Following on from the installation of four solid state amplifiers (SSAs) in the booster in 2012, the first two out of three 150 kW SSAs for the storage ring were delivered by ELTA and installed in cell 23 in June and September 2013, respectively (see Figure 164). They have passed the site acceptance tests and were connected to the first two HOM-damped cavities, which had been installed in August in the middle of the 7 m straight section of cell 23. Since October 2013, these two cavities have been in operation in USM and provide 0.5 MV accelerating voltage each. The third HOM-damped cavity was installed in cell 23 during the winter shutdown (Figure 165). The last SSA was delivered and had its preliminary site acceptance test with a dummy load in December. From January 2014 it will power the third cavity.

Three new HOM-damped cavities

Fig. 164: Three new HOM-damped cavities (undergoing vacuum conditioning) in the 7 m straight section of cell 23.

Three 150 kW SSAs powering the HOM-damped cavities

Fig. 165: Three 150 kW SSAs powering the HOM-damped cavities in cell 23.

An important milestone has also been achieved with the in-house development of SSAs using cavity combiners. In July, the first 10 kW prototype combining 18 RF modules was successfully tested. It delivered as much as 12 kW with a global efficiency above 62%. The next step will be to manufacture and connect 114 further RF modules to the cavity combiner in order to reach the design goal of 75 kW with 132 connected RF modules.