1. Method for analysing an object ( 24 ) by neutron interrogation, by the associated particle technique, wherein a device ( 26 ) is used which includes a sealed-tube neutron generator ( 3 ) equipped with an alpha-particle detector ( 8 ) and at least one gamma radiation detector ( 10 ), where the alpha particle detector allows the neutrons emitted by the generator in a given solid angle to be monitored by detecting alpha particles associated with the neutrons emitted, where the gamma radiation detector allows gamma radiation emitted by the object ( 24 ) to be detected when the object is placed in the given solid angle and receives the emitted neutrons, and the device ( 26 ) is placed in a given position (P 1 ) relative to the object, where the latter is placed in the given solid angle, where the method includes steps which involve: sending neutrons from the generator towards the object ( 24 ), carrying out acquisition of the data which is then provided by the alpha particle detector and gamma radiation detector, and processing the data thus acquired in order to obtain a three-dimensional mapping (d 1 ) of the object. where this method is characterised in that at least one displacement of the device ( 26 ) is made around the object ( 24 ), in order to place the device in another given position (P 2 , P 3 , P 4 ) in relation to the object, where the latter is kept fixed in the given solid angle, the steps are repeated, each three-dimensional mapping (d 1 , d 2 ) is geometrically corrected in order to allow this three-dimensional mapping to be updated relative to the set of all the three-dimensional mappings, and the three-dimensional mappings are combined with each other in order to obtain a single three-dimensional mapping (d 3 ).