  This Thesis present the process of development very low sensitivity to
background radiation n-g scintillation detectors with close to 100% efficiency
to corpuscular diagnostic of thermonuclear plasma. The detectors developed
using this methodology were installed in two major Neutral Particle Analyzers
for the JET tokamak (Gemma-2M and ISEP) and they operated successfully for many
years. The configuration for such detectors is based on the growing of very
thin scintillators of CsI(Tl) on top of quartz supporters and then glued to
photomultipliers by keeping the thickness of the supporter and the entrance
window of the photocamera of the photomultiplier very thin low sensitivity to
background radiation can be achieved.
