Investigation of ?-induced reactions on niobium and tantalum

Abstract

Excitation functions of (c~,xnyp) reactions on 93Nb with y<6 and x<10 have been measured in four different irradiations from 16 to 171 MeV bombarding energy by Ge(Li) spectroscopy of the residual activity of stacked foils. Similarly, previous measurements of 18~Ta(c~, xn yp) reactions from 15 to 103 MeV were extended up to 170 MeV eenergy for residual nuclei with y<4 and x<12. Including isomeric states a total number of 37 residual activities could be identified in 93Nb+e. From the rather complex y-decay spectra altogether 28 different excitation functions of sizable length could be established. For 18XTa + ~ 10 different residual activities were analyzed so that together with the former data a set of 15 excitation functions is available. The whole set of excitation functions provides a large data basis for probing the validity of combined equilibrium and preequilibrium reaction models in a wide energy range. NuclearReactions: 93Nb(e, xn yp), E~ = 16-170.7 MeV, x ~ 10, y < 6, ISlTa(e, xnyp), x<12, y<4; measured a(E) by activation of stacked foils, natural targets.

Excitation functions and isomeric ratios in the reaction130Te (?,xpyn) for ?-particle energies between 15 and 37 MeV

“…The relative number of nuclei from one target, which have undergone nuclear reactions is about 6.5x10 -s. Because of the small target thickness ( < 1 mg/cm 2) and the relatively small e-particle energy (<37 MeV), the cross section corrections due to reactions with secondary particles [2] are negligible. In principle the reaction 130Te (n, 2 n) ~ 29Te from secondary neutrons might interfere with the determination of the 13~ ~.n)t29Te excitation functions.…”

“…Accoridng to the first one the calculation was based on the initial number of residual nuclei of certain type at the end of the irradiation, which was determined by fitting the decay curve. In the second type one ~,-line area and formulae similar to those used in [2] were employed. For isotopes with half lives smaller or comparable to the irradiation time, the irradi- Table 1.…”

“…With few exceptions [1], no sufficient number of reactions exists in which the (e, p) and (:~, n) excitation functions have been simultaneously studied. The reason is that most of the recent investigations are aimed to present excitation functions for many exit channels, which start from much higher energies [2,3]. Such studies contribute a lot for understanding the processes of multi nucleon emission at higher excitation energies, but usually do not contain enough experimental points at energies around the threshold for channels in which one or two particles are emitted.…”

Inclusive and exclusive preequilibrium spectra in a model of independently interacting excitons

“…For the helium projectiles angular momentum effects are discussed in the frame of the s-wave approximation, and isomere yields are predicted. Selecting experiments with high bombarding energies the theoretical analyses also include the previously published excitation functions on 93Nb and *8*Ta from 11 to 172 MeV [29].…”

Large pre-equilibrium contribution inα+natNiinteractions at≈8−40Yadav1, Singh2, Sharma3 et al. 2008Phys. Rev. C12030View full textAdd to dashboardCite

“…(v) During irradiation of the stack, the beam traverses the thickness of the material, thus reducing the initial beam intensity. It is estimated that the error from this decrease in beam intensity is 2%, as suggested by Ernst et al [25]. The overall errors in the present measurement [27], which takes both equilibrium and PE decay processes into account, and are shown in Figs.…”