The photodisintegration of 24Mg

doi:10.1016/0375-9474(83)90510-9

Nuclear Physics A

Volume 411, Issue 1, 12 December 1983, Pages 105-124

https://doi.org/10.1016/0375-9474(83)90510-9 Get rights and content

Abstract

The giant dipole resonance (GDR) of ²⁴Mg was studied by measuring two different types of decay spectra: (a) prompt de-excitation γ-rays emitted following photodisintegration, and (b) those of charged photoparticles. Energy-integrated (γ, n) and (γ, p) cross sections to specific residual states and also partial (γ, p) and (γ, α) cross sections are presented. The observed decay properties are discussed with reference to the 1p1h model, and the isospin purity of the GDR is assessed. Detailed comparison with theoretical models, however, indicates that the existing calculations fail to describe correctly both the deduced 1p1h composition and structure of the GDR.

References (33)

V.G. Neudatchin et al.
Phys. Lett.
(1964)
S.G. Nilsson et al.
Nucl. Phys.
(1962)
K. Bangert et al.
Nucl. Phys.
(1976)
J.E.M. Thomson et al.
Nucl. Phys.
(1977)
P.M. Endt et al.
Nucl. Phys.
(1978)
F. Ajzenberg-Selove
Nucl. Phys.
(1978)
J.T. Caldwell et al.
Phys. Rev. Lett.
(1967)
P.J.P. Ryan et al.
Nucl. Phys.
(1981)
P.M. Endt et al.
Atom. Nucl. Data Tables
(1974)
U.E.P. Berg et al., to be...
B.S. Dolbilkin et al.
Bull. Acad. Sci. USSR (phys. ser.)
(1966)

R.O. Nelson et al.

Phys. Rev.

(1972)

J. Dubach, private...

G.R. Satchler

Ann. of Phys.

(1958)

J.M. Irvine

G.E. Brown et al.

Phys. Rev. Lett.

(1959)

W.H. Bassichis et al.

Phys. Rev.

(1966)

Cited by (6)

The nuclear physics of muon capture
2001, Physics Report
We review the topic of muon capture in nuclei and show that significant nuclear physics is being learnt from recent experiments. The focus of many earlier experiments had been the particle physics and weak interactions aspects of the subject. Although these were useful confirmation of basic ideas, defining experiments mostly came from other areas. Thus, we focus on what can be learnt about nuclei especially 1⁺, 1⁻ and 2⁻ magnetic transitions. Valuable comparisons can be made to other charge exchange reactions such as (π⁻,γ), (π⁻,π⁰), (n,p), $(d,^{2} He)$ and $(t,^{3} He)$ . However, all those experiments have resolutions of 300 keV to 1 MeV, or even worse, so γ-ray studies of muon capture provide resolutions 100–1000 times better, and thus define the levels unambiguously. For even–even nuclei one can also compare to (e,e′) at 180°, or (p,p′) at forward angles, for which the resolution is reasonable, typically 50–100 keV, but isospin mixing complicates the comparison. With the recent substantial progress in Shell Model calculations, we anticipate significant developments in our understanding of nuclear structure in the next few years.
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,
- •
  - neutron, proton, or α-particle resonances,
- •
  - partial widths,
- •
  - single-nucleon transfer reactions,
- •
  - beta-decay,
- •
  - 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.
Partial photonucleon cross sections and the <sup>24</sup>Mg giant dipole resonance
1988, Nuclear Physics, Section A
The (γ, n_i) cross sections in the region of the giant dipole resonance (GDR) of the self-conjugate ²⁴Mg nucleus have been obtained on the basis of the experimental (γ, p_i) cross sections (i specifies states of the final nucleus) and the isospin symmetry of photonucleon decays. In the (γ, n_i), (γ, p_i) cross sections, the total photonucleon cross sections, and the photoabsorption cross sections, we have identified the components due to semidirect GDR decay using the ratios of the semidirect decay widths resulting from the R-matrix theory. In the integrated photoabsorption, photoproton, and photoneutron cross sections the probability of semidirect decays was found to be 57–67%, 45–60%, and 80–90%, respectively.
The semidirect decays dominate in the low-energy (<22 MeV) group of the GDR containing the transitions $1 d 2 s → 1 f 2 p and 1 p 12 → 1 d 2 s$ and the statistical decays dominate in the high-energy (> 22 MeV) group of the transitions $1 p_{32} → 1 d 2 s$ .
The giant dipole resonance in light nuclei and related phenomena
1986, Physics Reports
The present-day status of the giant dipole resonance (GDR) in light nuclei is discussed with main emphasis on the supermultiplet and configurational splitting of GDR, which are its most important features. A great wealth of experimental data, which confirm the existence of the above phenomenon are presented. Consideration is also given to the related problems, such as radiative pion capture and muon capture, spin-isospin dipole excitations, the role of the supermultiplet structure of nuclear levels in the formation of hypernuclear states in processes of the coherent substitution of hyperons for nucleons.
Deexcitation rays following the photodisintegration of O17
1989, Physical Review C
Photoproton decay of the E1 giant resonance in F19
1985, Physical Review C

^†: Present address.

View full text

The photodisintegration of 24Mg

Abstract

Phys. Lett.

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

Phys. Rev. Lett.

Nucl. Phys.

Atom. Nucl. Data Tables

Bull. Acad. Sci. USSR (phys. ser.)

Phys. Rev.

Ann. of Phys.

Phys. Rev. Lett.

Phys. Rev.

The photodisintegration of ²⁴Mg