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Moderator: Ellery Frahm, [log in to unmask],
Electron Microprobe Lab, University of Minnesota

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*

Probe folks,

Today I received the following message from one of the professors in  
our department:

> Ellery,
>
> I was just at a meeting where a colleague was telling me about his  
> SX-100 microprobe and the amazing improved spatial resolution it  
> gets for both imaging and quantiative analyses owing to the LaB6  
> source. It's my understanding that JEOL sells the 8200 with an  
> option of a LaB6 or tungsten filament source.  Do you know if JEOL  
> will retrofit 8900s with Lab6 and if so, how much it costs?  The  
> fellow with the SX100 says that Cameca charges something like $10k  
> extra for a LaB6 source on the SX-100...
>
> Marc

Is such a refit possible or feasible?  I know it is easy to go from  
LaB6 to W filament, but it seems harder to go the other way.  I  
believe that we'd need an ion pump at the top of the column for LaB6,  
but would a turbo pump need necessary too or are diffusion pumps  
okay?  Are the electronics, heating system, etc. the same or not?

I am also curious if anyone is currently running or has recently run  
a LaB6-outfitted machine.  Are the concerns about beam stability  
valid, or is the issue overblown?  What is the typically stability in  
your experience?  What are current opinions about LaB6?  Having never  
used a LaB6-equipped microprobe, I don't have any first-hand  
experience or observations on which to draw.

Any facts, observations, opinions, wild speculations, or hearsay are  
welcome.

Best,
Ellery

--------------------
Ellery E. Frahm
Research Fellow & Manager
Electron Microprobe Laboratory
University of Minnesota - Twin Cities
Department of Geology & Geophysics
Lab Website: http://probelab.geo.umn.edu
Personal Website: http://umn.edu/~frah0010