Hi Mark,
The material you sent, let's call it CsZr2(PO4)3, was small crystals and seems very stable under the beam, just very small crystals.
If it is not water soluble I'd say we have our candidate Cs standard for bulk synthesis!
Do you have enough money around for starting materials, to try making some bigger crystals that I can better test for homogeneity, beam stability, etc.?
But CsZr2(PO4)3 only contains about 23.5 wt% Cs2O. Natural pollucites contain up to about 40 wt% Cs2O, and it would be nice to have a standard that could be used to analyze for Cs in them (other than another pollucite).
Hi Brian,
You are correct that we would have a raw k-ratio of somewhat under 2 for the matrix correction if we utilized this material as a Cs standard for a high Cs pollucite characterization (actually k-raw = 1.75 in the example below, which I feel is an extrapolation within reason). I do not know how valuable a number the Cs content of a pollucite mineral is geologically and I defer to your expertise on this matter of course.
In any case this Cs standard was/is primarily intended for use as a trace element standard, and of course for this purpose, it almost doesn't matter what we use as a standard, so long as it is stable under the beam (and not water soluble would be nice).
![Smiley :)](https://probesoftware.com/smf/Smileys/default/smiley.gif)
That said, we can examine the matrix correction magnitudes for these two materials and here is our proposed synthetic:
ELEMENT ABSCOR FLUCOR ZEDCOR ZAFCOR STP-POW BKS-COR F(x)u Ec Eo/Ec MACs
Cs la .9985 1.0000 1.2158 1.2140 1.4193 .8567 .9064 5.0120 2.9928 385.778
Zr la 1.0414 .9984 1.0941 1.1377 1.2284 .8907 .7609 2.2230 6.7476 964.694
P ka 1.2197 .9988 .9322 1.1357 .8687 1.0731 .7529 2.1460 6.9897 1000.49
O ka 3.4599 .9998 .8284 2.8655 .7452 1.1116 .2025 .5317 28.2114 7450.29
ELEMENT K-RAW K-VALUE ELEMWT% OXIDWT% ATOMIC% FORMULA KILOVOL
Cs la .00000 .18238 22.142 ----- 5.556 .167 15.00
Zr la .00000 .26715 30.393 ----- 11.111 .333 15.00
P ka .00000 .13630 15.480 ----- 16.667 .500 15.00
O ka .00000 .11162 31.986 ----- 66.667 2.000 15.00
TOTAL: 100.000 ----- 100.000 3.000
And here is a natural pollucite from Rossman with a high Cs concentration:
ELEMENT ABSCOR FLUCOR ZEDCOR ZAFCOR STP-POW BKS-COR F(x)u Ec Eo/Ec MACs
Cs la .9648 1.0000 1.2478 1.2038 1.4785 .8439 .9381 5.0120 2.9928 250.373
Si ka 1.5404 .9989 .9203 1.4161 .8678 1.0606 .5879 1.8390 8.1566 1974.48
Al ka 1.7391 .9925 .9451 1.6313 .8841 1.0690 .5102 1.5600 9.6154 2557.00
Na ka 2.8865 .9977 .9325 2.6853 .8611 1.0829 .2916 1.0730 13.9795 5371.51
O ka 2.0263 .9996 .8511 1.7239 .7787 1.0931 .3458 .5317 28.2114 4171.30
ELEMENT K-RAW K-VALUE ELEMWT% OXIDWT% ATOMIC% FORMULA KILOVOL
Cs la .00000 .32090 38.630 ----- 8.000 .167 15.00
Si ka .00000 .11529 16.326 ----- 16.000 .333 15.00
Al ka .00000 .04807 7.842 ----- 8.000 .167 15.00
Na ka .00000 .02488 6.682 ----- 8.000 .167 15.00
O ka .00000 .17534 30.227 ----- 52.000 1.083 15.00
H .293 ----- 8.001 .167
TOTAL: 100.000 ----- 100.000 2.083
As you can see, the difference in the matrix corrections is under 1%, so I don't think it is a significant concern even for major element analytical work. In fact the difference in the matrix corrections is probably smaller than the uncertainty in the Cs concentration in existing natural pollucite standards... I'm guessing.
Of course there is also the statistics of the extrapolation, but a factor of less than 2 should still provide reasonable analytical sensitivity.
Please feel free to explain further if I have missed your point.
john