This procedure describes how to document and turn on the laser after long down times (i.e. Winter Closure) and power outages. This is not the daily procedure for turning on the pre-amp and MPA. That procedure is here. Note that this procedure is not sufficient for turning on the laser. You must have explicit approval to turn on the laser from the SLSO.


Starting the Laser

  1. Turn on the Revolution (Legend)
    1. Switch on the control box
    2. Confirm the LBO temperature set point on the control computer matches the value written on the control computer.
      1. If the setpoint is 75deg then go to Factory and turn off SHUTDOWN: Set LBO to 75 DEG
    3. Wait at least one hour until temperature stabilizes at the set point.
    4. Turn the key on the control unit to "on" (this allows the laser to be turned on using the control computer, it does not turn on the laser)
    5. Confirm the settings on the control computer "system" panel match the settings recorded at shutdown (you'll need to access the facet elog)
      1. Confirm: Q-Switch Mode, Q-Switch Pulse Width, Current Setting
      2. If you need to change Q-switch Mode it will pop up a warning about making sure you don't try to run the laser out of specifications. Acknowledge this warning.
    6. Turn on the pump lasers using the computer control panel (green RUN button). You will need to hold down the button until the control unit begins to beep.
  2. Turn on the Vitara
    1. Turn the key on the control unit to "on".
      1. If the software has I2C errors or the com error lights are on, try restarting the computer.
    2. Load presets ?? (these are the setting for 800 nm central wavelength)
    3. Turn on the pump laser using the computer control panel. Turn on "Remote", then turn on "Diode".
      1. Confirm control panel diode pump level is +/- 0.1W compared to shutdown value in ELOG
    4. Give laser time to modelock at 800 nm, confirm modelocking via computer control panel and using spectrometer (spectrum will be > 20 nm FWHM)
      1. If the spectrometer software is throwing errors, restart the computer
      2. If laser does not modelock, call the SLSO
    5. Enable the RF lock
      1. Power on the piezo amp (make sure the RF lock is DISABLED and stays disabled)
      2. Enable the RF lock
  3. Run through the shutdown images in the logbook and check shutdown values to current settings.
    1. "Document the Laser State" has a list of things to check: S20 Laser long-term shutdown procedure
    2. Pay close attention to the SDG. A power dip has somehow reset a heap of settings on the SDG.
    3. Check and adjust (if necessary) the motor positions for the laser room motion controller: MOC-LA20-LS24
    4. Check the SLAC timing system, confirm triggers match settings at shutdown. Sometimes settings aren't saved, so they are not restored after reboot. The most recent settings are on the diagram on the wall by the control computer.
  4. Measure the laser energy and post an entry to the logbook of the energy after the regen, after the pulse slicer, after the pre-amp, after the MPA.


Possible Issues

  1. Vitara doesn't mode lock
    1. The vitara does not come back perfectly on wavelength and bandwidth every time. However, it should modelock. If it does not modelock at 800 nm, or doesn't stay modelocked call the SLSO
  2. Build up in regen doesn't match shutdown image
    1. Either Vitara pointing has changed (unlikely)
    2. Vitara power output is low (compare Vitara power now to records at time of shutdown)
    3. Regen triggers are bad. Check the SLAC triggers
  3. Pre-amp or MPA output is low
    1. Pointing through the MPA has shifted (this can happen if temp/humidity control is lost due to a power outage)
    2. Check regen and MPA images against shutdown images, has the pointing shifted?
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