Gamma-ray measurements of 10B(α,pγ)13C reaction for alpha-particle diagnostics in fusion plasmas

Abstract

In the Joint European Torus with Be/W first wall, measurement of the confined fusion α-particles was based on detection of γ-rays due to the ⁹Be(α,nγ)¹²C nuclear reaction. The same diagnostic approach was accepted in the former design of the International Thermonuclear Experimental Reactor with a Be-wall. However, in the present non-beryllium design with full W wall and divertor, the boron impurity could be in plasmas due to boronisation of the vessel. In this case, the ¹⁰B(α,pγ)¹³C reaction is proposed for the α-particle diagnostics. Aiming to apply this approach in fusion devises with boron impurity, the results of in-beam studies of this reaction are presented. Excitation functions of the first three states of ¹³C were derived from the measured γ-ray angular distributions in the α-particle energy range 1.25 – 4.2 MeV. Also, high energy resolution γ-ray spectra were exploited to infer the proton differential cross-sections using the Doppler γ-line shape analysis. The results obtained are compared with other available data. Application of the ¹⁰B(α,pγ)¹³C reaction for diagnosing both energetic ⁴He-ions and fusion-born α-particles is proposed.