Browsing by Author "Nchodu, M R"

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    Alpha emission from the interactions of 14-200 MeV neutrons on carbon-12
    (1994) Nchodu, M R; Brooks, F D
    Cross-sections for the production of alpha particles from the ¹²C(n,α)⁹Begs and ¹²C(n,n')3α reactions were measured for incident neutrons in the energy range 25 to 52 MeV. The measurements were reduced to absolute cross-sections by simultaneously observing deuteron recoils from n-d elastic scattering in the scintillator using D(n,n)D elastic scattering cross-section as a reference standard. Neutron energy was determined by time-of-flight and pulse shape discrimination (PSD) was used to identify and separate alphas and deuterons from other reaction products. The feasibility of distinguishing different mechanisms for the ¹²C(n,n')3α reaction by means of PSD was also investigated.
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    Open Access
    Determination of energy spectra of proton therapy beams
    (2002) Nchodu, M R; Brooks, F D; Buffler, Andy; Jones, Dan T L
    A technique has been developed for measuring the energy spectra of high-energy proton therapy beams in situ under conditions similar to those used for radiotherapy at the South African National Accelerator Centre. The method is based on proton elastic scattering, H(p,p)H, in a thin polyethylene radiator and uses two ΔE-E detector telescopes to detect coincident proton pairs. Measurements have been made to investigate the effect of standard beam modification elements on the energy spectra of proton therapy beams produced by a passive scattering system. Monte Carlo simulations of the spectra were computed with the MCNPX 2.1.5 Monte Carlo code to compare with experimental measurements.