| 1. |
- Ahuja, R., et al.
(författare)
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Optical properties of 4H-SiC
- 2002
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Ingår i: J. Appl. Phys.. ; 91:4, s. 2099-2103
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Blanco, A, et al.
(författare)
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Progress in timing Resistive Plate Chambers
- 2004
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 535:1-2, s. 272-276
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Tidskriftsartikel (refereegranskat)abstract
- Timing RPCs are Resistive Plate Chambers made with glass and metal electrodes separated by precision spacers. Typical gas gaps are a few hundred micrometers wide. Such counters were introduced in 1999 and have since reached timing accuracies below 50 ps sigma with efficiencies above 99% for MIPs. Applications in high-energy physics have already taken place with several more under study. Some recent developments include the extension of the counting rate capability by over one order of magnitude, to 25 kHz/cm(2), with time resolutions below 100 ps sigma. A prototype RPC-based Positron Emission Tomograph yielded a reconstructed point-source resolution of 0.6 mm FWHM and a modified timing RPC design, featuring 50 mum pitch anode strips, allowed to reach extremely good position resolution for hard X-rays in digital readout mode. An analytically solvable model has allowed us to clarify the basic factors influencing the time resolution.
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| 3. |
- de Oliveira, A. C., et al.
(författare)
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Spectroscopy studies of 4H-SiC
- 2002
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Ingår i: Materials Research. ; 6, s. 43-
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Ferreira, Da Silva A., et al.
(författare)
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Characterization of asymmetric fragmentation patterns in SFM images of porous silicon
- 2000
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Ingår i: Solid State Communications. - 0038-1098 .- 1879-2766. ; 113:12, s. 703-708
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Tidskriftsartikel (refereegranskat)abstract
- Due to possible technological applications in opto-electronic devices, the interest in characterizing porous silicon structure patterns has recently increased. From scanning force microscopy (SFM) we have obtained images of different samples of porous silicon and applied pattern characterization operators on these matrices. In this paper, asymmetric spatial fragmentation in amplitude envelopes of porous silicon samples are characterized by means of a parameter that quantifies the amount of spatial asymmetry in the gradient field. The results show that this method is well suited to characterize silicon porosity quantitatively.
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| 5. |
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| 6. |
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| 7. |
- Moyses, Araujo C., et al.
(författare)
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Band-gap shift of the heavily doped single- and double-donor systems Si : Bi and Si
- 2000
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 62:19, s. 12882-12887
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Tidskriftsartikel (refereegranskat)abstract
- The band-gap shift of the heavily single and double-donor doped systems Si:Bi and Si:P,Bi, prepared by ion implantation, was investigated theoretically and experimentally at room temperature. The calculations were carried out within a framework of the random-phase approximation and the temperature and different many-body effects were taken into account. The experimental data were obtained with photoconductivity measurements. Theoretical and experimental results fall closely together in a wide range of donor concentration.
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| 8. |
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| 9. |
- Zastrow, K. D., et al.
(författare)
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Tritium transport experiments on the JET tokamak
- 2004
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Ingår i: Plasma Physics and Controlled Fusion. - 0741-3335 .- 1361-6587. ; 46, s. B255-B265
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Tidskriftsartikel (refereegranskat)abstract
- An overview is given of the experimental method, the analysis technique and the results for trace tritium experiments conducted on the JET tokamak in 2003. Observations associated with events such as sawtooth collapses, neo-classical tearing modes and edge localized modes are described. Tritium transport is seen to approach neo-classical levels in the plasma core at high density and low q(95), and in the transport barrier region of internal transport barrier (ITB) discharges. Tritium transport remains well above neo-classical levels in all other cases. The correlation of the measured tritium diffusion coefficient and convection velocity for normalized minor radii r/a = [0.65, 0.80] with the controllable parameters q95 and plasma density are found to be consistent for all operational regimes (ELMy H-mode discharges with or without ion cyclotron frequency resonance heating, hybrid scenario and ITB discharges). Scaling with local physics parameters is best described by gyro-Bohm scaling with an additional inverse beta dependence.
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