Using Probe for EPMA software in "demonstration mode" to teach EPMA

[John Donovan]

It is worth mentioning that one can simulate time dependent intensity (TDI) effects in Probe for EPMA for teaching microprobe techniques.  However, there are a few caveats:

1. First one needs to turn off the Penepma simulation mode for the TDI simulation using the checkbox as shown here:



Note also the "tooltip" pop up help that mentions this. The only downside of turning off the Penepma simulation is that wavescans will only contain a single peak for the specified emission line, but since the Penepma simulation can be turned off for (TDI) unknowns and/or standards and turned on for wavescans, this shouldn't be a problem.

2. So once the Penepma simulation is turned off and the TDI acquisition is turned on in the Special Options dialog, the first element in the acquisition will always utilize a "Na" type log-linear intensity decay, while the second element will always utilize a "Si" smaller log-linear increase in intensity as one would normally observe in an alkali glass specimen.

Therefore to simulate TDI effects when teaching EPMA please realize that these TDI effects will only be generated when Penepma simulations are turned off in the Acquisition Options dialog and "self" TDI acquisitions are selected in the Special Options dialog, both accessed from the Acquire! window.

Then you will be able to display simulated  TDI intensities as shown here for the first element "Na":



And perform quantitative analyses of these "beam sensitive" materials for teaching in simulation or demonstration mode:

Un    6 Obsidian CAMM 112, Results in Elemental Weight Percents

ELEM:       Na      Si      Ti      Al      Fe      Mg      Mn       P      Ca       K       H       O
TYPE:     ANAL    ANAL    SPEC    SPEC    SPEC    SPEC    SPEC    SPEC    SPEC    SPEC    SPEC    SPEC
BGDS:      LIN     LIN
TIME:    10.00   10.00     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---
BEAM:    30.01   30.01     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---

ELEM:       Na      Si      Ti      Al      Fe      Mg      Mn       P      Ca       K       H       O   SUM 
    34   3.044  33.456    .060   6.563    .909    .018    .015    .003    .322   3.761    .086  49.326  97.563
    35   2.837  33.586    .060   6.563    .909    .018    .015    .003    .322   3.761    .086  49.326  97.486
    36   3.127  33.961    .060   6.563    .909    .018    .015    .003    .322   3.761    .086  49.326  98.151
    37   3.151  33.766    .060   6.563    .909    .018    .015    .003    .322   3.761    .086  49.326  97.980

AVER:    3.040  33.692    .060   6.563    .909    .018    .015    .003    .322   3.761    .086  49.326  97.795
SDEV:     .143    .220    .000    .000    .000    .000    .000    .000    .000    .000    .000    .000    .322
SERR:     .071    .110    .000    .000    .000    .000    .000    .000    .000    .000    .000    .000
%RSD:     4.70     .65     .00     .00     .00     .00     .00     .00     .00     .00     .00     .00
STDS:      336      14     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---

STKF:    .0735   .4101     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---
STCT:    26.25  144.09     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---

UNKF:    .0165   .2764     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---
UNCT:     5.90   97.12     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---
UNBG:      .42     .86     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---

ZCOR:   1.8380  1.2188     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---
KRAW:    .2249   .6741     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---
PKBG:    15.05  114.76     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---

TDI%:   10.394  -2.482     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---
DEV%:      1.5      .2     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---
TDIF:  LOG-LIN LOG-LIN     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---
TDIT:    13.00   13.00     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---
TDII:     6.36    97.9     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---
TDIL:     1.85    4.58     ---     ---     ---     ---     ---     ---     ---     ---     ---     ---

[John Donovan]

And finally another "tweak" to improve the simulation mode in Probe for EPMA: we modified the background curvature model to produce background intensities (as a function of sin theta) for LDE/PC Bragg multi-layer crystals that more closely resemble what we actually observe on the actual instrument:



This allows one to model curved backgrounds more easily in simulation mode. Update PFE as usual to obtain this improved wavescan simulation for teaching and training off-line.

[John Donovan]

Just in case anyone didn't know, one can perform WDS simulations in Probe for EPMA using 30 keV beam energies. Basically we finally finished modeling all the elements up to 30 keV using 1 eV energy bins using Penepma.



To update your Penepma pure element databases, use the Help | Update button as described here:

https://smf.probesoftware.com/index.php?topic=202.msg9589#msg9589

Being sure to check the Update Penepma Monte-Carlo Files Only checkbox.

[Panseok]

Hi John,

I have a quick newbie question. The "Use Penepma for WDS simulation" option in Acquisition Options is currently grayed out. Is it only enabled in demo mode? If so, how do I activate it?

Many thanks,
Panseok

[John Donovan]

I have a quick newbie question. The "Use Penepma for WDS simulation" option in Acquisition Options is currently grayed out. Is it only enabled in demo mode? If so, how do I activate it?

Good question.   It's because your config files are set to connect to an actual instrument.

You'll want to install Probe for EPMA on an off-line computer for running simulations. My lab manager Julie Chouinard has all the students in her EPMA class install the software on their laptops and then uses it for teaching.  So she'll explain the theory of something, and then have the students collect data in simulation mode on their laptops.  Saves lots of time for actual measurements on the instrument.

Once you have Probe for EPMA (and CalcZAF) installed on an off-line computer, simply answer "Yes" to the question: "Do you want to interface to the instrument hardware?":

https://smf.probesoftware.com/index.php?topic=535.msg13237#msg13237

Then PFE will connect to a simulated microprobe for teaching and/or modeling. The "Use PENEPMA for WDS Simulation" option is checked by default, but does take a bit longer, so if you don't need precise modeling of secondary peaks, then you can leave it unchecked.

Of course one could edit the InterfaceType=0 in the Probewin.ini file on your actual probe computer, but then you better remember to set it back again!