AbstractA natural silicon target was investigated in a $^{\text {nat}}$natSi($\mathbf {γ },γ ^{\prime }$γ,γ′) photon-scattering experiment with fully linearly-polarised, quasi-monochromatic $\mathbf {γ }$γ rays in the entrance channel. The mean photon energies used were $〈 {E}_{γ }〉 =$⟨Eγ⟩= 9.33, 9.77, 10.17, 10.55, 10.93, and 11.37 MeV, and the relative energy spread (full width at half maximum) of the incident beam was $\varDelta E_{γ }/〈 {E}_{γ }〉 ≈ $ΔEγ/⟨Eγ⟩≈ 3.5–4 %. The observed angular distributions for the ground-state decay allow firm spin and parity assignments for several levels of the stable even-even silicon isotopes.