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Message ID: 1326     Entry time: Thu Feb 19 22:40:33 2009
Author: Kiwamu 
Type: Update 
Category: Electronics 
Subject: PSL angle QPD 

I checked a broken QPD, which was placed for PSL angle monitor, and finally I cocluded one segment of the quadrant diode was broken.

The broken segment has a offset voltage of -0.7V after 1st I-V amplifier. It means the diode segment has a current offset without any injection of light.

Tomorrow I will check a new QPD for replacement.

Kiwamu IZUMI

 

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