sPHENIX discussion of the superconducting solenoid

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

Hi,

 

From the attached Cryo plot, you can see that the Magnet Coil has been cooled to below 150 K. Roberto told me that in principle, the pressure is already

low enough that they could try to switch today.  But they seem to want to switch tomorrow to use that 5K source.  So that it may cool down more quickly,

though still in controlled mode, from 140K to <100 K.  After that, they can forget about worrying about the controlled cool-down as the from 100K to ~4K,

the total contraction is <10% (and the temperature control of delta <= 40 K in controlled cool-down was to keep overall contraction <10%) and use

the 4K source to cool down the Magnet quickly to ~4.x K.   If the change from 140K to 100K happens quickly enough, they can try to go to 4.x K

(and the “return to plant” mode --- that we can run “forever”) this Friday.

 

Paul Giannotti today has been making the strain-gauge and linear-pot connection all day today without any technician’s help.   ( I provided a bit of moral

support and actually found the connector for the current source and the right manual … )    When I left Bldg. 912 shortly after 6:30 pm tonight, Paul was

still there making jumpers (and probably connecting the last 3 linear pots of Jon Hock’s--- he already did the 4 old Magnet linear pots and one Jon’s linear pot).

 

There were probably a few mistakes when he did the test (again and again) and Paul will work with Frank Toldo tomorrow to possibly figure them out.

 

Kin

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