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Entry  Mon Jul 12 15:49:56 2010, nancy, Update, SUS, Characterisation of the QPD fullyaw.jpgyaw_linear.jpgfullpitch.jpgpitch_linear.jpg
    Reply  Mon Jul 12 17:05:30 2010, nancy, Update, SUS, Characterisation of the QPD plot.pngplot.png
Message ID: 3198     Entry time: Mon Jul 12 17:05:30 2010     In reply to: 3197
Author: nancy 
Type: Update 
Category: SUS 
Subject: Characterisation of the QPD 

Quote:

I and koji setup the measurement of the QPD response to the pitch and yaw displacements of the beam spot.

We did this using a 100mW 1064nm laser. Its power was attenuated to ~ 1.9mW, and the spot size at the QPD position was 6000-7000 um .

The QPD was put on a translation stage, using which, the center of teh QPD wrt the beam spot could be moved in pitch and yaw.

Following are the measurements :

 

 The old plots looked horrible, and so here is a new plot

plot.png

The slopes and other stats are

Pitch

Linear model Poly1:
     f(x) = p1*x + p2
Coefficients (with 95% confidence bounds):
       p1 =        8550  (7684, 9417)
       p2 =       -2148  (-2390, -1906)

Goodness of fit:
  SSE: 9944
  R-square: 0.9923
  Adjusted R-square: 0.9907
  RMSE: 44.59

Yaw

Linear model Poly1:
     f(x) = p1*x + p2
Coefficients (with 95% confidence bounds):
       p1 =       -8310  (-8958, -7662)
       p2 =        2084  (1916, 2252)

Goodness of fit:
  SSE: 6923
  R-square: 0.9954
  Adjusted R-square: 0.9945
  RMSE: 37.21

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