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| 2. |
- Ghetti, R., et al.
(författare)
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Influence of multiple sources on the two-neutron correlation function in Ni-induced, intermediate energy, heavy ion reactions
- 2001
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Ingår i: Physical Review C. Nuclear Physics. - : American Physical Society. - 0556-2813 .- 1089-490X. ; 64:1
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Tidskriftsartikel (refereegranskat)abstract
- The strength of the neutron-neutron correlation function from the E=45AMeV58Ni+27Al, natNi, and 197Au reactions depends on the neutron parallel velocity. This indicates the presence of multiple sources of neutron emission. We find these sources consistent with a dissipative, binary reaction mechanism as it is described by, e.g., Boltzmann-Uehling-Uhlenbeck calculations.
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| 4. |
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| 5. |
- Lebedev, A.A., et al.
(författare)
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Amplification of the signal in triode structures of ion detectors based on 6H-SIC epitaxial films
- 2001
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 79:26, s. 4447-4449
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Tidskriftsartikel (refereegranskat)abstract
- The possibility of about 50 times the inneramplification of signals in SiC-based detectors of short-range ions is shown. The detector has an n-p-n+-like structure, where the p-type base was grown epitaxially on a 6H n+-SiC substrate. To complete the structure a Schottky barrier was made on top. Detector parameters were investigated in a "floating base" regime. Alpha particles from 244Cm were used and the augmentation of signal (E) with increasing applied voltage (U) was investigated. A superlinear increase of E was observed with a significant (tens of times) amplification of the introduced by the alpha particle nonequilibrium charge. It was also found that the nonuniformity of the diffusion-drift carrier transport parameters in the films does not exceed 10%. © 2001 American Institute of Physics.
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| 6. |
- Urrata, M, et al.
(författare)
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Neutron-neutron Intensity Interferometry in E/A = 45 MeV 58Ni + 27Al, 58Ni and 197Au Reactions
- 2000
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Ingår i: Physical Review C. Nuclear Physics. - : American Institute of Physics (AIP). - 0556-2813 .- 1089-490X. ; 62
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Tidskriftsartikel (refereegranskat)abstract
- Small angle neutron-neutron correlations have been measured for the E/A=45 MeV 58Ni+27Al, natNi, and 197Au reactions. Two-neutron correlation functions, both integrated and gated on the total momentum of the neutron pair, have been constructed. In order to explain these data, a fraction of fast "dynamical" emission is needed in addition to slower evaporative emission. The overall emission time scale is shorter for the symmetric system, indicating that the dynamical component is stronger in this case.
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| 7. |
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| 8. |
- Kalinina, E., et al.
(författare)
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Characterization of Al-implanted 4H SiC high voltage diodes
- 2002
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Ingår i: Physica Scripta. - 0031-8949 .- 1402-4896. ; T101, s. 207-210
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Tidskriftsartikel (refereegranskat)abstract
- The properties of 4H-SiC chemical vapor deposition epitaxial layers were studied by different methods. The effects of structural defects in 4H-SiC epitaxial layers on electrical and luminescence properties of Al high dose ion implanted p(+)-n junctions were studied. It has been shown that the structural imperfections of low-doped layers affect some electrical characteristics of the ion doped p(+)-n junctions created in these epitaxial layers.
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| 9. |
- Severo, J. H. F., et al.
(författare)
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Magnetic islands and plasma rotation in the Tokamak Chauffage Alfven Bresilien tokamak
- 2004
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 11:2, s. 846-848
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Tidskriftsartikel (refereegranskat)abstract
- Collisional plasma rotation in the Tokamak Chauffage Alfven Bresilien (TCABR) tokamak [J. H. F. Severo, I. C. Nascimento, V. S. Tsypin, and R. M. O. Galvao, Nucl. Fusion 43, 1047 (2003)] has been experimentally studied. It was found that the measured plasma poloidal rotation velocity agrees within error limits with neoclassical theoretical predictions, and toroidal velocity with experimental results obtained in analogous tokamaks, almost everywhere along the minor radius r, except for measurements at r/asimilar or equal to0.56 and r/asimilar or equal to0.89 (the minor radius of TCABR tokamak a=18 cm). For the first point, the measured plasma rotation velocities are higher than the velocity of the background plasma, respectively similar to30% and similar to10% for the poloidal and toroidal rotation velocities. Using a set of 22 Mirnov coils displaced poloidally, magnetic field perturbations were measured in shots adjusted to reproduce the ones of the previous plasma rotation measurements, and the results confirm that in the region r/asimilar or equal to0.89 the plasma rotates together with the magnetic island (3,1).
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| 10. |
- Janson, M S, et al.
(författare)
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Channeled implants in 6H silicon carbide
- 2000
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Ingår i: SILICON CARBIDE AND RELATED MATERIALS - 1999 PTS, 1 & 2. ; , s. 889-892
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Konferensbidrag (refereegranskat)abstract
- Implants of MeV B-11, Al-27 and Ga-69 into the <0001> channel of 6H-SiC have been performed and concentration versus depth profiles have been obtained utilizing secondary ion mass spectrometry (SIMS). The experiment shows that the deepest channeled Ga ions reach a depth of 6.6 mum, which is 4 times deeper than the projected range of a random angle implantation, while the deepest channeled B ions only exceed the random projected range by 40%. Measurements at several implantation fluences show that implantation induced damage quench the deep channeling at fluences around 2 and 10x10(13) cm(-2) for Al and Ga, respectively, while only a minor fluence dependence is found in the B implants at fluences up to 2.6x10(14) cm(-2). The ion mass dependence of these effects is explained by the electronic to nuclear stopping ratios. Monte Carlo simulations of the channeling implants have also been performed and good agreements are found between simulations and experimental data.
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| 11. |
- Morvan, E, et al.
(författare)
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Damage reduction in channeled ion implanted 6H-SiC
- 2000
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Ingår i: SILICON CARBIDE AND RELATED MATERIALS - 1999 PTS, 1 & 2. ; , s. 893-896
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Konferensbidrag (refereegranskat)abstract
- We compare damage effects of “random” (off-axis) and [0001] aligned implants of 1.5 MeV Al into 6H-SiC. Both channeled and random equivalent SIMS profiles have been used to adjust model parameters of the simulator. Depth resolved Raman measurements show that at ion doses below similar to 5x10(14) cm(-2), the integral damage is reduced by a factor of similar to2.5 for the channeled implant. This confirms the corresponding reduction of defect concentrations predicted by simulations.
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| 12. |
- Svensson, BG, et al.
(författare)
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Doping of silicon carbide by ion implantation
- 2001
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Ingår i: Materials Science Forum, Vols. 353-356. - : Trans Tech Publications Inc.. - 9780878498734 - 0878498737 ; , s. 549-554, s. 549-554
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Konferensbidrag (refereegranskat)abstract
- A brief survey is given of some recent results on doping of 4H- and 6H-SiC by ion implantation. The doses and energies used are between 10(9) and 10(15) cm(-2) and 100 keV and 5 MeV, respectively, and B and Al ions (p-type dopants) are predominantly studied. After low dose implantation (less than or equal to 10(10) cm(-2)) a strong compensation is observed in n-type samples and this holds irrespective of implantation temperature up to 600 degreesC. However, at higher doses (10(14)-10(15) Al/cm(2)) the rate of defect recombination (annihilation) increases substantially during hot implants (greater than or equal to 200 degreesC) and in these samples one type of structural defect dominates after past-implant annealing at 1700-2000 degreesC. The defect is identified as a dislocation loop composed of clustered interstitial atoms inserted on the basal plane in the hexagonal crystal structure. Finally, transient enhanced diffusion (TED) of ion-implanted boron in 4H-samples is discussed.
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