High-energy photodisintegration of lithium

doi:10.1016/0375-9474(70)90778-5

Nuclear Physics A

Volume 153, Issue 2, 21 September 1970, Pages 401-408

https://doi.org/10.1016/0375-9474(70)90778-5 Get rights and content

Abstract

The spectra of fast photoprotons from the reaction ⁷Li(γ, p)⁶He have been measured at 14 bremsstrahlung end-point energies from 50 to 84 MeV. The observed kinematical behaviour and the comparison of the measured cross sections with the theory shows that the threshold photoprotons are emitted through a direct interaction of the photon with the 1p proton, while a quasi-deuteron absorption is probably mostly responsible for the emission of lower-energy protons.

References (17)

S. Ferroni et al.
Nucl. Phys.
(1967)
G. Manuzio et al.
Nucl. Phys.
(1969)
A. Johansson et al.
Nucl. Phys.
(1963)
B.C. Cook
Nucl. Instr.
(1963)
M. Bouten et al.
Nucl. Phys.
(1968)
J. Kruger et al.
Nucl. Phys.
(1969)
A. Watt
Phys. Lett.
(1968)
J. Garvey et al.
Nucl. Phys.
(1967)

There are more references available in the full text version of this article.

Cited by (12)

Lithium photodisintegration with unpolarized photon beams at near threshold energies
2022, Materials Today: Proceedings
Citation Excerpt :
An attempt was made to calculate thermonuclear reaction rates addressing the primordial 7Li abundance [22]. Experimental studies on photodisintegration of 7Li using bremsstrahlung photons and electrodisintegration have been carried out in 1970′s [23]. The ground state cross section has been calculated 4.4 MeV ≤ Eγ ≤ 10 MeV at Triangle Universities Nuclear Laboratory (TUNL) [24].
The study of photonuclear reactions with lithium targets i.e. photodisintegration of lithium in addition to other photonuclear reactions is of considerable interest to the fields of nuclear physics, astrophysics, laser physics and several applications such as non - destructive testing of nuclear materials. We propose to study photodisintegration of lithium with unpolarized photon beams at near threshold energies. Our model independent theoretical approach, which makes use of irreducible tensor techniques, is well suited for making predictions on the spin observables as well as the differential cross section. In this paper we analyze the reaction channel ⁷Li + γ → ⁶Li + n by using unpolarized photons.
High energy photoprotons from light nuclei
1976, Nuclear Physics, Section A
In this paper we present (γ,p) measurements for the lithium, beryllium and carbon nuclei in the photon energy range 60–100 MeV. A single-difference bremsstrahlung unfolding technique is used to produce effectively monochromatic photons of energies 60±1, 80±1 and 100±1 MeV. At 60 MeV proton spectra were obtained at θ_p = 45° over a range of residual nuclear excitation energies from 0 to 30 MeV for ^6,7Li and 0–20 MeV for ⁹Be and ¹²C. Also the angular distribution between 30° and 150° was measured for the highest energy protons from ^{6, 7}Li and ¹²C at E_γ = 60 MeV, for ⁷Li and ¹²C at E_γ = 80 MeV and for ¹²C at E_γ = 100 MeV. Qualitative conclusions concerning the possible reaction mechanism may be drawn from the observed proton spectra, viz. that they support the hypothesis of a direct interaction of the photon with a proton in a shell-model (1s or 1p) orbit. However, simple shell-model wave functions are found to have insufficient amplitude in the high momentum region to account for the data. A phenomenological calculation which includes nucleon-nucleon correlations by means of the Jastrow model represents only approximately the energy and angular dependence of the measured cross sections.
Investigation of the 16O(γ, n)15O and 12C(γ, n)11C reaction at photon energies between 150 MeV and 63 MeV
1974, Nuclear Physics, Section A
Measurements of the energy distribution of high energy neutrons emitted in the photo-disintegration of ¹⁶O and ¹²C have been performed with a time of flight method for four angles (40.2°, 90°, 113.5°, 142.2°) using the electron beam (60 MeV ≦ E ≦ 150 MeV) of the Mainz University Electron Linac. Neutron spectra for “monochromatic” photons were obtained by a difference method. The cross sections extracted from these spectra show a pronounced forward asymmetry and decrease rapidly with increasing photon energy. The data can be described by a phenomenological quasi-deuteron model.
Proton spectra from the 6,7Li(γ,p) 5,6He reactions at E<inf>γ</inf> = 60 MeV
1973, Physics Letters B
Angular distributions of high energy photoprotons from 6Li(γ, p)
1972, Physics Letters B
(γ, p) angular distributions have been studied for photon energies E_γ ⩾ 100 MeV on the basis of a shell model modified by short-range dynamical correlations (SRC's)between the nucleons. It is shown that short-range correlations affect the magnitude as well as the shape of the proton angular distributions. It turns out that the shell model underestimates the experimental data appreciably, whereas the inclusion of SRC's tends to reproduce the measured angular distribution.
Magnetization distribution of the 7Li nucleus as obtained from electron scattering through 180°. The electric quadrupole moment of 7Li
1971, Nuclear Physics, Section A
Cross sections for scattering of electrons from the ground state doublet of ⁷Li have been measured in the energy range of 25 to 90 MeV with an energy resolution better than 200 keV. From the cross sections for transverse elastic scattering measured at 180° the rms radius of the ground state magnetization density distribution has been determined: $〈r^{2} 〉_{M}^{12} = 2.98 ± 0.05 fm$ . The value of the reduced transition probability for M1 excitation of the first excited level has been determined from the ratio of transverse inelastic and elastic cross sections at 180°. The result [B(M1, ↑; 478 keV)=2.50±0.12 μ_N²] agrees very well with the result of lifetime measurements. The cross sections for longitudinal (C2) excitation of this level have been extracted from scattering through angles of 90° to 150°. The measured reduced transition probability [B(C2, ↑; 478 keV)=7±4 fm⁴] is compared with the values obtained by several other experimental methods. In a shell-model analysis our data can be considered to measure the size of the 1p shell. The resulting value (a_1p=1.90±0.03 fm) is much larger than the one determined from earlier electron scattering experiments, where the 478 keV level was not resolved. A relative measurement of the longitudinal elastic scattering from ⁷Li and from ⁶Li showed no isotopic effect on the rms charge radius: $〈r^{2} 〉_{7}^{12} /〈r^{2} 〉_{6}^{12} =1.001±0.008$ . Accepting the measured rms charge radius for ⁶Li this corresponds to a_1s=a_1p=1.90 fm for ⁷Li reconfirming the above value. The data are compared with shell-model and projected Hartree-Fock calculations.

View all citing articles on Scopus

^†: Supported by the Istituto Nazionale di Fisica Nucleare.

View full text

Article preview

Nuclear Physics A

Abstract

References (17)

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

Nucl. Instr.

Nucl. Phys.

Nucl. Phys.

Phys. Lett.

Nucl. Phys.

Cited by (12)

Lithium photodisintegration with unpolarized photon beams at near threshold energies

High energy photoprotons from light nuclei

Investigation of the <sup>16</sup>O(γ, n)<sup>15</sup>O and <sup>12</sup>C(γ, n)<sup>11</sup>C reaction at photon energies between 150 MeV and 63 MeV

Proton spectra from the <sup>6,7</sup>Li(γ,p) <sup>5,6</sup>He reactions at E<inf>γ</inf> = 60 MeV

Angular distributions of high energy photoprotons from <sup>6</sup>Li(γ, p)

Magnetization distribution of the <sup>7</sup>Li nucleus as obtained from electron scattering through 180°. The electric quadrupole moment of <sup>7</sup>Li