Design and test of an innovative static thin target for intense ion beams

In the present work an innovative design for thin target suited for high intensity beam is proposed, which consists in the deposition of the target material on a substrate of pyrolytic graphite, whose in-plane thermal conductivity allows a quick dissipation into a heat sink. Such a target cooling system has been designed for the NUMEN experiment (hosted at LNS-INFN, Catania), which will use targets of particular isotopes under highly intense ion beams. The time evolution and the spatial distribution of the temperature have been numerically calculated. Results of these calculations show that the target/graphite system can tolerate ion beams with intensities of about 50 eμA and energy of 15 MeV/u. A significant nonuniformity in the target thickness would limit the energy resolution of the reaction products. A technique, based on the α-particle transmission, is used for measuring the thickness and uniformity of the target. Preliminary results from tests with this technique applied to the graphite substrate are shown.