| 81. |
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| 82. |
- Ulander, Lars, 1962, et al.
(författare)
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VHF/UHF bistatic and passive SAR ground imaging
- 2015
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Ingår i: IEEE National Radar Conference - Proceedings. - 1097-5659. - 9781479982325 ; 2015-June:June, s. 669-673
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Konferensbidrag (refereegranskat)abstract
- Bistatic and passive radar are emerging technologies for covert ground surveillance based on cooperative or non-cooperative transmitters, respectively. The latter uses transmitters of opportunity, e.g. terrestrial digital video broadcasting (DVB-T). In the paper, we show results from two unique experiments conducted using airborne systems operating in the VHF and UHF bands. The first experiment investigates UHF-band passive synthetic aperture radar (SAR) in receive-only mode. DVB-T signals transmitted from a 300-m tall mast are used and SAR images are formed at ranges up to 15 km. The second experiment investigates VHF-band bistatic SAR with a transmitting airborne radar and a receive-only system on a small helicopter. Results show significantly higher signal-to-clutter ratio for man-made objects in forested areas at bistatic elevation angles of 20°. © 2015 IEEE.
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| 83. |
- Valiente-Dobon, JJ, et al.
(författare)
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Evidence for nontermination of rotational bands in Kr-74
- 2005
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Ingår i: Physical Review Letters. - 1079-7114. ; 95:23
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Tidskriftsartikel (refereegranskat)abstract
- Three rotational bands in Kr-74 were studied up to (in one case one transition short of) the maximum spin I-max of their respective single-particle configurations. Their lifetimes have been determined using the Doppler-shift attenuation method. The deduced transition quadrupole moments reveal a modest decrease, but far from a complete loss of collectivity at the maximum spin I-max. This feature, together with the results of mean field calculations, indicates that the observed bands do not terminate at I=I-max.
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| 84. |
- Wadsworth, R., et al.
(författare)
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Evidence for shape coexistence at medium spin in Rb-76
- 2011
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 701:3, s. 306-312
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Tidskriftsartikel (refereegranskat)abstract
- Four previously known rotational bands in Rb-76 have been extended to moderate spins using the Gammasphere and Microball gamma ray and charged particle detector arrays and the Ca-40(Ca-40,3pn) reaction at a beam energy of 165 MeV. The properties of two of the negative-parity bands can only readily be interpreted in terms of the highly successful Cranked Nilsson-Strutinsky model calculations if they have the same configuration in terms of the number of g(9/2) particles, but they result from different nuclear shapes (one near-oblate and the other near-prolate). These data appear to constitute a unique example of shape coexisting structures at medium spins. (C) 2011 Elsevier B.V. All rights reserved.
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| 85. |
- Wadsworth, R., et al.
(författare)
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Terminating states in the positive-parity structures of As 67
- 2018
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Ingår i: Physical Review C. - 2469-9985. ; 98:2
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Tidskriftsartikel (refereegranskat)abstract
- The energy levels and γ-ray decay scheme of the positive-parity states in the Tz=12 nucleus As67 have been studied by using the Ca40(Ar36,2αp)As67 reaction at a beam energy of 145 MeV. Two new band structures have been identified which can be connected to the previously known levels. The results for these bands are compared with configuration-dependent cranked Nilsson-Strutinsky calculations. The good level of agreement between theory and experiment suggests that these structures can be interpreted in terms of configurations that involve three g92 particles and that both possess noncollective terminating states.
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| 86. |
- Wiedeking, M., et al.
(författare)
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Transition strengths and band terminations in 86Zr
- 2003
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 67, s. 1-034320
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Tidskriftsartikel (refereegranskat)abstract
- High angular momentum states in 86Zr were populated through the 58Ni(32S,4p) reaction at 135 MeV using the 88-In. Cyclotron at Lawrence Berkeley National Laboratory. Recoiling 86Zr nuclei were stopped in a thick Ta backing. Prompt multi-γ coincidences with evaporated charged particles were detected using the full array of GAMMASPHERE and the MICROBALL. Mean lifetimes of 36 levels in 86Zr were measured using the Doppler-shift attenuation method. Transition quadrupole moments Qt were found in the range of about 0.3-1.5 e b in the positive-parity bands. The negative-parity bands show Qt values from about 0.25 to 1.2 e b. In the yrast positive-parity band, a sharp drop in collectivity approaching the 30+ state supports the interpretation of band termination in this configuration. Decreasing Qt values approaching the 24+ and 27- states also provide an indication of terminating structures.
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