Abstract: The first of a plurality of dynodes in a photomultiplier tube is made of a weldable nickel-beryllium alloy having a beryllium oxide layer thereon, formed into a desired shape from spot-welded segments. The dynode itself is then spot-welded to a support element. In one aspect of the invention, this first dynode has a scoop form. It is followed by a second dynode of spherical shape, made of a copper-beryllium alloy. A flap made of nickel-beryllium is juxtaposed to intercept photoelectrons that otherwise may escape photomultiplication in either the first or second dynodes. Additional venetian-blind type dynodes are employed to obtain the required photomultiplication.