Isomeric pair ^{95 m,g} Nb in the photonuclear reactions on ^natMo at the bremsstrahlung end-point energy of 38–93 MeV

Abstract

The natMo(γ,xnp)95m,gNb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40. The experiment was performed using the activation and off-line γ-ray spectrometric technique. The experimental isomeric yield ratio IR was determined for the reaction products 95m,gNb at the bremsstrahlung end-point energy E γmax range of 38–93 MeV. The obtained values of IR are in satisfactory agreement with the results of other authors and extend the range of previously known data. The theoretical values of the yields Y m,g(E γmax) and the isomeric yield ratio IR for the isomeric pair 95m,gNb from the natMo(γ,xnp) reaction were calculated using the partial cross-sections σ(E) from the TALYS1.95 code for six different level density models LD. 
At the investigated range of E γmax the theoretical dependence of IR on energy was
confirmed — the isomeric ratio smoothly increases with increasing energy. The comparison showed a noticeable difference (more than 3.85 times) of the experimental isomeric yield ratio relative to all theoretical estimates.

Study the Isomeric Ratios in Photonuclear Experiments on the Lue-40 Linac RDC “Accelerator” NSC Kipt

“…Calculation in TALYS1.95, LD1, LD4-6. Experiment: black - [27] In work [28] the experimental isomeric ratio IR was determined for the reaction products 95m,g Nb at the bremsstrahlung end-point energy E γmax range of 38…93 MeV. The obtained values of IR are in satisfactory agreement with the results of other authors and extend the range of previously known data.…”

“…The results obtained are presented in order of increasing atomic charge (mass): Zr [26], Nb [27], Mo [28], Rh [29], Ag [30 -32], In [30,31], Sb [33 -35], Ta [36].…”

“…Isomeric ratio IR for the reaction products from the nat Mo(γ,xnp) 95m,g Nb reaction. Experimental results: blue circles - [28], square - [60], red empty circles - [59], black circles - [24]. The curvecalculation in the code TALYS1.95, LD3, divided by a factor of 3.85 Fig.…”

“…(3) In the case of an internal transition between the metastable and ground states, it is necessary to take into account the accumulation of the ground state of the nucleus due to the decay of the metastable state. The formula for IR becomes more complex, for example, see [28,57].…”

“…This article presents the results of the IR measurements obtained at linear accelerator LUE-40 RDC "Accelerator" NSC KIPT for the target nuclei: Zr [26], Nb [27], Mo [28], Rh [29], Ag [30][31][32], In [30,31], Sb [33][34][35], and Ta [36]. The calculations of theoretical IRs were performed using cross-sections of the TALYS1.95 code for six different level density models.…”