Modifications to the cooling system of Hall D solenoid
2015/09/02 - 2018/03/05
The page outlines the recent findings concerning the cooling system
of the Hall D solenoid and describes the proposed modifications.
- Finding
At the end of August 2015 Steve St.Lorant, looking at our documentation
concerning the magnet quenches, noticed that the cooling system
of the coils implemented at JLab is significantly different
from the original system implemented at SLAC, namely it
does not employ the thermosyphon effect, as the SLAC system did.
See the Steve's Note.
- Brief description
There are 2 pipes of 3/8-inch ID (more accurately, ID=0.46 inch)
going down through the chimney of each coil,
outside of the Helium vessel into the bottom of the vessel. At SLAC,
one was connected to the JT valve and used for the cooldown.
The other was connected to the bottom of the Helium can at
the top of the magnet (the "cold box") and provided a thermosyphon.
At JLab, both pipes are connected to the JT valve and used
for the cooldown.
- How to modify the JLab system?
Obviously, we should modify our system to get closer to the SLAC
design. Technically, it would be very difficult to connect the
pipe to the bottom of the Helium can. The plan is to insert
it into the 2-inch pipe which connects the top of the coil
with the bottom of the can. The chimney opening provides the access to
the pipes. See a sketch.
- Detailed desciption by George Biallas
Proposed modifications
pptx or
pdf.
Photos of the chimneys
pptx or
pdf.
Additional sketch
pdf.
- Calculations:
Evaluation of the flow through the syphon by Eugene Chudakov:
html.
- Schedule:
Preliminary work schedule by Tom Carstens:
pdf.
- Summary and outcome:
The modifications have been implemented by the end
of 2015. The magnet has run successfully in 2016, 2017, and up
to the current moment (5-Mar-2018) at the nominal 1350 A.
