The 93Zr(n, γ) reaction up to 8 keV neutron energy

The (n,γ) reaction of the radioactive isotope 93Zr has been measured at the n-TOF high-resolution time-of-flight facility at CERN. Resonance parameters have been extracted in the neutron energy range up to 8 keV, yielding capture widths smaller (14%) than reported in an earlier experiment. These results are important for detailed nucleosynthesis calculations and for refined studies of waste transmutation concepts.EC FIKW-CT-2000-0010

Quasicontinuum γ\gamma-decay of 91,92^{91,92}Zr: benchmarking indirect (n,γn,\gamma) cross section measurements for the ss-process

Nuclear level densities (NLDs) and $\gamma$-ray strength functions ($\gamma$SFs) have been extracted from particle-$\gamma$ coincidences of the $^{92}$Zr($p,p' \gamma$)$^{92}$Zr and $^{92}$Zr($p,d \gamma$)$^{91}$Zr reactions using the Oslo method. The new $^{91,92}$Zr $\gamma$SF data, combined with photonuclear cross sections, cover the whole energy range from $E_{\gamma} \approx 1.5$~MeV up to the giant dipole resonance at $E_{\gamma} \approx 17$~MeV. The wide-range $\gamma$SF data display structures at $E_{\gamma} \approx 9.5$~MeV, compatible with a superposition of the spin-flip $M1$ resonance and a pygmy $E1$ resonance. Furthermore, the $\gamma$SF shows a minimum at $E_{\gamma} \approx 2-3$~MeV and an increase at lower $\gamma$-ray energies. The experimentally constrained NLDs and $\gamma$SFs are shown to reproduce known ($n, \gamma$) and Maxwellian-averaged cross sections for $^{91,92}$Zr using the {\sf TALYS} reaction code, thus serving as a benchmark for this indirect method of estimating ($n, \gamma$) cross sections for Zr isotopes.Comment: 10 pages and 9 figure

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

The temperature and chronology of heavy-element synthesis in low-mass stars

Roughly half of the heavy elements (atomic mass greater than that of iron) are believed to be synthesized in the late evolutionary stages of stars with masses between 0.8 and 8 solar masses. Deep inside the star, nuclei (mainly iron) capture neutrons and progressively build up (through the slow-neutron-capture process, or s-process) heavier elements that are subsequently brought to the stellar surface by convection. Two neutron sources, activated at distinct temperatures, have been proposed: 13C and 22Ne, each releasing one neutron per alpha-particle (4He) captured. To explain the measured stellar abundances, stellar evolution models invoking the 13C neutron source (which operates at temperatures of about one hundred million kelvin) are favoured. Isotopic ratios in primitive meteorites, however, reflecting nucleosynthesis in the previous generations of stars that contributed material to the Solar System, point to higher temperatures (more than three hundred million kelvin), requiring at least a late activation of 22Ne. Here we report a determination of the s-process temperature directly in evolved low-mass giant stars, using zirconium and niobium abundances, independently of stellar evolution models. The derived temperature supports 13C as the s-process neutron source. The radioactive pair 93Zr-93Nb used to estimate the s-process temperature also provides, together with the pair 99Tc-99Ru, chronometric information on the time elapsed since the start of the s-process, which we determine to be one million to three million years.Comment: 30 pages, 10 figure

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

Measurement of the Spin-Dependence of the pbar-p Interaction at the AD-Ring

We propose to use an internal polarized hydrogen storage cell gas target in the AD ring to determine for the first time the two total spin-dependent pbar-p cross sections sigma_1 and sigma_2 at antiproton beam energies in the range from 50 to 450 MeV. The data obtained are of interest by themselves for the general theory of pbar-p interactions since they will provide a first experimental constraint of the spin-spin dependence of the nucleon-antinucleon potential in the energy range of interest. In addition, measurements of the polarization buildup of stored antiprotons are required to define the optimum parameters of a future, dedicated Antiproton Polarizer Ring (APR), intended to feed a double-polarized asymmetric pbar-p collider with polarized antiprotons. Such a machine has recently been proposed by the PAX collaboration for the new Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt, Germany. The availability of an intense stored beam of polarized antiprotons will provide access to a wealth of single- and double-spin observables, thereby opening a new window on QCD spin physics.Comment: 51 pages, 23 figures, proposal submitted to the SPS committee of CER

Spin tune mapping as a novel tool to probe the spin dynamics in storage rings

Precision experiments, such as the search for electric dipole moments of charged particles using storage rings, demand for an understanding of the spin dynamics with unprecedented accuracy. The ultimate aim is to measure the electric dipole moments with a sensitivity up to 15 orders in magnitude better than the magnetic dipole moment of the stored particles. This formidable task requires an understanding of the background to the signal of the electric dipole from rotations of the spins in the spurious magnetic fields of a storage ring. One of the observables, especially sensitive to the imperfection magnetic fields in the ring is the angular orientation of stable spin axis. Up to now, the stable spin axis has never been determined experimentally, and in addition, the JEDI collaboration for the first time succeeded to quantify the background signals that stem from false rotations of the magnetic dipole moments in the horizontal and longitudinal imperfection magnetic fields of the storage ring. To this end, we developed a new method based on the spin tune response of a machine to artificially applied longitudinal magnetic fields. This novel technique, called \textit{spin tune mapping}, emerges as a very powerful tool to probe the spin dynamics in storage rings. The technique was experimentally tested in 2014 at the cooler synchrotron COSY, and for the first time, the angular orientation of the stable spin axis at two different locations in the ring has been determined to an unprecedented accuracy of better than $2.8\mu$rad.Comment: 32 pages, 15 figures, 7 table

Phase Measurement for Driven Spin Oscillations in a Storage Ring

This paper reports the first simultaneous measurement of the horizontal and vertical components of the polarization vector in a storage ring under the influence of a radio frequency (rf) solenoid. The experiments were performed at the Cooler Synchrotron COSY in J\"ulich using a vector polarized, bunched $0.97\,\textrm{GeV/c}$ deuteron beam. Using the new spin feedback system, we set the initial phase difference between the solenoid field and the precession of the polarization vector to a predefined value. The feedback system was then switched off, allowing the phase difference to change over time, and the solenoid was switched on to rotate the polarization vector. We observed an oscillation of the vertical polarization component and the phase difference. The oscillations can be described using an analytical model. The results of this experiment also apply to other rf devices with horizontal magnetic fields, such as Wien filters. The precise manipulation of particle spins in storage rings is a prerequisite for measuring the electric dipole moment (EDM) of charged particles

Phase locking the spin precession in a storage ring

This letter reports the successful use of feedback from a spin polarization measurement to the revolution frequency of a 0.97 GeV/$c$ bunched and polarized deuteron beam in the Cooler Synchrotron (COSY) storage ring in order to control both the precession rate ($\approx 121$ kHz) and the phase of the horizontal polarization component. Real time synchronization with a radio frequency (rf) solenoid made possible the rotation of the polarization out of the horizontal plane, yielding a demonstration of the feedback method to manipulate the polarization. In particular, the rotation rate shows a sinusoidal function of the horizontal polarization phase (relative to the rf solenoid), which was controlled to within a one standard deviation range of $\sigma = 0.21$ rad. The minimum possible adjustment was 3.7 mHz out of a revolution frequency of 753 kHz, which changes the precession rate by 26 mrad/s. Such a capability meets a requirement for the use of storage rings to look for an intrinsic electric dipole moment of charged particles

Present Status and Future Programs of the n_TOF Experiment

This is an Open Access article distributed under the terms of the Creative Commons Attribution-Noncommercial License 3.0, which permits unrestricted use, distribution, and reproduction in any noncommercial medium, provided the original work is properly citedThe neutron time-of-flight facility n_TOF at CERN, Switzerland, operational since 2001, delivers neutrons using the Proton Synchrotron (PS) 20 GeV/c proton beam impinging on a lead spallation target. The facility combines a very high instantaneous neutron flux, an excellent time of flight resolution due to the distance between the experimental area and the production target (185 meters), a low intrinsic background and a wide range of neutron energies, from thermal to GeV neutrons. These characteristics provide a unique possibility to perform neutron-induced capture and fission cross-section measurements for applications in nuclear astrophysics and in nuclear reactor technology.The most relevant measurements performed up to now and foreseen for the future will be presented in this contribution. The overall efficiency of the experimental program and the range of possible measurements achievable with the construction of a second experimental area (EAR-2), vertically located 20 m on top of the n_TOF spallation target, might offer a substantial improvement in measurement sensitivities. A feasibility study of the possible realisation of the installation extension will be also presented