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- Move MONO to the energy corresponding to the end of your desired XAS scan energy range.
- This number can be found by going to the Regions window and selecting the scan region you will use. Look towards the bottom of the window for the "stop energy" value.
- Alternatively, if the scan region is not yet defined, set energy to (edge energy + 1000 eV) if you plan to run EXAFS, or (edge energy +200 eV) if you plan to run only XANES.
- In XASUTILS window, select the “Mono Tuning” tab. Move the tuning in one direction or the other while monitoring I0 signal, until you reach a maximum in I0.
- If one click of the "Mono Tuning" seems too large or doesn't seem to move the I0 value at all, you can decrease or increase the Mono Tuning step size.
- If detuning is needed (see below), you will want to "Detune" with the UP arrow in the "Mono Tuning" interface.
- BL 4-3 runs with a harmonic rejection mirror, with energy cutoff at either 4 keV, 6 keV, or 10 keV, depending on what the beam line engineer has set it to.
- Because the mirror is bare Si and not coated with a metal, the cutoff is more gradual than other beam lines.
- If your harmonic energy (equal to 3x the MONO energy) is less than 4 keV above the cutoff energy, at least 25% detuning is recommended. Otherwise you can run fully tuned (maximize I0 to 100%).
- You may also want to detune some if you are looking at a dilute sample at lower energy edge (E < 4 keV) and sample matrix has a lot of a heavier element in it (e.g. Fe, Ti, Cr, etc.)
- Example 1: S edge (~2.5 keV), 4 keV cutoff. Harmonic energy is 7.5 keV, which is only 3.5 keV above the 4 keV cutoff. Detune 25% (reduce I0 to 75% of maximum)
- Example 2: S edge (~2.5 keV), 6 keV cutoff. Harmonic energy is 7.5 keV, which is only 1.5 keV above the 6 keV cutoff. Detune 35% (reduce I0 to 65% of maximum)
- Example 2: S edge (~2.5 keV), 10 keV cutoff. Harmonic energy is 7.5 keV, which is below the 10 keV cutoff. Detune 50% (reduce I0 to 50% of maximum)
- Example 4: Ti edge (~4.9 keV), 6 keV cutoff. Harmonic energy is 14.7 keV, which is 9 keV above the 6 keV cutoff. Run fully tuned (maximize I0 to 100%)
- Example 4: Ti edge (~4.9 keV), 10 keV cutoff. Harmonic energy is 14.7 keV, which is 4.7 keV above the 10 keV cutoff. Run fully tuned (maximize I0 to 100%)
- Example 5: Fe edge (~7.1 keV), 10 keV cutoff. Harmonic energy is 21.3 keV, which is 11 keV above the 10 keV cutoff. Run fully tuned (maximize I0 to 100%)
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- Move MONO to the energy corresponding to the middle of your desired XAS scan energy range.
- This number The ending energy of your XAS scan energy range can be found by going to the Regions window and selecting the scan region you will use. Look towards the bottom of the window for the "stop energy" value.
- Set MONO to the midpoint between your edge energy and the "stop energy" value
- Alternatively, if the scan region is not yet defined, set energy to (edge energy + 500 eV) if you plan to run EXAFS, or (edge energy + 100 eV) if you plan to run only XANES.
- Close S1VGAP to 1.0 mm and S1HGAP to 10.0 mm.
- Scan TABLEVERT motor while looking at I0 signal.
- TABLEVERT scan parameters and apperance depend on mirror cutoff selected
- If at 4 keV cutoff:
- Scan +/- 3.5 mm, with 0.35 mm point spacing (Or use "rel3_5" align region from drop down).
- Select peak slightly to left of center of plateau. Hit "Accept position" Do NOT select peaks at either right or left side of plateau.
- If at 6 keV cutoff:
- Scan +/- 2.5 mm, with 0.25 mm point spacing (Or use "rel2_5" align region from drop down).
- Select peak on right side of scan. Hit "Accept position".
- If at 10 keV cutoff:
- Scan +/- 2.0 mm, with 0.2 mm point spacing (Or use "rel2" align region from drop down).
- Select peak value of I0. Hit "Accept position".
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