Charles,

?This is a classic example of what I have been trying to get across with respect to thermion, calibrations and interpretation

You’re not exactly sure what you are looking at here because you’re using an incorrect program with a bad calibrate and relying on pre established lines to do your interpretation for you. ?All of this is a result of using Theremino and not using the proper program and calibrations that were designed to do this type of work.?

The Sn La1 at 3.44 keV are ID’d using the pre-assigned labels but it’s actually the K La1 at 3.31. The labeled Sn Lb1 at 3.66 is actually the K Lb1 3.59 which is apparent when using the correct calibration and the DppMCA program to look at it. The difference in energy between the Ka1’s and the Kb1’s is 0.13 and .07 keV. That is the accuracy and precision that a calibration needs to address and that is done using a linear or polynomial regression to establish the energy/channel relationship not a dumb slider in a kid’s program. When you do a regression you can look at the fitting error and correct problems of a wrong peak pick. You’re blind in Theremino.

The Ba La1 ID doesn’t have enough detail to say what it is, but if its Ba then where is the Ba Ka1 at 32.2? and where is the Sn Ka1 at 25.27? Using pre-established lines is a poor crutch for interpretation and leads to? pre-conceived expectations and bad results.

I would suggest leaving the Theremino to NaI applications and start using DppMCA to establish the calibration and do peak interpretations. Get a table listing, in increasing order, the atomic number, it’s element and the Ka1, Ka2, ..La1, La2..etc energies and yields. (see attached) ??In the calibrated DppMCA program start with the prominent peaks and find the max count and centriod, look up that energy in the table and look to see what’s around it paying attention to the Ka1 and La1 and intensities. Find and verify the associated energies of that element, put an ROI around the Ka and La’s. note any weaker lines. One line is not a positive ID it needs corroboration. In the ROI tab click show details and the elements and associated data will be displayed (if it’s in the look up table, if not add it). You can take a screen shot using the Capture Plot (Control C) and add any labels you want to it in Photoshop or whatever.

It’s time to move up.

Dud