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Message ID: 430     Entry time: Wed Dec 15 01:35:44 2010
Author: Frank 
Type: Notes 
Category: RefCav 
Subject: things to do 
  • replace windows on acav chamber by ar-coated windows
  • find source of reflection in cavity - my guess it is the dirty coating - the spot size is about 1cm, so it can't be a pure reflection from any of the other surfaces as the beam is too large. The concave mirror surface acts like a convex surface in reflection and intensity increases when cavity is locked.
  • clean mirrors of current cavity, replace mirrors or replace entire cavity
  • clean all optics on table - entirely and double check with real bright white-light source
  • make acav RFPD resonant or wait for new RF photodiodes to be ready
  • tune PMC RFPD to 21.5MHz (easy)
  • add AOM in RCAV path (doesn't help right now to lower phase noise or increase range of PLL)
  • lower beam height for beat setup in transmission
  • replace RFPD for pll by larger size PD
  • add notch for PMC
  • replace current FSS stuff by adv LIGO version
  • check max tuning range for wenzel vco
  • add perl script for temp feedback to acav to keep beat constant (long term stability)
  • replace LO for ACAV and RCAV by real sinewave (wenzel+amplifier)
  • change gain in RFPDs for 1mW max light
  • measure seismic on table
  • float table to see what happens (75PSI are not enough, tested today)
  • ...
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