Prompt gamma-rays in three H-rich moderators exposed to neutrons. (July 2021)

• Record Type: Journal Article
• Authors: Garcia-Reyna, Mayra Guadalupe; Vega-Carrillo, Hector Rene; Vazquez-Bañuelos, Joel; Torres-Cortes, Carina Oliva; Campillo-Rivera, Guillermo Eduardo; Marquez-Mata, Claudia Angelica
• Is Part Of: Progress in nuclear energy. Volume 137(2021)
• Publication Date: 2021-07
• Subjects: Prompt γ-rays -- Pulse-height spectrum -- 241AmBe -- Moderator -- NaI(Tl) -- Monte Carlo; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 333.7924
• DOI: 10.1016/j.pnucene.2021.103789
• Languages: English
• ISSNs: 0149-1970

Abstract

Abstract: Monte Carlo methods, with the MCNP5 code, were used to estimate the pulse-height spectra of γ-rays induced in three hydrogen-rich moderators modeled as 20.32 cm-diameter spheres made of water, polyethylene and gasoline. The source-term was a point-like 241 AmBe neutron source. The pulse-height spectra were estimated as measured with a NaI(Tl) scintillator and as measured by a detector without the low-resolution limitation. In the moderators the induced γ-rays are produced in 1 H(n, γ) 2 H reactions; also another two gamma rays are scarcely produced in 12 C(n, n'γ) 12 C and 16 O(n, n'γ) 16 O inelastic scattering reactions. For the case of polyethylene moderator the pulse-height spectrum was measured with a gamma-rays spectrometer with a 3" Ø × 3" NaI(Tl) scintillator and compared with the calculated spectrum, where is shown that the 4.44 MeV photon is produced by the neutron source. Highlights: The PHS of neutron-induced γ-rays were calculated using MC methods. Moderators are water, polyethylene and gasoline. The poor-resolution spectra show the 2.22 MeV due the 1 H(n, γ) 2 H reaction. The spectra show the induced γ-rays due to inelastic scattering in 12 C and 16 O. Experimental validation was carried out for polyethylene.