NSS Configuration for EPMA instruments

[Probeman]

Something that has always bothered me, but doesn't really matter since I perform all quant calculations for EDS from Probe for EPMA, but the takeoff angle displayed in the NSS software is *not* 40 degrees as seen here:



instead it appears to be calculated from a number of different parameters in the Service | Instrument Configuration tab as seen here:



Question: does anyone out there know what these parameters should be to get 40 degrees takeoff for the Cameca and/or JEOL EPMA instruments.  I know it should be 40 and the Cameca working distance is 9.85 mm (according to John Fournelle), but what about the other fields?

[Probeman]

Ok, for whatever reason, this configuration seems to produce the correct take-off angle for EDS acquisition in the Thermo NSS software:



Now, when I acquire an EDS spectra I get this:



So, maybe the working distance really is 7 mm on the Cameca EPMA?

[Probeman]

It is *very* important to have the "Measure beam current Before EDS acquisition" checkbox *unchecked* in NSS as seen here:



if one is acquiring WDS data with Probe for EPMA because you will either get this error:



or even worse, the WDS measurement gets interrupted by the faraday cup insertion so the beam current drift correction will be completely wrong!

However, the timeout error will be avoided in future releases as Thermo has a new version of the TEPortal.dll that increases the EDS start function timeout from 2 to 10 seconds which they will distribute soon.

[Probeman]

Ok, for whatever reason, this configuration seems to produce the correct take-off angle for EDS acquisition in the Thermo NSS software:



Now, when I acquire an EDS spectra I get this:



So, maybe the working distance really is 7 mm on the Cameca EPMA?

OK, I'm confused again!   

About a year ago I updated to Thermo Pathfinder and now, using the same above detector parameters I'm seeing a takeoff angle (TA) of 31.41 degrees.  Is Pathfinder calculating the takeoff angle differently than NSS?

Again since we usually quant EDS spectra in Probe for EPMA, and only use Pathfinder for getting the net intensities of these specified peaks, this really doesn't matter all that much, but it's mystery and I'd like some help figuring it out.

Does anyone know what's going on here? What geometric parameters are necessary to obtain a 40 degrees take off angle for a Cameca instrument?
john

[Probeman]

Ok, for whatever reason, this configuration seems to produce the correct take-off angle for EDS acquisition in the Thermo NSS software:



Now, when I acquire an EDS spectra I get this:



So, maybe the working distance really is 7 mm on the Cameca EPMA?

OK, I'm confused again!   

About a year ago I updated to Thermo Pathfinder and now, using the same above detector parameters I'm seeing a takeoff angle (TA) of 31.41 degrees.  Is Pathfinder calculating the takeoff angle differently than NSS?

Again since we usually quant EDS spectra in Probe for EPMA, and only use Pathfinder for getting the net intensities of these specified peaks, this really doesn't matter all that much, but it's mystery and I'd like some help figuring it out.

Does anyone know what's going on here? What geometric parameters are necessary to obtain a 40 degrees take off angle for a Cameca instrument?
john

OK, so I really don't understand how Thermo calculates the takeoff angle, but Steve Seddio sent me this info for their new Pathfinder software and on a Cameca instrument (at least), this seems to work:



When these values shown above are specified, the inclination angle specifies the correct (40 degrees) takeoff angle.

[Probeman]

And just in case anyone else is interested, these are the EDS detector geometry parameters for our FEI Quanta 200 ESEM:



This results in a 35 degrees takeoff angle, when the stage tilt is zero.

[Probeman]

I recently installed Pathfinder v. 2.12 on an off-line computer for reprocessing EDS (and WDS) data in probe for EPMA and I note that Thermo seems to have altered things slightly as described in this previous post:

https://smf.probesoftware.com/index.php?topic=389.msg2134#msg2134

So besides the edits to the Probewin.ini file as described here:

https://smf.probesoftware.com/index.php?topic=1575.msg12156#msg12156

the main thing seems to be just editing the IP address keyword in the NSSMachineSettings.ini file (in the ProgramData\Thermo Scientific\NSS folder as shown here:

[Hardware_Communications]
IPAddress=127.0.0.1

You might also want to edit the detector parameters as described here (for Cameca instruments) if you want to run simulations:

https://smf.probesoftware.com/index.php?topic=136.msg8795#msg8795

It doesn't really matter though because Pathfinder always shows the same spectrum in simulation mode...

[dawncruth]

Has anyone had their faraday cup insert after EDS but still during WDS acquisition? I see this note could explain why, but I'm not using NSS, but Pathfinder 2.12

It is *very* important to have the "Measure beam current Before EDS acquisition" checkbox *unchecked* in NSS as seen here:



if one is acquiring WDS data with Probe for EPMA because you will either get this error:



or even worse, the WDS measurement gets interrupted by the faraday cup insertion so the beam current drift correction will be completely wrong!

However, the timeout error will be avoided in future releases as Thermo has a new version of the TEPortal.dll that increases the EDS start function timeout from 2 to 10 seconds which they will distribute soon.

[Probeman]

Both NSS and Pathfinder have the same issue.

For preventing NSS or Pathfinder from inserting the Faraday cup when the EDS acquisition finishes you have to turn off control of the Faraday cup in the Thermo AutomationClient app.  Or you could just always ensure that the WDS finishes after the EDS...

It's a similar problem with the JEOL EDS, but at least the JEOL software has a checkbox you can click:

https://smf.probesoftware.com/index.php?topic=868.msg13087#msg13087

It thinks it's being helpful to insert the Faraday cup after the EDS acquisition completes, but of course it's not helpful if the WDS acquisition is still running!

I should also mention to always be sure that you are not using the "automatic" time constant mode for quant work.