Cross section measurements for neutron inelastic scattering and the $(n, 2n\gamma )$ reaction on ${}^{206}\mathrm{Pb}$

Excitation functions for $\gamma$ production associated with the neutron inelastic scattering and the $(n, 2n)$ reactions on ${}^{206}\mathrm{Pb}$ were measured from threshold up to 18 MeV for about 40 transitions. Two independent measurements were performed using different samples and acquisition systems to check consistency of the results. The neutron flux was determined with a ${}^{235}\mathrm{U}$ fission chamber and a procedure that were validated against a fluence standard. For incident energy higher than the threshold for the first excited level and up to 3.5 MeV, estimates are provided for the total inelastic and level cross sections by combining the present $\gamma$ production cross sections with the level and decay data of ${}^{206}\mathrm{Pb}$ reported in the literature. The uncertainty common to all incident energies is 3.0% allowing overall uncertainties from 3.3% to 30% depending on transition and neutron energy. The present data agree well with earlier work, but significantly expand the experimental database while comparisons with model calculations using the talys reaction code show good agreement over the full energy range.

Figure 1

$\gamma$-ray spectrum recorded with a HPGe detector and with the ${}^{\mathrm{radiogenic}}\mathrm{Pb}$ sample. The spectrum was integrated over neutron energies lower than $\approx 25$ MeV. The main $\gamma$-ray peaks from the inelastic scattering on ${}^{206}\mathrm{Pb}$ are clearly visible.

Figure 2

Differential $\gamma$ production cross section for the 803.1-keV transition in ${}^{206}\mathrm{Pb}$ at ${110}^{\circ }$ and ${150}^{\circ }$ together with the ratio between the differential cross section values. The present data were smoothed with an averaging moving window filter for an easier comparison.

Figure 3

Full resolution $\gamma$ production cross section for the 803.1-keV transition in ${}^{206}\mathrm{Pb}$. (a) Differential $\gamma$ production cross section at ${110}^{\circ }$ and ${150}^{\circ }$. (b) Integral $\gamma$ production cross section compared with talys calculation.

Figure 4

Integral $\gamma$ production cross section for the 803.1-keV transition in ${}^{206}\mathrm{Pb}$. The upper panel represents the corresponding total uncertainty.

Figure 5

Differential $\gamma$ production cross section for the 537.5-keV transition in ${}^{206}\mathrm{Pb}$ at ${110}^{\circ }$ and ${150}^{\circ }$ together with the ratio between the differential cross section values. The data were smoothed with an averaging moving window filter for an easier comparison.

Figure 6

Integral $\gamma$ production cross section for the 537.5-keV transition in ${}^{206}\mathrm{Pb}$ from threshold to $E_n=18$ MeV together with a zoom from the threshold up to 1.7 MeV, where the resonance structure is still visible.

Figure 7

Integral $\gamma$ production cross section for the transitions from higher lying levels in ${}^{206}\mathrm{Pb}$ - 1/3.

Figure 8

Integral $\gamma$ production cross section for the transitions from higher lying levels in ${}^{206}\mathrm{Pb}$ - 2/3.

Figure 9

Integral $\gamma$ production cross section for the transitions from higher lying levels in ${}^{206}\mathrm{Pb}$ - 3/3.

Figure 10

$\gamma$ spectrum with the ${}^{\mathrm{radiogenic}}\mathrm{Pb}$ sample integrated over neutron energies above 8.12 MeV up to about 25 MeV. The 260.5-, 573.9-, 703.4- and 987.7-keV peaks from the ${}^{206}\mathrm{Pb}(n, 2n){}^{205}\mathrm{Pb}$ reaction are visible.

Figure 11

Integral production cross section for the $\gamma$ rays from the ${}^{206}\mathrm{Pb}(n, 2n\gamma ){}^{205}\mathrm{Pb}$ reaction.

Figure 12

Total neutron inelastic cross section of ${}^{206}\mathrm{Pb}$ on full energy range up to 18 MeV. The upper panel represents the corresponding total uncertainty.

Figure 13

Full resolution total inelastic cross section compared with the neutron total cross section measured at the Oak Ridge Electron Linear Accelerator [68] with a transmission setup.

Figure 14

The cross section of the 803.1-keV level in ${}^{206}\mathrm{Pb}$ together with the corresponding total uncertainty.

Figure 15

Cross section of excited levels above 1.3 MeV in ${}^{206}\mathrm{Pb}$ compared to previous experimental results and to talys calculations using default and microscopic parameters.