Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have visited many accelerator, and these blue things


can be seen where cryo technology is used. What are they (He valves?/safety valves?) Why is so many needed?


Here there are more blue things seen mounted on top of the helium line behind the LHC.

More blue things

share|cite|improve this question
My guess, and only a guess, they are arrays of klystrons. . "to produce high-power carrier waves for communications and the driving force for modern particle accelerators." see also – anna v May 21 '12 at 4:23
No not klystrons - there is no HV, or waveguides. It has something to do with cryo cooling. – Hans-Peter E. Kristiansen May 21 '12 at 4:31
If you read up, there are klystrons used for superconducting magnets."The superconducting section of the linac employs eighty one 6-cell cavities power by eighty one 550 kW, 805 MHz klystrons." They are a sort of power supply. – anna v May 21 '12 at 5:50
@anna v: Why would I need to read up-when I know what a klystron is!? -They are not a sort of power supply -read your own wiki link. The klystrons that drives the LCH are several meters high. – Hans-Peter E. Kristiansen May 21 '12 at 7:50
@annav, the cavities that are powered by klystrons is implying the accelerating force in the cavities is generated by the klystrons. The magnets themselves will not be powered by high power RF. – Kortuk May 21 '12 at 17:02

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.