Excel spreadsheet for the FEL settings is here.

Is there an issue? Escalation Path

  • Issue concerns X-ray beam delivery: see here
  • Issue concerns ECS: see here
  • Prepare the hutch for the shift (done 1h before the actual start time)
    • open the grafana dashboards located here (requires UNIX login/pwd) to access beam owner, energies and coatings
    • no gate valve in the trajectory
      • check in the vacuum windows that no gate valves from the NEH to the MEC hutch are IN (red)
      • it is ok that the DG2 STP 1 is IN
      • it is ok that the GL window is IN in MEC

    • open the rolling status and confirm that no devices upstream the hutch obstructs the beam

      op.rs()

    • insert yag3 to provide a photon terminator before TCC prior to send any beam in the hutch

      op.yag3.insert()
    • confirm that the chamber is loaded with targets and being pumped down to be ready at the start of the shift
    • search the hutch but leave SH6 IN (you are not the beam owner yet)
  • 15 min before the shift begins, call ACR at x2151 to check
    • look at current ACR beam operator on shift here
    • confirm photon energy
    • confirm pulse energy
    • confirm pulse duration
    • confirm beam mode
    • confirm multiplexing mode
    • ask for an e-loss scan
  • transition to beam ownership
    • ACR calls you to confirm they are tweaking the beam for you
    • confirm with ACR that MR1L0 and MR2L0 have the right coating following this page
      • if moving the mirror yourself, then open MR1L0 and MR2L0 HOMS GUI located in the mechome > LCLS tab > HOMS overview button
      • set the coatings to the appropriate material as a function fo the photon energy as per the page from above
  •  getting ready to accept the beam:
    • close DG2 STP 1
    • make sure the reference laser is out (check in the rolling status)
    • confirm the target chamber is pumped down
    • insert the Be window IN the beamline
    • search H6 if not already searched
    • remove SH6 OUT of the beamline
  • beamline alignment
    • ACR calls you to confirm beam is ready for alignment

    • force close the pulse picker to make sure it does not let the beam propagate to the hutch yet

      op.pp.close()
    • check MR1L3 mirror OUT (-6000) position (XCS mirror)
    • check the XPP slits (slit1) are open (20mm, 20 mm) in the rolling status
    • open the mirror settings located here
    • confirm bending values for MR1L0 and MR2L0 (advanced)

    • insert YAG0

      op.yag0.insert()
    • confirm FEL beam is on the cross for the OUT position (undeflected beam)
    • confirm the shape of the beam is round (advanced)
    • set the MR1L4 coating as per this page
    • insert MR1L4
    • confirm FEL beam is on the cross for the IN position (deflected beam)

    • insert YAG1

      op.yag1.insert()

    • remove YAG0

      op.yag0.remove()

    • remove all Si attenuators (send full energy beam)

      op.SiT(1)

    • open the pulse picker

      op.pp.open()
    • fine tune the pitch of MR1L4 to center the beam on YAG1

    • insert YAG3

      op.yag3.insert()
    • remove hutch Be CRL (Mechome > Beamline > Beamline CRL(hutch))

    • open slit 2

      op.slit2.move(5)

    • remove YAG1

      op.yag1.remove()
    • fine tune the pitch of MR1L4 to center the beam on YAG3
    • to adjust the height using the YAG3 red cross centered at (265, 282), call ACR, and for a 200 mic motion on the yag, ask them to move 200/4 mic up or down.
      • you could set SiT(0.2) to not saturate the image
      • you could set 10 images averaged to get a cleaner picture
    • log the mirror settings in our table here
    • confirm photon energy and lens stack to use and log the change of stack in the paper document for Be CRL log
    • insert the Be lenses with these parameters
      • set 1: 9 keV, 9 x 300 mic, f = 3.96 m, Y = 2.8816 mm
      • set 2: 17 keV, 10 x 100 mic, f = 4.4243 m, Y = 29.52 mm
      • set 3: 22 keV, 9 x 50 mic, f = 3.904 m, Y = ?
  • once they are done tuning
    • timing check
      • turn off laser triggers

      • go to the titanium foil:

        op.ti()
      • move hutch CRL out

      • set slit4 to 400 mic: 

        op.slit4.move(0.4)

      • send full beam on titanium: 

        op.SiT(1)

      • set the EVR to 10 Hz settings: 

        op.lpl_check_timing(rate='10Hz')
      • set vertical division to 10 mV/div on oscilloscope Lecroy 1
      • once you see the signal of the X-rays, set 100 sweep to average the signal
      • save it on memory 2
      • set back sweeps to 1 on channel 2
      • move target about 0.8-1 mm negative to target the Al frame
      • turn on the LPL trigger on, event code 43 for 10Hz
      • once you see the signal of the LPL, set 100 sweep to average the signal

      • move timing to overlap the LPL with the memory trace 2 using the python command

        op.nstiming.mvr(2e-9)

        to move the LPL 2 ns later than the FEL, but this is just an example! Move it (or not) by the necessary amount to overlap best the rising edges of the beams.

      • save the current value as our t0, using hte python command 

        op.nstiming.save_t0()
      • once timed, set 100 sweep to average the signal and save the trace on memory 3
      • take a screenshot and put it in the elog
      • move back the hutch Be CRL
      • set the slits back to data-taking move size

      • set the EVR to single shot settings: 

        op.lpl_check_timing(rate='single')
      • set the scope Lecroy 1 channel 2 voltage/div to the maximum (1V/div) to be able to observe the shot on the diode and monitor the timing
    • laser

      • select the laser pulse shape

        meclas.LPL.psmenu()
L3

        to choose pulse shape : 8ns flat top, max 80J

      • start by optimizing the conversion efficiency

        meclas.LPL.SHG_opt() 

      • finish by optimizing the pulse shape

        meclas.LPL.psefc10Hz(numIterQ=150)
    • detector 
      • confirm LPL event code is either 182 or 43 (precaution)

      • in python, set event sequencer to 120 Hz:

        op.x.start_seq(120)
      • aadd the detectors you want a pedestal for, remove any VISAR or slow cameras and allocate the DAQ

      • in a random DAQ terminal, execute

        takepeds

        and follow instructions

      • after takepeds is done, execute 

        makepeds -r xxx -u yourusername -q milano

        with xxx being the run number and yourusername being the user name of the person who extract the pedestal, then follow instructions

      • shutdown the DAQ (don't need to 'restartdaq'), reallocate and confirm the pedestal has been applied
      • alight Ge spectrometer 
      • check 4 Quads with calibrant sample (CeO2) for q range

1 Comment

  1. Eric M Galtier

    Timing with the diode shows that the X-rays were earlier by more than 500 ps. Looking at the VISAR change of reflectivity from the FEL, we found out that the X-rays were about 1.2 ns later in teh window. I changed the timing by 1.2 ns to match the previosu timing from yesterday before moving on. We know that the diode is not precise, maybe better than 500 ps, but hte fact tha tthe X-rays moved is weird. We need to keep an eye on it. Anyway, we should use heavily the 400 mic Lif coated in the front by 200 nm of Al for timing.