4.5 Kelvin lower cryogenic cold box arrives at FRIB

As civil construction on the FRIB Project advances ahead of schedule, the progress is allowing more technical installations to take place.

On 27 October, the 4.5 Kelvin lower cryogenic cold box was delivered to FRIB from Oklahoma. Weighing in at 100,000 pounds, the 39-foot-wide cold box was placed horizontally in FRIB’s cold box room. It joins the vertical upper cryogenic cold box, also weighing 100,000 pounds, that was delivered to FRIB on 10 August. The two cold boxes will be connected to cool helium to an extremely low temperature, which will make the cavities within the cryomodules superconducting in FRIB’s linear accelerator tunnel.

The upper cold box lowers the temperature of the helium from 300 degrees kelvin (K) to 60 K. The lower cold box serves as the second step in the helium-cooling process, dropping the temperature from 60 K to 4.5 K.

When the cavities are superconducting, there is no resistance, which means there will be virtually no heat loss with an electrical current, making FRIB more energy-efficient as it accelerates rare isotope beams. 

The FRIB baseline schedule calls for both coldboxes to be installed by October 2017; it now looks possible to have the installation done earlier and to make liquid helium in 2017.