Reaction 9Be(alpha, n gamma)12C is interesting for the nuclear theory, astrophysics etc. and can be used as the fast neutron source [1, 2]. In present work this reaction is regarded as the basis for the high temperature plasma alpha-particles diagnostic. Alpha-particles are playing key role in ensuring efficient plasma heating in DT fusion and important in many other regimes, so the study of its behavior is needed for the implementation and finding of optimal operation scenarios in large tokamaks. The line shape (LS) measurement and analysis of the Doppler broadened 4.44 MeV gamma line corresponded to the 2+ 12C level de-excitation allow to obtain spatial and velocity distribution functions (DF) of alpha- particles. Compared to other diagnostics, for example, based on atomic- and mass-spectroscopy methods, this technique gives the opportunity for the most direct DF parameters measurement, especially in the MeV energy range. Calculations of the LS require knowledge of the reaction kinematics. For the reaction study the dedicated series of experiments has been carried out using the Ioffe Institute Cyclotron alpha-particle beam in the energy range of Ea=1.9-6.5 MeV with 0.1-0.5 MeV step. LS measurements were performed with HP Ge detector placed at 0, 15, .. 150 degrees relative to the beam axis. The neutron and gamma angular distributions (AD) also have been measured [1]. Since level’s spin is not zero, kinematic and therefore LS calculation cannot be performed using information about only AD but angular correlation function (ACF) data is needed in this case. ACF can be represented in the form of the associated Legendre polynomial superposition with the coefficients (parameters) depending on Ea. Cyclotron measurements together with EXFOR cross-section [2] data were used to find ACF parameters energy dependence. For this purpose the Doppler Monte-Carlo (DMC) (which takes into account angular and energy resolution of the detectors, relativistic and other effects) as well as special parameter set limitation techniques were developed [3]. In September 2009 for the first time 4.44 MeV LS was measured with the HP Ge detector on JET. In these experiments the ion-cyclotron heating of the 4He plasma was used [4]. The reaction kinematic data, which were found in Ioffe Cyclotron experiments with described developed technique, were used to analyze LS measured on JET. In Maxwell approach particles temperature can be roughly estimated as about 150 keV, which is conform to expected value for given experiments. The simulation of the absolute count-rate turns to be in good agreement with the experiment. Suggested technique is under continuous improvement and planned to be used for other reaction and, in perspective, can be regarded as important instrument for gamma diagnostics on ITER.

1. Kiptilyi, V.G., Doinikov, D.N., Naidenov, V.O., et al.,Vopr. At. Nauki Tekh., Ser.: Fiz. Yad. Reaktorov. TIYaS. XI. Special Issue, 1997, p. 223.
2. R. Kunz at. al // Phys.