MAN versus Off-peak Background Measurements What Is It Good For? Saving TIME!
How Much Time? 186 seconds w/ Off-Peaks 94 seconds w/ MAN
What Else is it Good For? Avoiding Off-Peak Interferences Spectrometer Reproducibility Issues Sensitive Samples Quantitative Imaging Avoiding Wear and Tear on Spectrometers
Avoiding Off-Peak Interferences By not measuring off-peak intensities in samples of unknown composition, one can eliminate even unforseen off-peak interferences.
Spectrometer Reproducibility Issues Ultra High Precision Measurements Handle spectrometer re-positioning problems By reserving a spectrometer for a single MAN corrected element x-ray line (monochromator), one can obtain:
Na/K Loss in glass (or Si/Al “grow-in”) Sensitive Samples Na/K Loss in glass (or Si/Al “grow-in”) Everyone knows about sodium loss over time in some glasses and especially, hydrous phases- but did you know that sodium can also “grow-in”?
Sodium Calcium Silicate (cement “gel”)
(512 x 2048 pixels @ .5 sec equals 6 days!) Quantitative Imaging Eliminate acquisition time for off-peak intensity images and still obtain background corrected quantitative images (512 x 2048 pixels @ .5 sec equals 6 days!)
How Good Is It? Major Elements Minor Elements Trace Elements Comparison to Off-Peak Measurements Matrix Issues (Low Z-bar vs High Z-bar) Accuracy (reproducibility, drift, etc)
Comparison with Off-peak 20 kev, 20 nA, 5 um, 20 sec on, 20 sec off St 305 Set 2 Labradorite (Lake Co.) ELEM: Ca K Fe Ti Na Al Mn Ni O H Si SUM AVER: 9.625 .102 .326 .023 2.841 16.529 .008 .003 46.823 .000 23.957 100.239 SDEV: .036 .008 .018 .014 .039 .032 .008 .005 .000 .000 .000 %RSD: .4 7.7 5.5 61.8 1.4 .2 89.4 165.7 .0 .0 .0 PUBL: 9.577 .100 .319 n.a. 2.841 16.359 .000 n.a. 46.823 n.a. 23.957 99.976 %VAR: .51 1.69 2.29 .00 .01 1.04 .00 .00 .00 .00 .00 DIFF: .048 .002 .007 .000 .000 .170 .000 .000 .000 .000 .000 STDS: 358 374 395 22 305 374 25 28 0 0 0 PKBG: 137.20 3.16 4.33 1.35 34.33 217.83 1.09 1.00 .00 .00 .00 MAN St 305 Set 2 Labradorite (Lake Co.) ELEM: Ca K Fe Ti Na Al Mn Ni O H Si SUM AVER: 9.640 .100 .321 .023 2.864 16.543 .002 .004 46.823 .000 23.957 100.277 SDEV: .034 .007 .017 .012 .037 .033 .003 .005 .000 .000 .000 %RSD: .3 7.1 5.4 51.9 1.3 .2 140.3 126.3 .0 .0 .0 PUBL: 9.577 .100 .319 n.a. 2.841 16.359 .000 n.a. 46.823 n.a. 23.957 99.976 %VAR: .65 .23 .78 .00 .81 1.13 .00 .00 .00 .00 .00 DIFF: .063 .000 .002 .000 .023 .184 .000 .000 .000 .000 .000 STDS: 358 374 395 22 305 374 25 28 0 0 0 PKBG: 171.37 3.06 4.10 1.33 47.17 258.11 1.00 .99 .00 .00 .00
High Z-bar Off Peak Comparison 20 kev, 20 nA, 5 um, 20 sec on, 20 sec off St 396 Set 2 Chromite (UC # 523-9) ELEM: Ca K Fe Ti Na Al Mn Ni O H Cr SUM AVER: .002 .004 20.392 .333 .006 8.004 .162 .087 33.042 .000 31.905 100.349 SDEV: .003 .005 .109 .021 .009 .036 .013 .014 .000 .000 .000 .000 %RSD: 114.0 129.1 .5 6.5 156.9 .5 8.0 15.9 .0 .0 .0 .0 PUBL: n.a. n.a. 20.692 .300 n.a. 7.690 .225 n.a. 33.042 n.a. 31.905 100.266 %VAR: .00 .00 -1.45 10.84 .00 4.09 -28.03 .00 .00 .00 .00 .00 DIFF: .000 .000 -.300 .033 .000 .314 -.063 .000 .000 .000 .000 .000 STDS: 358 374 395 22 305 374 25 28 0 0 0 0 PKBG: 1.00 1.04 101.90 4.90 1.01 73.21 2.07 1.44 .00 .00 .00 .00 MAN St 396 Set 2 Chromite (UC # 523-9) ELEM: Ca K Fe Ti Na Al Mn Ni O H Cr SUM AVER: .001 .001 20.441 .346 .007 7.976 .155 .087 33.042 .000 31.905 100.372 SDEV: .002 .002 .109 .016 .009 .036 .014 .008 .000 .000 .000 .000 %RSD: 316.2 223.9 .5 4.5 118.4 .5 9.1 9.0 .0 .0 .0 .0 PUBL: n.a. n.a. 20.692 .300 n.a. 7.690 .225 n.a. 33.042 n.a. 31.905 100.266 %VAR: .00 .00 -1.21 15.40 .00 3.72 -31.27 .00 .00 .00 .00 .00 DIFF: .000 .000 -.251 .046 .000 .286 -.070 .000 .000 .000 .000 .000 STDS: 358 374 395 22 305 374 25 28 0 0 0 0 PKBG: .98 .98 133.63 5.76 1.04 57.37 1.97 1.44 .00 .00 .00 .00
Drift Issues in MAN Drift array background intensities for standards: ELMXRY: ca ka k ka fe ka ti ka na ka al ka mn ka ni ka MOTCRS: 2 PET 2 PET 4 LIF 3 LIF 1 TAP 1 TAP 3 LIF 4 LIF STDASS: 358 374 395 22 305 374 25 28 19.3 15.7 33.0 20.3 9.3 28.5 25.1 46.8 20.0 15.6 33.0 21.2 9.9 28.9 25.8 47.5 Drift array standard intensities (background corrected): 4564.9 2741.4 6926.4 2341.0 325.7 3296.5 6976.5 8176.6 4583.7 2745.9 6884.5 2305.0 327.5 3272.7 6960.2 8192.3
Typical Sequence of MAN Fit
Cr K-b interference removed
Trace Ni “contamination” removed (natural chromite, 0.087 wt. % Ni)