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Compound-Nucleus and Doorway-State Decays of β-Delayed Neutron Emitters ^{51,52,53}K
Z Y Xu1, R Grzywacz1,2, A Gottardo3,4
1Department of Physics and Astronomy, <a href="https://ror.org/00xzqjh13">University of Tennessee</a>, Knoxville, Tennessee 37996, USA.
Physical Review Letters
|August 9, 2024
Summary
We studied beta-delayed neutron emission (βn) in potassium isotopes. Most decays fit the compound nucleus model, but ^{53}K showed direct neutron emission, suggesting doorway state involvement.
Area of Science:
- Nuclear Physics
- Radioactive Decay Studies
Background:
- The mechanism of beta-delayed neutron emission (βn) is crucial for understanding nuclear structure and reactions.
- Bohr's 1939 hypothesis proposed that neutrons in the βn process originate from a structureless compound nucleus.
Purpose of the Study:
- To investigate the βn decay of ^{51,52,53}K isotopes.
- To test Bohr's compound nucleus hypothesis using experimental decay data.
- To elucidate the role of nuclear structure in βn emission.
Main Methods:
- Utilized the ISOLDE Decay Station at CERN for high-precision measurements.
- Quantified neutron and gamma-ray emission probabilities for ^{51,52,53}K precursors.
- Analyzed decay paths to determine the origin of emitted neutrons.
Main Results:
- Experimental data align with the compound nucleus model for most observed decay paths.
- A surprising deviation was observed in ^{53}K βn decay, contradicting Bohr's hypothesis.
- Preferential population of the first excited state in ^{52}Ca indicated direct neutron emission.
Conclusions:
- The study suggests that while the compound nucleus model applies to some βn decays, direct neutron emission is also significant.
- Observed non-statistical neutron emission is attributed to coupling with doorway states.
- The apparent compound nucleus decay arises from the collective effect of multiple doorway states.
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