arXiv subjects

V. V. Mitrochenko

Publications and source records attributed to V. V. Mitrochenko.

3 recordsLinked to original sources

arXiv2021

Cross-sections for the ${^{27}\!\rm{al}}(γ,\textit{x})^{22}\rm{na}$ multichannel reaction with the 28.3 mev difference of the reaction thresholds

The bremsstrahlung flux-averaged cross-sections $\langle{σ(E_{\rm{γmax}})}\rangle$ and the cross-sections per equivalent photon $\langle{σ(E_{\rm{γmax}})_{\rm{Q}}}\rangle$ were first measured for the photonuclear multichannel reaction ${^{27}\!\rm{Al}}(γ,\textit{x})^{22}\rm{Na}$ at end-point bremsstrahlung gamma energies ranging from 35 MeV to 95 MeV. The experiments were performed with the beam from the NSC KIPT electron linear accelerator LUE-40 with the use of the $γ$-activation technique. The bremsstrahlung quantum flux was calculated with the program GEANT4.9.2 and, in addition, was monitored by means of the $^{100}\rm{Mo}(γ,n)^{99}\rm{Mo}$ reaction. The flux-averaged cross-sections were calculated using the partial cross-section $σ(E)$ values computed with the TALYS1.95 code for different level density models. Consideration is given to special features of calculating the cross-sections $\langle{σ(E_{\rm{γmax}})}\rangle$ and $\langle{σ(E_{\rm{γmax}})_{\rm{Q}}}\rangle$ for the case of the final nucleus $^{22}\rm{Na}$ production in the $^{27}\!\rm{Al}$ photodisintegration reaction via several partial channels $\textit{x}$: $\rm{n}α+ dt + npt + 2n{^{3}\rm{He}} + n2d + 2npd + 2p3n$.

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arXiv2021

Photoneutron Reactions $^{181}\rm{Ta}(γ,\textit{x}n; \textit{x} = 1 ÷8)^{181-\textit{x}}\rm{Ta}$ AT $E_{\rm{γmax}}$ = 80 $÷$ 95 MeV

The bremsstrahlung flux-averaged cross-sections $\langle{σ(E_{\rm{γmax}})}\rangle$ for the $^{181}\rm{Ta}(γ,\textit{x}n; \textit{x} = 1 ÷8)^{181-\textit{x}}\rm{Ta}$ photoneutron reactions have been measured at end-point bremsstrahlung energies ranging from 80 MeV to 95 MeV. The measurements were performed with the beam from the NSC KIPT electron linear accelerator LUE-40 using the residual $γ$-activity method. The theoretical $\langle{σ(E_{\rm{γmax}})}\rangle$ values were computed using the cross-sections $σ(E)$ from TALYS1.9 code. A comparison between the measured cross-sections $\langle{σ(E_{\rm{γmax}})}\rangle$ and the theoretical values has demostrated their good agreement for the reactions with escape of up to 6 neutrons, and substantial differences for the $(γ,7\rm{n})$ and $(γ,8\rm{n})$ reactions. Isomeric ratios of the average cross-sections $d(E_{\rm{γmax}})$ have been found for the $^{181}\rm{Ta}(γ,3n)^{178g,m}\rm{Ta}$ reaction products. The results have been compared with the literature data and the computations based on TALYS1.9 code.

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arXiv2021

Photoneutron reactions on $^{\text{93}}$Nb at $E_{γ\text{max}}$=33-93 MeV

The bremsstrahlung flux-averaged cross sections for the photoneutron reactions $^{\text{93}}$Nb($γ$,xn;x=1-5)$^{\text{(93-x)m,g}}$Nb were measured in the range of boundary energies of bremsstrahlung $γ$-quanta $E_{γ\text{max}}$=33-93 MeV with a step $ΔE_{γ\text{max}}\approx $ 2 MeV. The isomeric ratios of the average cross-sections of the products of the reactions $^{\text{93}}$Nb ($γ$ ,4n)$^{\text{89m,g}}$Nb and $^{\text{93}}$Nb($γ$,5n)$^{\text{88m,g}}$ Nb were determined in the energy ranges $E_{γ\text{max}}$ = 50-93 and 70-93 MeV, respectively. The experiments were carried out on the beam of the linear electron accelerator LU-40 of the Science and Research Establishment (SRE) "Accelerator" at National Science Center Kharkov Institute of Physics and Technology (NSC KIPT) using the method of induced activity. Calculations of the cross sections, average cross sections, and isomeric ratios of the reaction products were performed using the TALYS 1.9 code with default parameters and the GEANT4 code. The tendency of a more successful description of the average cross sections of photoneutron reactions with the formation of final odd-even Nb nuclei than odd-odd Nb nuclei is revealed. The experimental average cross sections for the reactions ($γ$,2n) and ($γ$,4n) are in good agreement with theory, while in the case of reactions ($γ$,n), ($γ$,3n), and ($ γ$,5n), some discrepancies are observed. The results obtained for the reactions ($γ$,n), ($γ$,3n) and ($γ$,4n) are in satisfactory agreement with the known literature data. The average cross sections for the reactions ($γ$,2n) and ($γ$,5n) and the isomeric ratios of the reaction products $^{\text{93}}$Nb($γ$,5n)$^{\text{88m,g}}$Nb were measured for the first time.

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