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Description
The RF linac for the ELI - Gamma Beam Source (ELI-GBS) is being installed in Bucharest-Magurele (Romania). TW accelerating structures and SLED cavities are powered by klystrons via waveguide network that includes directional couplers for power monitoring and feedback. Before RF conditioning can begin, the linac must be properly tuned in terms of the RF phase and frequency.
The waveguide system was reviewed with respect to its electrical length to ensure correct RF phase tuning. This work was carried out after installation but prior to connecting the waveguides to the accelerating structures. Fine RF-phase adjustments will be achieved through mechanical deformation of the waveguides. Since each klystron feeds four structures, the waveguides must be tuned so that the RF phase at the entrance of each structure matches its longitudinal position in the accelerator.
Considering the fact that only 5-degree deviation in phase can be compensated by mechanical deformation of waveguides, larger discrepancies must be corrected physically by bending existing waveguide components to correct position or even reposition accelerator segments. Therefore precise analysis of the waveguide network was performed using a network vector analyzer. This paper reports the results of phase measurements performed on the assembled waveguide system. In addition, directional couplers were individually tested with VNA to verify their performance before integrating them into the system.
Funding Agency
This work was carried out in part under the contract PN 23 21 01 06 sponsored by the Romanian Ministry of Research, Innovation and Digitalization
| Paper status | Proceeding files received |
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