In October, FRIB staff installed all 24 cryomodules (CMs) in the linear accelerator’s (linac) second segment (LS2). All of the LS2 cryomodules were cooled to 2 kelvin (K) in November.

The linac is made of cryomodules that contain superconducting radio frequency (SRF) cavities and superconducting solenoid magnets. Operating at cryogenic temperatures 2 degrees above absolute zero, the SRF cavities accelerate the beam and the solenoids steer and focus it.

Operating the cryomodules at 2 K increases the energy efficiency of the accelerator.

All twelve β=0.29 half-wave resonator (HWR) CMs placed along LS2 have been cooled to 2 K. Nine of them had superconducting radio-frequency (SRF) cavities energized to their full field of 2 tesla.

All twelve β=0.53 HWR CMs are also placed along LS2. Seven of them have been cooled to 2 K.

FRIB staff fully energized and tested both the cavities and the superconducting solenoidal magnets inside the cryomodules.

The energizing took place in the testing area prior to moving the cryomodules to their final location in the tunnel. The cryomodules are energized and tested again once installed in the tunnel prior to beam operations.

Cryomodule production is ramping down, as 41 of 46 cryomodules have been installed in the linac tunnel as of November. All but three have been tested.