Author Topic: NSS Configuration for EPMA instruments  (Read 3720 times)

Probeman

  • Emeritus
  • *****
  • Posts: 1955
  • Never sleeps...
    • John Donovan
NSS Configuration for EPMA instruments
« on: December 30, 2013, 12:20:57 pm »
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?
« Last Edit: December 30, 2013, 02:03:19 pm by Probeman »
The only stupid question is the one not asked!

Probeman

  • Emeritus
  • *****
  • Posts: 1955
  • Never sleeps...
    • John Donovan
Re: NSS Configuration for EPMA instruments
« Reply #1 on: December 30, 2013, 02:02:36 pm »
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?
The only stupid question is the one not asked!

Probeman

  • Emeritus
  • *****
  • Posts: 1955
  • Never sleeps...
    • John Donovan
Re: NSS Configuration for EPMA Acquisition
« Reply #2 on: December 19, 2014, 10:17:11 am »
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.
« Last Edit: December 19, 2014, 03:48:15 pm by John Donovan »
The only stupid question is the one not asked!

Probeman

  • Emeritus
  • *****
  • Posts: 1955
  • Never sleeps...
    • John Donovan
Re: Pathfinder vs. NSS Takeoff angle geometry
« Reply #3 on: June 10, 2019, 01:11:02 pm »
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
« Last Edit: June 10, 2019, 03:07:15 pm by Probeman »
The only stupid question is the one not asked!

Probeman

  • Emeritus
  • *****
  • Posts: 1955
  • Never sleeps...
    • John Donovan
Re: Pathfinder vs. NSS Takeoff angle geometry
« Reply #4 on: October 22, 2019, 11:50:50 am »
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.
The only stupid question is the one not asked!

Probeman

  • Emeritus
  • *****
  • Posts: 1955
  • Never sleeps...
    • John Donovan
Re: NSS Configuration for EPMA instruments
« Reply #5 on: October 22, 2019, 03:49:20 pm »
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.
The only stupid question is the one not asked!