The flux-weighted average cross-sections of \({}^{\mathrm {nat}}{\mathrm {Dy}}(\upgamma , {\mathrm {xn}}){}^{{159,157,155}}{\mathrm {Dy}}\) reactions were measured at the bremsstrahlung end-point energies of 12, 14, 16, 65 and 75 MeV with the activation and off-line \(\upgamma \)-ray spectrometric technique using the 20 MeV Electron Linac for beams with high Brilliance and low Emittance (ELBE) at Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany and the 100 MeV electron linac at the Pohang Accelerator Laboratory, Korea. The \({}^{\mathrm {nat}}{\mathrm {Dy}}(\upgamma , {\mathrm {xn}}){}^{{157,155}}{\mathrm {Dy}}\) reaction cross-sections as a function of photon energy were also calculated theoretically using TALYS 1.9 code. Then the flux-weighted average values at different end-point energies were obtained based on the theoretical values of mono-energetic photons. These values were compared with the flux-weighted values of present work and are found to be in general agreement. It was also found that the experimental and theoretical formation cross sections of \({}^{159}{\mathrm {Dy}}\), \({}^{157}{\mathrm {Dy}}\) and \({}^{155}{\mathrm {Dy}}\) from the \({}^{\mathrm {nat}}{\mathrm {Dy}}(\upgamma , {\mathrm {xn}})\) reactions increased from their respective threshold values to a certain energy where other reaction channels opened. After reaching a maximum value, the individual reaction cross-sections slowly decreased with the increase of the bremsstrahlung energy due to the initiation of other competing reactions at higher energy, which indicates the impact of the excitation energy. However, the production cross sections of \({}^{157}{\mathrm {Dy}}\) and \({}^{155}{\mathrm {Dy}}\) from the \({}^{\mathrm {nat}}{\mathrm {Dy}}(\upgamma , {\mathrm {xn}})\) reactions slightly increase in between and then decreased slowly with bremsstrahlung energy, which is due to the contributing reactions of higher mass isotopes.

\（{} ^ {\ mathrm {nat}} {\ mathrm {Dy}}（\ upgamma，{\ mathrm {xn}}）{} ^ {{159,157,155}} {\的通量加权平均横截面使用激活和离线\（\ upgamma \）射线光谱技术，使用20 MeV电子在at致辐射终点能量为12、14、16、65和75 MeV的条件下测量mathrm {Dy}}位于德国德累斯顿的Helmholtz-Zentrum Dresden-Rossendorf的高亮度和低发射率光束（ELBE）的直线加速器，以及韩国浦项加速器实验室的100 MeV电子直线加速器。的\（{} ^ {\ mathrm {NAT}} {\ mathrm {镝}}（\ upgamma，{\ mathrm {XN}}）{} ^ {{157155} {} \ {mathrm镝}} \）理论上也使用TALYS 1.9代码计算了反应截面随光子能量的变化。然后，根据单能光子的理论值，获得了不同端点能量下的通量加权平均值。将这些值与当前工作的通量加权值进行比较，发现总体上是一致的。还发现\（{} ^ {159} {\ mathrm {Dy}} \），\（{} ^ {157} {\ mathrm {Dy}} \\）和\ （{} ^ {155} {\ mathrm {Dy}} \）来自\（{} ^ {\ mathrm {nat}} {\ mathrm {Dy}}（\ upgamma，{\ mathrm {xn}}）\ ）反应从各自的阈值增加到其他反应通道打开的特定能量。达到最大值后，由于在较高能量下引发了其他竞争反应，因此随着reaction致辐射能量的增加，各个反应截面逐渐减小，这表明了激发能的影响。但是，\（{} ^ {157} {\ mathrm {Dy}} \）和\（{} ^ {155} {\ mathrm {Dy}} \\）的生产横截面来自\（{} ^ { \ mathrm {nat}} {\ mathrm {Dy}}（\ upgamma，{\ mathrm {xn}}）\）之间的反应随着致辐射能量的增加而略有降低，然后缓慢降低，这是由于更高质量的贡献反应同位素。