A radiofrequency quadrupole (RFQ) for accumulation and cooling of heavy radionuclides at the SHIPTRAP facility at GSI

The SHIPTRAP facility at GSI will deliver cooled and purified ion bunches of heavy radionuclides produced at SHIP. A key element is the RFQ buncher. A buncher consists of four segmented rods to which rf voltages are applied to create a transversely focusing field. An electric DC field along the axis controls the longitudinal energy of the ions. The RFQ is filled with gas so that the energy of the ions entering into the linear trap will be reduced due to collisions with the gas and they will be confined at the end of the system. The ions can be extracted in a pulsed mode in bunches with high phase space density and can be delivered to a high vacuum region.