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  • 1.
    Adlarson, Patrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Study of the decay eta -> pi(+)pi(-)pi(0) with WASA-at-COSY2012In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T150, p. 014001-Article in journal (Refereed)
    Abstract [en]

    Recently, a large statistics sample of approximately 3 x 10(7) eta decays was collected with the Wide Angle Shower Apparatus (WASA) detector at COoler SYnchrotron (COSY) using the pd -> He-3 eta reaction at the proton kinetic energy of 1 GeV. These data are being used to study the not so rare eta decays involving charged pions, such as eta -> pi(+)pi(-)pi(0). This decay proceeds mainly via a strong isospin violating contribution, where the decay width is proportional to the light quark mass difference squared, (m(d) - m(u))(2). The status of the analysis is presented, which preliminarily gives 1.8 x 10(5) eta -> pi(+)pi(-)pi(0) candidates in the Dalitz plot.

  • 2. Ali, MP
    et al.
    Tove, PA
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Norde, Herman
    Junctions between amorphous and crystalline silicon1981In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 24, p. 339-400Article in journal (Refereed)
  • 3. Ali, MP
    et al.
    Tove, PA
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Stolt, Lars
    Barrier height of Fe contacts to Si1981In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 24, p. 408-409Article in journal (Refereed)
  • 4.
    Allen, Roland E.
    et al.
    Texas A&M Univ, Dept Phys & Astron, College Stn, TX 77843 USA..
    Lidström, Suzy
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics. Royal Swedish Acad Sci, Phys Scripta, SE-10405 Stockholm, Sweden..
    21st Century frontiers-a series of articles on current challenges and future opportunities Preface2017In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 92, no 1, article id 010302Article in journal (Refereed)
  • 5.
    Allen, Roland E.
    et al.
    Texas A&M Univ, Dept Phys & Astron, College Stn, TX 77843 USA..
    Lidström, Suzy
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics. Royal Swedish Acad Sci, Phys Scripta, SE-10405 Stockholm, Sweden..
    Life, the Universe, and everything: 42 fundamental questions2017In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 92, no 1, article id 012501Article in journal (Refereed)
    Abstract [en]

    In The Hitchhiker's Guide to the Galaxy, by Douglas Adams, the Answer to the Ultimate Question of Life, the Universe, and Everything is found to be 42 - but the meaning of this is left open to interpretation. We take it to mean that there are 42 fundamental questions which must be answered on the road to full enlightenment, and we attempt a first draft (or personal selection) of these ultimate questions, on topics ranging from the cosmological constant and origin of the Universe to the origin of life and consciousness.

  • 6. Allen, Roland E.
    et al.
    Lidström, Suzy
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Your Higgs number-how fundamental physics is connected to technology and societal revolutions2015In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 90, no 2, article id 028002Article in journal (Other academic)
    Abstract [en]

    Fundamental physics, as exemplified by the recently discovered Higgs boson, often appears to be completely disconnected from practical applications and ordinary human life. But this is not really the case, because science, technology, and human affairs are profoundly integrated in ways that are not immediately obvious. We illustrate this by defining a 'Higgs number' through overlapping activities. Following three different paths, which end respectively in applications of the World Wide Web, digital photography, and all modern electronic devices, we find that most people have a Higgs number of no greater than 3.

  • 7. Al-Zoubi, Noura
    et al.
    Li, Xiaoqing
    Schonecker, Stephan
    Johansson, Börje
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Vitos, Levente
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Influence of manganese on the bulk properties of Fe-Cr-Mn alloys: a first-principles study2014In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 89, no 12, p. 125702-Article in journal (Refereed)
    Abstract [en]

    We investigate the effect of manganese on lattice stability and magnetic moments of paramagnetic Fe-Cr-Mn steel alloys along the Bain path connecting the body-centered cubic (bcc) and face-centered cubic (fcc) structures. The calculations are carried out using the ab initio exact muffin-tin orbital method, in combination with the coherent potential approximation, and the paramagnetic phase is modeled by the disordered local magnetic moment scheme. For all Fe-Cr-Mn alloys considered here, the local magnetic moments on Fe atoms have the minimum values for the fcc structure and the maximum values for the bcc structure, whereas the local magnetic moments on Mn have almost the same value along the constant-volume Bain path. Our results show that Mn addition to paramagnetic Fe-Cr solid solution stabilizes the bcc structure. However, when considering the paramagnetic fcc phase relative to the ferromagnetic bcc ground state, then Mn turns out to be a clear fcc stabilizer, in line with observations.

  • 8.
    André, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Previously hidden low-energy ions: a better map of near-Earth space and the terrestrial mass balance2015In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 90, no 12, article id 128005Article in journal (Refereed)
    Abstract [en]

    This is a review of the mass balance of planet Earth, intended also for scientists not usually working with space physics or geophysics. The discussion includes both outflow of ions and neutrals from the ionosphere and upper atmosphere, and the inflow of meteoroids and larger objects. The focus is on ions with energies less than tens of eV originating from the ionosphere. Positive low-energy ions are complicated to detect onboard sunlit spacecraft at higher altitudes, which often become positively charged to several tens of volts. We have invented a technique to observe low-energy ions based on the detection of the wake behind a charged spacecraft in a supersonic ion flow. We find that low-energy ions usually dominate the ion density and the outward flux in large volumes in the magnetosphere. The global outflow is of the order of 10(26) ions s(-1). This is a significant fraction of the total number outflow of particles from Earth, and changes plasma processes in near-Earth space. We compare order of magnitude estimates of the mass outflow and inflow for planet Earth and find that they are similar, at around 1 kg s(-1) (30 000 ton yr(-1)). We briefly discuss atmospheric and ionospheric outflow from other planets and the connection to evolution of extraterrestrial life.

  • 9.
    Aydin, Alhun
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. Nano Energy Research Group, Energy Institute, Istanbul Technical University, 34469, Istanbul, Turkey.
    Oikonomou, Thomas
    Bagci, Gokhan Baris
    Sisman, Altug
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. Nano Energy Research Group, Energy Institute, Istanbul Technical University, 34469, Istanbul, Turkey.
    Discrete and Weyl density of states for photonic dispersion relation2019In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 94, no 10, article id 105001Article in journal (Refereed)
    Abstract [en]

    The current density of states (DOS) calculations do not take into account the essential discretenessof the state space, since they rely on the unbounded continuum approximation. Recently, discrete DOS based on the quantum-mechanically allowable minimum energy interval has been introducedfor quadratic dispersion relation. In this work, we consider systems exhibiting photonic (photon-like) dispersion relation and calculate the related density and number of states (NOS). Also, a Weyl's conjecture-based DOS function is calculated for photons and acoustic phonons at low frequency limit,by considering the bounded continuum approach. We show that discrete DOS function reducesto expressions of bounded and unbounded continua in the appropriate limits. The uctuationsin discrete DOS completely disappear under accumulation operators. It's interesting that relativeerrors of NOS and DOS functions with respect to discrete ones have exactly the same character withthe ones of quadratic dispersion relation. Furthermore, the application of discrete and Weyl DOS for the calculation of internal energy of a photon gas is presented and importance of discrete DOSis discussed. It's shown that discrete DOS function given in this work needs to be used wheneverthe low energy levels of a physical system are heavily occupied.

  • 10.
    Aydin, Alhun
    et al.
    Istanbul Technical University, Energy Institute.
    Sisman, Altug
    Istanbul Technical University, Energy Institute.
    Dimensional transitions in thermodynamic properties of ideal Maxwell-Boltzmann gases2015In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 90, article id 045208Article in journal (Refereed)
    Abstract [en]

    An ideal Maxwell–Boltzmann gas confined in various rectangular nanodomains is considered underquantum size effects. Thermodynamic quantities are calculated from their relations with the partitionfunction, which consists of triple infinite summations over momentum states in each direction. Toobtain analytical expressions, summations are converted to integrals for macrosystems by acontinuum approximation, which fails at the nanoscale. To avoid both the numerical calculation ofsummations and the failure of their integral approximations at the nanoscale, a method which gives ananalytical expression for a single particle partition function (SPPF) is proposed. It is shown that adimensional transition in momentum space occurs at a certain magnitude of confinement. Therefore,to represent the SPPF by lower-dimensional analytical expressions becomes possible, rather thannumerical calculation of summations. Considering rectangular domains with different aspect ratios, acomparison of the results of derived expressions with those of summation forms of the SPPF is made.It is shown that analytical expressions for the SPPF give very precise results with maximum relativeerrors of around 1%, 2% and 3% at exactly the transition point for single, double and triple transitions,respectively. Based on dimensional transitions, expressions for free energy, entropy, internal energy,chemical potential, heat capacity and pressure are given analytically valid for any scale.

  • 11. Azofeifa, D. E.
    et al.
    Clark, N.
    Vargas, W. E.
    Solis, H.
    Palsson, G. K.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Hjorvarsson, B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Temperature-and hydrogen-induced changes in the optical properties of Pd capped V thin films2012In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 86, no 6, p. 065702-Article in journal (Refereed)
    Abstract [en]

    Optical properties of V thin films deposited on MgO substrates have been obtained from spectrophotometric measurements. The V films were coated with a thin Pd layer to protect them from oxidation and to favor absorption of atomic hydrogen. Electrical resistance was recorded while hydrogen pressure was increased slowly up to 750mbar keeping the temperature constant. Simultaneously, visible and near-infrared transmittance spectra of this Pd/V/MgO system were measured. The spectra were numerically inverted to obtain the spectral behavior of the Pd and V dielectric functions at 22 and 140 degrees C. Hydrogen concentrations were first determined from the combined effect of hydrogen content on the electrical resistance and on the optical direct transmission of the system. Then, determination of these concentrations was improved using retrieved values of the absorption coefficients of the hydrides and taking into account the structural change of V and the volumetric expansion of Pd. Good agreement is established when considering qualitative correlations between spectral features of the optimized PdHy and VHx dielectric functions and band structure calculations and densities of states for these two transition metal hydrides.

  • 12.
    Barklem, Paul S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Hydrogen lines2008In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T133, p. 014023-Article in journal (Refereed)
    Abstract [en]

    Advances in modern detectors have allowed hydrogen Balmer lines to be used as high-precision diagnostics of effective temperature in F, G and K stars. Their precision as such a diagnostic is now to a large degree dependent on our understanding of their formation in stellar atmospheres. In this paper, I review the current status of Balmer lines as effective temperature diagnostics and in particular discuss two aspects of their line formation: (i) the question of whether the line wings form in Local Thermodynamic Equilibrium (LTE) or not and (ii) the broadening of the line wings by collisions.

  • 13.
    Bergsaker, H.
    et al.
    EUROfus Consortium, JET, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England.;KTH Royal Inst Technol, Sch Elect Engn, Dept Fus Plasma Phys, SE-10405 Stockholm, Sweden..
    Bykov, I.
    EUROfus Consortium, JET, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England.;KTH Royal Inst Technol, Sch Elect Engn, Dept Fus Plasma Phys, SE-10405 Stockholm, Sweden..
    Zhou, Y.
    EUROfus Consortium, JET, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England.;KTH Royal Inst Technol, Sch Elect Engn, Dept Fus Plasma Phys, SE-10405 Stockholm, Sweden..
    Petersson, P.
    EUROfus Consortium, JET, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England.;KTH Royal Inst Technol, Sch Elect Engn, Dept Fus Plasma Phys, SE-10405 Stockholm, Sweden..
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory. EUROfus Consortium, JET, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Likonen, J.
    EUROfus Consortium, JET, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England.;VTT Tech Res Ctr Finland, POB 1000, FI-02044 Espoo, Finland..
    Pettersson, Jean
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry. EUROfus Consortium, JET, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Koivuranta, S.
    EUROfus Consortium, JET, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England.;VTT Tech Res Ctr Finland, POB 1000, FI-02044 Espoo, Finland..
    Widdowson, A. M.
    EUROfus Consortium, JET, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England.;CCFE, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Deep deuterium retention and Be/W mixing at tungsten coated surfaces in the JET divertor2016In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T167, article id 014061Article in journal (Refereed)
    Abstract [en]

    Surface samples from a full poloidal set of divertor tiles exposed in JET through operations 2010-2012 with ITER-like wall have been investigated using SEM, SIMS, ICP-AES analysis and micro beam nuclear reaction analysis (mu-NRA). Deposition of Be and retention of D is microscopically inhomogeneous. With careful overlaying of mu-NRA elemental maps with SEM images, it is possible to separate surface roughness effects from depth profiles at microscopically flat surface regions, without pits. With (He-3, p) mu-NRA at 3-5 MeV beam energy the accessible depth for D analysis in W is about 9 mu m, sufficient to access the W/Mo and Mo/W interfaces in the coatings and beyond, while for Be in W it is about 6 mu m. In these conditions, at all plasma wetted surfaces, D was found throughout the whole accessible depth at concentrations in the range 0.2-0.7 at% in W. Deuterium was found to be preferentially trapped at the W/Mo and Mo/W interfaces. Comparison is made with SIMS profiling, which also shows significant D trapping at the W/Mo interface. Mixing of Be and W occurs mainly in deposited layers.

  • 14.
    Bläckberg, Lisa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Klintenberg, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Ringbom, Anders
    Sjöstrand, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Effects of surface coatings on the light collection in plastic scintillators used for radioxenon detection2012In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T150, p. 014007-Article in journal (Refereed)
    Abstract [en]

    Atomic Layer Deposition coatings are under investigation to reduce diffusion of radioxenon into plastic scintillators. This paper investigates the impact of such surface coating on the light collection efficiency in a cylindrical geometry. A high and uniform light collection efficiency is important to preserve detector resolution. Monte Carlo simulations and measurements have been performed to study the influence of coating thickness, refractive index, and surface quality. It was found important to achieve a smooth coating, and a good optical match between the refractive indices of the coating and the plastic scintillator. Taking these considerations into account, the detector under study could be coated without significant degradation of its resolution.

  • 15. Boberg, G
    et al.
    Stolt, Lars
    Tove, PA
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Norde, Herman
    Contact resistance measurements on platinum-silicide and chromium contacts to highly doped n and p silicon1981In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 24, p. 405-407Article in journal (Refereed)
  • 16.
    de Sousa Pires, Jorge
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    A correction diagram for the photoelectric measurement of MS barrier heights1978In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 18, p. 372-Article in journal (Refereed)
  • 17. De Temmerman, G.
    et al.
    Doerner, R. P.
    John, P.
    Lisgo, S.
    Litnovsky, A.
    Marot, L.
    Porro, S.
    Petersson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Rubel, M.
    Rudakov, D. L.
    Van Rooij, G.
    Westerhout, J.
    Wilson, J. I. B.
    Interactions of diamond surfaces with fusion relevant plasmas2009In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T138, p. 014013-Article in journal (Refereed)
  • 18. Drugge, B
    et al.
    Nordlander, E
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Edlund, P
    Laser scanning technique for the detection of minority carrier lifetime inhomogeneities in silicon using liquid rectifying contacts1981In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 24, p. 392-395Article in journal (Refereed)
  • 19.
    Edvardsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Astronomy and Space Physics.
    Observed versus predicted stellar flux distributions of solar-type stars2008In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T133, p. 014011-Article in journal (Refereed)
    Abstract [en]

    I have compared the low-resolution spectrophotometric fluxes in the visible spectral region of F- and G-type MARCS 2008 model atmospheres to six spectrophotometric databases of the Sun and stars. These observational databases disagree with each other concerning the overall red/blue flux balances on the several percent scale for the same objects. There is, however, no systematic overall trend between MARCS model fluxes and these observations taken together and therefore no reason to suspect any problem with the MARCS overall spectrum balance. The results strongly suggest, however, that there are systematic errors in the ultraviolet and blue opacities used in the construction of the model atmospheres. These errors appear in wavelength regions with widths of some 50-150 angstrom. Similar uncertainties are found also in other independent libraries of synthetic model atmosphere fluxes. I also highlight a number of unidentified spectral features with unusual shapes in spectra of the Sun and solar-type stars.

  • 20. Engström, O
    et al.
    Drugge, B
    Tove, PA
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Laser scanning technique for the detection of resistivity and lifetime inhomogeneities in semiconductior devices or photon scanning applied to silicon for determination of bulk properties1978In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 18, p. 357-Article in journal (Refereed)
  • 21.
    Eriksson, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Astronomy and Space Physics.
    CNO abundances in carbon star atmospheres-a progress report2008In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T133, p. 014029-Article in journal (Refereed)
    Abstract [en]

    A brief progress report is given on an on-going project to estimate the C, N and O abundances in carbon stars of the Magellanic Cloud clusters NGC 1846 and NGC 419. The changes in these abundances as a function of position along the asymptotic giant branch (AGB) are sought for.

  • 22.
    Firat, Coskun
    et al.
    Istanbul Technical University, Energy Institute.
    Sisman, Altug
    Istanbul Technical University, Energy Institute.
    Quantum Forces of a gas confined in nano structures2013In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 87, article id 045008Article in journal (Refereed)
    Abstract [en]

    In nano domains, thermodynamic properties of gases considerably differ from those in macrodomains. One of the reasons for this difference is the quantum size effects, which becomeimportant when the thermal de Broglie wavelength of particles is not negligible in comparisonwith domain size. In this study, it is shown that quantum forces may appear in gases confinedin nano structures due to the quantum boundary layer caused by quantum size effects. In thecase of experimental verification of these quantum forces, a macroscopic manifestation of theeffect of the quantum boundary layer on the thermodynamic behavior of gases can beconfirmed.

  • 23.
    Firat, Coskun
    et al.
    Istanbul Technical University, Energy Institute.
    Sisman, Altug
    Istanbul Technical University, Energy Institute.
    Universality of the quantum boundary layer for a Maxwellian gas2009In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 79, article id 065002Article in journal (Refereed)
    Abstract [en]

    For an ideal gas confined in a rectangular domain, it has been shown that the density is not homogenous even in thermodynamic equilibrium and it goes to zero within a layernear to the boundaries due to the wave character of particles. This layer has been called the quantum boundary layer (QBL). In literature, an analytical expression for the thickness of QBL has been given for only a rectangular domain since both energy eigenvalues andeigenfunctions of the Schrödinger equation can analytically be obtained for only a rectangulardomain. In this study, ideal Maxwellian gases confined in spherical and cylindrical domainsare considered to investigate whether the thickness of QBL is independent of the domain shape. Although the energy eigenvalues are the roots of Bessel functions and there is noanalytical expression giving the roots, the thickness of QBL is expressed analytically by considering the density distributions and using some simplifications based on the numerical calculations. It is found that QBL has the same thickness for the domains of different shapes.Therefore, QBL seems to have a universal thickness independent of the domain shape for anideal Maxwellian gas.

  • 24. Fortuna-Zalesna, E.
    et al.
    Weckmann, Armin
    KTH, Fusionsplasmafysik.
    Grozonka, J.
    Rubel, Marek
    KTH, Fusionsplasmafysik.
    Esser, H. G.
    Freisinger, M.
    Kreter, A.
    Kischner, A.
    Sergienko, G.
    Ström, Petter
    KTH, Fusionsplasmafysik.
    Dust Survey Following the Final Shutdown of TEXTOR: Metal Particles and Fuel Retention2016In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T167, article id 014059Article in journal (Refereed)
    Abstract [en]

    The work presents results of a broad TEXTOR dust survey in terms of its composition, structure, distribution and fuel content. The dust particles were collected after final shutdown of TEXTOR in December 2013. Fuel retention, as determined by thermal desorption, varied significantly, even by two orders of magnitude, dependent on the dust location in the machine. Dust structure was examined by means of scanning electron microscopy combined with energy-dispersive X-ray spectroscopy, focused ion beam and scanning transmission electron microscopy. Several categories of dust have been identified. Carbon-based stratified and granular deposits were dominating, but the emphasis in studies was on metal dust. They were found in the form of small particles, small spheres, flakes and splashes which formed “comet”-like structures clearly indicating directional effects in the impact on surfaces of plasma-facing components. Nickel-rich alloys from the Inconel liner and iron-based ones from various diagnostic holders were the main components of metal-containing dust, but also molybdenum and tungsten debris were detected. Their origin is discussed.

  • 25.
    Gelin, B
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Parallel plate muyltichannel electron detector with uniform response1982In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 24, p. 4484-Article in journal (Refereed)
  • 26.
    Gustafsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Astronomy and Space Physics.
    Is the Sun unique as a star - and if so, why?2008In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T130, p. 014036-Article in journal (Refereed)
    Abstract [en]

    The question whether the Sun is peculiar as compared with other stars in its neigbourhood is revisited. It is concluded that although the Sun is rather normal from many points of view, it departs in several respects from most stars of similar age and galactic orbit. Thus, it is more massive, and the amplitude of the micro-variability of the Sun at visual wavelengths seems unusually small. It also departs from most stars in being a single star, and it may have an unusual planetary system. There are some tentative indications that its chemical composition departs from those of most solar-type stars of similar age. This is discussed and the departures are found not to be significant. I discuss here to what extent these peculiarities may be understood in terms of it being a planet host.

  • 27.
    Gustavsson, Cecilia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Scian, Giovanni
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lecolley, F-R
    Tippawan, U
    Watanabe, Y
    Nuclear data measurements at the new NFS facility at GANIL2012In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 2012, no T150, p. 014017-Article in journal (Refereed)
    Abstract [en]

    The NFS (Neutrons For Science) facility is part of the SPRIAL 2 project at GANIL, Caen, France. The facility is currently under construction and the first beam is expected in early 2013. NFS will have a white neutron source covering the 1–40 MeV energy range with a neutron flux higher than comparable facilities. A quasi-mono-energetic neutron beam will also be available. In these energy ranges, especially above 14 MeV, there is a large demand for neutron-induced data for a wide range of applications involving dosimetry, medical therapy, single-event upsets in electronics and nuclear energy. Today, there are a few or no cross section data on reactions such as (n, fission), (n, xn), (n, p), (n, d) and (n, α ). We propose to install experimental equipment for measuring neutron-induced light-charged particle production and fission relative to the H(n, p) cross section. Both the H(n, p) cross section and the fission cross section for 238 U are important reference cross sections used as standards for many other experiments. Nuclear data for certain key elements, such as closed shell nuclei, are also of relevance for the development of nuclear reaction models. Our primary intention is to measure charged particle production (protons, deuterons and alphas) from 12 C, 16 O, 28 Si and 56 Fe and neutron-induced fission cross sections from 238 U and 232 Th.

  • 28.
    Heiter, Ulrike
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Lind, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Asplund, M.
    Barklem, Paul S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Bergemann, M.
    Magrini, L.
    Masseron, T.
    Mikolaitis, S.
    Pickering, J. C.
    Ruffoni, M. P.
    Atomic and molecular data for optical stellar spectroscopy2015In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 90, no 5, article id 054010Article in journal (Refereed)
    Abstract [en]

    High-precision spectroscopy of large stellar samples plays a crucial role for several topical issues in astrophysics. Examples include studying the chemical structure and evolution of the Milky Way Galaxy, tracing the origin of chemical elements, and characterizing planetary host stars. Data are accumulating from instruments that obtain high-quality spectra of stars in the ultraviolet, optical and infrared wavelength regions on a routine basis. These instruments are located at ground-based 2-10 m class telescopes around the world, in addition to the spectrographs with unique capabilities available at the Hubble Space Telescope. The interpretation of these spectra requires high-quality transition data for numerous species, in particular neutral and singly ionized atoms, and di-or triatomic molecules. We rely heavily on the continuous efforts of laboratory astrophysics groups that produce and improve the relevant experimental and theoretical atomic and molecular data. The compilation of the best available data is facilitated by databases and electronic infrastructures such as the NIST Atomic Spectra Database, the VALD database, or the Virtual Atomic and Molecular Data Centre. We illustrate the current status of atomic data for optical stellar spectra with the example of the Gaia-ESO Public Spectroscopic Survey. Data sources for 35 chemical elements were reviewed in an effort to construct a line list for a homogeneous abundance analysis of up to 10(5) stars.

  • 29.
    Heiter, Ulrike
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Astronomy and Space Physics.
    Luck, R. E.
    How unique is the local region of the Galaxy disk?2008In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T133, p. 014040-Article in journal (Refereed)
    Abstract [en]

    We present the results of a spectroscopic study of over 500 dwarf and giant stars within 100 pc of the Sun. Using stellar metallicity data, the goal of this study is to determine whether there are any significant variations of metallicity related to stellar characteristics or location in the Galaxy. The abundance data are based on high-resolution spectroscopy and correlated with kinematical properties based on Hipparcos data. The spectroscopic data are made available to the public through an online database. We find that most elements behave as expected from Galactic chemical evolution and are consistent with standard stellar evolution. Interesting trends are found for some elements, e. g. Mn and probably Ba. There is evidence for systematic carbon abundance variations in the red giant clump. To determine the uniqueness of the local region, in particular at its galactocentric radius, one should consider in-depth spectroscopic and kinematic studies of dwarfs and giants in similar-sized volumes in other regions of the disc. This will require accurate positions, distances and space motions out to hundreds of parsecs from space missions such as Gaia and next-generation telescopes for high-resolution spectroscopy.

  • 30.
    Hesselbom, H
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Helium ion backscattering analysis employed to study surface damage and contamination of RF sputter etched silicon1978In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 18, p. 400-Article in journal (Refereed)
  • 31.
    Hobein, Matthias
    et al.
    Stockholms universitet, Fysikum.
    Liu, Yanfang
    Stockholms universitet, Fysikum.
    Solders, Andreas
    Stockholms universitet, Fysikum.
    Suhonen, Markus
    Stockholms universitet, Fysikum.
    Kamalou, Omar
    Stockholms universitet, Fysikum.
    Schuch, Reinhold
    Stockholms universitet, Fysikum.
    A compact time-resolving pepperpot emittance meter for low-energy highly charged ions2011In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T144, p. 014062-Article in journal (Refereed)
    Abstract [en]

    An emittance meter for pulsed, low-energy ion beams was developed. Based on the pepperpot method, the device is compact and portable. It has been installed at the S-EBIT Laboratory at AlbaNova, Stockholm University, to measure the emittance of highly charged ions extracted from the electron beam ion trap R-EBIT and the cooling trap of the high-precision Penning trap mass spectrometer SMILETRAP II. Using a fast delay-line anode detector, the emittance and time-of-flight of the extracted ions can be measured simultaneously. In this paper, design and data processing system are described and preliminary results are presented.

  • 32.
    Höfner, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Astronomy and Space Physics.
    Winds of AGB stars: does size matter?2008In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T133, p. 014007-Article in journal (Refereed)
    Abstract [en]

    Asymptotic giant branch (AGB) stars are showing clear signs of significant mass loss through cool stellar winds. These outflows are attributed to the combined effects of pulsation-induced shocks and radiation pressure on dust grains formed in the outer atmospheric layers. This paper gives an overview of the current status of radiation-hydrodynamical modelling of these processes, and presents a toy model that allows analysis of certain features of detailed models, such as the influence of grain size dependent opacities and basic differences in winds of C- and M-type AGB stars.

  • 33. Ivanova, D.
    et al.
    Rubel, M.
    Philipps, V.
    Schweer, B.
    Petersson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Freisinger, M.
    Schmidt, A.
    Fuel re-absorption by thermally treated co-deposited carbon layers2011In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, no T145, p. 014006-Article in journal (Refereed)
    Abstract [en]

    Systematic studies have been conducted to address the fuel re-absorption by carbon deposits under repeated exposure to plasma after cleaning procedures. The investigation was done with graphite tiles from ALT-II (Advanced Limiter Test II), i.e. the main limiter at the TEXTOR tokamak. Pure graphite plates were used as the reference material. The experimental programme comprised the following: pre-characterization of specimens; D desorption by baking the tile at 1273 K; surface analyses of the fuel-depleted layers; exposure to deuterium in a laboratory plasma device and in TEXTOR; and quantitative assessment of deuterium re-absorption. The main result is that fuel retention in the re-exposed deposits is 30-40 times lower than that in the original co-deposit, showing that fuel re-absorption does not lead to an immediate re-saturation of deposits. Annealing at high temperatures enhances layer brittleness, leading eventually to detachment of co-deposits.

  • 34. Kalvius, G. M.
    et al.
    Hartmann, Ola
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Wäppling, Roger
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Noakes, D. R.
    Schaefer, W.
    A mu SR study of the magnetic properties of Tb2CuIn32013In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 87, no 5, p. 055702-Article in journal (Refereed)
    Abstract [en]

    Tb2CuIn3 shows exceptional magnetic behavior within the series of R2CuIn3 intermetallics (R denoting one of the rare earth elements), where long-range magnetic order is absent in favor of spin liquid magnetic ground states as a consequence of frustration by competing exchange. In contrast, neutron studies suggested for the magnetic ground state of Tb2CuIn3 the coexistence of long-range antiferromagnetic and short-range order. The present mu SR (muon spin rotation/relaxation) data show that at similar to 45K all Tb magnetic moments freeze into a spin-glass state. At T-N = 33K partial long-range order sets in, its volume fraction being similar to 30%. On cooling to 10 K, the antiferromagnetic fraction reaches the saturation value of 70% and hence remains coexistent with the spin-glass state for T -> 0. The antiferromagnetic state is characterized by considerable short-range spin disorder. At low temperatures the Tb moments in the two coexisting states approach the static limit. This absence of persistent moment fluctuations together with partial formation of long-range order indicates considerably lower frustration in Tb2CuIn3 compared to the rest of the R2CuIn3 compounds.

  • 35. Kalvius, G. M.
    et al.
    Hartmann, Ola
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Wäppling, Roger
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Noakes, D. R.
    Schaefer, W.
    Magnetism of frustrated R2TIn3 compounds (R = Nd, Ho, Er; T = Ag, Cu) by muon spin rotation2013In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 88, no 4, p. 045702-Article in journal (Refereed)
    Abstract [en]

    Several R2TIn3 samples (Nd2AgIn3, Ho2AgIn3, Er2AgIn3, Ho2CuIn3 and Er2CuIn3 were studied by muon spin rotation/relaxation (mu SR). The R2TIn3 intermetallics are magnetically frustrated, mainly by competing ferro- and antiferromagnetic exchange. Susceptibility data suggested antiferromagnetic order with T-N in the 10K range for the materials under consideration. Later neutron diffraction studies were, however, unable to detect any magnetic Bragg peaks. The mu SR spectra of all compounds consist of two signals. One fast relaxing, reflecting strong interaction between the muon and the rare earth magnetic moments, the other slowly relaxing, arising largely from the interaction with the nuclear moments of In, its coupling to rare earth magnetism being extremely weak. Suggested origin are two different muon stopping sites in the binary layered crystal structure of the R2TIn3 series. Results on the magnetic behavior of the compounds studied are drawn from the fast relaxing signal. They show that below the susceptibility peak temperatures the systems enter into a spin-glass-type (Nd) or a spin-liquid-type (Ho,Er) short-range ordered magnetic structures, long-range order being definitely absent. Spin fluctuations persist in all cases in the limit T -> 0, a well established mu SR signature for frustrated magnetic materials.

  • 36. Kalvius, G. M.
    et al.
    Noakes, D. R.
    Wäppling, Roger
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics III.
    Marcano, N.
    Schreier, E.
    Hartman, Ola
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics III.
    Rössler, U. K.
    Nenkov, K.
    Müller, K-H
    Idzikowski, B.
    Study of magnetic clusters in granular CoxCu1- x2008In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 77, no 2, p. 025705-Article in journal (Refereed)
    Abstract [en]

    Samples of CoxCu1-x (x = 0.05, 0.02 and 0.01) produced by melt spinning and subsequent annealing were studied by muon spin rotation/relaxation (mu SR) spectroscopy with the aim to gain information on the dependence of the local magnetic properties like the magnitude, the distribution and the temporal behavior of the magnetic field at the muon site as function of Co concentration. In addition, we investigated for Co0.02Cu0.98 the changes in mu SR response as function of annealing times and temperatures. In all alloys, a spin-glass-like magnetic cluster state was seen well below the susceptibility cusp temperature. Above this temperature, cluster spin dynamics sets in but with low fluctuation rates even at high temperatures reflecting the presence of strong cluster - cluster couplings. A free paramagnetic cluster state is not formed. Spin dynamic properties are different for the x = 0(05 and 0.02 compounds and the x = 0(01 alloy. In the former compounds, the coexistence of a slower and a faster fluctuating fraction is found, arising from a non-uniform cluster size distribution or a non-random spatial distribution of clusters. In the latter compound, the spin dynamical state is homogeneous, but shows an unusual mu SR response requiring the presence of simultaneous fluctuations in spin orientation and moment magnitude. It further points to the presence of a partial loss of magnetic clusters. The variation of annealing times and temperatures for Co0.02Cu0.98 influences details of mu SR spectral parameters but leaves the overall response the same.

  • 37.
    Karabetoglu, Sevan
    et al.
    Istanbul Technical University, Energy Institute.
    Sisman, Altug
    Istanbul Technical University, Energy Institute.
    An analytical solution for quantum size effects on Seebeck coefficient2016In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 91, article id 035803Article in journal (Refereed)
    Abstract [en]

    There are numerous experimental and numerical studies about quantum size effects on Seebeckcoefficient. In contrast, in this study, we obtain analytical expressions for Seebeck coefficientunder quantum size effects. Seebeck coefficient of a Fermi gas confined in a rectangular domainis considered. Analytical expressions, which represent the size dependency of Seebeckcoefficient explicitly, are derived in terms of confinement parameters. A fundamental form ofSeebeck coefficient based on infinite summations is used under relaxation time approximation.To obtain analytical results, summations are calculated using the first two terms of Poissonsummation formula. It is shown that they are in good agreement with the exact results based ondirect calculation of summations as long as confinement parameters are less than unity. Theanalytical results are also in good agreement with experimental and numerical ones in literature.Maximum relative errors of analytical expressions are less than 3% and 4% for 2D and 1D cases,respectively. Dimensional transitions of Seebeck coefficient are also examined. Furthermore, adetailed physical explanation for the oscillations in Seebeck coefficient is proposed byconsidering the relative standard deviation of total variance of particle number in Fermi shell.

  • 38.
    Karimipour, Masoud
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Wikberg, J. Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Kapaklis, Vassilios
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Shahtahmasebi, Nasser
    Dept of Physic, Faculty of Basic Science, and, Nanotechnology Laboratory, Nano Research Center, Ferdowsi University, Mashhad, Iran.
    Abad, Mahmood Rezaee Rokn
    Dept of Physic, Faculty of Basic Science, and, Nanotechnology Laboratory, Nano Research Center, Ferdowsi University, Mashhad, Iran.
    Yeganeh, Mahboubeh
    Dept of Physic, Faculty of Basic Science, and, Nanotechnology Laboratory, Nano Research Center, Ferdowsi University, Mashhad, Iran.
    Bagheri-Mohagheghi, M M
    School of Pphysics, Damghan University, Damghan, Iran.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Nanoparticles of Ni/NiO embedded in TiO(2) synthesized by the complex-polymer sol-gel method2011In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 84, no 3, p. 035702-Article in journal (Refereed)
    Abstract [en]

    Ni-doped TiO(2) nanoparticles were synthesized by the non-hydrous complex-polymer sol-gel method. Titanium isopropoxide was used as precursor and acetyl acetone (AcAc) and citric acid were used as polymer and complex agent, respectively. A series of Ni(x) : Ti(1-x)O(2) samples with x = 0.01, 0.03, 0.05 and 0.10 were prepared and subsequently annealed at 400, 600 and 800 degrees C. The structural and magnetic properties of Ni(x) : Ti(1-x)O(2) were studied by means of x-ray diffraction (XRD) and dc magnetometery. Samples annealed at 400 degrees C attained a particle size of 12 nm with structural phases of anatase, rutile and cubic NiO. From the blocking temperatures of the zero-field-cooled and field-cooled measurements, similar particle sizes (as from XRD) were obtained. The presence of ferro- and antiferromagnetic (AFM) interactions further confirms that the particles have different structural compositions. At 800 degrees C the particles have grown to about 30 nm with either a rutile or NiTiO(3)-type structure. The presence of NiTiO(3) is also seen in the magnetic measurements, which show the characteristic AFM peak at 23 K.

  • 39.
    Karlsson, Erik B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Materials Physics.
    Coherent proton and deuteron states in neutron scattering2008In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 77, no 6, p. 065301-Article in journal (Refereed)
    Abstract [en]

    Neutron Compton scattering has been used for a long time as a method to obtain information about proton momentum distributions in organic molecules, metal hydrides, etc. However, in a number of recent papers it has been shown that scattering on protons (and to some extent also on deuterons) shows intensities that are much smaller than expected when compared to those of the other constituents of the measured systems. This has raised the question if the Compton scattering process is fully understood (do, for instance, electron excitations take up part of the recoil energy and momentum?) and casts doubts on the reliability of the method for its original purpose. The present paper presents a detailed explanation for the intensity deficits in a number of studied systems without involving any participation of a third body in the scattering process. It is a development of an earlier proposed model, in which the intensity loss is caused by destructive interference in the waves representing the scattered neutron and the recoiling particle. These interferences appear when the scattering particles are indistinguishable (and therefore in a quantum superposition state) when seen by the neutron. It requires that the neutron coherence length (which is determined by the energy selection) is comparable to the internuclear distances. It is shown that the latter condition is at least partially fulfilled for two, three or four particles in the experiments and that it is likely that the necessary coherence remains over the very short duration (femtosecond (fs)) of the scattering process. Quantitative agreement is obtained for several proton and deuteron containing systems, including the observed dependence of the intensity deficit on scattering angle, which is explained in terms of the actual recoil energy as related to the proton- or deuteron-binding energy in the different systems. The question of available final states for the scattering system is discussed.

  • 40.
    Karlsson, Erik B
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    The hydrogen anomaly problem in neutron Compton scattering2018In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 93, no 3, article id 035801Article in journal (Refereed)
    Abstract [en]

    Neutron Compton scattering (also called 'deep inelastic scattering of neutrons', DINS) is a method used to study momentum distributions of light atoms in solids and liquids. It has been employed extensively since the start-up of intense pulsed neutron sources about 25 years ago. The information lies primarily in the width and shape of the Compton profile and not in the absolute intensity of the Compton peaks. It was therefore not immediately recognized that the relative intensities of Compton peaks arising from scattering on different isotopes did not always agree with values expected from standard neutron cross-section tables. The discrepancies were particularly large for scattering on protons, a phenomenon that became known as 'the hydrogen anomaly problem'. The present paper is a review of the discovery, experimental tests to prove or disprove the existence of the hydrogen anomaly and discussions concerning its origin. It covers a twenty-year-long history of experimentation, theoretical treatments and discussions. The problem is of fundamental interest, since it involves quantum phenomena on the subfemtosecond time scale, which are not visible in conventional thermal neutron scattering but are important in Compton scattering where neutrons have two orders of magnitude times higher energy. Different H-containing systems show different cross-section deficiencies and when the scattering processes are followed on the femtosecond time scale the cross-section losses disappear on different characteristic time scales for each H-environment. The last section of this review reproduces results from published papers based on quantum interference in scattering on identical particles (proton or deuteron pairs or clusters), which have given a quantitative theoretical explanation both regarding the H-cross-section reduction and its time dependence. Some new explanations are added and the concluding chapter summarizes the conditions for observing the specific quantum phenomena observed in neutron Compton scattering on protons and deuterons in condensed systems.

  • 41.
    Korn, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    NLTE line formation2008In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T133, p. 014009-Article in journal (Refereed)
    Abstract [en]

    I review some of the present achievements and future challenges of non-local thermodynamicequilibrium (NLTE) line-formation calculations for solar-type stars. It is concluded that thefull potential of NLTE still remains to be tapped, in particular in view of the current transitionfrom one-dimensional (1D) hydrostatic to 3D hydrodynamic model atmospheres.

  • 42. Kreter, A.
    et al.
    Baldwin, M. J.
    Doerner, R. P.
    Nishijima, D.
    Petersson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Pospieszczyk, A.
    Rubel, M.
    Umstadter, K.
    Fuel retention in carbon materials under ITER-relevant mixed species plasma conditions2009In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T138, p. 014012-Article in journal (Refereed)
  • 43.
    Lantz, Mattias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorelov, Dmitry
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Penttila, Heikki
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rados, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Ryzhov, Igor
    Design of a neutron converter for fission studies at the IGISOL facility2012In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T150, p. 014020-Article in journal (Refereed)
    Abstract [en]

    The upgraded IGISOL facility with JYFLTRAP, at the accelerator laboratory of the University of Jyvaskyla, has been supplied with a new cyclotron which will provide proton or deuteron beams of the order of 100 mu A with up to 30 MeV energy. This makes it an ideal place for measurements of neutron-induced fission fragments from various actinides, in view of proposed future nuclear fuel cycles. In the present paper, some considerations for the design of a neutron converter, based on simulations with the Monte Carlo codes MCNPX and FLUKA, are described.

  • 44.
    Lidström, Suzy
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics. Royal Swedish Acad Sci, Phys Scripta, Stockholm, Sweden..
    Allen, Roland E.
    Texas A&M Univ, Dept Phys & Astron, College Stn, TX 77843 USA..
    The unique advantages of and requirements for publishing in Physica Scripta2016In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 91, no 1, article id 010401Article in journal (Other academic)
  • 45.
    Litsarev, M. S.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Shevelko, V. P.
    Multiple-electron losses of highly charged ions colliding with neutral atoms2013In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T156, p. 014037-Article in journal (Refereed)
    Abstract [en]

    We present calculations of the total and m-fold electron-loss cross sections using the DEPOSIT code for highly charged Uq+ ions (q = 10, 31, 33) colliding with Ne and Ar targets at projectile energies E = 1.4 and 3.5MeV u(-1). Typical examples of the deposited energy T (b) and m-fold ionization probabilities Pm( b) used for the cross-section calculations as a function of the impact parameter b are given. Calculated m-fold electron-loss cross sections are in good agreement with available experimental data. Although the projectile charge is rather high, the contribution of multiple-electron-loss

  • 46. Masszi, Ferenc
    et al.
    Stolt, Lars
    Tove, PA
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Tarnay, K
    A comparison between the diffusion model and the combined diffusion-thermionic-emission model for MS junctions by two-carrier numerical computations1981In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 24, p. 456-Article in journal (Refereed)
  • 47.
    Mattera, Andrea
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorelov, D.
    Lantz, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lourdel, B.
    Uppsala University.
    Penttila, H.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ryzhov, I.
    A ROOT-based analysis tool for measurements of neutron-induced fission products at the IGISOL facility2012In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T150, p. 014025-Article in journal (Refereed)
    Abstract [en]

    For the sustainable development of nuclear energy, the handling of used nuclear fuel is a key issue. Innovative fuel cycles are being developed for the transmutation of minor actinides and long-lived fission products. In view of these developments, accurate knowledge of the fuel inventory is necessary. The IGISOL facility with JYFLTRAP, at the accelerator laboratory of the University of Jyvaskyla, will be used to measure independent fission yield distributions from neutron-induced fission on different actinides. In this paper, an analysis tool is developed, using the CERN-based ROOT Data Analysis Framework, with the objective of performing full data analysis within the same code. The analysis tool is currently being tested on the data from measurements with 25 MeV protons on a Th-232 target, and some preliminary results are presented.

  • 48.
    Mattsson, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Astronomy and Space Physics.
    The origin of carbon revisited: winds of carbon-stars2008In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T133, p. 014027-Article in journal (Refereed)
    Abstract [en]

    Chemical evolution models, differing in the nucleosynthesis prescriptions (yields) for carbon, nitrogen and oxygen, have been computed for the Milky Way and Andromeda (NGC 224). All models fit the observed O/H gradients well and reproduce the main characteristics of the gas distributions, but they are also designed to do so. The N/O gradient for NGC 224 cannot be reproduced without ad hoc modifications to the yields and a similar result is obtained for the Milky Way N/O gradient, although in the latter case the slopes of the gradients obtained with unmodified yields are consistent with the observed gradient. For the C/O gradients (obtained from B stars) the results are inconclusive. The C/Fe, N/Fe, O/Fe versus Fe/H, as well as C/O versus O/H trends predicted by the models for the solar neighbourhood were compared with stellar abundances from the literature. For O/Fe versus Fe/H, all models fit the data, but for C/Fe, N/Fe versus Fe/H and C/O versus O/H, only modified sets of yields provide good fits. Since in the best-fit model, the yields were modified such that carbon should be primarily produced in low-mass stars, it is quite possible that in every environment where the peak of star formation happened a few Gyr back in time, the winds of carbon stars are responsible for most of the carbon enrichment, although models with a significant contribution from high-mass stars cannot be ruled out. In the solar neighbourhood, almost two-thirds of the carbon in the interstellar medium may come from carbon stars. Finally, the challenges met by stellar evolution and nucleosynthesis modelling due to this 'carbon star hypothesis' for the origin of carbon are discussed. It is suggested that a mass-loss prescription where the mass-loss rate depends on the carbon excess may act as a self-regulating mechanism for how much carbon a carbon star can deliver to the interstellar medium.

  • 49.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Electrochemical measurements of the electronic density of states2015In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 90, no 9, article id 094005Article in journal (Refereed)
    Abstract [en]

    We present a simple electrochemical method, called intercalation spectroscopy, to study the electronic density-of-states of intercalation materials. It is based on the realization that electrochemical quasi-steady state potential curves of a number of materials exhibit fine structure in good agreement with features in the density of electronic states. Different electrochemical techniques are able to give this information, but chronopotentiometry appears to have advantages from an experimental viewpoint. In this paper we compare the so called 'electrochemical density-of-states' of amorphous and crystalline structures. We also address the limitations of intercalation spectroscopy due to kinetic effects, i.e. very slow relaxations of the charge carriers. Intercalation spectroscopy is in principle very sensitive, although in limited energy ranges, and is able to give information complementary to electron and x-ray spectroscopies for a number of materials.

  • 50.
    NORDBLAD, P
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    LUNDGREN, L
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    BECKMAN, O
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    MAGNETIC CLUSTER EFFECTS IN FESI1-XGEX1983In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 28, p. 246-248Article in journal (Refereed)
12 1 - 50 of 84
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