Page History

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•  align the beamline with no CRL from source to Zyla
•  set and log all references in the preset file here
•  Timing
  •  At TCC
    •  Coarse timing
      •  X-rays
        •  insert prefocusing lenses only and go to the 45° Ti foil
        •  send full X-rays and confirm a trace of the X-rays on the scope channel 2 while triggering off channel 1
        •  record positions with a better than 20 ps accuracy on M2
      •  SPL
        •  close the iris to obtain a say 50 mic spot on target
        •  with the GAIA timed out, but with full amplified SPL, remove the energy limiter
        •  send the beam on the same 45° Ti foil
        •  observe the optical trace from the SPL: if it cannot be seen, either trigger from the channel 2 and find how much we are off, or open a bit the iris
        •  move the SPL timing to bring the SPL trace coincident with M2 on the rising edge
        •  record positions for the VITARA and scope
    •  Fine timing
      •  close the iris to fully illuminate the imaging system for the spot size while the GAIA is timed out and the EL is OUT
      •  move to the 45° Yag crystal extending from the pillar
      •  send the optical laser then send the X-rays at full beam
      •  timing should be within 20 ps, so changing the VITARA timing by 1 ns should allow us to see the image turn black. Closing the slits to 400 mic for the X-rays help see the localized change of indesx of reflaction
      •  once you see a darkening, follow the procedure below to get timed
        •  go back half the last step you just did (let's assume you are going negative on the vitara)
        •  if you see no darkening, it means you passed t0 and you can go back positive again half the step size you did just before
        •  if you see drkening, you didn't go far enough, so keep going negative until the darkening disappear
      •  once the timing is done within 100 fs, close the slits to 50 mic and confirm spatial overlap with the pin at TCC
      •  record positions of the VITARA for t0 and positions of the varioous targets to be able to go back quickly to this configuration and check timing
    •  with the TSO imaging and the 45° YAG extending from the pillar,
  •  At the time tool
    •  Coarse timing
      •  once timing has been done at TCC, timing at the time tool can start
      •  insert the Ti foil of the time tool in the beam
      •  send full X-rays on the foil and look at scope channel 2
      •  if you see a signal, save it on M3, if not, trigger on this channel and see how far you are from the trigger on channel 1
      •  observe the position of the timetool signal vs the X-ray signal taken on M2 at TCC: the difference will help you iterating for timing below
    •  Fine timing
      
      •  insert the yag crystal and send the SPL time tool beam onto the camera
      •  align the cracks in the crystal to be in focus
      •  send the X-rays full beam and look at any darkening of the image
      •  if you see no darkening, it means you are still too early with the timetool
        
        •  to change the timing of the time tool, you can first estimate how far you are by keeping the delay stages of the timetool where it is and move the VITARA only. The value you started from is the one needed to be timed at TCC, so this value will need to be set back once timing at the time tool has been done.
        •  change the VITARA until you see a darkening, using the bracketing of the value found out above (when comparing M2 and M3)
        •  once you have found darkening, do the usual bracketing techniques to narrow down the window to 100 fs and see the edge moving in the frame of the timetool
        •  go a bit later with the SPL and close the slits to 50 mic with the FEL to center the time window in the image: t0 is shown at this cross
        •  record the VITARA value and compare to the original value found for t0 at TCC: this difference is the amount which needs to be either added or subtracted in the delay arms of the time tool
      •  get in the hutch and add/subtract the relevant beampath in the time tool: realign the beam path if need be
      •  confirm VITARA is set at TCC t0 and send the SPL and X-rays
      •  if you are close in timing (can be checked with the VITARA), use the delay line of the timetool to get to t0 at the cross set before on the timetool camera
      •  record the delay line values and positions on the screen for timing
      •  check signal strength with the other samples (e.g. thick SiN membranes)
    •  Temporal calibration
      •  open the slits to 2 mm in the temporal direction and 400 mic in the spatial direction
      •  confirm you see the edge moving in the vue
      •  move the VITARA to the bottom of the screen and record 1000 events at this position: note the VITARA value and the expected change in timing
      •  save a reference of the timetool picture with no xrays for background sutraction: 1000 events is likely necessary
      •  repeat the step above with 3-4 steps until you reached the top of the screen
      •  plot the histogram of the edge position for each run on the same graph (X is pixel, Y is hist)
      •  extract the centroid of the distribution at each time steps: this is the actual center of the jitter to be used for the calibration at the time set in the VITARA
      •  extract the width of each histogram: this is the actual jitter of the X-rays vs the SPL and confirm it is the same at each time steps
      •  plot the centroid (pixel) vs time (VITARA value) and interpolate with a linear function: the slope gives us the fs/px correspondance (this is the time calibration)
      •  set the delay on the VITARA to a known amount and confirm by counting the pixel from the centroid to the cross on the screen and applying the fs/px value that it corresponds
        
      •  if not, repeat the calibration process starting from the top of the screen and finishing at the bottom (problem might be caused by the VITARA backlash)
•  MXI alignment at 11 keV
  •  confirm the alignment of the pins at about 0 mm position on X of the MXI hexapod
  •  start alignment with x2 on the Zyla objective
  •  

    set full energy beam without prefocusing lenses in to start with

    Code Block
    language py theme RDark linenumbers true
    op.SiT(1)

  •  move +14mm relative to this position to get to the 50 x 50 mic stack for 11 keV
  •  if you are lucky, you might see light through the MXI
    •  if yes, start aligning the lenses with the 'fish eye' method: intentionally move V to create a symmetric pattern on the image and align tip, then intentionally move U to create a symmetric pattern on the image and align tilt
    •  once both axis are symmetric, close the slits to 50 mic and translate X and Y to center the image on the original beam position when the MXI was out
    •  keep iterating until the feature is round
  •  record positions of the hexapods at this Z value in the preset to be able to come back when necessary
  •  save this position on the first preset of the virtual motor
  •  align the virtual motor by moving Z 10 cm away and realigning the MXI following the steps above
  •  once done, save the position on the second preset of the virtual motor
  •  confirm alignment by moving 10 cm away in Z using the virtual motor only
  •  save 1000 images of the beam going through the MXI and no target at TCC
    •  confirm the XRT spectrometer is in
  •  insert a Siemens star at TCC
  •  reduce intensity to 1%

    Code Block
    language py theme RDark linenumbers true
    op.SiT(0.1)

    or 10% if you see nothing

  •  confirm you image the siemens star pattern correctly
    •  play with the focus of the MXI until the image is the sharpest
    •  update the virtual motor
    •  save runs of 1000 images (could be 10 x 100)
  •  you might try to image other samples
    •  try the targets produced at Stanford and experience alignment procedure

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