sPHENIX discussion of the superconducting solenoid

["Yip, Kin" <kinyip AT bnl.gov>]

Hi,

 

From the temperature change and my conversations with the Cryo group, I can see that late last night (9:30 pm or so), they’ve started to use 10+ K He

gas to cool the system back to <15 K or so.   This afternoon (around 2 pm-ish), they started to use the ~4 K He to cool.

 

Now, the outlet temperature is fluctuating around 7 K and whereas various thermometers in the magnet were showing around ~5 K or ~6 K.

Hopefully, soon it’ll be close to 4-5 K …. I understand that they’ll let the coils soaked in the bath of ~4.5 K He so that hopefully the temperature

deep inside the metallic coil will be all ~ 4.5K.   Sunday or so, they’ll open the valves for the “phase separator” and then there will be a circulating

loop (of liquid He) between the phase-separator and the magnet coil.   This is my rough/probably inaccurate understanding of what it’s going on

and what it’s going to happen.   Thanks for taking the risk to read up to here, hahaha …… J

 

Kin

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