40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log  Not logged in ELOG logo
Entry  Tue Aug 2 19:05:13 2011, kiwamu, Update, IOO, peparation for low power MC : HWP+PBS installed attenuator.png
    Reply  Wed Aug 3 04:29:48 2011, kiwamu, Update, IOO, peparation for low power MC : HWP+PBS installed 
Message ID: 5097     Entry time: Tue Aug 2 19:05:13 2011     Reply to this: 5103
Author: kiwamu 
Type: Update 
Category: IOO 
Subject: peparation for low power MC : HWP+PBS installed 

[Steve / Kiwamu]

  An attenuator, consisting of two HWPs and a PBS, has been installed on the PSL table for the MC low power state.

Those items allow us to reduce the amount of the incident power going into the MC.

We haven't decreased the power yet because we still have to measure the arm lengths.

After we finish the measurement we will go to the low power state.

We have adjusted the polarization after the last HWP using another PBS. Now it is S-polarizing beam.

After the installation of the attenuator the beam axis has changed although we were immediately able to lock the MC with TEM00 mode.

I touched two steering mirrors on the PSL table to get the transmitted power of MC higher. At the moment the transmitted power in MC_TRANS is at about 30000 cnts.

 

The attached picture is the setup of the attenuator on the PSL table.

Attachment 1: attenuator.png  1.386 MB  | Show | Show all
ELOG V3.1.3-