Beamline Alignment Quick Reference: Difference between revisions
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NOTES:<br /> | NOTES:<br /> | ||
i) If DCM theta looks low (~2-4 deg) you may need to re-set user offset (current calibrated theta offset = dial + 8.646deg) <br /> | i) If DCM theta looks low for the current energy (~2-4 deg) you may need to re-set user offset (current calibrated theta offset = dial + 8.646deg) <br /> | ||
ii) Approximate Si 111 Bragg Theta = asin(1.977084/E keV)<br /> | ii) Approximate Si 111 Bragg Theta = asin(1.977084/E keV)<br /> | ||
iii) Approximate undulator offsets are ~ desired energy +0.1 keV <br /> | iii) Approximate undulator offsets are ~ desired energy +0.1 keV <br /> | ||
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i) mirror piezo feedback should be OFF <br /> | i) mirror piezo feedback should be OFF <br /> | ||
ii) CCD shutter should be set to "manual open"<br /> | ii) CCD shutter should be set to "manual open"<br /> | ||
<br /> | |||
''' | '''3) Scan DCM roll:'''<br /> | ||
Set slits to | Set slits to | ||
{| {{table}} style="text-align:center" | {| {{table}} style="text-align:center" | ||
| Line 42: | Line 43: | ||
| NES || 0.2 || 2 | | NES || 0.2 || 2 | ||
|- | |- | ||
| BDA || | | BDA || 2 ||| - | ||
|} | |} | ||
scan roll +/- 0.15 mrad. Set roll to maximum<br /> | |||
NOTES:<br /> | |||
i) Correct for backlash by driving to first scan point, then to maximum (e.g. after scan drive relative -0.15, then drive abs to max)<br /> | |||
ii) Settling time of at least 1 second (this axis is UHV picomotor driven in PID) | |||
Revision as of 18:54, September 7, 2010
Back to X-Ray Microscopy
1) Select x-ray energy:
Calculate scattering angle of Si 111 for desired energy with Bragg law calculator
Drive DCM Theta to the correct Bragg angle for the desired energy, drive undulators approximately to this energy as well
NOTES:
i) If DCM theta looks low for the current energy (~2-4 deg) you may need to re-set user offset (current calibrated theta offset = dial + 8.646deg)
ii) Approximate Si 111 Bragg Theta = asin(1.977084/E keV)
iii) Approximate undulator offsets are ~ desired energy +0.1 keV
2) Scan mirror piezo:
Set slits to
| Slit | H Size (mm) | V Size (mm) |
| PBS | 0.2 | 2 |
| NES | 2 | 2 |
| BDA | 2 | - |
scan mirror piezo +/- 1 V. Set mirror piezo to the maximum.
NOTES:
i) mirror piezo feedback should be OFF
ii) CCD shutter should be set to "manual open"
3) Scan DCM roll:
Set slits to
| Slit | H Size (um) | V Size (um) |
| PBS | 0.2 | 2 |
| NES | 0.2 | 2 |
| BDA | 2 | - |
scan roll +/- 0.15 mrad. Set roll to maximum
NOTES:
i) Correct for backlash by driving to first scan point, then to maximum (e.g. after scan drive relative -0.15, then drive abs to max)
ii) Settling time of at least 1 second (this axis is UHV picomotor driven in PID)
3) Scan DCM pitch:
Set slits to
| Slit | H Size (um) | V Size (um) |
| PBS | 2 | 2 |
| NES | 2 | 2 |
| BDA | 0.025 | - |
and scan pitch +/- 0.05 mrad. Set pitch to max.
4) Scan DCM Bragg: