[Esr-users] Physics Division Cryo Coordination

[Rolf Ent]

Dear all, 

As many/most of you are already aware, we have asked Dave Kashy to act as Cryogenic 
Coordinator for the Physics Division. 

The simultaneous operation of Halls A, B and C with additional superconducting magnets 
is driving the End Station Refrigerator (ESR) at or above its capacity. This is actually better 
than originally projected - going into the 12-GeV project we had concern to operate Halls 
A, B and C simultaneously and keep all magnets cold unless the proposed ESR-II became 
available. It turned out that the CHLs can provide additional flow to the ESR, but we remain 
on the edge. 

Several other factors become limiting and the whole system somewhat unstable unless the 
conditions and demands across the entire eco-system are tightly tracked and regulated: 
CHL, CHL to ESR transfer lines, ESR and, Halls A, B and C. Hall D is not included here 
because its operation is independent of the ESR. 

We want to accomplish the most physics we can in every running period. This means 
running Halls A, B, C and D simultaneously if possible at all, and avoiding situations in 
which one of the halls causes disturbances on the other halls (or starves them), prioritizing 
recovery if there are cryo "crashes" and responding quickly to events that may cause 
larger problems if not deal with (e.g. a sudden shutdown of the CHL-ESR transfer line). 
In addition, we can benefit from as much coherence, consistency and understanding of 
the various cryogenic monitors and signals as we can achieve. 

For all the above reasons, we have asked Dave Kashy to be the cryo coordinator for the 
division. He will be the contact point between cryo and physics. His responsibilities are to 
start understanding, coordinate, balance and prioritize the cryo needs of all halls as well as 
look into ways/changes to make the cryo eco-system of the division more efficient and reliable. 
It is clear we can not count on an ESR-II in the near future yet. 

I would like to ask you to please provide all the support possible to Dave so that we all can 
make progress on the main reason we are there: to support our large user community to do 
exciting nuclear physics research. 

Best regards, 

Rolf 

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