Giant resonances and fine structure in Si28 from the Al27(p,γ)Si28 reaction

Singh, P. P.; Segel, R. E.; Meyer-Schützmeister, L.; Hanna, S. S.; Allas, R.G.

doi:10.1016/0029-5582(65)90326-3

Cited by 112 publications

(13 citation statements)

References 33 publications

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“…Figure 3 indicates the existence of a correlation between the peak energies in the (γ , abs) and (γ, p 0 ) reactions. The peak energies deduced from the data by Singh et al 5) are also shown in 14) and 28 Si(γ , n) 15) data, in which the energy shift of about 150 keV was reported relative to the previous (γ , abs) data. The intermediate fourpeak structures in 28 Si agree well with each other for the (γ, p), (γ, n), and (γ , abs) reactions.…”

Section: Methodsmentioning

confidence: 84%

“…The open circles in Fig. 3 show the 28 Si(γ , p 0 ) cross section deduced from the data of Singh et al 5) for the ( p, γ 0 ) reaction using the detailed balance relation:…”

Section: Methodsmentioning

confidence: 99%

“…The previous study 3) of the 28 Si(γ , abs) reaction at Maintz with the energy resolution of about 1% resolved the GDR into four intermediate peaks, whose positions and strengths were qualitatively explained by a one-particle and one-hole (1p-1h) model. 4) The existence of the finer structure than the intermediate one at the GDR region was revealed in the 28 Si(γ, p 0 ) cross section from the study of the inverse reaction 27 Al( p, γ 0 ) 28 Si measured at 15 keV intervals, 5) and interpreted in terms of quantum fluctuations. 6) Yale group also showed the existence of the fine structure in their 28 Si(γ , n 0 ) results 7) using a timeof-flight spectrometer with a resolution of 7 keV at a neutron energy of 1 MeV rising to about 60 keV at 4 MeV.…”

Section: Introductionmentioning

confidence: 99%

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Fine Structure of Giant Resonance in the²⁸Si(γ, abs) Reaction

Harada¹,

Furutaka²,

Ohgaki

et al. 2001

Journal of Nuclear Science and Technology

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The photo-absorption cross section for 28 Si has been measured in the energy range 17.5-21.5 MeV, using a highresolution high-energy photon spectrometer and laser Compton photons. Four intermediate structure peaks in the giant dipole resonance of 28 Si have been resolved into about thirty fine-structure peaks. The comparison of the observed structure with those in (γ, p 0 ) and (γ, n 0 ) reactions shows that the energies of the fine structure peaks in (γ , abs) reaction have a correlation with those in both of the (γ, p 0 ) and (γ, n 0 ) reactions. 465(BGO) anti-coincidence shields. The experimental arrangement is described in Refs. 1) and 2). A natural silicon target (92.18% in 28 Si) was used of the thickness 137.4 g/cm 2 . After the measurement of the 28 Si target, the energy distribution of the LCP beam was measured with a blank target instead of the 28 Si target.The photon energy was calibrated with a 60 Co source (E γ =1.173 and 1.333 MeV) and the 15.11 MeV peak in 13 C. 1) The error in E γ was estimated as less than 0.1% for the energy of about 20 MeV. The LCP beam was obtained using a CW Nd:YVO 4 laser beam (λ=532 nm and the power 1-5 W) and the electron storage ring TERAS. 11) The energy of the stored electron beam was 793 MeV and the stored current was 5-120 mA. The lead collimator of 150 mm in length with a hole of 4.0 mmφ was placed along the LCP beam axis to cut off the low energy tail of the LCP beam. Figure 1 shows the transmitted-photon spectra, Y( 28 Si) (•) and Y(blank) (•), of the HHS for the 28 Si and blank targets, respectively. Many absorption dips are shown in the Y( 28 Si) spectrum, whereas there is no significant absorption dip in the Y(blank) spectrum. This means the absorption dips originate in the photo-absorption by the 28 Si target. The (γ , abs) cross section is given by III. Results and Discussionwhere ρ and l mean the atomic density and the length of the 28 Si target. The U and U 0 are obtained by unfolding the observed spectra Y( 28 Si) and Y(blank), respectively, with the response functions 10) of HHS calculated using the EGS4 simulation code. 12) The c in Eq. (1) is a normalization constant for the observed spectrum for the blank target. The σ atom (E γ ) is the photo-atomic cross section that is well known to have smooth energy dependence and tabulated. 13) The (γ , abs) cross section for 28 Si obtained in the present experiments is shown as a function of excitation energy by the closed circles in Fig. 2. The cross section includes "contami-

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Section: Methodsmentioning

confidence: 84%

“…The open circles in Fig. 3 show the 28 Si(γ , p 0 ) cross section deduced from the data of Singh et al 5) for the ( p, γ 0 ) reaction using the detailed balance relation:…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Fine Structure of Giant Resonance in the²⁸Si(γ, abs) Reaction

Harada¹,

Furutaka²,

Ohgaki

et al. 2001

Journal of Nuclear Science and Technology

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“…In this case, one may suppose that interactions will occur and that the nucleon emitted in a photonuclear reaction may well not be the one excited in the radiative absorption. This proposition is supported by the work of Singh et al (1965) on the reaction 27 Al(p, YO)2 8Si. They found that the angular distribution of emitted y-rays was consistent with the absorption of p-wave protons, while the particle-hole model for 28Si indicates that the dominant transition is Ids/2 --+ If7/ 2.…”

Section: Introductionmentioning

confidence: 76%

An Interpretation of De-excitation Gamma Ray Measurements Following the Photodisintegration of 12C, 16O, and 40Ca

Spicer¹

1973

Aust. J. Phys.

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The relative populations of final states in photonuclear reactions for 12C, 160, and 40Ca are examined in the light of information on the known major configurations present in the wavefunctions of those final states, with the assumption that the nucleon excited in the radiation absorption process is in fact the one emitted. This assumption is investigated and found to be reasonable for 12C and 160 but not for 40Ca. The data on relative populations of final states are interpreted to give information on the relative strengths of configurations in the wavefunctions of the ground states of the three nuclei.

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“…Since that time many studies of light nuclei have been carried out. The structure seen in the cross sec tion varies from the very smooth shape of carbon (15) to the detailed structure of many discrete resonances as found In silicon (16) Most experimental studies of the photonuclear giant resonance employ one of three general methods. These methods are total absorption measure ments, direct measurements of the spectra of emitted particles, and activation measurements.…”

Section: Experimental Apparatus 29mentioning

confidence: 99%

A systematic study of the photo-disintegration of germanium isotopes

McCarthy

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Giant resonances and fine structure in Si28 from the Al27(p,γ)Si28 reaction

Cited by 112 publications

References 33 publications

Fine Structure of Giant Resonance in the²⁸Si(γ, abs) Reaction

Fine Structure of Giant Resonance in the²⁸Si(γ, abs) Reaction

An Interpretation of De-excitation Gamma Ray Measurements Following the Photodisintegration of 12C, 16O, and 40Ca

A systematic study of the photo-disintegration of germanium isotopes

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Giant resonances and fine structure in Si28 from the Al27(p,γ)Si28 reaction

Cited by 112 publications

References 33 publications

Fine Structure of Giant Resonance in the28Si(γ, abs) Reaction

Fine Structure of Giant Resonance in the28Si(γ, abs) Reaction

An Interpretation of De-excitation Gamma Ray Measurements Following the Photodisintegration of 12C, 16O, and 40Ca

A systematic study of the photo-disintegration of germanium isotopes

Contact Info

Product

Resources

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Fine Structure of Giant Resonance in the²⁸Si(γ, abs) Reaction

Fine Structure of Giant Resonance in the²⁸Si(γ, abs) Reaction