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Monochromator

Monochromator. Improvements and Focusing Elke Jackson Research performed by Elke Jackson, Shannon Lunt, and Yenny Martinez With the support of Drs. Steven Turley and David Allred. XUV Source. Monochromator Chamber. vacuum. vacuum. Octagonal Chamber. Monochromator Overview. XUV Source

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Monochromator

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  1. Monochromator Improvements and Focusing Elke Jackson Research performed by Elke Jackson, Shannon Lunt, and Yenny Martinez With the support of Drs. Steven Turley and David Allred

  2. XUVSource MonochromatorChamber vacuum vacuum Octagonal Chamber Monochromator Overview XUV Source • Hydrogen gas • High voltage • Plasma • XUV light • Slits • Vacuum

  3. Octagonal Chamber Zooming In:

  4. Multiplier Tube Octagonal Chamber Zooming In: • Pinhole selects beam • Stage/Detector: θ/2θ • Channeltron: Stage Pinhole θ 2θ Channeltron PhotonDetector

  5. Chamber Zooming In: First Order Diffractions Specular Reflection Entrance Beam Exit Beam Entrance Slits Exit Slits To XUV Source To Octagonal Chamber

  6. Reflective Diffraction Grating Grating Equation: mλ = d (sin α + sin β) Gmλ = (sin α + sin β) mλ = d cos K sin φ

  7. Reflective Diffraction Grating Grating Alignment • Mount new grating • Outside alignment with laser • Inside alignment with laser • Aligning the laser • Adjusting the grating • Alignment with source New grating: • 1200 lines per mm, twice that of the old grating • Half the width of the old grating

  8. Reflective Diffraction GratingAdjustments

  9. Focusing Centering beam • Small entrance beam focuses to small exit beam • Adjust monochromator settings to find beam through small slits Slit, adjustable width • Detector placement • Reduce slit width, keeping counts up • 10 micron goal • Centered beam

  10. Focusing:Detector scans at given slit widths • Curve shape does not change with slit size • Beam centered in slits

  11. Focusing:Wavelength scans at given lever arm micrometer settings • Adjusting the lever arm micrometer moves the grating • Maximize counts to the detector around wavelengths of greatest intensity by comparing wavelength scans at various micrometer settings Lever Arm Lever Arm Adjustment Micrometer

  12. Focusing:Wavelength scans at given lever arm micrometer settings

  13. Focusing:Wavelength scans at given lever arm micrometer settings

  14. Peaks of 16,000 counts (2 second intervals) Average standard deviation of 112 counts Now: Wavelength scans, lever arm at < 2.25 Similar optimization with cam micrometer Place pinhole and locate beam Bug fixes in computer program Stabilize source or determine its rise Write new standards of procedure to reflect changes Focusing:Wavelength scans at given lever arm micrometer settings

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