1. Turn off both the X-ray and laser beams before moving any motors
  2. Coarse align the gas cell x & y using SCC YAG and unfocused X-ray beam
    1. Check beam centered on DG1 slits, if not, make it center with MR2L0_HOMS_PITCH for horizontal, and call ACR for vertical alignment
    2. Move the pinhole out, leave only the gas cell
      1. We need to move the JungFrau detector (20mm) and gas cell (6mm) downstream in order to move the pinhole out
        1. Move the JungFrau first - 20mm downstream
        2. Then the gas cell - 6mm downstream
        3. Last the pinhole - to -50 (out position)
    3. SC3 Clear YAG position:
      1. PI3 Y = 46.4559 (move this first)
      2. Ap Stand = -9
    4. Close DG1 slits to 0.15mm, set the marker around the corners on SC3 YAG:
    5. DG1 slits open to 0.3mm, optimize gas cell x and y by looking at the marker position related to the circle:
    6. Then the gas cell x & y should be aligned to the DG1 slits.
  3. Coarse align the gas cell pitch & jaw using SCC YAG and unfocused X-ray beam
    1. With the unfocused beam (we shouldn’t change gas cell pitch & yaw with focused beam at JungFrau), looking at the beam on SSC clear YAG
      1. cxi _sc3_inline camera
      2. ~0.01 - 0.05 transmission (use as low as you can see the beam clearly)
    2. Find the motor position for the “moon” shape 
    3. Center each “moon” with one motor position when the other motor position is intentionally off-centered for creating the “moon”
      1. Angle step: 0.1 or 0.05°
      2. Do this to both directions, write down the good position before intentionally off centering it
      3. Move both directions to the good positions
      4. Moon examples: and
    4. Then the gas cell pitch & jaw should be aligned to DG1 slits.
  4. Coarse align the pinhole x & y:
    1. The image without the pinhole looks like this:
    2. The image with aligned pinhole looks like this:

    3. Then the pinhole x & y should be aligned to DG1 slits. If it’s not aligned, it will cut into the beam image. 

  5. Fine align the pinhole x and y with focused x-ray beam, by looking at the JungFrau HitFinder 2D plot
    1. NOTE: every slit and lens is aligned to the DG1 slits!!! If later we find the beam is not centered, we should move the beam pointing by HOMS and ACR undulator pointing.
    2. Move prefocus lens in, check if it’s centered to DG1 slits on DG1 YAG:
    3. Move DG2 focus lens in, check if it’s centered to DG1 slits on DG2 YAG:
    4. The goal is to make the no-sample scattering (vacuum background with X-ray)
      1. As small as possible
      2. As uniform as possible
    5. Movement step should be small
      1. Translation step: 0.005mm or 5um
    6. Set JungFrau4M_chA HitFinder threshold to 300 and create the HitFinder area plot, use the plot as our reference for fine aligning the cell; we can also use
      1. Starting with low pulse energy (~1E-4 transmission)
      2. Once it’s aligned so that almost nothing can be seen, we can ramp up the transmission to 1E-3, then 1E-2
      3. Fine tune pinhole x & y by looking at the scattering, try to make it as small as possible, and as uniform as possible
      4. Eventually, we will run with the full power
    7. Collect background data, let the data team to analyze and tell us how it compares with old background or with different motor positions