Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "L4X0:0031 8949 "

Sökning: L4X0:0031 8949

  • Resultat 1-10 av 14
Sortera/gruppera träfflistan
  • Beyer, Franziska, et al. (författare)
  • Defects in low-energy electron-irradiated n-type 4H-SiC
  • 2010
  • Ingår i: Physica Scripta, vol. T141. - IOP Publishing. ; s. 014006
  • Konferensbidrag (refereegranskat)abstract
    • The bistable M-center, previously observed in high-energy proton-implanted 4H-SiC, was detected in low-energy electron-irradiated 4H-SiC using deep-level transient spectroscopy (DLTS). Irradiation increased the DLTS signals of the intrinsic defects Z(1/2) and EH6/7 and introduced the frequently observed defects EH1 and EH3. After the M-center is annealed out at about 650K without bias and at about 575K with bias applied to the sample during the annealing process, a new bistable defect in the low temperature range of the DLTS spectrum, the EB-center, evolves. Since low-energy irradiation affects mainly the carbon atoms in SiC, the M-center and the newly discovered EB-center are most probably carbon-related intrinsic defects.
  • Carlsson, Patrick, 1975-, et al. (författare)
  • The EI4 EPR centre in 6H SiC
  • 2010
  • Ingår i: Physica Scripta, Vol. T141. - IOP Publishing. ; s. 014013
  • Konferensbidrag (refereegranskat)abstract
    • We present the results of our recent electron paramagnetic resonance (EPR) studies of the EI4 EPR centre in electron-irradiated high-purity semi-insulating 6H SiC. Higher signal intensities and better resolution compared with previous studies have enabled a more detailed study of the hyperfine (hf) structure. Based on the observed hf structure due to the interaction with Si and C neighbours, the effective spin S = 1, the C-1h-symmetry and the annealing behaviour, we suggest a carbon vacancy-carbon antisite complex in the neutral charge state, VCVCCSi0, with the vacancies and the antisite in the basal plane, as a new defect model for the centre.
  • Son, Nguyen Tien, et al. (författare)
  • Radiation-induced defects in GaN
  • 2010
  • Ingår i: Physica Scripta, Vol. T141. - IOP Publishing. ; s. 014015
  • Konferensbidrag (refereegranskat)abstract
    • Radiation-induced defects in n-type GaN irradiated by 2 MeV electrons at room temperature were studied by electron paramagnetic resonance (EPR). Four EPR spectra, labelled D1-D4, were observed in irradiated n-type GaN. The D1 spectrum is a broad line (similar to 10-12 mT in line width) with an isotropic g-value g similar to 2.03 and can be detected in all the studied samples in the temperature range of 4-300 K. The D2 centre has an electron spin S = 1/2 and shows a clear hyperfine structure due to interaction with three equivalent N-14. The g-values of the axial configuration are determined to be g(parallel to) = 2.001 and g(perpendicular to) = 1.999. On the basis of the observed hyperfine structure, formation conditions and annealing behaviour, the D2 defect was assigned to the gallium vacancy-oxygen pair in the negative charge state, (VGaON)(-).
  • Widdowson, A., et al. (författare)
  • Experience of handling beryllium, tritium and activated components from JET ITER like wall
  • 2016
  • Ingår i: Physica Scripta. - Institute of Physics Publishing (IOPP).
  • Konferensbidrag (refereegranskat)abstract
    • JET components are removed periodically for surface analysis to assess material migration and fuel retention. This paper describes issues related to handling JET components and procedures for preparing samples for analysis; in particular a newly developed procedure for cutting beryllium tiles is presented. Consideration is also given to the hazards likely due to increased tritium inventory and material activation from 14 MeV neutrons following the planned TT and DT operations (DTE2) in 2017. Conclusions are drawn as to the feasibility of handling components from JET post DTE2.
  • Tholén, Erik, 1979-, et al. (författare)
  • Parametric amplification with weak-link nonlinearity in superconducting microresonators
  • 2009
  • Ingår i: Nobel Symposium 141: Qubits for Future Quantum Information; Gothenburg; 25 May 2009 through 28 May 2009.
  • Konferensbidrag (refereegranskat)abstract
    • Nonlinear kinetic inductance in a high Q superconducting coplanarwaveguide microresonator can cause a bifurcation of the resonance curve. Near thecritical pumping power and frequency for bifurcation, large parametric gain is observedfor signals in the frequency band near resonance. We show experimental results onsignal and intermodulation gain which are well described by a theory of the parametricamplification based on a Kerr nonlinearity. Phase dependent gain, or signal squeezing,is verified with a homodyne detection scheme.
  • Neutrino Physics : Proceedings of Nobel Symposium 129
  • 2006
  • Proceedings (redaktörskap) (övrigt vetenskapligt)abstract
    • PREFACENobel Symposium 129 on Neutrino Physics was held at Haga Slott in Enköping, Sweden during August 19–24, 2004. Invited to the symposium were around 40 globally leading researchers in the field of neutrino physics, both experimental and theoretical. In addition to these participants, some 30 local researchers and graduate students participated in the symposium.The dominant theme of the lectures was neutrino oscillations, which after several years were recently verified by results from the Super-Kamiokande detector in Kamioka, Japan and the SNO detector in Sudbury, Canada. Discussion focused especially on effects of neutrino oscillations derived from the presence of matter and the fact that three different neutrinos exist. Since neutrino oscillations imply that neutrinos have mass, this is the first experimental observation that fundamentally deviates from the standard model of particle physics. This is a challenge to both theoretical and experimental physics. The various oscillation parameters will be determined with increased precision in new, specially designed experiments. Theoretical physics is working intensively to insert the knowledge that neutrinos have mass into the theoretical models that describe particle physics. It will probably turn out that the discovery of neutrino oscillations signifies a breakthrough in the description of the very smallest constituents of matter. The lectures provided a very good description of the intensive situation in the field right now. The topics discussed also included mass models for neutrinos, neutrinos in extra dimensions as well as the `seesaw mechanism', which provides a good description of why neutrino masses are so small.Also discussed, besides neutrino oscillations, was the new field of neutrino astronomy. Among the questions that neutrino astronomy hopes to answer are what the dark matter in the Universe consists of and where cosmic radiation at extremely high energies comes from. For this purpose, large neutrino telescopes are built deep in the Antarctic ice, in the Baikal Lake, and in the Mediterranean Sea.Among prominent unanswered questions, highlighted as one of the most important, was whether neutrinos are Dirac or Majorana particles. By studying neutrino double beta decay, researchers hope to answer this question, but it will put very large demands on detectors.The programme also included ample time for lively and valuable discussions, which cannot normally be held at ordinary conferences.The symposium concluded with a round-table discussion, where participants discussed the future of neutrino physics.Without a doubt, neutrino physics today is moving toward a very exciting and interesting period.An important contribution to the success of the symposium was the wonderful setting that the Haga Slott manor house hotel and conference center offered to the participants.
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 14
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy