Measurement of gamma-emission branching ratios for {sup 154,156,158}Gd compound nuclei: Tests of surrogate nuclear reaction approximations for (n,gamma) cross sections

Journal Article · Mon Mar 15 00:00:00 EDT 2010 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.81.034608· OSTI ID:21388887

Scielzo, N D; Escher, J E; Bernstein, L A; Bleuel, D L; Burke, J T; Dietrich, F S; Lesher, S R; Sheets, S A; Thompson, I J ^[1]; Allmond, J M; Beausang, C W ^[2]; Basunia, M S; Clark, R M; Fallon, P; Gibelin, J; McMahan, M A; Phair, L ^[3]; Goldblum, B L ^[4]; Norman, E B ^[1]; Rodriquez-Vieitez, E ^[3]

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1. Physical Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)
2. Department of Physics, University of Richmond, Richmond, Virginia 23173 (United States)
3. Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
4. Department of Nuclear Engineering, University of California, Berkeley, California 94720 (United States)

The surrogate nuclear reaction method can be used to determine neutron-induced reaction cross sections from measured decay properties of a compound nucleus created using a different reaction and calculated formation cross sections. The reliability of (n,gamma) cross sections determined using the Weisskopf-Ewing and ratio approximations are explored for the {sup 155,157}Gd(n,gamma) reactions. Enriched gadolinium targets were bombarded with 22-MeV protons and gamma rays were detected in coincidence with scattered protons using the Silicon Telescope Array for Reaction Studies/Livermore-Berkeley Array for Collaborative Experiments (STARS/LiBerACE) silicon and germanium detector arrays. The gamma-emission probabilities for the {sup 154,156,158}Gd compound nuclei were measured at excitation energies up to 12 MeV. It is found that the approximations yield results that deviate from directly measured {sup 155,157}Gd(n,gamma) cross sections at low energies. To extract reliable cross sections, a more sophisticated analysis should be developed that takes into account angular-momentum differences between the neutron-induced and surrogate reactions.

• OSTI ID: 21388887
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 81, Issue 3; Other Information: DOI: 10.1103/PhysRevC.81.034608; (c) 2010 The American Physical Society; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR MOMENTUM
APPROXIMATIONS
BRANCHING RATIO
COMPOUND NUCLEI
CROSS SECTIONS
DECAY
EMISSION
EXCITATION
GADOLINIUM
GADOLINIUM 154
GADOLINIUM 155
GADOLINIUM 157
GADOLINIUM 158
GAMMA DECAY
GAMMA RADIATION
GE SEMICONDUCTOR DETECTORS
MEV RANGE 10-100
NEUTRON REACTIONS
NEUTRONS
NUCLEAR REACTIONS
PROBABILITY
PROTONS
RELIABILITY
SILICON
STARS
TELESCOPES
YIELDS
BARYON REACTIONS
BARYONS
CALCULATION METHODS
DIMENSIONLESS NUMBERS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ELEMENTS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FERMIONS
GADOLINIUM ISOTOPES
HADRON REACTIONS
HADRONS
INTERMEDIATE MASS NUCLEI
IONIZING RADIATIONS
ISOTOPES
MEASURING INSTRUMENTS
METALS
MEV RANGE
NUCLEAR DECAY
NUCLEI
NUCLEON REACTIONS
NUCLEONS
RADIATION DETECTORS
RADIATIONS
RARE EARTH NUCLEI
RARE EARTHS
SEMICONDUCTOR DETECTORS
SEMIMETALS
STABLE ISOTOPES