Probe Software Users Forum
Software => Probe for EPMA => Topic started by: John Donovan on July 05, 2013, 09:34:51 AM
-
A recent modification in v. 10.0.4 of PFE allows the user to review the TDI intensity data for *all* samples, which have TDI data acquired, from the Run | Display Time Dependent (TDI) and Alternating (on/off) Intensities menu.
The change now allows the user to see intensity data for TDI channels even if those data points have *not* been assigned the TDI correction, and in addition, the program now adds the string "(TDI off) to those data points to indicate that they are not using the TDI correction, though TDI data was acquired and is available for assignment as seen here:
(https://probesoftware.com/smf/oldpics/i41.tinypic.com/2nc2937.jpg)
-
The Time Dependent Intensity (TDI) correction for changes in x-ray intensity as a function of acquisition time is well known though not completely understood. The physics of ion migration/volatilization as a function of thermal conductivity, ion mobility and electron dose is complex and very likely convolves together several different physical processes with different time scales.
But for the purposes of correcting for this artifact since the sample is what it is, we are left with reducing beam current, increasing beam diameter, decreasing beam exposure (acquisition) time, cooling the sample cryogenically or some combination of these procedures along with a software correction for these effects which, depending on the element, can result in decreases or increases in x-ray intensity over time.
A typical hydrous glass with a normal (log-linear) TDI correction for Na, Si, Al (and Ca and Ti) is shown here:
ELEM: Na Si K Al Mg Ca Ti Mn Fe P Cr O H
TYPE: ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL CALC SPEC
BGDS: MAN MAN LIN MAN MAN MAN LIN LIN MAN EXP LIN
TIME: 80.00 30.00 40.00 40.00 60.00 80.00 20.00 20.00 60.00 60.00 30.00
BEAM: 20.08 20.08 20.08 20.08 20.08 20.08 20.08 20.08 20.08 20.08 20.08
ELEM: Na Si K Al Mg Ca Ti Mn Fe P Cr O H SUM
235 .315 26.882 .449 4.251 5.416 4.877 .925 .343 11.099 .199 .055 44.303 .000 99.113
236 .487 26.014 .526 4.256 1.367 5.613 .932 .344 16.725 .194 .027 42.621 .000 99.107
237 .396 26.547 .455 4.244 4.251 5.551 .907 .344 12.211 .192 .037 43.735 .000 98.870
238 .359 26.017 .452 4.177 2.586 5.918 .892 .359 14.556 .195 .033 42.777 .000 98.320
AVER: .389 26.365 .471 4.232 3.405 5.490 .914 .348 13.648 .195 .038 43.359 .000 98.852
SDEV: .073 .426 .037 .037 1.787 .439 .018 .008 2.507 .003 .012 .799 .000 .373
SERR: .037 .213 .018 .018 .894 .220 .009 .004 1.254 .001 .006 .400 .000
%RSD: 18.77 1.62 7.83 .87 52.49 8.00 2.01 2.18 18.37 1.49 31.81 1.84 .00
TDI%: 27.702 -.037 ---- -.154 ---- -1.026 .563 ---- ---- ---- ---- ---- ----
DEV%: 10.3 .6 ---- 1.1 ---- 2.9 8.2 ---- ---- ---- ---- ---- ----
TDIF: LINEAR LINEAR ---- LINEAR ---- LINEAR LINEAR ---- ---- ---- ---- ---- ----
TDIT: 97.00 48.75 ---- 58.00 ---- 98.75 37.00 ---- ---- ---- ---- ---- ----
TDII: 72.0 10400. ---- 1897. ---- 169. 98.3 ---- ---- ---- ---- ---- ----
As we can see, the TDI % log-linear correction above highlighted in red, is approximately 28% which seems reasonable until one examines the actual extrapolation to zero time, and then a problem is obvious:
(https://probesoftware.com/smf/oldpics/i39.tinypic.com/k37w9w.jpg)
Clearly the intensity change over time is more than a simple exponential.
However, by fitting the log intensity to a quadratic and extrapolating again, we obtain the following results as shown below:
ELEM: Na Si K Al Mg Ca Ti Mn Fe P Cr O H
TYPE: ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL CALC SPEC
BGDS: MAN MAN LIN MAN MAN MAN LIN LIN MAN EXP LIN
TIME: 80.00 30.00 40.00 40.00 60.00 80.00 20.00 20.00 60.00 60.00 30.00
BEAM: 20.08 20.08 20.08 20.08 20.08 20.08 20.08 20.08 20.08 20.08 20.08
ELEM: Na Si K Al Mg Ca Ti Mn Fe P Cr O H
TYPE: ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL CALC SPEC
BGDS: MAN MAN LIN MAN MAN MAN LIN LIN MAN EXP LIN
TIME: 80.00 30.00 40.00 40.00 60.00 80.00 20.00 20.00 60.00 60.00 30.00
BEAM: 20.08 20.08 20.08 20.08 20.08 20.08 20.08 20.08 20.08 20.08 20.08
ELEM: Na Si K Al Mg Ca Ti Mn Fe P Cr O H SUM
235 .436 26.890 .449 4.253 5.421 4.876 .925 .343 11.099 .199 .055 44.359 .000 99.306
236 .584 26.021 .526 4.258 1.368 5.613 .932 .344 16.725 .194 .027 42.665 .000 99.257
237 .461 26.551 .455 4.245 4.253 5.551 .907 .344 12.211 .192 .037 43.766 .000 98.973
238 .450 26.023 .452 4.179 2.588 5.918 .892 .359 14.556 .195 .033 42.818 .000 98.462
AVER: .483 26.371 .471 4.234 3.407 5.490 .914 .348 13.648 .195 .038 43.402 .000 99.000
SDEV: .068 .427 .037 .037 1.789 .439 .018 .008 2.507 .003 .012 .803 .000 .387
SERR: .034 .213 .018 .018 .894 .220 .009 .004 1.254 .001 .006 .401 .000
%RSD: 14.19 1.62 7.83 .87 52.50 8.00 2.01 2.18 18.37 1.49 31.81 1.85 .00
TDI%: 54.831 -.037 ---- -.154 ---- -1.026 .563 ---- ---- ---- ---- ---- ----
DEV%: 5.9 .6 ---- 1.1 ---- 2.9 8.2 ---- ---- ---- ---- ---- ----
TDIF: QUADRA LINEAR ---- LINEAR ---- LINEAR LINEAR ---- ---- ---- ---- ---- ----
TDIT: 97.00 48.75 ---- 58.00 ---- 98.75 37.00 ---- ---- ---- ---- ---- ----
TDII: 87.2 10400. ---- 1897. ---- 169. 98.3 ---- ---- ---- ---- ---- ----
This was accomplished by merely regressing with the "hyper-exponential" fit shown here in the Standard Assignments dialog for Na:
(https://probesoftware.com/smf/oldpics/i40.tinypic.com/2dbru5y.jpg)
Therefore, one may improve the accuracy of the TDI correction considerably without having to reduce beam current or increase beam diameter, as shown in the "hyper-exponential" fit below:
(https://probesoftware.com/smf/oldpics/i44.tinypic.com/30cah03.jpg)
-
The importance of the matrix correction in these types of beam sensitive samples (e.g., hydrated) may be illustrated with the following data:
Results in Oxide Weight Percents
ELEM: CaO K2O FeO SiO2 MgO Na2O Al2O3 TiO2 P2O5 O H2O SUM
58 .411 4.900 .537 74.603 .036 2.644 11.975 .073 .000 .000 .000 95.180
59 .437 4.624 .612 75.386 .033 1.841 12.024 .113 .000 .000 .000 95.070
60 .423 4.998 .526 74.715 .023 2.765 12.113 .065 .000 .000 .000 95.628
61 .423 4.853 .637 75.000 .047 2.137 12.089 .055 .000 .000 .000 95.240
62 .435 4.847 .677 74.613 .048 2.561 12.089 .036 .011 .000 .000 95.317
AVER: .426 4.844 .598 74.863 .037 2.390 12.058 .068 .002 .000 .000 95.287
SDEV: .011 .137 .065 .333 .010 .387 .057 .028 .005 .000 .000
SERR: .005 .061 .029 .149 .005 .173 .025 .013 .002 .000 .000
%RSD: 2.5 2.8 10.8 .4 27.9 16.2 .5 41.5 223.6 418.3 .0
ZCOR: 1.1202 1.1536 1.1987 1.2061 1.4303 1.8227 1.2568 1.1983 1.4641 .0000 .0000
KRAW: .0161 .3080 .0057 1.0344 .0003 .1323 .7242 .0006 -.0004 .0000 .0000
PKBG: 4.96 59.36 4.84 370.59 1.42 30.93 77.40 1.46 .87 .00 .00
The above analysis was performed without a TDI correction and also without specifying water in the matrix correction. The water by difference calculation yields approximately 4.7 wt% H2O. Note the average SiO2 and Na2O concentrations highlighted in red for comparison with the results below.
Next we specify the TDI correction as described above and obtain the results shown here:
Results in Oxide Weight Percents
ELEM: CaO K2O FeO SiO2 MgO Na2O Al2O3 TiO2 P2O5 O H2O SUM
58 .411 4.867 .537 74.378 .037 3.626 12.035 .030 .000 .000 .000 95.921
59 .437 4.740 .612 75.016 .034 2.426 12.063 .194 .000 .000 .000 95.521
60 .423 4.933 .526 74.057 .024 3.805 12.178 .076 .000 .000 .000 96.022
61 .423 5.220 .636 74.552 .048 3.025 12.147 .077 .000 .000 .000 96.128
62 .435 4.715 .677 74.794 .049 3.503 12.146 .048 .011 .000 .000 96.378
AVER: .426 4.895 .598 74.559 .038 3.277 12.114 .085 .002 .000 .000 95.994
SDEV: .011 .203 .065 .370 .010 .557 .062 .064 .005 .000 .000
SERR: .005 .091 .029 .166 .005 .249 .028 .029 .002 .000 .000
%RSD: 2.5 4.1 10.8 .5 27.3 17.0 .5 75.6 223.6 .0 .0
ZCOR: 1.1198 1.1530 1.1983 1.2092 1.4391 1.8180 1.2625 1.1979 1.4627 .0000 .0000
KRAW: .0161 .3114 .0057 1.0276 .0003 .1819 .7242 .0008 -.0004 .0000 .0000
PKBG: 4.97 60.00 4.84 369.28 1.43 42.09 77.77 1.58 .87 .00 .00
INT%: .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00
VOL%: .000 1.135 .000 -.658 .000 36.111 .000 20.283 .000 .000 .000
DEV%: .0 .2 .0 .0 .0 .4 .0 20.3 .0 .0 .0
The above analysis was performed *with* the TDI correction, but still without specifying water in the matrix correction. The water by difference calculation now yields approximately 4.0 wt% H2O. Note also that due to the TDI correction, the SiO2 concentration has decreased slightly and the Na2O concentration has increased significantly as highlighted in red.
Finally, we specify water in the matrix correction and obtain the results shown here:
Results in Oxide Weight Percents
ELEM: CaO K2O FeO SiO2 MgO Na2O Al2O3 TiO2 P2O5 O H2O SUM
58 .414 4.885 .542 74.776 .039 3.668 12.139 .030 .000 .000 3.506 100.000
59 .441 4.759 .618 75.464 .036 2.457 12.181 .195 .000 .000 3.849 100.000
60 .426 4.951 .531 74.441 .026 3.848 12.281 .076 .000 .000 3.420 100.000
61 .426 5.239 .641 74.934 .050 3.058 12.249 .077 .000 .000 3.327 100.000
62 .438 4.730 .682 75.149 .051 3.539 12.240 .048 .011 .000 3.112 100.000
AVER: .429 4.913 .603 74.953 .041 3.314 12.218 .085 .002 .000 3.443 100.000
SDEV: .011 .203 .065 .385 .010 .562 .057 .065 .005 .000 .270
SERR: .005 .091 .029 .172 .005 .251 .025 .029 .002 .000 .121
%RSD: 2.5 4.1 10.8 .5 25.7 16.9 .5 75.6 223.6 -104.6 7.9
ZCOR: 1.1241 1.1571 1.2053 1.2156 1.4515 1.8372 1.2731 1.2037 1.4591 .0000 .0000
KRAW: .0161 .3114 .0057 1.0276 .0004 .1821 .7244 .0008 -.0004 .0000 .0000
PKBG: 5.03 60.00 4.89 372.20 1.46 43.35 78.99 1.58 .87 .00 .00
INT%: .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00
VOL%: .000 1.135 .000 -.658 .000 36.111 .000 20.283 .000 .000 .000
DEV%: .0 .2 .0 .0 .0 .4 .0 20.3 .0 .0 .0
It is quite interesting to note that by simply adding water to the matrix correction, the concentration of the Si is significantly increased resulting in a water by difference calculation that now yields approximately 3.4 wt% H2O. Note that both the average SiO2 and Na2O concentrations have increased as seen highlighted in red.
This is due to the fact that water (mostly oxygen) absorbs Si Ka (and most of the other emission lines here) more strongly than Si, thus resulting in larger Si (and other elements) and smaller H2O values when the matrix effects of H2O are included in the matrix correction.
-
Don't forget your beam sensitive standards!
By checking the little box here in the Special Options dialog (from Acquire!) (thanks to Paul Carpenter for the idea):
(https://probesoftware.com/smf/oldpics/i41.tinypic.com/106yna0.jpg)
you can also perform TDI corrections on your beam sensitive standards. E.g., anhydrite, apatite, etc:
(https://probesoftware.com/smf/oldpics/i43.tinypic.com/2vvnucp.jpg)
However, note that Ca here could be perhaps better fit using the quadratic (hyper-exponential) fit as seen here:
(https://probesoftware.com/smf/oldpics/i44.tinypic.com/fu1cnm.jpg)
Also, if you are measuring oxygen, this element intensity is often affected by beam damage:
(https://probesoftware.com/smf/oldpics/i40.tinypic.com/902khs.jpg)
Happy probing!
-
Hi All
I'm looking through the literature to get a feel for who's done what using the TDI correction in PfEPMA.
Can you please point me toward any recent (not old) publications you know about or have written.
Thanks
Richard
-
I'm looking through the literature to get a feel for who's done what using the TDI correction in PfEPMA.
Can you please point me toward any recent (not old) publications you know about or have written.
I have to issue a big apology here. :'(
I have been swamped these last few years with other work and have not taken the time to properly document the new TDI methods I've developed recently and which are still on going... ;D
Normally, I try to publish everything that is worthwhile, primarily so it is scientifically documented, but also so every feature in the software gets its proper "bona fides" so to speak!
I have asked a couple of younger colleagues to help me write up these TDI methods into a full paper but that process has only just got going last year, though we hope to have something finished this year.
In the meantime I have some links to abstracts here:
Glass abstract with Michael Rowe:
http://epmalab.uoregon.edu/pdfs/gold2005_Donovan.pdf
The presentation for the above abstract:
http://epmalab.uoregon.edu/reports/Improving%20Glass%20Analyses.pdf
A white paper on TDI effects when measuring Na, Si and O in hydrous glasses (method of B. Nash, et al.):
http://epmalab.uoregon.edu/reports/Withers%20hydrous%20glass.pdf
-
Here is some additional explanation of the log window output for TDI sample quantitative correction results:
Un 27 MAM IW2 C4-ext-1, Results in Elemental Weight Percents
ELEM: Na Si K Al Mg Ca Ti Mn Fe P Cr O H
TYPE: ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL CALC SPEC
BGDS: MAN MAN LIN MAN MAN MAN LIN LIN MAN EXP LIN
TIME: 79.98 29.98 40.00 40.00 60.00 80.00 20.00 20.00 60.00 60.00 30.00
BEAM: 20.09 20.09 20.09 20.09 20.09 20.09 20.09 20.09 20.09 20.09 20.09
ELEM: Na Si K Al Mg Ca Ti Mn Fe P Cr O H SUM
223 .507 25.693 .391 4.354 4.390 5.922 1.025 .385 12.555 .207 .024 43.328 .000 98.780
224 .256 25.891 .329 4.272 4.917 5.856 .863 .372 10.511 .181 .032 42.976 .000 96.457
225 .333 26.002 .390 4.423 3.930 6.318 1.008 .340 12.968 .196 .032 43.620 .000 99.559
226 .351 25.804 .379 4.197 4.793 5.837 .954 .338 12.482 .191 .055 43.403 .000 98.784
227 .289 26.034 .374 4.350 5.419 5.865 .955 .338 11.326 .193 .046 43.869 .000 99.057
228 .308 25.807 .365 4.239 4.010 6.126 .903 .333 13.373 .186 .037 43.230 .000 98.918
AVER: .341 25.872 .371 4.306 4.577 5.987 .951 .351 12.203 .193 .037 43.404 .000 98.593
SDEV: .088 .130 .023 .084 .574 .194 .061 .022 1.076 .009 .011 .310 .000 1.085
SERR: .036 .053 .009 .034 .234 .079 .025 .009 .439 .004 .005 .127 .000
%RSD: 25.76 .50 6.16 1.95 12.54 3.24 6.43 6.15 8.82 4.60 29.73 .72 .00
STDS: 336 162 374 336 162 162 22 25 162 285 396 0 0
STKF: .0735 .2018 .1132 .1331 .0568 .1027 .5547 .7341 .0950 .1599 .3050 .0000 .0000
STCT: 2515.7 10026.0 6009.1 8230.4 2834.3 337.0 6393.2 14939.3 599.4 9652.2 5184.8 .0 .0
UNKF: .0016 .2045 .0034 .0306 .0293 .0557 .0082 .0029 .1039 .0014 .0003 .0000 .0000
UNCT: 55.4 10158.6 178.3 1893.2 1460.9 182.6 94.5 59.8 655.3 82.5 5.6 .0 .0
UNBG: 10.4 9.8 30.1 28.5 19.0 1.5 7.6 19.2 8.0 39.1 14.8 .0 .0
ZCOR: 2.1042 1.2653 1.1057 1.4062 1.5655 1.0759 1.1608 1.1946 1.1745 1.4095 1.1305 .0000 .0000
KRAW: .0220 1.0132 .0297 .2300 .5154 .5420 .0148 .0040 1.0933 .0085 .0011 .0000 .0000
PKBG: 6.34 1039.69 6.95 67.51 77.70 126.12 13.71 4.12 82.50 3.12 1.39 .00 .00
INT%: ---- ---- ---- ---- -.11 ---- ---- ---- .00 ---- ---- ---- ----
TDI%: 39.559 -.098 ---- -.185 ---- -1.692 -.502 ---- ---- ---- ---- ---- ----
DEV%: 4.8 .6 ---- 1.1 ---- 2.6 7.5 ---- ---- ---- ---- ---- ----
TDIF: QUADRA LINEAR ---- LINEAR ---- LINEAR LINEAR ---- ---- ---- ---- ---- ----
TDIT: 98.33 49.83 ---- 58.33 ---- 98.33 37.83 ---- ---- ---- ---- ---- ----
TDII: 64.7 10169. ---- 1921. ---- 184. 102. ---- ---- ---- ---- ---- ----
Here is a "key":
(https://probesoftware.com/smf/oldpics/i58.tinypic.com/29qb14m.jpg)
-
Here's a TDI plot for some points in a high crystallized basalt where the student was trying to find the residual glass chemistry, but often hit some crystals.
Even though the chemistry of the two phases are very similar, the glass compositions are easily distinguished from the crystal compositions:
(https://probesoftware.com/smf/oldpics/i59.tinypic.com/rkx18h.jpg)
-
That is very nice 8)
-
This is an "extreme" situation, but if you ever have to characterize a Na rich glass such as NIST K-375 (which would never occur naturally I think!), the TDI correction in PFE will come to your rescue. In this case even the linear and hyper exponential TDI regressions will under fit this type of Na loss over time.
But the double exponential TDI correction seen here:
(https://probesoftware.com/smf/oldpics/i62.tinypic.com/j0zls0.jpg)
can offer some help, though this is a scary extrapolation for sure as you can see:
(https://probesoftware.com/smf/oldpics/i59.tinypic.com/ixfhwo.jpg)
Basically in this case, one is losing over 50% of the Na intensity in less than 8 seconds after the faraday cup is removed!
How accurate is the extrapolation this particular case? I hesitate to reveal, but.... all in the name of science, here it is:
St 173 Set 24 K-0375 NBS glass
TakeOff = 40.0 KiloVolt = 15.0 Beam Current = 100. Beam Size = 10
(Magnification (analytical) = 40000), Beam Mode = Analog Spot
(Magnification (default) = 400, Magnification (imaging) = 800)
Image Shift (X,Y): .00, .00
Number of Data Lines: 5 Number of 'Good' Data Lines: 5
First/Last Date-Time: 05/10/2012 02:30:56 AM to 05/10/2012 02:38:17 AM
WARNING- Using Exponential Off-Peak correction for si ka
WARNING- Using Exponential Off-Peak correction for p ka
WARNING- Using Time Dependent Intensity (TDI) Element Correction
WARNING- Using Time Dependent Intensity (TDI) Weighting Factor of 10
Average Total Oxygen: .000 Average Total Weight%: 98.935
Average Calculated Oxygen: .000 Average Atomic Number: 16.454
Average Excess Oxygen: .000 Average Atomic Weight: 22.833
Average ZAF Iteration: 4.00 Average Quant Iterate: 2.00
St 173 Set 24 K-0375 NBS glass, Results in Elemental Weight Percents
ELEM: Na Si Ca Fe P Zn Ba U O
TYPE: ANAL ANAL ANAL ANAL ANAL SPEC SPEC SPEC SPEC
BGDS: LIN EXP LIN LIN EXP
TIME: 20.00 20.00 20.00 20.00 20.00
BEAM: 100.72 100.72 100.72 100.72 100.72
ELEM: Na Si Ca Fe P Zn Ba U O SUM
371 9.539 32.765 .001 .007 .004 4.940 10.370 .110 42.320 100.056
372 8.727 32.573 .005 -.008 .012 4.940 10.370 .110 42.320 99.049
373 9.551 32.345 .008 -.014 .014 4.940 10.370 .110 42.320 99.644
374 8.440 32.289 .001 -.029 .008 4.940 10.370 .110 42.320 98.450
375 7.829 31.913 .001 .013 -.021 4.940 10.370 .110 42.320 97.476
AVER: 8.817 32.377 .003 -.006 .003 4.940 10.370 .110 42.320 98.935
SDEV: .739 .321 .003 .017 .014 .000 .000 .000 .000 1.017
SERR: .331 .144 .001 .008 .006 .000 .000 .000 .000
%RSD: 8.38 .99 89.41 -273.00 412.33 .00 .00 .00 .00
PUBL: 10.420 31.830 n.a. n.a. n.a. 4.940 10.370 .110 42.320 99.990
%VAR: -15.38 1.72 --- --- --- .00 .00 .00 .00
DIFF: -1.603 .547 --- --- --- .000 .000 .000 .000
STDS: 336 14 285 162 285 0 0 0 0
STKF: .0735 .4101 .3596 .0950 .1599 .0000 .0000 .0000 .0000
STCT: 78.78 80.11 605.49 66.49 40.15 .00 .00 .00 .00
UNKF: .0427 .2552 .0000 -.0001 .0000 .0000 .0000 .0000 .0000
UNCT: 45.72 49.86 .05 -.04 .01 .00 .00 .00 .00
UNBG: 3.34 .16 1.23 .99 .05 .00 .00 .00 .00
ZCOR: 2.0679 1.2685 1.0646 1.1515 1.4651 .0000 .0000 .0000 .0000
KRAW: .5803 .6224 .0001 -.0006 .0001 .0000 .0000 .0000 .0000
PKBG: 14.69 308.09 1.04 .97 1.26 .00 .00 .00 .00
TDI%: 4918.968 -8.230 1.354 ---- ---- ---- ---- ---- ----
DEV%: 9.8 .4 32.9 ---- ---- ---- ---- ---- ----
TDIF: LOG-LOG LOG-LOG LOG-LIN ---- ---- ---- ---- ---- ----
TDIT: 74.20 74.40 71.80 ---- ---- ---- ---- ---- ----
TDII: 45.6 49.9 1.29 ---- ---- ---- ---- ---- ----
So, ok we are off by some 15% relative error for Na, *but* the TDI% correction is almost 5000%. That is not a typo! :o
And... we are *still* under fitting the data! How about a triple exponential, anyone?
That is what happens when you use a 100 nA beam on such a beam sensitive material...
-
I am trying to toggle the TDI on and off to see "what if". I am using the 9.6.3 PfE flavor on our SX51 which will continue operation for several more years. Regardless of _3_ ways of trying to turn off the TDI to see what the integrated count would be, nothing seems to work. The 3 ways are (1) in the Analytical/Analysis Options, uncheck the Use assigned or Self TDI corrections on Unknown box, (2) Assignment properties, click the No TDI Califbration Correction radio button, (3) under Standard and Interference Assignments, click the Remove TDI Correction. Have other people successfully been able to 'turn off' and see the difference in counts?? No matter what I do, I see the same counts. I am using "Self" Calibration. I have imported the mdb file into a "modern" 10.5.3 version and see the same behavior. Suggestions?
-
I am trying to toggle the TDI on and off to see "what if". I am using the 9.6.3 PfE flavor on our SX51 which will continue operation for several more years. Regardless of _3_ ways of trying to turn off the TDI to see what the integrated count would be, nothing seems to work. The 3 ways are (1) in the Analytical/Analysis Options, uncheck the Use assigned or Self TDI corrections on Unknown box, (2) Assignment properties, click the No TDI Califbration Correction radio button, (3) under Standard and Interference Assignments, click the Remove TDI Correction. Have other people successfully been able to 'turn off' and see the difference in counts?? No matter what I do, I see the same counts. I am using "Self" Calibration. I have imported the mdb file into a "modern" 10.5.3 version and see the same behavior. Suggestions?
John,
The way to tell if the TDI corrections are on or off is to look for this output in the log window when the quant is calculated:
TDI%: 5.145 .038 ---- .222 ---- .434 -.063 ---- ---- ---- ---- ---- ----
DEV%: .4 .1 ---- .1 ---- .4 1.0 ---- ---- ---- ---- ---- ----
TDIF: LOG-LIN LOG-LIN ---- LOG-LIN ---- LOG-LIN LOG-LIN ---- ---- ---- ---- ---- ----
TDIT: 99.17 49.67 ---- 58.33 ---- 98.50 37.67 ---- ---- ---- ---- ---- ----
TDII: 254. 9873. ---- 3037. ---- 230. 146. ---- ---- ---- ---- ---- ----
You can also use the Remove TDI Correction button from the Standard Assignments dialog.
-
I'm assuming this error is a result of poor sequencing choices on my part, so obviously I need to structure my future setups so that no TDI's are needed for the last-measured sample of any "Combine Samples" projects. In this case, the elements for which TDI's were really necessary were all the second sample because... well, I'm an idiot. However, if anyone can suggest a workaround, I'd be mighty grateful.
Hi Owen,
Sad to say, the "loose nut behind the wheel" in this case is me!
I'll have to add code to handle the TDI intensities in the second sample. The issue is I need to properly re-normalize the TDI intensities from the 2nd condition to be consistent with the first sample conditions.
Please send me a small MDB file example of the issue and I will work on it ASAP.
Thanks!
john
-
I took a shot this morning and acquired some time dependent intensity (TDI) data on the NBS K-373 and K-375 Na-Zn-Ba silicate glasses. Conditions were 15 keV, 30 nA and 5 um beam. 20 TDI and absorbed current measurements were made over a 30 sec counting time (using MAN bgds) as seen here:
(https://probesoftware.com/smf/oldpics/i61.tinypic.com/2lacyab.jpg)
and here:
(https://probesoftware.com/smf/oldpics/i59.tinypic.com/v2w8xi.jpg)
Because of the extreme beam sensitivity of these two materials (10.4 elemental wt% Na), the double exponential (log-log), extrapolation to zero time is required. Quantification gives the following results for K-373:
ELEM: Na Si Zn Ba U O SUM
10 9.772 31.850 4.940 10.380 .054 42.340 99.336
11 9.944 31.850 4.940 10.380 .054 42.340 99.508
12 9.336 31.850 4.940 10.380 .054 42.340 98.900
AVER: 9.684 31.850 4.940 10.380 .054 42.340 99.248
SDEV: .314 .000 .000 .000 .000 .000 .314
SERR: .181 .000 .000 .000 .000 .000
%RSD: 3.24 .00 .00 .00 .00 .00
PUBL: 10.430 31.850 4.940 10.380 .054 42.340 99.994
%VAR: -7.15 .00 .00 .00 .00 .00
DIFF: -.746 .000 .000 .000 .000 .000
STDS: 301 0 0 0 0 0
STKF: .0510 .0000 .0000 .0000 .0000 .0000
STCT: 2902.3 .0 .0 .0 .0 .0
UNKF: .0470 .0000 .0000 .0000 .0000 .0000
UNCT: 2671.4 .0 .0 .0 .0 .0
UNBG: 27.7 .0 .0 .0 .0 .0
ZCOR: 2.0624 .0000 .0000 .0000 .0000 .0000
KRAW: .9204 .0000 .0000 .0000 .0000 .0000
PKBG: 97.30 .00 .00 .00 .00 .00
TDI%: 270.919 ---- ---- ---- ---- ----
DEV%: .6 ---- ---- ---- ---- ----
TDIF: LOG-LOG ---- ---- ---- ---- ----
TDIT: 53.67 ---- ---- ---- ---- ----
TDII: 2698. ---- ---- ---- ---- ----
and here for K-375:
ELEM: Na Si Zn Ba U O SUM
13 9.460 31.830 4.940 10.370 .110 42.320 99.030
14 8.583 31.830 4.940 10.370 .110 42.320 98.153
15 9.695 31.830 4.940 10.370 .110 42.320 99.265
AVER: 9.246 31.830 4.940 10.370 .110 42.320 98.816
SDEV: .586 .000 .000 .000 .000 .000 .586
SERR: .339 .000 .000 .000 .000 .000
%RSD: 6.34 .00 .00 .00 .00 .00
PUBL: 10.420 31.830 4.940 10.370 .110 42.320 99.990
%VAR: -11.27 .00 .00 .00 .00 .00
DIFF: -1.174 .000 .000 .000 .000 .000
STDS: 301 0 0 0 0 0
STKF: .0510 .0000 .0000 .0000 .0000 .0000
STCT: 2902.3 .0 .0 .0 .0 .0
UNKF: .0447 .0000 .0000 .0000 .0000 .0000
UNCT: 2543.9 .0 .0 .0 .0 .0
UNBG: 27.8 .0 .0 .0 .0 .0
ZCOR: 2.0680 .0000 .0000 .0000 .0000 .0000
KRAW: .8765 .0000 .0000 .0000 .0000 .0000
PKBG: 92.61 .00 .00 .00 .00 .00
TDI%: 236.546 ---- ---- ---- ---- ----
DEV%: .6 ---- ---- ---- ---- ----
TDIF: LOG-LOG ---- ---- ---- ---- ----
TDIT: 52.67 ---- ---- ---- ---- ----
TDII: 2568. ---- ---- ---- ---- ----
Although the relative accuracy errors are still around 10%, the TDI correction is over 200%! What does that mean? Well, it means that if you didn't use the TDI correction, you'd get a roughly 70% error, even with these relatively mild conditions:
ELEM: Na Si Zn Ba U O SUM
13 2.929 31.830 4.940 10.370 .110 42.320 92.499
14 2.866 31.830 4.940 10.370 .110 42.320 92.436
15 2.852 31.830 4.940 10.370 .110 42.320 92.422
AVER: 2.882 31.830 4.940 10.370 .110 42.320 92.452
SDEV: .041 .000 .000 .000 .000 .000 .041
SERR: .024 .000 .000 .000 .000 .000
%RSD: 1.41 .00 .00 .00 .00 .00
PUBL: 10.420 31.830 4.940 10.370 .110 42.320 99.990
%VAR: -72.34 .00 .00 .00 .00 .00
DIFF: -7.538 .000 .000 .000 .000 .000
STDS: 301 0 0 0 0 0
But I'm also curious about the fact that the two very similar materials show changes in absorbed current that are opposite of each other even though they have just a slight difference in uranium content.
-
Although the relative accuracy errors are still around 10%, the TDI correction is over 200%! What does that mean? Well, it means that if you didn't use the TDI correction, you'd get a roughly 70% error, even with these relatively mild conditions...
Here are the same data but with the "TDI weighting" feature applied as seen here:
(https://probesoftware.com/smf/oldpics/i58.tinypic.com/2you5iq.jpg)
Here are the results for the K-373 standard. Note that we now obtain around 5% relative accuracy even with an almost 300% TDI correction!
ELEM: Na Si Zn Ba U O SUM
10 9.992 31.850 4.940 10.380 .054 42.340 99.556
11 10.468 31.850 4.940 10.380 .054 42.340 100.032
12 9.130 31.850 4.940 10.380 .054 42.340 98.694
AVER: 9.864 31.850 4.940 10.380 .054 42.340 99.428
SDEV: .678 .000 .000 .000 .000 .000 .678
SERR: .392 .000 .000 .000 .000 .000
%RSD: 6.88 .00 .00 .00 .00 .00
PUBL: 10.430 31.850 4.940 10.380 .054 42.340 99.994
%VAR: -5.43 .00 .00 .00 .00 .00
DIFF: -.566 .000 .000 .000 .000 .000
STDS: 301 0 0 0 0 0
STKF: .0510 .0000 .0000 .0000 .0000 .0000
STCT: 2939.1 .0 .0 .0 .0 .0
UNKF: .0479 .0000 .0000 .0000 .0000 .0000
UNCT: 2758.6 .0 .0 .0 .0 .0
UNBG: 27.8 .0 .0 .0 .0 .0
ZCOR: 2.0602 .0000 .0000 .0000 .0000 .0000
KRAW: .9386 .0000 .0000 .0000 .0000 .0000
PKBG: 100.40 .00 .00 .00 .00 .00
TDI%: 283.286 ---- ---- ---- ---- ----
DEV%: .5 ---- ---- ---- ---- ----
TDIF: LOG-LOG ---- ---- ---- ---- ----
TDIT: 53.67 ---- ---- ---- ---- ----
TDII: 2781. ---- ---- ---- ---- ----
This is what it looks like with the weighted fitting. Still slightly, slightly under fit...
(https://probesoftware.com/smf/oldpics/i62.tinypic.com/a9preq.jpg)
Note that this is a log-log (double exponential) fit and still not quite enough curvature. Now that's what I call Na loss! But as long as the precision of our measurements are good enough, we can continue to push our modeling accuracy.
-
Here are the same data but with the "TDI weighting" feature applied as seen here:
(https://probesoftware.com/smf/oldpics/i58.tinypic.com/2you5iq.jpg)
So is it worth allowing more than a factor of 10 "weighting" to the initial TDI measured points?
-
Was wondering if I could throw a quick question to the group about combining TDI's and multiple setups/samples using the nice "Combine Selected Samples" option in Analyze. Apologies if this has already been discussed elsewhere, but I haven't been able to find mention of this error message in either the documentation or other forum threads.
For this particular project, I have two Unknown samples to combine. Each was run with different sample setup (i.e. different element and beam conditions). TDI's were enabled for both setups, and there are no duplicate elements between each setup.
Thanks,
OKN
Hi Owen,
This is fixed now, but in a slightly different manner than you might have been expecting.
When the samples are combined using the Analyze! | Combine Selected Samples button, a temporary sample is created with the elements from all selected samples. The problem with TDI is that the TDI is actually based on the sample number and data row and channel. But since the TDI data for a combined sample comes from multiple samples there is no way indicate where the TDI intensities should be loaded from once the channels are combined.
So you have two samples selected at different beam energies, both with TDI acquisition, first sample here:
Un 3 SON68_20kV, Results in Elemental Weight Percents
ELEM: Ba La Ce Pr Cr Nd Mn Fe Ni Zn Ca Te Cs O H Li
TYPE: ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL CALC SPEC DIFF
BGDS: LIN LIN S-Lo LIN LIN LIN LIN LIN LIN LIN EXP LIN EXP
TIME: 30.00 30.00 30.00 30.00 30.00 30.00 40.00 20.00 40.00 20.00 40.00 60.00 60.00
BEAM: 15.00 15.00 15.00 15.00 15.00 15.00 15.00 15.00 15.00 15.00 15.00 15.00 15.00
AGGR:
ELEM: Ba La Ce Pr Cr Nd Mn Fe Ni Zn Ca Te Cs O H Li SUM
129 .571 .556 .679 .256 .315 1.597 .239 2.065 .316 1.946 2.669 .168 .908 48.591 .000 39.124 100.000
130 .687 .752 .615 .357 .293 1.543 .219 2.019 .329 2.045 2.603 .168 .917 48.453 .000 39.000 100.000
131 .538 .598 .808 .431 .313 1.706 .271 2.089 .337 1.997 2.618 .156 .909 48.375 .000 38.853 100.000
132 .508 .578 .935 .346 .287 1.550 .238 2.062 .318 1.939 2.645 .166 .919 48.491 .000 39.017 100.000
133 .696 .759 .603 .275 .331 1.747 .248 2.148 .341 2.093 2.627 .151 .920 48.303 .000 38.756 100.000
134 .545 .726 .654 .271 .341 1.827 .242 2.089 .323 1.992 2.607 .163 .904 48.411 .000 38.903 100.000
135 .480 .654 .635 .393 .313 1.664 .235 2.070 .315 2.041 2.610 .162 .918 48.496 .000 39.015 100.000
136 .532 .611 .796 .385 .285 1.829 .232 2.058 .332 1.922 2.588 .163 .904 48.415 .000 38.946 100.000
137 .535 .832 .756 .293 .342 1.694 .223 2.108 .326 1.897 2.625 .155 .918 48.400 .000 38.896 100.000
138 .495 .851 .685 .357 .346 1.705 .243 2.049 .326 2.021 2.632 .149 .904 48.376 .000 38.860 100.000
AVER: .559 .692 .717 .336 .317 1.686 .239 2.076 .326 1.989 2.623 .160 .912 48.431 .000 38.937 100.000
SDEV: .075 .107 .105 .059 .023 .101 .014 .035 .009 .063 .023 .007 .007 .080 .000 .106 .000
SERR: .024 .034 .033 .019 .007 .032 .005 .011 .003 .020 .007 .002 .002 .025 .000 .033
%RSD: 13.34 15.44 14.72 17.68 7.28 6.01 6.01 1.71 2.66 3.14 .87 4.38 .75 .17 .00 .27
STDS: 542 457 458 459 124 460 21 315 315 87 41 160 94 0 0 0
STKF: .5347 .5322 .5285 .5427 .2925 .5473 .2770 .3168 .3365 .4846 .3194 .7728 .2593 .0000 .0000 .0000
STCT: 753.7 852.7 1138.6 1390.6 2588.5 1395.9 2698.1 3702.3 5150.6 7250.3 63999.2 57600.3 22181.0 .0 .0 .0
UNKF: .0048 .0060 .0062 .0029 .0029 .0143 .0021 .0185 .0030 .0168 .0264 .0014 .0080 .0000 .0000 .0000
UNCT: 6.8 9.6 13.3 7.4 25.5 36.4 20.5 216.4 45.2 251.0 5285.8 105.8 687.4 .0 .0 .0
UNBG: 3.2 3.4 4.8 4.7 6.5 4.4 7.3 9.2 16.3 26.5 138.4 146.8 212.6 .0 .0 .0
ZCOR: 1.1579 1.1595 1.1639 1.1696 1.1002 1.1826 1.1379 1.1206 1.1055 1.1859 .9943 1.1277 1.1355 .0000 .0000 .0000
KRAW: .0090 .0112 .0116 .0053 .0098 .0261 .0076 .0585 .0088 .0346 .0826 .0018 .0310 .0000 .0000 .0000
PKBG: 3.24 3.94 3.85 2.64 4.95 9.39 3.84 24.74 3.78 10.49 39.22 1.72 4.23 .00 .00 .00
INT%: ---- -5.53 -2.53 -14.01 -.32 -.09 ---- ---- ---- ---- .00 -2.44 -.79 ---- ---- ----
TDI%: 7.866 ---- ---- ---- ---- -1.910 ---- ---- ---- ---- .022 ---- ---- ---- ---- ----
DEV%: 6.9 ---- ---- ---- ---- 2.3 ---- ---- ---- ---- .1 ---- ---- ---- ---- ----
TDIF: LOG-LIN ---- ---- ---- ---- LOG-LIN ---- ---- ---- ---- LOG-LIN ---- ---- ---- ---- ----
TDIT: 47.40 ---- ---- ---- ---- 48.40 ---- ---- ---- ---- 54.20 ---- ---- ---- ---- ----
TDII: 10.1 ---- ---- ---- ---- 40.5 ---- ---- ---- ---- 5426. ---- ---- ---- ---- ----
TDIL: 2.31 ---- ---- ---- ---- 3.70 ---- ---- ---- ---- 8.60 ---- ---- ---- ---- ----
Then the second one like this:
Un 5 SON68_10kV, Results in Elemental Weight Percents
ELEM: Na Al Si B Mg Sr Y P Zr Mo O H Li
TYPE: ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL CALC SPEC DIFF
BGDS: EXP EXP LIN EXP EXP LIN LIN LIN LIN LIN
TIME: 15.00 15.00 15.00 200.00 150.00 40.00 20.00 40.00 20.00 40.00
BEAM: 15.04 15.04 15.04 15.04 15.04 15.04 15.04 15.04 15.04 15.04
AGGR:
ELEM: Na Al Si B Mg Sr Y P Zr Mo O H Li SUM
144 6.842 2.423 21.155 4.656 .001 .324 .186 .115 2.061 1.195 51.526 .000 9.517 100.000
145 6.948 2.450 21.233 4.609 .007 .315 .175 .124 2.022 1.256 51.463 .000 9.399 100.000
146 6.925 2.524 20.990 4.697 .005 .299 .157 .123 1.941 1.248 51.555 .000 9.536 100.000
147 6.815 2.493 21.064 4.538 .003 .291 .130 .130 2.109 1.266 51.469 .000 9.694 100.000
148 7.018 2.503 20.931 4.699 .005 .319 .094 .123 2.094 1.231 51.489 .000 9.494 100.000
149 7.058 2.464 21.138 4.684 .003 .281 .164 .125 1.958 1.220 51.513 .000 9.390 100.000
150 6.908 2.487 20.987 4.723 .003 .243 .105 .128 1.998 1.210 51.616 .000 9.592 100.000
151 6.802 2.396 20.882 4.474 .003 .338 .140 .118 1.995 1.262 51.472 .000 10.117 100.000
152 6.757 2.397 21.040 4.513 .005 .293 .097 .116 2.071 1.224 51.528 .000 9.959 100.000
153 6.953 2.472 21.107 4.630 -.002 .329 .077 .119 2.005 1.236 51.517 .000 9.557 100.000
AVER: 6.903 2.461 21.053 4.622 .003 .303 .132 .122 2.025 1.235 51.515 .000 9.625 100.000
SDEV: .097 .044 .108 .087 .003 .028 .038 .005 .057 .023 .047 .000 .237 .000
SERR: .031 .014 .034 .027 .001 .009 .012 .002 .018 .007 .015 .000 .075
%RSD: 1.41 1.79 .51 1.88 76.32 9.21 28.55 4.09 2.79 1.89 .09 .00 2.47
STDS: 281 261 281 281 232 151 439 439 88 280 0 0 0
STKF: .0640 .0828 .2341 .0066 .0938 .4257 .4321 .1692 .4147 .0090 .0000 .0000 .0000
STCT: 1474.0 3324.4 9472.6 165.7 3124.8 2747.9 2986.8 3775.3 3178.5 91.1 .0 .0 .0
UNKF: .0493 .0210 .1899 .0062 .0000 .0024 .0010 .0010 .0152 .0093 .0000 .0000 .0000
UNCT: 1135.5 841.4 7684.5 155.8 .9 15.5 6.8 22.8 116.3 93.9 .0 .0 .0
UNBG: 12.9 34.0 48.8 22.2 19.8 7.2 6.4 7.1 6.8 11.1 .0 .0 .0
ZCOR: 1.3994 1.1737 1.1084 7.4651 1.2519 1.2667 1.3509 1.1945 1.3342 1.3254 .0000 .0000 .0000
KRAW: .7703 .2531 .8112 .9401 .0003 .0056 .0023 .0060 .0366 1.0309 .0000 .0000 .0000
PKBG: 90.41 25.80 159.02 8.03 1.05 3.19 2.10 4.21 18.31 9.49 .00 .00 .00
INT%: ---- ---- ---- ---- ---- ---- ---- ---- -.02 ---- ---- ---- ----
TDI%: .846 ---- ---- -1.926 ---- 1.600 ---- ---- ---- ---- ---- ---- ----
DEV%: .3 ---- ---- .3 ---- 3.1 ---- ---- ---- ---- ---- ---- ----
TDIF: LOG-LIN ---- ---- LOG-LIN ---- LOG-LIN ---- ---- ---- ---- ---- ---- ----
TDIT: 30.20 ---- ---- 213.20 ---- 55.80 ---- ---- ---- ---- ---- ---- ----
TDII: 1149. ---- ---- 177. ---- 22.6 ---- ---- ---- ---- ---- ---- ----
TDIL: 7.05 ---- ---- 5.18 ---- 3.12 ---- ---- ---- ---- ---- ---- ----
What you need to do to combine the normal intensity data and the TDI data is to select both samples and click the Combine the Selected Samples into a New Sample button as seen here:
(https://probesoftware.com/smf/oldpics/i58.tinypic.com/2dmaumq.jpg)
When the samples are combined you will see a new sample which now has the TDI data from both selected samples referenced by the new sample
as seen here:
(https://probesoftware.com/smf/oldpics/i62.tinypic.com/w14od5.jpg)
Now when you click the normal Analyze button for the newly created sample, the output will look like this:
Un 7 (Un 3 SON68_20kV, Un 5 SON68_10kV), Results in Elemental Weight Percents
ELEM: Ba La Ce Pr Cr Nd Mn Fe Ni Zn Ca Te Cs Na Al Si B Mg Sr Y P Zr Mo O H Li
TYPE: ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL CALC SPEC DIFF
BGDS: LIN LIN S-Lo LIN LIN LIN LIN LIN LIN LIN EXP LIN EXP EXP EXP LIN EXP EXP LIN LIN LIN LIN LIN
TIME: 30.00 30.00 30.00 30.00 30.00 30.00 40.00 20.00 40.00 20.00 40.00 60.00 60.00 15.00 15.00 15.00 200.00 150.00 40.00 20.00 40.00 20.00 40.00
BEAM: 15.00 15.00 15.00 15.00 15.00 15.00 15.00 15.00 15.00 15.00 15.00 15.00 15.00 15.04 15.04 15.04 15.04 15.04 15.04 15.04 15.04 15.04 15.04
AGGR:
ELEM: Ba La Ce Pr Cr Nd Mn Fe Ni Zn Ca Te Cs Na Al Si B Mg Sr Y P Zr Mo O H Li SUM
155 .601 .581 .707 .265 .326 1.651 .244 2.101 .320 1.944 2.921 .183 .962 7.321 2.502 21.436 4.468 .001 .327 .186 .115 2.057 1.184 46.078 .000 1.518 100.000
156 .723 .786 .641 .369 .303 1.595 .224 2.054 .333 2.044 2.851 .182 .972 7.446 2.532 21.523 4.416 .007 .318 .175 .124 2.018 1.244 45.862 .000 1.256 100.000
157 .567 .625 .841 .446 .323 1.763 .277 2.126 .341 1.996 2.866 .170 .963 7.432 2.611 21.287 4.498 .005 .302 .157 .122 1.938 1.236 45.869 .000 1.237 100.000
158 .535 .604 .974 .358 .297 1.602 .242 2.097 .321 1.937 2.895 .181 .973 7.301 2.576 21.352 4.347 .003 .295 .130 .130 2.105 1.254 45.912 .000 1.576 100.000
159 .733 .794 .628 .284 .342 1.806 .253 2.186 .344 2.092 2.876 .164 .975 7.537 2.590 21.229 4.498 .005 .323 .094 .123 2.091 1.219 45.724 .000 1.089 100.000
160 .574 .759 .682 .280 .353 1.889 .247 2.126 .327 1.992 2.854 .178 .958 7.568 2.548 21.433 4.487 .004 .285 .165 .125 1.955 1.208 45.863 .000 1.140 100.000
161 .506 .683 .662 .406 .323 1.721 .239 2.107 .319 2.041 2.856 .176 .972 7.403 2.571 21.277 4.531 .003 .246 .105 .128 1.995 1.199 46.064 .000 1.467 100.000
162 .560 .638 .828 .399 .295 1.890 .237 2.093 .336 1.920 2.831 .177 .957 7.294 2.478 21.175 4.282 .003 .342 .140 .118 1.992 1.250 45.839 .000 1.926 100.000
163 .564 .870 .787 .303 .354 1.751 .228 2.144 .329 1.896 2.872 .168 .971 7.245 2.478 21.330 4.314 .005 .296 .097 .116 2.067 1.212 45.874 .000 1.727 100.000
164 .522 .890 .713 .369 .358 1.762 .248 2.085 .330 2.020 2.882 .162 .958 7.460 2.557 21.403 4.432 -.002 .333 .078 .119 2.002 1.224 45.832 .000 1.265 100.000
AVER: .589 .723 .746 .348 .327 1.743 .244 2.112 .330 1.988 2.870 .174 .966 7.401 2.544 21.345 4.427 .004 .307 .133 .122 2.022 1.223 45.892 .000 1.420 100.000
SDEV: .079 .112 .110 .062 .024 .105 .015 .036 .009 .063 .025 .008 .007 .108 .046 .106 .086 .003 .028 .038 .005 .056 .023 .106 .000 .271 .000
SERR: .025 .035 .035 .019 .008 .033 .005 .011 .003 .020 .008 .002 .002 .034 .015 .034 .027 .001 .009 .012 .002 .018 .007 .034 .000 .086
%RSD: 13.35 15.45 14.71 17.71 7.29 6.00 6.02 1.71 2.65 3.15 .88 4.38 .75 1.46 1.82 .50 1.95 76.34 9.21 28.54 4.09 2.79 1.88 .23 .00 19.06
STDS: 542 457 458 459 124 460 21 315 315 87 41 160 94 281 261 281 281 232 151 439 439 88 280 0 0 0
STKF: .5347 .5316 .5280 .5422 .2922 .5467 .2766 .3168 .3365 .4843 .3190 .7728 .2588 .0642 .0830 .2346 .0066 .0941 .4272 .4328 .1695 .4154 .0091 .0000 .0000 .0000
STCT: 753.7 852.7 1138.6 1390.6 2588.5 1395.9 2698.1 3702.3 5150.6 7250.3 63999.2 57600.3 22181.0 1474.0 3324.4 9472.6 165.7 3124.8 2747.9 2986.8 3775.3 3178.5 91.1 .0 .0 .0
UNKF: .0048 .0060 .0061 .0029 .0029 .0142 .0021 .0185 .0030 .0168 .0263 .0014 .0080 .0494 .0210 .1903 .0062 .0000 .0024 .0010 .0010 .0152 .0093 .0000 .0000 .0000
UNCT: 6.8 9.6 13.3 7.4 25.5 36.4 20.5 216.4 45.2 251.0 5285.8 105.8 687.3 1135.5 841.4 7684.5 155.8 .9 15.5 6.8 22.8 116.3 93.9 .0 .0 .0
UNBG: 3.2 3.4 4.8 4.7 6.5 4.4 7.3 9.2 16.3 26.5 138.4 146.8 212.6 12.9 34.0 48.8 22.2 19.8 7.2 6.4 7.1 6.8 11.1 .0 .0 .0
ZCOR: 1.2194 1.2141 1.2137 1.2133 1.1386 1.2237 1.1629 1.1402 1.1180 1.1858 1.0896 1.2260 1.2048 1.4974 1.2109 1.1216 7.1547 1.3132 1.2769 1.3527 1.1921 1.3298 1.3104 .0000 .0000 .0000
KRAW: .0090 .0112 .0116 .0053 .0098 .0261 .0076 .0585 .0088 .0346 .0826 .0018 .0310 .7703 .2531 .8112 .9401 .0003 .0056 .0023 .0060 .0366 1.0309 .0000 .0000 .0000
PKBG: 3.24 3.93 3.84 2.64 4.95 9.39 3.84 24.74 3.78 10.49 39.22 1.72 4.23 90.41 25.80 159.02 8.03 1.05 3.19 2.10 4.21 18.31 9.49 .00 .00 .00
INT%: ---- -5.60 -2.56 -14.14 -.32 -.10 ---- ---- ---- ---- .00 -2.41 -.80 ---- ---- ---- ---- ---- ---- ---- ---- -.02 ---- ---- ---- ----
TDI%: 7.866 ---- ---- ---- ---- -1.910 ---- ---- ---- ---- .022 ---- ---- .846 ---- ---- -1.926 ---- 1.600 ---- ---- ---- ---- ---- ---- ----
DEV%: 6.9 ---- ---- ---- ---- 2.3 ---- ---- ---- ---- .1 ---- ---- .3 ---- ---- .3 ---- 3.1 ---- ---- ---- ---- ---- ---- ----
TDIF: LOG-LIN ---- ---- ---- ---- LOG-LIN ---- ---- ---- ---- LOG-LIN ---- ---- LOG-LIN ---- ---- LOG-LIN ---- LOG-LIN ---- ---- ---- ---- ---- ---- ----
TDIT: 47.40 ---- ---- ---- ---- 48.40 ---- ---- ---- ---- 54.20 ---- ---- 30.20 ---- ---- 213.20 ---- 55.80 ---- ---- ---- ---- ---- ---- ----
TDII: 10.1 ---- ---- ---- ---- 40.5 ---- ---- ---- ---- 5426. ---- ---- 1149. ---- ---- 177. ---- 22.6 ---- ---- ---- ---- ---- ---- ----
TDIL: 2.31 ---- ---- ---- ---- 3.70 ---- ---- ---- ---- 8.60 ---- ---- 7.05 ---- ---- 5.18 ---- 3.12 ---- ---- ---- ---- ---- ---- ----
-
Bumping this topic forward in case some of you missed this cool new absorbed current acquisition capability in the TDI feature...
http://probesoftware.com/smf/index.php?topic=11.msg2499;topicseen#msg2499
-
Ok, I have been playing with the "Assigned TDI" function and ran into some problems. I would like to double check that I am not blind or am missing an important point when it comes to the Assigned TDI function (although I am thinking it is more that the "Assigned TDI" is the red-headed step child to the "Self TDI" and it hasn't come up yet).
1. I can only see "Self TDI" but not "Assigned TDI" data under "Run" -> "Display Time Dependent (TDI)...."
2. I can only see the TDI data for the first batch of elements under "Standard Assignments" - Elements - Use TDI Assigned Calibration Correction, even though it acquired data for all elements.
3. I also cannot assign then the TDI calibration correction to the second (third, fourth..) batch of elements to a sample acquired by "normal acquisition" even though I have data for all of them (see above).
Thoughts? Thanks!
-
Ok, I have been playing with the "Assigned TDI" function and ran into some problems. I would like to double check that I am not blind or am missing an important point when it comes to the Assigned TDI function (although I am thinking it is more that the "Assigned TDI" is the red-headed step child to the "Self TDI" and it hasn't come up yet).
1. I can only see "Self TDI" but not "Assigned TDI" data under "Run" -> "Display Time Dependent (TDI)...."
2. I can only see the TDI data for the first batch of elements under "Standard Assignments" - Elements - Use TDI Assigned Calibration Correction, even though it acquired data for all elements.
3. I also cannot assign then the TDI calibration correction to the second (third, fourth..) batch of elements to a sample acquired by "normal acquisition" even though I have data for all of them (see above).
Thoughts? Thanks!
Hi Anette,
First- don't use the assigned TDI feature. ??? But seriously, I'm curious why you are using the assigned TDI feature because it's difficult for me to imagine a situation in which the assigned TDI would be more useful than the self TDI. Certainly the self TDI is more accurate and easier to use! The only time I can think of where the assigned TDI might be useful is when one wants to be sure that the line to line compositional variation in a sample is not due to the self TDI statistics...
Second- it's not meant to be used how I suspect you are trying to use it. For example, to see the assigned TDI data, just use the Raw Data button in the Analyze! window for the sample that is the TDI assigned calibration curve. Each data point/line in the assigned TDI sample is one TDI calibration point.
Third- call me and let's chat about it. I almost never use this feature and haven't in a long time so it might not be functioning exactly correctly.
john
Edit by John: I fixed the disabled control for assigned TDI samples with subsequently acquired elements on each spectrometer (order > 1), that you described above. Ready to download now.
-
In addition, I should mention that the assigned TDI is also useful when you need to perform a TDI correction on an element that is *not* acquired as the first element on a spectrometer. Since the self TDI can only be performed on the first element on a spectrometer...
-
I hope this is the right place...
In the recent (2016) MAS abstracts from Madison, I noticed an abstract by Stephen Kuehn on using TDI along with combined WDS-EDXA methods to analyze glasses using a reduced beam diameter.
I've tried something similar to this (but using a broad beam) to simplify methods (single beam condition) for complex F-bearing, borosilicate rhyolitic glasses, doing Al and Si by EDXA, but hit a snag. At "Analyze" the software tells me that there is no TDI data available for the elements done by EDXA. So, how can both WDS and EDXA data be acquired simultaneously while enabling TDI correction? Is there a way to turn off the TDI feature only for the EDXA elements, or does it work if the total EDXA count time is less than the first increment of TDI for the WDS? Doing things consecutively (e.g., EDXA followed by WDS) won't work for hydrous things because a large fraction of alkali migration (10-30% for simple rhyolitic compositions saturated in H2O at 2 kbar) occurs during the first 1-3 seconds of irradiation.
-
I hope this is the right place...
In the recent (2016) MAS abstracts from Madison, I noticed an abstract by Stephen Kuehn on using TDI along with combined WDS-EDXA methods to analyze glasses using a reduced beam diameter.
I've tried something similar to this (but using a broad beam) to simplify methods (single beam condition) for complex F-bearing, borosilicate rhyolitic glasses, doing Al and Si by EDXA, but hit a snag. At "Analyze" the software tells me that there is no TDI data available for the elements done by EDXA. So, how can both WDS and EDXA data be acquired simultaneously while enabling TDI correction? Is there a way to turn off the TDI feature only for the EDXA elements, or does it work if the total EDXA count time is less than the first increment of TDI for the WDS? Doing things consecutively (e.g., EDXA followed by WDS) won't work for hydrous things because a large fraction of alkali migration (10-30% for simple rhyolitic compositions saturated in H2O at 2 kbar) occurs during the first 1-3 seconds of irradiation.
Hi George,
There is no TDI correction for EDS elements at this time. Basically one would have to acquire individual EDS spectra for each "self" TDI interval. I'm sure "John" will get around to implementing this at some point!
Interestingly, this might already work using the "assigned" TDI method that Anette mentions above since each data point (data line) with the "assigned" TDI method is actually a TDI point. And since each data point in PFE gets its own EDS spectra...
Try the assigned TDI with EDS elements and let us know what you find out...
-
John
Tell me that I am wrong, but as best I can figure it out, you output to the LOG WINDOW _ONLY_ TDI corrected counts when an actual quant analysis is performed.
We are using TDI to evaluate optimal 'minimal beam impact on hydrous sheet silicates with FE electron probe' with different beam sizes AS WELL as impact of acquiring scanned (BSE) images, looking only at raw count (P+B) vs time date.
We were applying various curves and seeing NO change in the RAW DATA output (we are NOT setting up standards, as this is an experiment on a given reference material and we don't need to acquire a standard), regardless of whether we turn TDI on or off, or change the curvature.
We see the Y intercept is shown, which provides the value we need.
But it can be confusing, if someone is only acquiring raw counts. You might want to add a comment in the TDI plot windows that RAW DATA shown in LOG WINDOW is only the TDI-uncorrected data.
If this is incorrect, please explain.
Thanks.
-
But it can be confusing, if someone is only acquiring raw counts. You might want to add a comment in the TDI plot windows that RAW DATA shown in LOG WINDOW is only the TDI-uncorrected data.
Hi John,
That is correct. Raw data is raw data (and always will be, per omnia secula seculorum). The TDI correction is applied during the matrix correction, along with the background correction, interference correction and all other corrections.
john
-
I recently discussed the new TDI scanning method on the NIST SRM K-1718 beam sensitive material here:
http://probesoftware.com/smf/index.php?topic=912.msg5904#msg5904
However, the point analyses of this material are also worth looking at. This material has the following composition as specified by NIST:
ELEM: Na Fe Ca Si O SUM
ELWT: 14.837 10.491 3.574 28.048 43.050 100.000
OXWT: 20.000 13.497 5.000 60.005 1.498 100.000
ATWT: 13.994 4.073 1.933 21.655 58.344 100.000
Here are TDI plots of log intensities for Na and Si, first with a 20 nA focused beam:
(https://probesoftware.com/smf/gallery/395_20_04_17_5_50_04.png)
(https://probesoftware.com/smf/gallery/395_20_04_17_5_50_24.png)
I had to utilize the double exponential fit to get even a halfway decent composition as seen here:
15 keV, 20 nA, 0 um, 1 sec intervals:
ELEM: Na Fe Ca Si O SUM
172 14.331 11.200 4.035 29.551 43.476 102.593
173 12.957 11.087 4.337 29.952 43.542 101.874
174 12.794 11.243 3.993 29.676 43.079 100.785
175 16.627 11.606 4.224 30.640 45.706 108.802
AVER: 14.177 11.284 4.147 29.955 43.951 103.513
SDEV: 1.773 .224 .161 .486 1.188 3.603
TDI%: 928.684 -6.004 .202 -13.391 ---
DEV%: 3.6 .6 1.0 .2 ---
The averages aren't all that bad considering the Na extrapolation is over 900% (!), and the Si extrapolation is over 13 % (negative).
And here again, but with a 20 nA, 20 um defocused beam:
(https://probesoftware.com/smf/gallery/395_20_04_17_5_50_56.png)
(https://probesoftware.com/smf/gallery/395_20_04_17_5_51_13.png)
Again, all plotted in log intensity space. I find it interesting that with a 20 um beam, the Na trend, instead of the normal exponential, hyper-exponential or double exponential trends, we instead see a "hypo-exponential" trend. That is, a little less than a normal exponential... and here are the quant results:
15 keV, 20 nA, 20 um, 1 sec intervals:
ELEM: Na Fe Ca Si O SUM
208 14.643 10.321 3.802 28.711 42.282 99.758
209 14.711 10.788 3.838 29.091 42.887 101.315
210 15.123 10.710 3.728 28.991 42.851 101.404
211 13.979 10.394 3.872 28.746 42.140 99.130
AVER: 14.614 10.553 3.810 28.885 42.540 100.402
SDEV: .474 .230 .061 .186 .385 1.136
TDI%: 53.503 -3.738 -2.765 -4.833 ---
DEV%: .4 .7 1.3 .2 ---
The defocused beam analyses are, not surprisingly, quite a bit better and the TDI corrections much more reasonable for this very *unreasonable* material!. ;)
john
-
Hi,
I have a controversial suggestion - to see what you think. Currently TDI only applies to first row elements. This restricts it to the first element on each of the spectromters. I'd like to suggest that it could be used for second row elements - if it was done carefully checking that the intensity was a linear drop of with time - then it can be done for the second row elements. A case were it might be useful is volcanic glass with 2 TAP, 2 PET, and 2 LIF. Where Al is measured after Si (i.e. can't measure Si, Al and Na in first row). Currently you have to make sure its stable for the second row Al, so having to make sure Al is linear drop off is not much harder?
Ben
-
Hi,
I have a controversial suggestion - to see what you think. Currently TDI only applies to first row elements. This restricts it to the first element on each of the spectromters. I'd like to suggest that it could be used for second row elements - if it was done carefully checking that the intensity was a linear drop of with time - then it can be done for the second row elements. A case were it might be useful is volcanic glass with 2 TAP, 2 PET, and 2 LIF. Where Al is measured after Si (i.e. can't measure Si, Al and Na in first row). Currently you have to make sure its stable for the second row Al, so having to make sure Al is linear drop off is not much harder?
Ben
Hi Ben,
The only reason I don't allow using TDI on subsequent pass elements (those elements other than the first element on each spectrometer), is simply because I suspect it will simply not be accurate enough when extrapolating that far to zero time.
One way to test whether we can make this far an extrapolation, would be to set a long "incubation" interval in the Acquisition Options dialog, say 40 secs or so, thus exposing the sample to the beam for 40 secs before the TDI measurement starts. Then we can see how accurate these extrapolations are.
The problem is, I'm sure that one can find situations where this long extrapolation will work, when utilizing gentle enough conditions. But there will also be beam/sample conditions that will yield an inaccurate extrapolation.
The problem is, unlike the first element in the spectrometer pass, if there is no data for the first 40 secs or so, how will one know that the extrapolation is inaccurate?
I'm willing to discuss it, but as you say, it is "controversial"!
john
-
Since beam sensitive samples are being discussed in the Cs standard topic by Brian Joy and I just had a student run some very beam sensitive rhyolite glasses earlier this week, I thought we might revisit the the Time Dependent Intensity (TDI) correction feature since the student got some excellent results in a very hydrous alkali glass that entailed some very large corrections.
This was apparently a Bishop Tuff rhyolite pumice which they suspected from FTIR analysis would have around 5 wt% H2O. So we tuned up the instrument for 15 keV, 15 nA and used a 5 um beam (for the Mg, Ca, Cl, Ti and F traces we used a 50 nA beam). Normally we would use a more defocussed 10 um beam to keep the TDI correction a little more reasonable, but the glass bubble walls were very thin, and as they say "necessity is a mother". :)
Here is the last sample she ran, and note the average correction percent and average variation percent (in red):
Un 55 unknown 147_16, Results in Elemental Weight Percents
ELEM: Na Si K Al Fe Mg Ca Cl Ti F O H P Mn S
TYPE: ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL ANAL CALC DIFF SPEC SPEC SPEC
BGDS: MAN MAN LIN MAN MAN MAN MAN LIN LIN LIN
TIME: 40.00 40.00 40.00 40.00 40.00 165.00 150.00 120.00 120.00 120.00 --- --- --- --- ---
BEAM: 14.91 14.91 14.91 14.91 14.91 50.73 50.73 50.73 50.73 50.73 --- --- --- --- ---
ELEM: Na Si K Al Fe Mg Ca Cl Ti F O H P Mn S SUM
188 3.108 34.107 3.788 6.193 .460 .018 .294 .096 .021 .041 51.273 .601 .000 .000 .000 100.000
189 3.378 33.632 3.838 6.347 .486 .018 .290 .092 .026 .044 51.218 .631 .000 .000 .000 100.000
190 3.415 33.822 3.634 6.267 .585 .017 .289 .085 .033 .061 51.185 .608 .000 .000 .000 100.000
AVER: 3.300 33.854 3.753 6.269 .510 .018 .291 .091 .027 .049 51.225 .614 .000 .000 .000 100.000
SDEV: .168 .239 .106 .077 .066 .000 .003 .005 .006 .010 .045 .015 .000 .000 .000 .000
SERR: .097 .138 .061 .045 .038 .000 .002 .003 .004 .006 .026 .009 .000 .000 .000
%RSD: 5.08 .71 2.83 1.23 12.94 2.16 .92 6.01 23.15 21.19 .09 2.52 .00 .00 .00
STDS: 336 162 374 336 162 162 162 285 22 835 --- --- --- --- ---
STKF: .0735 .2018 .1132 .1332 .0950 .0568 .1027 .0602 .5547 .1715 --- --- --- --- ---
STCT: 64.51 244.54 138.78 220.67 20.49 70.15 188.59 61.70 42.06 23.55 --- --- --- --- ---
UNKF: .0179 .2768 .0324 .0488 .0042 .0001 .0026 .0007 .0002 .0001 --- --- --- --- ---
UNCT: 15.72 335.41 39.70 80.80 .91 .15 4.75 .74 .02 .02 --- --- --- --- ---
UNBG: .33 .31 .94 .85 .20 .48 .93 .33 .05 .05 --- --- --- --- ---
ZCOR: 1.8421 1.2230 1.1593 1.2854 1.2090 1.4697 1.1257 1.2548 1.2064 4.1458 --- --- --- --- ---
KRAW: .2437 1.3716 .2860 .3662 .0444 .0021 .0252 .0120 .0004 .0007 --- --- --- --- ---
PKBG: 48.89 1068.36 43.46 96.38 5.47 1.31 6.13 3.26 1.38 1.35 --- --- --- --- ---
INT%: ---- ---- ---- ---- ---- ---- ---- ---- ---- -.86 --- --- --- --- ---
TDI%: 282.195 -2.408 35.459 -2.496 5.719 ---- ---- ---- ---- ---- --- --- --- --- ---
DEV%: 5.4 .2 .9 .4 1895.2 ---- ---- ---- ---- ---- --- --- --- --- ---
TDIF: HYP-EXP LOG-LIN LOG-LIN LOG-LIN LOG-LIN ---- ---- ---- ---- ---- --- --- --- --- ---
TDIT: 101.33 102.00 103.67 104.67 104.33 ---- ---- ---- ---- ---- --- --- --- --- ---
TDII: 12.3 335. 40.5 81.5 1.11 ---- ---- ---- ---- ---- --- --- --- --- ---
TDIL: 2.51 5.81 3.70 4.40 .106 ---- ---- ---- ---- ---- --- --- --- --- ---
Un 55 unknown 147_16, Results in Oxide Weight Percents
ELEM: Na2O SiO2 K2O Al2O3 FeO MgO CaO Cl TiO2 F O H2O P2O5 MnO SO3 SUM
188 4.189 72.966 4.563 11.702 .592 .030 .412 .096 .035 .041 .000 5.375 .000 .000 .000 100.000
189 4.554 71.952 4.623 11.993 .625 .029 .406 .092 .043 .044 .000 5.639 .000 .000 .000 100.000
190 4.603 72.357 4.377 11.841 .752 .029 .404 .085 .056 .061 .000 5.436 .000 .000 .000 100.000
AVER: 4.449 72.425 4.521 11.845 .656 .029 .407 .091 .044 .049 .000 5.483 .000 .000 .000 100.000
SDEV: .226 .511 .128 .146 .085 .001 .004 .005 .010 .010 .000 .138 .000 .000 .000 .000
SERR: .131 .295 .074 .084 .049 .000 .002 .003 .006 .006 .000 .080 .000 .000 .000
%RSD: 5.08 .71 2.83 1.23 12.94 2.16 .92 6.01 23.15 21.19 .00 2.52 .00 .00 .00
STDS: 336 162 374 336 162 162 162 285 22 835 --- --- --- --- ---
Note that the H2O by difference is close to 5% which was very nice to see. However, that is in spite of the Na TDI correction is almost 300%, which means that we lost 2/3 of our intensity during the count integration! The TDI plot for Na looks like this:
(https://probesoftware.com/smf/gallery/395_20_06_18_9_18_52.png)
We could probably get a little better accuracy by using a slightly shorter integration time. Here also is the plot for K which was a 35% correction:
(https://probesoftware.com/smf/gallery/395_20_06_18_9_19_29.png)
and this for Si and Al:
(https://probesoftware.com/smf/gallery/395_20_06_18_9_19_08.png)
(https://probesoftware.com/smf/gallery/395_20_06_18_9_19_48.png)
and both are statistically significant corrections if you will compare the TDI%: and DEV%: values for Si and Al. However, for an element such as Fe, there is no TDI effect, as seen in both the TDI%: and DEV%: values and also from the plot here:
(https://probesoftware.com/smf/gallery/395_20_06_18_9_20_02.png)
So if you are analyzing hydrous alkali glasses (even with a defocused beam) I hope you are turning on the TDI correction feature!
-
Hello,
We run a lot of hydrous rhyolitic glass, and this has encouraged me to look at zeolites in more detail.
However, I noticed that the time-scale for the self-TDI is a bit funny.
Our initial setup is 20 s on peak, with 5 TDI intervals, so the spacing should be every 4 seconds (right?).
A JPG of the screen capture of the TDI data is attached.
The text from the associated DAT file follows:
"Elapsed Time (10 keV, 10 nA,5 um, 4 sec)" "Na ka Intensity (cps/1nA)"
3.00000 118.593
10.0000 113.562
16.0000 114.460
23.0000 107.661
30.0000 102.197
It is not clear to me why the intervals are not an even 4 seconds apart....
Thanks,
Andrew
-
Hi Andrew,
It's because the program is recording the elapsed *real time*, not the specified/calculated time.
Due to instrument/software latencies and other delays, we have to use the actual elapsed time to get an accurate TDI slope.
john
-
Ok, thanks!
-
Dave Adams (USGS Denver) recently sent me an MDB file (probe run file) that he was having a problem with and in sorting that out we noticed (because his run had over 500 unknown samples in it!), that loading the Standard Assignments dialog was taking longer than one would like.
The problem turned out to be due to the fact that the app scans all unknown samples in the current run when loading the Standard Assignments dialog, in order to list all unknown samples that could be utilized in the quantitative blank correction for the selected element (matching element, x-ray, spectrometer and Bragg crystal):
http://probesoftware.com/smf/index.php?topic=454.msg6694#msg6694
So we optimized the code and now that dialog loads about 5 to 8 times faster, which is nice when one has a very large run like Dave had. Update Probe for EPMA from the Help menu and all will be good.
-
Hi,
Is it possible to export the errors for each TDI point - I'm using Output - Save TDI
Thanks
Ben
-
Hi,
Is it possible to export the errors for each TDI point - I'm using Output - Save TDI
Thanks
Ben
Hi Ben,
When you say "errors for each TDI point", do you mean the % TDI correction and the % TDI variance for each data point in a sample?
john
-
Hi John,
Sorry I should have made myself clear, I mean the error bars as shown on the figure below
(https://probesoftware.com/smf/gallery/453_29_11_18_2_22_03.png)
Thanks
Ben
-
Oh right. Doing that will disturb the format for those already depending on the existing output, so I can do that but I hope no one minds...
john
-
Hi John,
Sorry I should have made myself clear, I mean the error bars as shown on the figure below
(https://probesoftware.com/smf/gallery/453_29_11_18_2_22_03.png)
Thanks
Ben
Hi Ben,
I was able to add output of the TDI intensity one sigma error values from the Output menu as seen here:
(https://probesoftware.com/smf/gallery/1_01_12_18_9_01_02.png)
Let me know if this works for you.
john
-
Thanks John, this works well
Ben
-
Hi John,
How do you calculate the error (% rel) for analyses using TDI, do you simply calculate the counting statistics error, or do you calculate the standard error for the intercept for a linear regression
Thanks
Ben
-
Hi John,
How do you calculate the error (% rel) for analyses using TDI, do you simply calculate the counting statistics error, or do you calculate the standard error for the intercept for a linear regression
Thanks
Ben
In the TDI output to file? It's counting statistics calculated the same way for the error bars in the TDI plots, but always 1 sigma.
-
Sorry for the slow reply. No I meant in the output of results - (Save analysis output, or save user specified format output)
Thanks
Ben
-
Yes, they are all 1 sigma counting statistic errors.
-
Hi John.
I'm not sure you are calculating the uncertainty for data collected with the TDI correction switched on. Are you taking in to account the uncertainty of each point on the TDI curve and propagating uncertainty through the extrapolation to time=0 seconds? We ran 30 points on a beam sensitive glass and compared the standard deviation to the uncertainty reported by the software. With TDI off the standard deviations compare very well to the reported "% ERR". The absolute uncertainties for these analyses with TDI switched off are shown below (they agree quite nicely):
TDI off ZnO Al2O3 SiO2
Standard deviation 0.09 0.07 0.16
Reported "% ERR" 0.09 0.05 0.18
With the TDI switched on the reported standard deviation values are quite a bit larger than the %ERR as expected if the uncertainty on each TDI point isn't propagated through the extrapolation to time zero:
TDI on ZnO Al2O3 SiO2
Standard deviation 0.46 0.25 0.62
Reported "% ERR" 0.09 0.05 0.18
In this data set we used the log-quadratic fit to the data. The uncertainty calculated by the software might be misleading if I have this right.
-
Hi Ben,
Which TDI output are we discussing here? The Analyze! window/log window output, the Output | Save Time Dependent Intensities menu, or the Output | User Specified output menu, or some other place?
john
-
I used the user specified output and selected relative error.
-
Hi Ben,
I don't see relative error in that dialog. Did you mean sample standard deviation and/or sample standard error?
-
"analytical errors in relative percents" in the user specified format output.
-
Hi Ben,
Ah, OK.
So as you know, these are the analytical sensitivities calculated using the method of Love/Scott, as seen here from the PFE Reference manual:
(https://probesoftware.com/smf/gallery/1_15_05_19_11_32_50.png)
These analytical sensitivity errors are basically a sort of peak to background estimation which according to Love/Scott are predictive as to knowing that two numbers are statistically different from each other, as opposed to simply variances in the counting statistics.
In our implementation of this equation we utilize any corrections that have been applied to the raw data that changes the net intensities, in order to be somewhat more accurate in the analytical sensitivity estimates. This includes changes to the net intensities due to the spectral interference, APF, MAN and TDI corrections (and probably a few other corrections).
Now if I pick a (very) beam sensitive sample, specifically the NIST K-375 glass, and output the results *without* the TDI correction I get these results:
(https://probesoftware.com/smf/gallery/1_15_05_19_11_35_20.png)
Note that the Na and Si average analytical sensitivity errors are 1.550108 and 0.463727 respectively. Now with the TDI correction turned on I get:
(https://probesoftware.com/smf/gallery/1_15_05_19_11_35_55.png)
Now note that the average analytical sensitivity errors are now 0.724499 and 0.474985 respectively. They are smaller for Na because due to the slope of the TDI corrections, so the net intensity was increased and the analytical sensitivity improved, because the peak to bgd improved. And for Si, the net intensities were instead decreased, because of the different slope for the Si TDI corrections. That is, due to the TDI corrections, the Na P/B increased (a lot), but the Si P/B decreased (slightly).
So I cannot explain why you are not seeing much of a change in your analytical sensitivities from the TDI corrections, unless your TDI corrections are very small.
You asked about the TDI fit deviation and the answer is that the variance due to the regression scatter in the TDI plot is not applied in this calculation. There are however several different options for outputing the TDI correction magnitude and fit variance as seen here:
(https://probesoftware.com/smf/gallery/1_15_05_19_11_57_55.png)
I would have to think if there is a way the TDI fit variance could be applied to the analytical sensitivity calculation, but in the meantime you might want to look at the output from the Output | Save Time Dependent Intensities menu. This output option saves a lot of parameters utilized in the TDI corrections to a tab delimited file. I know several users have leveraged this information in their own TDI studies.
By the way, this variation in the TDI correction from point to point is exactly why the "assigned TDI" (as opposed to the "self TDI") correction was created. Basically Ian Carmichael at UC Berkeley wanted a TDI correction that utilized a constant slope TDI correction for each data point in a sample, so that he could be sure that the variation between data points was due to the composition changing, as opposed to the statistics bouncing around from one data point to the next.
The reason almost nobody uses the "assigned" TDI correction is that due to all kinds of different ion migration physics, even a fairly homogeneous sample can show statistically significant variation from one acquisition to the next.
https://probesoftware.com/smf/index.php?topic=116.msg454#msg454
john
-
I would sum up the above by noting that the analytical sensitivity calculation by Love/Scott is essentially a description of the P/B ratio for an individual data point, which is affected by the slopes of the TDI corrections for each element, since the TDI correction can change the net intensity, but not the bgd intensity. So the TDI correction changes the analytical sensitivity of each data point and is calculated for each data point separately.
While the standard deviation is a description of the point to point variation for all data points in a sample. These individual data points are affected by the TDI correction of each point, but not in a systematic manner. That is, the TDI correction might amplify the statistical variance in the TDI curves if the variation in the TDI calibration curves are essentially random variation, but the TDI correction might also not change the variance of the data points much at all, if the TDI curves are very consistent from point to point.
Hope that helps.
-
I've been measuring Na intensity loss from silicate glasses with self TDI correction. And I have one question how the final Na X-ray intensities were calculated.
"Note that the linear TDI correction utilizes only the slope of the TDI fit in log space. However the “hyperexponential” TDI correction utilizes the actual intercept of the 2nd order quadratic fit to the TDI data."
This is what I read from the User Reference Manual and I understood that extrapolated y-intercept at t=0 was finally used for matrix correction calculation when I use Quadratic (Hyper-Exponential) fitting. However, after I Analyze TDI corrected sample, I found out that X-ray counts of Na at "UNCT" row and "TDII" row are quite different.
(https://probesoftware.com/smf/gallery/1632_22_01_20_5_46_02.png)
Could you explain how the final intensity at "UNCT" row are calculated from the y-intercept intensity at "TDII" row??
-
Hi Hwayoung,
You are exactly correct! I had not updated the reference manual after we modified the code a couple of years ago to handle using duplicate elements (aggregate feature) with the TDI correction. Basically one can't average quadratic slopes! So now the reference manual says:
Note that the linear TDI correction utilizes only the slope of the TDI fit in log space. However the “hyper-exponential” TDI correction utilizes a 2nd order quadratic fit to the TDI data. While the log-log (double exponential) fit utilizes only the slope fit term similar to the log-linear fit, but with a LOG(elapsed-time) term.
Here is the source code for the calculation:
atemp! = (sample(1).VolCountTimesStop(linerow%, chan%) - sample(1).VolCountTimesStart(linerow%, chan%)) * SECPERDAY#
' Calculate log linear TDI fit
If sample(1).VolatileFitTypes%(chan%) = 0 Then
voluncts! = Log(uncts!) - sample(1).VolatileFitSlopes!(chan%) * (atemp! / 2#)
' Calculate hyper exponential TDI fit (quadratic)
ElseIf sample(1).VolatileFitTypes%(chan%) = 1 Then
voluncts! = Log(uncts!) - sample(1).VolatileFitSlopes!(chan%) * (atemp! / 2#) - sample(1).VolatileFitCurvatures!(chan%) * (atemp! / 2#) ^ 2
' Calculate double exponential TDI fit (logarithmic)
ElseIf sample(1).VolatileFitTypes%(chan%) = 2 Then
voluncts! = Log(uncts!) - sample(1).VolatileFitSlopes!(chan%) * Log(atemp! / 2#)
End If
You can get the updated reference manual by updating Probe for EPMA from the Help menu as usual. See the latest changes here:
https://probesoftware.com/smf/index.php?topic=40.0
Note that you are attributed in the version.txt file! Please let me know if you have any further questions.
-
I'm working with a very beam sensitive mineral and I am using TDI corrections, especially for Na and Al. For most of my analyses the log-linear or quadratic-linear TDI corrections work very well and there are only minor differences (+/- 1) between the Linear-Linear Y intercept and the Log-Linear or Log-Quadratic Y intercept. However, in some of my especially Na-rich analyses there is a significant difference between the Y-intercept on the Linear-Linear chart and the Y-intercept on the Log-Linear chart, with the resulting Log-Linear correction (I believe) overestimating Na.
In my example, the Y intercept for Linear-Linear is 53, while the Y intercept for Log-Linear is 59
Is there any way to add an option to use a Linear-Linear correction or as an added question is there any way to ask the software use Point 1 as the only analytical point if you have an odd analysis with points producing a weird model?
Thank you for your time.
-
Hi Andrew,
I'm not sure what you mean by linear-linear. Do you mean that the y axis is a linear scale and the fit is also linear? All the TDI equations are based on log intensities (someday I hope you'll see a paper from us on the details of all this!).
Anyway, better to plot these up in the Standard Assignments dialog as you can see multiple data points at a time.
And yes you can weight the initial TDI points using the Analytical | Analysis Options menu dialog as seen here:
(https://probesoftware.com/smf/oldpics/i43.tinypic.com/2pt3pk1.jpg)
The full post discussing this TDI fit feature is here:
https://probesoftware.com/smf/index.php?topic=116.msg461#msg461
-
Thank you for the tip on weighting the initial TDI points. I've been playing around with that today and seeing some differences.
In the Display Time Dependent Intensity (TDI) and Alternating On/Off Peaks Window you are able to plot 6 different relationships that calculate 6 different TDI intercepts
Linear Intensity - Linear model
Linear Intensity - Quadratic model
Linear Intensity - Log model
Log Intensity - Linear model
Log Intensity - Quadratic model
Log Intensity - Log model
However, we are only able to apply 3 of the models to the analysis. Would it be possible to use the other 3 models as well, since the TDI intercepts are already calculated in the software?
I'm looking at a sample with the following:
Log intensity - Linear model, TDI intercept = 59
Linear intensity - Linear model, TDI intercept = 53
I'm estimating the difference between these two linear models as close to 1 weight percent in this instance.
-
Hi Andrew,
I find it strange that your beam sensitive samples do not exhibit log changes in intensity. As far as I know this has not been previously reported.
It would be significant work to implement three additional models, but I will look into it when I get a chance.
Thinking about it more, you might get a better log fit using a higher beam current. Also better statistics!
-
Hi Andrew,
I looked more closely at your plots in the post above and it appears that you are getting slightly better fits using the log intensity plot, though with a very slightly negative curvature.
And also now that I think about it again I have seen such "negative" curvatures for TDI plots, which does indicates that these trends are slightly more linear than a linear log fit. But again I can't think of a reason why you wouldn't just use the log intensity plots since it is a better fit.
-
One way I've gone about looking at how the models fit is to look at a chart looking at the following (Na counts at elapsed time / maximum Na counts modeled/measured for the point):
At time 0 lets say the model calculates the cps value to be 100 cps/na. At time 10s Na measured was as 80 cps, at time 20s Na measured was 60 cps
In the chart I would plot time 0 as 100% (100/100), at time 10 I would plot 80% (80/100), and at time 20 I would plot 60% (60/100). This allows me to compare how multiple points behave without (*hopefully*) being too influenced by variations in total Na content.
I ran 41 points on my samples (same mineral, just a few different grains)
When I plot the value of Measured/Modeled Na cps/na / Maximum Na cps for a point vs Elapsed time, it looks like the Linear - Linear model does the best job matching how Na behaves during analysis in this mineral. Do you think this is a good way of looking at it?
Thanks again for all of your help with this. It's been a tricky analysis to process.
-
Hi Andrew,
Interesting stuff. I'm interested in this mineral, what is it?
But since the TDI fit is applied on a per point basis, I think looking at the statistics for each single point is a better way to evaluate this.
john
-
John,
It's alunite/natroalunite - (K,Na)Al3(SO4)2(OH)6
So you would recommend evaluating the models on a point by point basis rather than trying to be consistent with the model used?
Thanks again.
Andrew
-
So you would recommend evaluating the models on a point by point basis rather than trying to be consistent with the model used?
Hi Andrew,
I think the model you use to evaluate the fit should be evaluated on a point by point basis since that is how the TDI correction is applied during the matrix iteration.
In your original examples it looked to me (based on the Relative Deviation % displayed) that the log-linear fit gave the smallest avg deviation.
john
-
This may have been pointed out earlier, but:
The TDI intensities can be saved in Excel format, and then evaluated in Excel.
An example of Na intensities for a point in obsidian (15 kV, 6 nA, 5 micron beam diameter, nominally 30 s on peak) is in the PDF attachment.
Cheers,
Andrew Locock
-
Hi,
I have a controversial suggestion - to see what you think. Currently TDI only applies to first row elements. This restricts it to the first element on each of the spectromters. I'd like to suggest that it could be used for second row elements - if it was done carefully checking that the intensity was a linear drop of with time - then it can be done for the second row elements. A case were it might be useful is volcanic glass with 2 TAP, 2 PET, and 2 LIF. Where Al is measured after Si (i.e. can't measure Si, Al and Na in first row). Currently you have to make sure its stable for the second row Al, so having to make sure Al is linear drop off is not much harder?
Ben
I saw this old post looking for something else and realized that I should have mentioned to Ben that one can apply TDI corrections to multiple sample setups (each with 5 elements per sample), then acquire them in the Automate! window and then combine them post acquisition using the Combine Samples into a New Sample feature from the Analyze! window:
https://probesoftware.com/smf/index.php?topic=40.msg12137#msg12137
That way one can utilize TDI corrections on more than 5 elements in a sample. Be sure to update to the latest Probe for EPMA using the Help menu as we fixed some minor bugs in this method earlier this year.
-
That way one can utilize TDI corrections on more than 5 elements in a sample.
But should you do that?
TDI is correcting for the change in intensity over time.
For the first set of elements, measured over time period 1, TDI is correcting for changes in the X-ray emission of the sample and ideally the regression provides data that correspond to "time zero" - the fresh, unirradiated original composition.
If TDI is applied to a second set of elements measured at the same spot, starting at time period 2, it will only be able to correct back to the composition of the sample as it was at the end of time period 1 = the start of time period 2.
The second application of TDI on the same analytical point is correcting back to an already-damaged/changed/altered material, not to the original composition.
It may be argued that some further correction is better than none at all, but it must be realized that a second set of TDI corrections during an analytical routine is not a panacea to obtain the actual original composition.
If the sample is sufficiently beam-sensitive that it continues to change during the measurement of a second set of elements,
perhaps a better analytical scheme should be used.
In the case of most zeolite minerals, for which the Fe content is effectively negligible, I find that simultaneous measurement of the 5 main measurable components: Na, Al, Si (all on TAP), K and Ca (both on PET) with a single application of TDI is sufficient.
Cheers, Andrew
-
Yes, of course, you are exactly correct. That is why we don't allow TDI corrections on subsequent elements in the first place! :)
But... and this is what Scott Boroughs does, he will digitize slightly different points for each of these sample setups, so they each get "virgin" interaction volumes. Of course that assumes that one's sample is homogeneous on the micro scale, but as you say, it's better than nothing.
In a way, this is similar to how the "assigned" TDI correction is acquired. The app "bumps" the stage a specified number of microns for each element and acquires TDI curves for each element separately, which can then be assigned to any subsequent (normally acquired) samples for a TDI correction.
-
One concern that has arisen multiple times by my users is how TDI is affected by the apparent/perceived lag between counting and when the Faraday cup is removed. In other words, does counting happen immediately after the cup is removed and there is simply a lag in the Acquire window display? Or is there really a lag between counting and the cup removal? If so, how does that affect the TDI calculation?
-
One concern that has arisen multiple times by my users is how TDI is affected by the apparent/perceived lag between counting and when the Faraday cup is removed. In other words, does counting happen immediately after the cup is removed and there is simply a lag in the Acquire window display? Or is there really a lag between counting and the cup removal? If so, how does that affect the TDI calculation?
There is always overhead on the microprobe communications. It's something we all have to deal with.
But the TDI acquisition zero time is referenced from the time the faraday cup is removed, not when the counting starts. So your users do not need to worry.
Note that you can try using different FaradayWaitOutTime values in the [Faraday] section of the Probewin.ini file. This is the amount of time that the program waits after the faraday cup is removed before counting starts. You might need to start a new MDB to test each different value.
-
interesting. As for peaksight, spectrometers firstly move to the positions, then beam current is measured, and then counting starts at once the faraday cup is disengaged (Had not noticed any human perceptible delay). I guess the sequence of steps as instruction in machine code are first copied to microprocessor memory and then executed there, at least I would do so. For TDI builtin hardware sequencer rather should be used and not direct commands to count, read, reset and repeat again and again. It should get counts as array binned by set timespan per bin. The same as with mapping, just without moving the stage. Actually I got an idea - in case the probe controll api for TDI do lots of PC<->probe communications, the mapping or (even better) line-crosssection API mode could be overused for this with set length of few nm or 0 (depends if firmware has no "divide by 0" gotchas) - pixels of line will contain equally spaced in timeline counts spaced equally by hardware with no relevant lag or glitch.
Another thought - counting is in hardware (there are 24bit counters implemented in FPGA) if they are reset prior launch (which should take place during initial spectrometer moving to the positions), only a single clock cycle is needed to start them, at 16 MHz the delay will be about 1-2µs which would translate into at most one or two pulse counts missed (in case of over-saturated count rate, but TDI then is the least concern). (FPGA in new gen on cameca electronics work at 50MHz thus delay is rather even more irrelevant). Unless software is micromanaging and sending every command sequentially (Hopefully rather not either with Peaksight and either with PfS).
Just for the record, there is also delay of beam hitting the sample after disengaging the faraday cup due to inductance of the beam and beam control deflectors. It is more visible where beam needs to be deflected to the faraday cup, instead of faraday cup being mechanically inserted into the beam. Thus there could be actually opposite delay - counting being engaged before beam drifts into the right spot.
-
interesting. As for peaksight, spectrometers firstly move to the positions, then beam current is measured, and then counting starts at once the faraday cup is disengaged (Had not noticed any human perceptible delay). I guess the sequence of steps as instruction in machine code are first copied to microprocessor memory and then executed there, at least I would do so. For TDI builtin hardware sequencer rather should be used and not direct commands to count, read, reset and repeat again and again. It should get counts as array binned by set timespan per bin. The same as with mapping, just without moving the stage.
I wish I could have coded it that way, but I had to write TDI code that works for both Cameca and JEOL instruments and JEOL does not have this capability, at least not for non-mapping acquisition modes.
And yes, PFE also performs all necessary instrument functions before removing the faraday cup. The delay after the faraday cup is removed isn't noticeably long on the Cameca. But JEOL instruments have another problem which is that the JEOL picoammeter is very slow. So when inserting the faraday cup, we often have to wait up to 2.5 seconds(!) before we can obtain a stable beam current measurement. This is not a problem at the start of the point measurement, but it can be problematic in the second beam current measurement.
In fact each model JEOL instrument seems to have a slower picoammeter. The 89800/8900 picomameter was actually quite fast, essentially as fast as the Cameca. Then the 8200/8500 was slower often requiring up to 1.5 seconds of delay after removing the faraday cup. And as mentioned above the 8230/8530 picoammeter is even slower.
This is not a problem for the TDI measurement because we're not measuring the absorbed current after removing the faraday cup (unless you are using the measure absorbed current option with TDI!), but if someone is measuring absorbed currents normally and has set the FaradayWaitOut too long (in order to obtain accurate absorbed current measurements), there will be an appreciable delay before the counting starts (if we were really smart we would measure absorbed current during the x-ray intensity measurements- need to think about that!).
Note that PFE measures the faraday current both before and after each x-ray measurement and can also measure the absorbed current measurement before and after the x-ray measurement (when the faraday cup is removed).
I think the best compromise for JEOL instruments might be to set FaradayWaitOutTime to zero in the Probewin.ini file (for timely TDI measurements), then set the Incubation/Decontamination delay time (in the Acquire! | Acquisition Options dialog) from zero to a couple of seconds when you aren't measuring TDI but need to obtain accurate absorbed current measurements.
https://probesoftware.com/smf/index.php?topic=116.0
Or JEOL could provide a faster picoammeter... maybe one of you electronics geniuses could come up with a fast picoammeter circuit for JEOL instruments? In other words, why did JEOL slow down their picoammeter so much over the last several decades?
-
...then set the Incubation/Decontamination delay time (in the Acquire! | Acquisition Options dialog) from zero to a couple of seconds when you aren't measuring TDI but need to obtain accurate absorbed current measurements.
This feature is shown here:
(https://probesoftware.com/smf/gallery/395_01_03_24_11_10_05.png)
By incubation time we mean the delay that may be necessary to account for the time is takes for the ion migration to begin after the faraday cup is removed (the interaction volume needs to heat up), though this can be resolved also by simply increasing the beam current.
The decontamination time is the same feature but used to delay the measurement of carbon (again, after the faraday cup is removed), in order to provide time for the beam to "burn off" any surface hydrocarbon contamination when measuring trace C Ka.
-
Apologies if this has been addressed in this thread already--
Have you considered adding a test for regression significance that if not met would turn off the TDI correction on a point-by-point and analyte-by-analyte basis? This was TDI would only be applied if it was statistically justified.
Below is copied from an example of how we do this with time-resolved LA-ICP-MS analyses. It seems like a similar approach would be helpful by EPMA if possible to implement.
https://jlubbersgeo.github.io/lasertram/explanation/
We determine the significance of each regression by evaluating following null hypothesis: there is no relationship between a given analyte's internal standard normalized ratio and time. We reject this if both the following conditions are true: The p-value for the coefficient (i.e., slope) is significant; The F-statisic comparing the regression and observed data is greater than the critical F value. By default, we set the threshold for p-value significance at .01 (i.e., we have 99\% confidence that we can reject the null hypothesis) in an effort to mitigate drift correcting all but the most linear of changes in normalized count rates, but this may be changed by the user. If the null hypothesis for a given analyte is rejected, the analyte is linearly corrected for drift and the regression parameters (e.g., slope and intercept) are used to calculate a normalized count rate for the calibration standard at the point in time where an unknown was analyzed: where is the regression slope, is the analysis time, and is the intercept for analyte .
-
Have you considered adding a test for regression significance that if not met would turn off the TDI correction on a point-by-point and analyte-by-analyte basis? This was TDI would only be applied if it was statistically justified.
Almost everything is possible, given enough time and resources! :D
Not a bad idea, we will consider the suggestion.