Distribution of photon strength in nuclei by a method of two-step cascades

Conference · Mon Jan 01 00:00:00 EST 1990

OSTI ID:6431995

Becvar, F; Cejnar, P ^[1]; Chrien, R E ^[2]; Kopecky, J ^[3]

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1. Karlova Univ., Prague (Czechoslovakia). Fakulta Matematicko-Fyzikalni
2. Brookhaven National Lab., Upton, NY (USA)
3. Netherlands Energy Research Foundation, Petten (Netherlands)

The applicability of sum-coincidence measurements of two-step cascade {gamma}-ray spectra to the determination of photon strength functions at intermediate {gamma}-ray energies (3 or 4 MeV) is discussed. An experiment based on thermal neutron capture in Nd was undertaken at the Brookhaven National Laboratory High Flux Beam Reactor to test this model. To understand the role of various uncertainties in similar experiments a series of model calculations was performed. We present an analysis of our experimental data which demonstrates the high sensitivity of the method to E1 and M1 photon strength functions. Our experimental data are in sharp contradiction to those expected from an E1 photon strength distributed according to the classical Lorentzian form with an energy invariant damping width. An alternative distribution of Kadmenskij et al., which violates Brink's Hypothesis, is strongly preferred. 13 refs., 5 figs.

• Research Organization: Brookhaven National Lab., Upton, NY (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 6431995
• Report Number(s): BNL-45365; CONF-901057-23; ON: DE91005436; TRN: 91-000421
• Resource Relation: Conference: 7. international symposium on capture gamma-ray spectroscopy and related topics, Pacific Grove, CA (USA), 14-19 Oct 1990
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
GAMMA CASCADES
STRENGTH FUNCTIONS
NEODYMIUM 144 TARGET
NEUTRON REACTIONS
CAPTURE
EXPECTATION VALUE
GAMMA SPECTRA
GIANT RESONANCE
BARYON REACTIONS
FUNCTIONS
HADRON REACTIONS
NUCLEAR CASCADES
NUCLEAR REACTIONS
NUCLEON REACTIONS
RESONANCE
SPECTRA
TARGETS
651720* - Nuclear Properties & Reactions
A=90-149
Experimental
653003 - Nuclear Theory- Nuclear Reactions & Scattering