668 research outputs found

    Nuclear data measurements at the upgraded neutron time-of-flight facility n-TOF at CERN

    Get PDF
    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.Postprint (published version

    Elämyksiä ja kohtaamisia Hopeatien palvelutalon aistihuoneessa

    Get PDF
    Opinn√§ytety√∂n tavoitteena oli selvitt√§√§ ik√§ihmisten kokemuksia aistihuoneen k√§yt√∂st√§ ja kartoittaa, miten he voivat hy√∂ty√§ aistihuoneesta. Apuv√§lineyritys Haltija Groupin SHX-aistihuoneen elementit siirrettiin Helsingin kaupungin Hopeatien palvelutaloon testik√§ytt√∂√∂n kolmeksi kuukaudeksi. Opinn√§ytety√∂ pohjautuu Gary Kielhofnerin inhimillisen toiminnan malliin ‚ÄúModel of Human Occupation (MOHO)‚ÄĚ ja sen keskeiset k√§sitteet ohjasivat tutkimusaineiston tiedon keruuta sek√§ sen analysointia. Opinn√§ytety√∂n muu teoreettinen perusta muodostui ik√§√§ntymisen tarkastelusta toimintakyvyn ja aistien n√§k√∂kulmasta sek√§ multisensorisen toiminnan perusteista. Opinn√§ytety√∂ perustui laadullisen tutkimuksen periaatteisiin ja siin√§ oli kaksi ty√∂el√§m√§kumppania: Helsingin kaupungin Hopeatien palvelutalo ja Haltija Group. Tutkimusmenetelmiksi valittiin aistihuoneen k√§ytt√§jille suunnattu kyselylomake sek√§ hoitohenkil√∂kunnalle suunnattu ryhm√§muotoinen teemahaastattelu. Kirjallinen raporttiosuus sis√§lt√§√§ teoreettisen perustan, opinn√§ytety√∂n toteutuksen kuvauksen, aineiston analyysin, johtop√§√§t√∂kset ja pohdinnan. T√§ss√§ opinn√§ytety√∂ss√§ asiakasl√§ht√∂isyys ja aistihuoneen esteett√∂myys nousivat seikoiksi, jotka vaikuttivat my√∂nteisesti ik√§√§ntyneen osallistumiseen aistihuoneessa. Asiakkaan el√§m√§nhistorian ja mielenkiinnon kohteiden tunteminen sek√§ yksil√∂llisen tahdon ja suorituskyvyn huomioiminen koettiin t√§rkeiksi. Onnistuneeseen k√§yntiin aistihuoneessa vaikuttivat orientaatio ja henkil√∂kunnan taito k√§ytt√§√§ aistihuoneen tekniikkaa. Asiakkaiden kokemukset aistihuoneesta olivat p√§√§osin miellytt√§vi√§, jopa rentouttavia. T√§m√§n opinn√§ytety√∂n tulokset ovat yhten√§isess√§ linjassa verrattuna aiempiin tutkimuksiin aistihuoneista ja niiden vaikutuksista. Opinn√§ytety√∂n perusteella aistihuoneen k√§ytt√∂ ik√§√§ntyneiden arjessa voi tarjota positiivisia vaikutuksia ik√§√§ntyneen psyykkiseen ja sosiaaliseen toimintakykyyn. Huolellinen suunnittelu, esteett√∂myys ja vahva asiakastuntemus mahdollistavat asiakkaan osallistumisen terapeuttiseen toimintaan aistihuoneessa. Aistihuoneen vaikuttavuudesta pitk√§ll√§ aikav√§lill√§ tarvitaan lis√§√§ tutkimustietoa, jota voisi hy√∂dynt√§√§ my√∂s suunniteltaessa tulevaisuuden palveluja ik√§√§ntyneille.The object of the Bachelor‚Äôs 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‚Äôs 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‚Äô 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‚Äôs 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

    Advances in evaporated solid-phase-crystallized poly-si thin-film solar cells on glass (EVA)

    Get PDF
    10.1155/2008/532351Advances in OptoElectronics2008

    First Measurement of 72Ge(n,ő≥) at n_TOF

    Get PDF
    9th European Summer School on Experimental Nuclear AstrophysicsThe slow neutron capture process (s-process) is responsible for producing about half of the elemental abundances heavier than iron in the universo

    Recent results in nuclear astrophysics at the n_TOF facility at CERN

    Get PDF
    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

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

    Get PDF
    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

    Operational Experience with a LHC Collimator Prototype in the CERN SPS

    Get PDF
    A full-scale prototype of the Large Hadron Collider (LHC) collimator was installed in 2004 in the CERN Super Proton Synchrotron (SPS) and has been extensively used for beam tests, for control tests and also LHC simulation benchmarking during four years of operation. This operational experience has been extremely valuable in view of the final LHC implementation as well as for estimating the LHC operational scenarios, most notably to establish procedures for the beam-based alignment of the collimators with respect to the circulating beam. These studies were made possible by installing in the SPS a first prototype of the LHC beam loss monitoring system. The operational experience gained at the SPS and the lessons learnt for the LHC operation are presented

    Measurement of the radiative capture cross section of the s-process branching points 204Tl and 171Tm at the n-TOF facility (CERN)

    Get PDF
    The neutron capture cross section of some unstable nuclei is especially relevant for s-process nucleosynthesis studies. This magnitude is crucial to determine the local abundance pattern, which can yield valuable information of the s-process stellar environment. In this work we describe the neutron capture (n,ő≥) measurement on two of these nuclei of interest, 204Tl and 171Tm, from target production to the final measurement, performed successfully at the n_TOF facility at CERN in 2014 and 2015. Preliminary results on the ongoing experimental data analysis will also be shown. These results include the first ever experimental observation of capture resonances for these two nuclei.The authors acknowledge financial support by the Spanish FPA2014-52823-C2-2-P project, by the EC Marie Curie Action ‚ÄúNeutAndalus‚ÄĚ (FP7-PEOPLE-2012-CIG- 334315), by the ARGOS scholarship of the Spanish Nuclear Safety Council (CSN) and the Universitat Polit√®cnica de Catalunya, and by the University of Sevilla via the VI PPIT-US program

    Upgrades Of the SPS, Transfer Line and LHC Injection Protection Devices For the HL-LHC Era

    Full text link
    The challenging High Luminosity LHC (HL-LHC) beam requirements will lead in the future to unprecedented beam parameters along the LHC injector chain. In the SPS accelerator these requests translate into about a factor two higher intensity and brightness than the present design performance. In addition to the challenge of producing and accelerating such beams, these parameters affect the resistance of the existing equipment against beam impact. Most of the protection devices in the SPS ring, its transfer lines and the LHC injection areas will be put under operational constraints which are beyond their design specification. The equipment concerned has been reviewed and their resistance to the HL-LHC beams checked. Theoretical and simulation studies have been performed for the SPS beam scraping system, the protection devices and the dump absorbers of the SPS-to-LHC transfer lines, as well as for the LHC injection protection devices. The first results of these studies are reported, together with the future prospects.Comment: 3 p. Presented at 4th International Particle Accelerator Conference (IPAC 2013
    • ‚Ķ
    corecore