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| Figure 1. Transparent model of a 7-gap resonator. One can see the six lambda/4 oscillators mounted to a half shell, which carry the drift tubes |
| Homepage and schedule | Motivation | Charge breeding system | Linear accelerator | Target and Miniball | Collaboration |
The three 7-gap resonators are similar to those built for the high-current injector at the MPI für Kernphysik in Heidelberg [1]. A 7-gap resonator is a compromise between total energy gain per resonator and high transit time factor. The REX-ISOLDE special types of split ring resonators are designed and optimized for synchronous particle velocities of βs = 5.4%, 6.0% and 6.6% assuming a realistic total resonator voltage of about 1.75 MV at 90 kW in-coupled power. The resonator has a single resonance structure, which consists of a copper half shell and three arms attached to both sides of the shell [2]. Each arm consists of two hollow profiles, surrounding the drift tubes and carrying the cooling water.
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| Figure 1. Transparent model of a 7-gap resonator. One can see the six lambda/4 oscillators mounted to a half shell, which carry the drift tubes |
The output of the IH-structure is matched with a triplet lens to the first 7-gap resonator. Between first and second resonator there is an additional doublet for transverse focusing. Detailed beam dynamics calculations have been performed, showing normalized acceptances of 1.2 π mm mrad for the x,x'-plane and 3 π mm mrad for the y,y'-plane and nearly 100% transmission. The phase and energy spread of the injected ions have been assumed to ± 10° and ± 1.3% respectively.
The development and construction of the three 7-gap-resonators was done by the MPI für Kernphysik in Heidelberg.
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Energies Ein = 1.1-1.2 MeV/u, Eout = 0.8-2.2 MeV/u Total resonator voltage Vrod = 1.8 MV (A/q = 4.5) Peak power consumption Wpeak = 80 kW (A/q = 4.5) Shunt impedance R = 64, 66 and 67 MΩ/m (A/q = 4.5) Longitudinal energy spread ΔW/W = ± 0.5 % |