Influence of reaction channel on the isomeric cross-section ratio
Summary The influence of reaction channel on the isomeric cross-section ratio was investigated by analysing the experimental data on the reactions 52Cr(p, n)52m,gMn, 52Cr(3He, t)52m,gMn, 54Fe(d, α)52m,gMn, 54Fe(n, t)52m,gMn and 54Fe(3He, α p)52m,gMn over the incident particle energy range extending up to 35 MeV. The influence is most pronounced when the channels differ widely, for example (p, n) and (3He, t) processes, i.e. when the reaction mechanisms are different. The nuclear model calculational code EMPIRE-II described the isomeric cross-section ratio rather well in the case of a simple nucleon emission reaction, but not when complex reaction channels were involved.
The isomeric ratios in photonuclear reactions of natural barium induced by bremsstrahlungs with endpoint energies in the giant dipole resonance region
We have determined the isomeric ratios in 130Ba(γ, n)129m,gBa, 132Ba(γ, n)131m,gBa and 134Ba(γ, n)133m,gBa photonuclear reactions of natural barium induced by bremsstrahlungs with end-point energies in the giant dipole resonance region. The investigated samples were irradiated at electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, Dubna, Russia. The gamma spectra of the samples irradiated were measured with spectroscopic system consisting of 8192 channel analyzer and high-energy resolution (180 keV at gamma ray 1332 keV of 60Co) HP(Ge) semiconductor detector Canberra. The GENIE2000 (Canberra) computer program was used for data processing. The results were discussed and compared with those of other authors.
Microscopic and conventional optical model analysis of neutron elastic scattering at 21.6 MeV over a wide mass range
Abstract Differential fast neutron elastic scattering angular distributions have been measured at 21.6 MeV for the natural elements Mg, Al, Si, S, Ca, Cr, Fe, Co, Ni, Y, Ce, Pb r (radiogenic lead) and Bi by employing pulsed beam time-of-flight techniques. The energy resolution was about 0.5 MeV (FWHM) throughout the measurements. The experimental data have been analysed in terms of a standard phenomenological spherical optical model. Potential depths and geometrical parameters were determined from individual best fits to the data. Volume integrals of the real and imaginary parts of the potential were calculated using these parameters. A similar technique was utilized to calculate root mean square radii of the real potential, from which radii of point matter distributions were obtained for comparison with α-particle scattering data at 166 MeV and with charge distribution radii from electron scattering. Microscopic folding models for the optical potential according to Jeukenne, Lejeune and Mahaux, Brieva and Rook, and Yamaguchi et al . have been tested by calculating angular distributions, volume integrals and root mean square radii for the real and imaginary potential parts. The results of these calculations are compared with those of the phenomenological analyses. The microscopic potentials have also been intercompared by studying introduced normalizing parameters of the real and imaginary potential parts as well as isovector and isoscalar contributions to the volume integrals.