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September 2007

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Subject:
From:
Michael Cheatham <[log in to unmask]>
Reply To:
JEOL-Focused Probe Users List <[log in to unmask]>
Date:
Tue, 4 Sep 2007 09:34:14 -0400
Content-Type:
text/plain
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JEOL Probe Users Listserver

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*

Hi,
    Thanks to all who offered input on this 'loss of counts' problem.  In
working with Chuck Herrington (Geler) on Friday, I finally stumbled onto the
problem.  It required one of those 'quiet times' when no one was around
outside the lab for me to realize that the noise that I had occasionally
been hearing was not coming from the hallway, but was in fact coming from
WDS 5!  Long-story-short is that the P10 hoses had come loose in their
bracket on the side of the detector carriage.  They had rotated out and away
from the carriage.  At crystal/detector positions down towards the sample
the P10 lines were rubbing/pinching between the end cap on the detector and
the tank wall where it narrows at its interface with the column.  What would
then happen was that the detector would be OK (positioned properly with
respect to the crystal in one direction but would be independently rotated
out of position when moving in the other direction.
    I opened up the tank on Friday afternoon, found the problem,
repositioned the P10 lines, tightened up the brackets, and now everything is
working the way it should.

Cheers
Mike



On 8/30/07 8:20 AM, "Michael Cheatham" <[log in to unmask]> wrote:

> JEOL Probe Users Listserver
> 
> Moderator: Ellery Frahm, [log in to unmask],
> Electron Microprobe Lab, University of Minnesota
> 
> Post a message: send your message to [log in to unmask]
> 
> Unsubscribe: send "SIGNOFF PROBEUSERS" to [log in to unmask]
> 
> On-line help and FAQ: http://probelab.geo.umn.edu/listserver.html
> 
> 
> 
> *
> 
> Hi,
>     I have a problem that I need help in figuring out.  First, instrument
> parameters:
> JEOL JXA 8600: 5 WDS's, EDS, CL, SEI, BEI
> WDS 1: GFPC: TAP, PET, LDE1, LDEC
> WDS 2: Xe: LIF, PET
> WDS 3: Xe: LIF, PET
> WDS 4: Xe: LIF, PET
> WDS 5: GFPC: TAP, LDEB
> 
> 20 kV, 10 nA, 10 um spot
> Astimex 53 mineral Std grain mount
> Astimex 44 Metal Std mount
> 
> Element Table: 
> Na  TAP WDS5
> Mg  TAP WDS5
> Al  TAP WDS5
> Si  TAP WDS5
> K   PET WDS2
> Ca  PET WDS2
> Ti  LIF WDS4
> Fe  LIF WDS4
> Cs  PET WDS3
> 
> Geller Software: dSpec, dQuant, dPict, etc
> 
> 
> A grad student is doing feldspar analyses.  We are not using WDS1 right now
> because it needs optimization and it is on the 'to-do' list.  Student is
> trying to get a handle on accuracy and precision.  Using Astimex std
> PlagAn65 and measuring it as an unknown.  PHA's on the elements in the table
> are optimized, all elements calibrated.  Everything 'appears' to be normal.
> 
> Problem:  
> Analysis 1: Totals are good (97-99%) Individual concentrations are good.
> Analysis 2: Totals are bad (21%) Individuals are OK except Si and Al - way
> off!
> Analysis 3: Totals are good (97-99%) Individual concentrations are good.
> Analysis 4: Totals are bad (21%) Individuals are OK except Si and Al - way
> off!
> Analysis 5: Totals are good (97-99%) Individual concentrations are good.
> Analysis 6: Totals are bad (21%) Individuals are OK except Si and Al - way
> off!
> 
> On the 'bad' analyses, the reported conctration on Al and Si are consistent
> across the three runs.  It simply looks like the instrument can't find the
> peak.  I can't find anything wrong.
> 
> Have any of you ever seen anything like this before?
> 
> TIA
> Mike
> ********************************************************************
> Michael M. Cheatham
> 312 Heroy Geology Laboratory                Phone (315)-443-1261
> Syracuse University                         Fax   (315)-443-3363
> Syracuse, NY 13244-1070
> 
> email:[log in to unmask]
> http://earthsciences.syr.edu
> 
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> ********************************************************************

********************************************************************
Michael M. Cheatham
312 Heroy Geology Laboratory                Phone (315)-443-1261
Syracuse University                         Fax   (315)-443-3363
Syracuse, NY 13244-1070

email:[log in to unmask]
http://earthsciences.syr.edu

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