Measurements of an ion beam diameter extracted into air through a large-bore metal capillary

To extract an ion beam into air, the technique using a single macro-capillary has been paid attention. We have expanded the bore of the metal capillary up to 500 μm∅ inlet diameter to increase the beam intensity and have measured the intensity distributions of the extracted 3 MeV proton beam. Furthermore, we have tilted the capillary angle and measured the intensity distributions of the ion beam. In this article, we will present the experimental results together with the simulation which takes the tilt angles of the capillary into account.