Measurement of the Photonuclear (γ,n) Reaction Cross Section for 129I Using Bremsstrahlung Photons

• Published in: Nuclear science and engineering 2008-11, Vol.160 (3), p.363-369
• Main Authors: Rahman, Abul Kalam Md. Lutfor, Kuwabara, Shigeyuki, Kato, Kunio, Arima, Hidehiko, Shigyo, Nobuhiro, Ishibashi, Kenji, Hori, Jun-ichi, Nakajima, Ken, Goto, Tetsuo, Uematsu, Mikio
• Format: Article
• Language: English
• ISSN: 0029-5639; 1943-748X
• DOI: 10.13182/NSE160-363

Nuclear waste contains a significant amount of long-lived non-gamma-emitting nuclei such as 129 I and 14 C. A method of nondestructive detection for monitoring long-lived waste products is proposed as an application of the (γ,n) reaction. This method is useful for surveying long-lived "difficult-to-measure" nuclides, e.g., 129 I. Iodine-128 produced from the reaction of 129 I(γ,n) 128 I emits gamma rays that can easily be measured by a gamma-ray counter. We measured the inclusive photonuclear 129 I(γ,n) 128 I reaction cross section induced by bremsstrahlung photons. The photons were produced at a Ta target bombarded by 30-MeV electrons from a linear accelerator. The intensity of the slow neutrons was considered in the reactions of 127 I(n, γ) 128 I and 129 I(n, γ) 130 I. The activity of 128 I was measured by a high-purity germanium spectrometer. The gamma-ray flux and the neutron flux were calculated using the EGS and MCNP codes, respectively. The average activation cross section of the 129 I(γ,n) 128 I reaction had a 12% deviation from the evaluated International Atomic Energy Agency photonuclear data.