Pre-vent checklist

• Center all oplevs/IPPOS/IPANG
• Align the arm cavities for IR and align Xgreen and Ygreen lasers to the arms.
  (X green+PSL green = TRX ~0.7 pre-swap and ~ 0.6 post-swap, Ygreen +PSL green TRY ~600 counts an hour or so after green was aligned to the arm.)
• Make a record of the MC pointing
• Align the beam at the PSL angle and position QPDs
   
  
• Record good OSEM values.
   
• Reduce input power by placing wave plate+PBS setup on the PSL table either BEFORE or AFTER THE PMC. (We will try attenuating the power using the WP + PBS that already exist after the laser. If this does not help attenuate enough, we will introduce WP+PBS after the PMC). Refer elog 6892 and elog 7299 for after the PMC detailed procedure.
   
• Replace 10% BS before MC REFL PD with Y1 mirror and lock MC at low power.
• Check the MC spot position measurement under the low power mode.
   

• Close shutter of PSL-IR and green shutters at the ends
• Make sure the jam nuts are protecting bellows