Spot-welding solid targets for high current cyclotron irradiation.

Zirconium-89 finds broad application for use in positron emission tomography. Its cyclotron production has been limited by the heat transfer from yttrium targets at high beam currents. A spot welding technique allows a three-fold increase in beam current, without affecting 89Zr quality. An yttrium foil, welded to a jet-cooled tantalum support base accommodates a 50µA proton beam degraded to 14MeV. The resulting activity yield of 48±4 MBq/(μA∙hr) now extends the outreach of 89Zr for a broader distribution.