| 1. |
- Audouin, L., et al.
(författare)
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High-precision measurement of isotopic fission yields of 236 U
- 2018
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 193
-
Konferensbidrag (refereegranskat)abstract
- We report on the second SOFIA experiment, dedicated to the fission yields of 236U∗, analog to 235U(n,f). The measurement is based on the inverse kinematics method, using a relativistic, secondary beam of 236U. Both fission fragments are identified in mass and charge in the SOFIA recoil spectrometer. The obtained isotopic yields are compared with existing spectroscopy measurements and the elemental yields are used to discuss the treatment of the even-odd effect with energy in nuclear data libraries.
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| 2. |
- Bijnens, Johan
(författare)
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ChPT loops for the lattice : Pion mass and decay constant, HVP at finite volume and nn̄ -oscillations
- 2018
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 175
-
Tidskriftsartikel (refereegranskat)abstract
- I present higher loop order results for several calculations in Chiral perturbation Theory. 1) Two-loop results at finite volume for hadronic vacuum polarization. 2) A three-loop calculation of the pion mass and decay constant in two-flavour ChPT. For the pion mass all needed auxiliary parameters can be determined from lattice calculations of ππ-scattering. 3) Chiral corrections to neutron-anti-neutron oscillations.
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| 3. |
- Bijnens, Johan
(författare)
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On the Hadronic light-by-light contribution to the muon g-2
- 2018
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 179
-
Tidskriftsartikel (refereegranskat)abstract
- This talk is about the hadronic light-by-light contribution to the muon anomalous magnetic moment, mainly our old work but including some newer results as well. It concentrates on the model calculations. Most attention is paid to pseudo-scalar exchange and the pion loop contribution. Scalar, a1-exchange and other contributions are shortly discussed as well. For the π0-exchange a possible large cancellation between connected and disconnected diagrams is expected.
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| 4. |
- Bouzid, Mehdi, et al.
(författare)
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Non-local rheology of dense granular flows
- 2017
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 140
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Tidskriftsartikel (refereegranskat)abstract
- The rheology of dense granular flows is studied numerically in a shear cell controlled at constant pressure and shear stress, confined between two granular shear flows. We show that a liquid state can be achieved even far below the yield stress, whose flow can be described with the same rheology as above the yield stress. A non-local constitutive relation is derived from dimensional analysis through a gradient expansion and calibrated using the spatial relaxation of velocity profiles observed under homogeneous stresses. Both for frictional and frictionless grains, the relaxation length is found to diverge as the inverse square root of the distance to the yield point, on both sides of that point. We also make use of a micro-rheometer to determine the influence of a distant shear band on the local rheological behaviour. Finally, we compare various approaches based on different non-local constitutive relations and choices for the fluidity parameter. We emphasise that, to discriminate between the different approaches proposed in the literature, one has to go beyond the predictions derived from linearisation around a uniform stress profile, such as that obtained in a simple shear cell. We argue that future tests can be based on the nature of the chosen fluidity parameter, and the related boundary conditions, as well as the hypothesis made to derive the models and the dynamical mechanisms underlying their dynamics.
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| 5. |
- Brydegaard, Mikkel, et al.
(författare)
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Short-Wave infrared atmospheric scheimpflug lidar
- 2018
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. ; 176
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Konferensbidrag (refereegranskat)abstract
- Atmospheric dual-band Scheimpflug lidar is demonstrated at 980 and 1550 nm. Signals are compared during three weather conditions, and the spatio-temporal resolution of the atmospheric structure is considered. The potential for aerosol classification is evaluated, and future directions are discussed.
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| 6. |
- Chatillon, A., et al.
(författare)
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Accurate measurements of fission-fragment yields in U-234,U-235,U-236,U-238(gamma,f) with the SOFIA set-up
- 2016
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. - 9782759819706 ; 111
-
Konferensbidrag (refereegranskat)abstract
- SOFIA (Studies On Fission with Aladin) is a new experimental set-up dedicated to accurate measurement of fission-fragments isotopic yields. It is located at GSI, the only place to use inverse kinematics at relativistic energies in order to study the (gamma,f) electromagnetic-induced fission. The SOFIA set-up is a large-acceptance magnetic spectrometer, which allows to fully identify both fission fragments in coincidence on the whole fission-fragment range. This paper will report on fission yields obtained in U-234,U-235,U-236,U-238(gamma,f) reactions.
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| 7. |
- Deen, Pascale, et al.
(författare)
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A design study of VOR: A versatile optimal resolution chopper spectrometer for the ESS
- 2015
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Ingår i: QENS/WINS 2014 - 11th International Conference on Quasielastic Neutron Scattering and 6th International Workshopon Inelastic Neutron Spectrometers. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 83, s. 03002-03002
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Konferensbidrag (refereegranskat)abstract
- VOR, the versatile optimal resolution chopper spectrometer, is designed to probe dynamic phenomena that are currently inaccessible for inelastic neutron scattering due to flux limitations. VOR is a short instrument by the standards of the European Spallation Source (ESS), 30.2m moderator to sample, and provides instantaneous access to a broad dynamic range, 1-120 meV within each ESS period. The short instrument length combined with the long ESS pulse width enables a quadratic flux increase, even at longer wavelengths, by relaxing energy resolution from Delta E/E = 1% up to Delta E/E = 7%. This is impossible both on a long chopper spectrometer at the ESS and with instruments at short pulsed sources. In comparison to current day chopper spectrometers, VOR can offer an order of magnitude improvement in flux for equivalent energy resolutions, Delta E/E = 1-3%. Further relaxing the energy resolution enables VOR to gain an extra order of magnitude in flux. In addition, VOR has been optimised for repetition rate multiplication (RRM) and is therefore able to measure, in a single ESS period, 6-14 incident wavelengths, across a wavelength band of 9 angstrom with a novel chopper configuration that transmits all incident wavelengths with equivalent counting statistics. The characteristics of VOR make it a unique instrument with capabilities to access small, limited-lifetime samples and transient phenomena with inelastic neutron scattering.
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| 8. |
- Ehlers, G., et al.
(författare)
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Neutron xyz - polarization analysis at a time-of-flight instrument
- 2015
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Ingår i: QENS/WINS 2014 - 11th International Conference on Quasielastic Neutron Scattering and 6th International Workshopon Inelastic Neutron Spectrometers. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 83, s. 03004-03004
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Konferensbidrag (refereegranskat)abstract
- When implementing a dedicated polarization analysis setup at a neutron time-of-flight instrument with a large area detector, one faces enormous challenges. Nevertheless, significant progress has been made towards this goal over the last few years. This paper addresses systematic limitations of the traditional method that is used to make these measurements, and a possible strategy to overcome these limitations. This will be important, for diffraction as well as inelastic experiments, where the scattering occurs mostly out-of-plane.
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| 9. |
- Elter, Zsolt, 1987, et al.
(författare)
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Energy Correlation of Prompt Fission Neutrons
- 2016
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. - 9782759819706 ; 111, s. Art no 05003-
-
Konferensbidrag (refereegranskat)abstract
- In all cases where neutron fluctuations in a branching process (such as in multiplicity measurements) are treated in an energy dependent description, the energy correlations of the branching itself (energy correlations of the fission neutrons) need to be known. To date, these are not known from experiments. Such correlations can be theoretically and numerically derived by modelling the details of the fission process. It was suggested earlier that the fact that the prompt neutrons are emitted from the moving fission targets, will influence their energy and angular distributions in the lab system, which possibly induces correlations. In this paper the influence of the neutron emission process from the moving targets on the energy correlations is investigated analytically and via numerical simulations. It is shown that the correlations are generated by the random energy and direction distributions of the fission fragments. Analytical formulas are derived for the two-point energy distributions, and quantitative results are obtained by Monte-Carlo simulations. The results lend insight into the character of the two-point distributions, and give quantitative estimates of the energy correlations, which are generally small.
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| 10. |
- Fernandez-Garcia, J. P., et al.
(författare)
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Li-11 structural information from inclusive break-up measurements
- 2015
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 88
-
Konferensbidrag (refereegranskat)abstract
- Structure information of Li-11 halo nucleus has been obtained from the inclusive break-up measurements of the Li-11+Pb-208 reactions at energies around the Coulomb barrier (E-lab = 24.3 and 29.8 MeV). The effective break-up energy and the slope of B(E1) distribution close to the threshold have been extracted from the experimental data.
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| 11. |
- Goncalves, V. P.
(författare)
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Searching saturation effects in inclusive and exclusive eA processes
- 2016
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 112
-
Tidskriftsartikel (refereegranskat)abstract
- The searching of saturation effects in inclusive and exclusive eA collisions is reviewed. In particular, we present a comparison between the linear and non-linear predictions for the nuclear structure functions as well as for the Deep Virtual Compton Scattering and vector meson production in future eA colliders.
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| 12. |
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| 13. |
- Grente, L., et al.
(författare)
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The SOFIA experiment: Measurement of 236U fission fragment yields in inverse kinematics
- 2016
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 122:01006
-
Konferensbidrag (refereegranskat)abstract
- The SOFIA (Studies On FIssion with Aladin) experiment aims at measuring fission-fragments isotopic yields with high accuracy using inverse kinematics at relativistic energies. This experimental technique allows to fully identify the fission fragments in nuclear charge and mass number, thus providing very accurate isotopic yields for low energy fission of a large variety of fissioning systems. This report focuses on the latest results obtained with this set-up concerning electromagnetic-induced fission of 236U.
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| 14. |
- Gustafson, Gösta
(författare)
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Effects of diffraction in pp and pA collisions
- 2017
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 141
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Tidskriftsartikel (refereegranskat)abstract
- Diffractive excitation is a large fraction of the pp cross section, also at high energies. Diffraction has been described by multi-Regge diagrams, or in the Good-Walker formalism as a result of fluctuations. The two formalisms are, however, just different sides of the same phenomenon. The dipole cascade formalism in impact parameter space is well suited to describe diffractive excitation including effects of saturation. Diffractive excitation is also an important effect in pA scattering, where the Glauber formalism has been used to estimate the number of NN subcollisions and of "wounded" nucleons. Diffractive excitation has here been either neglected or included in a simplified way, not including excitation of target nucleons. In this talk we discuss how these effects can be included with the help of the dipole cascade model DIPSY.
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| 15. |
- Gustafson, Gösta
(författare)
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Minireview on diffraction
- 2015
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Ingår i: Xliv International Symposium on Multiparticle Dynamics (Ismd 2014). - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 90, s. 06002-06002
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Konferensbidrag (refereegranskat)abstract
- A short review is presented on diffractive excitation in high energy collisions. [GRAPHICS] .
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| 16. |
- Hennig, A., et al.
(författare)
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Mixed-symmetry octupole and hexadecapole excitations in N=52 isotones
- 2015
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. - 9782759817948 ; 93
-
Konferensbidrag (refereegranskat)abstract
- In addition to the well-established quadrupole mixed-symmetry states, octupole and hexadecapole excitations with mixed-symmetry character have been recently proposed for the N = 52 isotones 92Zr and 94Mo. We performed two inelastic proton-scattering experiments to study this kind of excitations in the heaviest stable N = 52 isotone 96Ru. From the combined experimental data of both experiments absolute transition strengths were extracted.
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| 17. |
- Hurley, Ryan C., et al.
(författare)
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Force measurements in stiff, 3D, opaque granular materials
- 2017
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 140
-
Tidskriftsartikel (refereegranskat)abstract
- We present results from two experiments that provide the first quantification of inter-particle force networks in stiff, 3D, opaque granular materials. Force vectors between all grains were determined using a mathematical optimization technique that seeks to satisfy grain equilibrium and strain measurements. Quantities needed in the optimization - the spatial location of the inter-particle contact network and tensor grain strains - were found using 3D X-ray diffraction and X-ray computed tomography. The statistics of the force networks are consistent with those found in past simulations and 2D experiments. In particular, we observe an exponential decay of normal forces above the mean and a partition of forces into strong and weak networks. In the first experiment, involving 77 single-crystal quartz grains, we also report on the temporal correlation of the force network across two sequential load cycles. In the second experiment, involving 1099 single-crystal ruby grains, we characterize force network statistics at low levels of compression.
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| 18. |
- Jurado, B., et al.
(författare)
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Investigation of the surrogate-reaction method via the simultaneous measurement of gamma-emission and fission probabilities
- 2017
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 146
-
Konferensbidrag (refereegranskat)abstract
- We present the results of two experiments where we have measured for the first time simultaneously the fission and gamma-decay probabilities induced by different surrogate reactions. In particular, we have investigated the 238 U(d,p), 238 U( 3 He,t) and 238 U( 3 He, 4 He) reactions as surrogates for the neutron-induced n + 238 U, n + 237 Np and n + 236 U reactions, respectively. In the region where gamma emission, neutron emission and fission compete, our results for the fission probabilities agree fairly well with the neutron-induced data, whereas our gamma-decay probabilities are significantly higher than the neutron-induced data. The interpretation of these results is not obvious and is discussed within the framework of the statistical model with preliminary results for calculated spin-parity distributions populated in surrogate reactions. We also present future plans for surrogate-reaction studies in inverse kinematics with radioactive-ion beams at storage rings.
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| 19. |
- Kern, Ralph, et al.
(författare)
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Search for Isovector Valence-Shell Excitations in 140Nd and 142Sm via Coulomb excitation reactions of radioactive ion beams
- 2018
-
Ingår i: International Conference on Nuclear Structure and Related Topics (NSRT18). - : EDP Sciences. - 2101-6275. ; 194
-
Konferensbidrag (refereegranskat)abstract
- Projectile Coulomb excitation experiments were performed at HIE-ISOLDE at CERN with the radioactive ion beams of 140Nd and 142Sm. Ions with an energy of 4:62 MeV/A were impinging on a 1.45 mg/cm2 thick 208Pb target. The γ-rays depopulating the Coulomb-excited states were recorded by the HPGe-array MINIBALL and scattered particles were detected by a double-sided silicon strip detector. Experimental intensities were used for the determination of electromagnetic transition matrix elements. A preliminary result of the B(M1; 2+ 3 → 2+ 1) of 140Nd and an upper limit for the case of 142Sm are revealing the main fragments of the proton-neutron mixed-symmetry 2+ 1;ms states.
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| 20. |
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| 21. |
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| 22. |
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| 23. |
- Lalovic, Natasa, et al.
(författare)
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Analysis of the Response of AGATA Detectors at GSI
- 2015
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. - 9782759817948 ; 93, s. 07007-07007
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Konferensbidrag (refereegranskat)abstract
- In 2012 and 2014 the γ-ray tracking spectrometer AGATA was operated at the SIS/FRS facility at GSI in Darmstadt, Germany. The performance of the array is discussed, outlining some important aspects of the offline data processing and analysis. Relying on the data obtained from measurements with standard γ-ray sources, a first estimate of the photopeak efficiency and peak-to-total (P/T) is presented.
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| 24. |
- Lebois, M., et al.
(författare)
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Studies for γ-ray emission in the fission process with LICORNE
- 2016
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 122:01010
-
Konferensbidrag (refereegranskat)abstract
- The LICORNE neutron source is a new device at the ALTO facility. Its use of inverse kinematics makes the production of naturally focused neutron beams possible with an energy range of 0.5 to 4 MeV. This is perfect for any studies concerning fast neutron induced reaction based on detection setup that require to be placed in a compact geometry - such as Ge based ? detection setup. In this paper, neutron production with LICORNE is described. The development of a gascell target and the extension of the energy range up to 7 MeV with the p(11B,n)11C are presented. An overview of the major research fields studied with LICORNE is given and two types of experiment are presented. The first one dedicated to prompt fission ?-ray emission in fission, as a function of incident neutron energy, is described. Some preliminary results are shown. The second, in the context of the MINORCA campaign, is detailed. The most recent outcomes in the data analysis process are also presented.
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| 25. |
- Lopez-Martens, A., et al.
(författare)
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Stability and synthesis of superheavy elements: Fighting the battle against fission - example of No-254
- 2016
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. - 9782759890118 ; 131
-
Konferensbidrag (refereegranskat)abstract
- Superheavy nuclei exist solely due to quantum shell effects, which create a pocket in the potential-energy surface of the nucleus, thus providing a barrier against spontaneous fission. Determining the height of the fission barrier and its angular-momentum dependence is important to quantify the role that microscopic shell corrections play in enhancing and extending the limits of nuclear stability. In this talk, the first measurement of a fission barrier in the very heavy nucleus No-254 will be presented.
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| 26. |
- Lubenchenko, Alexander, 1966, et al.
(författare)
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An XPS method for layer profiling of NbN thin films
- 2017
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 132, s. Art no 03053-
-
Konferensbidrag (refereegranskat)abstract
- Layer chemical and phase profiling of niobium nitride thin films on a silicon substrate oxidized on air was performed with the help of a method designed by us. The method includes: a new method of background subtraction of multiple inelastically scattered photoelectrons considering depth inhomogeneity of electron inelastic scattering; a new method of photoelectron line decomposition into component peaks considering physical nature of different decomposition parameters; joint solution of the background subtraction and photoelectron line decomposition problems; control of line decomposition accuracy with the help of a suggested performance criterion; calculation of layer thicknesses for a multilayer target using a simple formula.
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| 27. |
- Malmqvist, Elin, et al.
(författare)
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CW Laser radar for combustion diagnostics
- 2018
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 176
-
Tidskriftsartikel (refereegranskat)abstract
- A CW-laser radar system developed for combustion diagnostics is described. The system is based on triangulation to attain range information. A portable system has been constructed and here we show some result from measurements in various flames, for example Rayleigh scattering thermometry and monitoring of particle distributions with high temporal and spatial resolution. The concept can equally well be based on pulsed lasers, allowing suppression of background emission through gated detection.
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| 28. |
- Martins, Murillo L., et al.
(författare)
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Encapsulation of paclitaxel into a bio-nanocomposite. A study combining inelastic neutron scattering to thermal analysis and infrared spectroscopy
- 2015
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 83
-
Konferensbidrag (refereegranskat)abstract
- The anticancer drug paclitaxel was encapsulated into a bio-nanocomposite formed by magnetic nanoparticles, chitosan and apatite. The aim of this drug carrier is to provide a new perspective against breast cancer. The dynamics of the pure and encapsulated drug were investigated in order to verify possible molecular changes caused by the encapsulation, as well as to follow which interactions may occur between paclitaxel and the composite. Fourier transformed infrared spectroscopy, thermal analysis, inelastic and quasi-elastic neutron scattering experiments were performed. These very preliminary results suggest the successful encapsulation of the drug.
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| 29. |
- Merdasa, Aboma, et al.
(författare)
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Non-radiative processes in metal halide perovskite semiconductors probed by photoluminescence microscopy
- 2018
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Ingår i: XIII International Conference on Hole Burning, Single Molecule, and Related Spectroscopies: Science and Applications (HBSM-2018). - : EDP Sciences. - 2101-6275. ; 190
-
Konferensbidrag (refereegranskat)abstract
- Organo metal halide perovskites are solution processed semiconductors that recently attracted a great attention. They possess a rather "soft" and (photo) chemically active solid structure allowing for ion migration and other mass diffusion processes. This is a likely reason why non-radiative recombination centres in these materials are activated and deactivated on relatively slow time-scales. This dynamics reveals as photoluminescence (PL) fluctuations (blinking) of individual microcrystals and local areas of films and allows for application of a broad range of single molecule spectroscopy methods including optical super-resolution. Studying PL blinking resolves properties of individual non-radiative centres and helps to unravel their chemical nature.
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| 30. |
- Parra-Santos, Teresa, et al.
(författare)
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Numerical modelling of swirling diffusive flames
- 2016
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 114
-
Tidskriftsartikel (refereegranskat)abstract
- Computational Fluid Dynamics has been used to study the mixing and combustion of two confined jets whose setup and operating conditions are those of the benchmark of Roback and Johnson. Numerical model solves 3D transient Navier Stokes for turbulent and reactive flows. Averaged velocity profiles using RNG swirl dominated k-epsilon model have been validated with experimental measurements from other sources for the non reactive case. The combustion model is Probability Density Function. Bearing in mind the annular jet has swirl number over 0.5, a vortex breakdown appears in the axis of the burner. Besides, the sudden expansion with a ratio of 2 in diameter between nozzle exits and the test chamber produces the boundary layer separation with the corresponding torus shape recirculation. Contrasting the mixing and combustion models, the last one produces the reduction of the vortex breakdown.
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| 31. |
- Parra, Teresa, et al.
(författare)
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Numerical modelling of flow pattern for high swirling flows
- 2015
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Ingår i: Efm14 - Experimental Fluid Mechanics 2014. - : EDP Sciences. - 2100-014X .- 2101-6275. ; 92, s. 02059-02059
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Konferensbidrag (refereegranskat)abstract
- This work focuses on the interaction of two coaxial swirling jets. High swirl burners are suitable for lean flames and produce low emissions. Computational Fluid Dynamics has been used to study the isothermal behaviour of two confined jets whose setup and operating conditions are those of the benchmark of Roback and Johnson. Numerical model is a Total Variation Diminishing and PISO is used to pressure velocity coupling. Transient analysis let identify the non-axisymmetric region of reverse flow. The center of instantaneous azimuthal velocities is not located in the axis of the chamber. The temporal sampling evidences this center spins around the axis of the device forming the precessing vortex core (PVC) whose Strouhal numbers are more than two for Swirl numbers of one. Influence of swirl number evidences strong swirl numbers are precursor of large vortex breakdown. Influence of conical diffusers evidence the reduction of secondary flows associated to boundary layer separation.
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| 32. |
- Puech, J., et al.
(författare)
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CNES-Chalmers-IAP-ONERA-XLIM activities in the domain of high RF power breakdown phenomena
- 2017
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 157
-
Konferensbidrag (refereegranskat)abstract
- Multipactor breakdown is an important potential failure mechanism in many different microwave devices working under close to vacuum conditions. Applications range from space borne RF equipment to high-power microwave generators. The basic physics involved in the multipactor phenomenon is well known for the case of two infinite pallel plates made of metal. However, most realistic RF device geometries involve inhomogeneous RF electric fields and curved field lines and sometimes also dielectric material. The purpose of this paper is to set up methodologies to determine the Multipactor threshold in such situations.
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| 33. |
- Ramos, D., et al.
(författare)
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Dependence of Fission-Fragment Properties On Excitation Energy For Neutron-Rich Actinides
- 2016
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. - 9782759819706 ; 111
-
Konferensbidrag (refereegranskat)abstract
- Experimental access to full isotopic fragment distributions is very important to determine the features of the fission process. However, the isotopic identification of fission fragments has been, in the past, partial and scarce. A solution based on the use of inverse kinematics to study transfer-induced fission of exotic actinides was carried out at GANIL, resulting in the first experiment accessing the full identification of a collection of fissioning systems and their corresponding fission fragment distribution. In these experiments, a U-238 beam at 6.14 AMeV impinged on a carbon target to produce fissioning systems from U to Am by transfer reactions, and Cf by fusion reactions. Isotopic fission yields of Cf-250, Cm-244, Pu-240, Np-239 and U-238 are presented in this work. With this information, the average number of neutrons as a function of the atomic number of the fragments is calculated, which reflects the impact of nuclear structure around Z=50, N=80 on the production of fission fragments. The characteristics of the Super Long, Standard I, Standard II, and Standard III fission channels were extracted from fits of the fragment yields for different ranges of excitation energy. The position and contribution of the fission channels as function of excitation energy are presented.
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| 34. |
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| 35. |
- Rodriguez-Sanchez, J. L., et al.
(författare)
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Dissipative effects in fission investigated in complete kinematics measurements
- 2017
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. - 9782759890200 ; 146
-
Konferensbidrag (refereegranskat)abstract
- The study of dissipative effects in fission has been carried out with fusion-fission reactions by using a limited number of observables, such as the fission probabilities, the mass distribution of the fission fragments, or the neutron multiplicities. However, the large angular momenta gained by the compound nucleus in this kind of reaction could affect the conclusions drawn from such experiments. In this work, we propose to investigate the fission dynamics by the use of spallation reactions on 208Pb because the fissioning systems are produced with low angular momentum, small deformations, and high excitation energies, enhancing the dissipative effects. The complete kinematics measurements of the fission fragments and light-charged particles were performed by the use of the SOFIA setup combined with the inverse kinematics technique, allowing us for the first time a full indentification in atomic and mass number of the two fission fragments. These measurements permit us to define new fission observables for the investigation of the temperature and deformation dependencies of the dissipation parameter.
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| 36. |
- Rodriguez-Sanchez, J. L., et al.
(författare)
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Dissipative effects in fission investigated with proton-on-lead reactions
- 2016
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. - 9788874381012 ; 117, s. Art. no. 08017-
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Konferensbidrag (refereegranskat)abstract
- The complete kinematic measurement of the two fission fragments permitted us to investigate dissipative effects at large deformations, between the saddle-point and the corresponding scission configurations. Up to now, this kind of study has only been performed with fusionfission reactions using a limited number of observables, such as the mass distribution of the fission fragments or the neutron multiplicities. However, the large angular momenta gained by the compound nucleus could affect the conclusions drawn from such experiments. In this work, the use of spallation reactions, where the fissioning systems are produced with low angular momentum, small deformations and high excitation energies, favors the study of dissipation, and allowed us to define new observables, such as postscission neutron multiplicities and the neutron excess of the final fission fragments as a function of the atomic number of the fissioning system. These new observables are used to investigate the dissipation at large deformations.
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| 37. |
- Scheck, M., et al.
(författare)
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Do nuclei go pear-shaped? Coulomb excitation of Rn-220 and Ra-224 at REX-ISOLDE (CERN)
- 2015
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Ingår i: Cgs15 - Capture Gamma-ray Spectroscopy and Related Topics. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 93, s. 01038-01038
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Konferensbidrag (refereegranskat)abstract
- The IS475 collaboration conducted Coulomb-excitation experiments with post-accelerated radioactive Rn-220 and Ra-224 beams at the REX-ISOLDE facility. The beam particles (E-beam: 2.83 MeV/u) were Coulomb excited using Ni-60, Cd-14, and Sn-120 scattering targets. De-excitation gamma-rays were detected employing the Miniball array and scattered particles were detected in a silicon detector. Exploiting the Coulomb-excitation code GOSIA for each nucleus several matrix elements could be obtained from the measured gamma-ray yields. The extracted < 3 parallel to E3 parallel to 0(+)> matrix element allows for the conclusion that, while Rn-220 represents an octupole vibrational system, Ra-224 has already substantial octupole correlations in its ground state. This finding has i(m)plications for the search of CP-violating Schiff moments in the atomic systems of the adjacent odd-mass nuclei.
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| 38. |
- Scordo, A., et al.
(författare)
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The kaonic atoms research program at DAΦNE : From SIDDHARTA to SIDDHARTA-2
- 2018
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 181
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Tidskriftsartikel (refereegranskat)abstract
- The interaction of antikaons with nucleons and nuclei in the low-energy regime represents an active research field in hadron physics with still many important open questions. The investigation of light kaonic atoms, in which one electron is replaced by a negatively charged kaon, is a unique tool to provide precise information on this interaction; the energy shift and the broadening of the low-lying states of such atoms, induced by the kaon-nucleus hadronic interaction, can be determined with high precision from the atomic X-ray spectroscopy, and this experimental method provides unique information to understand the low energy kaon-nucleus interaction at the production threshold. The lightest atomic systems, like the kaonic hydrogen and the kaonic deuterium deliver, in a model-independent way, the isospin-dependent kaon-nucleon scattering lengths. The most precise kaonic hydrogen measurement to-date, together with an exploratory measurement of kaonic deuterium, were carried out in 2009 by the SIDDHARTA collaboration at the DAΦNE electron-positron collider of LNF-INFN, combining the excellent quality kaon beam delivered by the collider with new experimental techniques, as fast and very precise X-ray detectors, like the Silicon Drift Detectors. The SIDDHARTA results triggered new theoretical work, which achieved major progress in the understanding of the low-energy strong interaction with strangeness reflected by the antikaon-nucleon scattering lengths calculated with the antikaon-proton amplitudes constrained by the SIDDHARTA data. The most important open question is the experimental determination of the hadronic energy shift and width of kaonic deuterium; presently, a major upgrade of the setup, SIDDHARTA-2, is being realized to reach this goal. In this paper, the results obtained in 2009 and the proposed SIDDHARTA-2 upgrades are presented.
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| 39. |
- Severyukhin, A. P., et al.
(författare)
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Two-phonon structures for beta-decay theory
- 2018
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Ingår i: International Conference on Nuclear Structure and Related Topics (NSRT18). - : EDP Sciences. - 2101-6275. ; 194
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Konferensbidrag (refereegranskat)abstract
- The β-decay rates of 60Ca have been studied within a microscopic model, which is based on the Skyrme interaction T45 to construct single-particle and phonon spaces. We observe a redistribution of the Gamow-Teller strength due to the phonon-phonon coupling, considered in the model. For 60Sc, the spin-parity of the ground state is found to be 1+. We predict that the half-life of 60Ca is 0.3 ms, while the total probability of the βxn emission is 6:1%. Additionally, the random matrix theory has been applied to analyze the statistical properties of the 1+ spectrum populated in the β-decay to elucidate the obtained results.
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| 40. |
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| 41. |
- Sogaard, Carsten, et al.
(författare)
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Method for High Accuracy Multiplicity Correlation Measurements
- 2015
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Ingår i: Xliv International Symposium on Multiparticle Dynamics (Ismd 2014). - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 90
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Konferensbidrag (refereegranskat)abstract
- A novel method for measuring particle multiplicity correlations is presented. The method takes reduced acceptance and detection efficiency into account, in a purely statistical manner. The method does therefore not require any information from simulations - only knowledge of the detectors capability. The method provides the ability to measure forward-backward particle multiplicity correlations with high accuracy and negligible bias. The validity of the method is provided through numerous simulations. The correlation values calculated from carefully selected detection acceptances and efficiencies are compared to the con-elation values at the event-generator level. Further validity to the method is given by incorporating different event generators into the simulations. Although the emphasis is on fwd-bwd correlations, the method can be extended to other multiplicity correlation measurements.
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| 42. |
- Tatsuno, H., et al.
(författare)
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Future projects of light kaonic atom X-ray spectroscopy
- 2016
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 130
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Tidskriftsartikel (refereegranskat)abstract
- X-ray spectroscopy of light kaonic atoms is a unique tool to provide precise information on the fundamental KN interaction at the low-energy limit and the in-medium nuclear interaction of K-. The future experiments of kaonic deuterium strong-interaction shift and width (SIDDHARTA-2 and J-PARC E57) can extract the isospin dependent K-N interaction at threshold. The high-resolution X-ray spectroscopy of kaonic helium with microcalorimeters (J-PARC E62) has the possibility to solve the long-standing potential-strength problem of the attractive K--nucleus interaction. Here, the recent experimental results and the future projects of X-ray spectroscopy of light kaonic atoms are presented.
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| 43. |
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| 44. |
- Thomas, Richard D., et al.
(författare)
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DESIREE : Physics with cold stored ion beams
- 2015
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Ingår i: DR2013. - : EDP Sciences. ; 84, s. 01004-01004
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Konferensbidrag (refereegranskat)abstract
- Here we will briefly describe the commissioning of the Double ElectroStatic Ion Ring ExpEriment (DESIREE) facility at Stockholm University, Sweden. This device uses purely electrostatic focussing and deflection elements and allows ion beams of opposite charge to be confined under extreme high vacuum and cryogenic conditions in separate rings and then merged over a common straight section. This apparatus allows for studies of interactions between cations and anions at very low and well-defined centre-of-mass energies (down to a few meV) and at very low internal temperatures (down to a few K).
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| 45. |
- Thuiner, P., et al.
(författare)
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Multi-GEM detectors in high particle fluxes
- 2018
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 174
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Tidskriftsartikel (refereegranskat)abstract
- Gaseous Electron Multipliers (GEM) are well known for stable operation at high particle fluxes. We present a study of the intrinsic limits of GEM detectors when exposed to veiy high particle fluxes of the order of MHz/mm2. We give an interpretation to the variations of the effective gain, which, as a function of the particle flux, first increases and then decreases. Wre also discuss the reduction of the ion back-flow with increasing flux. We present measurements and simulations of a triple GEM detector, describing its behaviour in terms of accumulation of positive ions that results in changes of the transfer fields and the amplification fields. The behaviour is expected to be common to all multi-stage amplification devices where the efficiency of transferring the electrons from one stage to the next one is not 100%.
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| 46. |
- Tsapatsaris, Nikolaos, et al.
(författare)
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From BASIS to MIRACLES: Benchmarking and perspectives for high-resolution neutron spectroscopy at the ESS
- 2015
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Ingår i: QENS/WINS 2014 - 11th International Conference on Quasielastic Neutron Scattering and 6th International Workshopon Inelastic Neutron Spectrometers. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 83, s. 03015-03015
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Konferensbidrag (refereegranskat)abstract
- Results based on virtual instrument models for the first high-flux, high-resolution, spallation based, backscattering spectrometer, BASIS are presented in this paper. These were verified using the Monte Carlo instrument simulation packages McStas and VITESS. Excellent agreement of the neutron count rate at the sample position between the virtual instrument simulation and experiments was found, in both time and energy distributions. This achievement was only possible after a new component for a bent single crystal analyser in McStas, using a Gaussian approximation, was developed. These findings are pivotal to the conceptual design of the next generation backscattering spectrometer, MIRACLES at the European Spallation Source.
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| 47. |
- Zhao, Guangyu, et al.
(författare)
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Inelastic hyperspectral lidar for aquatic ecosystems monitoring and landscape plant scanning test
- 2018
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 176
-
Tidskriftsartikel (refereegranskat)abstract
- We have developed an aquatic inelastic hyperspectral lidar with unrestricted focal-depth and enough sensitivity and spatio-temporal resolution to detect and resolve position and behavior of individual sub-millimeter aquatic organisms. We demonstrate ranging with monitoring of elastic echoes, water Raman signals and fluorescence from chlorophyllbearing phytoplankton and dye tagged organisms. The system is based on a blue CW diode laser and a Scheimpflug optical arrangement.
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| 48. |
- Zhao, Guangyu, et al.
(författare)
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Mobile lidar system for environmental monitoring
- 2018
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 176
-
Tidskriftsartikel (refereegranskat)abstract
- A versatile mobile remote sensing system for multidisciplinary environmental monitoring tasks on the Chinese scene is described. The system includes a 20 Hz Nd:YAG laser-pumped dye laser, optical transmitting/receiving systems with a 30 cm and a 40 cm Newtonian telescope, and electronics, all integrated in a laboratory, installed on a Jiefang truck. Results from field experiments on atomic mercury DIAL mapping and remote laser-induced fluorescence and break-down spectroscopy are given.
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| 49. |
- Zhu, Shiming, et al.
(författare)
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Insect remote sensing using a polarization sensitive cw lidar system in Chinese rice fields
- 2018
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 176
-
Tidskriftsartikel (refereegranskat)abstract
- A joint Chinese-Swedish field campaign of Scheimpflug continuous-wave lidar monitoring of rice-field flying pest insects was pursued in very hot July weather conditions close to Guangzhou, China. The occurrence of insects, birds and bats with almost 200 hours of round-the-clock polarization-sensitive recordings was studied. Wing-beat frequency recordings and depolarization properties were used for target classification. Influence of weather conditions on the flying fauna was also investigated.
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| 50. |
- Bierlich, Christian
(författare)
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Rope Hadronization and Strange Particle Production
- 2018
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Ingår i: 17th International Conference on Strangeness in Quark Matter, SQM 2017. - : EDP Sciences. - 9782759890330 ; 171
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Konferensbidrag (refereegranskat)abstract
- Rope Hadronization is a model extending the Lund string hadronization model to describe environments with many overlapping strings, such as high multiplicity pp collisions or AA collisions. Including effects of Rope Hadronization drastically improves description of strange/non-strange hadron ratios as function of event multiplicity in all systems from e+e- to AA. Implementation of Rope Hadronization in the MC event generators Dipsy and Pythia8 is discussed, as well as future prospects for jet studies and studies of small systems.
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