Hi Geoff,
Thanks for the advice; the BBFO probe is around 2010, so there is a chance
it's an air flow issue. We've currently got the VT gas set to 400 lph, and
we don't spin on this system, but since the VT regulation is pretty minimal,
I'll drop the air down to 300 lph to see what happens. I'm still betting
that Mike's suggestion that the sensor at the bottom of the BST is dirty,
but I'm all for testing your hypothesis!
Best,
Walt
-------------------------------
Walter Massefski, Ph.D.
Director
Department of Chemistry Instrumentation Facility
Massachusetts Institute of Technology
77 Mass. Ave. Rm: 18-0090
Cambridge, MA 02139
T: (617) 253-2016
wwm_at_mit.edu
> On Jul 14, 2023, at 12:20 PM, Akien, Geoffrey via groups.io <g.akien=lancaster.ac.uk_at_groups.io> wrote:
>
> Hi Walt,
>
> How old is your RT probe? If its a pre-2010 (ish) probe with the old-style
> ball-type connector then it'll be what Bruker calls the "Flow-Turn" type
> (described in the VT manual), which doesn't have a bypass for the VT gas,
> and so doesn't tolerate as high flow VT gas flow rates. On my 2008-vintage
> RT BBFO you can just about get away with 535 lph, but adding spinning on top
> of that pushes it over the edge and starts to lift the sample up and triggers
> the emergency eject message. 400 lph is the standard flow rate at RT for
> this particular probe. IIRC cryoprobes generally (definitely He, not so sure
> about N2) use a higher gas flow rate so perhaps you've just transferred
> over this from the old parameters?
>
> Thanks
>
> Geoff
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Received on Fri Jul 14 2023 - 12:51:59 MST