2023.09.29_ Shift 3 _haelee

Excel spreadsheet for the FEL settings is 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 : 17 keV
  • confirm pulse energy : ~ 0.5 mJ → ~0.3 mJ in reality
  • 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
  • check 'MR1L3' mirror OUT (-6000) position (after XCS)
  • insert YAG0 ([1] op.yag0.insert())
  • confirm FEL beam is on scale "0"
  • confirm the shape of the beam is round
  • insert YAG1 ([1] op.yag1.insert())
  • insert MR1L4 : check coating for photon energy
  • confirm on yag0 that the beam is properly deflected on the scale "8 cm"
  • remove YAG0
  • remove all Si attenuators ([1] op.SiT(1))
  • open the pulse picker ([1] op.pulse_picker("open"))
  • fine tune the pitch of MR1L4 to center the beam on YAG1
  • insert YAG3 ([1] op.yag3.insert())
  • remove YAG1
  • fine tune the pitch of MR1L4 to center the beam on YAG3
  • log the mirror settings in our table here
    
• once they are done tunning
  
  • 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)

    • look at scope 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 scope channel 2 voltage/div to the maximum (1V/div) to be able to observe the shot on the diode and monitor the timing
    • set the event code for the TCC diode to 182 so it triggers on LPL shot (open the EVR SLAC USR 01, and look for the second line of EVR which says 'TCC diode trigger')
  • 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