QPD# QPD1 QPD2
Housing# #004 #008
Diode# #44 #46
Shim (see OMC ELOG 323)
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Power Incident 252.3 uW 266.0 uW
Sum Out 174.2 mV 176.0 mV +0.3
Vertical Out + 4.7 mV +19.0 mV +0.2
Horizontal Out -16.1 mV - 8.0 mV +0.0
SEG1 -52.4 mV -53. mV -0.1
SEG2 -37.6 mV -47. mV -0.1
SEG3 -41.8 mV -34. mV -0.1
SEG4 -43.7 mV -36. mV -0.1
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Spot position X +39 um +15. um (positive = more power on SEG1 and SEG4)
Spot position Y - 8.1 um -56. um (positive = more power on SEG3 and SEG4)
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Responsivity[A/W] 0.69 0.66
Q.E. 0.80 0.77
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Arrangement of the segments
View from the beam
/ 2 | 1 X
|---+---|
\ 3 | 4 /
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I(w,x,y) = Exp[-2 (x^2 + y^2)/w^2]/(Pi w^2/2)
(SEG_A+SEG_B-SEG_C-SEG_D)/(SEG_A+SEG_B+SEG_C+SEG_D) = Erf[sqrt(2) d/w]
d: distance of the spot from the center
w: beam width
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