A beam shaper (10) for a neutron capture therapy. The neutron capture therapy comprises an accelerating tube (12) for accelerating a proton beam. The beam shaper (10) comprises a beam inlet (11), a target material (13) disposed in the accelerating tube (12), a retarder (14) adjoining to the target material (13), a reflector (15) surrounding the retarder (14), a thermal neutron absorber (16) adjoining to the retarder (14), and a radiation shied (17) and a beam outlet (18) disposed within the beam shaper (10). The beam shaper (10) is further provided with a cooling apparatus (20). The cooling apparatus (20) comprises a first cooling portion (21) for cooling the target material (13), and a second cooling portion (22) and a third cooling portion (23) extending respectively in a direction parallel to an axial direction of the accelerating tube (12) and in communication with the first cooling portion (21). The first cooling portion (21) is in plane contact with the target material (13). The second cooling portion (22) inputs a cooling medium into the first cooling portion (21), and the third cooling portion (23) outputs the cooling medium in the first cooling portion (21). The beam shaper (10) of the present invention cools a target material (13) by a cooling apparatus (20) disposed therein, and thus is simple in structure and easy to assemble.La présente invention concerne un formeur de faisceau (10) pour une thérapie par capture de neutrons. La thérapie par capture de neutrons comprend un tube d'accélération (12) pour accélérer un faisceau de protons. Le formeur de faisceau (10) comprend une entrée de faisceau (11), un matériau cible (13) disposé dans le tube d'accélération (12), un retardateur (14) adjacent au matériau cible (13), un réflecteur (15) entourant le retardateur (14), un absorbeur de neutron thermique (16) adjacent au retardateur (14), et un blindage contre le rayonnement (17) et une sortie de faisceau (18) disposés dans le formeur de faisceau (10). Le form
