skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: High-spin octupole yrast levels in {sup 216}Rn{sub 86}

Abstract

The yrast level structure of {sup 216}Rn has been studied using in-beam spectroscopy {alpha}-{gamma}-{gamma} coincidence techniques through the {sup 208}Pb({sup 18}O, 2{alpha}2n) reaction in the 91-93 MeV energy range, using the 8{pi} GASP-ISIS spectrometer at Legnaro. The level scheme of {sup 216}Rn resulting from this study shows alternating parity bands only above a certain excitation energy. From this result, the lightest nucleus showing evidence of octupole collectivity at low spins is still {sup 216}Fr, thereby defining the lowest-mass corner for this kind of phenomenon as N{>=}129 and Z{>=}87.

Authors:
 [1];  [2]; ;  [3]; ;  [1];  [2];  [2];  [1];  [2]; ; ; ;  [4]; ; ; ; ;  [5];  [6]
  1. Departamento de Fisica, Comision Nacional de Energia Atomica, 1429 Buenos Aires (Argentina)
  2. (Argentina)
  3. CONICET, 1033 Buenos Aires (Argentina)
  4. INFN, Laboratori Nazionali di Legnaro, Legnaro (Italy)
  5. Dipartimento di Fisica, Sezione di Padova, Padova (Italy)
  6. Departamento de Fisica Nuclear, Universidade de Sao Paulo (Brazil)
Publication Date:
OSTI Identifier:
20771265
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 73; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevC.73.024314; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; EXCITATION; FRANCIUM 216; IN-BEAM SPECTROSCOPY; LEAD 208 TARGET; MEV RANGE; NUCLEAR STRUCTURE; OCTUPOLES; OXYGEN 18 REACTIONS; PARITY; RADON 216; SPIN; YRAST STATES

Citation Formats

Debray, M.E., Escuela de Ciencia y Tecnologia, Universidad de San Martin, Davidson, J., Davidson, M., Kreiner, A. J., Cardona, M. A., Escuela de Ciencia y Tecnologia, Universidad de San Martin, CONICET, 1033 Buenos Aires, Hojman, D., CONICET, 1033 Buenos Aires, Napoli, D.R., De Angelis, G., De Poli, M., Gadea, A., Lenzi, S., Bazzacco, D., Lunardi, S., Rossi-Alvarez, C., Ur, C.A., and Medina, N. High-spin octupole yrast levels in {sup 216}Rn{sub 86}. United States: N. p., 2006. Web. doi:10.1103/PhysRevC.73.024314.
Debray, M.E., Escuela de Ciencia y Tecnologia, Universidad de San Martin, Davidson, J., Davidson, M., Kreiner, A. J., Cardona, M. A., Escuela de Ciencia y Tecnologia, Universidad de San Martin, CONICET, 1033 Buenos Aires, Hojman, D., CONICET, 1033 Buenos Aires, Napoli, D.R., De Angelis, G., De Poli, M., Gadea, A., Lenzi, S., Bazzacco, D., Lunardi, S., Rossi-Alvarez, C., Ur, C.A., & Medina, N. High-spin octupole yrast levels in {sup 216}Rn{sub 86}. United States. doi:10.1103/PhysRevC.73.024314.
Debray, M.E., Escuela de Ciencia y Tecnologia, Universidad de San Martin, Davidson, J., Davidson, M., Kreiner, A. J., Cardona, M. A., Escuela de Ciencia y Tecnologia, Universidad de San Martin, CONICET, 1033 Buenos Aires, Hojman, D., CONICET, 1033 Buenos Aires, Napoli, D.R., De Angelis, G., De Poli, M., Gadea, A., Lenzi, S., Bazzacco, D., Lunardi, S., Rossi-Alvarez, C., Ur, C.A., and Medina, N. Wed . "High-spin octupole yrast levels in {sup 216}Rn{sub 86}". United States. doi:10.1103/PhysRevC.73.024314.
@article{osti_20771265,
title = {High-spin octupole yrast levels in {sup 216}Rn{sub 86}},
author = {Debray, M.E. and Escuela de Ciencia y Tecnologia, Universidad de San Martin and Davidson, J. and Davidson, M. and Kreiner, A. J. and Cardona, M. A. and Escuela de Ciencia y Tecnologia, Universidad de San Martin and CONICET, 1033 Buenos Aires and Hojman, D. and CONICET, 1033 Buenos Aires and Napoli, D.R. and De Angelis, G. and De Poli, M. and Gadea, A. and Lenzi, S. and Bazzacco, D. and Lunardi, S. and Rossi-Alvarez, C. and Ur, C.A. and Medina, N.},
abstractNote = {The yrast level structure of {sup 216}Rn has been studied using in-beam spectroscopy {alpha}-{gamma}-{gamma} coincidence techniques through the {sup 208}Pb({sup 18}O, 2{alpha}2n) reaction in the 91-93 MeV energy range, using the 8{pi} GASP-ISIS spectrometer at Legnaro. The level scheme of {sup 216}Rn resulting from this study shows alternating parity bands only above a certain excitation energy. From this result, the lightest nucleus showing evidence of octupole collectivity at low spins is still {sup 216}Fr, thereby defining the lowest-mass corner for this kind of phenomenon as N{>=}129 and Z{>=}87.},
doi = {10.1103/PhysRevC.73.024314},
journal = {Physical Review. C, Nuclear Physics},
number = 2,
volume = 73,
place = {United States},
year = {Wed Feb 15 00:00:00 EST 2006},
month = {Wed Feb 15 00:00:00 EST 2006}
}
  • High-spin yrast states in /sup 211/Rn have been identified. A 61/2/sup -/, 380 ns isomer found at 8856 keV is characterized as a core-excited configuration. The average shape of the yrast line is smoother behavior than that of its neighbor /sup 212/Rn. This difference is attributed to the presence of the neutron hole.
  • The structures of some recently observed high-spin isomers in {sup 213}Rn are considered. Octupole-mixed configurations are shown to account for the measured energies and electromagnetic properties of these levels.
  • We report the results of a study of the yrast excitation spectrum for /sup 216/Rn via the /sup 208/Pb(/sup 14/C,..cap alpha..2n)/sup 216/Rn reaction. Measurements of ..gamma..-..gamma.. coincidences, ..gamma..-ray angular distributions, and ..gamma..-x-ray coincidences were made. We propose a level spectrum up to J/sup ..pi../ = (10/sup +/) which does not exhibit the alternating parity structure observed in several isotopes of radium and thorium. From an examination of information on /sup 216/Rn and the neighboring nuclei, we can tentatively determine that the radon isotopes of masses 216 to 222 and the N = 128 isotones /sup 216/Ra and /sup 218/Th definemore » a lower mass boundary of a region beyond which static intrinsic reflection asymmetric shapes may exist in the nuclear ground states.« less
  • High-spin states in /sup 214/Rn and /sup 216/Ra have been studied by means of the reaction /sup 208/Pb(/sup 13/C, ..cap alpha.. 3n ..gamma..)/sup 214/Rn and /sup 208/Pb(/sup 13/C, 5n ..gamma..)/sup 216/Ra at beam energies in the range 75--95 MeV. In-beam spectroscopy techniques, including ..gamma..-decay excitation functions, ..cap alpha..-..gamma.. coincidences, ..gamma..-..gamma.. coincidences, ..gamma..-ray angular distributions, and pulsed-beam-..gamma.. timing, were utilized to establish level energies, ..gamma..-ray multipolarities, J/sup ..pi../ assignments, and isomeric lifetimes. Excited states with spins up to 23h in /sup 214/Rn and roughly-equal30h in /sup 216/Ra were observed. Isomers were found in /sup 214/Rn at 1625 keV (T/sub 1/2/ =more » 9 ns, J/sup ..pi../ = 8/sup +/), 1787 keV (22 ns, 10/sup +/), 3485 keV (95 ns, 16), 4509 keV (230 ns, 20), and 4738 keV (8 ns, 22), and in /sup 216/Ra at 1708 keV (8 ns, 8/sup +/) and 5868 keV (10 ns, approx.24). B(EL) values were deduced and compared to previously known lead-region electric transition rates. Shell-model calculations were performed and used to make configurational assignments. The absence of major ..cap alpha..-decay branching in the isomers is explained and the systematic behavior of N = 128 even-even nuclei is discussed.« less
  • The gamma decay of excited states in the nucleus {sup 100}Cd, which is two proton holes and two neutrons away from doubly magic (N=Z=50) {sup 100}Sn, has been studied with the Gammasphere array following the {sup 46}Ti({sup 58}Ni,2p2n) reaction at 215 MeV. Residues were identified by detection of evaporated charged particles in the Microball CsI array, by neutron detection in a set of liquid scintillator detectors, and by a tag on the delayed gamma-ray decay of the known 8{sup +} isomeric state. The level scheme has been extended up to 20({Dirac_h}/2{pi}) in angular momentum and to nearly 10 MeV inmore » excitation energy. The results are compared with shell-model calculations. (c) 2000 The American Physical Society.« less