[AMMRL] helium plumbing on vintage Bruker magnets

From: Vander Velde, David via groups.io <david.vandervelde02=gmail.com_at_groups.io>
Date: Tue, 27 Jan 2026 13:11:16 -0700

Hi, I am now involved in managing a Bruker Ultrashield magnet (which I had
previously done decades ago) after a period of managing Ascend magnets.
Prior to the Ultrashield series, every magnet I worked with (Oxford or
Spectrospin) had a cross piece connecting however many helium stacks there
were, with a small one way valve on the single vent.. The Ultrashields came
without this piece, with just Tygon tubing connecting the stacks to a
similar one way valve. With the Ascend series, the cross piece came back,
with a much more robust one way valve which can stay in place during helium
fills. (pictures attached)

I took care of Ultrashields for quite a while without understanding why the
cross piece went away, or what the really optimal way was to vent the cold
gas released during a helium fill. The two stacks on the mid field magnets
behave very differently--the one with the fill port and the helium sensor
appeared to be wide open to exiting helium, whereas the other stack was
extensively set up with baffles or other internal structures which impeded
the helium.

I have a very strong preference for filling magnets that feature the cross
piece, where how much helium is exiting through which stack is transparent
to me.

My questions are, has anyone modified their UltraShield with the Ascend
style cross piece? Alternatively, does anyone know of reasons why that
would be a bad idea?

--
Dave VanderVelde


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Received on Tue Jan 27 2026 - 12:30:12 MST