40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  PSL  Not logged in ELOG logo
Entry  Sun May 13 21:18:55 2018, awade, DailyProgress, BEAT, Reinstalling beam splitter and beat detector IMG_3368_DamageOnSouthBeatSteeringMirror.JPGIMG_CurrentBeatBoardLayout.JPG
    Reply  Mon May 14 09:25:44 2018, Craig, DailyProgress, BEAT, Reinstalling beam splitter and beat detector 
       Reply  Tue May 15 14:24:25 2018, awade, DailyProgress, BEAT, Reinstalling beam splitter and beat detector 
Message ID: 2185     Entry time: Tue May 15 14:24:25 2018     In reply to: 2184
Author: awade 
Type: DailyProgress 
Category: BEAT 
Subject: Reinstalling beam splitter and beat detector 

When I orient the beam into p-pol I noticed that the beam splitters give a lot of secondary reflections.  All these mirrors need to be switched out for p-pol optimized splitters and steering mirrors. 

We'll try to get all these beam dumps back in and bolted down soon.

Quote:

If I recall correctly, I placed those beam dumps everywhere because the transmission table ghost beams had gotten out of control.  Particularly bad was out of the cavity, it seems you have left those beam dumps there but I would double check their status.  There was also reflection from the first lenses back into the cavity that I tried to have the post-cav beam dumps block, unclear how successful I was. 

Also bad was reflection from the ND filter we had on our pre-RFPD lens, it seems like you have removed this lens which is great.  Also, there was some backscatter from the third camera I had installed at the other end of the recombination BS that unites the North and South path light, seems like that is gone as well, you might dump that light if you aren't already. 

Finally, the scatter from the IR cameras was like a diffraction grating pattern that went everywhere, it might be prudent to place those black glass beam dumps with the holes in front of them.

ELOG V3.1.3-