I
agree the library is sparse and it doesn¡¯t have both La,b and Ka,b In one library. The auto
peak search routine sucks on noisy data and is hard to tweak. Its best to set
ROI¡¯s manually once you¡¯ve ID¡¯d the peak. It is easy add and make custom
libraries though.
Dud
?
?
toggle quoted message
Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf Of GEOelectronics@...
Sent: Thursday, March 5, 2020 5:53 AM
To: [email protected]
Subject: Re: [XRF] Si-PIN with a view
?
The
DPP Libraries are too general, causing confusion and miss labeling a lot. I've
been making specialty .lib files with special combinations of elements, XRF
lines and Gamma lines. Very few elements in each, but related. They already
have a few like that called "Accident" and "Sources".
-----
Original Message -----
From: Charles David Young <charlesdavidyoung@...>
To: [email protected]
Sent: Wed, 04 Mar 2020 23:07:58 -0500 (EST)
Subject: Re: [XRF] Si-PIN with a view
Ok,
so the deal is that using AgKa1 as one of the points on the E cal line is not
very accurate by the time it gets up to CeKa1 so the peak finder in DppMCA
assumed
that peak was BaKa1.? Use these cal points instead in DppMCA:
You
may ask why I never noticed this discrepancy?? The reason is that I use
DppMCA strictly for collecting data.? The E cal in DppMCA is not
critical.? All analysis is done in my highly customized Theremino where I
can label things nicely.? The table format of
DppMCA just doesn't cut it for me.
Dud,
I made a special decluttered plot just for you.? And in the process I
discovered that the SmKa1 peak that I had previously identified is actually
CeKb2 so this Ce metal is actually a little purer than I thought!
On
Wed, Mar 4, 2020 at 2:44 PM Dude <dfemer@...> wrote:
Charles,
Check
your ¡°slider¡± calibration. This is Ba not Ce. Go back to the
.mca file and look at it with the original cal using the DppMCA program. It
looks like you used Ag for a cal but when was that cal done? Before you ran the
¡°Ce¡± or was it an old one?
Please
clean up the theremino plot, you have so many lines and
labels on their it¡¯s hard to tell what is what. Get rid of anything that¡¯s not
ID¡¯d or an interference anything else is clutter.? One shouldn¡¯t ?do
an interp
based on pre-established labels. Treat each peak separately starting at the low
energy and work your way up ruling out close interferences. Then put an ROI and
?ID label on it and use a real MCA program.? Thermino is great for
NaI but it¡¯ll
get you in trouble with these high res detectors.
There
is no Sm , La or Ce in here and it looks like you were at
83% dead time which is too high which can shift energy and FWHM.
Think
scientifically. The hypothesis was its Ce. You need to prove
that.? I¡¯ll guess you used your pre-established Ce labels and did the
¡°slider¡±
thing to line it all up to a preconceived notion. ??Wrong approach
and guaranteed
to get you in trouble- Don¡¯t use a secondary Cal - use the data acquisition
program to ID peaks.? Look at the periodic table ¨C Ba, La, and Ce line up
so
they are going to have the same spectral structure close energies and look
alike if the cal isn¡¯t right.? An interp starts by looking at each
individual peak
energy and any surrounding interferences with no pre-conceived notions, then
decide
based on Ka,b and La,b and move on to the next. If it doesn¡¯t take you an hour
or more you¡¯re not doing it right. Computer picks suck, stay a long way away ¨C
use your eyes, brains and an energy table.
Dud
?
?
This is from Gunnar Faerber who did his own analysis.?
He is also the one that identified the Betafo speciman as brannerite.
Meanwhile, this is an interesting scan of Ce metal.?
It
is evidently hard to purify it of the other lanthanides because it shows plenty
of Sm and even detectable La.? The La1 and Lb1 peaks echo the Ka1 and Kb1
peaks nicely.? Taken together this set of peaks is quite useful for
calibration from low to high.
?
On Tue, Mar 3, 2020 at 9:03 PM WILLIAM S Dubyk <sdubyk@...> wrote:
Charles, who did you get your specimen of ishikawaite from,
and do you have a microprobe analysis for it? The reason I ask is that out of
curiosity I looked at some of the samarskite analyses from the Petaca district,
and several of the Queen mine specimens may be that mineral. I will ask Al
Falster, who is somewhat of an expert on the samarskite minerals, about what
analyses to use to determine this - oxides versus cation ratios. From my
understanding, this mineral has U+Th greater than Y+REE, and that is what I see
in the Queen mine specimens.
Steve
?
?
|
