Visit to the particle accelerator DESY in Hamburg

DESY stands for "Deutsches Elektronen Synchrotron", today these facilities are better known in common parlance as electron or particle colliders. Large electromagnets accelerate the particles until they collide and keep them on their trajectory over the entire length of the facility. In Hamburg, the largest linear accelerator is currently three kilometers long. It therefore does not run in a circle, but is straight. The electromagnets and the accelerating elements are cooled with liquid helium at four Kelvin (-269°C). The cavity resonators serving as accelerators must be cooled down this low to make them superconducting. The helium lines that therefore run everywhere secure LESER 441 XXL safety valves at DESY, for example.

If the vacuum that partially insulates the lines breaks, the helium can heat up abruptly and thus expand greatly. Very large safety valves are used, but they are not directly exposed to the cryogenic temperature. Particle accelerators, however, are not necessarily the most common facilities found anywhere. Where can you find these or similar conditions as well? Cryogenic helium cooling can be found in the following applications, for example:

  • Fusion reactors such as the Iter research reactor
  • Medical radiation therapy devices
  • Industrial radiography equipment for materials testing

Again, it should be noted in the design that many safety valves are required for very low temperatures by design but are still decoupled from the primary process. They then only have to discharge the cryogenic medium in the event of overpressure. This is why many Semi Nozzle 441 Safety Valves are used in the processes at DESY, although LESER recommends Full Nozzle safety valves and stellited discs and seats for permanent cryogenic use.