Discovery of low-lying E1 and M1 strengths in {sup 232}Th

Journal Article · Tue Mar 15 00:00:00 EDT 2011 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.83.034615· OSTI ID:21499509

Adekola, A S; Hammond, S L; Hill, A; Karwowski, H J ^[1]; Angell, C T ^[2]; Howell, C R; Kwan, E ^[3]; Kelley, J H ^[3]

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1. Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599 (United States)
2. Department of Nuclear Engineering, University of California, Berkeley, California 94720 (United States)
3. Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States)

Properties of low-energy dipole states in {sup 232}Th have been investigated with the nuclear resonance fluorescence technique. The present work used monoenergetic {gamma}-ray beams at energies of 2-4 MeV from the high-intensity {gamma}-ray source at Triangle Universities Nuclear Laboratory. Over 40 transitions corresponding to deexcitation to the ground state and first excited state were observed for the first time. Excitation energies, integrated cross sections, decay widths, branching ratios, and transition strengths for those states in {sup 232}Th were determined and compared with quasiparticle random-phase-approximation calculations. A large number of E1 transitions were observed for the first time in actinide nuclei with summed strength of 3.28(69)x10{sup -3} e{sup 2} fm{sup 2}. The observed summed M1 strength of 4.26(63){mu}{sub N}{sup 2} is in good agreement with the other actinides and with the systematics of the scissors mode in deformed rare-earth nuclei.

• OSTI ID: 21499509
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 83, Issue 3; Other Information: DOI: 10.1103/PhysRevC.83.034615; (c) 2011 American Institute of Physics; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDES
BRANCHING RATIO
CROSS SECTIONS
DE-EXCITATION
DIPOLES
E1-TRANSITIONS
EXCITATION
GAMMA RADIATION
GAMMA SOURCES
M1-TRANSITIONS
MEV RANGE 01-10
NUCLEAR DECAY
RANDOM PHASE APPROXIMATION
RARE EARTH NUCLEI
RESONANCE FLUORESCENCE
THORIUM 232
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
APPROXIMATIONS
CALCULATION METHODS
DECAY
DIMENSIONLESS NUMBERS
ELECTROMAGNETIC RADIATION
ELEMENTS
EMISSION
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
FLUORESCENCE
HEAVY NUCLEI
INTERMEDIATE MASS NUCLEI
IONIZING RADIATIONS
ISOTOPES
LUMINESCENCE
METALS
MEV RANGE
MULTIPOLE TRANSITIONS
MULTIPOLES
NUCLEI
PHOTON EMISSION
RADIATION SOURCES
RADIATIONS
RADIOISOTOPES
SPONTANEOUS FISSION RADIOISOTOPES
THORIUM ISOTOPES
YEARS LIVING RADIOISOTOPES