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Production of the ${^{55-57}}$Co nuclei on ${^{\rm nat}}$Ni in photonuclear reactions using bremsstrahlung gamma photon irradiation with end-point energy $E_{\rm{\gamma max}}$ between 35 and 94~MeV has been studied. The experiment was performed at the electron linear accelerator LUE-40 NSC KIPT using the methods of $\gamma$ activation and off-line $\gamma$-ray spectroscopy. The obtained experimental flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ agree with the data found in literature. The theoretical flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{th}}$ for the production of ${^{55-57}}$Co and ${^{55-57}}$Ni were estimated using the cross-section values $\sigma(E)$ from the TALYS1.95 code and bremsstrahlung spectra of gamma photons calculated by GEANT4.9.2. The experimental results for ${^{56,57}}$Co agree with the cumulative $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{th}}$. However theoretical prediction fails to reproduce the measured cross-sections for the production of ${^{55}}$Co., Comment: 11 pages, 6 figures, 4 Tables

The photoproduction of the $^{\rm 93m}$Mo nucleus on natural molybdenum was studied using the electron beam of the LUE-40 linac RDC "Accelerator" NSC KIPT. Measurements were performed using the activation method and off-line $\gamma$-ray spectrometric technique. For the $^{\rm nat}$Mo($\gamma,x$n)$^{\rm 93m}$Mo reaction the experimental flux-averaged cross-section <$\sigma(E_{\rm \gamma max})$>$_\rm m$ at the bremsstrahlung end-point energy range of 38--93 MeV was first time determined. The theoretical values of the yields $Y_{\rm m,g}(E_{\rm \gamma max})$ and flux-averaged cross-sections <$\sigma(E_{\rm \gamma max})$>$_{\rm m,g}$ for the $^{\rm nat}$Mo($\gamma,x$n)$^{\rm 93m,g}$Mo reactions were calculated using the cross-sections $\sigma(E_{\rm \gamma})$ from the TALYS1.96 code for different gamma strength functions and level density models. The comparison showed strong discrepancies between the experimental values and the theoretical results of <$\sigma(E_{\rm \gamma max})$>$_m$., Comment: 8 pages, 9 figures, 2 tables. arXiv admin note: text overlap with arXiv:2308.02243, arXiv:2311.03038

Liquid metal batteries (LMBs) are a promising grid-scale storage device however, the scalability of this technology and its electrochemical performance is limited by mass transport overpotentials. In this work, a numerical model of a three-layer LMB was developed using a multi-region approach. An alternative design concept for the battery aimed at reducing mass transport overpotentials, increasing cell capacity, and improving electrochemical cell performance was implemented and evaluated. The design consisted of a coil implanted in the cathode, which induced mixing in the layer. Four cases were compared: three in a 241 Ah LMB at 0.3, 0.5 and 1 A/cm$^{2}$, and one in a larger 481 Ah LMB at 0.5 A/cm$^{2}$. LMB performance was determined by comparison against baseline diffusion cases and a change in molar fraction of 0.1. The modified LMB exhibited dramatic performance increases with a 78% and 85% reduction in mass-transport overpotentials at 0.3 A/cm$^{2}$ and 0.5 A/cm$^{2}$, respectively. The improved performance of the battery was directly attributed to the flow generated in the cathode. It was found that the coil substantially increased the poloidal volumetric average velocity. Periodically, vortices formed that removed concentration gradients from the cathode-electrolyte interface, minimising concentration polarisation. The viability of the design was tested in a lab-scale prototype using Galinstan as the working fluid. The velocity of the flow was determined using particle image velocimetry (PIV), and the results compared to the numerical model. There was a close match between the experimental and numerical results, validating the numerical model and the viability of the design. Implementation of this design concept in future LMBs could lead to the realisation of extended discharge capacities and improved voltages. Future work is planned to test the coil in a working battery.

The photoproduction of $^{95\rm m}$Nb on ${^{\rm nat}\rm{Mo}}$ was studied using the electron beam of the LUE-40 linac RDC "Accelerator" NSC KIPT. Measurements were performed using activation and off-line $\gamma$-ray spectrometric techniques. The experimental flux-averaged cross-section $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{m}}$ for the ${^{\rm nat}\rm{Mo}}(\gamma,x\rm np)^{95\rm m}$Nb reaction at the bremsstrahlung end-point energy range of 38--93 MeV has been first time obtained. The estimated values $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{g}}$ for the formation of $^{95}$Nb in the ground state and total cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{tot}}$ for the studied reaction were determined. The theoretical values of the yields $Y_{\rm m,g,tot}(E_{\rm{\gamma max}})$ and flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{m,g,tot}}$ for the ${^{\rm nat}\rm{Mo}}(\gamma,x\rm np)^{95\rm m,g,tot}$Nb reactions were calculated using the cross-sections $\sigma(E)$ from the TALYS1.95 code for six different level density models. The comparison showed a significant excess of the experimental results over the theoretical $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{m,g,tot}}$ values., Comment: arXiv admin note: substantial text overlap with arXiv:2308.02243

The results of the photoproduction of isomeric pairs from the ({\gamma},xn) and ({\gamma},pxn) reactions on nuclei from Zr up to Ta at the bremsstrahlung end-point energy range 30-100 MeV are systematized. Measurements were performed at the electron beam of the LUE-40 linac RDC "Accelerator" NSC KIPT using the activation method and off-line {\gamma}-ray spectrometric technique. The theoretical isomeric ratios IR for the nuclei-products of studied reactions were calculated using the cross-sections {\sigma}(E) from the TALYS1.95 code for six different level density models. The data from the international databases were additionally used to compare experimental results and theoretical predictions. The obtained results let us make conclusions about trends of values and energy dependence of IR in studied photonuclear reactions. Further directions of experimental research in the RDC "Accelerator" NSC KIPT are discussed., Comment: 10 pages, 13 figures, 1 table

The production of the $^{180\rm{m}}\rm{Hf}$ nuclei in the photoproton reaction ${^{181}\rm{Ta}}(\gamma,p)$ was studied at end-point bremsstrahlung energies $E_{\rm{\gamma max}}$ = 35-95 MeV. The experiment was performed at the electron linear accelerator LUE-40 NSC KIPT with the use of the $\gamma$ activation and off-line $\gamma$-ray spectroscopy. The experimental values of the bremsstrahlung flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{m}}$ for the ${^{181}\rm{Ta}}(\gamma,p)^{180\rm{m}}\rm{Hf}$ reaction were determined, and at $E_{\rm{\gamma max}} > 55$ MeV obtained for the first time. The measured values, also as the literature data, are significantly exceed the theoretical flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{th}}$. The $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{th}}$ values were calculated using the cross-section $\sigma(E)$ computed with the TALYS1.95 code for six different level density models. A comparative analysis of the calculated total cross-sections for the reactions ${^{181}\rm{Ta}}(\gamma,p)^{180}\rm{Hf}$ and ${^{181}\rm{Ta}}(\gamma,n)^{180}\rm{Ta}$ was performed. It was shown that the photoproton $(\gamma,p)$ to photoneutron $(\gamma,n)$ strength ratio is consistent with the estimates based on the isospin selection rules and the value from the $(e,e'p)$ experiment., Comment: 9 pages, 4 figures, 2 tables

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., Comment: 9 pages, 9 figures, 1 table

Motor brain-computer interface (BCI) development relies critically on neural time series decoding algorithms. Recent advances in deep learning architectures allow for automatic feature selection to approximate higher-order dependencies in data. This article presents the FingerFlex model - a convolutional encoder-decoder architecture adapted for finger movement regression on electrocorticographic (ECoG) brain data. State-of-the-art performance was achieved on a publicly available BCI competition IV dataset 4 with a correlation coefficient between true and predicted trajectories up to 0.74. The presented method provides the opportunity for developing fully-functional high-precision cortical motor brain-computer interfaces., Comment: 6 pages, 3 figures, 4 tables. Preprint. Under review

In experiments on the electron linac LUE-40 of RDC "Accelerator" NSC KIPT, the flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{exp}}$ of photonuclear reactions ${^{100}\rm{Mo}}(\gamma,n)^{99}\rm{Mo}$, ${^{27}\rm{Al}}(\gamma,x)^{24}\rm{Na}$, ${^{93}\rm{Nb}}(\gamma,n)^{92m}\rm{Nb}$, ${^{93}\rm{Nb}}(\gamma,3n)^{90}\rm{Nb}$, and ${^{181}\rm{Ta}}(\gamma,n)^{180g}\rm{Ta}$ were measured using the $\gamma$-activation technique. The theoretical flux-average cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{th}}$ were computed using the partial cross-section $\sigma(E)$ values from the TALYS1.9-1.95 codes and bremsstrahlung $\gamma$-flux calculated using GEANT4.9.2. Two different experimental setups were used in the experiments: an aluminum electron absorber and a deflecting magnet to clean the bremsstrahlung $\gamma$-flux from electrons. A comparison of the flux-average cross-sections measured for two experimental setups was performed. The possibility of using the reactions ${^{100}\rm{Mo}}(\gamma,n)^{99}\rm{Mo}$, ${^{27}\rm{Al}}(\gamma,x)^{24}\rm{Na}$, ${^{93}\rm{Nb}}(\gamma,n)^{92m}\rm{Nb}$, ${^{93}\rm{Nb}}(\gamma,3n)^{90}\rm{Nb}$, and ${^{181}\rm{Ta}}(\gamma,n)^{180g}\rm{Ta}$ as monitors of the bremsstrahlung $\gamma$-flux for the energy range 30-100 MeV was investigated., Comment: 8 pages, 6 figures, 1 table

The bremsstrahlung flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ for the photonuclear reactions ${^{65}\rm{Cu}}(\gamma,n)^{64}\rm{Cu}$, ${^{63}\rm{Cu}}(\gamma,n)^{62}\rm{Cu}$, ${^{63}\rm{Cu}}(\gamma,2n)^{61}\rm{Cu}$ and ${^{63}\rm{Cu}}(\gamma,3n)^{60}\rm{Cu}$ have been measured in the range of bremsstrahlung end-point energies $E_{\rm{\gamma max}}$ = 35-94 MeV. The experiments were performed with the electron beam from the NSC KIPT linear accelerator LUE-40 with the use of the activation and off-line $\gamma$-ray spectrometric technique. The calculation of the flux-average cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{th}}$ was carried out using the cross-section $\sigma(E)$ values from the TALYS1.95 code with the default options. It is shown that the experimental average cross-sections for the reactions ${^{65}\rm{Cu}}(\gamma,n)^{64}\rm{Cu}$, ${^{63}\rm{Cu}}(\gamma,n)^{62}\rm{Cu}$, ${^{63}\rm{Cu}}(\gamma,2n)^{61}\rm{Cu}$ are systematically higher than the theoretical estimates in the TALYS1.95 code. The obtained $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ supplement the data of different laboratories for the case of reactions $(\gamma,n)$ and $(\gamma,2n)$. For the reaction ${^{63}\rm{Cu}}(\gamma,3n)^{60}\rm{Cu}$, the values of $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ were measured for the first time., Comment: 9 pages, 10 figures, 1 table. arXiv admin note: text overlap with arXiv:2111.13904, arXiv:2203.11249

The bremsstrahlung of accelerated electrons passing through a converter is used to study multiparticle photo-nuclear reactions. The results of calculations, numerical modeling, design, and testing of a special magnetic cleaning system to obtain a "pure" beam of bremsstrahlung quanta when studying the cross-sections of such reactions at the LUE-40 linac are presented. The system is based on commercially available permanent magnets of rectangular cross-sections. The maximum on-axis field is 0.9 T, which provides sufficient separation of the electron beam and gamma rays at a distance of more than 90 mm from the magnet., Comment: 9 pages, 8 figures

The total bremsstrahlung flux-averaged cross-sections <$\sigma$(E$_{{\gamma}max}$)> for the photonuclear reactions $^{nat}$Ni($\gamma$,xn)$^{57}$Ni and $^{nat}$Ni($\gamma$,xn)$^{56}$Ni have been measured in the range of end-point energies E$_{{\gamma}max}$ = 35...94 MeV. The experiments were performed with the beam from the NSC KIPT electron linear accelerator LUE-40 with the use of the activation and off-line $\gamma$-ray spectrometric technique. The calculation of the flux-average cross-sections <$\sigma$(E$_{{\gamma}max}$)>$_{th}$ was carried out using the partial cross-section values $\sigma$(E) computed with the TALYS1.95 code and bremsstrahlung $\gamma$-flux calculated by GEANT4.9.2. The experimental results are compared with theoretical calculations and data from the literature. The obtained <$\sigma$(E$_{{\gamma}max}$)> values expand the energy range of previously known experimental data., Comment: 6 pages, 5 figures, 4 tables. arXiv admin note: substantial text overlap with arXiv:2111.13904

The total bremsstrahlung flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ for the photonuclear reactions $^{181}\rm{Ta}(\gamma,\textit{x}n; \textit{x} \leq 8)^{181-\textit{x}}\rm{Ta}$ have been measured in the range of end-point energies $E_{\rm \gamma max}$ up to 95 MeV. The experiments were performed with the beam from the NSC KIPT electron linear accelerator LUE-40 with the use of the activation and off-line $\gamma$-ray spectrometric technique. The calculation of average cross-sections was carried out using the cross-section values computed with the TALYS1.95 code for different level density models $LD$ 1-6. A comparison between the experimental total cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ and the theoretical values has shown satisfactory agreement for the $^{181}\rm{Ta}(\gamma,\textit{x}n)$ reactions with the escape of 1-4, 6 and 7 neutrons. The closest agreement with the measured data is observed with the $LD$5 computation version, which represents the microscopic level density model taking into account Hilaire's combinatorial tables., Comment: 12 pages, 5 figures, 4 tables. arXiv admin note: text overlap with arXiv:2108.01635

The photoneutron reaction $^{181}\rm{Ta}(\gamma,3n)^{178m,g}\rm{Ta}$ was investigated with the beam from the NSC KIPT electron linear accelerator LUE-40. The measurements were performed using the residual $\gamma$-activity method. The bremsstrahlung flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$, $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{m}}$, $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{g}}$ and the isomeric ratio of the reaction products $d(E_{\rm{\gamma max}})$ have been measured. Theoretical values of averaged cross-sections and isomeric ratio were calculated using partial cross-sections from the TALYS1.95 code for different level density models $LD$ 1-6. The obtained experimental $d(E_{\rm{\gamma max}})$ agree with the literature data, but differ from the theoretical values in absolute magnitude and the behavior of the energy dependence. A comparison of the found averaged cross-sections with the calculated ones showed the best agreement for the case of the $LD$ 5 model., Comment: arXiv admin note: text overlap with arXiv:2103.09859

Experiments to determine the yields and bremsstrahlung flux-averaged cross-sections <${\sigma}(E_{{\gamma}max})$> of photonuclear reactions on the natural Mo targets were performed on the beam from the NSC KIPT electron linear accelerator LUE-40 with the use of the ${\gamma}$-activation technique. The bremsstrahlung end-point energies were in the range $E_{{\gamma}max}$ = 35...80 MeV. The bremsstrahlung quantum flux was calculated with the program GEANT4.9.2 and, in addition, was monitored using the $^{100}$Mo$({\gamma},n)^{99}$Mo reaction. Calculations of the yields and average cross-sections <${\sigma}(E_{{\gamma}max})$> for photonuclear reactions on stable Mo isotopes were computed using the ${\sigma}(E)$ cross-sections from the TALYS1.95 code (for the level density model LD1). A comparison of experimental and calculated cross-sections <${\sigma}(E_{{\gamma}max})$> for reactions $^{92}$Mo$({\gamma},2n)^{90}$Mo and $^{92}$Mo$({\gamma},pn)^{90}$Nb was performed., Comment: 6 pages, 8 figures, 2 tables

The bremsstrahlung flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ and the cross-sections per equivalent photon $\langle{\sigma(E_{\rm{\gamma max}})_{\rm{Q}}}\rangle$ were first measured for the photonuclear multichannel reaction ${^{27}\!\rm{Al}}(\gamma,\textit{x})^{22}\rm{Na}$ 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 $\gamma$-activation technique. The bremsstrahlung quantum flux was calculated with the program GEANT4.9.2 and, in addition, was monitored by means of the $^{100}\rm{Mo}(\gamma,n)^{99}\rm{Mo}$ reaction. The flux-averaged cross-sections were calculated using the partial cross-section $\sigma(E)$ values computed with the TALYS1.95 code for different level density models. Consideration is given to special features of calculating the cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ and $\langle{\sigma(E_{\rm{\gamma max}})_{\rm{Q}}}\rangle$ for the case of the final nucleus $^{22}\rm{Na}$ production in the $^{27}\!\rm{Al}$ photodisintegration reaction via several partial channels $\textit{x}$: $\rm{n}\alpha + dt + npt + 2n{^{3}\rm{He}} + n2d + 2npd + 2p3n$., Comment: 8 pages, 9 figures, 1 table, 19 references. arXiv admin note: text overlap with arXiv:2012.14475

The bremsstrahlung flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ for the $^{181}\rm{Ta}(\gamma,\textit{x}n; \textit{x} = 1 \div 8)^{181-\textit{x}}\rm{Ta}$ 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 $\gamma$-activity method. The theoretical $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ values were computed using the cross-sections $\sigma(E)$ from TALYS1.9 code. A comparison between the measured cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ and the theoretical values has demostrated their good agreement for the reactions with escape of up to 6 neutrons, and substantial differences for the $(\gamma,7\rm{n})$ and $(\gamma,8\rm{n})$ reactions. Isomeric ratios of the average cross-sections $d(E_{\rm{\gamma max}})$ have been found for the $^{181}\rm{Ta}(\gamma,3n)^{178g,m}\rm{Ta}$ reaction products. The results have been compared with the literature data and the computations based on TALYS1.9 code., Comment: 9 pages, 5 figures, 1 Table

The bremsstrahlung flux-averaged cross sections for the photoneutron reactions $^{\text{93}}$Nb($\gamma $,xn;x=1-5)$^{\text{(93-x)m,g}}$Nb were measured in the range of boundary energies of bremsstrahlung $\gamma $-quanta $E_{\gamma \text{max}}$=33-93 MeV with a step $\Delta E_{\gamma \text{max}}\approx $ 2 MeV. The isomeric ratios of the average cross-sections of the products of the reactions $^{\text{93}}$Nb ($\gamma $ ,4n)$^{\text{89m,g}}$Nb and $^{\text{93}}$Nb($\gamma $,5n)$^{\text{88m,g}}$ Nb were determined in the energy ranges $E_{\gamma \text{max}}$ = 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 ($\gamma $,2n) and ($\gamma $,4n) are in good agreement with theory, while in the case of reactions ($\gamma $,n), ($\gamma $,3n), and ($ \gamma $,5n), some discrepancies are observed. The results obtained for the reactions ($\gamma $,n), ($\gamma $,3n) and ($\gamma $,4n) are in satisfactory agreement with the known literature data. The average cross sections for the reactions ($\gamma $,2n) and ($\gamma $,5n) and the isomeric ratios of the reaction products $^{\text{93}}$Nb($\gamma $,5n)$^{\text{88m,g}}$Nb were measured for the first time.