  The next generation of radioactive ion beam facilities, which will give
experimental access to many exotic nuclei, are presently being developed. These
facilities will make it possible to study very short lived exotic nuclei with
extreme values of isospin far from the line of beta stability. Such nuclei will
be produced with very low cross sections and to study them, new detector arrays
are being developed. At the SPIRAL facility in GANIL a neutron detector array,
the Neutron Wall, is located. In this work the Neutron Wall has been
characterized regarding neutron detection efficiency and discrimination between
neutrons and gamma rays. The possibility to increase the efficiency by
increasing the high voltage of the photomultiplier tubes has also been studied.
For SPIRAL2 a neutron detector array, NEDA, is being developed. NEDA will
operate in a high gamma-ray background environment which puts a high demand on
the quality of discrimination between neutrons and gamma rays. To increase the
quality of the discrimination methods pulse-shape discrimination techniques
utilizing digital electronics have been developed and evaluated regarding bit
resolution and sampling frequency of the ADC. The conclusion is that an ADC
with a bit resolution of 12 bits and a sampling frequency of 100 MS/s is
adequate for pulse-shape discrimination of neutrons and gamma rays for a
neutron energy range of 0.3-12 MeV.
