Tokamak Fusion Test Reactor charge exchange atom spectrometry using a natural diamond detector

Natural diamond detectors (NDD) developed in Russia were used for fast char ge exchange H-0 atom spectrometry and flux dynamic measurements during Toka mak Fusion Test Reactor (TFTR) H+ minority ion cyclotron resonance heating (ICRH) experiments in deuterium plasma. For selected NDDs, the high energy resolution (similar to 2%-3%) and radiation resistance (5 X 10(14) n/cm(2)) and low sensitivity to neutrons and gammas enable spectrometry of fast (0. 2-3 MeV) atoms in TFTR radiation conditions. The NDD compact housing (simil ar to 2 cm(+3)) allowed noninterfering insertion into the particle charge e xchange flight tube giving both systems similar views which allows comparis on of their spectra and fluxes. A small NDD was chosen to limit count rates to 7 X 10(5) s(-1). A spectroscopy amplifier operating with pileup inspect ion at such rates was developed, enabling measurement of the dependence of fast perpendicular proton energy spectra on ICRH heating power during sawto oth-free and sawtooth-crash times. The results agree with a model developed for sawtooth redistribution of fast particles. (C) 1999 American Institute of Physics. [S0034-6748(99)53901-4].