A device is proposed for assembling chain components to a chain, wherein at least two chain components include radioactive radiation sources. The device includes a housing, a working channel which extends along a first axis of the housing, a loading unit connected to the working channel and having at least two receiving devices for chain component magazines, wherein at least one receiving device is configured to receive a radiation source magazine, as well as at least one means for ejecting the chain components received from the magazines, and an joining unit for joining chain components. The at least two receiving devices are positioned so that the magazines for chain components received therein are spaced along the first axis and positioned vertically above the working channel.