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Entry  Fri Nov 12 00:42:11 2010, rana, koji, Update, IOO, MC alignment 
    Reply  Fri Nov 12 06:10:24 2010, yuta, Update, IOO, MC aligned (without coil balancing) MCalignCALIB.png
Message ID: 3905     Entry time: Fri Nov 12 06:10:24 2010     In reply to: 3903
Author: yuta 
Type: Update 
Category: IOO 
Subject: MC aligned (without coil balancing) 

Background:
  Last night, we found that one of DAC channels are poorly connected, so we fixed the connectors.
  Rana and Koji used their incredible eyeballs to roughly align MC.
  Next thing to do is to balance the coils, but it takes some time for the setup.
  So, we decided to do A2L anyway.

What I did:
  Using the last steering mirror at PSL table and IM1, changed the incident beam direction to align MC.

Result:
MCalignCALIB.png
 
  I was amazed by their eyeballs.
  I turned the nobs of SM@PSL and IM1 in small increments, so I never lost TEM00.

Is it enough?:
  The length of the whole faraday is about 20cm and aperture diameter is about 12mm. (I couldn't measure the aperture size of the core)
  The beam is about 9mm diameter at 6w.
  So, if the beam is vertically tilted at more than ~3/200rad, it(6w) cannot go through.
  3/200 rad is about 20% difference in position at MC1 and MC3.
  So, the result meets the requirement.

  Also, assuming that coils have 5% imbalance, the beam position I measured have ~3% error.
  So, to do more precise beam centering, we need to balance the coils.

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