Many thanks Karel for compiling this - a very useful discussion.
We historically had an Ultrashield 300 on a Fourier 300, and a "red" valve
(Z58140, as per the discussions with others at the time). We DIY'd the rest
of the helium manifold because the magnet was so small that it was barely
economic enough to pay to attach the system to the recovery system alone. The
dynamic range of the Fourier electronics was always kind of poor so it was
hard to see any helium valve-related artefacts if they were there or not.
We've decommissioned this a few months ago, and replaced it with a "new"
Ultrashield 400 on our older AVIII console, and just carried over the helium
manifold from the 300 magnet because it fitted and why not. This is a "new"
magnet to me, and some observations with a very wet DMSO-d6 sample showing
lots of noise and ugliness around the base of the water peak have got me
suspecting that yes, maybe the red valve is to blame for this.
Other than the interesting magnet boil-off data presented by Brian, does
anyone have any NMR experimental data for red Z58140 versus any of the silver
valves?
Also, does anyone know what the Bruker screw-thread fittings are? Is it a
standard or a Bruker "special"? I was thinking to temporarily swap it with
one of the silver valves off of our solids Ascent 400WB systems (they won't
notice 😊) so I could convince myself the cost of a new silver
valve would be worth it, but then I'd need the opposite adaptor to the one
Bruker provide (Z52523) i.e. KF25 to screwthread. Our Physics cryo-centric
mechanical workshop didn't recognise but maybe someone else knows better?
Thanks
Geoff
-----Original Message-----
> From: main_at_ammrl.groups.io <main_at_ammrl.groups.io> On Behalf Of Karel Klika
>Sent: Sunday, February 25, 2024 7:27 PM
> To: main_at_ammrl.groups.io
> Subject: [External] [AMMRL] helium check valves
Dear all,
Many thanks to all who responded (Peter Dormer, Thomas Smith, Shing (Simon)
Sham, Geoffrey Akien, George Sukenick, Bob Berno, David Vander Velde, Brian
Cherry, John Decatur, Hasan Celik, Mike Lumsden, David Jones, and Margaret
Eastman), nothing unfortunately that resolved the pulsecal or BCU questions
but plenty on the helium check valve question. Thanks for the information
and pics that I have collated in the accompanying document.
There seems to be no problem with using the new check valves and also leaving
them in place when doing a helium refill (but caution is advised and also
consultation with Bruker). Only questions are what parts to get for what you
want to hook up and the part numbers. Currently we are not collecting the
helium so we only needed to decide if we wanted to:
1. Join both exit ports up and then attach the check valve. You can buy the
whole manifold apparatus from Bruker (P/N Z54230: SET HE MANIFOLD D2XX which
includes check valve Z52395 but not the adaptor Z52523: ADAPTER KF25 HE
MANIFOLD D2XX, very unclear exactly what is included and what is not), quite
expensive though, or make the manifold attachments yourself and just buy
the valve (Geoffrey Akien has done this).
2. Keep the old check valve on one exit port and put a new check valve on the
other exit port.
3. Put a new check valve on each exit port.
I think we will probably go for the third option.
Kind regards and thanks to all again for your input, Karel Klika
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Received on Mon Mar 04 2024 - 06:44:10 MST