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Is there an issue? Escalation Path

  • Issue concerns X-ray beam delivery: see here
  • Issue concerns ECS: see here

Initial Spatial overlap between LPL, VISAR and X-rays

  • This procedure assumes that
    • the beamline is aligned up to yag3
    • the slits are aligned to the beam
    • the yag at TCC has been prealigned with the help of Questar 2 as well (for maximum accuracy) and the pin (the pin is used to measure the LPL spot size and set the plan of interaction)
  • Go to the yag at TCC

    op.yag()
  • Remove the hutch Be CRL
  • Close slits 4 to 50 mic

    op.slit4.move(0.05)
  • Set a cross on Questar 1 screen and write down the X and Y positions in the preset spreadsheet of the experiment
  • Close the pulse picker and reinsert the Be CRL

    op.pp.close()
  • Move to the pinhole

    op.pinhole()
  • Tweak the position of the pinhole until it is centered on the cross

    x.hex_y.tweak(0.02)
    x.tgx.tweak(0.02)
  • Save the new pinhole position

    op.pinhole_s()
  • Move back to the yag

    op.yag()
  • Send the VISAR laser with event code 43 and enable the trigger
  • Confirm that the focus of the VISAR provides a sharp and round image on any VISAR cameras (Visar gige 1 and 2)
  • Tweak the focus of the visar position accordingly (50 mic steps is good enough)

    op.visar_z.tweak(0.05)
  • Turn off the VISAR trigger
  • Prepare the system to check the front alignment of the drive lasers

    op.check_front_alignment()
  • Check spatial overlap of the drive beams ABEF and GHIJ successively by centering the scattered signal on the cross of Questar 1 screen

    op.TTL_shutter.Toggle("openABEF")
    op.TTL_shutter.Toggle("closeGHIJ")
    x.lpl_west_x.tweak(0.05)
    x.lpl_west_y.tweak(0.05)
    op.TTL_shutter.Toggle("closeABEF")
    op.TTL_shutter.Toggle("openGHIJ")
    x.lpl_east_x.tweak(0.05)
    x.lpl_east_y.tweak(0.05)
  • Record each positions of the VISAR and drive lenses in the experiment spreadsheet

Initial Temporal overlap between LPL and X-rays

  • go to Ti sample

    op.ti()
  • remove the Be CRL
  • open slit4 to 400 mic

    op.slit4.move(0.4)
  • set full X-ray transmission

    op.SiT(1)
  • open the pulse picker

    op.pp.open()
  • Open the TCC scope

    op.scope_timing_remote()
  • Set the EVR of the scope to 10Hz

    op.lpl_check_timing("10Hz")
  • Set channel 2 to 2 or 5 mV/div
  • Confirm that the X-ray pulse is seen around 60 ns.
  • Average over 100 sweep and save the trace on M2 (from C2)
  • Set the sweep averaging back to 1
  • Close the pulse picker

    op.pp.close()
  • Insert the filter in front of Questar 1

    op.fw(num=1, position=3)
  • Set the laser pulse shape to the timing shape

    op.LPL.psmenu()
    LXX
    op.LPL.psefc10Hz()
  • Send the 10Hz LPL (enable the trigger of the ns slicer) on target at full energy

    op.HWPon('all', set_T=1.0)
  • Set the channel 2 to 10 mV/div
  • Confirm you see a trace on C2
  • Average over 100 sweep and save the trace on M3 (from C2)
  • Set the sweep averaging back to 1
  • Take a screenshot and post it to the elog
  • Set the channel 2 to 1V/div
  • Set the scope to single shot trigger

    op.lpl_check_timing("single")
  • Further fine timing can be done by using a LiF coated window
    • Move to the appropriate target
    • Confirm Be CRL are inserted in the beamline
    • Set the timing of the drive to 0

      op.nstiming.mv(0e-9)
    • Confirm that the streak window have zero offset in the window size requested

    • Take a single refence only shot to observe the change in reflectivity at the arrival time of the X-rays

      op.ref_only(
      	xray_trans=1,
      	xray_num=1,
      	shutters=False,
      	dark=0,
      	daq_end=True,
      	calibrant="",
      	rate=1,
      	visar=True,
      	save=True,
      	slow_cam=False
      )
    • To double check, confirm timing at another step

      op.nstiming.mv(10e-9)
      op.ref_only(
      	xray_trans=1,
      	xray_num=1,
      	shutters=False,
      	dark=0,
      	daq_end=True,
      	calibrant="",
      	rate=1,
      	visar=True,
      	save=True,
      	slow_cam=False
      )
    • Fine tune the timing is the X-ray trace is not where it is expected using the nstiming.mv function accordingly.

Check Spatial overlap between LPL, VISAR and X-rays on target

  • Start by moving to the desired target (refer to the python manual here for details on the arguments)

    op.move_to_target(config="colinear", frame_cfg=[1, "F1", 1, "F2", 1, "F3"], frame=2, target="A2")
  • Continue by checking the alignment of the drive lasers

    • Set the system in a mode where the laser energy is minimum, the filter is removed from questar 1 and the trigger is enabled

      op.check_front_alignment()
    • Confirm you see a scattering signal close to the X-ray cross (342, 561)
    • Move the hexapod X axis to center the beams on the cross and produce a round scattering signal (steps of 50 mic is good)

      x.hex_x.tweak(0.05)
  • Continue by checking the alignment of the VISAR system
    • Adjust the VISAR Z axis to make sure the image is round and sharp (could be set to the value by using the right equation as well). Steps of 50 mic is good.

      x.visar_z.tweak(0.05)
    • Alternatively, move the Z value by exactly the thickness of the ablator + material of interest and add the change in position due to the visar window. To calculate the change use the following command

      op.visar_window_compensation(material="LiF", thickness=400e-6)

Take reference images with VISAR and/or X-rays

  • For 5 references with VISAR and X-rays (at 20% max)

    op.ref_only(
    	xray_trans=0.2,
    	xray_num=5,
    	shutters=False,
    	dark=0,
    	daq_end=True,
    	calibrant="",
    	rate=1,
    	visar=True,
    	save=True,
    	slow_cam=False
    )

Take a driven shot with the LPL

  • For a driven shot at full energy (lpl_ener=1.0), with X-rays arriving 5 ns later (timing=5.0e-9) at full intensity (xray_trans=1) use the following command

    op.optical_shot(
    	shutter_close=[1, 2, 3, 4, 5, 6],
    	lpl_ener=1.0,
    	timing=5.0e-9
    	xray_trans=1,
    	xray_threshold=0.2,
    	save=True,
    	daq_end=True,
    	auto_trig=True,
    	auto_charge=True,
    	visar=True,
    	debug=False,
    	ps_opt=True
    )


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