Doppler broadening of gamma ray lines and fast ion distribution in JET plasmas

The Doppler broadening of individual gamma-ray lines was measured with a high purity germanium detector in JET plasma experiments. High-resolution gamma-ray spectrometry of nuclear reactions between energetic D, (3)He and (4)He ions accelerated by ion cyclotron resonance heating and main plasma impurities such as carbon and beryllium has been used. The nuclear reactions giving rise to gamma-rays have been identified and an effective temperature of the heated ions has been obtained in JET discharges. This technique could be used for fast ion and fusion alpha-particle studies in ITER.