Figure-8 Storage Ring - Ion Beam Injection into a Closed, Magnetic System

To store high current low-energetic ion beams of up to 10 A, a superconducting storage ring (F8SR) based on solenoidal and toroidal magnetic guiding fields is investigated at Frankfurt University. Besides simulations, a scaled down experimental setup with normalconducting magnets was built. Investigations of beam injection into closed, magnetic guiding fields are in progress. Therefore, a new kind of injection system consisting of a solenoidal injection coil and a special vacuum vessel was constructed. It is used to inject a hydrogen beam from the side between two toroidal magnets. In parallel operation, a second hydrogen beam is transported through both magnets to represent the circulating beam. The current status of the experimental setup and first experimental results will be shown. F8SR – FIGURE-8 STORAGE RING Figure 1: F8SR – Low-Energy Superconducting Magnetostatic Storage Ring. The F8SR is a low-energy superconducting magnetostatic storage ring for high current beams. For example it is possible to transport two proton beams of up to 10 A with an energy of up to 150 keV, one in each direction. In order to manage the high current beams, toroidal magnets (called toroids) and solenoids are used around the whole ring for continuous beam focusing. The twisted Figure-8 geometry is ∗ niebuhr@iap.uni-frankfurt.de necessary to compensate the RxB drift which causes an up or down drift of beams transported through toroidal magnetic fields. If two beams are transported independently – one in each direction – interaction experiments can be performed at two areas of the ring where the beams cross naturally. One possible design of the F8SR is shown in Fig. 1. THE INJECTION EXPERIMENT To investigate the beam dynamics of such a storage ring experimentally a scaled down experiment with two 30 degrees toroids with a magnetic field of up to 0.6 T is used. Investigations regarding the beam transport through toroidal magnetic fields were done before [1]. At the moment the experiment is being reconstructed to investigate the beam injection between the two toroids. Therefor an injection system with a new injection coil was designed and manufactured. The final layout of the complete injection experiment is shown in Fig. 2. Although the injection experiment is still under construction, the biggest and most important part of the experiment – the injection system – is built in and the vacuum tests were successful. The injection system consists of a heightadjustable vacuum tank system and the solenoidal injection magnet. Besides the injection system the two injectors, the two filter channels [2], the two toroids, the end tank and the whole periphery (power supplies, high voltage terminals, etc.) are ready for use. Only the xy-flange is still in production. The xy-flange is used to change the injection position of the injection beam into the solenoidal injection coil. The simulations show that this is necessary [3]. The entire possible offset of the flange is 100 mm in each radial direction. The assembly of the experiment will be finished in summer 2017. In Fig. 3 a photo of the current status of the experiment is shown.