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 Zr-89 quality. An yttrium foil, welded to a jet-cooled tantalum support base accommodates a 50 A proton beam degraded to 14 MeV. The resulting activity yield of 48 4 MBq/(mu A.hr) now extends the outreach of Zr-89 for a broader distribution.