Measurement of the 13C(n,γ) thermal cross section via neutron irradiation and AMS

Ampoules of amorphous 99.5% enriched 13 C were irradiated at the PF1b neutron beam line at the high-flux ILL research reactor in order to produce 14 C atoms. The precise ratio of 14 C/ 13 C was subsequently measured at the VERA Accelerator Mass Spectrometer, allowing the 13 C(n, γ γ ) 14 C thermal cross section to be accurately determined. This is the first measurement of this cross section at sub-eV energies via this technique and the result of 1.52 ± 0.07 1.52±0.07 mb for the thermal cross section is in good agreement with other recent measurements which were performed via Prompt Gamma-ray Activation Analysis.