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- Borge, M. J. G., et al.
(författare)
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Beta-delayed multiparticle emission studies at ISOL-type facilities
- 2004
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 746, s. 243-243
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Konferensbidrag (refereegranskat)abstract
- We report here on the recent beta-decay studies made at ISOL-type Facilities to determine the multiparticle breakup mechanism of excited states in light nuclei by studying them in full kinematics. In particular the results obtained for the A = 9 isobars and the breakup of the 12.7 MeV state in C-12 of unnatural parity are discussed. The breakup of the latter has been debated since more than a decade. Mirror beta transitions in the A = 9 chain are compared and a large asymmetry factor is deduced for the transitions to high excitation energy in Be-9 (11.8 MeV) and B-9 (12.2 MeV) fed in the beta-decay of Li-9 and C-9 respectively. It is shown that the asymmetry is not due to experimental problems or differences in the mechanisms of breakup or in the spin of the states. As no asymmetry is found in the gs to gs transition it must be due to the particular structure of these excited states. The controversy on the breakup mechanism of the 12.7 MeV state is resolved.
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| 6. |
- Rosenblatt, A, et al.
(författare)
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Familial influence on age of onset among siblings with Huntington disease.
- 2001
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Ingår i: American Journal of Medical Genetics. - 0148-7299 .- 1096-8628. ; 105:5, s. 399-403
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Tidskriftsartikel (refereegranskat)abstract
- In order to provide data relevant to a search for modifying genes for age of onset in Huntington disease, we examined the relationship between CAG number and age of onset in a total of 370 individuals from 165 siblingships, in two cohorts of siblings with Huntington disease: an American group of 144 individuals from 64 siblingships, and a Canadian population of 255 individuals from 113 siblingships. Using a logarithmic model to regress the age of onset on the number of CAG triplets, we found that CAG number alone accounted for 65%-71% of the variance in age of onset. The siblingship an individual belonged to accounted for 11%-19% of additional variance. This adds to the previous evidence that there are familial modifiers of the age of onset, independent of the CAG number. Such modifiers may consist of additional genes, which could be the target of a linkage study. A linkage study is feasible with the cooperation of a number of major centers and may be made more efficient by concentrating on sibling pairs that are highly discordant for age of onset.
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| 9. |
- Wang, L. W., et al.
(författare)
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Investigation of damage behaviour and isolation effect of n-type 6H-SiC by implantation of oxygen
- 2000
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Ingår i: Journal of Physics D. - : IOP Publishing. - 0022-3727 .- 1361-6463. ; 33:12, s. 1551-1555
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Tidskriftsartikel (refereegranskat)abstract
- Silicon carbide is an important wide-band-gap semiconductor for high temperature, high-voltage, high-power and high-frequency devices. Electrical isolation is an important aspect for device applications. In this report, oxygen ions, 70 keV with doses ranging from 5 x 10(13) to 5 x 10(15) cm(-2), have been implanted into n-type 6H-SiC to investigate the possibility of forming a high-resistive layer. The damage behaviour and internal stress were checked by Rutherford backscattering spectroscopy and channelling, and an x-ray rocking curve, respectively. Atomic force microscope observations revealed that the surface morphology is quite sensitive to the implantation even at a dose of 1 x 10(14) cm(-2) After annealing in nitrogen at 1200 degrees C, no remarkable damage recovery could be seen if the deposit damage energy is over the critical value. Schottky structures of Au/SiC have been fabricated on the annealed samples and I-V curves of metal/SiC/InGeNi were measured at room temperature at both forward and reverse bias; the electrical isolation effect was observed at proper implantation dosages. The results indicated that there exists a dose window for electrical isolation.
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| 10. |
- Wang, L. W., et al.
(författare)
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Structural and electrical characteristics of oxygen-implanted 6H-SiC
- 2000
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - 0168-583X .- 1872-9584. ; 169, s. 1-5
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Tidskriftsartikel (refereegranskat)abstract
- Silicon carbide is an important wide band gap semiconductor for high-temperature, high-voltage, high-power and high-frequency devices. Ion implantation is an important aspect for both fundamental research and device applications. In this report, oxygen ions, 70 keV with dose ranging from 5 x 10(13) to 5 x 10(15) cm(-2), have been implanted into n-type BH-SIC. The damage behavior and internal stress were checked by Rutherford backscattering spectroscopy and channeling and X-rays rocking curve, respectively. Atomic force microscope observations revealed that the surface morphology is quite sensitive to the implantation even at a dose of 1 x 10(14)/cm(-2). After annealing in nitrogen at 1200 degrees C, no remarkable damage recovery could be seen if the deposit damage energy is above the critical value. Schottky structures of Au/SiC have been fabricated and I-V curves of metal/SiC/InGeNi were measured at room temperature at both forward and reverse bias, electrical isolation effect was observed at proper implantation dose. The results indicated that there exists a dose window for electrical isolations. X-ray photoelectron spectroscopy (XPS) confirmed the formation of silicon oxide and CO due to oxygen implantation. In case of high-dose ion implantation, graphite phase was detected.
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