20Ne + n → 21Ne(T = 32) resonances

doi:10.1016/0375-9474(84)90182-9

Nuclear Physics A

Volume 424, Issue 2, 6 August 1984, Pages 200-220

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Abstract

$T = 32$ resonances in ²¹Ne have been studied in measurements of the total neutron cross section of ²⁰Ne using the 190 m neutron time-of-flight facility of the Karlsruhe Isochronous Cyclotron. The high time-of-flight resolution of 6.6 ps/m enabled the study of sharp $T = 32$ resonances in ²¹Ne with an effective energy resolution of up to 4000. Five $T = case3 2$ levels have been observed as sharp resonances allowing the precise determination of total width Λ, partial decay with Λ_no and resonance energy E_R. The c.m. resonance parameters of the first $T = 32$ state in ²¹Ne are E_R = 2098.6 ± 0.3 keV, Λ = 2.2 ± 0.5 keV and Λ_no = 0.21 ± 0.05 keV. Upper limits for the partial decay widths are deduced for those $T = 32$ levels which do not appear as resonance anomalies. A search for additional $T = 32$ states was undertaken. The resonance energies are discussed in the framework of the isbobaric mass multiplet equation. The decay widths are compared with shell-model predictions of isospin mixing and the systematics of isospin-non-conserving particle decays.

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Nuclear data sheets for A = 21
2004, Nuclear Data Sheets
This evaluation of A = 21 has been updated from previous evaluations published in Nucl. Phys. A 633 (1998), Nucl. Phys. A 521 (1990) 1, Nucl. Phys. A 529 (1991) 763, Nucl. Phys. A 564 (1993) 609, and Nucl. Phys. A 310 (1978) 1. Coverage includes properties of adopted levels and γ rays, decay-scheme data (energies, intensities and placement of radiations), and cross reference entries. The following tables continue the tradition of showing the systematic relationships between levels in A = 21.
Isospin-nonconserving particle decays in light nuclei
1992, Nuclear Physics, Section A
Isospin-nonconserving (INC) proton decays of nineteen $T = 32$ states in light nuclei (13 ⩽ A ⩽ 37) and alpha decays of three T = 2 states in 24 ⩽ A ⩽ 32 have been measured using high-energy resolution beams (FHWM about 600 eV) to produce excitation functions near these states for (p,p), (p,α) and (α,α) reactions. Resonances were analyzed using a helicity-amplitude formalism. The widths agree qualitatively with recent shell-model calculations that include isospin dependences in the hadronic part of the nucleon-nucleon force.
Energy levels of A = 21-44 nuclei (VII)
1990, Nuclear Physics, Section A
The experimentally determined properties of A = 21–44 nuclides are complied and evaluated with special emphasis on nuclear spectroscopy.
Separate tables for each of the nuclides reviewed present the available information about the following properties (in this order):
- •
  - excitation energies E_x,
- •
  - γ-ray branching ratios b(γ),
- •
  - γ-ray mixing ratios σ,
- •
  - lifetimes γ_m or widths Λ,
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  - neutron, proton, or α-particle resonances,
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  - partial widths,
- •
  - single-nucleon transfer reactions,
- •
  - beta-decay,
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  - arguments for spin and parity (J^π) and isospin (T) assignments.
For each nuclide a master table summarizing the “best” or adopted values for E_x, J^π; T and τ_m or Λ precedes the auxiliary tables listed above.
The review of each A-chain concludes with a discussion of isospin multiplets.
Figures are presented of the level schemes of all nuclei and, for each A-chain, an overview of the relative energies of the ground states and lowest analogue states of all nuclei in the chain.
Isospin-forbidden proton and neutron emission in 1s-0d shell nuclei
1986, Physics Letters B
Spectroscopic amplitudes for the decay of $T = 32$ states in A = 4n + 1 nuclei (21 ⩽ A ⩽ 37) by proton and neutron emission to the T = 0 ground state of A = 4n daughter nuclei are calculated and compared with experiment. The calculations were performed in the framework of the shell model using the full or nearly full 1s-0d configuration space and an isospin-nonconserving interaction which reproduces experimental isotopic mass shifts. Contributions due to mixing with individual parent and daughter states are analyzed. The question of periodicity in A for these amplitudes is addressed.
Neutron resonance parameters for Ne-20 (Neon)
2015, Neutron Resonance Parameters
Neutron decay of excited states in 21Ne populated in the 12C(13C,21Ne)4He reaction
2010, Journal of Physics G: Nuclear and Particle Physics

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^†: Permanent address: Ain Shams University, Cairo, Egypt.

^††: Now at Energiesystem Nord, Kiel, West Germany

^†††: Now at T $U ̈$ V Hessen, Frankfurt, West Germany.

^††††: Now at VDO, Babenhausen, West Germany.

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Nuclear Physics A

Abstract

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Nuclear data sheets for A = 21

Isospin-nonconserving particle decays in light nuclei

Energy levels of A = 21-44 nuclei (VII)

Isospin-forbidden proton and neutron emission in 1s-0d shell nuclei

Neutron resonance parameters for Ne-20 (Neon)

Neutron decay of excited states in 21Ne populated in the <sup>12</sup>C(<sup>13</sup>C,<sup>21</sup>Ne)<sup>4</sup>He reaction