Photoneutron Cross Sections forSn116,Sn117,

Abstract

Monochromatic photons obtained from the annihilation in flight of fast positrons were used to measure photoneutron cross sections for a number of tin isotopes and indium. Total cross sections for Sn 116 , Sn 117 , Sn 118 , Sn 119 , Sn 120 , Sn 124 , and In have peak values of 266, 254, 255, 253, 280, 283, and 266 mb at energies of 15.67,15.66,15.60,15.54,15.40,15.18, and 15.63 MeV, respectively. The respective integrated cross sections were found to be 1.67, 1.89, 1.85, 2.00, 2.07, 2.01, and 1.88 MeV b; while the respective (7, In) integrated cross sections were 0.414, 0.475, 0.531, 0.598, 0.673, 0.670, and 0.509 MeV b. Single-nucleon effects on the giant resonance were examined, and shell effects have been determined. Other nuclear quantities determined include nuclear level densities, pairing energies, and integrated moments. 7 The decays of 1116, 118, 120, 122 have been studied by use of isotopically separated sources produced by proton spallation of lanthanum. Ge(Li) 7-ray singles spectra and Ge(Li)-Ge(Li) coincidence spectra have been obtained and used in constructing level schemes for the corresponding Te daughters.

Soft structures ofγ-ray strength functions studied with the Oslo method

“…Further investigations are needed both on the upbend phenomenon and the resonance-like structure of the Sn isotopes. [19], and from (γ, x) photonuclear reactions (red open triangles [20], stars [21], and blue open squares [22]). The sum of the GLO E1 strength and the M1 spin-flip resonance is shown as a solid line.…”

Photoneutron reaction cross sections from various experiments – analysis and evaluation using physical criteria of data reliability

“…The typical examples of F 1,2 energy dependencies for 116 Sn data obtained at Livermore [7] and Saclay [10] are presented in Fig. 2 in comparison with the results of correspondent calculations in the combined model of photonuclear reactions [11].…”

“…The reason The data reliability criteria ratios F 1 (a) and F 2 (b) for 116 Sn obtained for experimental cross sections: trianglesLivermore data [7], squares -Saclay data [10], lines -results of calculations in model [11]. could be the incorrect assignment of neutrons to the (γ , 2n) channel instead of the (γ , 1n) channel and to the (γ , 1n) channel instead of (γ , 3n) channel, respectively, because of errors in neutron multiplicity determination using its kinetic energy measuring [1] based on the supposition that energy of neutron from (γ , 1n) reaction is larger than energies of both neutrons from (γ , 2n) reaction.…”

Determination of radiative neutron capture cross sections for unstable nuclei by the γ-ray strength function method

“…Figure 2 shows photoneutron cross sections for 117 Sn [10][11][12]. Also shown in the figure are the standard Lorentzian model [13] and Skyrme Hartree-Fock Bogoliubov (HFB) plus quasiparticle random-phase approximation model (QRPA) [14] of the primary E1 γSF.…”