Cryogenics
The magnet system assembly weights 1300 tonnes and is cooled by liquid
helium at 4.8 kelvin (-268 °C). It takes some 30 days to cool down to
this temperature.
The approximate cryogenic cooling power requirement is 2.3 kilowatt at
4.5 kelvin and an additional 11.5 kilowatt at 60 to 80 kelvin.
The cooling power is generated by two main systems:
- 6.5 kilowatt helium liquefier
- 60 kilowatt helium refrigerator
The liquefier produces liquid helium at a temperature of around 4.5 kelvin
while the refrigerator produces gas helium at a temperature around 60 to 80
kelvin. The liquid and gas helium are then send to the so called proximity
cryogenics system which controls the temperature of the magnets. For the
cooling of the toroid magnets, two liquid helium pumps with a capacity of
1.2 kg/s each are included in the proximity cryogenics system.
The energy of 1600 megajoule stored in the magnet system is equivalent
to the kinetic energy of the whole 1300 tonnes magnet system at a speed
of 180 km/h.
Presentation Toroid PCS
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General
Technical