The work of this thesis must be associated with the realization of EUROGAM detector. This device will be composed in a first time of 45 Germanium gamma radiation detectors (each being surrounded with 10 BGO detectors). The purpose of this thesis was the design and the miniaturization of the amplification line which must be associated with each Germanium detector (are also included the circuit of ballistic shortage correction). The design and study of amplifier has been effected with the help of computer-aided design in using SPICE software. The details are explained widely but in another part, the author studies the theoretical interpretation of disturbing phenomena.