Isomeric pair ${^{95\rm m,g}\rm{Nb}}$ in photonuclear reactions on $^{\rm nat}$Mo at end-point bremsstrahlung energy of 35-95 MeV

Author:

I. S. Timchenko, O. S. Deiev, S. M. Olejnik, S. M. Potin, V. A. Kushnir, V. V. Mytrochenko, S. A. Perezhogin, V. A. Bocharov

Keyword:

Nuclear Experiment, Nuclear Experiment (nucl-ex)

journal:

Chin. Phys. C47, no.12,124002 (2023)

date:

2023-08-03 16:00:00

Abstract

The ${^{\rm nat}\rm{Mo}}(\gamma,x\rm np)^{95\rm m,g}$Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40. Experiment was performed using the activation and off-line $\gamma$-ray spectrometric technique. The experimental isomeric yield ratio $d(E_{\rm{\gamma max}}) = Y_{\rm m}(E_{\rm{\gamma max}}) / Y_{\rm g}(E_{\rm{\gamma max}})$ was determined for the reaction products $^{95\rm m,g}\rm{Nb}$ at the end-point bremsstrahlung energy $E_{\rm{\gamma max}}$ range of 35-95 MeV. The obtained values of $d(E_{\rm{\gamma max}})$ are in satisfactory agreement with the results of other authors and extend the range of previously known data. The theoretical values of the yields $Y_{\rm m,g}(E_{\rm{\gamma max}})$ and the isomeric yield ratio $d(E_{\rm{\gamma max}})$ for the isomeric pair $^{95\rm m,g}\rm{Nb}$ from the ${^{\rm nat}\rm{Mo}}(\gamma,x\rm np)$ reaction were calculated using the partial cross-sections $\sigma(E)$ from the TALYS1.95 code for six different level density models $LD$. The comparison showed a noticeable excess (more than 3.85 times) of the experimental isomeric yield ratio over all theoretical estimates. At the investigated range of $E_{\rm{\gamma max}}$ the theoretical dependence of $d(E_{\rm{\gamma max}})$ on energy was confirmed - the isomeric yield ratio smoothly decreases with increasing energy.

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