a chopper disc for a device for the processing of neutron beams is made of carbon fibers and has a concentric , hollow cylindrical recess for receiving a hub for connection to a pivot bearing . the chopper disc also includes a concentric absorber area for absorbing neutrons striking the chopper disc and at least one window in the absorber area through which neutrons of the neutron beam can pass . the carbon fibers extend from the outer periphery of the chopper disc radially in the direction of the recess and contact the recess tangentially .