in neutron-nucleus cross-sections, and therefore of the compoundnucleus reaction mechanism, requires spectroscopic measurements to determine with high accuracy the energy of the neutron interacting with the material under study. To this purpose, the neutron time-of-flight facility n_TOF has been operating since 2001 at CERN. Its characteristics, such as the high intensity instantaneous neutron flux, the wide energy range from thermal to few GeV, and the very good energy resolution, are perfectly suited to perform highquality measurements of neutron-induced reaction cross sections. The precise and accurate knowledge of these cross sections plays a fundamental role in nuclear technologies, nuclear astrophysics and nuclear physics. Two different measuring stations are available at the n_TOF facility, called EAR1 and EAR2, with different characteristics of intensity of the neutron flux and energy resolution. These experimental areas, combined with advanced detection systems lead to a great flexibility in performing challenging measurement of high precision and accuracy, and allow the investigation isotopes with very low cross sections, or available only in small quantities, or with very high specific activity. The characteristics and performances of the two experimental areas of the n_TOF facility will be presented, together with the most important measurements performed to date and their physics case. In addition, the significant upcoming measurements will be introduced.Postprint (published version

Measurement of the N 14 (n,p) C 14 cross section at the CERN n_TOF facility from subthermal energy to 800 keV

Background: The 14N(n,p)14C reaction is of interest in neutron capture therapy, where nitrogen-related dose is the main component due to low-energy neutrons, and in astrophysics, where 14N acts as a neutron poison in the s process. Several discrepancies remain between the existing data obtained in partial energy ranges: thermal energy, keV region, and resonance region. Purpose: We aim to measure the 14N(n,p)14C cross section from thermal to the resonance region in a single measurement for the first time, including characterization of the first resonances, and provide calculations of Maxwellian averaged cross sections (MACS). Method: We apply the time-of-flight technique at Experimental Area 2 (EAR-2) of the neutron time-of-flight (n_TOF) facility at CERN. 10B(n,a)7Li and 235U(n,f) reactions are used as references. Two detection systems are run simultaneously, one on beam and another off beam. Resonances are described with the R-matrix code sammy. Results: The cross section was measured from subthermal energy to 800 keV, resolving the first two resonances (at 492.7 and 644 keV). A thermal cross section was obtained (1.809±0.045 b) that is lower than the two most recent measurements by slightly more than one standard deviation, but in line with the ENDF/B-VIII.0 and JEFF-3.3 evaluations. A 1/v energy dependence of the cross section was confirmed up to tens of keV neutron energy. The low energy tail of the first resonance at 492.7 keV is lower than suggested by evaluated values, while the overall resonance strength agrees with evaluations. Conclusions: Our measurement has allowed determination of the 14N(n,p) cross section over a wide energy range for the first time. We have obtained cross sections with high accuracy (2.5%) from subthermal energy to 800 keV and used these data to calculate the MACS for kT=5 to kT=100 keV.We thank Mr. Wilhelmus Vollenberg for the preparation of the adenine samples. This work was partially supported by Spanish Ministerio de Ciencia e Innovación (PID2020- 117969RB-I00), Junta de Andalucía (FEDER Andalucia 2014-2020) Projects No. P20-00665 and No. B-FQM-156- UGR20. This work was also supported by the UK Science and Facilities Council (ST/M006085/1, ST/P004008/1), by the European Research Council ERC-2015-StG No. 677497, and by the funding agencies of the n_TOF participating in- stitutes. P.T. acknowledges support from the Spanish Ministry of Science, Innovation and Universities under the FPU Grant No. FPU17/02305.Article signat per 132 autors/es: Pablo Torres-Sánchez, Javier Praena, Ignacio Porras, Marta Sabaté-Gilarte, Claudia Lederer-Woods, Oliver Aberle, Victor Alcayne, Simone Amaducci, Józef Andrzejewski, Laurent Audouin, Vicente Bécares, Victor Babiano-Suarez, Michael Bacak, Massimo Barbagallo, František Beˇcváˇr, Giorgio Bellia, Eric Berthoumieux, Jon Billowes, Damir Bosnar, Adam Brown, Maurizio Busso, Manuel Caamaño, Luis Caballero, Francisco Calviño, Marco Calviani, Daniel Cano-Ott, Adria Casanovas, Francesco Cerutti, Yonghao Chen, Enrico Chiaveri, Nicola Colonna, Guillem Cortés, Miguel Cortés-Giraldo, Luigi Cosentino, Sergio Cristallo, Lucia-Anna Damone, Maria Diakaki, Mirco Dietz, César Domingo-Pardo, Rugard Dressler, Emmeric Dupont, Ignacio Durán, Zinovia Eleme, Beatriz Fernández-Domínguez, Alfredo Ferrari, Francisco Javier Ferrer, Paolo Finocchiaro, Valter Furman, Kathrin Göbel, Ruchi Garg, Aleksandra Gawlik-Ramiega, Benoit Geslot, Simone Gilardoni, Tudor Glodariu, Isabel Gonçalves, Enrique González-Romero, Carlos Guerrero, Frank Gunsing, Hideo Harada, Stephan Heinitz, Jan Heyse, David Jenkins, Erwin Jericha, Franz Käppeler, Yacine Kadi, Atsushi Kimura, Niko Kivel, Michael Kokkoris, Yury Kopatch, Milan Krtiˇcka, Deniz Kurtulgil, Ion Ladarescu, Helmut Leeb, Jorge Lerendegui-Marco, Sergio Lo Meo, Sarah-Jane Lonsdale, Daniela Macina, Alice Manna, Trinitario Martínez, Alessandro Masi, Cristian Massimi, Pierfrancesco Mastinu, Mario Mastromarco, Francesca Matteucci, Emilio-Andrea Maugeri, Annamaria Mazzone, Emilio Mendoza, Alberto Mengoni, Veatriki Michalopoulou, Paolo Maria Milazzo, Federica Mingrone, Agatino Musumarra, Alexandru Negret, Ralf Nolte, Francisco Ogállar, Andreea Oprea, Nikolas Patronis, Andreas Pavlik, Jarosław Perkowski, Luciano Persanti, José-Manuel Quesada, Désirée Radeck, Diego Ramos-Doval, Thomas Rauscher, René Reifarth, Dimitri Rochman, Carlo Rubbia, Alok Saxena, Peter Schillebeeckx, Dorothea Schumann, Gavin Smith, Nikolay Sosnin, Athanasios Stamatopoulos, Giuseppe Tagliente, José Tain, Zeynep Talip, Ariel Tarifeño-Saldivia, Laurent Tassan-Got, Andrea Tsinganis, Jiri Ulrich, Sebastian Urlass, Stanislav Valenta, Gianni Vannini, Vincenzo Variale, Pedro Vaz, Alberto Ventura, Vasilis Vlachoudis, Rosa Vlastou, Anton Wallner, PhilipJohn Woods, Tobias Wright, and Petar Žugec.Postprint (published version

Measurement of the 77Se(n,¿) cross section up to 200 keV at the n_TOF facility at CERN

The 77Se(n,¿) reaction is of importance for 77Se abundance during the slow neutron capture process in massive stars. We have performed a new measurement of the 77Se 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 77Se abundances produced through the slow neutron capture process in selected stellar models of 15M¿ and 2M¿, respectively, compared to using previous recommendation of the cross section.This work was supported by the UK Science and Facilities Council (ST/M006085/1), the MSMT of the Czech Republic, the Charles University UNCE/SCI/013 project, the European Research Council ERC-2015-StG No. 677497, and by the funding agencies of the participating institutes. In line with the principles that apply to scientific publishing and the CERN policy in matters of scientific publications, the n_TOF Col- laboration recognizes the work of Y. Kopatch and V. Furman (JINR, Russia), who have contributed to the experiment used to obtain the results described in this paper.Article signat per 131 autors/es: N. V. Sosnin , C. Lederer-Woods, M. Krtiˇcka, R. Garg, M. Dietz, M. Bacak, M. Barbagallo, U. Battino, S. Cristallo, L. A. Damone, M. Diakaki, S. Heinitz, D. Macina, M. Mastromarco, F. Mingrone, A. St. J. Murphy, G. Tagliente, S. Valenta, D. Vescovi, O. Aberle, V. Alcayne, S. Amaducci, J. Andrzejewski, L. Audouin, V. Bécares, V. Babiano-Suarez, F. Beˇcváˇr, G. Bellia, E. Berthoumieux, J. Billowes, D. Bosnar, A. Brown, M. Busso, M. Caamaño, L. Caballero, F. Calviño, M. Calviani, D. Cano-Ott, A. Casanovas, F. Cerutti, Y. H. Chen, E. Chiaveri, N. Colonna, G. Cortés, M. A. Cortés-Giraldo, L. Cosentino, C. Domingo-Pardo, R. Dressler, E. Dupont, I. Durán, Z. Eleme, B. Fernández-Domínguez, A. Ferrari, P. Finocchiaro, K. Göbel, A. Gawlik-Rami˛ega, S. Gilardoni, T. Glodariu, I. F. Gonçalves, E. González-Romero, C. Guerrero, F. Gunsing, H. Harada, J. Heyse, D. G. Jenkins, E. Jericha, F. Käppeler, Y. Kadi, A. Kimura, N. Kivel, M. Kokkoris, D. Kurtulgil, I. Ladarescu, H. Leeb, J. Lerendegui-Marco, S. Lo Meo, S. J. Lonsdale, A. Manna, T. Martínez, A. Masi, C. Massimi, P. Mastinu, F. Matteucci, E. A. Maugeri, A. Mazzone, E. Mendoza, A. Mengoni, V. Michalopoulou, P. M. Milazzo, A. Musumarra, A. Negret, R. Nolte, F. Ogállar, A. Oprea, N. Patronis, A. Pavlik, J. Perkowski, L. Piersanti, I. Porras, J. Praena, J. M. Quesada, D. Radeck, D. Ramos-Doval, T. Rauscher, R. Reifarth, D. Rochman, C. Rubbia, M. Sabaté-Gilarte, A. Saxena, P. Schillebeeckx, D. Schumann, A. G. Smith, A. Stamatopoulos, J. L. Tain, T. Talip, A. Tarifeño-Saldivia, L. Tassan-Got, P. Torres-Sánchez, A. Tsinganis, J. Ulrich, S. Urlass, G. Vannini, V. Variale, P. Vaz, A. Ventura, V. Vlachoudis, R. Vlastou, A. Wallner, P. J. Woods,T. Wright, and P. Žugec.Postprint (published version

Measurement of the neutron-induced fission cross section of Th 230 at the CERN n_TOF facility

The neutron-induced fission cross section of 230 Th has been measured at the neutron time-of-flight facility n_TOF located at CERN. The experiment was performed at the experimental area EAR-1 with a neutron flight path of 185 m, using Micromegas detectors for the detection of the fission fragments. The 230 Th(n, f ) cross section was determined relative to the 235 U(n, f ) one, covering the energy range from the fission threshold up to 400 MeV. The results from the present work are compared with existing cross-section datasets and the observed discrepancies are discussed and analyzed. Finally, using the code EMPIRE 3.2.3 a theoretical study, based on the statistical model, was performed leading to a satisfactory reproduction of the experimental results with the proper tuning of the respective parameters, while for incident neutron energy beyond 200 MeV the fission of 230 Th was described by Monte Carlo simulations.This project received funding from the Euratom “Support safe operation of nuclear systems” program 2014–2018 under Grant Agreement No. 847552 (SANDA) and by the funding agencies of the participating institutes. This research is imple- mented through the IKY scholarships program and cofinanced by the European Union (European Social Fund ’ESF) and Greek national funds through the action entitled “Reinforce- ment of Postdoctoral Researchers - 2nd call (MIS 5033021)”, in the framework of the Operational Programme “Human Resources Development Program, Education and Lifelong Learning” of the National Strategic Reference Framework.Article signat per 137 autors/es: V. Michalopoulou, A. Stamatopoulos, M. Diakaki, A. Tsinganis, R. Vlastou, M. Kokkoris, N. Patronis, Z. Eleme, D. Macina, L. Tassan-Got, N. Colonna, E. Chiaveri, A. Ventura, P. Schillebeeckx, J. Heyse, G. Sibbens, G. Alaerts, A. Borella, A. Moens, D. Vanleeuw, O. Aberle, V. Alcayne, S. Amaducci, J. Andrzejewski, L. Audouin, V. Babiano-Suarez, M. Bacak, M. Barbagallo, S. Bennett, E. Berthoumieux, J. Billowes, D. Bosnar, A. Brown, M. Busso, M. Caamaño, L. Caballero, F. Calviño, M. Calviani, D. Cano-Ott, A. Casanovas, F. Cerutti, G. Cortés, M. A. Cortés-Giraldo, L. Cosentino, S. Cristallo, L. A. Damone, P. J. Davies, M. Dietz, C. Domingo-Pardo, R. Dressler, Q. Ducasse, E. Dupont, I. Durán, B. Fernández-Domínguez, A. Ferrari, P. Finocchiaro, V. Furman, K. Göbel, R. Garg, A. Gawlik-Ramiega, S. Gilardoni, I. F. Gonçalves, E. González-Romero, C. Guerrero, F. Gunsing, H. Harada, S. Heinitz, D. G. Jenkins, A. Junghans, F. Käppeler, Y. Kadi, A. Kimura, I. Knapová, Y. Kopatch, M. Krticka, D. Kurtulgil, I. Ladarescu, C. Lederer-Woods, H. Leeb, J. Lerendegui-Marco, S. J. Lonsdale, A. Manna, T. Martínez, A. Masi, C. Massimi, P. Mastinu, M. Mastromarco, E. A. Maugeri, A. Mazzone, E. Mendoza, A. Mengoni, P. M. Milazzo, F. Mingrone, J. Moreno-Soto, A. Musumarra, A. Negret, R. Nolte, F. Ogállar, A. Oprea, A. Pavlik, J. Perkowski, C. Petrone, L. Piersanti, E. Pirovano, I. Porras, J. Praena, J. M. Quesada, D. Ramos-Doval, T. Rauscher, R. Reifarth, D. Rochman, Y. Romanets, C. Rubbia, M. Sabaté-Gilarte, A. Saxena, D. Schumann, A. Sekhar, A. G. Smith, N. V. Sosnin, P. Sprung, G. Tagliente, J. L. Tain, A. Tarifeño-Saldivia, Th. Thomas, P. Torres-Sánchez, J. Ulrich, S. Urlass, S. Valenta, G. Vannini, V. Variale, P. Vaz, D. Vescovi, V. Vlachoudis, A. Wallner, P. J. Woods, T. Wright, and P. Žugec.Postprint (published version